LXR linux/tools/testing/selftests/bpf/progs/test_tc

   1// SPDX-License-Identifier: GPL-2.0
   2
   3/* In-place tunneling */
   4
   5#include <stdbool.h>
   6#include <string.h>
   7
   8#include <linux/stddef.h>
   9#include <linux/bpf.h>
  10#include <linux/if_ether.h>
  11#include <linux/in.h>
  12#include <linux/ip.h>
  13#include <linux/ipv6.h>
  14#include <linux/mpls.h>
  15#include <linux/tcp.h>
  16#include <linux/udp.h>
  17#include <linux/pkt_cls.h>
  18#include <linux/types.h>
  19
  20#include "bpf_endian.h"
  21#include "bpf_helpers.h"
  22
  23static const int cfg_port = 8000;
  24
  25static const int cfg_udp_src = 20000;
  26
  27#define UDP_PORT                5555
  28#define MPLS_OVER_UDP_PORT      6635
  29#define ETH_OVER_UDP_PORT       7777
  30
  31/* MPLS label 1000 with S bit (last label) set and ttl of 255. */
  32static const __u32 mpls_label = __bpf_constant_htonl(1000 << 12 |
  33                                                     MPLS_LS_S_MASK | 0xff);
  34
  35struct gre_hdr {
  36        __be16 flags;
  37        __be16 protocol;
  38} __attribute__((packed));
  39
  40union l4hdr {
  41        struct udphdr udp;
  42        struct gre_hdr gre;
  43};
  44
  45struct v4hdr {
  46        struct iphdr ip;
  47        union l4hdr l4hdr;
  48        __u8 pad[16];                   /* enough space for L2 header */
  49} __attribute__((packed));
  50
  51struct v6hdr {
  52        struct ipv6hdr ip;
  53        union l4hdr l4hdr;
  54        __u8 pad[16];                   /* enough space for L2 header */
  55} __attribute__((packed));
  56
  57static __always_inline void set_ipv4_csum(struct iphdr *iph)
  58{
  59        __u16 *iph16 = (__u16 *)iph;
  60        __u32 csum;
  61        int i;
  62
  63        iph->check = 0;
  64
  65#pragma clang loop unroll(full)
  66        for (i = 0, csum = 0; i < sizeof(*iph) >> 1; i++)
  67                csum += *iph16++;
  68
  69        iph->check = ~((csum & 0xffff) + (csum >> 16));
  70}
  71
  72static __always_inline int encap_ipv4(struct __sk_buff *skb, __u8 encap_proto,
  73                                      __u16 l2_proto)
  74{
  75        __u16 udp_dst = UDP_PORT;
  76        struct iphdr iph_inner;
  77        struct v4hdr h_outer;
  78        struct tcphdr tcph;
  79        int olen, l2_len;
  80        int tcp_off;
  81        __u64 flags;
  82
  83        /* Most tests encapsulate a packet into a tunnel with the same
  84         * network protocol, and derive the outer header fields from
  85         * the inner header.
  86         *
  87         * The 6in4 case tests different inner and outer protocols. As
  88         * the inner is ipv6, but the outer expects an ipv4 header as
  89         * input, manually build a struct iphdr based on the ipv6hdr.
