iproute2/include/uapi/linux/bpf.h
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   1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of version 2 of the GNU General Public
   6 * License as published by the Free Software Foundation.
   7 */
   8#ifndef __LINUX_BPF_H__
   9#define __LINUX_BPF_H__
  10
  11#include <linux/types.h>
  12#include <linux/bpf_common.h>
  13
  14/* Extended instruction set based on top of classic BPF */
  15
  16/* instruction classes */
  17#define BPF_JMP32       0x06    /* jmp mode in word width */
  18#define BPF_ALU64       0x07    /* alu mode in double word width */
  19
  20/* ld/ldx fields */
  21#define BPF_DW          0x18    /* double word (64-bit) */
  22#define BPF_ATOMIC      0xc0    /* atomic memory ops - op type in immediate */
  23#define BPF_XADD        0xc0    /* exclusive add - legacy name */
  24
  25/* alu/jmp fields */
  26#define BPF_MOV         0xb0    /* mov reg to reg */
  27#define BPF_ARSH        0xc0    /* sign extending arithmetic shift right */
  28
  29/* change endianness of a register */
  30#define BPF_END         0xd0    /* flags for endianness conversion: */
  31#define BPF_TO_LE       0x00    /* convert to little-endian */
  32#define BPF_TO_BE       0x08    /* convert to big-endian */
  33#define BPF_FROM_LE     BPF_TO_LE
  34#define BPF_FROM_BE     BPF_TO_BE
  35
  36/* jmp encodings */
  37#define BPF_JNE         0x50    /* jump != */
  38#define BPF_JLT         0xa0    /* LT is unsigned, '<' */
  39#define BPF_JLE         0xb0    /* LE is unsigned, '<=' */
  40#define BPF_JSGT        0x60    /* SGT is signed '>', GT in x86 */
  41#define BPF_JSGE        0x70    /* SGE is signed '>=', GE in x86 */
  42#define BPF_JSLT        0xc0    /* SLT is signed, '<' */
  43#define BPF_JSLE        0xd0    /* SLE is signed, '<=' */
  44#define BPF_CALL        0x80    /* function call */
  45#define BPF_EXIT        0x90    /* function return */
  46
  47/* atomic op type fields (stored in immediate) */
  48#define BPF_FETCH       0x01    /* not an opcode on its own, used to build others */
  49#define BPF_XCHG        (0xe0 | BPF_FETCH)      /* atomic exchange */
  50#define BPF_CMPXCHG     (0xf0 | BPF_FETCH)      /* atomic compare-and-write */
  51
  52/* Register numbers */
  53enum {
  54        BPF_REG_0 = 0,
  55        BPF_REG_1,
  56        BPF_REG_2,
  57        BPF_REG_3,
  58        BPF_REG_4,
  59        BPF_REG_5,
  60        BPF_REG_6,
  61        BPF_REG_7,
  62        BPF_REG_8,
  63        BPF_REG_9,
  64        BPF_REG_10,
  65        __MAX_BPF_REG,
  66};
  67
  68/* BPF has 10 general purpose 64-bit registers and stack frame. */
  69#define MAX_BPF_REG     __MAX_BPF_REG
  70
  71struct bpf_insn {
  72        __u8    code;           /* opcode */
  73        __u8    dst_reg:4;      /* dest register */
  74        __u8    src_reg:4;      /* source register */
  75        __s16   off;            /* signed offset */
  76        __s32   imm;            /* signed immediate constant */
  77};
  78
  79/* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
  80struct bpf_lpm_trie_key {
  81        __u32   prefixlen;      /* up to 32 for AF_INET, 128 for AF_INET6 */
  82        __u8    data[0];        /* Arbitrary size */
  83};
  84
  85struct bpf_cgroup_storage_key {
  86        __u64   cgroup_inode_id;        /* cgroup inode id */
  87        __u32   attach_type;            /* program attach type (enum bpf_attach_type) */
  88};
  89
  90union bpf_iter_link_info {
  91        struct {
  92                __u32   map_fd;
  93        } map;
  94};
  95
  96/* BPF syscall commands, see bpf(2) man-page for more details. */
  97/**
  98 * DOC: eBPF Syscall Preamble
  99 *
 100 * The operation to be performed by the **bpf**\ () system call is determined
 101 * by the *cmd* argument. Each operation takes an accompanying argument,
 102 * provided via *attr*, which is a pointer to a union of type *bpf_attr* (see
 103 * below). The size argument is the size of the union pointed to by *attr*.
 104 */
 105/**
 106 * DOC: eBPF Syscall Commands
 107 *
 108 * BPF_MAP_CREATE
 109 *      Description
 110 *              Create a map and return a file descriptor that refers to the
 111 *              map. The close-on-exec file descriptor flag (see **fcntl**\ (2))
 112 *              is automatically enabled for the new file descriptor.
 113 *
 114 *              Applying **close**\ (2) to the file descriptor returned by
 115 *              **BPF_MAP_CREATE** will delete the map (but see NOTES).
 116 *
 117 *      Return
 118 *              A new file descriptor (a nonnegative integer), or -1 if an
 119 *              error occurred (in which case, *errno* is set appropriately).
 120 *
 121 * BPF_MAP_LOOKUP_ELEM
 122 *      Description
 123 *              Look up an element with a given *key* in the map referred to
 124 *              by the file descriptor *map_fd*.
 125 *
 126 *              The *flags* argument may be specified as one of the
 127 *              following:
 128 *
 129 *              **BPF_F_LOCK**
 130 *                      Look up the value of a spin-locked map without
 131 *                      returning the lock. This must be specified if the
 132 *                      elements contain a spinlock.
 133 *
 134 *      Return
 135 *              Returns zero on success. On error, -1 is returned and *errno*
 136 *              is set appropriately.
 137 *
 138 * BPF_MAP_UPDATE_ELEM
 139 *      Description
 140 *              Create or update an element (key/value pair) in a specified map.
 141 *
 142 *              The *flags* argument should be specified as one of the
 143 *              following:
 144 *
 145 *              **BPF_ANY**
 146 *                      Create a new element or update an existing element.
 147 *              **BPF_NOEXIST**
 148 *                      Create a new element only if it did not exist.
 149 *              **BPF_EXIST**
 150 *                      Update an existing element.
 151 *              **BPF_F_LOCK**
 152 *                      Update a spin_lock-ed map element.
 153 *
 154 *      Return
 155 *              Returns zero on success. On error, -1 is returned and *errno*
 156 *              is set appropriately.
 157 *
 158 *              May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**,
 159 *              **E2BIG**, **EEXIST**, or **ENOENT**.
 160 *
 161 *              **E2BIG**
 162 *                      The number of elements in the map reached the
 163 *                      *max_entries* limit specified at map creation time.
 164 *              **EEXIST**
 165 *                      If *flags* specifies **BPF_NOEXIST** and the element
 166 *                      with *key* already exists in the map.
 167 *              **ENOENT**
 168 *                      If *flags* specifies **BPF_EXIST** and the element with
 169 *                      *key* does not exist in the map.
 170 *
 171 * BPF_MAP_DELETE_ELEM
 172 *      Description
 173 *              Look up and delete an element by key in a specified map.
 174 *
 175 *      Return
 176 *              Returns zero on success. On error, -1 is returned and *errno*
 177 *              is set appropriately.
 178 *
 179 * BPF_MAP_GET_NEXT_KEY
 180 *      Description
 181 *              Look up an element by key in a specified map and return the key
 182 *              of the next element. Can be used to iterate over all elements
 183 *              in the map.
 184 *
 185 *      Return
 186 *              Returns zero on success. On error, -1 is returned and *errno*
 187 *              is set appropriately.
 188 *
 189 *              The following cases can be used to iterate over all elements of
 190 *              the map:
 191 *
 192 *              * If *key* is not found, the operation returns zero and sets
 193 *                the *next_key* pointer to the key of the first element.
 194 *              * If *key* is found, the operation returns zero and sets the
 195 *                *next_key* pointer to the key of the next element.
 196 *              * If *key* is the last element, returns -1 and *errno* is set
 197 *                to **ENOENT**.
 198 *
 199 *              May set *errno* to **ENOMEM**, **EFAULT**, **EPERM**, or
 200 *              **EINVAL** on error.
 201 *
 202 * BPF_PROG_LOAD
 203 *      Description
 204 *              Verify and load an eBPF program, returning a new file
 205 *              descriptor associated with the program.
 206 *
 207 *              Applying **close**\ (2) to the file descriptor returned by
 208 *              **BPF_PROG_LOAD** will unload the eBPF program (but see NOTES).
 209 *
 210 *              The close-on-exec file descriptor flag (see **fcntl**\ (2)) is
 211 *              automatically enabled for the new file descriptor.
 212 *
 213 *      Return
 214 *              A new file descriptor (a nonnegative integer), or -1 if an
 215 *              error occurred (in which case, *errno* is set appropriately).
 216 *
 217 * BPF_OBJ_PIN
 218 *      Description
 219 *              Pin an eBPF program or map referred by the specified *bpf_fd*
 220 *              to the provided *pathname* on the filesystem.
 221 *
 222 *              The *pathname* argument must not contain a dot (".").
 223 *
 224 *              On success, *pathname* retains a reference to the eBPF object,
 225 *              preventing deallocation of the object when the original
 226 *              *bpf_fd* is closed. This allow the eBPF object to live beyond
 227 *              **close**\ (\ *bpf_fd*\ ), and hence the lifetime of the parent
 228 *              process.
 229 *
 230 *              Applying **unlink**\ (2) or similar calls to the *pathname*
 231 *              unpins the object from the filesystem, removing the reference.
 232 *              If no other file descriptors or filesystem nodes refer to the
 233 *              same object, it will be deallocated (see NOTES).
 234 *
 235 *              The filesystem type for the parent directory of *pathname* must
 236 *              be **BPF_FS_MAGIC**.
 237 *
 238 *      Return
 239 *              Returns zero on success. On error, -1 is returned and *errno*
 240 *              is set appropriately.
 241 *
 242 * BPF_OBJ_GET
 243 *      Description
 244 *              Open a file descriptor for the eBPF object pinned to the
 245 *              specified *pathname*.
 246 *
 247 *      Return
 248 *              A new file descriptor (a nonnegative integer), or -1 if an
 249 *              error occurred (in which case, *errno* is set appropriately).
 250 *
 251 * BPF_PROG_ATTACH
 252 *      Description
 253 *              Attach an eBPF program to a *target_fd* at the specified
 254 *              *attach_type* hook.
 255 *
 256 *              The *attach_type* specifies the eBPF attachment point to
 257 *              attach the program to, and must be one of *bpf_attach_type*
 258 *              (see below).
 259 *
 260 *              The *attach_bpf_fd* must be a valid file descriptor for a
 261 *              loaded eBPF program of a cgroup, flow dissector, LIRC, sockmap
 262 *              or sock_ops type corresponding to the specified *attach_type*.
 263 *
 264 *              The *target_fd* must be a valid file descriptor for a kernel
 265 *              object which depends on the attach type of *attach_bpf_fd*:
 266 *
 267 *              **BPF_PROG_TYPE_CGROUP_DEVICE**,
 268 *              **BPF_PROG_TYPE_CGROUP_SKB**,
 269 *              **BPF_PROG_TYPE_CGROUP_SOCK**,
 270 *              **BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
 271 *              **BPF_PROG_TYPE_CGROUP_SOCKOPT**,
 272 *              **BPF_PROG_TYPE_CGROUP_SYSCTL**,
 273 *              **BPF_PROG_TYPE_SOCK_OPS**
 274 *
 275 *                      Control Group v2 hierarchy with the eBPF controller
 276 *                      enabled. Requires the kernel to be compiled with
 277 *                      **CONFIG_CGROUP_BPF**.
 278 *
 279 *              **BPF_PROG_TYPE_FLOW_DISSECTOR**
 280 *
 281 *                      Network namespace (eg /proc/self/ns/net).
 282 *
 283 *              **BPF_PROG_TYPE_LIRC_MODE2**
 284 *
 285 *                      LIRC device path (eg /dev/lircN). Requires the kernel
 286 *                      to be compiled with **CONFIG_BPF_LIRC_MODE2**.
 287 *
 288 *              **BPF_PROG_TYPE_SK_SKB**,
 289 *              **BPF_PROG_TYPE_SK_MSG**
 290 *
 291 *                      eBPF map of socket type (eg **BPF_MAP_TYPE_SOCKHASH**).
 292 *
 293 *      Return
 294 *              Returns zero on success. On error, -1 is returned and *errno*
 295 *              is set appropriately.
 296 *
 297 * BPF_PROG_DETACH
 298 *      Description
 299 *              Detach the eBPF program associated with the *target_fd* at the
 300 *              hook specified by *attach_type*. The program must have been
 301 *              previously attached using **BPF_PROG_ATTACH**.
 302 *
 303 *      Return
 304 *              Returns zero on success. On error, -1 is returned and *errno*
 305 *              is set appropriately.
 306 *
 307 * BPF_PROG_TEST_RUN
 308 *      Description
 309 *              Run the eBPF program associated with the *prog_fd* a *repeat*
 310 *              number of times against a provided program context *ctx_in* and
 311 *              data *data_in*, and return the modified program context
 312 *              *ctx_out*, *data_out* (for example, packet data), result of the
 313 *              execution *retval*, and *duration* of the test run.
 314 *
 315 *              The sizes of the buffers provided as input and output
 316 *              parameters *ctx_in*, *ctx_out*, *data_in*, and *data_out* must
 317 *              be provided in the corresponding variables *ctx_size_in*,
 318 *              *ctx_size_out*, *data_size_in*, and/or *data_size_out*. If any
 319 *              of these parameters are not provided (ie set to NULL), the
 320 *              corresponding size field must be zero.
 321 *
 322 *              Some program types have particular requirements:
 323 *
 324 *              **BPF_PROG_TYPE_SK_LOOKUP**
 325 *                      *data_in* and *data_out* must be NULL.
 326 *
 327 *              **BPF_PROG_TYPE_RAW_TRACEPOINT**,
 328 *              **BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE**
 329 *
 330 *                      *ctx_out*, *data_in* and *data_out* must be NULL.
 331 *                      *repeat* must be zero.
 332 *
 333 *      Return
 334 *              Returns zero on success. On error, -1 is returned and *errno*
 335 *              is set appropriately.
 336 *
 337 *              **ENOSPC**
 338 *                      Either *data_size_out* or *ctx_size_out* is too small.
 339 *              **ENOTSUPP**
 340 *                      This command is not supported by the program type of
 341 *                      the program referred to by *prog_fd*.
 342 *
 343 * BPF_PROG_GET_NEXT_ID
 344 *      Description
 345 *              Fetch the next eBPF program currently loaded into the kernel.
 346 *
 347 *              Looks for the eBPF program with an id greater than *start_id*
 348 *              and updates *next_id* on success. If no other eBPF programs
 349 *              remain with ids higher than *start_id*, returns -1 and sets
 350 *              *errno* to **ENOENT**.
 351 *
 352 *      Return
 353 *              Returns zero on success. On error, or when no id remains, -1
 354 *              is returned and *errno* is set appropriately.
 355 *
 356 * BPF_MAP_GET_NEXT_ID
 357 *      Description
 358 *              Fetch the next eBPF map currently loaded into the kernel.
 359 *
 360 *              Looks for the eBPF map with an id greater than *start_id*
 361 *              and updates *next_id* on success. If no other eBPF maps
 362 *              remain with ids higher than *start_id*, returns -1 and sets
 363 *              *errno* to **ENOENT**.
 364 *
 365 *      Return
 366 *              Returns zero on success. On error, or when no id remains, -1
 367 *              is returned and *errno* is set appropriately.
 368 *
 369 * BPF_PROG_GET_FD_BY_ID
 370 *      Description
 371 *              Open a file descriptor for the eBPF program corresponding to
 372 *              *prog_id*.
 373 *
 374 *      Return
 375 *              A new file descriptor (a nonnegative integer), or -1 if an
 376 *              error occurred (in which case, *errno* is set appropriately).
 377 *
 378 * BPF_MAP_GET_FD_BY_ID
 379 *      Description
 380 *              Open a file descriptor for the eBPF map corresponding to
 381 *              *map_id*.
 382 *
 383 *      Return
 384 *              A new file descriptor (a nonnegative integer), or -1 if an
 385 *              error occurred (in which case, *errno* is set appropriately).
 386 *
 387 * BPF_OBJ_GET_INFO_BY_FD
 388 *      Description
 389 *              Obtain information about the eBPF object corresponding to
 390 *              *bpf_fd*.
 391 *
 392 *              Populates up to *info_len* bytes of *info*, which will be in
 393 *              one of the following formats depending on the eBPF object type
 394 *              of *bpf_fd*:
 395 *
 396 *              * **struct bpf_prog_info**
 397 *              * **struct bpf_map_info**
 398 *              * **struct bpf_btf_info**
 399 *              * **struct bpf_link_info**
 400 *
 401 *      Return
 402 *              Returns zero on success. On error, -1 is returned and *errno*
 403 *              is set appropriately.
 404 *
 405 * BPF_PROG_QUERY
 406 *      Description
 407 *              Obtain information about eBPF programs associated with the
 408 *              specified *attach_type* hook.
 409 *
 410 *              The *target_fd* must be a valid file descriptor for a kernel
 411 *              object which depends on the attach type of *attach_bpf_fd*:
 412 *
 413 *              **BPF_PROG_TYPE_CGROUP_DEVICE**,
 414 *              **BPF_PROG_TYPE_CGROUP_SKB**,
 415 *              **BPF_PROG_TYPE_CGROUP_SOCK**,
 416 *              **BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
 417 *              **BPF_PROG_TYPE_CGROUP_SOCKOPT**,
 418 *              **BPF_PROG_TYPE_CGROUP_SYSCTL**,
 419 *              **BPF_PROG_TYPE_SOCK_OPS**
 420 *
 421 *                      Control Group v2 hierarchy with the eBPF controller
 422 *                      enabled. Requires the kernel to be compiled with
 423 *                      **CONFIG_CGROUP_BPF**.
 424 *
 425 *              **BPF_PROG_TYPE_FLOW_DISSECTOR**
 426 *
 427 *                      Network namespace (eg /proc/self/ns/net).
 428 *
 429 *              **BPF_PROG_TYPE_LIRC_MODE2**
 430 *
 431 *                      LIRC device path (eg /dev/lircN). Requires the kernel
 432 *                      to be compiled with **CONFIG_BPF_LIRC_MODE2**.
 433 *
 434 *              **BPF_PROG_QUERY** always fetches the number of programs
 435 *              attached and the *attach_flags* which were used to attach those
 436 *              programs. Additionally, if *prog_ids* is nonzero and the number
 437 *              of attached programs is less than *prog_cnt*, populates
 438 *              *prog_ids* with the eBPF program ids of the programs attached
 439 *              at *target_fd*.
 440 *
 441 *              The following flags may alter the result:
 442 *
 443 *              **BPF_F_QUERY_EFFECTIVE**
 444 *                      Only return information regarding programs which are
 445 *                      currently effective at the specified *target_fd*.
 446 *
 447 *      Return
 448 *              Returns zero on success. On error, -1 is returned and *errno*
 449 *              is set appropriately.
 450 *
 451 * BPF_RAW_TRACEPOINT_OPEN
 452 *      Description
 453 *              Attach an eBPF program to a tracepoint *name* to access kernel
 454 *              internal arguments of the tracepoint in their raw form.
 455 *
 456 *              The *prog_fd* must be a valid file descriptor associated with
 457 *              a loaded eBPF program of type **BPF_PROG_TYPE_RAW_TRACEPOINT**.
 458 *
 459 *              No ABI guarantees are made about the content of tracepoint
 460 *              arguments exposed to the corresponding eBPF program.
 461 *
 462 *              Applying **close**\ (2) to the file descriptor returned by
 463 *              **BPF_RAW_TRACEPOINT_OPEN** will delete the map (but see NOTES).
 464 *
 465 *      Return
 466 *              A new file descriptor (a nonnegative integer), or -1 if an
 467 *              error occurred (in which case, *errno* is set appropriately).
 468 *
 469 * BPF_BTF_LOAD
 470 *      Description
 471 *              Verify and load BPF Type Format (BTF) metadata into the kernel,
 472 *              returning a new file descriptor associated with the metadata.
 473 *              BTF is described in more detail at
 474 *              https://www.kernel.org/doc/html/latest/bpf/btf.html.
 475 *
 476 *              The *btf* parameter must point to valid memory providing
 477 *              *btf_size* bytes of BTF binary metadata.
 478 *
 479 *              The returned file descriptor can be passed to other **bpf**\ ()
 480 *              subcommands such as **BPF_PROG_LOAD** or **BPF_MAP_CREATE** to
 481 *              associate the BTF with those objects.
 482 *
 483 *              Similar to **BPF_PROG_LOAD**, **BPF_BTF_LOAD** has optional
 484 *              parameters to specify a *btf_log_buf*, *btf_log_size* and
 485 *              *btf_log_level* which allow the kernel to return freeform log
 486 *              output regarding the BTF verification process.
 487 *
 488 *      Return
 489 *              A new file descriptor (a nonnegative integer), or -1 if an
 490 *              error occurred (in which case, *errno* is set appropriately).
 491 *
 492 * BPF_BTF_GET_FD_BY_ID
 493 *      Description
 494 *              Open a file descriptor for the BPF Type Format (BTF)
 495 *              corresponding to *btf_id*.
 496 *
 497 *      Return
 498 *              A new file descriptor (a nonnegative integer), or -1 if an
 499 *              error occurred (in which case, *errno* is set appropriately).
 500 *
 501 * BPF_TASK_FD_QUERY
 502 *      Description
 503 *              Obtain information about eBPF programs associated with the
 504 *              target process identified by *pid* and *fd*.
 505 *
 506 *              If the *pid* and *fd* are associated with a tracepoint, kprobe
 507 *              or uprobe perf event, then the *prog_id* and *fd_type* will
 508 *              be populated with the eBPF program id and file descriptor type
 509 *              of type **bpf_task_fd_type**. If associated with a kprobe or
 510 *              uprobe, the  *probe_offset* and *probe_addr* will also be
 511 *              populated. Optionally, if *buf* is provided, then up to
 512 *              *buf_len* bytes of *buf* will be populated with the name of
 513 *              the tracepoint, kprobe or uprobe.
 514 *
 515 *              The resulting *prog_id* may be introspected in deeper detail
 516 *              using **BPF_PROG_GET_FD_BY_ID** and **BPF_OBJ_GET_INFO_BY_FD**.
 517 *
 518 *      Return
 519 *              Returns zero on success. On error, -1 is returned and *errno*
 520 *              is set appropriately.
 521 *
 522 * BPF_MAP_LOOKUP_AND_DELETE_ELEM
 523 *      Description
 524 *              Look up an element with the given *key* in the map referred to
 525 *              by the file descriptor *fd*, and if found, delete the element.
 526 *
 527 *              For **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map
 528 *              types, the *flags* argument needs to be set to 0, but for other
 529 *              map types, it may be specified as:
 530 *
 531 *              **BPF_F_LOCK**
 532 *                      Look up and delete the value of a spin-locked map
 533 *                      without returning the lock. This must be specified if
 534 *                      the elements contain a spinlock.
 535 *
 536 *              The **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map types
 537 *              implement this command as a "pop" operation, deleting the top
 538 *              element rather than one corresponding to *key*.
 539 *              The *key* and *key_len* parameters should be zeroed when
 540 *              issuing this operation for these map types.
 541 *
 542 *              This command is only valid for the following map types:
 543 *              * **BPF_MAP_TYPE_QUEUE**
 544 *              * **BPF_MAP_TYPE_STACK**
 545 *              * **BPF_MAP_TYPE_HASH**
 546 *              * **BPF_MAP_TYPE_PERCPU_HASH**
 547 *              * **BPF_MAP_TYPE_LRU_HASH**
 548 *              * **BPF_MAP_TYPE_LRU_PERCPU_HASH**
 549 *
 550 *      Return
 551 *              Returns zero on success. On error, -1 is returned and *errno*
 552 *              is set appropriately.
 553 *
 554 * BPF_MAP_FREEZE
 555 *      Description
 556 *              Freeze the permissions of the specified map.
 557 *
 558 *              Write permissions may be frozen by passing zero *flags*.
 559 *              Upon success, no future syscall invocations may alter the
 560 *              map state of *map_fd*. Write operations from eBPF programs
 561 *              are still possible for a frozen map.
 562 *
 563 *              Not supported for maps of type **BPF_MAP_TYPE_STRUCT_OPS**.
 564 *
 565 *      Return
 566 *              Returns zero on success. On error, -1 is returned and *errno*
 567 *              is set appropriately.
 568 *
 569 * BPF_BTF_GET_NEXT_ID
 570 *      Description
 571 *              Fetch the next BPF Type Format (BTF) object currently loaded
 572 *              into the kernel.
 573 *
 574 *              Looks for the BTF object with an id greater than *start_id*
 575 *              and updates *next_id* on success. If no other BTF objects
 576 *              remain with ids higher than *start_id*, returns -1 and sets
 577 *              *errno* to **ENOENT**.
 578 *
 579 *      Return
 580 *              Returns zero on success. On error, or when no id remains, -1
 581 *              is returned and *errno* is set appropriately.
 582 *
 583 * BPF_MAP_LOOKUP_BATCH
 584 *      Description
 585 *              Iterate and fetch multiple elements in a map.
 586 *
 587 *              Two opaque values are used to manage batch operations,
 588 *              *in_batch* and *out_batch*. Initially, *in_batch* must be set
 589 *              to NULL to begin the batched operation. After each subsequent
 590 *              **BPF_MAP_LOOKUP_BATCH**, the caller should pass the resultant
 591 *              *out_batch* as the *in_batch* for the next operation to
 592 *              continue iteration from the current point.
 593 *
 594 *              The *keys* and *values* are output parameters which must point
 595 *              to memory large enough to hold *count* items based on the key
 596 *              and value size of the map *map_fd*. The *keys* buffer must be
 597 *              of *key_size* * *count*. The *values* buffer must be of
 598 *              *value_size* * *count*.
 599 *
 600 *              The *elem_flags* argument may be specified as one of the
 601 *              following:
 602 *
 603 *              **BPF_F_LOCK**
 604 *                      Look up the value of a spin-locked map without
 605 *                      returning the lock. This must be specified if the
 606 *                      elements contain a spinlock.
 607 *
 608 *              On success, *count* elements from the map are copied into the
 609 *              user buffer, with the keys copied into *keys* and the values
 610 *              copied into the corresponding indices in *values*.
 611 *
 612 *              If an error is returned and *errno* is not **EFAULT**, *count*
 613 *              is set to the number of successfully processed elements.
 614 *
 615 *      Return
 616 *              Returns zero on success. On error, -1 is returned and *errno*
 617 *              is set appropriately.
 618 *
 619 *              May set *errno* to **ENOSPC** to indicate that *keys* or
 620 *              *values* is too small to dump an entire bucket during
 621 *              iteration of a hash-based map type.
 622 *
 623 * BPF_MAP_LOOKUP_AND_DELETE_BATCH
 624 *      Description
 625 *              Iterate and delete all elements in a map.
 626 *
 627 *              This operation has the same behavior as
 628 *              **BPF_MAP_LOOKUP_BATCH** with two exceptions:
 629 *
 630 *              * Every element that is successfully returned is also deleted
 631 *                from the map. This is at least *count* elements. Note that
 632 *                *count* is both an input and an output parameter.
 633 *              * Upon returning with *errno* set to **EFAULT**, up to
 634 *                *count* elements may be deleted without returning the keys
 635 *                and values of the deleted elements.
 636 *
 637 *      Return
 638 *              Returns zero on success. On error, -1 is returned and *errno*
 639 *              is set appropriately.
 640 *
 641 * BPF_MAP_UPDATE_BATCH
 642 *      Description
 643 *              Update multiple elements in a map by *key*.
 644 *
 645 *              The *keys* and *values* are input parameters which must point
 646 *              to memory large enough to hold *count* items based on the key
 647 *              and value size of the map *map_fd*. The *keys* buffer must be
 648 *              of *key_size* * *count*. The *values* buffer must be of
 649 *              *value_size* * *count*.
 650 *
 651 *              Each element specified in *keys* is sequentially updated to the
 652 *              value in the corresponding index in *values*. The *in_batch*
 653 *              and *out_batch* parameters are ignored and should be zeroed.
 654 *
 655 *              The *elem_flags* argument should be specified as one of the
 656 *              following:
 657 *
 658 *              **BPF_ANY**
 659 *                      Create new elements or update a existing elements.
 660 *              **BPF_NOEXIST**
 661 *                      Create new elements only if they do not exist.
 662 *              **BPF_EXIST**
 663 *                      Update existing elements.
 664 *              **BPF_F_LOCK**
 665 *                      Update spin_lock-ed map elements. This must be
 666 *                      specified if the map value contains a spinlock.
 667 *
 668 *              On success, *count* elements from the map are updated.
 669 *
 670 *              If an error is returned and *errno* is not **EFAULT**, *count*
 671 *              is set to the number of successfully processed elements.
 672 *
 673 *      Return
 674 *              Returns zero on success. On error, -1 is returned and *errno*
 675 *              is set appropriately.
 676 *
 677 *              May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**, or
 678 *              **E2BIG**. **E2BIG** indicates that the number of elements in
 679 *              the map reached the *max_entries* limit specified at map
 680 *              creation time.
 681 *
 682 *              May set *errno* to one of the following error codes under
 683 *              specific circumstances:
 684 *
 685 *              **EEXIST**
 686 *                      If *flags* specifies **BPF_NOEXIST** and the element
 687 *                      with *key* already exists in the map.
 688 *              **ENOENT**
 689 *                      If *flags* specifies **BPF_EXIST** and the element with
 690 *                      *key* does not exist in the map.
 691 *
 692 * BPF_MAP_DELETE_BATCH
 693 *      Description
 694 *              Delete multiple elements in a map by *key*.
 695 *
 696 *              The *keys* parameter is an input parameter which must point
 697 *              to memory large enough to hold *count* items based on the key
 698 *              size of the map *map_fd*, that is, *key_size* * *count*.
 699 *
 700 *              Each element specified in *keys* is sequentially deleted. The
 701 *              *in_batch*, *out_batch*, and *values* parameters are ignored
 702 *              and should be zeroed.
 703 *
 704 *              The *elem_flags* argument may be specified as one of the
 705 *              following:
 706 *
 707 *              **BPF_F_LOCK**
 708 *                      Look up the value of a spin-locked map without
 709 *                      returning the lock. This must be specified if the
 710 *                      elements contain a spinlock.
 711 *
 712 *              On success, *count* elements from the map are updated.
 713 *
 714 *              If an error is returned and *errno* is not **EFAULT**, *count*
 715 *              is set to the number of successfully processed elements. If
 716 *              *errno* is **EFAULT**, up to *count* elements may be been
 717 *              deleted.
 718 *
 719 *      Return
 720 *              Returns zero on success. On error, -1 is returned and *errno*
 721 *              is set appropriately.
 722 *
 723 * BPF_LINK_CREATE
 724 *      Description
 725 *              Attach an eBPF program to a *target_fd* at the specified
 726 *              *attach_type* hook and return a file descriptor handle for
 727 *              managing the link.
 728 *
 729 *      Return
 730 *              A new file descriptor (a nonnegative integer), or -1 if an
 731 *              error occurred (in which case, *errno* is set appropriately).
 732 *
 733 * BPF_LINK_UPDATE
 734 *      Description
 735 *              Update the eBPF program in the specified *link_fd* to
 736 *              *new_prog_fd*.
 737 *
 738 *      Return
 739 *              Returns zero on success. On error, -1 is returned and *errno*
 740 *              is set appropriately.
 741 *
 742 * BPF_LINK_GET_FD_BY_ID
 743 *      Description
 744 *              Open a file descriptor for the eBPF Link corresponding to
 745 *              *link_id*.
 746 *
 747 *      Return
 748 *              A new file descriptor (a nonnegative integer), or -1 if an
 749 *              error occurred (in which case, *errno* is set appropriately).
 750 *
 751 * BPF_LINK_GET_NEXT_ID
 752 *      Description
 753 *              Fetch the next eBPF link currently loaded into the kernel.
 754 *
 755 *              Looks for the eBPF link with an id greater than *start_id*
 756 *              and updates *next_id* on success. If no other eBPF links
 757 *              remain with ids higher than *start_id*, returns -1 and sets
 758 *              *errno* to **ENOENT**.
 759 *
 760 *      Return
 761 *              Returns zero on success. On error, or when no id remains, -1
 762 *              is returned and *errno* is set appropriately.
 763 *
 764 * BPF_ENABLE_STATS
 765 *      Description
 766 *              Enable eBPF runtime statistics gathering.
 767 *
 768 *              Runtime statistics gathering for the eBPF runtime is disabled
 769 *              by default to minimize the corresponding performance overhead.
 770 *              This command enables statistics globally.
 771 *
 772 *              Multiple programs may independently enable statistics.
 773 *              After gathering the desired statistics, eBPF runtime statistics
 774 *              may be disabled again by calling **close**\ (2) for the file
 775 *              descriptor returned by this function. Statistics will only be
 776 *              disabled system-wide when all outstanding file descriptors
 777 *              returned by prior calls for this subcommand are closed.
 778 *
 779 *      Return
 780 *              A new file descriptor (a nonnegative integer), or -1 if an
 781 *              error occurred (in which case, *errno* is set appropriately).
