/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Linux Socket Filter Data Structures
 */
#ifndef __LINUX_FILTER_H__
#define __LINUX_FILTER_H__

#include <stdarg.h>

#include <linux/atomic.h>
#include <linux/refcount.h>
#include <linux/compat.h>
#include <linux/skbuff.h>
#include <linux/linkage.h>
#include <linux/printk.h>
#include <linux/workqueue.h>
#include <linux/sched.h>
#include <linux/capability.h>
#include <linux/set_memory.h>
#include <linux/kallsyms.h>
#include <linux/if_vlan.h>
#include <linux/vmalloc.h>
#include <linux/sockptr.h>
#include <crypto/sha.h>

#include <net/sch_generic.h>

#include <asm/byteorder.h>
#include <uapi/linux/filter.h>
#include <uapi/linux/bpf.h>

struct sk_buff;
struct sock;
struct seccomp_data;
struct bpf_prog_aux;
struct xdp_rxq_info;
struct xdp_buff;
struct sock_reuseport;
struct ctl_table;
struct ctl_table_header;

/* ArgX, context and stack frame pointer register positions. Note,
 * Arg1, Arg2, Arg3, etc are used as argument mappings of function
 * calls in BPF_CALL instruction.
 */
#define BPF_REG_ARG1    BPF_REG_1
#define BPF_REG_ARG2    BPF_REG_2
#define BPF_REG_ARG3    BPF_REG_3
#define BPF_REG_ARG4    BPF_REG_4
#define BPF_REG_ARG5    BPF_REG_5
#define BPF_REG_CTX     BPF_REG_6
#define BPF_REG_FP      BPF_REG_10

/* Additional register mappings for converted user programs. */
#define BPF_REG_A       BPF_REG_0
#define BPF_REG_X       BPF_REG_7
#define BPF_REG_TMP     BPF_REG_2       /* scratch reg */
#define BPF_REG_D       BPF_REG_8       /* data, callee-saved */
#define BPF_REG_H       BPF_REG_9       /* hlen, callee-saved */

/* Kernel hidden auxiliary/helper register. */
#define BPF_REG_AX              MAX_BPF_REG
#define MAX_BPF_EXT_REG         (MAX_BPF_REG + 1)
#define MAX_BPF_JIT_REG         MAX_BPF_EXT_REG

/* unused opcode to mark special call to bpf_tail_call() helper */
#define BPF_TAIL_CALL   0xf0

/* unused opcode to mark special load instruction. Same as BPF_ABS */
#define BPF_PROBE_MEM   0x20

/* unused opcode to mark call to interpreter with arguments */
#define BPF_CALL_ARGS   0xe0

/* As per nm, we expose JITed images as text (code) section for
 * kallsyms. That way, tools like perf can find it to match
 * addresses.
 */
#define BPF_SYM_ELF_TYPE        't'

/* BPF program can access up to 512 bytes of stack space. */
#define MAX_BPF_STACK   512

/* Helper macros for filter block array initializers. */

/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */

#define BPF_ALU64_REG(OP, DST, SRC)                             \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,        \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = 0,                                     \
                .imm   = 0 })

#define BPF_ALU32_REG(OP, DST, SRC)                             \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU | BPF_OP(OP) | BPF_X,          \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = 0,                                     \
                .imm   = 0 })

/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */

#define BPF_ALU64_IMM(OP, DST, IMM)                             \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,        \
                .dst_reg = DST,                                 \
                .src_reg = 0,                                   \
                .off   = 0,                                     \
                .imm   = IMM })

#define BPF_ALU32_IMM(OP, DST, IMM)                             \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU | BPF_OP(OP) | BPF_K,          \
                .dst_reg = DST,                                 \
                .src_reg = 0,                                   \
                .off   = 0,                                     \
                .imm   = IMM })

/* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */

#define BPF_ENDIAN(TYPE, DST, LEN)                              \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU | BPF_END | BPF_SRC(TYPE),     \
                .dst_reg = DST,                                 \
                .src_reg = 0,                                   \
                .off   = 0,                                     \
                .imm   = LEN })

/* Short form of mov, dst_reg = src_reg */

#define BPF_MOV64_REG(DST, SRC)                                 \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU64 | BPF_MOV | BPF_X,           \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = 0,                                     \
                .imm   = 0 })

#define BPF_MOV32_REG(DST, SRC)                                 \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU | BPF_MOV | BPF_X,             \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = 0,                                     \
                .imm   = 0 })

/* Short form of mov, dst_reg = imm32 */

#define BPF_MOV64_IMM(DST, IMM)                                 \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU64 | BPF_MOV | BPF_K,           \
                .dst_reg = DST,                                 \
                .src_reg = 0,                                   \
                .off   = 0,                                     \
                .imm   = IMM })

#define BPF_MOV32_IMM(DST, IMM)                                 \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU | BPF_MOV | BPF_K,             \
                .dst_reg = DST,                                 \
                .src_reg = 0,                                   \
                .off   = 0,                                     \
                .imm   = IMM })

/* Special form of mov32, used for doing explicit zero extension on dst. */
#define BPF_ZEXT_REG(DST)                                       \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU | BPF_MOV | BPF_X,             \
                .dst_reg = DST,                                 \
                .src_reg = DST,                                 \
                .off   = 0,                                     \
                .imm   = 1 })

static inline bool insn_is_zext(const struct bpf_insn *insn)
{
        return insn->code == (BPF_ALU | BPF_MOV | BPF_X) && insn->imm == 1;
}

/* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
#define BPF_LD_IMM64(DST, IMM)                                  \
        BPF_LD_IMM64_RAW(DST, 0, IMM)