  90         */
  91        if (encap_proto == IPPROTO_IPV6) {
  92                const __u32 saddr = (192 << 24) | (168 << 16) | (1 << 8) | 1;
  93                const __u32 daddr = (192 << 24) | (168 << 16) | (1 << 8) | 2;
  94                struct ipv6hdr iph6_inner;
  95
  96                /* Read the IPv6 header */
  97                if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph6_inner,
  98                                       sizeof(iph6_inner)) < 0)
  99                        return TC_ACT_OK;
 100
 101                /* Derive the IPv4 header fields from the IPv6 header */
 102                memset(&iph_inner, 0, sizeof(iph_inner));
 103                iph_inner.version = 4;
 104                iph_inner.ihl = 5;
 105                iph_inner.tot_len = bpf_htons(sizeof(iph6_inner) +
 106                                    bpf_ntohs(iph6_inner.payload_len));
 107                iph_inner.ttl = iph6_inner.hop_limit - 1;
 108                iph_inner.protocol = iph6_inner.nexthdr;
 109                iph_inner.saddr = __bpf_constant_htonl(saddr);
 110                iph_inner.daddr = __bpf_constant_htonl(daddr);
 111
 112                tcp_off = sizeof(iph6_inner);
 113        } else {
 114                if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
 115                                       sizeof(iph_inner)) < 0)
 116                        return TC_ACT_OK;
 117
 118                tcp_off = sizeof(iph_inner);
 119        }
 120
 121        /* filter only packets we want */
 122        if (iph_inner.ihl != 5 || iph_inner.protocol != IPPROTO_TCP)
 123                return TC_ACT_OK;
 124
 125        if (bpf_skb_load_bytes(skb, ETH_HLEN + tcp_off,
 126                               &tcph, sizeof(tcph)) < 0)
 127                return TC_ACT_OK;
 128
 129        if (tcph.dest != __bpf_constant_htons(cfg_port))
 130                return TC_ACT_OK;
 131
 132        olen = sizeof(h_outer.ip);
 133        l2_len = 0;
 134
 135        flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV4;
 136
 137        switch (l2_proto) {
 138        case ETH_P_MPLS_UC:
 139                l2_len = sizeof(mpls_label);
 140                udp_dst = MPLS_OVER_UDP_PORT;
 141                break;
 142        case ETH_P_TEB:
 143                l2_len = ETH_HLEN;
 144                udp_dst = ETH_OVER_UDP_PORT;
 145                break;
 146        }
 147        flags |= BPF_F_ADJ_ROOM_ENCAP_L2(l2_len);
 148
 149        switch (encap_proto) {
 150        case IPPROTO_GRE:
 151                flags |= BPF_F_ADJ_ROOM_ENCAP_L4_GRE;
 152                olen += sizeof(h_outer.l4hdr.gre);
 153                h_outer.l4hdr.gre.protocol = bpf_htons(l2_proto);
 154                h_outer.l4hdr.gre.flags = 0;
 155                break;
 156        case IPPROTO_UDP:
 157                flags |= BPF_F_ADJ_ROOM_ENCAP_L4_UDP;
 158                olen += sizeof(h_outer.l4hdr.udp);
 159                h_outer.l4hdr.udp.source = __bpf_constant_htons(cfg_udp_src);
 160                h_outer.l4hdr.udp.dest = bpf_htons(udp_dst);
 161                h_outer.l4hdr.udp.check = 0;
 162                h_outer.l4hdr.udp.len = bpf_htons(bpf_ntohs(iph_inner.tot_len) +
 163                                                  sizeof(h_outer.l4hdr.udp) +
 164                                                  l2_len);
 165                break;
 166        case IPPROTO_IPIP:
 167        case IPPROTO_IPV6:
 168                break;
 169        default:
 170                return TC_ACT_OK;
 171        }
 172
 173        /* add L2 encap (if specified) */
 174        switch (l2_proto) {
 175        case ETH_P_MPLS_UC:
 176                *((__u32 *)((__u8 *)&h_outer + olen)) = mpls_label;
 177                break;
 178        case ETH_P_TEB:
 179                if (bpf_skb_load_bytes(skb, 0, (__u8 *)&h_outer + olen,
 180                                       ETH_HLEN))
 181                        return TC_ACT_SHOT;
 182                break;
 183        }
 184        olen += l2_len;
 185
 186        /* add room between mac and network header */