 782 *
 783 * BPF_ITER_CREATE
 784 *      Description
 785 *              Create an iterator on top of the specified *link_fd* (as
 786 *              previously created using **BPF_LINK_CREATE**) and return a
 787 *              file descriptor that can be used to trigger the iteration.
 788 *
 789 *              If the resulting file descriptor is pinned to the filesystem
 790 *              using  **BPF_OBJ_PIN**, then subsequent **read**\ (2) syscalls
 791 *              for that path will trigger the iterator to read kernel state
 792 *              using the eBPF program attached to *link_fd*.
 793 *
 794 *      Return
 795 *              A new file descriptor (a nonnegative integer), or -1 if an
 796 *              error occurred (in which case, *errno* is set appropriately).
 797 *
 798 * BPF_LINK_DETACH
 799 *      Description
 800 *              Forcefully detach the specified *link_fd* from its
 801 *              corresponding attachment point.
 802 *
 803 *      Return
 804 *              Returns zero on success. On error, -1 is returned and *errno*
 805 *              is set appropriately.
 806 *
 807 * BPF_PROG_BIND_MAP
 808 *      Description
 809 *              Bind a map to the lifetime of an eBPF program.
 810 *
 811 *              The map identified by *map_fd* is bound to the program
 812 *              identified by *prog_fd* and only released when *prog_fd* is
 813 *              released. This may be used in cases where metadata should be
 814 *              associated with a program which otherwise does not contain any
 815 *              references to the map (for example, embedded in the eBPF
 816 *              program instructions).
 817 *
 818 *      Return
 819 *              Returns zero on success. On error, -1 is returned and *errno*
 820 *              is set appropriately.
 821 *
 822 * NOTES
 823 *      eBPF objects (maps and programs) can be shared between processes.
 824 *
 825 *      * After **fork**\ (2), the child inherits file descriptors
 826 *        referring to the same eBPF objects.
 827 *      * File descriptors referring to eBPF objects can be transferred over
 828 *        **unix**\ (7) domain sockets.
 829 *      * File descriptors referring to eBPF objects can be duplicated in the
 830 *        usual way, using **dup**\ (2) and similar calls.
 831 *      * File descriptors referring to eBPF objects can be pinned to the
 832 *        filesystem using the **BPF_OBJ_PIN** command of **bpf**\ (2).
 833 *
 834 *      An eBPF object is deallocated only after all file descriptors referring
 835 *      to the object have been closed and no references remain pinned to the
 836 *      filesystem or attached (for example, bound to a program or device).
 837 */
 838enum bpf_cmd {
 839        BPF_MAP_CREATE,
 840        BPF_MAP_LOOKUP_ELEM,
 841        BPF_MAP_UPDATE_ELEM,
 842        BPF_MAP_DELETE_ELEM,
 843        BPF_MAP_GET_NEXT_KEY,
 844        BPF_PROG_LOAD,
 845        BPF_OBJ_PIN,
 846        BPF_OBJ_GET,
 847        BPF_PROG_ATTACH,
 848        BPF_PROG_DETACH,
 849        BPF_PROG_TEST_RUN,
 850        BPF_PROG_RUN = BPF_PROG_TEST_RUN,
 851        BPF_PROG_GET_NEXT_ID,
 852        BPF_MAP_GET_NEXT_ID,
 853        BPF_PROG_GET_FD_BY_ID,
 854        BPF_MAP_GET_FD_BY_ID,
 855        BPF_OBJ_GET_INFO_BY_FD,
 856        BPF_PROG_QUERY,
 857        BPF_RAW_TRACEPOINT_OPEN,
 858        BPF_BTF_LOAD,
 859        BPF_BTF_GET_FD_BY_ID,
 860        BPF_TASK_FD_QUERY,
 861        BPF_MAP_LOOKUP_AND_DELETE_ELEM,
 862        BPF_MAP_FREEZE,
 863        BPF_BTF_GET_NEXT_ID,
 864        BPF_MAP_LOOKUP_BATCH,
 865        BPF_MAP_LOOKUP_AND_DELETE_BATCH,
 866        BPF_MAP_UPDATE_BATCH,
 867        BPF_MAP_DELETE_BATCH,
 868        BPF_LINK_CREATE,
 869        BPF_LINK_UPDATE,
 870        BPF_LINK_GET_FD_BY_ID,
 871        BPF_LINK_GET_NEXT_ID,
 872        BPF_ENABLE_STATS,
 873        BPF_ITER_CREATE,
 874        BPF_LINK_DETACH,
 875        BPF_PROG_BIND_MAP,
 876};
 877
 878enum bpf_map_type {
 879        BPF_MAP_TYPE_UNSPEC,
 880        BPF_MAP_TYPE_HASH,
 881        BPF_MAP_TYPE_ARRAY,
 882        BPF_MAP_TYPE_PROG_ARRAY,
 883        BPF_MAP_TYPE_PERF_EVENT_ARRAY,
 884        BPF_MAP_TYPE_PERCPU_HASH,
 885        BPF_MAP_TYPE_PERCPU_ARRAY,
 886        BPF_MAP_TYPE_STACK_TRACE,
 887        BPF_MAP_TYPE_CGROUP_ARRAY,
 888        BPF_MAP_TYPE_LRU_HASH,
 889        BPF_MAP_TYPE_LRU_PERCPU_HASH,
 890        BPF_MAP_TYPE_LPM_TRIE,
 891        BPF_MAP_TYPE_ARRAY_OF_MAPS,
 892        BPF_MAP_TYPE_HASH_OF_MAPS,
 893        BPF_MAP_TYPE_DEVMAP,
 894        BPF_MAP_TYPE_SOCKMAP,
 895        BPF_MAP_TYPE_CPUMAP,
 896        BPF_MAP_TYPE_XSKMAP,
 897        BPF_MAP_TYPE_SOCKHASH,
 898        BPF_MAP_TYPE_CGROUP_STORAGE,
 899        BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
 900        BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
 901        BPF_MAP_TYPE_QUEUE,
 902        BPF_MAP_TYPE_STACK,
 903        BPF_MAP_TYPE_SK_STORAGE,
 904        BPF_MAP_TYPE_DEVMAP_HASH,
 905        BPF_MAP_TYPE_STRUCT_OPS,
 906        BPF_MAP_TYPE_RINGBUF,
 907        BPF_MAP_TYPE_INODE_STORAGE,
 908        BPF_MAP_TYPE_TASK_STORAGE,
 909};
 910
 911/* Note that tracing related programs such as
 912 * BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
 913 * are not subject to a stable API since kernel internal data
 914 * structures can change from release to release and may
 915 * therefore break existing tracing BPF programs. Tracing BPF
 916 * programs correspond to /a/ specific kernel which is to be
 917 * analyzed, and not /a/ specific kernel /and/ all future ones.
 918 */
 919enum bpf_prog_type {
 920        BPF_PROG_TYPE_UNSPEC,
 921        BPF_PROG_TYPE_SOCKET_FILTER,
 922        BPF_PROG_TYPE_KPROBE,
 923        BPF_PROG_TYPE_SCHED_CLS,
 924        BPF_PROG_TYPE_SCHED_ACT,
 925        BPF_PROG_TYPE_TRACEPOINT,
 926        BPF_PROG_TYPE_XDP,
 927        BPF_PROG_TYPE_PERF_EVENT,
 928        BPF_PROG_TYPE_CGROUP_SKB,
 929        BPF_PROG_TYPE_CGROUP_SOCK,
 930        BPF_PROG_TYPE_LWT_IN,
 931        BPF_PROG_TYPE_LWT_OUT,
 932        BPF_PROG_TYPE_LWT_XMIT,
 933        BPF_PROG_TYPE_SOCK_OPS,
 934        BPF_PROG_TYPE_SK_SKB,
 935        BPF_PROG_TYPE_CGROUP_DEVICE,
 936        BPF_PROG_TYPE_SK_MSG,
 937        BPF_PROG_TYPE_RAW_TRACEPOINT,
 938        BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
 939        BPF_PROG_TYPE_LWT_SEG6LOCAL,
 940        BPF_PROG_TYPE_LIRC_MODE2,
 941        BPF_PROG_TYPE_SK_REUSEPORT,
 942        BPF_PROG_TYPE_FLOW_DISSECTOR,
 943        BPF_PROG_TYPE_CGROUP_SYSCTL,
 944        BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
 945        BPF_PROG_TYPE_CGROUP_SOCKOPT,
 946        BPF_PROG_TYPE_TRACING,
 947        BPF_PROG_TYPE_STRUCT_OPS,
 948        BPF_PROG_TYPE_EXT,
 949        BPF_PROG_TYPE_LSM,
 950        BPF_PROG_TYPE_SK_LOOKUP,
 951        BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */
 952};
 953
 954enum bpf_attach_type {
 955        BPF_CGROUP_INET_INGRESS,
 956        BPF_CGROUP_INET_EGRESS,
 957        BPF_CGROUP_INET_SOCK_CREATE,
 958        BPF_CGROUP_SOCK_OPS,
 959        BPF_SK_SKB_STREAM_PARSER,
 960        BPF_SK_SKB_STREAM_VERDICT,
 961        BPF_CGROUP_DEVICE,
 962        BPF_SK_MSG_VERDICT,
 963        BPF_CGROUP_INET4_BIND,
 964        BPF_CGROUP_INET6_BIND,
 965        BPF_CGROUP_INET4_CONNECT,
 966        BPF_CGROUP_INET6_CONNECT,
 967        BPF_CGROUP_INET4_POST_BIND,
 968        BPF_CGROUP_INET6_POST_BIND,
 969        BPF_CGROUP_UDP4_SENDMSG,
 970        BPF_CGROUP_UDP6_SENDMSG,
 971        BPF_LIRC_MODE2,
 972        BPF_FLOW_DISSECTOR,
 973        BPF_CGROUP_SYSCTL,
 974        BPF_CGROUP_UDP4_RECVMSG,
 975        BPF_CGROUP_UDP6_RECVMSG,
 976        BPF_CGROUP_GETSOCKOPT,
 977        BPF_CGROUP_SETSOCKOPT,
 978        BPF_TRACE_RAW_TP,
 979        BPF_TRACE_FENTRY,
 980        BPF_TRACE_FEXIT,
 981        BPF_MODIFY_RETURN,
 982        BPF_LSM_MAC,
 983        BPF_TRACE_ITER,
 984        BPF_CGROUP_INET4_GETPEERNAME,
 985        BPF_CGROUP_INET6_GETPEERNAME,
 986        BPF_CGROUP_INET4_GETSOCKNAME,
 987        BPF_CGROUP_INET6_GETSOCKNAME,
 988        BPF_XDP_DEVMAP,
 989        BPF_CGROUP_INET_SOCK_RELEASE,
 990        BPF_XDP_CPUMAP,
 991        BPF_SK_LOOKUP,
 992        BPF_XDP,
 993        BPF_SK_SKB_VERDICT,
 994        BPF_SK_REUSEPORT_SELECT,
 995        BPF_SK_REUSEPORT_SELECT_OR_MIGRATE,
 996        BPF_PERF_EVENT,
 997        __MAX_BPF_ATTACH_TYPE
 998};
 999
1000#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
1001
1002enum bpf_link_type {
1003        BPF_LINK_TYPE_UNSPEC = 0,
1004        BPF_LINK_TYPE_RAW_TRACEPOINT = 1,
1005        BPF_LINK_TYPE_TRACING = 2,
1006        BPF_LINK_TYPE_CGROUP = 3,
1007        BPF_LINK_TYPE_ITER = 4,
1008        BPF_LINK_TYPE_NETNS = 5,
1009        BPF_LINK_TYPE_XDP = 6,
1010        BPF_LINK_TYPE_PERF_EVENT = 7,
1011
1012        MAX_BPF_LINK_TYPE,
1013};
1014
1015/* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
1016 *
1017 * NONE(default): No further bpf programs allowed in the subtree.
1018 *
1019 * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
1020 * the program in this cgroup yields to sub-cgroup program.
1021 *
1022 * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
1023 * that cgroup program gets run in addition to the program in this cgroup.
1024 *
1025 * Only one program is allowed to be attached to a cgroup with
1026 * NONE or BPF_F_ALLOW_OVERRIDE flag.
1027 * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
1028 * release old program and attach the new one. Attach flags has to match.
1029 *
1030 * Multiple programs are allowed to be attached to a cgroup with
1031 * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
1032 * (those that were attached first, run first)
1033 * The programs of sub-cgroup are executed first, then programs of
1034 * this cgroup and then programs of parent cgroup.
1035 * When children program makes decision (like picking TCP CA or sock bind)
1036 * parent program has a chance to override it.
1037 *
1038 * With BPF_F_ALLOW_MULTI a new program is added to the end of the list of
1039 * programs for a cgroup. Though it's possible to replace an old program at
1040 * any position by also specifying BPF_F_REPLACE flag and position itself in
1041 * replace_bpf_fd attribute. Old program at this position will be released.
1042 *
1043 * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
1044 * A cgroup with NONE doesn't allow any programs in sub-cgroups.
1045 * Ex1:
1046 * cgrp1 (MULTI progs A, B) ->
1047 *    cgrp2 (OVERRIDE prog C) ->
1048 *      cgrp3 (MULTI prog D) ->
1049 *        cgrp4 (OVERRIDE prog E) ->
1050 *          cgrp5 (NONE prog F)
1051 * the event in cgrp5 triggers execution of F,D,A,B in that order.
1052 * if prog F is detached, the execution is E,D,A,B
1053 * if prog F and D are detached, the execution is E,A,B
1054 * if prog F, E and D are detached, the execution is C,A,B
1055 *
1056 * All eligible programs are executed regardless of return code from
1057 * earlier programs.
1058 */
1059#define BPF_F_ALLOW_OVERRIDE    (1U << 0)
1060#define BPF_F_ALLOW_MULTI       (1U << 1)
1061#define BPF_F_REPLACE           (1U << 2)
1062
1063/* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
1064 * verifier will perform strict alignment checking as if the kernel
1065 * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
1066 * and NET_IP_ALIGN defined to 2.
1067 */
1068#define BPF_F_STRICT_ALIGNMENT  (1U << 0)
1069
1070/* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
1071 * verifier will allow any alignment whatsoever.  On platforms
1072 * with strict alignment requirements for loads ands stores (such
1073 * as sparc and mips) the verifier validates that all loads and
1074 * stores provably follow this requirement.  This flag turns that
1075 * checking and enforcement off.
1076 *
1077 * It is mostly used for testing when we want to validate the
1078 * context and memory access aspects of the verifier, but because
1079 * of an unaligned access the alignment check would trigger before
1080 * the one we are interested in.
1081 */
1082#define BPF_F_ANY_ALIGNMENT     (1U << 1)
1083
1084/* BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose.
1085 * Verifier does sub-register def/use analysis and identifies instructions whose
1086 * def only matters for low 32-bit, high 32-bit is never referenced later
1087 * through implicit zero extension. Therefore verifier notifies JIT back-ends
1088 * that it is safe to ignore clearing high 32-bit for these instructions. This
1089 * saves some back-ends a lot of code-gen. However such optimization is not
1090 * necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends
1091 * hence hasn't used verifier's analysis result. But, we really want to have a
1092 * way to be able to verify the correctness of the described optimization on
1093 * x86_64 on which testsuites are frequently exercised.
1094 *
1095 * So, this flag is introduced. Once it is set, verifier will randomize high
1096 * 32-bit for those instructions who has been identified as safe to ignore them.
1097 * Then, if verifier is not doing correct analysis, such randomization will
1098 * regress tests to expose bugs.
1099 */
1100#define BPF_F_TEST_RND_HI32     (1U << 2)
1101
1102/* The verifier internal test flag. Behavior is undefined */
1103#define BPF_F_TEST_STATE_FREQ   (1U << 3)
1104
1105/* If BPF_F_SLEEPABLE is used in BPF_PROG_LOAD command, the verifier will
1106 * restrict map and helper usage for such programs. Sleepable BPF programs can
1107 * only be attached to hooks where kernel execution context allows sleeping.
1108 * Such programs are allowed to use helpers that may sleep like
1109 * bpf_copy_from_user().
1110 */
1111#define BPF_F_SLEEPABLE         (1U << 4)
1112
1113/* When BPF ldimm64's insn[0].src_reg != 0 then this can have
1114 * the following extensions:
1115 *
1116 * insn[0].src_reg:  BPF_PSEUDO_MAP_[FD|IDX]
1117 * insn[0].imm:      map fd or fd_idx
1118 * insn[1].imm:      0
1119 * insn[0].off:      0
1120 * insn[1].off:      0
1121 * ldimm64 rewrite:  address of map
1122 * verifier type:    CONST_PTR_TO_MAP
1123 */
1124#define BPF_PSEUDO_MAP_FD       1
1125#define BPF_PSEUDO_MAP_IDX      5
1126
1127/* insn[0].src_reg:  BPF_PSEUDO_MAP_[IDX_]VALUE
1128 * insn[0].imm:      map fd or fd_idx
1129 * insn[1].imm:      offset into value
1130 * insn[0].off:      0
1131 * insn[1].off:      0
1132 * ldimm64 rewrite:  address of map[0]+offset
1133 * verifier type:    PTR_TO_MAP_VALUE
1134 */
1135#define BPF_PSEUDO_MAP_VALUE            2
1136#define BPF_PSEUDO_MAP_IDX_VALUE        6
1137
1138/* insn[0].src_reg:  BPF_PSEUDO_BTF_ID
1139 * insn[0].imm:      kernel btd id of VAR
1140 * insn[1].imm:      0
1141 * insn[0].off:      0
1142 * insn[1].off:      0
1143 * ldimm64 rewrite:  address of the kernel variable
1144 * verifier type:    PTR_TO_BTF_ID or PTR_TO_MEM, depending on whether the var
1145 *                   is struct/union.
1146 */
1147#define BPF_PSEUDO_BTF_ID       3
1148/* insn[0].src_reg:  BPF_PSEUDO_FUNC
1149 * insn[0].imm:      insn offset to the func
1150 * insn[1].imm:      0
1151 * insn[0].off:      0
1152 * insn[1].off:      0
1153 * ldimm64 rewrite:  address of the function
1154 * verifier type:    PTR_TO_FUNC.
1155 */
1156#define BPF_PSEUDO_FUNC         4
1157
1158/* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
1159 * offset to another bpf function
1160 */
1161#define BPF_PSEUDO_CALL         1
1162/* when bpf_call->src_reg == BPF_PSEUDO_KFUNC_CALL,
1163 * bpf_call->imm == btf_id of a BTF_KIND_FUNC in the running kernel
1164 */
1165#define BPF_PSEUDO_KFUNC_CALL   2
1166
1167/* flags for BPF_MAP_UPDATE_ELEM command */
1168enum {
1169        BPF_ANY         = 0, /* create new element or update existing */
1170        BPF_NOEXIST     = 1, /* create new element if it didn't exist */
1171        BPF_EXIST       = 2, /* update existing element */
1172        BPF_F_LOCK      = 4, /* spin_lock-ed map_lookup/map_update */
1173};
1174
1175/* flags for BPF_MAP_CREATE command */
1176enum {
1177        BPF_F_NO_PREALLOC       = (1U << 0),
1178/* Instead of having one common LRU list in the
1179 * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
1180 * which can scale and perform better.
1181 * Note, the LRU nodes (including free nodes) cannot be moved
1182 * across different LRU lists.
1183 */
1184        BPF_F_NO_COMMON_LRU     = (1U << 1),
1185/* Specify numa node during map creation */
1186        BPF_F_NUMA_NODE         = (1U << 2),
1187
1188/* Flags for accessing BPF object from syscall side. */
1189        BPF_F_RDONLY            = (1U << 3),
1190        BPF_F_WRONLY            = (1U << 4),
1191
1192/* Flag for stack_map, store build_id+offset instead of pointer */
1193        BPF_F_STACK_BUILD_ID    = (1U << 5),
1194
1195/* Zero-initialize hash function seed. This should only be used for testing. */
1196        BPF_F_ZERO_SEED         = (1U << 6),
1197
1198/* Flags for accessing BPF object from program side. */
1199        BPF_F_RDONLY_PROG       = (1U << 7),
1200        BPF_F_WRONLY_PROG       = (1U << 8),
1201
1202/* Clone map from listener for newly accepted socket */
1203        BPF_F_CLONE             = (1U << 9),
1204
1205/* Enable memory-mapping BPF map */
1206        BPF_F_MMAPABLE          = (1U << 10),
1207
1208/* Share perf_event among processes */
1209        BPF_F_PRESERVE_ELEMS    = (1U << 11),
1210
1211/* Create a map that is suitable to be an inner map with dynamic max entries */
1212        BPF_F_INNER_MAP         = (1U << 12),
1213};
1214
1215/* Flags for BPF_PROG_QUERY. */
1216
1217/* Query effective (directly attached + inherited from ancestor cgroups)
1218 * programs that will be executed for events within a cgroup.
1219 * attach_flags with this flag are returned only for directly attached programs.
1220 */
1221#define BPF_F_QUERY_EFFECTIVE   (1U << 0)
1222
1223/* Flags for BPF_PROG_TEST_RUN */
1224
1225/* If set, run the test on the cpu specified by bpf_attr.test.cpu */
1226#define BPF_F_TEST_RUN_ON_CPU   (1U << 0)
1227
1228/* type for BPF_ENABLE_STATS */
1229enum bpf_stats_type {
1230        /* enabled run_time_ns and run_cnt */
1231        BPF_STATS_RUN_TIME = 0,
1232};
1233
1234enum bpf_stack_build_id_status {
1235        /* user space need an empty entry to identify end of a trace */
1236        BPF_STACK_BUILD_ID_EMPTY = 0,
1237        /* with valid build_id and offset */
1238        BPF_STACK_BUILD_ID_VALID = 1,
1239        /* couldn't get build_id, fallback to ip */
1240        BPF_STACK_BUILD_ID_IP = 2,
1241};
1242
1243#define BPF_BUILD_ID_SIZE 20
1244struct bpf_stack_build_id {
1245        __s32           status;
1246        unsigned char   build_id[BPF_BUILD_ID_SIZE];
1247        union {
1248                __u64   offset;
1249                __u64   ip;
1250        };
1251};
1252
1253#define BPF_OBJ_NAME_LEN 16U
1254
1255union bpf_attr {
1256        struct { /* anonymous struct used by BPF_MAP_CREATE command */
1257                __u32   map_type;       /* one of enum bpf_map_type */
1258                __u32   key_size;       /* size of key in bytes */
1259                __u32   value_size;     /* size of value in bytes */
1260                __u32   max_entries;    /* max number of entries in a map */
1261                __u32   map_flags;      /* BPF_MAP_CREATE related
1262                                         * flags defined above.
1263                                         */
1264                __u32   inner_map_fd;   /* fd pointing to the inner map */
1265                __u32   numa_node;      /* numa node (effective only if
1266                                         * BPF_F_NUMA_NODE is set).
1267                                         */
1268                char    map_name[BPF_OBJ_NAME_LEN];
1269                __u32   map_ifindex;    /* ifindex of netdev to create on */
1270                __u32   btf_fd;         /* fd pointing to a BTF type data */
1271                __u32   btf_key_type_id;        /* BTF type_id of the key */
1272                __u32   btf_value_type_id;      /* BTF type_id of the value */
1273                __u32   btf_vmlinux_value_type_id;/* BTF type_id of a kernel-
1274                                                   * struct stored as the
1275                                                   * map value
1276                                                   */
1277        };
1278
1279        struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
1280                __u32           map_fd;
1281                __aligned_u64   key;
1282                union {
1283                        __aligned_u64 value;
1284                        __aligned_u64 next_key;
1285                };
1286                __u64           flags;
1287        };
1288
1289        struct { /* struct used by BPF_MAP_*_BATCH commands */
1290                __aligned_u64   in_batch;       /* start batch,
1291                                                 * NULL to start from beginning
1292                                                 */
1293                __aligned_u64   out_batch;      /* output: next start batch */
1294                __aligned_u64   keys;
1295                __aligned_u64   values;
1296                __u32           count;          /* input/output:
1297                                                 * input: # of key/value
1298                                                 * elements
1299                                                 * output: # of filled elements
1300                                                 */
1301                __u32           map_fd;
1302                __u64           elem_flags;
1303                __u64           flags;
1304        } batch;
1305
1306        struct { /* anonymous struct used by BPF_PROG_LOAD command */
1307                __u32           prog_type;      /* one of enum bpf_prog_type */
1308                __u32           insn_cnt;
1309                __aligned_u64   insns;
1310                __aligned_u64   license;
1311                __u32           log_level;      /* verbosity level of verifier */
1312                __u32           log_size;       /* size of user buffer */
1313                __aligned_u64   log_buf;        /* user supplied buffer */
1314                __u32           kern_version;   /* not used */
1315                __u32           prog_flags;
1316                char            prog_name[BPF_OBJ_NAME_LEN];
1317                __u32           prog_ifindex;   /* ifindex of netdev to prep for */
1318                /* For some prog types expected attach type must be known at
1319                 * load time to verify attach type specific parts of prog
1320                 * (context accesses, allowed helpers, etc).
1321                 */
1322                __u32           expected_attach_type;
1323                __u32           prog_btf_fd;    /* fd pointing to BTF type data */
1324                __u32           func_info_rec_size;     /* userspace bpf_func_info size */
1325                __aligned_u64   func_info;      /* func info */
1326                __u32           func_info_cnt;  /* number of bpf_func_info records */
1327                __u32           line_info_rec_size;     /* userspace bpf_line_info size */
1328                __aligned_u64   line_info;      /* line info */
1329                __u32           line_info_cnt;  /* number of bpf_line_info records */
1330                __u32           attach_btf_id;  /* in-kernel BTF type id to attach to */
1331                union {
1332                        /* valid prog_fd to attach to bpf prog */
1333                        __u32           attach_prog_fd;
1334                        /* or valid module BTF object fd or 0 to attach to vmlinux */
1335                        __u32           attach_btf_obj_fd;
1336                };
1337                __u32           :32;            /* pad */
1338                __aligned_u64   fd_array;       /* array of FDs */
1339        };
1340
1341        struct { /* anonymous struct used by BPF_OBJ_* commands */
1342                __aligned_u64   pathname;
1343                __u32           bpf_fd;
1344                __u32           file_flags;
1345        };
1346
1347        struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
1348                __u32           target_fd;      /* container object to attach to */
1349                __u32           attach_bpf_fd;  /* eBPF program to attach */
1350                __u32           attach_type;
1351                __u32           attach_flags;
1352                __u32           replace_bpf_fd; /* previously attached eBPF
1353                                                 * program to replace if
1354                                                 * BPF_F_REPLACE is used
1355                                                 */
1356        };
1357
1358        struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
1359                __u32           prog_fd;
1360                __u32           retval;
1361                __u32           data_size_in;   /* input: len of data_in */
1362                __u32           data_size_out;  /* input/output: len of data_out
1363                                                 *   returns ENOSPC if data_out
1364                                                 *   is too small.
1365                                                 */
1366                __aligned_u64   data_in;
1367                __aligned_u64   data_out;
1368                __u32           repeat;
1369                __u32           duration;
1370                __u32           ctx_size_in;    /* input: len of ctx_in */
1371                __u32           ctx_size_out;   /* input/output: len of ctx_out
1372                                                 *   returns ENOSPC if ctx_out
1373                                                 *   is too small.
1374                                                 */
1375                __aligned_u64   ctx_in;
1376                __aligned_u64   ctx_out;
1377                __u32           flags;
1378                __u32           cpu;
1379        } test;
1380
1381        struct { /* anonymous struct used by BPF_*_GET_*_ID */
1382                union {
1383                        __u32           start_id;
1384                        __u32           prog_id;
1385                        __u32           map_id;
1386                        __u32           btf_id;
1387                        __u32           link_id;
1388                };
1389                __u32           next_id;
1390                __u32           open_flags;
1391        };
1392
1393        struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
1394                __u32           bpf_fd;
1395                __u32           info_len;
1396                __aligned_u64   info;
1397        } info;
1398
1399        struct { /* anonymous struct used by BPF_PROG_QUERY command */
1400                __u32           target_fd;      /* container object to query */
1401                __u32           attach_type;
1402                __u32           query_flags;
1403                __u32           attach_flags;
1404                __aligned_u64   prog_ids;
1405                __u32           prog_cnt;
1406        } query;
1407
1408        struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
1409                __u64 name;
1410                __u32 prog_fd;
1411        } raw_tracepoint;
1412
1413        struct { /* anonymous struct for BPF_BTF_LOAD */
1414                __aligned_u64   btf;
1415                __aligned_u64   btf_log_buf;
1416                __u32           btf_size;
1417                __u32           btf_log_size;
1418                __u32           btf_log_level;
1419        };
1420
1421        struct {
1422                __u32           pid;            /* input: pid */
1423                __u32           fd;             /* input: fd */
1424                __u32           flags;          /* input: flags */
1425                __u32           buf_len;        /* input/output: buf len */
1426                __aligned_u64   buf;            /* input/output:
1427                                                 *   tp_name for tracepoint
1428                                                 *   symbol for kprobe
1429                                                 *   filename for uprobe
1430                                                 */
1431                __u32           prog_id;        /* output: prod_id */
1432                __u32           fd_type;        /* output: BPF_FD_TYPE_* */
1433                __u64           probe_offset;   /* output: probe_offset */
1434                __u64           probe_addr;     /* output: probe_addr */
1435        } task_fd_query;
1436
1437        struct { /* struct used by BPF_LINK_CREATE command */
1438                __u32           prog_fd;        /* eBPF program to attach */
1439                union {
1440                        __u32           target_fd;      /* object to attach to */
1441                        __u32           target_ifindex; /* target ifindex */
1442                };
1443                __u32           attach_type;    /* attach type */
1444                __u32           flags;          /* extra flags */
1445                union {
1446                        __u32           target_btf_id;  /* btf_id of target to attach to */
1447                        struct {
1448                                __aligned_u64   iter_info;      /* extra bpf_iter_link_info */
1449                                __u32           iter_info_len;  /* iter_info length */
1450                        };
1451                        struct {
1452                                /* black box user-provided value passed through
1453                                 * to BPF program at the execution time and
1454                                 * accessible through bpf_get_attach_cookie() BPF helper
1455                                 */
1456                                __u64           bpf_cookie;
1457                        } perf_event;
1458                };
1459        } link_create;
1460
1461        struct { /* struct used by BPF_LINK_UPDATE command */
1462                __u32           link_fd;        /* link fd */
1463                /* new program fd to update link with */
1464                __u32           new_prog_fd;
1465                __u32           flags;          /* extra flags */
1466                /* expected link's program fd; is specified only if
1467                 * BPF_F_REPLACE flag is set in flags */
1468                __u32           old_prog_fd;
1469        } link_update;
1470
1471        struct {
1472                __u32           link_fd;
1473        } link_detach;
1474
1475        struct { /* struct used by BPF_ENABLE_STATS command */
1476                __u32           type;
1477        } enable_stats;
1478
1479        struct { /* struct used by BPF_ITER_CREATE command */
1480                __u32           link_fd;
1481                __u32           flags;
1482        } iter_create;
1483
1484        struct { /* struct used by BPF_PROG_BIND_MAP command */
1485                __u32           prog_fd;
1486                __u32           map_fd;
1487                __u32           flags;          /* extra flags */
1488        } prog_bind_map;
1489
1490} __attribute__((aligned(8)));
1491
1492/* The description below is an attempt at providing documentation to eBPF
1493 * developers about the multiple available eBPF helper functions. It can be
1494 * parsed and used to produce a manual page. The workflow is the following,
1495 * and requires the rst2man utility:
1496 *
1497 *     $ ./scripts/bpf_doc.py \
1498 *             --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
1499 *     $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
1500 *     $ man /tmp/bpf-helpers.7
1501 *
1502 * Note that in order to produce this external documentation, some RST
1503 * formatting is used in the descriptions to get "bold" and "italics" in
1504 * manual pages. Also note that the few trailing white spaces are
1505 * intentional, removing them would break paragraphs for rst2man.
1506 *
1507 * Start of BPF helper function descriptions:
1508 *
1509 * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
1510 *      Description
1511 *              Perform a lookup in *map* for an entry associated to *key*.
1512 *      Return
1513 *              Map value associated to *key*, or **NULL** if no entry was
1514 *              found.
1515 *
1516 * long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
1517 *      Description
1518 *              Add or update the value of the entry associated to *key* in
1519 *              *map* with *value*. *flags* is one of:
1520 *
1521 *              **BPF_NOEXIST**
1522 *                      The entry for *key* must not exist in the map.
1523 *              **BPF_EXIST**
1524 *                      The entry for *key* must already exist in the map.
1525 *              **BPF_ANY**
1526 *                      No condition on the existence of the entry for *key*.
1527 *
1528 *              Flag value **BPF_NOEXIST** cannot be used for maps of types
1529 *              **BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY**  (all
1530 *              elements always exist), the helper would return an error.
1531 *      Return
1532 *              0 on success, or a negative error in case of failure.
1533 *
1534 * long bpf_map_delete_elem(struct bpf_map *map, const void *key)
1535 *      Description
1536 *              Delete entry with *key* from *map*.
1537 *      Return
1538 *              0 on success, or a negative error in case of failure.
1539 *
1540 * long bpf_probe_read(void *dst, u32 size, const void *unsafe_ptr)
1541 *      Description
1542 *              For tracing programs, safely attempt to read *size* bytes from
1543 *              kernel space address *unsafe_ptr* and store the data in *dst*.