#define BPF_LD_IMM64_RAW(DST, SRC, IMM)                         \
        ((struct bpf_insn) {                                    \
                .code  = BPF_LD | BPF_DW | BPF_IMM,             \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = 0,                                     \
                .imm   = (__u32) (IMM) }),                      \
        ((struct bpf_insn) {                                    \
                .code  = 0, /* zero is reserved opcode */       \
                .dst_reg = 0,                                   \
                .src_reg = 0,                                   \
                .off   = 0,                                     \
                .imm   = ((__u64) (IMM)) >> 32 })

/* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
#define BPF_LD_MAP_FD(DST, MAP_FD)                              \
        BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)

/* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */

#define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)                      \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),   \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = 0,                                     \
                .imm   = IMM })

#define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)                      \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),     \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = 0,                                     \
                .imm   = IMM })

/* Direct packet access, R0 = *(uint *) (skb->data + imm32) */

#define BPF_LD_ABS(SIZE, IMM)                                   \
        ((struct bpf_insn) {                                    \
                .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,     \
                .dst_reg = 0,                                   \
                .src_reg = 0,                                   \
                .off   = 0,                                     \
                .imm   = IMM })

/* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */

#define BPF_LD_IND(SIZE, SRC, IMM)                              \
        ((struct bpf_insn) {                                    \
                .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,     \
                .dst_reg = 0,                                   \
                .src_reg = SRC,                                 \
                .off   = 0,                                     \
                .imm   = IMM })

/* Memory load, dst_reg = *(uint *) (src_reg + off16) */

#define BPF_LDX_MEM(SIZE, DST, SRC, OFF)                        \
        ((struct bpf_insn) {                                    \
                .code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,    \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = OFF,                                   \
                .imm   = 0 })

/* Memory store, *(uint *) (dst_reg + off16) = src_reg */

#define BPF_STX_MEM(SIZE, DST, SRC, OFF)                        \
        ((struct bpf_insn) {                                    \
                .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,    \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = OFF,                                   \
                .imm   = 0 })

/* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */

#define BPF_STX_XADD(SIZE, DST, SRC, OFF)                       \
        ((struct bpf_insn) {                                    \
                .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD,   \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = OFF,                                   \
                .imm   = 0 })

/* Memory store, *(uint *) (dst_reg + off16) = imm32 */

#define BPF_ST_MEM(SIZE, DST, OFF, IMM)                         \
        ((struct bpf_insn) {                                    \
                .code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,     \
                .dst_reg = DST,                                 \
                .src_reg = 0,                                   \
                .off   = OFF,                                   \
                .imm   = IMM })

/* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */

#define BPF_JMP_REG(OP, DST, SRC, OFF)                          \
        ((struct bpf_insn) {                                    \
                .code  = BPF_JMP | BPF_OP(OP) | BPF_X,          \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = OFF,                                   \
                .imm   = 0 })

/* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */

#define BPF_JMP_IMM(OP, DST, IMM, OFF)                          \
        ((struct bpf_insn) {                                    \
                .code  = BPF_JMP | BPF_OP(OP) | BPF_K,          \
                .dst_reg = DST,                                 \
                .src_reg = 0,                                   \
                .off   = OFF,                                   \
                .imm   = IMM })

/* Like BPF_JMP_REG, but with 32-bit wide operands for comparison. */

#define BPF_JMP32_REG(OP, DST, SRC, OFF)                        \
        ((struct bpf_insn) {                                    \
                .code  = BPF_JMP32 | BPF_OP(OP) | BPF_X,        \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = OFF,                                   \
                .imm   = 0 })

/* Like BPF_JMP_IMM, but with 32-bit wide operands for comparison. */

#define BPF_JMP32_IMM(OP, DST, IMM, OFF)                        \
        ((struct bpf_insn) {                                    \
                .code  = BPF_JMP32 | BPF_OP(OP) | BPF_K,        \
                .dst_reg = DST,                                 \
                .src_reg = 0,                                   \
                .off   = OFF,                                   \
                .imm   = IMM })

/* Unconditional jumps, goto pc + off16 */

#define BPF_JMP_A(OFF)                                          \
        ((struct bpf_insn) {                                    \
                .code  = BPF_JMP | BPF_JA,                      \
                .dst_reg = 0,                                   \
                .src_reg = 0,                                   \
                .off   = OFF,                                   \
                .imm   = 0 })

/* Relative call */

#define BPF_CALL_REL(TGT)                                       \
        ((struct bpf_insn) {                                    \
                .code  = BPF_JMP | BPF_CALL,                    \
                .dst_reg = 0,                                   \
                .src_reg = BPF_PSEUDO_CALL,                     \
                .off   = 0,                                     \
                .imm   = TGT })

/* Function call */

#define BPF_CAST_CALL(x)                                        \
                ((u64 (*)(u64, u64, u64, u64, u64))(x))

#define BPF_EMIT_CALL(FUNC)                                     \
        ((struct bpf_insn) {                                    \
                .code  = BPF_JMP | BPF_CALL,                    \
                .dst_reg = 0,                                   \
                .src_reg = 0,                                   \
                .off   = 0,                                     \
                .imm   = ((FUNC) - __bpf_call_base) })

/* Raw code statement block */

#define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)                  \
        ((struct bpf_insn) {                                    \
                .code  = CODE,                                  \
                .dst_reg = DST,                                 \
                .src_reg = SRC,                                 \
                .off   = OFF,                                   \
                .imm   = IMM })

/* Program exit */

#define BPF_EXIT_INSN()                                         \
        ((struct bpf_insn) {                                    \
                .code  = BPF_JMP | BPF_EXIT,                    \
                .dst_reg = 0,                                   \
                .src_reg = 0,                                   \
                .off   = 0,                                     \
                .imm   = 0 })

/* Internal classic blocks for direct assignment */

#define __BPF_STMT(CODE, K)                                     \
        ((struct sock_filter) BPF_STMT(CODE, K))

#define __BPF_JUMP(CODE, K, JT, JF)                             \
        ((struct sock_filter) BPF_JUMP(CODE, K, JT, JF))