 187        if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags))
 188                return TC_ACT_SHOT;
 189
 190        /* prepare new outer network header */
 191        h_outer.ip = iph_inner;
 192        h_outer.ip.tot_len = bpf_htons(olen +
 193                                       bpf_ntohs(h_outer.ip.tot_len));
 194        h_outer.ip.protocol = encap_proto;
 195
 196        set_ipv4_csum((void *)&h_outer.ip);
 197
 198        /* store new outer network header */
 199        if (bpf_skb_store_bytes(skb, ETH_HLEN, &h_outer, olen,
 200                                BPF_F_INVALIDATE_HASH) < 0)
 201                return TC_ACT_SHOT;
 202
 203        /* if changing outer proto type, update eth->h_proto */
 204        if (encap_proto == IPPROTO_IPV6) {
 205                struct ethhdr eth;
 206
 207                if (bpf_skb_load_bytes(skb, 0, &eth, sizeof(eth)) < 0)
 208                        return TC_ACT_SHOT;
 209                eth.h_proto = bpf_htons(ETH_P_IP);
 210                if (bpf_skb_store_bytes(skb, 0, &eth, sizeof(eth), 0) < 0)
 211                        return TC_ACT_SHOT;
 212        }
 213
 214        return TC_ACT_OK;
 215}
 216
 217static __always_inline int encap_ipv6(struct __sk_buff *skb, __u8 encap_proto,
 218                                      __u16 l2_proto)
 219{
 220        __u16 udp_dst = UDP_PORT;
 221        struct ipv6hdr iph_inner;
 222        struct v6hdr h_outer;
 223        struct tcphdr tcph;
 224        int olen, l2_len;
 225        __u16 tot_len;
 226        __u64 flags;
 227
 228        if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
 229                               sizeof(iph_inner)) < 0)
 230                return TC_ACT_OK;
 231
 232        /* filter only packets we want */
 233        if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(iph_inner),
 234                               &tcph, sizeof(tcph)) < 0)
 235                return TC_ACT_OK;
 236
 237        if (tcph.dest != __bpf_constant_htons(cfg_port))
 238                return TC_ACT_OK;
 239
 240        olen = sizeof(h_outer.ip);
 241        l2_len = 0;
 242
 243        flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV6;
 244
 245        switch (l2_proto) {
 246        case ETH_P_MPLS_UC:
 247                l2_len = sizeof(mpls_label);
 248                udp_dst = MPLS_OVER_UDP_PORT;
 249                break;
 250        case ETH_P_TEB:
 251                l2_len = ETH_HLEN;
 252                udp_dst = ETH_OVER_UDP_PORT;
 253                break;
 254        }
 255        flags |= BPF_F_ADJ_ROOM_ENCAP_L2(l2_len);
 256
 257        switch (encap_proto) {
 258        case IPPROTO_GRE:
 259                flags |= BPF_F_ADJ_ROOM_ENCAP_L4_GRE;
 260                olen += sizeof(h_outer.l4hdr.gre);
 261                h_outer.l4hdr.gre.protocol = bpf_htons(l2_proto);
 262                h_outer.l4hdr.gre.flags = 0;
 263                break;
 264        case IPPROTO_UDP:
 265                flags |= BPF_F_ADJ_ROOM_ENCAP_L4_UDP;
 266                olen += sizeof(h_outer.l4hdr.udp);
 267                h_outer.l4hdr.udp.source = __bpf_constant_htons(cfg_udp_src);
 268                h_outer.l4hdr.udp.dest = bpf_htons(udp_dst);
 269                tot_len = bpf_ntohs(iph_inner.payload_len) + sizeof(iph_inner) +
 270                          sizeof(h_outer.l4hdr.udp);
 271                h_outer.l4hdr.udp.check = 0;
 272                h_outer.l4hdr.udp.len = bpf_htons(tot_len);
 273                break;
 274        case IPPROTO_IPV6:
 275                break;
 276        default:
 277                return TC_ACT_OK;
 278        }
 279
 280        /* add L2 encap (if specified) */
 281        switch (l2_proto) {
 282        case ETH_P_MPLS_UC:
 283                *((__u32 *)((__u8 *)&h_outer + olen)) = mpls_label;
 284                break;
 285        case ETH_P_TEB:
 286                if (bpf_skb_load_bytes(skb, 0, (__u8 *)&h_outer + olen,
 287                                       ETH_HLEN))
 288                        return TC_ACT_SHOT;
 289                break;