1544 *
1545 *              Generally, use **bpf_probe_read_user**\ () or
1546 *              **bpf_probe_read_kernel**\ () instead.
1547 *      Return
1548 *              0 on success, or a negative error in case of failure.
1549 *
1550 * u64 bpf_ktime_get_ns(void)
1551 *      Description
1552 *              Return the time elapsed since system boot, in nanoseconds.
1553 *              Does not include time the system was suspended.
1554 *              See: **clock_gettime**\ (**CLOCK_MONOTONIC**)
1555 *      Return
1556 *              Current *ktime*.
1557 *
1558 * long bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
1559 *      Description
1560 *              This helper is a "printk()-like" facility for debugging. It
1561 *              prints a message defined by format *fmt* (of size *fmt_size*)
1562 *              to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
1563 *              available. It can take up to three additional **u64**
1564 *              arguments (as an eBPF helpers, the total number of arguments is
1565 *              limited to five).
1566 *
1567 *              Each time the helper is called, it appends a line to the trace.
1568 *              Lines are discarded while *\/sys/kernel/debug/tracing/trace* is
1569 *              open, use *\/sys/kernel/debug/tracing/trace_pipe* to avoid this.
1570 *              The format of the trace is customizable, and the exact output
1571 *              one will get depends on the options set in
1572 *              *\/sys/kernel/debug/tracing/trace_options* (see also the
1573 *              *README* file under the same directory). However, it usually
1574 *              defaults to something like:
1575 *
1576 *              ::
1577 *
1578 *                      telnet-470   [001] .N.. 419421.045894: 0x00000001: <formatted msg>
1579 *
1580 *              In the above:
1581 *
1582 *                      * ``telnet`` is the name of the current task.
1583 *                      * ``470`` is the PID of the current task.
1584 *                      * ``001`` is the CPU number on which the task is
1585 *                        running.
1586 *                      * In ``.N..``, each character refers to a set of
1587 *                        options (whether irqs are enabled, scheduling
1588 *                        options, whether hard/softirqs are running, level of
1589 *                        preempt_disabled respectively). **N** means that
1590 *                        **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
1591 *                        are set.
1592 *                      * ``419421.045894`` is a timestamp.
1593 *                      * ``0x00000001`` is a fake value used by BPF for the
1594 *                        instruction pointer register.
1595 *                      * ``<formatted msg>`` is the message formatted with
1596 *                        *fmt*.
1597 *
1598 *              The conversion specifiers supported by *fmt* are similar, but
1599 *              more limited than for printk(). They are **%d**, **%i**,
1600 *              **%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
1601 *              **%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
1602 *              of field, padding with zeroes, etc.) is available, and the
1603 *              helper will return **-EINVAL** (but print nothing) if it
1604 *              encounters an unknown specifier.
1605 *
1606 *              Also, note that **bpf_trace_printk**\ () is slow, and should
1607 *              only be used for debugging purposes. For this reason, a notice
1608 *              block (spanning several lines) is printed to kernel logs and
1609 *              states that the helper should not be used "for production use"
1610 *              the first time this helper is used (or more precisely, when
1611 *              **trace_printk**\ () buffers are allocated). For passing values
1612 *              to user space, perf events should be preferred.
1613 *      Return
1614 *              The number of bytes written to the buffer, or a negative error
1615 *              in case of failure.
1616 *
1617 * u32 bpf_get_prandom_u32(void)
1618 *      Description
1619 *              Get a pseudo-random number.
1620 *
1621 *              From a security point of view, this helper uses its own
1622 *              pseudo-random internal state, and cannot be used to infer the
1623 *              seed of other random functions in the kernel. However, it is
1624 *              essential to note that the generator used by the helper is not
1625 *              cryptographically secure.
1626 *      Return
1627 *              A random 32-bit unsigned value.
1628 *
1629 * u32 bpf_get_smp_processor_id(void)
1630 *      Description
1631 *              Get the SMP (symmetric multiprocessing) processor id. Note that
1632 *              all programs run with preemption disabled, which means that the
1633 *              SMP processor id is stable during all the execution of the
1634 *              program.
1635 *      Return
1636 *              The SMP id of the processor running the program.
1637 *
1638 * long bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
1639 *      Description
1640 *              Store *len* bytes from address *from* into the packet
1641 *              associated to *skb*, at *offset*. *flags* are a combination of
1642 *              **BPF_F_RECOMPUTE_CSUM** (automatically recompute the
1643 *              checksum for the packet after storing the bytes) and
1644 *              **BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
1645 *              **->swhash** and *skb*\ **->l4hash** to 0).
1646 *
1647 *              A call to this helper is susceptible to change the underlying
1648 *              packet buffer. Therefore, at load time, all checks on pointers
1649 *              previously done by the verifier are invalidated and must be
1650 *              performed again, if the helper is used in combination with
1651 *              direct packet access.
1652 *      Return
1653 *              0 on success, or a negative error in case of failure.
1654 *
1655 * long bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
1656 *      Description
1657 *              Recompute the layer 3 (e.g. IP) checksum for the packet
1658 *              associated to *skb*. Computation is incremental, so the helper
1659 *              must know the former value of the header field that was
1660 *              modified (*from*), the new value of this field (*to*), and the
1661 *              number of bytes (2 or 4) for this field, stored in *size*.
1662 *              Alternatively, it is possible to store the difference between
1663 *              the previous and the new values of the header field in *to*, by
1664 *              setting *from* and *size* to 0. For both methods, *offset*
1665 *              indicates the location of the IP checksum within the packet.
1666 *
1667 *              This helper works in combination with **bpf_csum_diff**\ (),
1668 *              which does not update the checksum in-place, but offers more
1669 *              flexibility and can handle sizes larger than 2 or 4 for the
1670 *              checksum to update.
1671 *
1672 *              A call to this helper is susceptible to change the underlying
1673 *              packet buffer. Therefore, at load time, all checks on pointers
1674 *              previously done by the verifier are invalidated and must be
1675 *              performed again, if the helper is used in combination with
1676 *              direct packet access.
1677 *      Return
1678 *              0 on success, or a negative error in case of failure.
1679 *
1680 * long bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
1681 *      Description
1682 *              Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
1683 *              packet associated to *skb*. Computation is incremental, so the
1684 *              helper must know the former value of the header field that was
1685 *              modified (*from*), the new value of this field (*to*), and the
1686 *              number of bytes (2 or 4) for this field, stored on the lowest
1687 *              four bits of *flags*. Alternatively, it is possible to store
1688 *              the difference between the previous and the new values of the
1689 *              header field in *to*, by setting *from* and the four lowest
1690 *              bits of *flags* to 0. For both methods, *offset* indicates the
1691 *              location of the IP checksum within the packet. In addition to
1692 *              the size of the field, *flags* can be added (bitwise OR) actual
1693 *              flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
1694 *              untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
1695 *              for updates resulting in a null checksum the value is set to
1696 *              **CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
1697 *              the checksum is to be computed against a pseudo-header.
1698 *
1699 *              This helper works in combination with **bpf_csum_diff**\ (),
1700 *              which does not update the checksum in-place, but offers more
1701 *              flexibility and can handle sizes larger than 2 or 4 for the
1702 *              checksum to update.
1703 *
1704 *              A call to this helper is susceptible to change the underlying
1705 *              packet buffer. Therefore, at load time, all checks on pointers
1706 *              previously done by the verifier are invalidated and must be
1707 *              performed again, if the helper is used in combination with
1708 *              direct packet access.
1709 *      Return
1710 *              0 on success, or a negative error in case of failure.
1711 *
1712 * long bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
1713 *      Description
1714 *              This special helper is used to trigger a "tail call", or in
1715 *              other words, to jump into another eBPF program. The same stack
1716 *              frame is used (but values on stack and in registers for the
1717 *              caller are not accessible to the callee). This mechanism allows
1718 *              for program chaining, either for raising the maximum number of
1719 *              available eBPF instructions, or to execute given programs in
1720 *              conditional blocks. For security reasons, there is an upper
1721 *              limit to the number of successive tail calls that can be
1722 *              performed.
1723 *
1724 *              Upon call of this helper, the program attempts to jump into a
1725 *              program referenced at index *index* in *prog_array_map*, a
1726 *              special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
1727 *              *ctx*, a pointer to the context.
1728 *
1729 *              If the call succeeds, the kernel immediately runs the first
1730 *              instruction of the new program. This is not a function call,
1731 *              and it never returns to the previous program. If the call
1732 *              fails, then the helper has no effect, and the caller continues
1733 *              to run its subsequent instructions. A call can fail if the
1734 *              destination program for the jump does not exist (i.e. *index*
1735 *              is superior to the number of entries in *prog_array_map*), or
1736 *              if the maximum number of tail calls has been reached for this
1737 *              chain of programs. This limit is defined in the kernel by the
1738 *              macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
1739 *              which is currently set to 32.
1740 *      Return
1741 *              0 on success, or a negative error in case of failure.
1742 *
1743 * long bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
1744 *      Description
1745 *              Clone and redirect the packet associated to *skb* to another
1746 *              net device of index *ifindex*. Both ingress and egress
1747 *              interfaces can be used for redirection. The **BPF_F_INGRESS**
1748 *              value in *flags* is used to make the distinction (ingress path
1749 *              is selected if the flag is present, egress path otherwise).
1750 *              This is the only flag supported for now.
1751 *
1752 *              In comparison with **bpf_redirect**\ () helper,
1753 *              **bpf_clone_redirect**\ () has the associated cost of
1754 *              duplicating the packet buffer, but this can be executed out of
1755 *              the eBPF program. Conversely, **bpf_redirect**\ () is more
1756 *              efficient, but it is handled through an action code where the
1757 *              redirection happens only after the eBPF program has returned.
1758 *
1759 *              A call to this helper is susceptible to change the underlying
1760 *              packet buffer. Therefore, at load time, all checks on pointers
1761 *              previously done by the verifier are invalidated and must be
1762 *              performed again, if the helper is used in combination with
1763 *              direct packet access.
1764 *      Return
1765 *              0 on success, or a negative error in case of failure.
1766 *
1767 * u64 bpf_get_current_pid_tgid(void)
1768 *      Return
1769 *              A 64-bit integer containing the current tgid and pid, and
1770 *              created as such:
1771 *              *current_task*\ **->tgid << 32 \|**
1772 *              *current_task*\ **->pid**.
1773 *
1774 * u64 bpf_get_current_uid_gid(void)
1775 *      Return
1776 *              A 64-bit integer containing the current GID and UID, and
1777 *              created as such: *current_gid* **<< 32 \|** *current_uid*.
1778 *
1779 * long bpf_get_current_comm(void *buf, u32 size_of_buf)
1780 *      Description
1781 *              Copy the **comm** attribute of the current task into *buf* of
1782 *              *size_of_buf*. The **comm** attribute contains the name of
1783 *              the executable (excluding the path) for the current task. The
1784 *              *size_of_buf* must be strictly positive. On success, the
1785 *              helper makes sure that the *buf* is NUL-terminated. On failure,
1786 *              it is filled with zeroes.
1787 *      Return
1788 *              0 on success, or a negative error in case of failure.
1789 *
1790 * u32 bpf_get_cgroup_classid(struct sk_buff *skb)
1791 *      Description
1792 *              Retrieve the classid for the current task, i.e. for the net_cls
1793 *              cgroup to which *skb* belongs.
1794 *
1795 *              This helper can be used on TC egress path, but not on ingress.
1796 *
1797 *              The net_cls cgroup provides an interface to tag network packets
1798 *              based on a user-provided identifier for all traffic coming from
1799 *              the tasks belonging to the related cgroup. See also the related
1800 *              kernel documentation, available from the Linux sources in file
1801 *              *Documentation/admin-guide/cgroup-v1/net_cls.rst*.
1802 *
1803 *              The Linux kernel has two versions for cgroups: there are
1804 *              cgroups v1 and cgroups v2. Both are available to users, who can
1805 *              use a mixture of them, but note that the net_cls cgroup is for
1806 *              cgroup v1 only. This makes it incompatible with BPF programs
1807 *              run on cgroups, which is a cgroup-v2-only feature (a socket can
1808 *              only hold data for one version of cgroups at a time).
1809 *
1810 *              This helper is only available is the kernel was compiled with
1811 *              the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
1812 *              "**y**" or to "**m**".
1813 *      Return
1814 *              The classid, or 0 for the default unconfigured classid.
1815 *
1816 * long bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
1817 *      Description
1818 *              Push a *vlan_tci* (VLAN tag control information) of protocol
1819 *              *vlan_proto* to the packet associated to *skb*, then update
1820 *              the checksum. Note that if *vlan_proto* is different from
1821 *              **ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
1822 *              be **ETH_P_8021Q**.
1823 *
1824 *              A call to this helper is susceptible to change the underlying
1825 *              packet buffer. Therefore, at load time, all checks on pointers
1826 *              previously done by the verifier are invalidated and must be
1827 *              performed again, if the helper is used in combination with
1828 *              direct packet access.
1829 *      Return
1830 *              0 on success, or a negative error in case of failure.
1831 *
1832 * long bpf_skb_vlan_pop(struct sk_buff *skb)
1833 *      Description
1834 *              Pop a VLAN header from the packet associated to *skb*.
1835 *
1836 *              A call to this helper is susceptible to change the underlying
1837 *              packet buffer. Therefore, at load time, all checks on pointers
1838 *              previously done by the verifier are invalidated and must be
1839 *              performed again, if the helper is used in combination with
1840 *              direct packet access.
1841 *      Return
1842 *              0 on success, or a negative error in case of failure.
1843 *
1844 * long bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
1845 *      Description
1846 *              Get tunnel metadata. This helper takes a pointer *key* to an
1847 *              empty **struct bpf_tunnel_key** of **size**, that will be
1848 *              filled with tunnel metadata for the packet associated to *skb*.
1849 *              The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
1850 *              indicates that the tunnel is based on IPv6 protocol instead of
1851 *              IPv4.
1852 *
1853 *              The **struct bpf_tunnel_key** is an object that generalizes the
1854 *              principal parameters used by various tunneling protocols into a
1855 *              single struct. This way, it can be used to easily make a
1856 *              decision based on the contents of the encapsulation header,
1857 *              "summarized" in this struct. In particular, it holds the IP
1858 *              address of the remote end (IPv4 or IPv6, depending on the case)
1859 *              in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
1860 *              this struct exposes the *key*\ **->tunnel_id**, which is
1861 *              generally mapped to a VNI (Virtual Network Identifier), making
1862 *              it programmable together with the **bpf_skb_set_tunnel_key**\
1863 *              () helper.
1864 *
1865 *              Let's imagine that the following code is part of a program
1866 *              attached to the TC ingress interface, on one end of a GRE
1867 *              tunnel, and is supposed to filter out all messages coming from
1868 *              remote ends with IPv4 address other than 10.0.0.1:
1869 *
1870 *              ::
1871 *
1872 *                      int ret;
1873 *                      struct bpf_tunnel_key key = {};
1874 *
1875 *                      ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
1876 *                      if (ret < 0)
1877 *                              return TC_ACT_SHOT;     // drop packet
1878 *
1879 *                      if (key.remote_ipv4 != 0x0a000001)
1880 *                              return TC_ACT_SHOT;     // drop packet
1881 *
1882 *                      return TC_ACT_OK;               // accept packet
1883 *
1884 *              This interface can also be used with all encapsulation devices
1885 *              that can operate in "collect metadata" mode: instead of having
1886 *              one network device per specific configuration, the "collect
1887 *              metadata" mode only requires a single device where the
1888 *              configuration can be extracted from this helper.
1889 *
1890 *              This can be used together with various tunnels such as VXLan,
1891 *              Geneve, GRE or IP in IP (IPIP).
1892 *      Return
1893 *              0 on success, or a negative error in case of failure.
1894 *
1895 * long bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
1896 *      Description
1897 *              Populate tunnel metadata for packet associated to *skb.* The
1898 *              tunnel metadata is set to the contents of *key*, of *size*. The
1899 *              *flags* can be set to a combination of the following values:
1900 *
1901 *              **BPF_F_TUNINFO_IPV6**
1902 *                      Indicate that the tunnel is based on IPv6 protocol
1903 *                      instead of IPv4.
1904 *              **BPF_F_ZERO_CSUM_TX**
1905 *                      For IPv4 packets, add a flag to tunnel metadata
1906 *                      indicating that checksum computation should be skipped
1907 *                      and checksum set to zeroes.
1908 *              **BPF_F_DONT_FRAGMENT**
1909 *                      Add a flag to tunnel metadata indicating that the
1910 *                      packet should not be fragmented.
1911 *              **BPF_F_SEQ_NUMBER**
1912 *                      Add a flag to tunnel metadata indicating that a
1913 *                      sequence number should be added to tunnel header before
1914 *                      sending the packet. This flag was added for GRE
1915 *                      encapsulation, but might be used with other protocols
1916 *                      as well in the future.
1917 *
1918 *              Here is a typical usage on the transmit path:
1919 *
1920 *              ::
1921 *
1922 *                      struct bpf_tunnel_key key;
1923 *                           populate key ...
1924 *                      bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
1925 *                      bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
1926 *
1927 *              See also the description of the **bpf_skb_get_tunnel_key**\ ()
1928 *              helper for additional information.
1929 *      Return
1930 *              0 on success, or a negative error in case of failure.
1931 *
1932 * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
1933 *      Description
1934 *              Read the value of a perf event counter. This helper relies on a
1935 *              *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
1936 *              the perf event counter is selected when *map* is updated with
1937 *              perf event file descriptors. The *map* is an array whose size
1938 *              is the number of available CPUs, and each cell contains a value
1939 *              relative to one CPU. The value to retrieve is indicated by
1940 *              *flags*, that contains the index of the CPU to look up, masked
1941 *              with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
1942 *              **BPF_F_CURRENT_CPU** to indicate that the value for the
1943 *              current CPU should be retrieved.
1944 *
1945 *              Note that before Linux 4.13, only hardware perf event can be
1946 *              retrieved.
1947 *
1948 *              Also, be aware that the newer helper
1949 *              **bpf_perf_event_read_value**\ () is recommended over
1950 *              **bpf_perf_event_read**\ () in general. The latter has some ABI
1951 *              quirks where error and counter value are used as a return code
1952 *              (which is wrong to do since ranges may overlap). This issue is
1953 *              fixed with **bpf_perf_event_read_value**\ (), which at the same
1954 *              time provides more features over the **bpf_perf_event_read**\
1955 *              () interface. Please refer to the description of
1956 *              **bpf_perf_event_read_value**\ () for details.
1957 *      Return
1958 *              The value of the perf event counter read from the map, or a
1959 *              negative error code in case of failure.
1960 *
1961 * long bpf_redirect(u32 ifindex, u64 flags)
1962 *      Description
1963 *              Redirect the packet to another net device of index *ifindex*.
1964 *              This helper is somewhat similar to **bpf_clone_redirect**\
1965 *              (), except that the packet is not cloned, which provides
1966 *              increased performance.
1967 *
1968 *              Except for XDP, both ingress and egress interfaces can be used
1969 *              for redirection. The **BPF_F_INGRESS** value in *flags* is used
1970 *              to make the distinction (ingress path is selected if the flag
1971 *              is present, egress path otherwise). Currently, XDP only
1972 *              supports redirection to the egress interface, and accepts no
1973 *              flag at all.
1974 *
1975 *              The same effect can also be attained with the more generic
1976 *              **bpf_redirect_map**\ (), which uses a BPF map to store the
1977 *              redirect target instead of providing it directly to the helper.
1978 *      Return
1979 *              For XDP, the helper returns **XDP_REDIRECT** on success or
1980 *              **XDP_ABORTED** on error. For other program types, the values
1981 *              are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
1982 *              error.
1983 *
1984 * u32 bpf_get_route_realm(struct sk_buff *skb)
1985 *      Description
1986 *              Retrieve the realm or the route, that is to say the
1987 *              **tclassid** field of the destination for the *skb*. The
1988 *              identifier retrieved is a user-provided tag, similar to the
1989 *              one used with the net_cls cgroup (see description for
1990 *              **bpf_get_cgroup_classid**\ () helper), but here this tag is
1991 *              held by a route (a destination entry), not by a task.
1992 *
1993 *              Retrieving this identifier works with the clsact TC egress hook
1994 *              (see also **tc-bpf(8)**), or alternatively on conventional
1995 *              classful egress qdiscs, but not on TC ingress path. In case of
1996 *              clsact TC egress hook, this has the advantage that, internally,
1997 *              the destination entry has not been dropped yet in the transmit
1998 *              path. Therefore, the destination entry does not need to be
1999 *              artificially held via **netif_keep_dst**\ () for a classful
2000 *              qdisc until the *skb* is freed.
2001 *
2002 *              This helper is available only if the kernel was compiled with
2003 *              **CONFIG_IP_ROUTE_CLASSID** configuration option.
2004 *      Return
2005 *              The realm of the route for the packet associated to *skb*, or 0
2006 *              if none was found.
2007 *
2008 * long bpf_perf_event_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
2009 *      Description
2010 *              Write raw *data* blob into a special BPF perf event held by
2011 *              *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
2012 *              event must have the following attributes: **PERF_SAMPLE_RAW**
2013 *              as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
2014 *              **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
2015 *
2016 *              The *flags* are used to indicate the index in *map* for which
2017 *              the value must be put, masked with **BPF_F_INDEX_MASK**.
2018 *              Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
2019 *              to indicate that the index of the current CPU core should be
2020 *              used.
2021 *
2022 *              The value to write, of *size*, is passed through eBPF stack and
2023 *              pointed by *data*.
2024 *
2025 *              The context of the program *ctx* needs also be passed to the
2026 *              helper.
2027 *
2028 *              On user space, a program willing to read the values needs to
2029 *              call **perf_event_open**\ () on the perf event (either for
2030 *              one or for all CPUs) and to store the file descriptor into the
2031 *              *map*. This must be done before the eBPF program can send data
2032 *              into it. An example is available in file
2033 *              *samples/bpf/trace_output_user.c* in the Linux kernel source
2034 *              tree (the eBPF program counterpart is in
2035 *              *samples/bpf/trace_output_kern.c*).
2036 *
2037 *              **bpf_perf_event_output**\ () achieves better performance
2038 *              than **bpf_trace_printk**\ () for sharing data with user
2039 *              space, and is much better suitable for streaming data from eBPF
2040 *              programs.
2041 *
2042 *              Note that this helper is not restricted to tracing use cases
2043 *              and can be used with programs attached to TC or XDP as well,
2044 *              where it allows for passing data to user space listeners. Data
2045 *              can be:
2046 *
2047 *              * Only custom structs,
2048 *              * Only the packet payload, or
2049 *              * A combination of both.
2050 *      Return
2051 *              0 on success, or a negative error in case of failure.
2052 *
2053 * long bpf_skb_load_bytes(const void *skb, u32 offset, void *to, u32 len)
2054 *      Description
2055 *              This helper was provided as an easy way to load data from a
2056 *              packet. It can be used to load *len* bytes from *offset* from
2057 *              the packet associated to *skb*, into the buffer pointed by
2058 *              *to*.
2059 *
2060 *              Since Linux 4.7, usage of this helper has mostly been replaced
2061 *              by "direct packet access", enabling packet data to be
2062 *              manipulated with *skb*\ **->data** and *skb*\ **->data_end**
2063 *              pointing respectively to the first byte of packet data and to
2064 *              the byte after the last byte of packet data. However, it
2065 *              remains useful if one wishes to read large quantities of data
2066 *              at once from a packet into the eBPF stack.
2067 *      Return
2068 *              0 on success, or a negative error in case of failure.
2069 *
2070 * long bpf_get_stackid(void *ctx, struct bpf_map *map, u64 flags)
2071 *      Description
2072 *              Walk a user or a kernel stack and return its id. To achieve
2073 *              this, the helper needs *ctx*, which is a pointer to the context
2074 *              on which the tracing program is executed, and a pointer to a
2075 *              *map* of type **BPF_MAP_TYPE_STACK_TRACE**.
2076 *
2077 *              The last argument, *flags*, holds the number of stack frames to
2078 *              skip (from 0 to 255), masked with
2079 *              **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
2080 *              a combination of the following flags:
2081 *
2082 *              **BPF_F_USER_STACK**
2083 *                      Collect a user space stack instead of a kernel stack.
2084 *              **BPF_F_FAST_STACK_CMP**
2085 *                      Compare stacks by hash only.
2086 *              **BPF_F_REUSE_STACKID**
2087 *                      If two different stacks hash into the same *stackid*,
2088 *                      discard the old one.
2089 *
2090 *              The stack id retrieved is a 32 bit long integer handle which
2091 *              can be further combined with other data (including other stack
2092 *              ids) and used as a key into maps. This can be useful for
2093 *              generating a variety of graphs (such as flame graphs or off-cpu
2094 *              graphs).
2095 *
2096 *              For walking a stack, this helper is an improvement over
2097 *              **bpf_probe_read**\ (), which can be used with unrolled loops
2098 *              but is not efficient and consumes a lot of eBPF instructions.
2099 *              Instead, **bpf_get_stackid**\ () can collect up to
2100 *              **PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
2101 *              this limit can be controlled with the **sysctl** program, and
2102 *              that it should be manually increased in order to profile long
2103 *              user stacks (such as stacks for Java programs). To do so, use:
2104 *
2105 *              ::
2106 *
2107 *                      # sysctl kernel.perf_event_max_stack=<new value>
2108 *      Return
2109 *              The positive or null stack id on success, or a negative error
2110 *              in case of failure.
2111 *
2112 * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
2113 *      Description
2114 *              Compute a checksum difference, from the raw buffer pointed by
2115 *              *from*, of length *from_size* (that must be a multiple of 4),
2116 *              towards the raw buffer pointed by *to*, of size *to_size*
2117 *              (same remark). An optional *seed* can be added to the value
2118 *              (this can be cascaded, the seed may come from a previous call
2119 *              to the helper).
2120 *
2121 *              This is flexible enough to be used in several ways:
2122 *
2123 *              * With *from_size* == 0, *to_size* > 0 and *seed* set to
2124 *                checksum, it can be used when pushing new data.
2125 *              * With *from_size* > 0, *to_size* == 0 and *seed* set to
2126 *                checksum, it can be used when removing data from a packet.
2127 *              * With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
2128 *                can be used to compute a diff. Note that *from_size* and
2129 *                *to_size* do not need to be equal.
2130 *
2131 *              This helper can be used in combination with
2132 *              **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
2133 *              which one can feed in the difference computed with
2134 *              **bpf_csum_diff**\ ().
2135 *      Return
2136 *              The checksum result, or a negative error code in case of
2137 *              failure.
2138 *
2139 * long bpf_skb_get_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
2140 *      Description
2141 *              Retrieve tunnel options metadata for the packet associated to
2142 *              *skb*, and store the raw tunnel option data to the buffer *opt*
2143 *              of *size*.
2144 *
2145 *              This helper can be used with encapsulation devices that can
2146 *              operate in "collect metadata" mode (please refer to the related
2147 *              note in the description of **bpf_skb_get_tunnel_key**\ () for
2148 *              more details). A particular example where this can be used is
2149 *              in combination with the Geneve encapsulation protocol, where it
2150 *              allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
2151 *              and retrieving arbitrary TLVs (Type-Length-Value headers) from
2152 *              the eBPF program. This allows for full customization of these
2153 *              headers.
2154 *      Return
2155 *              The size of the option data retrieved.
2156 *
2157 * long bpf_skb_set_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
2158 *      Description
2159 *              Set tunnel options metadata for the packet associated to *skb*
2160 *              to the option data contained in the raw buffer *opt* of *size*.
2161 *
2162 *              See also the description of the **bpf_skb_get_tunnel_opt**\ ()
2163 *              helper for additional information.
2164 *      Return
2165 *              0 on success, or a negative error in case of failure.
2166 *
2167 * long bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
2168 *      Description
2169 *              Change the protocol of the *skb* to *proto*. Currently
2170 *              supported are transition from IPv4 to IPv6, and from IPv6 to
2171 *              IPv4. The helper takes care of the groundwork for the
2172 *              transition, including resizing the socket buffer. The eBPF
2173 *              program is expected to fill the new headers, if any, via
2174 *              **skb_store_bytes**\ () and to recompute the checksums with
2175 *              **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
2176 *              (). The main case for this helper is to perform NAT64
2177 *              operations out of an eBPF program.
2178 *
2179 *              Internally, the GSO type is marked as dodgy so that headers are
2180 *              checked and segments are recalculated by the GSO/GRO engine.
2181 *              The size for GSO target is adapted as well.
2182 *
2183 *              All values for *flags* are reserved for future usage, and must
2184 *              be left at zero.
2185 *
2186 *              A call to this helper is susceptible to change the underlying
2187 *              packet buffer. Therefore, at load time, all checks on pointers
2188 *              previously done by the verifier are invalidated and must be
2189 *              performed again, if the helper is used in combination with
2190 *              direct packet access.
2191 *      Return
2192 *              0 on success, or a negative error in case of failure.
2193 *
2194 * long bpf_skb_change_type(struct sk_buff *skb, u32 type)
2195 *      Description
2196 *              Change the packet type for the packet associated to *skb*. This
2197 *              comes down to setting *skb*\ **->pkt_type** to *type*, except
2198 *              the eBPF program does not have a write access to *skb*\
2199 *              **->pkt_type** beside this helper. Using a helper here allows
2200 *              for graceful handling of errors.
2201 *
2202 *              The major use case is to change incoming *skb*s to
2203 *              **PACKET_HOST** in a programmatic way instead of having to
2204 *              recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
2205 *              example.
2206 *
2207 *              Note that *type* only allows certain values. At this time, they
2208 *              are:
2209 *
2210 *              **PACKET_HOST**
2211 *                      Packet is for us.
2212 *              **PACKET_BROADCAST**
2213 *                      Send packet to all.
2214 *              **PACKET_MULTICAST**
2215 *                      Send packet to group.
2216 *              **PACKET_OTHERHOST**
2217 *                      Send packet to someone else.
2218 *      Return
2219 *              0 on success, or a negative error in case of failure.
2220 *
2221 * long bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
2222 *      Description
2223 *              Check whether *skb* is a descendant of the cgroup2 held by
2224 *              *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
2225 *      Return
2226 *              The return value depends on the result of the test, and can be:
2227 *
2228 *              * 0, if the *skb* failed the cgroup2 descendant test.
2229 *              * 1, if the *skb* succeeded the cgroup2 descendant test.
2230 *              * A negative error code, if an error occurred.
2231 *
2232 * u32 bpf_get_hash_recalc(struct sk_buff *skb)
2233 *      Description
2234 *              Retrieve the hash of the packet, *skb*\ **->hash**. If it is
2235 *              not set, in particular if the hash was cleared due to mangling,
2236 *              recompute this hash. Later accesses to the hash can be done
2237 *              directly with *skb*\ **->hash**.
2238 *
2239 *              Calling **bpf_set_hash_invalid**\ (), changing a packet
2240 *              prototype with **bpf_skb_change_proto**\ (), or calling
2241 *              **bpf_skb_store_bytes**\ () with the
2242 *              **BPF_F_INVALIDATE_HASH** are actions susceptible to clear
2243 *              the hash and to trigger a new computation for the next call to
2244 *              **bpf_get_hash_recalc**\ ().
2245 *      Return
2246 *              The 32-bit hash.
2247 *
2248 * u64 bpf_get_current_task(void)
2249 *      Return
2250 *              A pointer to the current task struct.
2251 *
2252 * long bpf_probe_write_user(void *dst, const void *src, u32 len)
2253 *      Description
2254 *              Attempt in a safe way to write *len* bytes from the buffer
2255 *              *src* to *dst* in memory. It only works for threads that are in
2256 *              user context, and *dst* must be a valid user space address.
2257 *
2258 *              This helper should not be used to implement any kind of
2259 *              security mechanism because of TOC-TOU attacks, but rather to
2260 *              debug, divert, and manipulate execution of semi-cooperative
2261 *              processes.
2262 *
2263 *              Keep in mind that this feature is meant for experiments, and it
2264 *              has a risk of crashing the system and running programs.
2265 *              Therefore, when an eBPF program using this helper is attached,
2266 *              a warning including PID and process name is printed to kernel
2267 *              logs.
2268 *      Return
2269 *              0 on success, or a negative error in case of failure.
2270 *
2271 * long bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
2272 *      Description
2273 *              Check whether the probe is being run is the context of a given
2274 *              subset of the cgroup2 hierarchy. The cgroup2 to test is held by
2275 *              *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
2276 *      Return
2277 *              The return value depends on the result of the test, and can be:
2278 *
2279 *              * 0, if current task belongs to the cgroup2.
2280 *              * 1, if current task does not belong to the cgroup2.
2281 *              * A negative error code, if an error occurred.
2282 *
2283 * long bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
2284 *      Description
2285 *              Resize (trim or grow) the packet associated to *skb* to the
2286 *              new *len*. The *flags* are reserved for future usage, and must
2287 *              be left at zero.
2288 *
2289 *              The basic idea is that the helper performs the needed work to
2290 *              change the size of the packet, then the eBPF program rewrites
2291 *              the rest via helpers like **bpf_skb_store_bytes**\ (),
2292 *              **bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
2293 *              and others. This helper is a slow path utility intended for
2294 *              replies with control messages. And because it is targeted for
2295 *              slow path, the helper itself can afford to be slow: it
2296 *              implicitly linearizes, unclones and drops offloads from the
2297 *              *skb*.