#define bytes_to_bpf_size(bytes)                                \
({                                                              \
        int bpf_size = -EINVAL;                                 \
                                                                \
        if (bytes == sizeof(u8))                                \
                bpf_size = BPF_B;                               \
        else if (bytes == sizeof(u16))                          \
                bpf_size = BPF_H;                               \
        else if (bytes == sizeof(u32))                          \
                bpf_size = BPF_W;                               \
        else if (bytes == sizeof(u64))                          \
                bpf_size = BPF_DW;                              \
                                                                \
        bpf_size;                                               \
})

#define bpf_size_to_bytes(bpf_size)                             \
({                                                              \
        int bytes = -EINVAL;                                    \
                                                                \
        if (bpf_size == BPF_B)                                  \
                bytes = sizeof(u8);                             \
        else if (bpf_size == BPF_H)                             \
                bytes = sizeof(u16);                            \
        else if (bpf_size == BPF_W)                             \
                bytes = sizeof(u32);                            \
        else if (bpf_size == BPF_DW)                            \
                bytes = sizeof(u64);                            \
                                                                \
        bytes;                                                  \
})

#define BPF_SIZEOF(type)                                        \
        ({                                                      \
                const int __size = bytes_to_bpf_size(sizeof(type)); \
                BUILD_BUG_ON(__size < 0);                       \
                __size;                                         \
        })

#define BPF_FIELD_SIZEOF(type, field)                           \
        ({                                                      \
                const int __size = bytes_to_bpf_size(sizeof_field(type, field)); \
                BUILD_BUG_ON(__size < 0);                       \
                __size;                                         \
        })

#define BPF_LDST_BYTES(insn)                                    \
        ({                                                      \
                const int __size = bpf_size_to_bytes(BPF_SIZE((insn)->code)); \
                WARN_ON(__size < 0);                            \
                __size;                                         \
        })

#define __BPF_MAP_0(m, v, ...) v
#define __BPF_MAP_1(m, v, t, a, ...) m(t, a)
#define __BPF_MAP_2(m, v, t, a, ...) m(t, a), __BPF_MAP_1(m, v, __VA_ARGS__)
#define __BPF_MAP_3(m, v, t, a, ...) m(t, a), __BPF_MAP_2(m, v, __VA_ARGS__)
#define __BPF_MAP_4(m, v, t, a, ...) m(t, a), __BPF_MAP_3(m, v, __VA_ARGS__)
#define __BPF_MAP_5(m, v, t, a, ...) m(t, a), __BPF_MAP_4(m, v, __VA_ARGS__)

#define __BPF_REG_0(...) __BPF_PAD(5)
#define __BPF_REG_1(...) __BPF_MAP(1, __VA_ARGS__), __BPF_PAD(4)
#define __BPF_REG_2(...) __BPF_MAP(2, __VA_ARGS__), __BPF_PAD(3)
#define __BPF_REG_3(...) __BPF_MAP(3, __VA_ARGS__), __BPF_PAD(2)
#define __BPF_REG_4(...) __BPF_MAP(4, __VA_ARGS__), __BPF_PAD(1)
#define __BPF_REG_5(...) __BPF_MAP(5, __VA_ARGS__)

#define __BPF_MAP(n, ...) __BPF_MAP_##n(__VA_ARGS__)
#define __BPF_REG(n, ...) __BPF_REG_##n(__VA_ARGS__)

#define __BPF_CAST(t, a)                                                       \
        (__force t)                                                            \
        (__force                                                               \
         typeof(__builtin_choose_expr(sizeof(t) == sizeof(unsigned long),      \
                                      (unsigned long)0, (t)0))) a
#define __BPF_V void
#define __BPF_N

#define __BPF_DECL_ARGS(t, a) t   a
#define __BPF_DECL_REGS(t, a) u64 a

#define __BPF_PAD(n)                                                           \
        __BPF_MAP(n, __BPF_DECL_ARGS, __BPF_N, u64, __ur_1, u64, __ur_2,       \
                  u64, __ur_3, u64, __ur_4, u64, __ur_5)

#define BPF_CALL_x(x, name, ...)                                               \
        static __always_inline                                                 \
        u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__));   \
        typedef u64 (*btf_##name)(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \
        u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__));         \
        u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__))          \
        {                                                                      \
                return ((btf_##name)____##name)(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\
        }                                                                      \
        static __always_inline                                                 \
        u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__))

#define BPF_CALL_0(name, ...)   BPF_CALL_x(0, name, __VA_ARGS__)
#define BPF_CALL_1(name, ...)   BPF_CALL_x(1, name, __VA_ARGS__)
#define BPF_CALL_2(name, ...)   BPF_CALL_x(2, name, __VA_ARGS__)
#define BPF_CALL_3(name, ...)   BPF_CALL_x(3, name, __VA_ARGS__)
#define BPF_CALL_4(name, ...)   BPF_CALL_x(4, name, __VA_ARGS__)
#define BPF_CALL_5(name, ...)   BPF_CALL_x(5, name, __VA_ARGS__)

#define bpf_ctx_range(TYPE, MEMBER)                                             \
        offsetof(TYPE, MEMBER) ... offsetofend(TYPE, MEMBER) - 1
#define bpf_ctx_range_till(TYPE, MEMBER1, MEMBER2)                              \
        offsetof(TYPE, MEMBER1) ... offsetofend(TYPE, MEMBER2) - 1
#if BITS_PER_LONG == 64
# define bpf_ctx_range_ptr(TYPE, MEMBER)                                        \
        offsetof(TYPE, MEMBER) ... offsetofend(TYPE, MEMBER) - 1
#else
# define bpf_ctx_range_ptr(TYPE, MEMBER)                                        \
        offsetof(TYPE, MEMBER) ... offsetof(TYPE, MEMBER) + 8 - 1
#endif /* BITS_PER_LONG == 64 */