 290        }
 291        olen += l2_len;
 292
 293        /* add room between mac and network header */
 294        if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags))
 295                return TC_ACT_SHOT;
 296
 297        /* prepare new outer network header */
 298        h_outer.ip = iph_inner;
 299        h_outer.ip.payload_len = bpf_htons(olen +
 300                                           bpf_ntohs(h_outer.ip.payload_len));
 301
 302        h_outer.ip.nexthdr = encap_proto;
 303
 304        /* store new outer network header */
 305        if (bpf_skb_store_bytes(skb, ETH_HLEN, &h_outer, olen,
 306                                BPF_F_INVALIDATE_HASH) < 0)
 307                return TC_ACT_SHOT;
 308
 309        return TC_ACT_OK;
 310}
 311
 312SEC("encap_ipip_none")
 313int __encap_ipip_none(struct __sk_buff *skb)
 314{
 315        if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
 316                return encap_ipv4(skb, IPPROTO_IPIP, ETH_P_IP);
 317        else
 318                return TC_ACT_OK;
 319}
 320
 321SEC("encap_gre_none")
 322int __encap_gre_none(struct __sk_buff *skb)
 323{
 324        if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
 325                return encap_ipv4(skb, IPPROTO_GRE, ETH_P_IP);
 326        else
 327                return TC_ACT_OK;
 328}
 329
 330SEC("encap_gre_mpls")
 331int __encap_gre_mpls(struct __sk_buff *skb)
 332{
 333        if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
 334                return encap_ipv4(skb, IPPROTO_GRE, ETH_P_MPLS_UC);
 335        else
 336                return TC_ACT_OK;
 337}
 338
 339SEC("encap_gre_eth")
 340int __encap_gre_eth(struct __sk_buff *skb)
 341{
 342        if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
 343                return encap_ipv4(skb, IPPROTO_GRE, ETH_P_TEB);
 344        else
 345                return TC_ACT_OK;
 346}
 347
 348SEC("encap_udp_none")
 349int __encap_udp_none(struct __sk_buff *skb)
 350{
 351        if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
 352                return encap_ipv4(skb, IPPROTO_UDP, ETH_P_IP);
 353        else
 354                return TC_ACT_OK;
 355}
 356
 357SEC("encap_udp_mpls")
 358int __encap_udp_mpls(struct __sk_buff *skb)
 359{
 360        if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
 361                return encap_ipv4(skb, IPPROTO_UDP, ETH_P_MPLS_UC);
 362        else
 363                return TC_ACT_OK;
 364}
 365
 366SEC("encap_udp_eth")
 367int __encap_udp_eth(struct __sk_buff *skb)
 368{
 369        if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
 370                return encap_ipv4(skb, IPPROTO_UDP, ETH_P_TEB);
 371        else
 372                return TC_ACT_OK;
 373}
 374
 375SEC("encap_sit_none")
 376int __encap_sit_none(struct __sk_buff *skb)
 377{
 378        if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
 379                return encap_ipv4(skb, IPPROTO_IPV6, ETH_P_IP);
 380        else
 381                return TC_ACT_OK;
 382}
 383
 384SEC("encap_ip6tnl_none")
 385int __encap_ip6tnl_none(struct __sk_buff *skb)
 386{
 387        if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
 388                return encap_ipv6(skb, IPPROTO_IPV6, ETH_P_IPV6);
 389        else
 390                return TC_ACT_OK;
 391}
 392
 393SEC("encap_ip6gre_none")
 394int __encap_ip6gre_none(struct __sk_buff *skb)
 395{
 396        if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
 397                return encap_ipv6(skb, IPPROTO_GRE, ETH_P_IPV6);
 398        else
 399                return TC_ACT_OK;
 400}
 401
 402SEC("encap_ip6gre_mpls")
 403int __encap_ip6gre_mpls(struct __sk_buff *skb)
 404{
 405        if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
 406                return encap_ipv6(skb, IPPROTO_GRE, ETH_P_MPLS_UC);
 407        else
 408                return TC_ACT_OK;
 409}
 410
 411SEC("encap_ip6gre_eth")
 412int __encap_ip6gre_eth(struct __sk_buff *skb)
 413{
 414        if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