2298 *
2299 *              A call to this helper is susceptible to change the underlying
2300 *              packet buffer. Therefore, at load time, all checks on pointers
2301 *              previously done by the verifier are invalidated and must be
2302 *              performed again, if the helper is used in combination with
2303 *              direct packet access.
2304 *      Return
2305 *              0 on success, or a negative error in case of failure.
2306 *
2307 * long bpf_skb_pull_data(struct sk_buff *skb, u32 len)
2308 *      Description
2309 *              Pull in non-linear data in case the *skb* is non-linear and not
2310 *              all of *len* are part of the linear section. Make *len* bytes
2311 *              from *skb* readable and writable. If a zero value is passed for
2312 *              *len*, then the whole length of the *skb* is pulled.
2313 *
2314 *              This helper is only needed for reading and writing with direct
2315 *              packet access.
2316 *
2317 *              For direct packet access, testing that offsets to access
2318 *              are within packet boundaries (test on *skb*\ **->data_end**) is
2319 *              susceptible to fail if offsets are invalid, or if the requested
2320 *              data is in non-linear parts of the *skb*. On failure the
2321 *              program can just bail out, or in the case of a non-linear
2322 *              buffer, use a helper to make the data available. The
2323 *              **bpf_skb_load_bytes**\ () helper is a first solution to access
2324 *              the data. Another one consists in using **bpf_skb_pull_data**
2325 *              to pull in once the non-linear parts, then retesting and
2326 *              eventually access the data.
2327 *
2328 *              At the same time, this also makes sure the *skb* is uncloned,
2329 *              which is a necessary condition for direct write. As this needs
2330 *              to be an invariant for the write part only, the verifier
2331 *              detects writes and adds a prologue that is calling
2332 *              **bpf_skb_pull_data()** to effectively unclone the *skb* from
2333 *              the very beginning in case it is indeed cloned.
2334 *
2335 *              A call to this helper is susceptible to change the underlying
2336 *              packet buffer. Therefore, at load time, all checks on pointers
2337 *              previously done by the verifier are invalidated and must be
2338 *              performed again, if the helper is used in combination with
2339 *              direct packet access.
2340 *      Return
2341 *              0 on success, or a negative error in case of failure.
2342 *
2343 * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
2344 *      Description
2345 *              Add the checksum *csum* into *skb*\ **->csum** in case the
2346 *              driver has supplied a checksum for the entire packet into that
2347 *              field. Return an error otherwise. This helper is intended to be
2348 *              used in combination with **bpf_csum_diff**\ (), in particular
2349 *              when the checksum needs to be updated after data has been
2350 *              written into the packet through direct packet access.
2351 *      Return
2352 *              The checksum on success, or a negative error code in case of
2353 *              failure.
2354 *
2355 * void bpf_set_hash_invalid(struct sk_buff *skb)
2356 *      Description
2357 *              Invalidate the current *skb*\ **->hash**. It can be used after
2358 *              mangling on headers through direct packet access, in order to
2359 *              indicate that the hash is outdated and to trigger a
2360 *              recalculation the next time the kernel tries to access this
2361 *              hash or when the **bpf_get_hash_recalc**\ () helper is called.
2362 *
2363 * long bpf_get_numa_node_id(void)
2364 *      Description
2365 *              Return the id of the current NUMA node. The primary use case
2366 *              for this helper is the selection of sockets for the local NUMA
2367 *              node, when the program is attached to sockets using the
2368 *              **SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
2369 *              but the helper is also available to other eBPF program types,
2370 *              similarly to **bpf_get_smp_processor_id**\ ().
2371 *      Return
2372 *              The id of current NUMA node.
2373 *
2374 * long bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
2375 *      Description
2376 *              Grows headroom of packet associated to *skb* and adjusts the
2377 *              offset of the MAC header accordingly, adding *len* bytes of
2378 *              space. It automatically extends and reallocates memory as
2379 *              required.
2380 *
2381 *              This helper can be used on a layer 3 *skb* to push a MAC header
2382 *              for redirection into a layer 2 device.
2383 *
2384 *              All values for *flags* are reserved for future usage, and must
2385 *              be left at zero.
2386 *
2387 *              A call to this helper is susceptible to change the underlying
2388 *              packet buffer. Therefore, at load time, all checks on pointers
2389 *              previously done by the verifier are invalidated and must be
2390 *              performed again, if the helper is used in combination with
2391 *              direct packet access.
2392 *      Return
2393 *              0 on success, or a negative error in case of failure.
2394 *
2395 * long bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
2396 *      Description
2397 *              Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
2398 *              it is possible to use a negative value for *delta*. This helper
2399 *              can be used to prepare the packet for pushing or popping
2400 *              headers.
2401 *
2402 *              A call to this helper is susceptible to change the underlying
2403 *              packet buffer. Therefore, at load time, all checks on pointers
2404 *              previously done by the verifier are invalidated and must be
2405 *              performed again, if the helper is used in combination with
2406 *              direct packet access.
2407 *      Return
2408 *              0 on success, or a negative error in case of failure.
2409 *
2410 * long bpf_probe_read_str(void *dst, u32 size, const void *unsafe_ptr)
2411 *      Description
2412 *              Copy a NUL terminated string from an unsafe kernel address
2413 *              *unsafe_ptr* to *dst*. See **bpf_probe_read_kernel_str**\ () for
2414 *              more details.
2415 *
2416 *              Generally, use **bpf_probe_read_user_str**\ () or
2417 *              **bpf_probe_read_kernel_str**\ () instead.
2418 *      Return
2419 *              On success, the strictly positive length of the string,
2420 *              including the trailing NUL character. On error, a negative
2421 *              value.
2422 *
2423 * u64 bpf_get_socket_cookie(struct sk_buff *skb)
2424 *      Description
2425 *              If the **struct sk_buff** pointed by *skb* has a known socket,
2426 *              retrieve the cookie (generated by the kernel) of this socket.
2427 *              If no cookie has been set yet, generate a new cookie. Once
2428 *              generated, the socket cookie remains stable for the life of the
2429 *              socket. This helper can be useful for monitoring per socket
2430 *              networking traffic statistics as it provides a global socket
2431 *              identifier that can be assumed unique.
2432 *      Return
2433 *              A 8-byte long unique number on success, or 0 if the socket
2434 *              field is missing inside *skb*.
2435 *
2436 * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
2437 *      Description
2438 *              Equivalent to bpf_get_socket_cookie() helper that accepts
2439 *              *skb*, but gets socket from **struct bpf_sock_addr** context.
2440 *      Return
2441 *              A 8-byte long unique number.
2442 *
2443 * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
2444 *      Description
2445 *              Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
2446 *              *skb*, but gets socket from **struct bpf_sock_ops** context.
2447 *      Return
2448 *              A 8-byte long unique number.
2449 *
2450 * u64 bpf_get_socket_cookie(struct sock *sk)
2451 *      Description
2452 *              Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
2453 *              *sk*, but gets socket from a BTF **struct sock**. This helper
2454 *              also works for sleepable programs.
2455 *      Return
2456 *              A 8-byte long unique number or 0 if *sk* is NULL.
2457 *
2458 * u32 bpf_get_socket_uid(struct sk_buff *skb)
2459 *      Return
2460 *              The owner UID of the socket associated to *skb*. If the socket
2461 *              is **NULL**, or if it is not a full socket (i.e. if it is a
2462 *              time-wait or a request socket instead), **overflowuid** value
2463 *              is returned (note that **overflowuid** might also be the actual
2464 *              UID value for the socket).
2465 *
2466 * long bpf_set_hash(struct sk_buff *skb, u32 hash)
2467 *      Description
2468 *              Set the full hash for *skb* (set the field *skb*\ **->hash**)
2469 *              to value *hash*.
2470 *      Return
2471 *              0
2472 *
2473 * long bpf_setsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
2474 *      Description
2475 *              Emulate a call to **setsockopt()** on the socket associated to
2476 *              *bpf_socket*, which must be a full socket. The *level* at
2477 *              which the option resides and the name *optname* of the option
2478 *              must be specified, see **setsockopt(2)** for more information.
2479 *              The option value of length *optlen* is pointed by *optval*.
2480 *
2481 *              *bpf_socket* should be one of the following:
2482 *
2483 *              * **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
2484 *              * **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
2485 *                and **BPF_CGROUP_INET6_CONNECT**.
2486 *
2487 *              This helper actually implements a subset of **setsockopt()**.
2488 *              It supports the following *level*\ s:
2489 *
2490 *              * **SOL_SOCKET**, which supports the following *optname*\ s:
2491 *                **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
2492 *                **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
2493 *                **SO_BINDTODEVICE**, **SO_KEEPALIVE**.
2494 *              * **IPPROTO_TCP**, which supports the following *optname*\ s:
2495 *                **TCP_CONGESTION**, **TCP_BPF_IW**,
2496 *                **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
2497 *                **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**,
2498 *                **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**.
2499 *              * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
2500 *              * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
2501 *      Return
2502 *              0 on success, or a negative error in case of failure.
2503 *
2504 * long bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
2505 *      Description
2506 *              Grow or shrink the room for data in the packet associated to
2507 *              *skb* by *len_diff*, and according to the selected *mode*.
2508 *
2509 *              By default, the helper will reset any offloaded checksum
2510 *              indicator of the skb to CHECKSUM_NONE. This can be avoided
2511 *              by the following flag:
2512 *
2513 *              * **BPF_F_ADJ_ROOM_NO_CSUM_RESET**: Do not reset offloaded
2514 *                checksum data of the skb to CHECKSUM_NONE.
2515 *
2516 *              There are two supported modes at this time:
2517 *
2518 *              * **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
2519 *                (room space is added or removed below the layer 2 header).
2520 *
2521 *              * **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
2522 *                (room space is added or removed below the layer 3 header).
2523 *
2524 *              The following flags are supported at this time:
2525 *
2526 *              * **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
2527 *                Adjusting mss in this way is not allowed for datagrams.
2528 *
2529 *              * **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**,
2530 *                **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**:
2531 *                Any new space is reserved to hold a tunnel header.
2532 *                Configure skb offsets and other fields accordingly.
2533 *
2534 *              * **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**,
2535 *                **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**:
2536 *                Use with ENCAP_L3 flags to further specify the tunnel type.
2537 *
2538 *              * **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*):
2539 *                Use with ENCAP_L3/L4 flags to further specify the tunnel
2540 *                type; *len* is the length of the inner MAC header.
2541 *
2542 *              * **BPF_F_ADJ_ROOM_ENCAP_L2_ETH**:
2543 *                Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the
2544 *                L2 type as Ethernet.
2545 *
2546 *              A call to this helper is susceptible to change the underlying
2547 *              packet buffer. Therefore, at load time, all checks on pointers
2548 *              previously done by the verifier are invalidated and must be
2549 *              performed again, if the helper is used in combination with
2550 *              direct packet access.
2551 *      Return
2552 *              0 on success, or a negative error in case of failure.
2553 *
2554 * long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
2555 *      Description
2556 *              Redirect the packet to the endpoint referenced by *map* at
2557 *              index *key*. Depending on its type, this *map* can contain
2558 *              references to net devices (for forwarding packets through other
2559 *              ports), or to CPUs (for redirecting XDP frames to another CPU;
2560 *              but this is only implemented for native XDP (with driver
2561 *              support) as of this writing).
2562 *
2563 *              The lower two bits of *flags* are used as the return code if
2564 *              the map lookup fails. This is so that the return value can be
2565 *              one of the XDP program return codes up to **XDP_TX**, as chosen
2566 *              by the caller. The higher bits of *flags* can be set to
2567 *              BPF_F_BROADCAST or BPF_F_EXCLUDE_INGRESS as defined below.
2568 *
2569 *              With BPF_F_BROADCAST the packet will be broadcasted to all the
2570 *              interfaces in the map, with BPF_F_EXCLUDE_INGRESS the ingress
2571 *              interface will be excluded when do broadcasting.
2572 *
2573 *              See also **bpf_redirect**\ (), which only supports redirecting
2574 *              to an ifindex, but doesn't require a map to do so.
2575 *      Return
2576 *              **XDP_REDIRECT** on success, or the value of the two lower bits
2577 *              of the *flags* argument on error.
2578 *
2579 * long bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
2580 *      Description
2581 *              Redirect the packet to the socket referenced by *map* (of type
2582 *              **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
2583 *              egress interfaces can be used for redirection. The
2584 *              **BPF_F_INGRESS** value in *flags* is used to make the
2585 *              distinction (ingress path is selected if the flag is present,
2586 *              egress path otherwise). This is the only flag supported for now.
2587 *      Return
2588 *              **SK_PASS** on success, or **SK_DROP** on error.
2589 *
2590 * long bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
2591 *      Description
2592 *              Add an entry to, or update a *map* referencing sockets. The
2593 *              *skops* is used as a new value for the entry associated to
2594 *              *key*. *flags* is one of:
2595 *
2596 *              **BPF_NOEXIST**
2597 *                      The entry for *key* must not exist in the map.
2598 *              **BPF_EXIST**
2599 *                      The entry for *key* must already exist in the map.
2600 *              **BPF_ANY**
2601 *                      No condition on the existence of the entry for *key*.
2602 *
2603 *              If the *map* has eBPF programs (parser and verdict), those will
2604 *              be inherited by the socket being added. If the socket is
2605 *              already attached to eBPF programs, this results in an error.
2606 *      Return
2607 *              0 on success, or a negative error in case of failure.
2608 *
2609 * long bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
2610 *      Description
2611 *              Adjust the address pointed by *xdp_md*\ **->data_meta** by
2612 *              *delta* (which can be positive or negative). Note that this
2613 *              operation modifies the address stored in *xdp_md*\ **->data**,
2614 *              so the latter must be loaded only after the helper has been
2615 *              called.
2616 *
2617 *              The use of *xdp_md*\ **->data_meta** is optional and programs
2618 *              are not required to use it. The rationale is that when the
2619 *              packet is processed with XDP (e.g. as DoS filter), it is
2620 *              possible to push further meta data along with it before passing
2621 *              to the stack, and to give the guarantee that an ingress eBPF
2622 *              program attached as a TC classifier on the same device can pick
2623 *              this up for further post-processing. Since TC works with socket
2624 *              buffers, it remains possible to set from XDP the **mark** or
2625 *              **priority** pointers, or other pointers for the socket buffer.
2626 *              Having this scratch space generic and programmable allows for
2627 *              more flexibility as the user is free to store whatever meta
2628 *              data they need.
2629 *
2630 *              A call to this helper is susceptible to change the underlying
2631 *              packet buffer. Therefore, at load time, all checks on pointers
2632 *              previously done by the verifier are invalidated and must be
2633 *              performed again, if the helper is used in combination with
2634 *              direct packet access.
2635 *      Return
2636 *              0 on success, or a negative error in case of failure.
2637 *
2638 * long bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
2639 *      Description
2640 *              Read the value of a perf event counter, and store it into *buf*
2641 *              of size *buf_size*. This helper relies on a *map* of type
2642 *              **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
2643 *              counter is selected when *map* is updated with perf event file
2644 *              descriptors. The *map* is an array whose size is the number of
2645 *              available CPUs, and each cell contains a value relative to one
2646 *              CPU. The value to retrieve is indicated by *flags*, that
2647 *              contains the index of the CPU to look up, masked with
2648 *              **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
2649 *              **BPF_F_CURRENT_CPU** to indicate that the value for the
2650 *              current CPU should be retrieved.
2651 *
2652 *              This helper behaves in a way close to
2653 *              **bpf_perf_event_read**\ () helper, save that instead of
2654 *              just returning the value observed, it fills the *buf*
2655 *              structure. This allows for additional data to be retrieved: in
2656 *              particular, the enabled and running times (in *buf*\
2657 *              **->enabled** and *buf*\ **->running**, respectively) are
2658 *              copied. In general, **bpf_perf_event_read_value**\ () is
2659 *              recommended over **bpf_perf_event_read**\ (), which has some
2660 *              ABI issues and provides fewer functionalities.
2661 *
2662 *              These values are interesting, because hardware PMU (Performance
2663 *              Monitoring Unit) counters are limited resources. When there are
2664 *              more PMU based perf events opened than available counters,
2665 *              kernel will multiplex these events so each event gets certain
2666 *              percentage (but not all) of the PMU time. In case that
2667 *              multiplexing happens, the number of samples or counter value
2668 *              will not reflect the case compared to when no multiplexing
2669 *              occurs. This makes comparison between different runs difficult.
2670 *              Typically, the counter value should be normalized before
2671 *              comparing to other experiments. The usual normalization is done
2672 *              as follows.
2673 *
2674 *              ::
2675 *
2676 *                      normalized_counter = counter * t_enabled / t_running
2677 *
2678 *              Where t_enabled is the time enabled for event and t_running is
2679 *              the time running for event since last normalization. The
2680 *              enabled and running times are accumulated since the perf event
2681 *              open. To achieve scaling factor between two invocations of an
2682 *              eBPF program, users can use CPU id as the key (which is
2683 *              typical for perf array usage model) to remember the previous
2684 *              value and do the calculation inside the eBPF program.
2685 *      Return
2686 *              0 on success, or a negative error in case of failure.
2687 *
2688 * long bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
2689 *      Description
2690 *              For en eBPF program attached to a perf event, retrieve the
2691 *              value of the event counter associated to *ctx* and store it in
2692 *              the structure pointed by *buf* and of size *buf_size*. Enabled
2693 *              and running times are also stored in the structure (see
2694 *              description of helper **bpf_perf_event_read_value**\ () for
2695 *              more details).
2696 *      Return
2697 *              0 on success, or a negative error in case of failure.
2698 *
2699 * long bpf_getsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
2700 *      Description
2701 *              Emulate a call to **getsockopt()** on the socket associated to
2702 *              *bpf_socket*, which must be a full socket. The *level* at
2703 *              which the option resides and the name *optname* of the option
2704 *              must be specified, see **getsockopt(2)** for more information.
2705 *              The retrieved value is stored in the structure pointed by
2706 *              *opval* and of length *optlen*.
2707 *
2708 *              *bpf_socket* should be one of the following:
2709 *
2710 *              * **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
2711 *              * **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
2712 *                and **BPF_CGROUP_INET6_CONNECT**.
2713 *
2714 *              This helper actually implements a subset of **getsockopt()**.
2715 *              It supports the following *level*\ s:
2716 *
2717 *              * **IPPROTO_TCP**, which supports *optname*
2718 *                **TCP_CONGESTION**.
2719 *              * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
2720 *              * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
2721 *      Return
2722 *              0 on success, or a negative error in case of failure.
2723 *
2724 * long bpf_override_return(struct pt_regs *regs, u64 rc)
2725 *      Description
2726 *              Used for error injection, this helper uses kprobes to override
2727 *              the return value of the probed function, and to set it to *rc*.
2728 *              The first argument is the context *regs* on which the kprobe
2729 *              works.
2730 *
2731 *              This helper works by setting the PC (program counter)
2732 *              to an override function which is run in place of the original
2733 *              probed function. This means the probed function is not run at
2734 *              all. The replacement function just returns with the required
2735 *              value.
2736 *
2737 *              This helper has security implications, and thus is subject to
2738 *              restrictions. It is only available if the kernel was compiled
2739 *              with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
2740 *              option, and in this case it only works on functions tagged with
2741 *              **ALLOW_ERROR_INJECTION** in the kernel code.
2742 *
2743 *              Also, the helper is only available for the architectures having
2744 *              the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
2745 *              x86 architecture is the only one to support this feature.
2746 *      Return
2747 *              0
2748 *
2749 * long bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
2750 *      Description
2751 *              Attempt to set the value of the **bpf_sock_ops_cb_flags** field
2752 *              for the full TCP socket associated to *bpf_sock_ops* to
2753 *              *argval*.
2754 *
2755 *              The primary use of this field is to determine if there should
2756 *              be calls to eBPF programs of type
2757 *              **BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
2758 *              code. A program of the same type can change its value, per
2759 *              connection and as necessary, when the connection is
2760 *              established. This field is directly accessible for reading, but
2761 *              this helper must be used for updates in order to return an
2762 *              error if an eBPF program tries to set a callback that is not
2763 *              supported in the current kernel.
2764 *
2765 *              *argval* is a flag array which can combine these flags:
2766 *
2767 *              * **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
2768 *              * **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
2769 *              * **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
2770 *              * **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT)
2771 *
2772 *              Therefore, this function can be used to clear a callback flag by
2773 *              setting the appropriate bit to zero. e.g. to disable the RTO
2774 *              callback:
2775 *
2776 *              **bpf_sock_ops_cb_flags_set(bpf_sock,**
2777 *                      **bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)**
2778 *
2779 *              Here are some examples of where one could call such eBPF
2780 *              program:
2781 *
2782 *              * When RTO fires.
2783 *              * When a packet is retransmitted.
2784 *              * When the connection terminates.
2785 *              * When a packet is sent.
2786 *              * When a packet is received.
2787 *      Return
2788 *              Code **-EINVAL** if the socket is not a full TCP socket;
2789 *              otherwise, a positive number containing the bits that could not
2790 *              be set is returned (which comes down to 0 if all bits were set
2791 *              as required).
2792 *
2793 * long bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
2794 *      Description
2795 *              This helper is used in programs implementing policies at the
2796 *              socket level. If the message *msg* is allowed to pass (i.e. if
2797 *              the verdict eBPF program returns **SK_PASS**), redirect it to
2798 *              the socket referenced by *map* (of type
2799 *              **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
2800 *              egress interfaces can be used for redirection. The
2801 *              **BPF_F_INGRESS** value in *flags* is used to make the
2802 *              distinction (ingress path is selected if the flag is present,
2803 *              egress path otherwise). This is the only flag supported for now.
2804 *      Return
2805 *              **SK_PASS** on success, or **SK_DROP** on error.
2806 *
2807 * long bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
2808 *      Description
2809 *              For socket policies, apply the verdict of the eBPF program to
2810 *              the next *bytes* (number of bytes) of message *msg*.
2811 *
2812 *              For example, this helper can be used in the following cases:
2813 *
2814 *              * A single **sendmsg**\ () or **sendfile**\ () system call
2815 *                contains multiple logical messages that the eBPF program is
2816 *                supposed to read and for which it should apply a verdict.
2817 *              * An eBPF program only cares to read the first *bytes* of a
2818 *                *msg*. If the message has a large payload, then setting up
2819 *                and calling the eBPF program repeatedly for all bytes, even
2820 *                though the verdict is already known, would create unnecessary
2821 *                overhead.
2822 *
2823 *              When called from within an eBPF program, the helper sets a
2824 *              counter internal to the BPF infrastructure, that is used to
2825 *              apply the last verdict to the next *bytes*. If *bytes* is
2826 *              smaller than the current data being processed from a
2827 *              **sendmsg**\ () or **sendfile**\ () system call, the first
2828 *              *bytes* will be sent and the eBPF program will be re-run with
2829 *              the pointer for start of data pointing to byte number *bytes*
2830 *              **+ 1**. If *bytes* is larger than the current data being
2831 *              processed, then the eBPF verdict will be applied to multiple
2832 *              **sendmsg**\ () or **sendfile**\ () calls until *bytes* are
2833 *              consumed.
2834 *
2835 *              Note that if a socket closes with the internal counter holding
2836 *              a non-zero value, this is not a problem because data is not
2837 *              being buffered for *bytes* and is sent as it is received.
2838 *      Return
2839 *              0
2840 *
2841 * long bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
2842 *      Description
2843 *              For socket policies, prevent the execution of the verdict eBPF
2844 *              program for message *msg* until *bytes* (byte number) have been
2845 *              accumulated.
2846 *
2847 *              This can be used when one needs a specific number of bytes
2848 *              before a verdict can be assigned, even if the data spans
2849 *              multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
2850 *              case would be a user calling **sendmsg**\ () repeatedly with
2851 *              1-byte long message segments. Obviously, this is bad for
2852 *              performance, but it is still valid. If the eBPF program needs
2853 *              *bytes* bytes to validate a header, this helper can be used to
2854 *              prevent the eBPF program to be called again until *bytes* have
2855 *              been accumulated.
2856 *      Return
2857 *              0
2858 *
2859 * long bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
2860 *      Description
2861 *              For socket policies, pull in non-linear data from user space
2862 *              for *msg* and set pointers *msg*\ **->data** and *msg*\
2863 *              **->data_end** to *start* and *end* bytes offsets into *msg*,
2864 *              respectively.
2865 *
2866 *              If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
2867 *              *msg* it can only parse data that the (**data**, **data_end**)
2868 *              pointers have already consumed. For **sendmsg**\ () hooks this
2869 *              is likely the first scatterlist element. But for calls relying
2870 *              on the **sendpage** handler (e.g. **sendfile**\ ()) this will
2871 *              be the range (**0**, **0**) because the data is shared with
2872 *              user space and by default the objective is to avoid allowing
2873 *              user space to modify data while (or after) eBPF verdict is
2874 *              being decided. This helper can be used to pull in data and to
2875 *              set the start and end pointer to given values. Data will be
2876 *              copied if necessary (i.e. if data was not linear and if start
2877 *              and end pointers do not point to the same chunk).
2878 *
2879 *              A call to this helper is susceptible to change the underlying
2880 *              packet buffer. Therefore, at load time, all checks on pointers
2881 *              previously done by the verifier are invalidated and must be
2882 *              performed again, if the helper is used in combination with
2883 *              direct packet access.
2884 *
2885 *              All values for *flags* are reserved for future usage, and must
2886 *              be left at zero.
2887 *      Return
2888 *              0 on success, or a negative error in case of failure.
2889 *
2890 * long bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
2891 *      Description
2892 *              Bind the socket associated to *ctx* to the address pointed by
2893 *              *addr*, of length *addr_len*. This allows for making outgoing
2894 *              connection from the desired IP address, which can be useful for
2895 *              example when all processes inside a cgroup should use one
2896 *              single IP address on a host that has multiple IP configured.
2897 *
2898 *              This helper works for IPv4 and IPv6, TCP and UDP sockets. The
2899 *              domain (*addr*\ **->sa_family**) must be **AF_INET** (or
2900 *              **AF_INET6**). It's advised to pass zero port (**sin_port**
2901 *              or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like
2902 *              behavior and lets the kernel efficiently pick up an unused
2903 *              port as long as 4-tuple is unique. Passing non-zero port might
2904 *              lead to degraded performance.
2905 *      Return
2906 *              0 on success, or a negative error in case of failure.
2907 *
2908 * long bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
2909 *      Description
2910 *              Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
2911 *              possible to both shrink and grow the packet tail.
2912 *              Shrink done via *delta* being a negative integer.
2913 *
2914 *              A call to this helper is susceptible to change the underlying
2915 *              packet buffer. Therefore, at load time, all checks on pointers
2916 *              previously done by the verifier are invalidated and must be
2917 *              performed again, if the helper is used in combination with
2918 *              direct packet access.
2919 *      Return
2920 *              0 on success, or a negative error in case of failure.
2921 *
2922 * long bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
2923 *      Description
2924 *              Retrieve the XFRM state (IP transform framework, see also
2925 *              **ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
2926 *
2927 *              The retrieved value is stored in the **struct bpf_xfrm_state**
2928 *              pointed by *xfrm_state* and of length *size*.
2929 *
2930 *              All values for *flags* are reserved for future usage, and must
2931 *              be left at zero.
2932 *
2933 *              This helper is available only if the kernel was compiled with
2934 *              **CONFIG_XFRM** configuration option.
2935 *      Return
2936 *              0 on success, or a negative error in case of failure.
2937 *
2938 * long bpf_get_stack(void *ctx, void *buf, u32 size, u64 flags)
2939 *      Description
2940 *              Return a user or a kernel stack in bpf program provided buffer.
2941 *              To achieve this, the helper needs *ctx*, which is a pointer
2942 *              to the context on which the tracing program is executed.
2943 *              To store the stacktrace, the bpf program provides *buf* with
2944 *              a nonnegative *size*.
2945 *
2946 *              The last argument, *flags*, holds the number of stack frames to
2947 *              skip (from 0 to 255), masked with
2948 *              **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
2949 *              the following flags:
2950 *
2951 *              **BPF_F_USER_STACK**
2952 *                      Collect a user space stack instead of a kernel stack.
2953 *              **BPF_F_USER_BUILD_ID**
2954 *                      Collect buildid+offset instead of ips for user stack,
2955 *                      only valid if **BPF_F_USER_STACK** is also specified.
2956 *
2957 *              **bpf_get_stack**\ () can collect up to
2958 *              **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
2959 *              to sufficient large buffer size. Note that
2960 *              this limit can be controlled with the **sysctl** program, and
2961 *              that it should be manually increased in order to profile long
2962 *              user stacks (such as stacks for Java programs). To do so, use:
2963 *
2964 *              ::
2965 *
2966 *                      # sysctl kernel.perf_event_max_stack=<new value>
2967 *      Return
2968 *              A non-negative value equal to or less than *size* on success,
2969 *              or a negative error in case of failure.
2970 *
2971 * long bpf_skb_load_bytes_relative(const void *skb, u32 offset, void *to, u32 len, u32 start_header)
2972 *      Description
2973 *              This helper is similar to **bpf_skb_load_bytes**\ () in that
2974 *              it provides an easy way to load *len* bytes from *offset*
2975 *              from the packet associated to *skb*, into the buffer pointed
2976 *              by *to*. The difference to **bpf_skb_load_bytes**\ () is that
2977 *              a fifth argument *start_header* exists in order to select a
2978 *              base offset to start from. *start_header* can be one of:
2979 *
2980 *              **BPF_HDR_START_MAC**
2981 *                      Base offset to load data from is *skb*'s mac header.
2982 *              **BPF_HDR_START_NET**
2983 *                      Base offset to load data from is *skb*'s network header.
2984 *
2985 *              In general, "direct packet access" is the preferred method to
2986 *              access packet data, however, this helper is in particular useful
2987 *              in socket filters where *skb*\ **->data** does not always point
2988 *              to the start of the mac header and where "direct packet access"
2989 *              is not available.
2990 *      Return
2991 *              0 on success, or a negative error in case of failure.
2992 *
2993 * long bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
2994 *      Description
2995 *              Do FIB lookup in kernel tables using parameters in *params*.
2996 *              If lookup is successful and result shows packet is to be
2997 *              forwarded, the neighbor tables are searched for the nexthop.
2998 *              If successful (ie., FIB lookup shows forwarding and nexthop
2999 *              is resolved), the nexthop address is returned in ipv4_dst
3000 *              or ipv6_dst based on family, smac is set to mac address of
3001 *              egress device, dmac is set to nexthop mac address, rt_metric
3002 *              is set to metric from route (IPv4/IPv6 only), and ifindex
3003 *              is set to the device index of the nexthop from the FIB lookup.
3004 *
3005 *              *plen* argument is the size of the passed in struct.
3006 *              *flags* argument can be a combination of one or more of the
3007 *              following values:
3008 *
3009 *              **BPF_FIB_LOOKUP_DIRECT**
3010 *                      Do a direct table lookup vs full lookup using FIB
3011 *                      rules.
3012 *              **BPF_FIB_LOOKUP_OUTPUT**
3013 *                      Perform lookup from an egress perspective (default is
3014 *                      ingress).
3015 *
3016 *              *ctx* is either **struct xdp_md** for XDP programs or
3017 *              **struct sk_buff** tc cls_act programs.
3018 *      Return
3019 *              * < 0 if any input argument is invalid
3020 *              *   0 on success (packet is forwarded, nexthop neighbor exists)
3021 *              * > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
3022 *                packet is not forwarded or needs assist from full stack
3023 *
3024 *              If lookup fails with BPF_FIB_LKUP_RET_FRAG_NEEDED, then the MTU
3025 *              was exceeded and output params->mtu_result contains the MTU.
3026 *
3027 * long bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
3028 *      Description
3029 *              Add an entry to, or update a sockhash *map* referencing sockets.
3030 *              The *skops* is used as a new value for the entry associated to
3031 *              *key*. *flags* is one of:
3032 *
3033 *              **BPF_NOEXIST**
3034 *                      The entry for *key* must not exist in the map.
3035 *              **BPF_EXIST**
3036 *                      The entry for *key* must already exist in the map.
3037 *              **BPF_ANY**
3038 *                      No condition on the existence of the entry for *key*.
3039 *
3040 *              If the *map* has eBPF programs (parser and verdict), those will
3041 *              be inherited by the socket being added. If the socket is
3042 *              already attached to eBPF programs, this results in an error.
3043 *      Return
3044 *              0 on success, or a negative error in case of failure.
3045 *
3046 * long bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
3047 *      Description
3048 *              This helper is used in programs implementing policies at the
3049 *              socket level. If the message *msg* is allowed to pass (i.e. if
3050 *              the verdict eBPF program returns **SK_PASS**), redirect it to
3051 *              the socket referenced by *map* (of type
3052 *              **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
3053 *              egress interfaces can be used for redirection. The
3054 *              **BPF_F_INGRESS** value in *flags* is used to make the
3055 *              distinction (ingress path is selected if the flag is present,
3056 *              egress path otherwise). This is the only flag supported for now.
3057 *      Return
3058 *              **SK_PASS** on success, or **SK_DROP** on error.
3059 *
3060 * long bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
3061 *      Description
3062 *              This helper is used in programs implementing policies at the
3063 *              skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
3064 *              if the verdict eBPF program returns **SK_PASS**), redirect it
3065 *              to the socket referenced by *map* (of type
3066 *              **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
3067 *              egress interfaces can be used for redirection. The
3068 *              **BPF_F_INGRESS** value in *flags* is used to make the
3069 *              distinction (ingress path is selected if the flag is present,
3070 *              egress otherwise). This is the only flag supported for now.