#define bpf_target_off(TYPE, MEMBER, SIZE, PTR_SIZE)                            \
        ({                                                                      \
                BUILD_BUG_ON(sizeof_field(TYPE, MEMBER) != (SIZE));             \
                *(PTR_SIZE) = (SIZE);                                           \
                offsetof(TYPE, MEMBER);                                         \
        })

/* A struct sock_filter is architecture independent. */
struct compat_sock_fprog {
        u16             len;
        compat_uptr_t   filter; /* struct sock_filter * */
};

struct sock_fprog_kern {
        u16                     len;
        struct sock_filter      *filter;
};

/* Some arches need doubleword alignment for their instructions and/or data */
#define BPF_IMAGE_ALIGNMENT 8

struct bpf_binary_header {
        u32 pages;
        u8 image[] __aligned(BPF_IMAGE_ALIGNMENT);
};

struct bpf_prog {
        u16                     pages;          /* Number of allocated pages */
        u16                     jited:1,        /* Is our filter JIT'ed? */
                                jit_requested:1,/* archs need to JIT the prog */
                                gpl_compatible:1, /* Is filter GPL compatible? */
                                cb_access:1,    /* Is control block accessed? */
                                dst_needed:1,   /* Do we need dst entry? */
                                blinded:1,      /* Was blinded */
                                is_func:1,      /* program is a bpf function */
                                kprobe_override:1, /* Do we override a kprobe? */
                                has_callchain_buf:1, /* callchain buffer allocated? */
                                enforce_expected_attach_type:1, /* Enforce expected_attach_type checking at attach time */
                                call_get_stack:1; /* Do we call bpf_get_stack() or bpf_get_stackid() */
        enum bpf_prog_type      type;           /* Type of BPF program */
        enum bpf_attach_type    expected_attach_type; /* For some prog types */
        u32                     len;            /* Number of filter blocks */
        u32                     jited_len;      /* Size of jited insns in bytes */
        u8                      tag[BPF_TAG_SIZE];
        struct bpf_prog_aux     *aux;           /* Auxiliary fields */
        struct sock_fprog_kern  *orig_prog;     /* Original BPF program */
        unsigned int            (*bpf_func)(const void *ctx,
                                            const struct bpf_insn *insn);
        /* Instructions for interpreter */
        struct sock_filter      insns[0];
        struct bpf_insn         insnsi[];
};

struct sk_filter {
        refcount_t      refcnt;
        struct rcu_head rcu;
        struct bpf_prog *prog;
};

DECLARE_STATIC_KEY_FALSE(bpf_stats_enabled_key);

#define __BPF_PROG_RUN(prog, ctx, dfunc)        ({                      \
        u32 ret;                                                        \
        cant_migrate();                                                 \
        if (static_branch_unlikely(&bpf_stats_enabled_key)) {           \
                struct bpf_prog_stats *stats;                           \
                u64 start = sched_clock();                              \
                ret = dfunc(ctx, (prog)->insnsi, (prog)->bpf_func);     \
                stats = this_cpu_ptr(prog->aux->stats);                 \
                u64_stats_update_begin(&stats->syncp);                  \
                stats->cnt++;                                           \
                stats->nsecs += sched_clock() - start;                  \
                u64_stats_update_end(&stats->syncp);                    \
        } else {                                                        \
                ret = dfunc(ctx, (prog)->insnsi, (prog)->bpf_func);     \
        }                                                               \
        ret; })

#define BPF_PROG_RUN(prog, ctx)                                         \
        __BPF_PROG_RUN(prog, ctx, bpf_dispatcher_nop_func)

/*
 * Use in preemptible and therefore migratable context to make sure that
 * the execution of the BPF program runs on one CPU.
 *
 * This uses migrate_disable/enable() explicitly to document that the
 * invocation of a BPF program does not require reentrancy protection
 * against a BPF program which is invoked from a preempting task.
 *
 * For non RT enabled kernels migrate_disable/enable() maps to
 * preempt_disable/enable(), i.e. it disables also preemption.
 */
static inline u32 bpf_prog_run_pin_on_cpu(const struct bpf_prog *prog,
                                          const void *ctx)
{
        u32 ret;

        migrate_disable();
        ret = __BPF_PROG_RUN(prog, ctx, bpf_dispatcher_nop_func);
        migrate_enable();
        return ret;
}

#define BPF_SKB_CB_LEN QDISC_CB_PRIV_LEN

struct bpf_skb_data_end {
        struct qdisc_skb_cb qdisc_cb;
        void *data_meta;
        void *data_end;
};

struct bpf_redirect_info {
        u32 flags;
        u32 tgt_index;
        void *tgt_value;
        struct bpf_map *map;
        u32 kern_flags;
};

DECLARE_PER_CPU(struct bpf_redirect_info, bpf_redirect_info);

/* flags for bpf_redirect_info kern_flags */
#define BPF_RI_F_RF_NO_DIRECT   BIT(0)  /* no napi_direct on return_frame */

/* Compute the linear packet data range [data, data_end) which
 * will be accessed by various program types (cls_bpf, act_bpf,
 * lwt, ...). Subsystems allowing direct data access must (!)
 * ensure that cb[] area can be written to when BPF program is
 * invoked (otherwise cb[] save/restore is necessary).
 */
static inline void bpf_compute_data_pointers(struct sk_buff *skb)
{
        struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb;

        BUILD_BUG_ON(sizeof(*cb) > sizeof_field(struct sk_buff, cb));
        cb->data_meta = skb->data - skb_metadata_len(skb);
        cb->data_end  = skb->data + skb_headlen(skb);
}

/* Similar to bpf_compute_data_pointers(), except that save orginal
 * data in cb->data and cb->meta_data for restore.
 */
static inline void bpf_compute_and_save_data_end(
        struct sk_buff *skb, void **saved_data_end)
{
        struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb;

        *saved_data_end = cb->data_end;
        cb->data_end  = skb->data + skb_headlen(skb);
}