 415                return encap_ipv6(skb, IPPROTO_GRE, ETH_P_TEB);
 416        else
 417                return TC_ACT_OK;
 418}
 419
 420SEC("encap_ip6udp_none")
 421int __encap_ip6udp_none(struct __sk_buff *skb)
 422{
 423        if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
 424                return encap_ipv6(skb, IPPROTO_UDP, ETH_P_IPV6);
 425        else
 426                return TC_ACT_OK;
 427}
 428
 429SEC("encap_ip6udp_mpls")
 430int __encap_ip6udp_mpls(struct __sk_buff *skb)
 431{
 432        if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
 433                return encap_ipv6(skb, IPPROTO_UDP, ETH_P_MPLS_UC);
 434        else
 435                return TC_ACT_OK;
 436}
 437
 438SEC("encap_ip6udp_eth")
 439int __encap_ip6udp_eth(struct __sk_buff *skb)
 440{
 441        if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
 442                return encap_ipv6(skb, IPPROTO_UDP, ETH_P_TEB);
 443        else
 444                return TC_ACT_OK;
 445}
 446
 447static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
 448{
 449        char buf[sizeof(struct v6hdr)];
 450        struct gre_hdr greh;
 451        struct udphdr udph;
 452        int olen = len;
 453
 454        switch (proto) {
 455        case IPPROTO_IPIP:
 456        case IPPROTO_IPV6:
 457                break;
 458        case IPPROTO_GRE:
 459                olen += sizeof(struct gre_hdr);
 460                if (bpf_skb_load_bytes(skb, off + len, &greh, sizeof(greh)) < 0)
 461                        return TC_ACT_OK;
 462                switch (bpf_ntohs(greh.protocol)) {
 463                case ETH_P_MPLS_UC:
 464                        olen += sizeof(mpls_label);
 465                        break;
 466                case ETH_P_TEB:
 467                        olen += ETH_HLEN;
 468                        break;
 469                }
 470                break;
 471        case IPPROTO_UDP:
 472                olen += sizeof(struct udphdr);
 473                if (bpf_skb_load_bytes(skb, off + len, &udph, sizeof(udph)) < 0)
 474                        return TC_ACT_OK;
 475                switch (bpf_ntohs(udph.dest)) {
 476                case MPLS_OVER_UDP_PORT:
 477                        olen += sizeof(mpls_label);
 478                        break;
 479                case ETH_OVER_UDP_PORT:
 480                        olen += ETH_HLEN;
 481                        break;
 482                }
 483                break;
 484        default:
 485                return TC_ACT_OK;
 486        }
 487
 488        if (bpf_skb_adjust_room(skb, -olen, BPF_ADJ_ROOM_MAC,
 489                                BPF_F_ADJ_ROOM_FIXED_GSO))
 490                return TC_ACT_SHOT;
 491
 492        return TC_ACT_OK;
 493}
 494
 495static int decap_ipv4(struct __sk_buff *skb)
 496{
 497        struct iphdr iph_outer;
 498
 499        if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer,
 500                               sizeof(iph_outer)) < 0)
 501                return TC_ACT_OK;
 502
 503        if (iph_outer.ihl != 5)
 504                return TC_ACT_OK;
 505
 506        return decap_internal(skb, ETH_HLEN, sizeof(iph_outer),
 507                              iph_outer.protocol);
 508}
 509
 510static int decap_ipv6(struct __sk_buff *skb)
 511{
 512        struct ipv6hdr iph_outer;
 513
 514        if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer,
 515                               sizeof(iph_outer)) < 0)
 516                return TC_ACT_OK;
 517
 518        return decap_internal(skb, ETH_HLEN, sizeof(iph_outer),
 519                              iph_outer.nexthdr);
 520}
 521
 522SEC("decap")
 523int decap_f(struct __sk_buff *skb)
 524{
 525        switch (skb->protocol) {
 526        case __bpf_constant_htons(ETH_P_IP):
 527                return decap_ipv4(skb);
 528        case __bpf_constant_htons(ETH_P_IPV6):
 529                return decap_ipv6(skb);
 530        default:
 531                /* does not match, ignore */
 532                return TC_ACT_OK;
 533        }
 534}
 535
 536char __license[] SEC("license") = "GPL";
 537