3071 *      Return
3072 *              **SK_PASS** on success, or **SK_DROP** on error.
3073 *
3074 * long bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
3075 *      Description
3076 *              Encapsulate the packet associated to *skb* within a Layer 3
3077 *              protocol header. This header is provided in the buffer at
3078 *              address *hdr*, with *len* its size in bytes. *type* indicates
3079 *              the protocol of the header and can be one of:
3080 *
3081 *              **BPF_LWT_ENCAP_SEG6**
3082 *                      IPv6 encapsulation with Segment Routing Header
3083 *                      (**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
3084 *                      the IPv6 header is computed by the kernel.
3085 *              **BPF_LWT_ENCAP_SEG6_INLINE**
3086 *                      Only works if *skb* contains an IPv6 packet. Insert a
3087 *                      Segment Routing Header (**struct ipv6_sr_hdr**) inside
3088 *                      the IPv6 header.
3089 *              **BPF_LWT_ENCAP_IP**
3090 *                      IP encapsulation (GRE/GUE/IPIP/etc). The outer header
3091 *                      must be IPv4 or IPv6, followed by zero or more
3092 *                      additional headers, up to **LWT_BPF_MAX_HEADROOM**
3093 *                      total bytes in all prepended headers. Please note that
3094 *                      if **skb_is_gso**\ (*skb*) is true, no more than two
3095 *                      headers can be prepended, and the inner header, if
3096 *                      present, should be either GRE or UDP/GUE.
3097 *
3098 *              **BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs
3099 *              of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can
3100 *              be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and
3101 *              **BPF_PROG_TYPE_LWT_XMIT**.
3102 *
3103 *              A call to this helper is susceptible to change the underlying
3104 *              packet buffer. Therefore, at load time, all checks on pointers
3105 *              previously done by the verifier are invalidated and must be
3106 *              performed again, if the helper is used in combination with
3107 *              direct packet access.
3108 *      Return
3109 *              0 on success, or a negative error in case of failure.
3110 *
3111 * long bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
3112 *      Description
3113 *              Store *len* bytes from address *from* into the packet
3114 *              associated to *skb*, at *offset*. Only the flags, tag and TLVs
3115 *              inside the outermost IPv6 Segment Routing Header can be
3116 *              modified through this helper.
3117 *
3118 *              A call to this helper is susceptible to change the underlying
3119 *              packet buffer. Therefore, at load time, all checks on pointers
3120 *              previously done by the verifier are invalidated and must be
3121 *              performed again, if the helper is used in combination with
3122 *              direct packet access.
3123 *      Return
3124 *              0 on success, or a negative error in case of failure.
3125 *
3126 * long bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
3127 *      Description
3128 *              Adjust the size allocated to TLVs in the outermost IPv6
3129 *              Segment Routing Header contained in the packet associated to
3130 *              *skb*, at position *offset* by *delta* bytes. Only offsets
3131 *              after the segments are accepted. *delta* can be as well
3132 *              positive (growing) as negative (shrinking).
3133 *
3134 *              A call to this helper is susceptible to change the underlying
3135 *              packet buffer. Therefore, at load time, all checks on pointers
3136 *              previously done by the verifier are invalidated and must be
3137 *              performed again, if the helper is used in combination with
3138 *              direct packet access.
3139 *      Return
3140 *              0 on success, or a negative error in case of failure.
3141 *
3142 * long bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
3143 *      Description
3144 *              Apply an IPv6 Segment Routing action of type *action* to the
3145 *              packet associated to *skb*. Each action takes a parameter
3146 *              contained at address *param*, and of length *param_len* bytes.
3147 *              *action* can be one of:
3148 *
3149 *              **SEG6_LOCAL_ACTION_END_X**
3150 *                      End.X action: Endpoint with Layer-3 cross-connect.
3151 *                      Type of *param*: **struct in6_addr**.
3152 *              **SEG6_LOCAL_ACTION_END_T**
3153 *                      End.T action: Endpoint with specific IPv6 table lookup.
3154 *                      Type of *param*: **int**.
3155 *              **SEG6_LOCAL_ACTION_END_B6**
3156 *                      End.B6 action: Endpoint bound to an SRv6 policy.
3157 *                      Type of *param*: **struct ipv6_sr_hdr**.
3158 *              **SEG6_LOCAL_ACTION_END_B6_ENCAP**
3159 *                      End.B6.Encap action: Endpoint bound to an SRv6
3160 *                      encapsulation policy.
3161 *                      Type of *param*: **struct ipv6_sr_hdr**.
3162 *
3163 *              A call to this helper is susceptible to change the underlying
3164 *              packet buffer. Therefore, at load time, all checks on pointers
3165 *              previously done by the verifier are invalidated and must be
3166 *              performed again, if the helper is used in combination with
3167 *              direct packet access.
3168 *      Return
3169 *              0 on success, or a negative error in case of failure.
3170 *
3171 * long bpf_rc_repeat(void *ctx)
3172 *      Description
3173 *              This helper is used in programs implementing IR decoding, to
3174 *              report a successfully decoded repeat key message. This delays
3175 *              the generation of a key up event for previously generated
3176 *              key down event.
3177 *
3178 *              Some IR protocols like NEC have a special IR message for
3179 *              repeating last button, for when a button is held down.
3180 *
3181 *              The *ctx* should point to the lirc sample as passed into
3182 *              the program.
3183 *
3184 *              This helper is only available is the kernel was compiled with
3185 *              the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3186 *              "**y**".
3187 *      Return
3188 *              0
3189 *
3190 * long bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
3191 *      Description
3192 *              This helper is used in programs implementing IR decoding, to
3193 *              report a successfully decoded key press with *scancode*,
3194 *              *toggle* value in the given *protocol*. The scancode will be
3195 *              translated to a keycode using the rc keymap, and reported as
3196 *              an input key down event. After a period a key up event is
3197 *              generated. This period can be extended by calling either
3198 *              **bpf_rc_keydown**\ () again with the same values, or calling
3199 *              **bpf_rc_repeat**\ ().
3200 *
3201 *              Some protocols include a toggle bit, in case the button was
3202 *              released and pressed again between consecutive scancodes.
3203 *
3204 *              The *ctx* should point to the lirc sample as passed into
3205 *              the program.
3206 *
3207 *              The *protocol* is the decoded protocol number (see
3208 *              **enum rc_proto** for some predefined values).
3209 *
3210 *              This helper is only available is the kernel was compiled with
3211 *              the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3212 *              "**y**".
3213 *      Return
3214 *              0
3215 *
3216 * u64 bpf_skb_cgroup_id(struct sk_buff *skb)
3217 *      Description
3218 *              Return the cgroup v2 id of the socket associated with the *skb*.
3219 *              This is roughly similar to the **bpf_get_cgroup_classid**\ ()
3220 *              helper for cgroup v1 by providing a tag resp. identifier that
3221 *              can be matched on or used for map lookups e.g. to implement
3222 *              policy. The cgroup v2 id of a given path in the hierarchy is
3223 *              exposed in user space through the f_handle API in order to get
3224 *              to the same 64-bit id.
3225 *
3226 *              This helper can be used on TC egress path, but not on ingress,
3227 *              and is available only if the kernel was compiled with the
3228 *              **CONFIG_SOCK_CGROUP_DATA** configuration option.
3229 *      Return
3230 *              The id is returned or 0 in case the id could not be retrieved.
3231 *
3232 * u64 bpf_get_current_cgroup_id(void)
3233 *      Return
3234 *              A 64-bit integer containing the current cgroup id based
3235 *              on the cgroup within which the current task is running.
3236 *
3237 * void *bpf_get_local_storage(void *map, u64 flags)
3238 *      Description
3239 *              Get the pointer to the local storage area.
3240 *              The type and the size of the local storage is defined
3241 *              by the *map* argument.
3242 *              The *flags* meaning is specific for each map type,
3243 *              and has to be 0 for cgroup local storage.
3244 *
3245 *              Depending on the BPF program type, a local storage area
3246 *              can be shared between multiple instances of the BPF program,
3247 *              running simultaneously.
3248 *
3249 *              A user should care about the synchronization by himself.
3250 *              For example, by using the **BPF_ATOMIC** instructions to alter
3251 *              the shared data.
3252 *      Return
3253 *              A pointer to the local storage area.
3254 *
3255 * long bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
3256 *      Description
3257 *              Select a **SO_REUSEPORT** socket from a
3258 *              **BPF_MAP_TYPE_REUSEPORT_SOCKARRAY** *map*.
3259 *              It checks the selected socket is matching the incoming
3260 *              request in the socket buffer.
3261 *      Return
3262 *              0 on success, or a negative error in case of failure.
3263 *
3264 * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
3265 *      Description
3266 *              Return id of cgroup v2 that is ancestor of cgroup associated
3267 *              with the *skb* at the *ancestor_level*.  The root cgroup is at
3268 *              *ancestor_level* zero and each step down the hierarchy
3269 *              increments the level. If *ancestor_level* == level of cgroup
3270 *              associated with *skb*, then return value will be same as that
3271 *              of **bpf_skb_cgroup_id**\ ().
3272 *
3273 *              The helper is useful to implement policies based on cgroups
3274 *              that are upper in hierarchy than immediate cgroup associated
3275 *              with *skb*.
3276 *
3277 *              The format of returned id and helper limitations are same as in
3278 *              **bpf_skb_cgroup_id**\ ().
3279 *      Return
3280 *              The id is returned or 0 in case the id could not be retrieved.
3281 *
3282 * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3283 *      Description
3284 *              Look for TCP socket matching *tuple*, optionally in a child
3285 *              network namespace *netns*. The return value must be checked,
3286 *              and if non-**NULL**, released via **bpf_sk_release**\ ().
3287 *
3288 *              The *ctx* should point to the context of the program, such as
3289 *              the skb or socket (depending on the hook in use). This is used
3290 *              to determine the base network namespace for the lookup.
3291 *
3292 *              *tuple_size* must be one of:
3293 *
3294 *              **sizeof**\ (*tuple*\ **->ipv4**)
3295 *                      Look for an IPv4 socket.
3296 *              **sizeof**\ (*tuple*\ **->ipv6**)
3297 *                      Look for an IPv6 socket.
3298 *
3299 *              If the *netns* is a negative signed 32-bit integer, then the
3300 *              socket lookup table in the netns associated with the *ctx*
3301 *              will be used. For the TC hooks, this is the netns of the device
3302 *              in the skb. For socket hooks, this is the netns of the socket.
3303 *              If *netns* is any other signed 32-bit value greater than or
3304 *              equal to zero then it specifies the ID of the netns relative to
3305 *              the netns associated with the *ctx*. *netns* values beyond the
3306 *              range of 32-bit integers are reserved for future use.
3307 *
3308 *              All values for *flags* are reserved for future usage, and must
3309 *              be left at zero.
3310 *
3311 *              This helper is available only if the kernel was compiled with
3312 *              **CONFIG_NET** configuration option.
3313 *      Return
3314 *              Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3315 *              For sockets with reuseport option, the **struct bpf_sock**
3316 *              result is from *reuse*\ **->socks**\ [] using the hash of the
3317 *              tuple.
3318 *
3319 * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3320 *      Description
3321 *              Look for UDP socket matching *tuple*, optionally in a child
3322 *              network namespace *netns*. The return value must be checked,
3323 *              and if non-**NULL**, released via **bpf_sk_release**\ ().
3324 *
3325 *              The *ctx* should point to the context of the program, such as
3326 *              the skb or socket (depending on the hook in use). This is used
3327 *              to determine the base network namespace for the lookup.
3328 *
3329 *              *tuple_size* must be one of:
3330 *
3331 *              **sizeof**\ (*tuple*\ **->ipv4**)
3332 *                      Look for an IPv4 socket.
3333 *              **sizeof**\ (*tuple*\ **->ipv6**)
3334 *                      Look for an IPv6 socket.
3335 *
3336 *              If the *netns* is a negative signed 32-bit integer, then the
3337 *              socket lookup table in the netns associated with the *ctx*
3338 *              will be used. For the TC hooks, this is the netns of the device
3339 *              in the skb. For socket hooks, this is the netns of the socket.
3340 *              If *netns* is any other signed 32-bit value greater than or
3341 *              equal to zero then it specifies the ID of the netns relative to
3342 *              the netns associated with the *ctx*. *netns* values beyond the
3343 *              range of 32-bit integers are reserved for future use.
3344 *
3345 *              All values for *flags* are reserved for future usage, and must
3346 *              be left at zero.
3347 *
3348 *              This helper is available only if the kernel was compiled with
3349 *              **CONFIG_NET** configuration option.
3350 *      Return
3351 *              Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3352 *              For sockets with reuseport option, the **struct bpf_sock**
3353 *              result is from *reuse*\ **->socks**\ [] using the hash of the
3354 *              tuple.
3355 *
3356 * long bpf_sk_release(void *sock)
3357 *      Description
3358 *              Release the reference held by *sock*. *sock* must be a
3359 *              non-**NULL** pointer that was returned from
3360 *              **bpf_sk_lookup_xxx**\ ().
3361 *      Return
3362 *              0 on success, or a negative error in case of failure.
3363 *
3364 * long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
3365 *      Description
3366 *              Push an element *value* in *map*. *flags* is one of:
3367 *
3368 *              **BPF_EXIST**
3369 *                      If the queue/stack is full, the oldest element is
3370 *                      removed to make room for this.
3371 *      Return
3372 *              0 on success, or a negative error in case of failure.
3373 *
3374 * long bpf_map_pop_elem(struct bpf_map *map, void *value)
3375 *      Description
3376 *              Pop an element from *map*.
3377 *      Return
3378 *              0 on success, or a negative error in case of failure.
3379 *
3380 * long bpf_map_peek_elem(struct bpf_map *map, void *value)
3381 *      Description
3382 *              Get an element from *map* without removing it.
3383 *      Return
3384 *              0 on success, or a negative error in case of failure.
3385 *
3386 * long bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3387 *      Description
3388 *              For socket policies, insert *len* bytes into *msg* at offset
3389 *              *start*.
3390 *
3391 *              If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
3392 *              *msg* it may want to insert metadata or options into the *msg*.
3393 *              This can later be read and used by any of the lower layer BPF
3394 *              hooks.
3395 *
3396 *              This helper may fail if under memory pressure (a malloc
3397 *              fails) in these cases BPF programs will get an appropriate
3398 *              error and BPF programs will need to handle them.
3399 *      Return
3400 *              0 on success, or a negative error in case of failure.
3401 *
3402 * long bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3403 *      Description
3404 *              Will remove *len* bytes from a *msg* starting at byte *start*.
3405 *              This may result in **ENOMEM** errors under certain situations if
3406 *              an allocation and copy are required due to a full ring buffer.
3407 *              However, the helper will try to avoid doing the allocation
3408 *              if possible. Other errors can occur if input parameters are
3409 *              invalid either due to *start* byte not being valid part of *msg*
3410 *              payload and/or *pop* value being to large.
3411 *      Return
3412 *              0 on success, or a negative error in case of failure.
3413 *
3414 * long bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
3415 *      Description
3416 *              This helper is used in programs implementing IR decoding, to
3417 *              report a successfully decoded pointer movement.
3418 *
3419 *              The *ctx* should point to the lirc sample as passed into
3420 *              the program.
3421 *
3422 *              This helper is only available is the kernel was compiled with
3423 *              the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3424 *              "**y**".
3425 *      Return
3426 *              0
3427 *
3428 * long bpf_spin_lock(struct bpf_spin_lock *lock)
3429 *      Description
3430 *              Acquire a spinlock represented by the pointer *lock*, which is
3431 *              stored as part of a value of a map. Taking the lock allows to
3432 *              safely update the rest of the fields in that value. The
3433 *              spinlock can (and must) later be released with a call to
3434 *              **bpf_spin_unlock**\ (\ *lock*\ ).
3435 *
3436 *              Spinlocks in BPF programs come with a number of restrictions
3437 *              and constraints:
3438 *
3439 *              * **bpf_spin_lock** objects are only allowed inside maps of
3440 *                types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
3441 *                list could be extended in the future).
3442 *              * BTF description of the map is mandatory.
3443 *              * The BPF program can take ONE lock at a time, since taking two
3444 *                or more could cause dead locks.
3445 *              * Only one **struct bpf_spin_lock** is allowed per map element.
3446 *              * When the lock is taken, calls (either BPF to BPF or helpers)
3447 *                are not allowed.
3448 *              * The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
3449 *                allowed inside a spinlock-ed region.
3450 *              * The BPF program MUST call **bpf_spin_unlock**\ () to release
3451 *                the lock, on all execution paths, before it returns.
3452 *              * The BPF program can access **struct bpf_spin_lock** only via
3453 *                the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
3454 *                helpers. Loading or storing data into the **struct
3455 *                bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
3456 *              * To use the **bpf_spin_lock**\ () helper, the BTF description
3457 *                of the map value must be a struct and have **struct
3458 *                bpf_spin_lock** *anyname*\ **;** field at the top level.
3459 *                Nested lock inside another struct is not allowed.
3460 *              * The **struct bpf_spin_lock** *lock* field in a map value must
3461 *                be aligned on a multiple of 4 bytes in that value.
3462 *              * Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
3463 *                the **bpf_spin_lock** field to user space.
3464 *              * Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
3465 *                a BPF program, do not update the **bpf_spin_lock** field.
3466 *              * **bpf_spin_lock** cannot be on the stack or inside a
3467 *                networking packet (it can only be inside of a map values).
3468 *              * **bpf_spin_lock** is available to root only.
3469 *              * Tracing programs and socket filter programs cannot use
3470 *                **bpf_spin_lock**\ () due to insufficient preemption checks
3471 *                (but this may change in the future).
3472 *              * **bpf_spin_lock** is not allowed in inner maps of map-in-map.
3473 *      Return
3474 *              0
3475 *
3476 * long bpf_spin_unlock(struct bpf_spin_lock *lock)
3477 *      Description
3478 *              Release the *lock* previously locked by a call to
3479 *              **bpf_spin_lock**\ (\ *lock*\ ).
3480 *      Return
3481 *              0
3482 *
3483 * struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
3484 *      Description
3485 *              This helper gets a **struct bpf_sock** pointer such
3486 *              that all the fields in this **bpf_sock** can be accessed.
3487 *      Return
3488 *              A **struct bpf_sock** pointer on success, or **NULL** in
3489 *              case of failure.
3490 *
3491 * struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
3492 *      Description
3493 *              This helper gets a **struct bpf_tcp_sock** pointer from a
3494 *              **struct bpf_sock** pointer.
3495 *      Return
3496 *              A **struct bpf_tcp_sock** pointer on success, or **NULL** in
3497 *              case of failure.
3498 *
3499 * long bpf_skb_ecn_set_ce(struct sk_buff *skb)
3500 *      Description
3501 *              Set ECN (Explicit Congestion Notification) field of IP header
3502 *              to **CE** (Congestion Encountered) if current value is **ECT**
3503 *              (ECN Capable Transport). Otherwise, do nothing. Works with IPv6
3504 *              and IPv4.
3505 *      Return
3506 *              1 if the **CE** flag is set (either by the current helper call
3507 *              or because it was already present), 0 if it is not set.
3508 *
3509 * struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)
3510 *      Description
3511 *              Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
3512 *              **bpf_sk_release**\ () is unnecessary and not allowed.
3513 *      Return
3514 *              A **struct bpf_sock** pointer on success, or **NULL** in
3515 *              case of failure.
3516 *
3517 * struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3518 *      Description
3519 *              Look for TCP socket matching *tuple*, optionally in a child
3520 *              network namespace *netns*. The return value must be checked,
3521 *              and if non-**NULL**, released via **bpf_sk_release**\ ().
3522 *
3523 *              This function is identical to **bpf_sk_lookup_tcp**\ (), except
3524 *              that it also returns timewait or request sockets. Use
3525 *              **bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the
3526 *              full structure.
3527 *
3528 *              This helper is available only if the kernel was compiled with
3529 *              **CONFIG_NET** configuration option.
3530 *      Return
3531 *              Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3532 *              For sockets with reuseport option, the **struct bpf_sock**
3533 *              result is from *reuse*\ **->socks**\ [] using the hash of the
3534 *              tuple.
3535 *
3536 * long bpf_tcp_check_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3537 *      Description
3538 *              Check whether *iph* and *th* contain a valid SYN cookie ACK for
3539 *              the listening socket in *sk*.
3540 *
3541 *              *iph* points to the start of the IPv4 or IPv6 header, while
3542 *              *iph_len* contains **sizeof**\ (**struct iphdr**) or
3543 *              **sizeof**\ (**struct ip6hdr**).
3544 *
3545 *              *th* points to the start of the TCP header, while *th_len*
3546 *              contains **sizeof**\ (**struct tcphdr**).
3547 *      Return
3548 *              0 if *iph* and *th* are a valid SYN cookie ACK, or a negative
3549 *              error otherwise.
3550 *
3551 * long bpf_sysctl_get_name(struct bpf_sysctl *ctx, char *buf, size_t buf_len, u64 flags)
3552 *      Description
3553 *              Get name of sysctl in /proc/sys/ and copy it into provided by
3554 *              program buffer *buf* of size *buf_len*.
3555 *
3556 *              The buffer is always NUL terminated, unless it's zero-sized.
3557 *
3558 *              If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is
3559 *              copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name
3560 *              only (e.g. "tcp_mem").
3561 *      Return
3562 *              Number of character copied (not including the trailing NUL).
3563 *
3564 *              **-E2BIG** if the buffer wasn't big enough (*buf* will contain
3565 *              truncated name in this case).
3566 *
3567 * long bpf_sysctl_get_current_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
3568 *      Description
3569 *              Get current value of sysctl as it is presented in /proc/sys
3570 *              (incl. newline, etc), and copy it as a string into provided
3571 *              by program buffer *buf* of size *buf_len*.
3572 *
3573 *              The whole value is copied, no matter what file position user
3574 *              space issued e.g. sys_read at.
3575 *
3576 *              The buffer is always NUL terminated, unless it's zero-sized.
3577 *      Return
3578 *              Number of character copied (not including the trailing NUL).
3579 *
3580 *              **-E2BIG** if the buffer wasn't big enough (*buf* will contain
3581 *              truncated name in this case).
3582 *
3583 *              **-EINVAL** if current value was unavailable, e.g. because
3584 *              sysctl is uninitialized and read returns -EIO for it.
3585 *
3586 * long bpf_sysctl_get_new_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
3587 *      Description
3588 *              Get new value being written by user space to sysctl (before
3589 *              the actual write happens) and copy it as a string into
3590 *              provided by program buffer *buf* of size *buf_len*.
3591 *
3592 *              User space may write new value at file position > 0.
3593 *
3594 *              The buffer is always NUL terminated, unless it's zero-sized.
3595 *      Return
3596 *              Number of character copied (not including the trailing NUL).
3597 *
3598 *              **-E2BIG** if the buffer wasn't big enough (*buf* will contain
3599 *              truncated name in this case).
3600 *
3601 *              **-EINVAL** if sysctl is being read.
3602 *
3603 * long bpf_sysctl_set_new_value(struct bpf_sysctl *ctx, const char *buf, size_t buf_len)
3604 *      Description
3605 *              Override new value being written by user space to sysctl with
3606 *              value provided by program in buffer *buf* of size *buf_len*.
3607 *
3608 *              *buf* should contain a string in same form as provided by user
3609 *              space on sysctl write.
3610 *
3611 *              User space may write new value at file position > 0. To override
3612 *              the whole sysctl value file position should be set to zero.
3613 *      Return
3614 *              0 on success.
3615 *
3616 *              **-E2BIG** if the *buf_len* is too big.
3617 *
3618 *              **-EINVAL** if sysctl is being read.
3619 *
3620 * long bpf_strtol(const char *buf, size_t buf_len, u64 flags, long *res)
3621 *      Description
3622 *              Convert the initial part of the string from buffer *buf* of
3623 *              size *buf_len* to a long integer according to the given base
3624 *              and save the result in *res*.
3625 *
3626 *              The string may begin with an arbitrary amount of white space
3627 *              (as determined by **isspace**\ (3)) followed by a single
3628 *              optional '**-**' sign.
3629 *
3630 *              Five least significant bits of *flags* encode base, other bits
3631 *              are currently unused.
3632 *
3633 *              Base must be either 8, 10, 16 or 0 to detect it automatically
3634 *              similar to user space **strtol**\ (3).
3635 *      Return
3636 *              Number of characters consumed on success. Must be positive but
3637 *              no more than *buf_len*.
3638 *
3639 *              **-EINVAL** if no valid digits were found or unsupported base
3640 *              was provided.
3641 *
3642 *              **-ERANGE** if resulting value was out of range.
3643 *
3644 * long bpf_strtoul(const char *buf, size_t buf_len, u64 flags, unsigned long *res)
3645 *      Description
3646 *              Convert the initial part of the string from buffer *buf* of
3647 *              size *buf_len* to an unsigned long integer according to the
3648 *              given base and save the result in *res*.
3649 *
3650 *              The string may begin with an arbitrary amount of white space
3651 *              (as determined by **isspace**\ (3)).
3652 *
3653 *              Five least significant bits of *flags* encode base, other bits
3654 *              are currently unused.
3655 *
3656 *              Base must be either 8, 10, 16 or 0 to detect it automatically
3657 *              similar to user space **strtoul**\ (3).
3658 *      Return
3659 *              Number of characters consumed on success. Must be positive but
3660 *              no more than *buf_len*.
3661 *
3662 *              **-EINVAL** if no valid digits were found or unsupported base
3663 *              was provided.
3664 *
3665 *              **-ERANGE** if resulting value was out of range.
3666 *
3667 * void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags)
3668 *      Description
3669 *              Get a bpf-local-storage from a *sk*.
3670 *
3671 *              Logically, it could be thought of getting the value from
3672 *              a *map* with *sk* as the **key**.  From this
3673 *              perspective,  the usage is not much different from
3674 *              **bpf_map_lookup_elem**\ (*map*, **&**\ *sk*) except this
3675 *              helper enforces the key must be a full socket and the map must
3676 *              be a **BPF_MAP_TYPE_SK_STORAGE** also.
3677 *
3678 *              Underneath, the value is stored locally at *sk* instead of
3679 *              the *map*.  The *map* is used as the bpf-local-storage
3680 *              "type". The bpf-local-storage "type" (i.e. the *map*) is
3681 *              searched against all bpf-local-storages residing at *sk*.
3682 *
3683 *              *sk* is a kernel **struct sock** pointer for LSM program.
3684 *              *sk* is a **struct bpf_sock** pointer for other program types.
3685 *
3686 *              An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
3687 *              used such that a new bpf-local-storage will be
3688 *              created if one does not exist.  *value* can be used
3689 *              together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
3690 *              the initial value of a bpf-local-storage.  If *value* is
3691 *              **NULL**, the new bpf-local-storage will be zero initialized.
3692 *      Return
3693 *              A bpf-local-storage pointer is returned on success.
3694 *
3695 *              **NULL** if not found or there was an error in adding
3696 *              a new bpf-local-storage.
3697 *
3698 * long bpf_sk_storage_delete(struct bpf_map *map, void *sk)
3699 *      Description
3700 *              Delete a bpf-local-storage from a *sk*.
3701 *      Return
3702 *              0 on success.
3703 *
3704 *              **-ENOENT** if the bpf-local-storage cannot be found.
3705 *              **-EINVAL** if sk is not a fullsock (e.g. a request_sock).
3706 *
3707 * long bpf_send_signal(u32 sig)
3708 *      Description
3709 *              Send signal *sig* to the process of the current task.
3710 *              The signal may be delivered to any of this process's threads.
3711 *      Return
3712 *              0 on success or successfully queued.
3713 *
3714 *              **-EBUSY** if work queue under nmi is full.
3715 *
3716 *              **-EINVAL** if *sig* is invalid.
3717 *
3718 *              **-EPERM** if no permission to send the *sig*.
3719 *
3720 *              **-EAGAIN** if bpf program can try again.
3721 *
3722 * s64 bpf_tcp_gen_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3723 *      Description
3724 *              Try to issue a SYN cookie for the packet with corresponding
3725 *              IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
3726 *
3727 *              *iph* points to the start of the IPv4 or IPv6 header, while
3728 *              *iph_len* contains **sizeof**\ (**struct iphdr**) or
3729 *              **sizeof**\ (**struct ip6hdr**).
3730 *
3731 *              *th* points to the start of the TCP header, while *th_len*
3732 *              contains the length of the TCP header.
3733 *      Return
3734 *              On success, lower 32 bits hold the generated SYN cookie in
3735 *              followed by 16 bits which hold the MSS value for that cookie,
3736 *              and the top 16 bits are unused.
3737 *
3738 *              On failure, the returned value is one of the following:
3739 *
3740 *              **-EINVAL** SYN cookie cannot be issued due to error
3741 *
3742 *              **-ENOENT** SYN cookie should not be issued (no SYN flood)
3743 *
3744 *              **-EOPNOTSUPP** kernel configuration does not enable SYN cookies
3745 *
3746 *              **-EPROTONOSUPPORT** IP packet version is not 4 or 6
3747 *
3748 * long bpf_skb_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
3749 *      Description
3750 *              Write raw *data* blob into a special BPF perf event held by
3751 *              *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
3752 *              event must have the following attributes: **PERF_SAMPLE_RAW**
3753 *              as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
3754 *              **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
3755 *
3756 *              The *flags* are used to indicate the index in *map* for which
3757 *              the value must be put, masked with **BPF_F_INDEX_MASK**.
3758 *              Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
3759 *              to indicate that the index of the current CPU core should be
3760 *              used.
3761 *
3762 *              The value to write, of *size*, is passed through eBPF stack and
3763 *              pointed by *data*.
3764 *
3765 *              *ctx* is a pointer to in-kernel struct sk_buff.
3766 *
3767 *              This helper is similar to **bpf_perf_event_output**\ () but
3768 *              restricted to raw_tracepoint bpf programs.
3769 *      Return
3770 *              0 on success, or a negative error in case of failure.
3771 *
3772 * long bpf_probe_read_user(void *dst, u32 size, const void *unsafe_ptr)
3773 *      Description
3774 *              Safely attempt to read *size* bytes from user space address
3775 *              *unsafe_ptr* and store the data in *dst*.
3776 *      Return
3777 *              0 on success, or a negative error in case of failure.
3778 *
3779 * long bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
3780 *      Description
3781 *              Safely attempt to read *size* bytes from kernel space address
3782 *              *unsafe_ptr* and store the data in *dst*.
3783 *      Return
3784 *              0 on success, or a negative error in case of failure.
3785 *
3786 * long bpf_probe_read_user_str(void *dst, u32 size, const void *unsafe_ptr)
3787 *      Description
3788 *              Copy a NUL terminated string from an unsafe user address
3789 *              *unsafe_ptr* to *dst*. The *size* should include the
3790 *              terminating NUL byte. In case the string length is smaller than
3791 *              *size*, the target is not padded with further NUL bytes. If the
3792 *              string length is larger than *size*, just *size*-1 bytes are
3793 *              copied and the last byte is set to NUL.
3794 *
3795 *              On success, returns the number of bytes that were written,
3796 *              including the terminal NUL. This makes this helper useful in
3797 *              tracing programs for reading strings, and more importantly to
3798 *              get its length at runtime. See the following snippet:
3799 *
3800 *              ::
3801 *
3802 *                      SEC("kprobe/sys_open")
3803 *                      void bpf_sys_open(struct pt_regs *ctx)
3804 *                      {
3805 *                              char buf[PATHLEN]; // PATHLEN is defined to 256
3806 *                              int res = bpf_probe_read_user_str(buf, sizeof(buf),
3807 *                                                                ctx->di);
3808 *
3809 *                              // Consume buf, for example push it to
3810 *                              // userspace via bpf_perf_event_output(); we
3811 *                              // can use res (the string length) as event
3812 *                              // size, after checking its boundaries.
3813 *                      }
3814 *
3815 *              In comparison, using **bpf_probe_read_user**\ () helper here
3816 *              instead to read the string would require to estimate the length
3817 *              at compile time, and would often result in copying more memory
3818 *              than necessary.
3819 *
3820 *              Another useful use case is when parsing individual process
3821 *              arguments or individual environment variables navigating
3822 *              *current*\ **->mm->arg_start** and *current*\
3823 *              **->mm->env_start**: using this helper and the return value,
3824 *              one can quickly iterate at the right offset of the memory area.
3825 *      Return
3826 *              On success, the strictly positive length of the output string,
3827 *              including the trailing NUL character. On error, a negative
3828 *              value.
3829 *
3830 * long bpf_probe_read_kernel_str(void *dst, u32 size, const void *unsafe_ptr)
3831 *      Description
3832 *              Copy a NUL terminated string from an unsafe kernel address *unsafe_ptr*
3833 *              to *dst*. Same semantics as with **bpf_probe_read_user_str**\ () apply.
3834 *      Return
3835 *              On success, the strictly positive length of the string, including
3836 *              the trailing NUL character. On error, a negative value.
3837 *
3838 * long bpf_tcp_send_ack(void *tp, u32 rcv_nxt)
3839 *      Description
3840 *              Send out a tcp-ack. *tp* is the in-kernel struct **tcp_sock**.
3841 *              *rcv_nxt* is the ack_seq to be sent out.
3842 *      Return
3843 *              0 on success, or a negative error in case of failure.