/* Restore data saved by bpf_compute_data_pointers(). */
static inline void bpf_restore_data_end(
        struct sk_buff *skb, void *saved_data_end)
{
        struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb;

        cb->data_end = saved_data_end;
}

static inline u8 *bpf_skb_cb(struct sk_buff *skb)
{
        /* eBPF programs may read/write skb->cb[] area to transfer meta
         * data between tail calls. Since this also needs to work with
         * tc, that scratch memory is mapped to qdisc_skb_cb's data area.
         *
         * In some socket filter cases, the cb unfortunately needs to be
         * saved/restored so that protocol specific skb->cb[] data won't
         * be lost. In any case, due to unpriviledged eBPF programs
         * attached to sockets, we need to clear the bpf_skb_cb() area
         * to not leak previous contents to user space.
         */
        BUILD_BUG_ON(sizeof_field(struct __sk_buff, cb) != BPF_SKB_CB_LEN);
        BUILD_BUG_ON(sizeof_field(struct __sk_buff, cb) !=
                     sizeof_field(struct qdisc_skb_cb, data));

        return qdisc_skb_cb(skb)->data;
}

/* Must be invoked with migration disabled */
static inline u32 __bpf_prog_run_save_cb(const struct bpf_prog *prog,
                                         struct sk_buff *skb)
{
        u8 *cb_data = bpf_skb_cb(skb);
        u8 cb_saved[BPF_SKB_CB_LEN];
        u32 res;

        if (unlikely(prog->cb_access)) {
                memcpy(cb_saved, cb_data, sizeof(cb_saved));
                memset(cb_data, 0, sizeof(cb_saved));
        }

        res = BPF_PROG_RUN(prog, skb);

        if (unlikely(prog->cb_access))
                memcpy(cb_data, cb_saved, sizeof(cb_saved));

        return res;
}

static inline u32 bpf_prog_run_save_cb(const struct bpf_prog *prog,
                                       struct sk_buff *skb)
{
        u32 res;

        migrate_disable();
        res = __bpf_prog_run_save_cb(prog, skb);
        migrate_enable();
        return res;
}

static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
                                        struct sk_buff *skb)
{
        u8 *cb_data = bpf_skb_cb(skb);
        u32 res;

        if (unlikely(prog->cb_access))
                memset(cb_data, 0, BPF_SKB_CB_LEN);

        res = bpf_prog_run_pin_on_cpu(prog, skb);
        return res;
}

DECLARE_BPF_DISPATCHER(xdp)

static __always_inline u32 bpf_prog_run_xdp(const struct bpf_prog *prog,
                                            struct xdp_buff *xdp)
{
        /* Caller needs to hold rcu_read_lock() (!), otherwise program
         * can be released while still running, or map elements could be
         * freed early while still having concurrent users. XDP fastpath
         * already takes rcu_read_lock() when fetching the program, so
         * it's not necessary here anymore.
         */
        return __BPF_PROG_RUN(prog, xdp, BPF_DISPATCHER_FUNC(xdp));
}

void bpf_prog_change_xdp(struct bpf_prog *prev_prog, struct bpf_prog *prog);

static inline u32 bpf_prog_insn_size(const struct bpf_prog *prog)
{
        return prog->len * sizeof(struct bpf_insn);
}

static inline u32 bpf_prog_tag_scratch_size(const struct bpf_prog *prog)
{
        return round_up(bpf_prog_insn_size(prog) +
                        sizeof(__be64) + 1, SHA1_BLOCK_SIZE);
}

static inline unsigned int bpf_prog_size(unsigned int proglen)
{
        return max(sizeof(struct bpf_prog),
                   offsetof(struct bpf_prog, insns[proglen]));
}

static inline bool bpf_prog_was_classic(const struct bpf_prog *prog)
{
        /* When classic BPF programs have been loaded and the arch
         * does not have a classic BPF JIT (anymore), they have been
         * converted via bpf_migrate_filter() to eBPF and thus always
         * have an unspec program type.
         */
        return prog->type == BPF_PROG_TYPE_UNSPEC;
}

static inline u32 bpf_ctx_off_adjust_machine(u32 size)
{
        const u32 size_machine = sizeof(unsigned long);

        if (size > size_machine && size % size_machine == 0)
                size = size_machine;

        return size;
}

static inline bool
bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default)
{
        return size <= size_default && (size & (size - 1)) == 0;
}

static inline u8
bpf_ctx_narrow_access_offset(u32 off, u32 size, u32 size_default)
{
        u8 access_off = off & (size_default - 1);

#ifdef __LITTLE_ENDIAN
        return access_off;
#else
        return size_default - (access_off + size);
#endif
}

#define bpf_ctx_wide_access_ok(off, size, type, field)                  \
        (size == sizeof(__u64) &&                                       \
        off >= offsetof(type, field) &&                                 \
        off + sizeof(__u64) <= offsetofend(type, field) &&              \
        off % sizeof(__u64) == 0)

#define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))

static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
{
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
        if (!fp->jited) {
                set_vm_flush_reset_perms(fp);
                set_memory_ro((unsigned long)fp, fp->pages);
        }
#endif
}

static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
{
        set_vm_flush_reset_perms(hdr);
        set_memory_ro((unsigned long)hdr, hdr->pages);
        set_memory_x((unsigned long)hdr, hdr->pages);
}

static inline struct bpf_binary_header *
bpf_jit_binary_hdr(const struct bpf_prog *fp)
{
        unsigned long real_start = (unsigned long)fp->bpf_func;
        unsigned long addr = real_start & PAGE_MASK;

        return (void *)addr;
}

int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap);
static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
{
        return sk_filter_trim_cap(sk, skb, 1);
}

struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err);
void bpf_prog_free(struct bpf_prog *fp);

bool bpf_opcode_in_insntable(u8 code);