3844 *
3845 * long bpf_send_signal_thread(u32 sig)
3846 *      Description
3847 *              Send signal *sig* to the thread corresponding to the current task.
3848 *      Return
3849 *              0 on success or successfully queued.
3850 *
3851 *              **-EBUSY** if work queue under nmi is full.
3852 *
3853 *              **-EINVAL** if *sig* is invalid.
3854 *
3855 *              **-EPERM** if no permission to send the *sig*.
3856 *
3857 *              **-EAGAIN** if bpf program can try again.
3858 *
3859 * u64 bpf_jiffies64(void)
3860 *      Description
3861 *              Obtain the 64bit jiffies
3862 *      Return
3863 *              The 64 bit jiffies
3864 *
3865 * long bpf_read_branch_records(struct bpf_perf_event_data *ctx, void *buf, u32 size, u64 flags)
3866 *      Description
3867 *              For an eBPF program attached to a perf event, retrieve the
3868 *              branch records (**struct perf_branch_entry**) associated to *ctx*
3869 *              and store it in the buffer pointed by *buf* up to size
3870 *              *size* bytes.
3871 *      Return
3872 *              On success, number of bytes written to *buf*. On error, a
3873 *              negative value.
3874 *
3875 *              The *flags* can be set to **BPF_F_GET_BRANCH_RECORDS_SIZE** to
3876 *              instead return the number of bytes required to store all the
3877 *              branch entries. If this flag is set, *buf* may be NULL.
3878 *
3879 *              **-EINVAL** if arguments invalid or **size** not a multiple
3880 *              of **sizeof**\ (**struct perf_branch_entry**\ ).
3881 *
3882 *              **-ENOENT** if architecture does not support branch records.
3883 *
3884 * long bpf_get_ns_current_pid_tgid(u64 dev, u64 ino, struct bpf_pidns_info *nsdata, u32 size)
3885 *      Description
3886 *              Returns 0 on success, values for *pid* and *tgid* as seen from the current
3887 *              *namespace* will be returned in *nsdata*.
3888 *      Return
3889 *              0 on success, or one of the following in case of failure:
3890 *
3891 *              **-EINVAL** if dev and inum supplied don't match dev_t and inode number
3892 *              with nsfs of current task, or if dev conversion to dev_t lost high bits.
3893 *
3894 *              **-ENOENT** if pidns does not exists for the current task.
3895 *
3896 * long bpf_xdp_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
3897 *      Description
3898 *              Write raw *data* blob into a special BPF perf event held by
3899 *              *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
3900 *              event must have the following attributes: **PERF_SAMPLE_RAW**
3901 *              as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
3902 *              **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
3903 *
3904 *              The *flags* are used to indicate the index in *map* for which
3905 *              the value must be put, masked with **BPF_F_INDEX_MASK**.
3906 *              Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
3907 *              to indicate that the index of the current CPU core should be
3908 *              used.
3909 *
3910 *              The value to write, of *size*, is passed through eBPF stack and
3911 *              pointed by *data*.
3912 *
3913 *              *ctx* is a pointer to in-kernel struct xdp_buff.
3914 *
3915 *              This helper is similar to **bpf_perf_eventoutput**\ () but
3916 *              restricted to raw_tracepoint bpf programs.
3917 *      Return
3918 *              0 on success, or a negative error in case of failure.
3919 *
3920 * u64 bpf_get_netns_cookie(void *ctx)
3921 *      Description
3922 *              Retrieve the cookie (generated by the kernel) of the network
3923 *              namespace the input *ctx* is associated with. The network
3924 *              namespace cookie remains stable for its lifetime and provides
3925 *              a global identifier that can be assumed unique. If *ctx* is
3926 *              NULL, then the helper returns the cookie for the initial
3927 *              network namespace. The cookie itself is very similar to that
3928 *              of **bpf_get_socket_cookie**\ () helper, but for network
3929 *              namespaces instead of sockets.
3930 *      Return
3931 *              A 8-byte long opaque number.
3932 *
3933 * u64 bpf_get_current_ancestor_cgroup_id(int ancestor_level)
3934 *      Description
3935 *              Return id of cgroup v2 that is ancestor of the cgroup associated
3936 *              with the current task at the *ancestor_level*. The root cgroup
3937 *              is at *ancestor_level* zero and each step down the hierarchy
3938 *              increments the level. If *ancestor_level* == level of cgroup
3939 *              associated with the current task, then return value will be the
3940 *              same as that of **bpf_get_current_cgroup_id**\ ().
3941 *
3942 *              The helper is useful to implement policies based on cgroups
3943 *              that are upper in hierarchy than immediate cgroup associated
3944 *              with the current task.
3945 *
3946 *              The format of returned id and helper limitations are same as in
3947 *              **bpf_get_current_cgroup_id**\ ().
3948 *      Return
3949 *              The id is returned or 0 in case the id could not be retrieved.
3950 *
3951 * long bpf_sk_assign(struct sk_buff *skb, void *sk, u64 flags)
3952 *      Description
3953 *              Helper is overloaded depending on BPF program type. This
3954 *              description applies to **BPF_PROG_TYPE_SCHED_CLS** and
3955 *              **BPF_PROG_TYPE_SCHED_ACT** programs.
3956 *
3957 *              Assign the *sk* to the *skb*. When combined with appropriate
3958 *              routing configuration to receive the packet towards the socket,
3959 *              will cause *skb* to be delivered to the specified socket.
3960 *              Subsequent redirection of *skb* via  **bpf_redirect**\ (),
3961 *              **bpf_clone_redirect**\ () or other methods outside of BPF may
3962 *              interfere with successful delivery to the socket.
3963 *
3964 *              This operation is only valid from TC ingress path.
3965 *
3966 *              The *flags* argument must be zero.
3967 *      Return
3968 *              0 on success, or a negative error in case of failure:
3969 *
3970 *              **-EINVAL** if specified *flags* are not supported.
3971 *
3972 *              **-ENOENT** if the socket is unavailable for assignment.
3973 *
3974 *              **-ENETUNREACH** if the socket is unreachable (wrong netns).
3975 *
3976 *              **-EOPNOTSUPP** if the operation is not supported, for example
3977 *              a call from outside of TC ingress.
3978 *
3979 *              **-ESOCKTNOSUPPORT** if the socket type is not supported
3980 *              (reuseport).
3981 *
3982 * long bpf_sk_assign(struct bpf_sk_lookup *ctx, struct bpf_sock *sk, u64 flags)
3983 *      Description
3984 *              Helper is overloaded depending on BPF program type. This
3985 *              description applies to **BPF_PROG_TYPE_SK_LOOKUP** programs.
3986 *
3987 *              Select the *sk* as a result of a socket lookup.
3988 *
3989 *              For the operation to succeed passed socket must be compatible
3990 *              with the packet description provided by the *ctx* object.
3991 *
3992 *              L4 protocol (**IPPROTO_TCP** or **IPPROTO_UDP**) must
3993 *              be an exact match. While IP family (**AF_INET** or
3994 *              **AF_INET6**) must be compatible, that is IPv6 sockets
3995 *              that are not v6-only can be selected for IPv4 packets.
3996 *
3997 *              Only TCP listeners and UDP unconnected sockets can be
3998 *              selected. *sk* can also be NULL to reset any previous
3999 *              selection.
4000 *
4001 *              *flags* argument can combination of following values:
4002 *
4003 *              * **BPF_SK_LOOKUP_F_REPLACE** to override the previous
4004 *                socket selection, potentially done by a BPF program
4005 *                that ran before us.
4006 *
4007 *              * **BPF_SK_LOOKUP_F_NO_REUSEPORT** to skip
4008 *                load-balancing within reuseport group for the socket
4009 *                being selected.
4010 *
4011 *              On success *ctx->sk* will point to the selected socket.
4012 *
4013 *      Return
4014 *              0 on success, or a negative errno in case of failure.
4015 *
4016 *              * **-EAFNOSUPPORT** if socket family (*sk->family*) is
4017 *                not compatible with packet family (*ctx->family*).
4018 *
4019 *              * **-EEXIST** if socket has been already selected,
4020 *                potentially by another program, and
4021 *                **BPF_SK_LOOKUP_F_REPLACE** flag was not specified.
4022 *
4023 *              * **-EINVAL** if unsupported flags were specified.
4024 *
4025 *              * **-EPROTOTYPE** if socket L4 protocol
4026 *                (*sk->protocol*) doesn't match packet protocol
4027 *                (*ctx->protocol*).
4028 *
4029 *              * **-ESOCKTNOSUPPORT** if socket is not in allowed
4030 *                state (TCP listening or UDP unconnected).
4031 *
4032 * u64 bpf_ktime_get_boot_ns(void)
4033 *      Description
4034 *              Return the time elapsed since system boot, in nanoseconds.
4035 *              Does include the time the system was suspended.
4036 *              See: **clock_gettime**\ (**CLOCK_BOOTTIME**)
4037 *      Return
4038 *              Current *ktime*.
4039 *
4040 * long bpf_seq_printf(struct seq_file *m, const char *fmt, u32 fmt_size, const void *data, u32 data_len)
4041 *      Description
4042 *              **bpf_seq_printf**\ () uses seq_file **seq_printf**\ () to print
4043 *              out the format string.
4044 *              The *m* represents the seq_file. The *fmt* and *fmt_size* are for
4045 *              the format string itself. The *data* and *data_len* are format string
4046 *              arguments. The *data* are a **u64** array and corresponding format string
4047 *              values are stored in the array. For strings and pointers where pointees
4048 *              are accessed, only the pointer values are stored in the *data* array.
4049 *              The *data_len* is the size of *data* in bytes.
4050 *
4051 *              Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory.
4052 *              Reading kernel memory may fail due to either invalid address or
4053 *              valid address but requiring a major memory fault. If reading kernel memory
4054 *              fails, the string for **%s** will be an empty string, and the ip
4055 *              address for **%p{i,I}{4,6}** will be 0. Not returning error to
4056 *              bpf program is consistent with what **bpf_trace_printk**\ () does for now.
4057 *      Return
4058 *              0 on success, or a negative error in case of failure:
4059 *
4060 *              **-EBUSY** if per-CPU memory copy buffer is busy, can try again
4061 *              by returning 1 from bpf program.
4062 *
4063 *              **-EINVAL** if arguments are invalid, or if *fmt* is invalid/unsupported.
4064 *
4065 *              **-E2BIG** if *fmt* contains too many format specifiers.
4066 *
4067 *              **-EOVERFLOW** if an overflow happened: The same object will be tried again.
4068 *
4069 * long bpf_seq_write(struct seq_file *m, const void *data, u32 len)
4070 *      Description
4071 *              **bpf_seq_write**\ () uses seq_file **seq_write**\ () to write the data.
4072 *              The *m* represents the seq_file. The *data* and *len* represent the
4073 *              data to write in bytes.
4074 *      Return
4075 *              0 on success, or a negative error in case of failure:
4076 *
4077 *              **-EOVERFLOW** if an overflow happened: The same object will be tried again.
4078 *
4079 * u64 bpf_sk_cgroup_id(void *sk)
4080 *      Description
4081 *              Return the cgroup v2 id of the socket *sk*.
4082 *
4083 *              *sk* must be a non-**NULL** pointer to a socket, e.g. one
4084 *              returned from **bpf_sk_lookup_xxx**\ (),
4085 *              **bpf_sk_fullsock**\ (), etc. The format of returned id is
4086 *              same as in **bpf_skb_cgroup_id**\ ().
4087 *
4088 *              This helper is available only if the kernel was compiled with
4089 *              the **CONFIG_SOCK_CGROUP_DATA** configuration option.
4090 *      Return
4091 *              The id is returned or 0 in case the id could not be retrieved.
4092 *
4093 * u64 bpf_sk_ancestor_cgroup_id(void *sk, int ancestor_level)
4094 *      Description
4095 *              Return id of cgroup v2 that is ancestor of cgroup associated
4096 *              with the *sk* at the *ancestor_level*.  The root cgroup is at
4097 *              *ancestor_level* zero and each step down the hierarchy
4098 *              increments the level. If *ancestor_level* == level of cgroup
4099 *              associated with *sk*, then return value will be same as that
4100 *              of **bpf_sk_cgroup_id**\ ().
4101 *
4102 *              The helper is useful to implement policies based on cgroups
4103 *              that are upper in hierarchy than immediate cgroup associated
4104 *              with *sk*.
4105 *
4106 *              The format of returned id and helper limitations are same as in
4107 *              **bpf_sk_cgroup_id**\ ().
4108 *      Return
4109 *              The id is returned or 0 in case the id could not be retrieved.
4110 *
4111 * long bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags)
4112 *      Description
4113 *              Copy *size* bytes from *data* into a ring buffer *ringbuf*.
4114 *              If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4115 *              of new data availability is sent.
4116 *              If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4117 *              of new data availability is sent unconditionally.
4118 *              If **0** is specified in *flags*, an adaptive notification
4119 *              of new data availability is sent.
4120 *
4121 *              An adaptive notification is a notification sent whenever the user-space
4122 *              process has caught up and consumed all available payloads. In case the user-space
4123 *              process is still processing a previous payload, then no notification is needed
4124 *              as it will process the newly added payload automatically.
4125 *      Return
4126 *              0 on success, or a negative error in case of failure.
4127 *
4128 * void *bpf_ringbuf_reserve(void *ringbuf, u64 size, u64 flags)
4129 *      Description
4130 *              Reserve *size* bytes of payload in a ring buffer *ringbuf*.
4131 *              *flags* must be 0.
4132 *      Return
4133 *              Valid pointer with *size* bytes of memory available; NULL,
4134 *              otherwise.
4135 *
4136 * void bpf_ringbuf_submit(void *data, u64 flags)
4137 *      Description
4138 *              Submit reserved ring buffer sample, pointed to by *data*.
4139 *              If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4140 *              of new data availability is sent.
4141 *              If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4142 *              of new data availability is sent unconditionally.
4143 *              If **0** is specified in *flags*, an adaptive notification
4144 *              of new data availability is sent.
4145 *
4146 *              See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4147 *      Return
4148 *              Nothing. Always succeeds.
4149 *
4150 * void bpf_ringbuf_discard(void *data, u64 flags)
4151 *      Description
4152 *              Discard reserved ring buffer sample, pointed to by *data*.
4153 *              If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4154 *              of new data availability is sent.
4155 *              If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4156 *              of new data availability is sent unconditionally.
4157 *              If **0** is specified in *flags*, an adaptive notification
4158 *              of new data availability is sent.
4159 *
4160 *              See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4161 *      Return
4162 *              Nothing. Always succeeds.
4163 *
4164 * u64 bpf_ringbuf_query(void *ringbuf, u64 flags)
4165 *      Description
4166 *              Query various characteristics of provided ring buffer. What
4167 *              exactly is queries is determined by *flags*:
4168 *
4169 *              * **BPF_RB_AVAIL_DATA**: Amount of data not yet consumed.
4170 *              * **BPF_RB_RING_SIZE**: The size of ring buffer.
4171 *              * **BPF_RB_CONS_POS**: Consumer position (can wrap around).
4172 *              * **BPF_RB_PROD_POS**: Producer(s) position (can wrap around).
4173 *
4174 *              Data returned is just a momentary snapshot of actual values
4175 *              and could be inaccurate, so this facility should be used to
4176 *              power heuristics and for reporting, not to make 100% correct
4177 *              calculation.
4178 *      Return
4179 *              Requested value, or 0, if *flags* are not recognized.
4180 *
4181 * long bpf_csum_level(struct sk_buff *skb, u64 level)
4182 *      Description
4183 *              Change the skbs checksum level by one layer up or down, or
4184 *              reset it entirely to none in order to have the stack perform
4185 *              checksum validation. The level is applicable to the following
4186 *              protocols: TCP, UDP, GRE, SCTP, FCOE. For example, a decap of
4187 *              | ETH | IP | UDP | GUE | IP | TCP | into | ETH | IP | TCP |
4188 *              through **bpf_skb_adjust_room**\ () helper with passing in
4189 *              **BPF_F_ADJ_ROOM_NO_CSUM_RESET** flag would require one call
4190 *              to **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_DEC** since
4191 *              the UDP header is removed. Similarly, an encap of the latter
4192 *              into the former could be accompanied by a helper call to
4193 *              **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_INC** if the
4194 *              skb is still intended to be processed in higher layers of the
4195 *              stack instead of just egressing at tc.
4196 *
4197 *              There are three supported level settings at this time:
4198 *
4199 *              * **BPF_CSUM_LEVEL_INC**: Increases skb->csum_level for skbs
4200 *                with CHECKSUM_UNNECESSARY.
4201 *              * **BPF_CSUM_LEVEL_DEC**: Decreases skb->csum_level for skbs
4202 *                with CHECKSUM_UNNECESSARY.
4203 *              * **BPF_CSUM_LEVEL_RESET**: Resets skb->csum_level to 0 and
4204 *                sets CHECKSUM_NONE to force checksum validation by the stack.
4205 *              * **BPF_CSUM_LEVEL_QUERY**: No-op, returns the current
4206 *                skb->csum_level.
4207 *      Return
4208 *              0 on success, or a negative error in case of failure. In the
4209 *              case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
4210 *              is returned or the error code -EACCES in case the skb is not
4211 *              subject to CHECKSUM_UNNECESSARY.
4212 *
4213 * struct tcp6_sock *bpf_skc_to_tcp6_sock(void *sk)
4214 *      Description
4215 *              Dynamically cast a *sk* pointer to a *tcp6_sock* pointer.
4216 *      Return
4217 *              *sk* if casting is valid, or **NULL** otherwise.
4218 *
4219 * struct tcp_sock *bpf_skc_to_tcp_sock(void *sk)
4220 *      Description
4221 *              Dynamically cast a *sk* pointer to a *tcp_sock* pointer.
4222 *      Return
4223 *              *sk* if casting is valid, or **NULL** otherwise.
4224 *
4225 * struct tcp_timewait_sock *bpf_skc_to_tcp_timewait_sock(void *sk)
4226 *      Description
4227 *              Dynamically cast a *sk* pointer to a *tcp_timewait_sock* pointer.
4228 *      Return
4229 *              *sk* if casting is valid, or **NULL** otherwise.
4230 *
4231 * struct tcp_request_sock *bpf_skc_to_tcp_request_sock(void *sk)
4232 *      Description
4233 *              Dynamically cast a *sk* pointer to a *tcp_request_sock* pointer.
4234 *      Return
4235 *              *sk* if casting is valid, or **NULL** otherwise.
4236 *
4237 * struct udp6_sock *bpf_skc_to_udp6_sock(void *sk)
4238 *      Description
4239 *              Dynamically cast a *sk* pointer to a *udp6_sock* pointer.
4240 *      Return
4241 *              *sk* if casting is valid, or **NULL** otherwise.
4242 *
4243 * long bpf_get_task_stack(struct task_struct *task, void *buf, u32 size, u64 flags)
4244 *      Description
4245 *              Return a user or a kernel stack in bpf program provided buffer.
4246 *              To achieve this, the helper needs *task*, which is a valid
4247 *              pointer to **struct task_struct**. To store the stacktrace, the
4248 *              bpf program provides *buf* with a nonnegative *size*.
4249 *
4250 *              The last argument, *flags*, holds the number of stack frames to
4251 *              skip (from 0 to 255), masked with
4252 *              **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
4253 *              the following flags:
4254 *
4255 *              **BPF_F_USER_STACK**
4256 *                      Collect a user space stack instead of a kernel stack.
4257 *              **BPF_F_USER_BUILD_ID**
4258 *                      Collect buildid+offset instead of ips for user stack,
4259 *                      only valid if **BPF_F_USER_STACK** is also specified.
4260 *
4261 *              **bpf_get_task_stack**\ () can collect up to
4262 *              **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
4263 *              to sufficient large buffer size. Note that
4264 *              this limit can be controlled with the **sysctl** program, and
4265 *              that it should be manually increased in order to profile long
4266 *              user stacks (such as stacks for Java programs). To do so, use:
4267 *
4268 *              ::
4269 *
4270 *                      # sysctl kernel.perf_event_max_stack=<new value>
4271 *      Return
4272 *              A non-negative value equal to or less than *size* on success,
4273 *              or a negative error in case of failure.
4274 *
4275 * long bpf_load_hdr_opt(struct bpf_sock_ops *skops, void *searchby_res, u32 len, u64 flags)
4276 *      Description
4277 *              Load header option.  Support reading a particular TCP header
4278 *              option for bpf program (**BPF_PROG_TYPE_SOCK_OPS**).
4279 *
4280 *              If *flags* is 0, it will search the option from the
4281 *              *skops*\ **->skb_data**.  The comment in **struct bpf_sock_ops**
4282 *              has details on what skb_data contains under different
4283 *              *skops*\ **->op**.
4284 *
4285 *              The first byte of the *searchby_res* specifies the
4286 *              kind that it wants to search.
4287 *
4288 *              If the searching kind is an experimental kind
4289 *              (i.e. 253 or 254 according to RFC6994).  It also
4290 *              needs to specify the "magic" which is either
4291 *              2 bytes or 4 bytes.  It then also needs to
4292 *              specify the size of the magic by using
4293 *              the 2nd byte which is "kind-length" of a TCP
4294 *              header option and the "kind-length" also
4295 *              includes the first 2 bytes "kind" and "kind-length"
4296 *              itself as a normal TCP header option also does.
4297 *
4298 *              For example, to search experimental kind 254 with
4299 *              2 byte magic 0xeB9F, the searchby_res should be
4300 *              [ 254, 4, 0xeB, 0x9F, 0, 0, .... 0 ].
4301 *
4302 *              To search for the standard window scale option (3),
4303 *              the *searchby_res* should be [ 3, 0, 0, .... 0 ].
4304 *              Note, kind-length must be 0 for regular option.
4305 *
4306 *              Searching for No-Op (0) and End-of-Option-List (1) are
4307 *              not supported.
4308 *
4309 *              *len* must be at least 2 bytes which is the minimal size
4310 *              of a header option.
4311 *
4312 *              Supported flags:
4313 *
4314 *              * **BPF_LOAD_HDR_OPT_TCP_SYN** to search from the
4315 *                saved_syn packet or the just-received syn packet.
4316 *
4317 *      Return
4318 *              > 0 when found, the header option is copied to *searchby_res*.
4319 *              The return value is the total length copied. On failure, a
4320 *              negative error code is returned:
4321 *
4322 *              **-EINVAL** if a parameter is invalid.
4323 *
4324 *              **-ENOMSG** if the option is not found.
4325 *
4326 *              **-ENOENT** if no syn packet is available when
4327 *              **BPF_LOAD_HDR_OPT_TCP_SYN** is used.
4328 *
4329 *              **-ENOSPC** if there is not enough space.  Only *len* number of
4330 *              bytes are copied.
4331 *
4332 *              **-EFAULT** on failure to parse the header options in the
4333 *              packet.
4334 *
4335 *              **-EPERM** if the helper cannot be used under the current
4336 *              *skops*\ **->op**.
4337 *
4338 * long bpf_store_hdr_opt(struct bpf_sock_ops *skops, const void *from, u32 len, u64 flags)
4339 *      Description
4340 *              Store header option.  The data will be copied
4341 *              from buffer *from* with length *len* to the TCP header.
4342 *
4343 *              The buffer *from* should have the whole option that
4344 *              includes the kind, kind-length, and the actual
4345 *              option data.  The *len* must be at least kind-length
4346 *              long.  The kind-length does not have to be 4 byte
4347 *              aligned.  The kernel will take care of the padding
4348 *              and setting the 4 bytes aligned value to th->doff.
4349 *
4350 *              This helper will check for duplicated option
4351 *              by searching the same option in the outgoing skb.
4352 *
4353 *              This helper can only be called during
4354 *              **BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
4355 *
4356 *      Return
4357 *              0 on success, or negative error in case of failure:
4358 *
4359 *              **-EINVAL** If param is invalid.
4360 *
4361 *              **-ENOSPC** if there is not enough space in the header.
4362 *              Nothing has been written
4363 *
4364 *              **-EEXIST** if the option already exists.
4365 *
4366 *              **-EFAULT** on failrue to parse the existing header options.
4367 *
4368 *              **-EPERM** if the helper cannot be used under the current
4369 *              *skops*\ **->op**.
4370 *
4371 * long bpf_reserve_hdr_opt(struct bpf_sock_ops *skops, u32 len, u64 flags)
4372 *      Description
4373 *              Reserve *len* bytes for the bpf header option.  The
4374 *              space will be used by **bpf_store_hdr_opt**\ () later in
4375 *              **BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
4376 *
4377 *              If **bpf_reserve_hdr_opt**\ () is called multiple times,
4378 *              the total number of bytes will be reserved.
4379 *
4380 *              This helper can only be called during
4381 *              **BPF_SOCK_OPS_HDR_OPT_LEN_CB**.
4382 *
4383 *      Return
4384 *              0 on success, or negative error in case of failure:
4385 *
4386 *              **-EINVAL** if a parameter is invalid.
4387 *
4388 *              **-ENOSPC** if there is not enough space in the header.
4389 *
4390 *              **-EPERM** if the helper cannot be used under the current
4391 *              *skops*\ **->op**.
4392 *
4393 * void *bpf_inode_storage_get(struct bpf_map *map, void *inode, void *value, u64 flags)
4394 *      Description
4395 *              Get a bpf_local_storage from an *inode*.
4396 *
4397 *              Logically, it could be thought of as getting the value from
4398 *              a *map* with *inode* as the **key**.  From this
4399 *              perspective,  the usage is not much different from
4400 *              **bpf_map_lookup_elem**\ (*map*, **&**\ *inode*) except this
4401 *              helper enforces the key must be an inode and the map must also
4402 *              be a **BPF_MAP_TYPE_INODE_STORAGE**.
4403 *
4404 *              Underneath, the value is stored locally at *inode* instead of
4405 *              the *map*.  The *map* is used as the bpf-local-storage
4406 *              "type". The bpf-local-storage "type" (i.e. the *map*) is
4407 *              searched against all bpf_local_storage residing at *inode*.
4408 *
4409 *              An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
4410 *              used such that a new bpf_local_storage will be
4411 *              created if one does not exist.  *value* can be used
4412 *              together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
4413 *              the initial value of a bpf_local_storage.  If *value* is
4414 *              **NULL**, the new bpf_local_storage will be zero initialized.
4415 *      Return
4416 *              A bpf_local_storage pointer is returned on success.
4417 *
4418 *              **NULL** if not found or there was an error in adding
4419 *              a new bpf_local_storage.
4420 *
4421 * int bpf_inode_storage_delete(struct bpf_map *map, void *inode)
4422 *      Description
4423 *              Delete a bpf_local_storage from an *inode*.
4424 *      Return
4425 *              0 on success.
4426 *
4427 *              **-ENOENT** if the bpf_local_storage cannot be found.
4428 *
4429 * long bpf_d_path(struct path *path, char *buf, u32 sz)
4430 *      Description
4431 *              Return full path for given **struct path** object, which
4432 *              needs to be the kernel BTF *path* object. The path is
4433 *              returned in the provided buffer *buf* of size *sz* and
4434 *              is zero terminated.
4435 *
4436 *      Return
4437 *              On success, the strictly positive length of the string,
4438 *              including the trailing NUL character. On error, a negative
4439 *              value.
4440 *
4441 * long bpf_copy_from_user(void *dst, u32 size, const void *user_ptr)
4442 *      Description
4443 *              Read *size* bytes from user space address *user_ptr* and store
4444 *              the data in *dst*. This is a wrapper of **copy_from_user**\ ().
4445 *      Return
4446 *              0 on success, or a negative error in case of failure.
4447 *
4448 * long bpf_snprintf_btf(char *str, u32 str_size, struct btf_ptr *ptr, u32 btf_ptr_size, u64 flags)
4449 *      Description
4450 *              Use BTF to store a string representation of *ptr*->ptr in *str*,
4451 *              using *ptr*->type_id.  This value should specify the type
4452 *              that *ptr*->ptr points to. LLVM __builtin_btf_type_id(type, 1)
4453 *              can be used to look up vmlinux BTF type ids. Traversing the
4454 *              data structure using BTF, the type information and values are
4455 *              stored in the first *str_size* - 1 bytes of *str*.  Safe copy of
4456 *              the pointer data is carried out to avoid kernel crashes during
4457 *              operation.  Smaller types can use string space on the stack;
4458 *              larger programs can use map data to store the string
4459 *              representation.
4460 *
4461 *              The string can be subsequently shared with userspace via
4462 *              bpf_perf_event_output() or ring buffer interfaces.
4463 *              bpf_trace_printk() is to be avoided as it places too small
4464 *              a limit on string size to be useful.
4465 *
4466 *              *flags* is a combination of
4467 *
4468 *              **BTF_F_COMPACT**
4469 *                      no formatting around type information
4470 *              **BTF_F_NONAME**
4471 *                      no struct/union member names/types
4472 *              **BTF_F_PTR_RAW**
4473 *                      show raw (unobfuscated) pointer values;
4474 *                      equivalent to printk specifier %px.
4475 *              **BTF_F_ZERO**
4476 *                      show zero-valued struct/union members; they
4477 *                      are not displayed by default
4478 *
4479 *      Return
4480 *              The number of bytes that were written (or would have been
4481 *              written if output had to be truncated due to string size),
4482 *              or a negative error in cases of failure.
4483 *
4484 * long bpf_seq_printf_btf(struct seq_file *m, struct btf_ptr *ptr, u32 ptr_size, u64 flags)
4485 *      Description
4486 *              Use BTF to write to seq_write a string representation of
4487 *              *ptr*->ptr, using *ptr*->type_id as per bpf_snprintf_btf().
4488 *              *flags* are identical to those used for bpf_snprintf_btf.
4489 *      Return
4490 *              0 on success or a negative error in case of failure.
4491 *
4492 * u64 bpf_skb_cgroup_classid(struct sk_buff *skb)
4493 *      Description
4494 *              See **bpf_get_cgroup_classid**\ () for the main description.
4495 *              This helper differs from **bpf_get_cgroup_classid**\ () in that
4496 *              the cgroup v1 net_cls class is retrieved only from the *skb*'s
4497 *              associated socket instead of the current process.
4498 *      Return
4499 *              The id is returned or 0 in case the id could not be retrieved.
4500 *
4501 * long bpf_redirect_neigh(u32 ifindex, struct bpf_redir_neigh *params, int plen, u64 flags)
4502 *      Description
4503 *              Redirect the packet to another net device of index *ifindex*
4504 *              and fill in L2 addresses from neighboring subsystem. This helper
4505 *              is somewhat similar to **bpf_redirect**\ (), except that it
4506 *              populates L2 addresses as well, meaning, internally, the helper
4507 *              relies on the neighbor lookup for the L2 address of the nexthop.
4508 *
4509 *              The helper will perform a FIB lookup based on the skb's
4510 *              networking header to get the address of the next hop, unless
4511 *              this is supplied by the caller in the *params* argument. The
4512 *              *plen* argument indicates the len of *params* and should be set
4513 *              to 0 if *params* is NULL.
4514 *
4515 *              The *flags* argument is reserved and must be 0. The helper is
4516 *              currently only supported for tc BPF program types, and enabled
4517 *              for IPv4 and IPv6 protocols.
4518 *      Return
4519 *              The helper returns **TC_ACT_REDIRECT** on success or
4520 *              **TC_ACT_SHOT** on error.
4521 *
4522 * void *bpf_per_cpu_ptr(const void *percpu_ptr, u32 cpu)
4523 *     Description
4524 *             Take a pointer to a percpu ksym, *percpu_ptr*, and return a
4525 *             pointer to the percpu kernel variable on *cpu*. A ksym is an
4526 *             extern variable decorated with '__ksym'. For ksym, there is a
4527 *             global var (either static or global) defined of the same name
4528 *             in the kernel. The ksym is percpu if the global var is percpu.
4529 *             The returned pointer points to the global percpu var on *cpu*.
4530 *
4531 *             bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the
4532 *             kernel, except that bpf_per_cpu_ptr() may return NULL. This
4533 *             happens if *cpu* is larger than nr_cpu_ids. The caller of
4534 *             bpf_per_cpu_ptr() must check the returned value.
4535 *     Return
4536 *             A pointer pointing to the kernel percpu variable on *cpu*, or
4537 *             NULL, if *cpu* is invalid.
4538 *
4539 * void *bpf_this_cpu_ptr(const void *percpu_ptr)
4540 *      Description
4541 *              Take a pointer to a percpu ksym, *percpu_ptr*, and return a
4542 *              pointer to the percpu kernel variable on this cpu. See the
4543 *              description of 'ksym' in **bpf_per_cpu_ptr**\ ().
4544 *
4545 *              bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in
4546 *              the kernel. Different from **bpf_per_cpu_ptr**\ (), it would
4547 *              never return NULL.
4548 *      Return
4549 *              A pointer pointing to the kernel percpu variable on this cpu.
4550 *
4551 * long bpf_redirect_peer(u32 ifindex, u64 flags)
4552 *      Description
4553 *              Redirect the packet to another net device of index *ifindex*.
4554 *              This helper is somewhat similar to **bpf_redirect**\ (), except
4555 *              that the redirection happens to the *ifindex*' peer device and
4556 *              the netns switch takes place from ingress to ingress without
4557 *              going through the CPU's backlog queue.
4558 *
4559 *              The *flags* argument is reserved and must be 0. The helper is
4560 *              currently only supported for tc BPF program types at the ingress
4561 *              hook and for veth device types. The peer device must reside in a
4562 *              different network namespace.
4563 *      Return
4564 *              The helper returns **TC_ACT_REDIRECT** on success or
4565 *              **TC_ACT_SHOT** on error.
4566 *
4567 * void *bpf_task_storage_get(struct bpf_map *map, struct task_struct *task, void *value, u64 flags)
4568 *      Description
4569 *              Get a bpf_local_storage from the *task*.
4570 *
4571 *              Logically, it could be thought of as getting the value from
4572 *              a *map* with *task* as the **key**.  From this
4573 *              perspective,  the usage is not much different from
4574 *              **bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this
4575 *              helper enforces the key must be an task_struct and the map must also
4576 *              be a **BPF_MAP_TYPE_TASK_STORAGE**.
4577 *
4578 *              Underneath, the value is stored locally at *task* instead of
4579 *              the *map*.  The *map* is used as the bpf-local-storage
4580 *              "type". The bpf-local-storage "type" (i.e. the *map*) is
4581 *              searched against all bpf_local_storage residing at *task*.
4582 *
4583 *              An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
4584 *              used such that a new bpf_local_storage will be
4585 *              created if one does not exist.  *value* can be used
4586 *              together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
4587 *              the initial value of a bpf_local_storage.  If *value* is
4588 *              **NULL**, the new bpf_local_storage will be zero initialized.
4589 *      Return
4590 *              A bpf_local_storage pointer is returned on success.
4591 *
4592 *              **NULL** if not found or there was an error in adding
4593 *              a new bpf_local_storage.
4594 *
4595 * long bpf_task_storage_delete(struct bpf_map *map, struct task_struct *task)
4596 *      Description
4597 *              Delete a bpf_local_storage from a *task*.
4598 *      Return
4599 *              0 on success.
4600 *
4601 *              **-ENOENT** if the bpf_local_storage cannot be found.
4602 *
4603 * struct task_struct *bpf_get_current_task_btf(void)
4604 *      Description
4605 *              Return a BTF pointer to the "current" task.
4606 *              This pointer can also be used in helpers that accept an
4607 *              *ARG_PTR_TO_BTF_ID* of type *task_struct*.
4608 *      Return
4609 *              Pointer to the current task.
4610 *
4611 * long bpf_bprm_opts_set(struct linux_binprm *bprm, u64 flags)
4612 *      Description
4613 *              Set or clear certain options on *bprm*:
4614 *
4615 *              **BPF_F_BPRM_SECUREEXEC** Set the secureexec bit
4616 *              which sets the **AT_SECURE** auxv for glibc. The bit
4617 *              is cleared if the flag is not specified.
4618 *      Return
4619 *              **-EINVAL** if invalid *flags* are passed, zero otherwise.
4620 *
4621 * u64 bpf_ktime_get_coarse_ns(void)
4622 *      Description
4623 *              Return a coarse-grained version of the time elapsed since
4624 *              system boot, in nanoseconds. Does not include time the system
4625 *              was suspended.
4626 *
4627 *              See: **clock_gettime**\ (**CLOCK_MONOTONIC_COARSE**)
4628 *      Return
4629 *              Current *ktime*.
4630 *
4631 * long bpf_ima_inode_hash(struct inode *inode, void *dst, u32 size)
4632 *      Description
4633 *              Returns the stored IMA hash of the *inode* (if it's avaialable).
4634 *              If the hash is larger than *size*, then only *size*
4635 *              bytes will be copied to *dst*
4636 *      Return
4637 *              The **hash_algo** is returned on success,
4638 *              **-EOPNOTSUP** if IMA is disabled or **-EINVAL** if
4639 *              invalid arguments are passed.
4640 *
4641 * struct socket *bpf_sock_from_file(struct file *file)
4642 *      Description
4643 *              If the given file represents a socket, returns the associated
4644 *              socket.
4645 *      Return
4646 *              A pointer to a struct socket on success or NULL if the file is
4647 *              not a socket.
4648 *
4649 * long bpf_check_mtu(void *ctx, u32 ifindex, u32 *mtu_len, s32 len_diff, u64 flags)
4650 *      Description
4651 *              Check packet size against exceeding MTU of net device (based
4652 *              on *ifindex*).  This helper will likely be used in combination
4653 *              with helpers that adjust/change the packet size.
4654 *
4655 *              The argument *len_diff* can be used for querying with a planned
4656 *              size change. This allows to check MTU prior to changing packet
4657 *              ctx. Providing an *len_diff* adjustment that is larger than the
4658 *              actual packet size (resulting in negative packet size) will in
4659 *              principle not exceed the MTU, why it is not considered a
4660 *              failure.  Other BPF-helpers are needed for performing the
4661 *              planned size change, why the responsability for catch a negative
4662 *              packet size belong in those helpers.
4663 *
4664 *              Specifying *ifindex* zero means the MTU check is performed
4665 *              against the current net device.  This is practical if this isn't
4666 *              used prior to redirect.
4667 *
4668 *              On input *mtu_len* must be a valid pointer, else verifier will
4669 *              reject BPF program.  If the value *mtu_len* is initialized to
4670 *              zero then the ctx packet size is use.  When value *mtu_len* is
4671 *              provided as input this specify the L3 length that the MTU check
4672 *              is done against. Remember XDP and TC length operate at L2, but
4673 *              this value is L3 as this correlate to MTU and IP-header tot_len
4674 *              values which are L3 (similar behavior as bpf_fib_lookup).
4675 *
4676 *              The Linux kernel route table can configure MTUs on a more
4677 *              specific per route level, which is not provided by this helper.
4678 *              For route level MTU checks use the **bpf_fib_lookup**\ ()
4679 *              helper.
4680 *
4681 *              *ctx* is either **struct xdp_md** for XDP programs or
4682 *              **struct sk_buff** for tc cls_act programs.
4683 *
4684 *              The *flags* argument can be a combination of one or more of the
4685 *              following values:
4686 *
4687 *              **BPF_MTU_CHK_SEGS**
4688 *                      This flag will only works for *ctx* **struct sk_buff**.
4689 *                      If packet context contains extra packet segment buffers
4690 *                      (often knows as GSO skb), then MTU check is harder to
4691 *                      check at this point, because in transmit path it is
4692 *                      possible for the skb packet to get re-segmented
4693 *                      (depending on net device features).  This could still be
4694 *                      a MTU violation, so this flag enables performing MTU
4695 *                      check against segments, with a different violation
4696 *                      return code to tell it apart. Check cannot use len_diff.
4697 *
4698 *              On return *mtu_len* pointer contains the MTU value of the net
4699 *              device.  Remember the net device configured MTU is the L3 size,
4700 *              which is returned here and XDP and TC length operate at L2.
4701 *              Helper take this into account for you, but remember when using
4702 *              MTU value in your BPF-code.
4703 *
4704 *      Return
4705 *              * 0 on success, and populate MTU value in *mtu_len* pointer.
4706 *
4707 *              * < 0 if any input argument is invalid (*mtu_len* not updated)
4708 *
4709 *              MTU violations return positive values, but also populate MTU
4710 *              value in *mtu_len* pointer, as this can be needed for
4711 *              implementing PMTU handing:
4712 *
4713 *              * **BPF_MTU_CHK_RET_FRAG_NEEDED**
4714 *              * **BPF_MTU_CHK_RET_SEGS_TOOBIG**
4715 *
4716 * long bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn, void *callback_ctx, u64 flags)
4717 *      Description
4718 *              For each element in **map**, call **callback_fn** function with
4719 *              **map**, **callback_ctx** and other map-specific parameters.
4720 *              The **callback_fn** should be a static function and
4721 *              the **callback_ctx** should be a pointer to the stack.
4722 *              The **flags** is used to control certain aspects of the helper.
4723 *              Currently, the **flags** must be 0.
4724 *
4725 *              The following are a list of supported map types and their
4726 *              respective expected callback signatures:
4727 *
4728 *              BPF_MAP_TYPE_HASH, BPF_MAP_TYPE_PERCPU_HASH,
4729 *              BPF_MAP_TYPE_LRU_HASH, BPF_MAP_TYPE_LRU_PERCPU_HASH,
4730 *              BPF_MAP_TYPE_ARRAY, BPF_MAP_TYPE_PERCPU_ARRAY
4731 *
4732 *              long (\*callback_fn)(struct bpf_map \*map, const void \*key, void \*value, void \*ctx);
4733 *
4734 *              For per_cpu maps, the map_value is the value on the cpu where the
4735 *              bpf_prog is running.
4736 *
4737 *              If **callback_fn** return 0, the helper will continue to the next
4738 *              element. If return value is 1, the helper will skip the rest of
4739 *              elements and return. Other return values are not used now.
4740 *
4741 *      Return
4742 *              The number of traversed map elements for success, **-EINVAL** for
4743 *              invalid **flags**.
4744 *
4745 * long bpf_snprintf(char *str, u32 str_size, const char *fmt, u64 *data, u32 data_len)
4746 *      Description
4747 *              Outputs a string into the **str** buffer of size **str_size**
4748 *              based on a format string stored in a read-only map pointed by
4749 *              **fmt**.
4750 *
4751 *              Each format specifier in **fmt** corresponds to one u64 element
4752 *              in the **data** array. For strings and pointers where pointees
4753 *              are accessed, only the pointer values are stored in the *data*
4754 *              array. The *data_len* is the size of *data* in bytes.
4755 *
4756 *              Formats **%s** and **%p{i,I}{4,6}** require to read kernel
4757 *              memory. Reading kernel memory may fail due to either invalid
4758 *              address or valid address but requiring a major memory fault. If
4759 *              reading kernel memory fails, the string for **%s** will be an
4760 *              empty string, and the ip address for **%p{i,I}{4,6}** will be 0.
4761 *              Not returning error to bpf program is consistent with what
4762 *              **bpf_trace_printk**\ () does for now.
4763 *
4764 *      Return
4765 *              The strictly positive length of the formatted string, including
4766 *              the trailing zero character. If the return value is greater than
4767 *              **str_size**, **str** contains a truncated string, guaranteed to
4768 *              be zero-terminated except when **str_size** is 0.
4769 *
4770 *              Or **-EBUSY** if the per-CPU memory copy buffer is busy.
4771 *
4772 * long bpf_sys_bpf(u32 cmd, void *attr, u32 attr_size)
4773 *      Description
4774 *              Execute bpf syscall with given arguments.
4775 *      Return
4776 *              A syscall result.
4777 *
4778 * long bpf_btf_find_by_name_kind(char *name, int name_sz, u32 kind, int flags)
4779 *      Description
4780 *              Find BTF type with given name and kind in vmlinux BTF or in module's BTFs.
4781 *      Return
4782 *              Returns btf_id and btf_obj_fd in lower and upper 32 bits.
4783 *
4784 * long bpf_sys_close(u32 fd)
4785 *      Description
4786 *              Execute close syscall for given FD.
4787 *      Return
4788 *              A syscall result.
4789 *
4790 * long bpf_timer_init(struct bpf_timer *timer, struct bpf_map *map, u64 flags)
4791 *      Description
4792 *              Initialize the timer.
4793 *              First 4 bits of *flags* specify clockid.
4794 *              Only CLOCK_MONOTONIC, CLOCK_REALTIME, CLOCK_BOOTTIME are allowed.
4795 *              All other bits of *flags* are reserved.
4796 *              The verifier will reject the program if *timer* is not from
4797 *              the same *map*.
4798 *      Return
4799 *              0 on success.
4800 *              **-EBUSY** if *timer* is already initialized.
4801 *              **-EINVAL** if invalid *flags* are passed.
4802 *              **-EPERM** if *timer* is in a map that doesn't have any user references.
4803 *              The user space should either hold a file descriptor to a map with timers
4804 *              or pin such map in bpffs. When map is unpinned or file descriptor is
4805 *              closed all timers in the map will be cancelled and freed.
4806 *
4807 * long bpf_timer_set_callback(struct bpf_timer *timer, void *callback_fn)
4808 *      Description
4809 *              Configure the timer to call *callback_fn* static function.
4810 *      Return
4811 *              0 on success.
4812 *              **-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
4813 *              **-EPERM** if *timer* is in a map that doesn't have any user references.
4814 *              The user space should either hold a file descriptor to a map with timers
4815 *              or pin such map in bpffs. When map is unpinned or file descriptor is
4816 *              closed all timers in the map will be cancelled and freed.
4817 *
4818 * long bpf_timer_start(struct bpf_timer *timer, u64 nsecs, u64 flags)
4819 *      Description
4820 *              Set timer expiration N nanoseconds from the current time. The
4821 *              configured callback will be invoked in soft irq context on some cpu
4822 *              and will not repeat unless another bpf_timer_start() is made.
4823 *              In such case the next invocation can migrate to a different cpu.
4824 *              Since struct bpf_timer is a field inside map element the map
4825 *              owns the timer. The bpf_timer_set_callback() will increment refcnt
4826 *              of BPF program to make sure that callback_fn code stays valid.
4827 *              When user space reference to a map reaches zero all timers
4828 *              in a map are cancelled and corresponding program's refcnts are
4829 *              decremented. This is done to make sure that Ctrl-C of a user
4830 *              process doesn't leave any timers running. If map is pinned in
4831 *              bpffs the callback_fn can re-arm itself indefinitely.
4832 *              bpf_map_update/delete_elem() helpers and user space sys_bpf commands
4833 *              cancel and free the timer in the given map element.
4834 *              The map can contain timers that invoke callback_fn-s from different
4835 *              programs. The same callback_fn can serve different timers from
4836 *              different maps if key/value layout matches across maps.
4837 *              Every bpf_timer_set_callback() can have different callback_fn.
4838 *
4839 *      Return
4840 *              0 on success.
4841 *              **-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier
4842 *              or invalid *flags* are passed.
4843 *
4844 * long bpf_timer_cancel(struct bpf_timer *timer)
4845 *      Description
4846 *              Cancel the timer and wait for callback_fn to finish if it was running.
4847 *      Return
4848 *              0 if the timer was not active.
4849 *              1 if the timer was active.
4850 *              **-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
4851 *              **-EDEADLK** if callback_fn tried to call bpf_timer_cancel() on its
4852 *              own timer which would have led to a deadlock otherwise.
4853 *
4854 * u64 bpf_get_func_ip(void *ctx)
4855 *      Description
4856 *              Get address of the traced function (for tracing and kprobe programs).
4857 *      Return
4858 *              Address of the traced function.
4859 *
4860 * u64 bpf_get_attach_cookie(void *ctx)
4861 *      Description
4862 *              Get bpf_cookie value provided (optionally) during the program
4863 *              attachment. It might be different for each individual
4864 *              attachment, even if BPF program itself is the same.
4865 *              Expects BPF program context *ctx* as a first argument.
4866 *
4867 *              Supported for the following program types:
4868 *                      - kprobe/uprobe;
4869 *                      - tracepoint;
4870 *                      - perf_event.
4871 *      Return
4872 *              Value specified by user at BPF link creation/attachment time
4873 *              or 0, if it was not specified.
4874 *
4875 * long bpf_task_pt_regs(struct task_struct *task)
4876 *      Description
4877 *              Get the struct pt_regs associated with **task**.
4878 *      Return
4879 *              A pointer to struct pt_regs.
4880 */
4881#define __BPF_FUNC_MAPPER(FN)           \
4882        FN(unspec),                     \
4883        FN(map_lookup_elem),            \
4884        FN(map_update_elem),            \
4885        FN(map_delete_elem),            \
4886        FN(probe_read),                 \
4887        FN(ktime_get_ns),               \
4888        FN(trace_printk),               \
4889        FN(get_prandom_u32),            \
4890        FN(get_smp_processor_id),       \
4891        FN(skb_store_bytes),            \
4892        FN(l3_csum_replace),            \
4893        FN(l4_csum_replace),            \
4894        FN(tail_call),                  \
4895        FN(clone_redirect),             \
4896        FN(get_current_pid_tgid),       \
4897        FN(get_current_uid_gid),        \
4898        FN(get_current_comm),           \
4899        FN(get_cgroup_classid),         \
4900        FN(skb_vlan_push),              \
4901        FN(skb_vlan_pop),               \
4902        FN(skb_get_tunnel_key),         \
4903        FN(skb_set_tunnel_key),         \
4904        FN(perf_event_read),            \
4905        FN(redirect),                   \
4906        FN(get_route_realm),            \
4907        FN(perf_event_output),          \
4908        FN(skb_load_bytes),             \
4909        FN(get_stackid),                \
4910        FN(csum_diff),                  \
4911        FN(skb_get_tunnel_opt),         \
4912        FN(skb_set_tunnel_opt),         \
4913        FN(skb_change_proto),           \
4914        FN(skb_change_type),            \
4915        FN(skb_under_cgroup),           \
4916        FN(get_hash_recalc),            \
4917        FN(get_current_task),           \
4918        FN(probe_write_user),           \
4919        FN(current_task_under_cgroup),  \
4920        FN(skb_change_tail),            \
4921        FN(skb_pull_data),              \
4922        FN(csum_update),                \
4923        FN(set_hash_invalid),           \
4924        FN(get_numa_node_id),           \
4925        FN(skb_change_head),            \
4926        FN(xdp_adjust_head),            \
4927        FN(probe_read_str),             \
4928        FN(get_socket_cookie),          \
4929        FN(get_socket_uid),             \
4930        FN(set_hash),                   \
4931        FN(setsockopt),                 \
4932        FN(skb_adjust_room),            \
4933        FN(redirect_map),               \
4934        FN(sk_redirect_map),            \
4935        FN(sock_map_update),            \
4936        FN(xdp_adjust_meta),            \
4937        FN(perf_event_read_value),      \
4938        FN(perf_prog_read_value),       \
4939        FN(getsockopt),                 \
4940        FN(override_return),            \
4941        FN(sock_ops_cb_flags_set),      \
4942        FN(msg_redirect_map),           \
4943        FN(msg_apply_bytes),            \
4944        FN(msg_cork_bytes),             \
4945        FN(msg_pull_data),              \
4946        FN(bind),                       \
4947        FN(xdp_adjust_tail),            \
4948        FN(skb_get_xfrm_state),         \
4949        FN(get_stack),                  \
4950        FN(skb_load_bytes_relative),    \
4951        FN(fib_lookup),                 \
4952        FN(sock_hash_update),           \
4953        FN(msg_redirect_hash),          \
4954        FN(sk_redirect_hash),           \
4955        FN(lwt_push_encap),             \
4956        FN(lwt_seg6_store_bytes),       \
4957        FN(lwt_seg6_adjust_srh),        \
4958        FN(lwt_seg6_action),            \
4959        FN(rc_repeat),                  \
4960        FN(rc_keydown),                 \
4961        FN(skb_cgroup_id),              \
4962        FN(get_current_cgroup_id),      \
4963        FN(get_local_storage),          \
4964        FN(sk_select_reuseport),        \
4965        FN(skb_ancestor_cgroup_id),     \
4966        FN(sk_lookup_tcp),              \
4967        FN(sk_lookup_udp),              \
4968        FN(sk_release),                 \
4969        FN(map_push_elem),              \
4970        FN(map_pop_elem),               \
4971        FN(map_peek_elem),              \
4972        FN(msg_push_data),              \
4973        FN(msg_pop_data),               \
4974        FN(rc_pointer_rel),             \
4975        FN(spin_lock),                  \
4976        FN(spin_unlock),                \
4977        FN(sk_fullsock),                \
4978        FN(tcp_sock),                   \
4979        FN(skb_ecn_set_ce),             \
4980        FN(get_listener_sock),          \
4981        FN(skc_lookup_tcp),             \
4982        FN(tcp_check_syncookie),        \
4983        FN(sysctl_get_name),            \
4984        FN(sysctl_get_current_value),   \
4985        FN(sysctl_get_new_value),       \
4986        FN(sysctl_set_new_value),       \
4987        FN(strtol),                     \
4988        FN(strtoul),                    \
4989        FN(sk_storage_get),             \
4990        FN(sk_storage_delete),          \
4991        FN(send_signal),                \
4992        FN(tcp_gen_syncookie),          \
4993        FN(skb_output),                 \
4994        FN(probe_read_user),            \
4995        FN(probe_read_kernel),          \
4996        FN(probe_read_user_str),        \
4997        FN(probe_read_kernel_str),      \
4998        FN(tcp_send_ack),               \
4999        FN(send_signal_thread),         \
5000        FN(jiffies64),                  \
5001        FN(read_branch_records),        \
5002        FN(get_ns_current_pid_tgid),    \
5003        FN(xdp_output),                 \
5004        FN(get_netns_cookie),           \
5005        FN(get_current_ancestor_cgroup_id),     \
5006        FN(sk_assign),                  \
5007        FN(ktime_get_boot_ns),          \
5008        FN(seq_printf),                 \
5009        FN(seq_write),                  \
5010        FN(sk_cgroup_id),               \
5011        FN(sk_ancestor_cgroup_id),      \
5012        FN(ringbuf_output),             \
5013        FN(ringbuf_reserve),            \
5014        FN(ringbuf_submit),             \
5015        FN(ringbuf_discard),            \
5016        FN(ringbuf_query),              \
5017        FN(csum_level),                 \
5018        FN(skc_to_tcp6_sock),           \
5019        FN(skc_to_tcp_sock),            \
5020        FN(skc_to_tcp_timewait_sock),   \
5021        FN(skc_to_tcp_request_sock),    \
5022        FN(skc_to_udp6_sock),           \
5023        FN(get_task_stack),             \
5024        FN(load_hdr_opt),               \
5025        FN(store_hdr_opt),              \
5026        FN(reserve_hdr_opt),            \
5027        FN(inode_storage_get),          \
5028        FN(inode_storage_delete),       \
5029        FN(d_path),                     \
5030        FN(copy_from_user),             \
5031        FN(snprintf_btf),               \
5032        FN(seq_printf_btf),             \
5033        FN(skb_cgroup_classid),         \
5034        FN(redirect_neigh),             \
5035        FN(per_cpu_ptr),                \
5036        FN(this_cpu_ptr),               \
5037        FN(redirect_peer),              \
5038        FN(task_storage_get),           \
5039        FN(task_storage_delete),        \
5040        FN(get_current_task_btf),       \
5041        FN(bprm_opts_set),              \
5042        FN(ktime_get_coarse_ns),        \
5043        FN(ima_inode_hash),             \
5044        FN(sock_from_file),             \
5045        FN(check_mtu),                  \
5046        FN(for_each_map_elem),          \
5047        FN(snprintf),                   \
5048        FN(sys_bpf),                    \
5049        FN(btf_find_by_name_kind),      \
5050        FN(sys_close),                  \
5051        FN(timer_init),                 \
5052        FN(timer_set_callback),         \
5053        FN(timer_start),                \
5054        FN(timer_cancel),               \
5055        FN(get_func_ip),                \
5056        FN(get_attach_cookie),          \
5057        FN(task_pt_regs),               \
5058        /* */
5059
5060/* integer value in 'imm' field of BPF_CALL instruction selects which helper
5061 * function eBPF program intends to call
5062 */
5063#define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
5064enum bpf_func_id {
5065        __BPF_FUNC_MAPPER(__BPF_ENUM_FN)
5066        __BPF_FUNC_MAX_ID,
5067};
5068#undef __BPF_ENUM_FN
5069
5070/* All flags used by eBPF helper functions, placed here. */
5071
5072/* BPF_FUNC_skb_store_bytes flags. */
5073enum {
5074        BPF_F_RECOMPUTE_CSUM            = (1ULL << 0),
5075        BPF_F_INVALIDATE_HASH           = (1ULL << 1),
5076};
5077
5078/* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
5079 * First 4 bits are for passing the header field size.
5080 */
5081enum {
5082        BPF_F_HDR_FIELD_MASK            = 0xfULL,
5083};
5084
5085/* BPF_FUNC_l4_csum_replace flags. */
5086enum {
5087        BPF_F_PSEUDO_HDR                = (1ULL << 4),
5088        BPF_F_MARK_MANGLED_0            = (1ULL << 5),
5089        BPF_F_MARK_ENFORCE              = (1ULL << 6),
5090};
5091
5092/* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
5093enum {
5094        BPF_F_INGRESS                   = (1ULL << 0),
5095};
5096
5097/* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
5098enum {
5099        BPF_F_TUNINFO_IPV6              = (1ULL << 0),
5100};
5101
5102/* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
5103enum {
5104        BPF_F_SKIP_FIELD_MASK           = 0xffULL,
5105        BPF_F_USER_STACK                = (1ULL << 8),
5106/* flags used by BPF_FUNC_get_stackid only. */
5107        BPF_F_FAST_STACK_CMP            = (1ULL << 9),
5108        BPF_F_REUSE_STACKID             = (1ULL << 10),
5109/* flags used by BPF_FUNC_get_stack only. */
5110        BPF_F_USER_BUILD_ID             = (1ULL << 11),
5111};
5112
5113/* BPF_FUNC_skb_set_tunnel_key flags. */
5114enum {
5115        BPF_F_ZERO_CSUM_TX              = (1ULL << 1),
5116        BPF_F_DONT_FRAGMENT             = (1ULL << 2),
5117        BPF_F_SEQ_NUMBER                = (1ULL << 3),
5118};
5119
5120/* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
5121 * BPF_FUNC_perf_event_read_value flags.
5122 */
5123enum {
5124        BPF_F_INDEX_MASK                = 0xffffffffULL,
5125        BPF_F_CURRENT_CPU               = BPF_F_INDEX_MASK,
5126/* BPF_FUNC_perf_event_output for sk_buff input context. */
5127        BPF_F_CTXLEN_MASK               = (0xfffffULL << 32),
5128};
5129
5130/* Current network namespace */
5131enum {
5132        BPF_F_CURRENT_NETNS             = (-1L),
5133};
5134
5135/* BPF_FUNC_csum_level level values. */
5136enum {
5137        BPF_CSUM_LEVEL_QUERY,
5138        BPF_CSUM_LEVEL_INC,
5139        BPF_CSUM_LEVEL_DEC,
5140        BPF_CSUM_LEVEL_RESET,
5141};
5142
5143/* BPF_FUNC_skb_adjust_room flags. */
5144enum {
5145        BPF_F_ADJ_ROOM_FIXED_GSO        = (1ULL << 0),
5146        BPF_F_ADJ_ROOM_ENCAP_L3_IPV4    = (1ULL << 1),
5147        BPF_F_ADJ_ROOM_ENCAP_L3_IPV6    = (1ULL << 2),
5148        BPF_F_ADJ_ROOM_ENCAP_L4_GRE     = (1ULL << 3),
5149        BPF_F_ADJ_ROOM_ENCAP_L4_UDP     = (1ULL << 4),
5150        BPF_F_ADJ_ROOM_NO_CSUM_RESET    = (1ULL << 5),
5151        BPF_F_ADJ_ROOM_ENCAP_L2_ETH     = (1ULL << 6),
5152};
5153
5154enum {
5155        BPF_ADJ_ROOM_ENCAP_L2_MASK      = 0xff,
5156        BPF_ADJ_ROOM_ENCAP_L2_SHIFT     = 56,
5157};
5158
5159#define BPF_F_ADJ_ROOM_ENCAP_L2(len)    (((__u64)len & \
5160                                          BPF_ADJ_ROOM_ENCAP_L2_MASK) \
5161                                         << BPF_ADJ_ROOM_ENCAP_L2_SHIFT)
5162
5163/* BPF_FUNC_sysctl_get_name flags. */
5164enum {
5165        BPF_F_SYSCTL_BASE_NAME          = (1ULL << 0),
5166};
5167
5168/* BPF_FUNC_<kernel_obj>_storage_get flags */
5169enum {
5170        BPF_LOCAL_STORAGE_GET_F_CREATE  = (1ULL << 0),
5171        /* BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility
5172         * and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead.
5173         */
5174        BPF_SK_STORAGE_GET_F_CREATE  = BPF_LOCAL_STORAGE_GET_F_CREATE,
5175};
5176
5177/* BPF_FUNC_read_branch_records flags. */
5178enum {
5179        BPF_F_GET_BRANCH_RECORDS_SIZE   = (1ULL << 0),
5180};
5181
5182/* BPF_FUNC_bpf_ringbuf_commit, BPF_FUNC_bpf_ringbuf_discard, and
5183 * BPF_FUNC_bpf_ringbuf_output flags.
5184 */
5185enum {
5186        BPF_RB_NO_WAKEUP                = (1ULL << 0),
5187        BPF_RB_FORCE_WAKEUP             = (1ULL << 1),
5188};
5189
5190/* BPF_FUNC_bpf_ringbuf_query flags */
5191enum {
5192        BPF_RB_AVAIL_DATA = 0,
5193        BPF_RB_RING_SIZE = 1,
5194        BPF_RB_CONS_POS = 2,
5195        BPF_RB_PROD_POS = 3,
5196};
5197
5198/* BPF ring buffer constants */
5199enum {
5200        BPF_RINGBUF_BUSY_BIT            = (1U << 31),
5201        BPF_RINGBUF_DISCARD_BIT         = (1U << 30),
5202        BPF_RINGBUF_HDR_SZ              = 8,
5203};
5204
5205/* BPF_FUNC_sk_assign flags in bpf_sk_lookup context. */
5206enum {
5207        BPF_SK_LOOKUP_F_REPLACE         = (1ULL << 0),
5208        BPF_SK_LOOKUP_F_NO_REUSEPORT    = (1ULL << 1),
5209};
5210
5211/* Mode for BPF_FUNC_skb_adjust_room helper. */
5212enum bpf_adj_room_mode {
5213        BPF_ADJ_ROOM_NET,
5214        BPF_ADJ_ROOM_MAC,
5215};
5216
5217/* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
5218enum bpf_hdr_start_off {
5219        BPF_HDR_START_MAC,
5220        BPF_HDR_START_NET,
5221};
5222
5223/* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
5224enum bpf_lwt_encap_mode {
5225        BPF_LWT_ENCAP_SEG6,
5226        BPF_LWT_ENCAP_SEG6_INLINE,
5227        BPF_LWT_ENCAP_IP,
5228};
5229
5230/* Flags for bpf_bprm_opts_set helper */
5231enum {
5232        BPF_F_BPRM_SECUREEXEC   = (1ULL << 0),
5233};
5234
5235/* Flags for bpf_redirect_map helper */
5236enum {
5237        BPF_F_BROADCAST         = (1ULL << 3),
5238        BPF_F_EXCLUDE_INGRESS   = (1ULL << 4),
5239};
5240
5241#define __bpf_md_ptr(type, name)        \
5242union {                                 \
5243        type name;                      \
5244        __u64 :64;                      \
5245} __attribute__((aligned(8)))
5246
5247/* user accessible mirror of in-kernel sk_buff.
5248 * new fields can only be added to the end of this structure
5249 */
5250struct __sk_buff {
5251        __u32 len;
5252        __u32 pkt_type;
5253        __u32 mark;
5254        __u32 queue_mapping;
5255        __u32 protocol;
5256        __u32 vlan_present;
5257        __u32 vlan_tci;
5258        __u32 vlan_proto;
5259        __u32 priority;
5260        __u32 ingress_ifindex;
5261        __u32 ifindex;
5262        __u32 tc_index;
5263        __u32 cb[5];
5264        __u32 hash;
5265        __u32 tc_classid;
5266        __u32 data;
5267        __u32 data_end;
5268        __u32 napi_id;
5269
5270        /* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
5271        __u32 family;
5272        __u32 remote_ip4;       /* Stored in network byte order */
5273        __u32 local_ip4;        /* Stored in network byte order */
5274        __u32 remote_ip6[4];    /* Stored in network byte order */
5275        __u32 local_ip6[4];     /* Stored in network byte order */
5276        __u32 remote_port;      /* Stored in network byte order */
5277        __u32 local_port;       /* stored in host byte order */
5278        /* ... here. */
5279
5280        __u32 data_meta;
5281        __bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
5282        __u64 tstamp;
5283        __u32 wire_len;
5284        __u32 gso_segs;
5285        __bpf_md_ptr(struct bpf_sock *, sk);
5286        __u32 gso_size;
5287};
5288
5289struct bpf_tunnel_key {
5290        __u32 tunnel_id;
5291        union {
5292                __u32 remote_ipv4;
5293                __u32 remote_ipv6[4];
5294        };
5295        __u8 tunnel_tos;
5296        __u8 tunnel_ttl;
5297        __u16 tunnel_ext;       /* Padding, future use. */
5298        __u32 tunnel_label;
5299};
5300
5301/* user accessible mirror of in-kernel xfrm_state.
5302 * new fields can only be added to the end of this structure
5303 */
5304struct bpf_xfrm_state {
5305        __u32 reqid;
5306        __u32 spi;      /* Stored in network byte order */
5307        __u16 family;
5308        __u16 ext;      /* Padding, future use. */
5309        union {
5310                __u32 remote_ipv4;      /* Stored in network byte order */
5311                __u32 remote_ipv6[4];   /* Stored in network byte order */
5312        };
5313};
5314
5315/* Generic BPF return codes which all BPF program types may support.
5316 * The values are binary compatible with their TC_ACT_* counter-part to
5317 * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
5318 * programs.
5319 *
5320 * XDP is handled seprately, see XDP_*.
5321 */
5322enum bpf_ret_code {
5323        BPF_OK = 0,
5324        /* 1 reserved */
5325        BPF_DROP = 2,
5326        /* 3-6 reserved */
5327        BPF_REDIRECT = 7,
5328        /* >127 are reserved for prog type specific return codes.
5329         *
5330         * BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and
5331         *    BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been
5332         *    changed and should be routed based on its new L3 header.