void bpf_prog_free_linfo(struct bpf_prog *prog);
void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
                               const u32 *insn_to_jit_off);
int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog);
void bpf_prog_free_jited_linfo(struct bpf_prog *prog);
void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog);

struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags);
struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
                                  gfp_t gfp_extra_flags);
void __bpf_prog_free(struct bpf_prog *fp);

static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
{
        __bpf_prog_free(fp);
}

typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
                                       unsigned int flen);

int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
                              bpf_aux_classic_check_t trans, bool save_orig);
void bpf_prog_destroy(struct bpf_prog *fp);

int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
int sk_attach_bpf(u32 ufd, struct sock *sk);
int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk);
int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk);
void sk_reuseport_prog_free(struct bpf_prog *prog);
int sk_detach_filter(struct sock *sk);
int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
                  unsigned int len);

bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);

u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
#define __bpf_call_base_args \
        ((u64 (*)(u64, u64, u64, u64, u64, const struct bpf_insn *)) \
         __bpf_call_base)

struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog);
void bpf_jit_compile(struct bpf_prog *prog);
bool bpf_jit_needs_zext(void);
bool bpf_helper_changes_pkt_data(void *func);

static inline bool bpf_dump_raw_ok(const struct cred *cred)
{
        /* Reconstruction of call-sites is dependent on kallsyms,
         * thus make dump the same restriction.
         */
        return kallsyms_show_value(cred);
}

struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
                                       const struct bpf_insn *patch, u32 len);
int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt);

void bpf_clear_redirect_map(struct bpf_map *map);

static inline bool xdp_return_frame_no_direct(void)
{
        struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);

        return ri->kern_flags & BPF_RI_F_RF_NO_DIRECT;
}

static inline void xdp_set_return_frame_no_direct(void)
{
        struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);

        ri->kern_flags |= BPF_RI_F_RF_NO_DIRECT;
}

static inline void xdp_clear_return_frame_no_direct(void)
{
        struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);

        ri->kern_flags &= ~BPF_RI_F_RF_NO_DIRECT;
}

static inline int xdp_ok_fwd_dev(const struct net_device *fwd,
                                 unsigned int pktlen)
{
        unsigned int len;

        if (unlikely(!(fwd->flags & IFF_UP)))
                return -ENETDOWN;

        len = fwd->mtu + fwd->hard_header_len + VLAN_HLEN;
        if (pktlen > len)
                return -EMSGSIZE;

        return 0;
}

/* The pair of xdp_do_redirect and xdp_do_flush MUST be called in the
 * same cpu context. Further for best results no more than a single map
 * for the do_redirect/do_flush pair should be used. This limitation is
 * because we only track one map and force a flush when the map changes.
 * This does not appear to be a real limitation for existing software.
 */
int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,
                            struct xdp_buff *xdp, struct bpf_prog *prog);
int xdp_do_redirect(struct net_device *dev,
                    struct xdp_buff *xdp,
                    struct bpf_prog *prog);
void xdp_do_flush(void);

/* The xdp_do_flush_map() helper has been renamed to drop the _map suffix, as
 * it is no longer only flushing maps. Keep this define for compatibility
 * until all drivers are updated - do not use xdp_do_flush_map() in new code!
 */
#define xdp_do_flush_map xdp_do_flush

void bpf_warn_invalid_xdp_action(u32 act);

#ifdef CONFIG_INET
struct sock *bpf_run_sk_reuseport(struct sock_reuseport *reuse, struct sock *sk,
                                  struct bpf_prog *prog, struct sk_buff *skb,
                                  u32 hash);
#else
static inline struct sock *
bpf_run_sk_reuseport(struct sock_reuseport *reuse, struct sock *sk,
                     struct bpf_prog *prog, struct sk_buff *skb,
                     u32 hash)
{
        return NULL;
}
#endif

#ifdef CONFIG_BPF_JIT
extern int bpf_jit_enable;
extern int bpf_jit_harden;
extern int bpf_jit_kallsyms;
extern long bpf_jit_limit;

typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);

struct bpf_binary_header *
bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
                     unsigned int alignment,
                     bpf_jit_fill_hole_t bpf_fill_ill_insns);
void bpf_jit_binary_free(struct bpf_binary_header *hdr);
u64 bpf_jit_alloc_exec_limit(void);
void *bpf_jit_alloc_exec(unsigned long size);
void bpf_jit_free_exec(void *addr);
void bpf_jit_free(struct bpf_prog *fp);

int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
                                struct bpf_jit_poke_descriptor *poke);

int bpf_jit_get_func_addr(const struct bpf_prog *prog,
                          const struct bpf_insn *insn, bool extra_pass,
                          u64 *func_addr, bool *func_addr_fixed);

struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *fp);
void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other);

static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,

                                u32 pass, void *image)
{
        pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen,
               proglen, pass, image, current->comm, task_pid_nr(current));

        if (image)
                print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
                               16, 1, image, proglen, false);
}

static inline bool bpf_jit_is_ebpf(void)
{
# ifdef CONFIG_HAVE_EBPF_JIT
        return true;
# else
        return false;
# endif
}

static inline bool ebpf_jit_enabled(void)
{
        return bpf_jit_enable && bpf_jit_is_ebpf();
}

static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp)
{
        return fp->jited && bpf_jit_is_ebpf();
}

static inline bool bpf_jit_blinding_enabled(struct bpf_prog *prog)
{
        /* These are the prerequisites, should someone ever have the
         * idea to call blinding outside of them, we make sure to
         * bail out.
         */
        if (!bpf_jit_is_ebpf())
                return false;
        if (!prog->jit_requested)
                return false;
        if (!bpf_jit_harden)
                return false;
        if (bpf_jit_harden == 1 && capable(CAP_SYS_ADMIN))
                return false;

        return true;
}

static inline bool bpf_jit_kallsyms_enabled(void)
{
        /* There are a couple of corner cases where kallsyms should
         * not be enabled f.e. on hardening.
         */
        if (bpf_jit_harden)
                return false;
        if (!bpf_jit_kallsyms)
                return false;
        if (bpf_jit_kallsyms == 1)
                return true;

        return false;
}

const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
                                 unsigned long *off, char *sym);
bool is_bpf_text_address(unsigned long addr);
int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
                    char *sym);

static inline const char *
bpf_address_lookup(unsigned long addr, unsigned long *size,
                   unsigned long *off, char **modname, char *sym)
{
        const char *ret = __bpf_address_lookup(addr, size, off, sym);

        if (ret && modname)
                *modname = NULL;
        return ret;
}

void bpf_prog_kallsyms_add(struct bpf_prog *fp);
void bpf_prog_kallsyms_del(struct bpf_prog *fp);

#else /* CONFIG_BPF_JIT */

static inline bool ebpf_jit_enabled(void)
{
        return false;
}

static inline bool bpf_jit_blinding_enabled(struct bpf_prog *prog)
{
        return false;
}

static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp)
{
        return false;
}

static inline int
bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
                            struct bpf_jit_poke_descriptor *poke)
{
        return -ENOTSUPP;
}

static inline void bpf_jit_free(struct bpf_prog *fp)
{
        bpf_prog_unlock_free(fp);
}

static inline bool bpf_jit_kallsyms_enabled(void)
{
        return false;
}

static inline const char *
__bpf_address_lookup(unsigned long addr, unsigned long *size,
                     unsigned long *off, char *sym)
{
        return NULL;
}

static inline bool is_bpf_text_address(unsigned long addr)
{
        return false;
}

static inline int bpf_get_kallsym(unsigned int symnum, unsigned long *value,
                                  char *type, char *sym)
{
        return -ERANGE;
}

static inline const char *
bpf_address_lookup(unsigned long addr, unsigned long *size,
                   unsigned long *off, char **modname, char *sym)
{
        return NULL;
}

static inline void bpf_prog_kallsyms_add(struct bpf_prog *fp)
{
}

static inline void bpf_prog_kallsyms_del(struct bpf_prog *fp)
{
}

#endif /* CONFIG_BPF_JIT */

void bpf_prog_kallsyms_del_all(struct bpf_prog *fp);

#define BPF_ANC         BIT(15)

static inline bool bpf_needs_clear_a(const struct sock_filter *first)
{
        switch (first->code) {
        case BPF_RET | BPF_K:
        case BPF_LD | BPF_W | BPF_LEN:
                return false;

        case BPF_LD | BPF_W | BPF_ABS:
        case BPF_LD | BPF_H | BPF_ABS:
        case BPF_LD | BPF_B | BPF_ABS:
                if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
                        return true;
                return false;

        default:
                return true;
        }
}

static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
{
        BUG_ON(ftest->code & BPF_ANC);

        switch (ftest->code) {
        case BPF_LD | BPF_W | BPF_ABS:
        case BPF_LD | BPF_H | BPF_ABS:
        case BPF_LD | BPF_B | BPF_ABS:
#define BPF_ANCILLARY(CODE)     case SKF_AD_OFF + SKF_AD_##CODE:        \
                                return BPF_ANC | SKF_AD_##CODE
                switch (ftest->k) {
                BPF_ANCILLARY(PROTOCOL);
                BPF_ANCILLARY(PKTTYPE);
                BPF_ANCILLARY(IFINDEX);
                BPF_ANCILLARY(NLATTR);
                BPF_ANCILLARY(NLATTR_NEST);
                BPF_ANCILLARY(MARK);
                BPF_ANCILLARY(QUEUE);
                BPF_ANCILLARY(HATYPE);
                BPF_ANCILLARY(RXHASH);
                BPF_ANCILLARY(CPU);
                BPF_ANCILLARY(ALU_XOR_X);
                BPF_ANCILLARY(VLAN_TAG);
                BPF_ANCILLARY(VLAN_TAG_PRESENT);
                BPF_ANCILLARY(PAY_OFFSET);
                BPF_ANCILLARY(RANDOM);
                BPF_ANCILLARY(VLAN_TPID);
                }
                fallthrough;
        default:
                return ftest->code;
        }
}

void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
                                           int k, unsigned int size);

static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
                                     unsigned int size, void *buffer)
{
        if (k >= 0)
                return skb_header_pointer(skb, k, size, buffer);

        return bpf_internal_load_pointer_neg_helper(skb, k, size);
}

static inline int bpf_tell_extensions(void)
{
        return SKF_AD_MAX;
}

struct bpf_sock_addr_kern {
        struct sock *sk;
        struct sockaddr *uaddr;
        /* Temporary "register" to make indirect stores to nested structures
         * defined above. We need three registers to make such a store, but
         * only two (src and dst) are available at convert_ctx_access time
         */
        u64 tmp_reg;
        void *t_ctx;    /* Attach type specific context. */
};

struct bpf_sock_ops_kern {
        struct  sock *sk;
        u32     op;
        union {
                u32 args[4];
                u32 reply;
                u32 replylong[4];
        };
        u32     is_fullsock;
        u64     temp;                   /* temp and everything after is not
                                         * initialized to 0 before calling
                                         * the BPF program. New fields that
                                         * should be initialized to 0 should
                                         * be inserted before temp.
                                         * temp is scratch storage used by
                                         * sock_ops_convert_ctx_access
                                         * as temporary storage of a register.
                                         */
};

struct bpf_sysctl_kern {
        struct ctl_table_header *head;
        struct ctl_table *table;
        void *cur_val;
        size_t cur_len;
        void *new_val;
        size_t new_len;
        int new_updated;
        int write;
        loff_t *ppos;
        /* Temporary "register" for indirect stores to ppos. */
        u64 tmp_reg;
};

struct bpf_sockopt_kern {
        struct sock     *sk;
        u8              *optval;
        u8              *optval_end;
        s32             level;
        s32             optname;
        s32             optlen;
        s32             retval;
};

int copy_bpf_fprog_from_user(struct sock_fprog *dst, sockptr_t src, int len);

struct bpf_sk_lookup_kern {
        u16             family;
        u16             protocol;
        struct {
                __be32 saddr;
                __be32 daddr;
        } v4;
        struct {
                const struct in6_addr *saddr;
                const struct in6_addr *daddr;
        } v6;
        __be16          sport;
        u16             dport;
        struct sock     *selected_sk;
        bool            no_reuseport;
};

extern struct static_key_false bpf_sk_lookup_enabled;