5333         *    (This is an L3 redirect, as opposed to L2 redirect
5334         *    represented by BPF_REDIRECT above).
5335         */
5336        BPF_LWT_REROUTE = 128,
5337};
5338
5339struct bpf_sock {
5340        __u32 bound_dev_if;
5341        __u32 family;
5342        __u32 type;
5343        __u32 protocol;
5344        __u32 mark;
5345        __u32 priority;
5346        /* IP address also allows 1 and 2 bytes access */
5347        __u32 src_ip4;
5348        __u32 src_ip6[4];
5349        __u32 src_port;         /* host byte order */
5350        __u32 dst_port;         /* network byte order */
5351        __u32 dst_ip4;
5352        __u32 dst_ip6[4];
5353        __u32 state;
5354        __s32 rx_queue_mapping;
5355};
5356
5357struct bpf_tcp_sock {
5358        __u32 snd_cwnd;         /* Sending congestion window            */
5359        __u32 srtt_us;          /* smoothed round trip time << 3 in usecs */
5360        __u32 rtt_min;
5361        __u32 snd_ssthresh;     /* Slow start size threshold            */
5362        __u32 rcv_nxt;          /* What we want to receive next         */
5363        __u32 snd_nxt;          /* Next sequence we send                */
5364        __u32 snd_una;          /* First byte we want an ack for        */
5365        __u32 mss_cache;        /* Cached effective mss, not including SACKS */
5366        __u32 ecn_flags;        /* ECN status bits.                     */
5367        __u32 rate_delivered;   /* saved rate sample: packets delivered */
5368        __u32 rate_interval_us; /* saved rate sample: time elapsed */
5369        __u32 packets_out;      /* Packets which are "in flight"        */
5370        __u32 retrans_out;      /* Retransmitted packets out            */
5371        __u32 total_retrans;    /* Total retransmits for entire connection */
5372        __u32 segs_in;          /* RFC4898 tcpEStatsPerfSegsIn
5373                                 * total number of segments in.
5374                                 */
5375        __u32 data_segs_in;     /* RFC4898 tcpEStatsPerfDataSegsIn
5376                                 * total number of data segments in.
5377                                 */
5378        __u32 segs_out;         /* RFC4898 tcpEStatsPerfSegsOut
5379                                 * The total number of segments sent.
5380                                 */
5381        __u32 data_segs_out;    /* RFC4898 tcpEStatsPerfDataSegsOut
5382                                 * total number of data segments sent.
5383                                 */
5384        __u32 lost_out;         /* Lost packets                 */
5385        __u32 sacked_out;       /* SACK'd packets                       */
5386        __u64 bytes_received;   /* RFC4898 tcpEStatsAppHCThruOctetsReceived
5387                                 * sum(delta(rcv_nxt)), or how many bytes
5388                                 * were acked.
5389                                 */
5390        __u64 bytes_acked;      /* RFC4898 tcpEStatsAppHCThruOctetsAcked
5391                                 * sum(delta(snd_una)), or how many bytes
5392                                 * were acked.
5393                                 */
5394        __u32 dsack_dups;       /* RFC4898 tcpEStatsStackDSACKDups
5395                                 * total number of DSACK blocks received
5396                                 */
5397        __u32 delivered;        /* Total data packets delivered incl. rexmits */
5398        __u32 delivered_ce;     /* Like the above but only ECE marked packets */
5399        __u32 icsk_retransmits; /* Number of unrecovered [RTO] timeouts */
5400};
5401
5402struct bpf_sock_tuple {
5403        union {
5404                struct {
5405                        __be32 saddr;
5406                        __be32 daddr;
5407                        __be16 sport;
5408                        __be16 dport;
5409                } ipv4;
5410                struct {
5411                        __be32 saddr[4];
5412                        __be32 daddr[4];
5413                        __be16 sport;
5414                        __be16 dport;
5415                } ipv6;
5416        };
5417};
5418
5419struct bpf_xdp_sock {
5420        __u32 queue_id;
5421};
5422
5423#define XDP_PACKET_HEADROOM 256
5424
5425/* User return codes for XDP prog type.
5426 * A valid XDP program must return one of these defined values. All other
5427 * return codes are reserved for future use. Unknown return codes will
5428 * result in packet drops and a warning via bpf_warn_invalid_xdp_action().
5429 */
5430enum xdp_action {
5431        XDP_ABORTED = 0,
5432        XDP_DROP,
5433        XDP_PASS,
5434        XDP_TX,
5435        XDP_REDIRECT,
5436};
5437
5438/* user accessible metadata for XDP packet hook
5439 * new fields must be added to the end of this structure
5440 */
5441struct xdp_md {
5442        __u32 data;
5443        __u32 data_end;
5444        __u32 data_meta;
5445        /* Below access go through struct xdp_rxq_info */
5446        __u32 ingress_ifindex; /* rxq->dev->ifindex */
5447        __u32 rx_queue_index;  /* rxq->queue_index  */
5448
5449        __u32 egress_ifindex;  /* txq->dev->ifindex */
5450};
5451
5452/* DEVMAP map-value layout
5453 *
5454 * The struct data-layout of map-value is a configuration interface.
5455 * New members can only be added to the end of this structure.
5456 */
5457struct bpf_devmap_val {
5458        __u32 ifindex;   /* device index */
5459        union {
5460                int   fd;  /* prog fd on map write */
5461                __u32 id;  /* prog id on map read */
5462        } bpf_prog;
5463};
5464
5465/* CPUMAP map-value layout
5466 *
5467 * The struct data-layout of map-value is a configuration interface.
5468 * New members can only be added to the end of this structure.
5469 */
5470struct bpf_cpumap_val {
5471        __u32 qsize;    /* queue size to remote target CPU */
5472        union {
5473                int   fd;       /* prog fd on map write */
5474                __u32 id;       /* prog id on map read */
5475        } bpf_prog;
5476};
5477
5478enum sk_action {
5479        SK_DROP = 0,
5480        SK_PASS,
5481};
5482
5483/* user accessible metadata for SK_MSG packet hook, new fields must
5484 * be added to the end of this structure
5485 */
5486struct sk_msg_md {
5487        __bpf_md_ptr(void *, data);
5488        __bpf_md_ptr(void *, data_end);
5489
5490        __u32 family;
5491        __u32 remote_ip4;       /* Stored in network byte order */
5492        __u32 local_ip4;        /* Stored in network byte order */
5493        __u32 remote_ip6[4];    /* Stored in network byte order */
5494        __u32 local_ip6[4];     /* Stored in network byte order */
5495        __u32 remote_port;      /* Stored in network byte order */
5496        __u32 local_port;       /* stored in host byte order */
5497        __u32 size;             /* Total size of sk_msg */
5498
5499        __bpf_md_ptr(struct bpf_sock *, sk); /* current socket */
5500};
5501
5502struct sk_reuseport_md {
5503        /*
5504         * Start of directly accessible data. It begins from
5505         * the tcp/udp header.
5506         */
5507        __bpf_md_ptr(void *, data);
5508        /* End of directly accessible data */
5509        __bpf_md_ptr(void *, data_end);
5510        /*
5511         * Total length of packet (starting from the tcp/udp header).
5512         * Note that the directly accessible bytes (data_end - data)
5513         * could be less than this "len".  Those bytes could be
5514         * indirectly read by a helper "bpf_skb_load_bytes()".
5515         */
5516        __u32 len;
5517        /*
5518         * Eth protocol in the mac header (network byte order). e.g.
5519         * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
5520         */
5521        __u32 eth_protocol;
5522        __u32 ip_protocol;      /* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
5523        __u32 bind_inany;       /* Is sock bound to an INANY address? */
5524        __u32 hash;             /* A hash of the packet 4 tuples */
5525        /* When reuse->migrating_sk is NULL, it is selecting a sk for the
5526         * new incoming connection request (e.g. selecting a listen sk for
5527         * the received SYN in the TCP case).  reuse->sk is one of the sk
5528         * in the reuseport group. The bpf prog can use reuse->sk to learn
5529         * the local listening ip/port without looking into the skb.
5530         *
5531         * When reuse->migrating_sk is not NULL, reuse->sk is closed and
5532         * reuse->migrating_sk is the socket that needs to be migrated
5533         * to another listening socket.  migrating_sk could be a fullsock
5534         * sk that is fully established or a reqsk that is in-the-middle
5535         * of 3-way handshake.
5536         */
5537        __bpf_md_ptr(struct bpf_sock *, sk);
5538        __bpf_md_ptr(struct bpf_sock *, migrating_sk);
5539};
5540
5541#define BPF_TAG_SIZE    8
5542
5543struct bpf_prog_info {
5544        __u32 type;
5545        __u32 id;
5546        __u8  tag[BPF_TAG_SIZE];
5547        __u32 jited_prog_len;
5548        __u32 xlated_prog_len;
5549        __aligned_u64 jited_prog_insns;
5550        __aligned_u64 xlated_prog_insns;
5551        __u64 load_time;        /* ns since boottime */
5552        __u32 created_by_uid;
5553        __u32 nr_map_ids;
5554        __aligned_u64 map_ids;
5555        char name[BPF_OBJ_NAME_LEN];
5556        __u32 ifindex;
5557        __u32 gpl_compatible:1;
5558        __u32 :31; /* alignment pad */
5559        __u64 netns_dev;
5560        __u64 netns_ino;
5561        __u32 nr_jited_ksyms;
5562        __u32 nr_jited_func_lens;
5563        __aligned_u64 jited_ksyms;
5564        __aligned_u64 jited_func_lens;
5565        __u32 btf_id;
5566        __u32 func_info_rec_size;
5567        __aligned_u64 func_info;
5568        __u32 nr_func_info;
5569        __u32 nr_line_info;
5570        __aligned_u64 line_info;
5571        __aligned_u64 jited_line_info;
5572        __u32 nr_jited_line_info;
5573        __u32 line_info_rec_size;
5574        __u32 jited_line_info_rec_size;
5575        __u32 nr_prog_tags;
5576        __aligned_u64 prog_tags;
5577        __u64 run_time_ns;
5578        __u64 run_cnt;
5579        __u64 recursion_misses;
5580} __attribute__((aligned(8)));
5581
5582struct bpf_map_info {
5583        __u32 type;
5584        __u32 id;
5585        __u32 key_size;
5586        __u32 value_size;
5587        __u32 max_entries;
5588        __u32 map_flags;
5589        char  name[BPF_OBJ_NAME_LEN];
5590        __u32 ifindex;
5591        __u32 btf_vmlinux_value_type_id;
5592        __u64 netns_dev;
5593        __u64 netns_ino;
5594        __u32 btf_id;
5595        __u32 btf_key_type_id;
5596        __u32 btf_value_type_id;
5597} __attribute__((aligned(8)));
5598
5599struct bpf_btf_info {
5600        __aligned_u64 btf;
5601        __u32 btf_size;
5602        __u32 id;
5603        __aligned_u64 name;
5604        __u32 name_len;
5605        __u32 kernel_btf;
5606} __attribute__((aligned(8)));
5607
5608struct bpf_link_info {
5609        __u32 type;
5610        __u32 id;
5611        __u32 prog_id;
5612        union {
5613                struct {
5614                        __aligned_u64 tp_name; /* in/out: tp_name buffer ptr */
5615                        __u32 tp_name_len;     /* in/out: tp_name buffer len */
5616                } raw_tracepoint;
5617                struct {
5618                        __u32 attach_type;
5619                        __u32 target_obj_id; /* prog_id for PROG_EXT, otherwise btf object id */
5620                        __u32 target_btf_id; /* BTF type id inside the object */
5621                } tracing;
5622                struct {
5623                        __u64 cgroup_id;
5624                        __u32 attach_type;
5625                } cgroup;
5626                struct {
5627                        __aligned_u64 target_name; /* in/out: target_name buffer ptr */
5628                        __u32 target_name_len;     /* in/out: target_name buffer len */
5629                        union {
5630                                struct {
5631                                        __u32 map_id;
5632                                } map;
5633                        };
5634                } iter;
5635                struct  {
5636                        __u32 netns_ino;
5637                        __u32 attach_type;
5638                } netns;
5639                struct {
5640                        __u32 ifindex;
5641                } xdp;
5642        };
5643} __attribute__((aligned(8)));
5644
5645/* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
5646 * by user and intended to be used by socket (e.g. to bind to, depends on
5647 * attach type).
5648 */
5649struct bpf_sock_addr {
5650        __u32 user_family;      /* Allows 4-byte read, but no write. */
5651        __u32 user_ip4;         /* Allows 1,2,4-byte read and 4-byte write.
5652                                 * Stored in network byte order.
5653                                 */
5654        __u32 user_ip6[4];      /* Allows 1,2,4,8-byte read and 4,8-byte write.
5655                                 * Stored in network byte order.
5656                                 */
5657        __u32 user_port;        /* Allows 1,2,4-byte read and 4-byte write.
5658                                 * Stored in network byte order
5659                                 */
5660        __u32 family;           /* Allows 4-byte read, but no write */
5661        __u32 type;             /* Allows 4-byte read, but no write */
5662        __u32 protocol;         /* Allows 4-byte read, but no write */
5663        __u32 msg_src_ip4;      /* Allows 1,2,4-byte read and 4-byte write.
5664                                 * Stored in network byte order.
5665                                 */
5666        __u32 msg_src_ip6[4];   /* Allows 1,2,4,8-byte read and 4,8-byte write.
5667                                 * Stored in network byte order.
5668                                 */
5669        __bpf_md_ptr(struct bpf_sock *, sk);
5670};
5671
5672/* User bpf_sock_ops struct to access socket values and specify request ops
5673 * and their replies.
5674 * Some of this fields are in network (bigendian) byte order and may need
5675 * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
5676 * New fields can only be added at the end of this structure
5677 */
5678struct bpf_sock_ops {
5679        __u32 op;
5680        union {
5681                __u32 args[4];          /* Optionally passed to bpf program */
5682                __u32 reply;            /* Returned by bpf program          */
5683                __u32 replylong[4];     /* Optionally returned by bpf prog  */
5684        };
5685        __u32 family;
5686        __u32 remote_ip4;       /* Stored in network byte order */
5687        __u32 local_ip4;        /* Stored in network byte order */
5688        __u32 remote_ip6[4];    /* Stored in network byte order */
5689        __u32 local_ip6[4];     /* Stored in network byte order */
5690        __u32 remote_port;      /* Stored in network byte order */
5691        __u32 local_port;       /* stored in host byte order */
5692        __u32 is_fullsock;      /* Some TCP fields are only valid if
5693                                 * there is a full socket. If not, the
5694                                 * fields read as zero.
5695                                 */
5696        __u32 snd_cwnd;
5697        __u32 srtt_us;          /* Averaged RTT << 3 in usecs */
5698        __u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
5699        __u32 state;
5700        __u32 rtt_min;
5701        __u32 snd_ssthresh;
5702        __u32 rcv_nxt;
5703        __u32 snd_nxt;
5704        __u32 snd_una;
5705        __u32 mss_cache;
5706        __u32 ecn_flags;
5707        __u32 rate_delivered;
5708        __u32 rate_interval_us;
5709        __u32 packets_out;
5710        __u32 retrans_out;
5711        __u32 total_retrans;
5712        __u32 segs_in;
5713        __u32 data_segs_in;
5714        __u32 segs_out;
5715        __u32 data_segs_out;
5716        __u32 lost_out;
5717        __u32 sacked_out;
5718        __u32 sk_txhash;
5719        __u64 bytes_received;
5720        __u64 bytes_acked;
5721        __bpf_md_ptr(struct bpf_sock *, sk);
5722        /* [skb_data, skb_data_end) covers the whole TCP header.
5723         *
5724         * BPF_SOCK_OPS_PARSE_HDR_OPT_CB: The packet received
5725         * BPF_SOCK_OPS_HDR_OPT_LEN_CB:   Not useful because the
5726         *                                header has not been written.
5727         * BPF_SOCK_OPS_WRITE_HDR_OPT_CB: The header and options have
5728         *                                been written so far.
5729         * BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:  The SYNACK that concludes
5730         *                                      the 3WHS.
5731         * BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: The ACK that concludes
5732         *                                      the 3WHS.
5733         *
5734         * bpf_load_hdr_opt() can also be used to read a particular option.
5735         */
5736        __bpf_md_ptr(void *, skb_data);
5737        __bpf_md_ptr(void *, skb_data_end);
5738        __u32 skb_len;          /* The total length of a packet.
5739                                 * It includes the header, options,
5740                                 * and payload.
5741                                 */
5742        __u32 skb_tcp_flags;    /* tcp_flags of the header.  It provides
5743                                 * an easy way to check for tcp_flags
5744                                 * without parsing skb_data.
5745                                 *
5746                                 * In particular, the skb_tcp_flags
5747                                 * will still be available in
5748                                 * BPF_SOCK_OPS_HDR_OPT_LEN even though
5749                                 * the outgoing header has not
5750                                 * been written yet.
5751                                 */
5752};
5753
5754/* Definitions for bpf_sock_ops_cb_flags */
5755enum {
5756        BPF_SOCK_OPS_RTO_CB_FLAG        = (1<<0),
5757        BPF_SOCK_OPS_RETRANS_CB_FLAG    = (1<<1),
5758        BPF_SOCK_OPS_STATE_CB_FLAG      = (1<<2),
5759        BPF_SOCK_OPS_RTT_CB_FLAG        = (1<<3),
5760        /* Call bpf for all received TCP headers.  The bpf prog will be
5761         * called under sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5762         *
5763         * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5764         * for the header option related helpers that will be useful
5765         * to the bpf programs.
5766         *
5767         * It could be used at the client/active side (i.e. connect() side)
5768         * when the server told it that the server was in syncookie
5769         * mode and required the active side to resend the bpf-written
5770         * options.  The active side can keep writing the bpf-options until
5771         * it received a valid packet from the server side to confirm
5772         * the earlier packet (and options) has been received.  The later
5773         * example patch is using it like this at the active side when the
5774         * server is in syncookie mode.
5775         *
5776         * The bpf prog will usually turn this off in the common cases.
5777         */
5778        BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG  = (1<<4),
5779        /* Call bpf when kernel has received a header option that
5780         * the kernel cannot handle.  The bpf prog will be called under
5781         * sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB.
5782         *
5783         * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5784         * for the header option related helpers that will be useful
5785         * to the bpf programs.
5786         */
5787        BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG = (1<<5),
5788        /* Call bpf when the kernel is writing header options for the
5789         * outgoing packet.  The bpf prog will first be called
5790         * to reserve space in a skb under
5791         * sock_ops->op == BPF_SOCK_OPS_HDR_OPT_LEN_CB.  Then
5792         * the bpf prog will be called to write the header option(s)
5793         * under sock_ops->op == BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
5794         *
5795         * Please refer to the comment in BPF_SOCK_OPS_HDR_OPT_LEN_CB
5796         * and BPF_SOCK_OPS_WRITE_HDR_OPT_CB for the header option
5797         * related helpers that will be useful to the bpf programs.
5798         *
5799         * The kernel gets its chance to reserve space and write
5800         * options first before the BPF program does.
5801         */
5802        BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (1<<6),
5803/* Mask of all currently supported cb flags */
5804        BPF_SOCK_OPS_ALL_CB_FLAGS       = 0x7F,
5805};
5806
5807/* List of known BPF sock_ops operators.
5808 * New entries can only be added at the end
5809 */
5810enum {
5811        BPF_SOCK_OPS_VOID,
5812        BPF_SOCK_OPS_TIMEOUT_INIT,      /* Should return SYN-RTO value to use or
5813                                         * -1 if default value should be used
5814                                         */
5815        BPF_SOCK_OPS_RWND_INIT,         /* Should return initial advertized
5816                                         * window (in packets) or -1 if default
5817                                         * value should be used
5818                                         */
5819        BPF_SOCK_OPS_TCP_CONNECT_CB,    /* Calls BPF program right before an
5820                                         * active connection is initialized
5821                                         */
5822        BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB,     /* Calls BPF program when an
5823                                                 * active connection is
5824                                                 * established
5825                                                 */
5826        BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB,    /* Calls BPF program when a
5827                                                 * passive connection is
5828                                                 * established
5829                                                 */
5830        BPF_SOCK_OPS_NEEDS_ECN,         /* If connection's congestion control
5831                                         * needs ECN
5832                                         */
5833        BPF_SOCK_OPS_BASE_RTT,          /* Get base RTT. The correct value is
5834                                         * based on the path and may be
5835                                         * dependent on the congestion control
5836                                         * algorithm. In general it indicates
5837                                         * a congestion threshold. RTTs above
5838                                         * this indicate congestion
5839                                         */
5840        BPF_SOCK_OPS_RTO_CB,            /* Called when an RTO has triggered.
5841                                         * Arg1: value of icsk_retransmits
5842                                         * Arg2: value of icsk_rto
5843                                         * Arg3: whether RTO has expired
5844                                         */
5845        BPF_SOCK_OPS_RETRANS_CB,        /* Called when skb is retransmitted.
5846                                         * Arg1: sequence number of 1st byte
5847                                         * Arg2: # segments
5848                                         * Arg3: return value of
5849                                         *       tcp_transmit_skb (0 => success)
5850                                         */
5851        BPF_SOCK_OPS_STATE_CB,          /* Called when TCP changes state.
5852                                         * Arg1: old_state
5853                                         * Arg2: new_state
5854                                         */
5855        BPF_SOCK_OPS_TCP_LISTEN_CB,     /* Called on listen(2), right after
5856                                         * socket transition to LISTEN state.
5857                                         */
5858        BPF_SOCK_OPS_RTT_CB,            /* Called on every RTT.
5859                                         */
5860        BPF_SOCK_OPS_PARSE_HDR_OPT_CB,  /* Parse the header option.
5861                                         * It will be called to handle
5862                                         * the packets received at
5863                                         * an already established
5864                                         * connection.
5865                                         *
5866                                         * sock_ops->skb_data:
5867                                         * Referring to the received skb.
5868                                         * It covers the TCP header only.
5869                                         *
5870                                         * bpf_load_hdr_opt() can also
5871                                         * be used to search for a
5872                                         * particular option.
5873                                         */
5874        BPF_SOCK_OPS_HDR_OPT_LEN_CB,    /* Reserve space for writing the
5875                                         * header option later in
5876                                         * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
5877                                         * Arg1: bool want_cookie. (in
5878                                         *       writing SYNACK only)
5879                                         *
5880                                         * sock_ops->skb_data:
5881                                         * Not available because no header has
5882                                         * been written yet.
5883                                         *
5884                                         * sock_ops->skb_tcp_flags:
5885                                         * The tcp_flags of the
5886                                         * outgoing skb. (e.g. SYN, ACK, FIN).
5887                                         *
5888                                         * bpf_reserve_hdr_opt() should
5889                                         * be used to reserve space.
5890                                         */
5891        BPF_SOCK_OPS_WRITE_HDR_OPT_CB,  /* Write the header options
5892                                         * Arg1: bool want_cookie. (in
5893                                         *       writing SYNACK only)
5894                                         *
5895                                         * sock_ops->skb_data:
5896                                         * Referring to the outgoing skb.
5897                                         * It covers the TCP header
5898                                         * that has already been written
5899                                         * by the kernel and the
5900                                         * earlier bpf-progs.
5901                                         *
5902                                         * sock_ops->skb_tcp_flags:
5903                                         * The tcp_flags of the outgoing
5904                                         * skb. (e.g. SYN, ACK, FIN).
5905                                         *
5906                                         * bpf_store_hdr_opt() should
5907                                         * be used to write the
5908                                         * option.
5909                                         *
5910                                         * bpf_load_hdr_opt() can also
5911                                         * be used to search for a
5912                                         * particular option that
5913                                         * has already been written
5914                                         * by the kernel or the
5915                                         * earlier bpf-progs.
5916                                         */
5917};
5918
5919/* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
5920 * changes between the TCP and BPF versions. Ideally this should never happen.
5921 * If it does, we need to add code to convert them before calling
5922 * the BPF sock_ops function.
5923 */
5924enum {
5925        BPF_TCP_ESTABLISHED = 1,
5926        BPF_TCP_SYN_SENT,
5927        BPF_TCP_SYN_RECV,
5928        BPF_TCP_FIN_WAIT1,
5929        BPF_TCP_FIN_WAIT2,
5930        BPF_TCP_TIME_WAIT,
5931        BPF_TCP_CLOSE,
5932        BPF_TCP_CLOSE_WAIT,
5933        BPF_TCP_LAST_ACK,
5934        BPF_TCP_LISTEN,
5935        BPF_TCP_CLOSING,        /* Now a valid state */
5936        BPF_TCP_NEW_SYN_RECV,
5937
5938        BPF_TCP_MAX_STATES      /* Leave at the end! */
5939};
5940
5941enum {
5942        TCP_BPF_IW              = 1001, /* Set TCP initial congestion window */
5943        TCP_BPF_SNDCWND_CLAMP   = 1002, /* Set sndcwnd_clamp */
5944        TCP_BPF_DELACK_MAX      = 1003, /* Max delay ack in usecs */
5945        TCP_BPF_RTO_MIN         = 1004, /* Min delay ack in usecs */
5946        /* Copy the SYN pkt to optval
5947         *
5948         * BPF_PROG_TYPE_SOCK_OPS only.  It is similar to the
5949         * bpf_getsockopt(TCP_SAVED_SYN) but it does not limit
5950         * to only getting from the saved_syn.  It can either get the
5951         * syn packet from:
5952         *
5953         * 1. the just-received SYN packet (only available when writing the
5954         *    SYNACK).  It will be useful when it is not necessary to
5955         *    save the SYN packet for latter use.  It is also the only way
5956         *    to get the SYN during syncookie mode because the syn
5957         *    packet cannot be saved during syncookie.
5958         *
5959         * OR
5960         *
5961         * 2. the earlier saved syn which was done by
5962         *    bpf_setsockopt(TCP_SAVE_SYN).
5963         *
5964         * The bpf_getsockopt(TCP_BPF_SYN*) option will hide where the
5965         * SYN packet is obtained.
5966         *
5967         * If the bpf-prog does not need the IP[46] header,  the
5968         * bpf-prog can avoid parsing the IP header by using
5969         * TCP_BPF_SYN.  Otherwise, the bpf-prog can get both
5970         * IP[46] and TCP header by using TCP_BPF_SYN_IP.
5971         *
5972         *      >0: Total number of bytes copied
5973         * -ENOSPC: Not enough space in optval. Only optlen number of
5974         *          bytes is copied.
5975         * -ENOENT: The SYN skb is not available now and the earlier SYN pkt
5976         *          is not saved by setsockopt(TCP_SAVE_SYN).
5977         */
5978        TCP_BPF_SYN             = 1005, /* Copy the TCP header */
5979        TCP_BPF_SYN_IP          = 1006, /* Copy the IP[46] and TCP header */
5980        TCP_BPF_SYN_MAC         = 1007, /* Copy the MAC, IP[46], and TCP header */
5981};
5982
5983enum {
5984        BPF_LOAD_HDR_OPT_TCP_SYN = (1ULL << 0),
5985};
5986
5987/* args[0] value during BPF_SOCK_OPS_HDR_OPT_LEN_CB and
5988 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
5989 */
5990enum {
5991        BPF_WRITE_HDR_TCP_CURRENT_MSS = 1,      /* Kernel is finding the
5992                                                 * total option spaces
5993                                                 * required for an established
5994                                                 * sk in order to calculate the
5995                                                 * MSS.  No skb is actually
5996                                                 * sent.
5997                                                 */
5998        BPF_WRITE_HDR_TCP_SYNACK_COOKIE = 2,    /* Kernel is in syncookie mode
5999                                                 * when sending a SYN.
6000                                                 */
6001};
6002
6003struct bpf_perf_event_value {
6004        __u64 counter;
6005        __u64 enabled;
6006        __u64 running;
6007};
6008
6009enum {
6010        BPF_DEVCG_ACC_MKNOD     = (1ULL << 0),
6011        BPF_DEVCG_ACC_READ      = (1ULL << 1),
6012        BPF_DEVCG_ACC_WRITE     = (1ULL << 2),
6013};
6014
6015enum {
6016        BPF_DEVCG_DEV_BLOCK     = (1ULL << 0),
6017        BPF_DEVCG_DEV_CHAR      = (1ULL << 1),
6018};
6019
6020struct bpf_cgroup_dev_ctx {
6021        /* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
6022        __u32 access_type;
6023        __u32 major;
6024        __u32 minor;
6025};
6026
6027struct bpf_raw_tracepoint_args {
6028        __u64 args[0];
6029};
6030
6031/* DIRECT:  Skip the FIB rules and go to FIB table associated with device
6032 * OUTPUT:  Do lookup from egress perspective; default is ingress
6033 */
6034enum {
6035        BPF_FIB_LOOKUP_DIRECT  = (1U << 0),
6036        BPF_FIB_LOOKUP_OUTPUT  = (1U << 1),
6037};
6038
6039enum {
6040        BPF_FIB_LKUP_RET_SUCCESS,      /* lookup successful */
6041        BPF_FIB_LKUP_RET_BLACKHOLE,    /* dest is blackholed; can be dropped */
6042        BPF_FIB_LKUP_RET_UNREACHABLE,  /* dest is unreachable; can be dropped */
6043        BPF_FIB_LKUP_RET_PROHIBIT,     /* dest not allowed; can be dropped */
6044        BPF_FIB_LKUP_RET_NOT_FWDED,    /* packet is not forwarded */
6045        BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
6046        BPF_FIB_LKUP_RET_UNSUPP_LWT,   /* fwd requires encapsulation */
6047        BPF_FIB_LKUP_RET_NO_NEIGH,     /* no neighbor entry for nh */
6048        BPF_FIB_LKUP_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
6049};
6050
6051struct bpf_fib_lookup {
6052        /* input:  network family for lookup (AF_INET, AF_INET6)
6053         * output: network family of egress nexthop
6054         */
6055        __u8    family;
6056
6057        /* set if lookup is to consider L4 data - e.g., FIB rules */
6058        __u8    l4_protocol;
6059        __be16  sport;
6060        __be16  dport;
6061
6062        union { /* used for MTU check */
6063                /* input to lookup */
6064                __u16   tot_len; /* L3 length from network hdr (iph->tot_len) */
6065
6066                /* output: MTU value */
6067                __u16   mtu_result;
6068        };
6069        /* input: L3 device index for lookup
6070         * output: device index from FIB lookup
6071         */
6072        __u32   ifindex;
6073
6074        union {
6075                /* inputs to lookup */
6076                __u8    tos;            /* AF_INET  */
6077                __be32  flowinfo;       /* AF_INET6, flow_label + priority */
6078
6079                /* output: metric of fib result (IPv4/IPv6 only) */
6080                __u32   rt_metric;
6081        };
6082
6083        union {
6084                __be32          ipv4_src;
6085                __u32           ipv6_src[4];  /* in6_addr; network order */
6086        };
6087
6088        /* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
6089         * network header. output: bpf_fib_lookup sets to gateway address
6090         * if FIB lookup returns gateway route
6091         */
6092        union {
6093                __be32          ipv4_dst;
6094                __u32           ipv6_dst[4];  /* in6_addr; network order */
6095        };
6096
6097        /* output */
6098        __be16  h_vlan_proto;
6099        __be16  h_vlan_TCI;
6100        __u8    smac[6];     /* ETH_ALEN */
6101        __u8    dmac[6];     /* ETH_ALEN */
6102};
6103
6104struct bpf_redir_neigh {
6105        /* network family for lookup (AF_INET, AF_INET6) */
6106        __u32 nh_family;
6107        /* network address of nexthop; skips fib lookup to find gateway */
6108        union {
6109                __be32          ipv4_nh;
6110                __u32           ipv6_nh[4];  /* in6_addr; network order */
6111        };
6112};
6113
6114/* bpf_check_mtu flags*/
6115enum  bpf_check_mtu_flags {
6116        BPF_MTU_CHK_SEGS  = (1U << 0),
6117};
6118
6119enum bpf_check_mtu_ret {
6120        BPF_MTU_CHK_RET_SUCCESS,      /* check and lookup successful */
6121        BPF_MTU_CHK_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
6122        BPF_MTU_CHK_RET_SEGS_TOOBIG,  /* GSO re-segmentation needed to fwd */
6123};
6124
6125enum bpf_task_fd_type {
6126        BPF_FD_TYPE_RAW_TRACEPOINT,     /* tp name */
6127        BPF_FD_TYPE_TRACEPOINT,         /* tp name */
6128        BPF_FD_TYPE_KPROBE,             /* (symbol + offset) or addr */
6129        BPF_FD_TYPE_KRETPROBE,          /* (symbol + offset) or addr */
6130        BPF_FD_TYPE_UPROBE,             /* filename + offset */
6131        BPF_FD_TYPE_URETPROBE,          /* filename + offset */
6132};
6133
6134enum {
6135        BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG             = (1U << 0),
6136        BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL         = (1U << 1),
6137        BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP              = (1U << 2),
6138};
6139
6140struct bpf_flow_keys {
6141        __u16   nhoff;
6142        __u16   thoff;
6143        __u16   addr_proto;                     /* ETH_P_* of valid addrs */
6144        __u8    is_frag;
6145        __u8    is_first_frag;
6146        __u8    is_encap;
6147        __u8    ip_proto;
6148        __be16  n_proto;
6149        __be16  sport;
6150        __be16  dport;
6151        union {
6152                struct {
6153                        __be32  ipv4_src;
6154                        __be32  ipv4_dst;
6155                };