/* Runners for BPF_SK_LOOKUP programs to invoke on socket lookup.
 *
 * Allowed return values for a BPF SK_LOOKUP program are SK_PASS and
 * SK_DROP. Their meaning is as follows:
 *
 *  SK_PASS && ctx.selected_sk != NULL: use selected_sk as lookup result
 *  SK_PASS && ctx.selected_sk == NULL: continue to htable-based socket lookup
 *  SK_DROP                           : terminate lookup with -ECONNREFUSED
 *
 * This macro aggregates return values and selected sockets from
 * multiple BPF programs according to following rules in order:
 *
 *  1. If any program returned SK_PASS and a non-NULL ctx.selected_sk,
 *     macro result is SK_PASS and last ctx.selected_sk is used.
 *  2. If any program returned SK_DROP return value,
 *     macro result is SK_DROP.
 *  3. Otherwise result is SK_PASS and ctx.selected_sk is NULL.
 *
 * Caller must ensure that the prog array is non-NULL, and that the
 * array as well as the programs it contains remain valid.
 */
#define BPF_PROG_SK_LOOKUP_RUN_ARRAY(array, ctx, func)                  \
        ({                                                              \
                struct bpf_sk_lookup_kern *_ctx = &(ctx);               \
                struct bpf_prog_array_item *_item;                      \
                struct sock *_selected_sk = NULL;                       \
                bool _no_reuseport = false;                             \
                struct bpf_prog *_prog;                                 \
                bool _all_pass = true;                                  \
                u32 _ret;                                               \
                                                                        \
                migrate_disable();                                      \
                _item = &(array)->items[0];                             \
                while ((_prog = READ_ONCE(_item->prog))) {              \
                        /* restore most recent selection */             \
                        _ctx->selected_sk = _selected_sk;               \
                        _ctx->no_reuseport = _no_reuseport;             \
                                                                        \
                        _ret = func(_prog, _ctx);                       \
                        if (_ret == SK_PASS && _ctx->selected_sk) {     \
                                /* remember last non-NULL socket */     \
                                _selected_sk = _ctx->selected_sk;       \
                                _no_reuseport = _ctx->no_reuseport;     \
                        } else if (_ret == SK_DROP && _all_pass) {      \
                                _all_pass = false;                      \
                        }                                               \
                        _item++;                                        \
                }                                                       \
                _ctx->selected_sk = _selected_sk;                       \
                _ctx->no_reuseport = _no_reuseport;                     \
                migrate_enable();                                       \
                _all_pass || _selected_sk ? SK_PASS : SK_DROP;          \
         })

static inline bool bpf_sk_lookup_run_v4(struct net *net, int protocol,
                                        const __be32 saddr, const __be16 sport,
                                        const __be32 daddr, const u16 dport,
                                        struct sock **psk)
{
        struct bpf_prog_array *run_array;
        struct sock *selected_sk = NULL;
        bool no_reuseport = false;

        rcu_read_lock();
        run_array = rcu_dereference(net->bpf.run_array[NETNS_BPF_SK_LOOKUP]);
        if (run_array) {
                struct bpf_sk_lookup_kern ctx = {
                        .family         = AF_INET,
                        .protocol       = protocol,
                        .v4.saddr       = saddr,
                        .v4.daddr       = daddr,
                        .sport          = sport,
                        .dport          = dport,
                };
                u32 act;

                act = BPF_PROG_SK_LOOKUP_RUN_ARRAY(run_array, ctx, BPF_PROG_RUN);
                if (act == SK_PASS) {
                        selected_sk = ctx.selected_sk;
                        no_reuseport = ctx.no_reuseport;
                } else {
                        selected_sk = ERR_PTR(-ECONNREFUSED);
                }
        }
        rcu_read_unlock();
        *psk = selected_sk;
        return no_reuseport;
}

#if IS_ENABLED(CONFIG_IPV6)
static inline bool bpf_sk_lookup_run_v6(struct net *net, int protocol,
                                        const struct in6_addr *saddr,
                                        const __be16 sport,
                                        const struct in6_addr *daddr,
                                        const u16 dport,
                                        struct sock **psk)
{
        struct bpf_prog_array *run_array;
        struct sock *selected_sk = NULL;
        bool no_reuseport = false;

        rcu_read_lock();
        run_array = rcu_dereference(net->bpf.run_array[NETNS_BPF_SK_LOOKUP]);
        if (run_array) {
                struct bpf_sk_lookup_kern ctx = {
                        .family         = AF_INET6,
                        .protocol       = protocol,
                        .v6.saddr       = saddr,
                        .v6.daddr       = daddr,
                        .sport          = sport,
                        .dport          = dport,
                };
                u32 act;

                act = BPF_PROG_SK_LOOKUP_RUN_ARRAY(run_array, ctx, BPF_PROG_RUN);
                if (act == SK_PASS) {
                        selected_sk = ctx.selected_sk;
                        no_reuseport = ctx.no_reuseport;
                } else {
                        selected_sk = ERR_PTR(-ECONNREFUSED);
                }
        }
        rcu_read_unlock();
        *psk = selected_sk;
        return no_reuseport;
}
#endif /* IS_ENABLED(CONFIG_IPV6) */

#endif /* __LINUX_FILTER_H__ */