net/ipv6/seg6_local.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  SR-IPv6 implementation
   4  *
   5  *  Authors:
   6  *  David Lebrun <david.lebrun@uclouvain.be>
   7  *  eBPF support: Mathieu Xhonneux <m.xhonneux@gmail.com>
   8  */
   9
  10 #include <linux/types.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/net.h>
  13 #include <linux/module.h>
  14 #include <net/ip.h>
  15 #include <net/lwtunnel.h>
  16 #include <net/netevent.h>
  17 #include <net/netns/generic.h>
  18 #include <net/ip6_fib.h>
  19 #include <net/route.h>
  20 #include <net/seg6.h>
  21 #include <linux/seg6.h>
  22 #include <linux/seg6_local.h>
  23 #include <net/addrconf.h>
  24 #include <net/ip6_route.h>
  25 #include <net/dst_cache.h>
  26 #include <net/ip_tunnels.h>
  27 #ifdef CONFIG_IPV6_SEG6_HMAC
  28 #include <net/seg6_hmac.h>
  29 #endif
  30 #include <net/seg6_local.h>
  31 #include <linux/etherdevice.h>
  32 #include <linux/bpf.h>
  33
  34 struct seg6_local_lwt;
  35
  36 struct seg6_action_desc {
  37         int action;
  38         unsigned long attrs;
  39         int (*input)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
  40         int static_headroom;
  41 };
  42
  43 struct bpf_lwt_prog {
  44         struct bpf_prog *prog;
  45         char *name;
  46 };
  47
  48 struct seg6_local_lwt {
  49         int action;
  50         struct ipv6_sr_hdr *srh;
  51         int table;
  52         struct in_addr nh4;
  53         struct in6_addr nh6;
  54         int iif;
  55         int oif;
  56         struct bpf_lwt_prog bpf;
  57
  58         int headroom;
  59         struct seg6_action_desc *desc;
  60 };
  61
  62 static struct seg6_local_lwt *seg6_local_lwtunnel(struct lwtunnel_state *lwt)
  63 {
  64         return (struct seg6_local_lwt *)lwt->data;
  65 }
  66
  67 static struct ipv6_sr_hdr *get_srh(struct sk_buff *skb)
  68 {
  69         struct ipv6_sr_hdr *srh;
  70         int len, srhoff = 0;
  71
  72         if (ipv6_find_hdr(skb, &srhoff, IPPROTO_ROUTING, NULL, NULL) < 0)
  73                 return NULL;
  74
  75         if (!pskb_may_pull(skb, srhoff + sizeof(*srh)))
  76                 return NULL;
  77
  78         srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
  79
  80         len = (srh->hdrlen + 1) << 3;
  81
  82         if (!pskb_may_pull(skb, srhoff + len))
  83                 return NULL;
  84
  85         /* note that pskb_may_pull may change pointers in header;
  86          * for this reason it is necessary to reload them when needed.
  87          */
  88         srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
  89
  90         if (!seg6_validate_srh(srh, len))
  91                 return NULL;
  92
  93         return srh;
  94 }
  95
  96 static struct ipv6_sr_hdr *get_and_validate_srh(struct sk_buff *skb)
  97 {
  98         struct ipv6_sr_hdr *srh;
  99
 100         srh = get_srh(skb);
 101         if (!srh)
 102                 return NULL;
 103
 104         if (srh->segments_left == 0)
 105                 return NULL;
 106
 107 #ifdef CONFIG_IPV6_SEG6_HMAC
 108         if (!seg6_hmac_validate_skb(skb))
 109                 return NULL;
 110 #endif
 111
 112         return srh;
 113 }
 114
 115 static bool decap_and_validate(struct sk_buff *skb, int proto)
 116 {
 117         struct ipv6_sr_hdr *srh;
 118         unsigned int off = 0;
 119
 120         srh = get_srh(skb);
 121         if (srh && srh->segments_left > 0)
 122                 return false;
 123
 124 #ifdef CONFIG_IPV6_SEG6_HMAC
 125         if (srh && !seg6_hmac_validate_skb(skb))
 126                 return false;
 127 #endif
 128
 129         if (ipv6_find_hdr(skb, &off, proto, NULL, NULL) < 0)
 130                 return false;
 131
 132         if (!pskb_pull(skb, off))
 133                 return false;
 134
 135         skb_postpull_rcsum(skb, skb_network_header(skb), off);
 136
 137         skb_reset_network_header(skb);
 138         skb_reset_transport_header(skb);
 139         if (iptunnel_pull_offloads(skb))
 140                 return false;
 141
 142         return true;
 143 }
 144
 145 static void advance_nextseg(struct ipv6_sr_hdr *srh, struct in6_addr *daddr)
 146 {
 147         struct in6_addr *addr;
 148
 149         srh->segments_left--;
 150         addr = srh->segments + srh->segments_left;
 151         *daddr = *addr;
 152 }
 153
 154 static int
 155 seg6_lookup_any_nexthop(struct sk_buff *skb, struct in6_addr *nhaddr,
 156                         u32 tbl_id, bool local_delivery)
 157 {
 158         struct net *net = dev_net(skb->dev);
 159         struct ipv6hdr *hdr = ipv6_hdr(skb);
 160         int flags = RT6_LOOKUP_F_HAS_SADDR;
 161         struct dst_entry *dst = NULL;
 162         struct rt6_info *rt;
 163         struct flowi6 fl6;
 164         int dev_flags = 0;
 165
 166         fl6.flowi6_iif = skb->dev->ifindex;
 167         fl6.daddr = nhaddr ? *nhaddr : hdr->daddr;
 168         fl6.saddr = hdr->saddr;
 169         fl6.flowlabel = ip6_flowinfo(hdr);
 170         fl6.flowi6_mark = skb->mark;
 171         fl6.flowi6_proto = hdr->nexthdr;
 172
 173         if (nhaddr)
 174                 fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH;
 175
 176         if (!tbl_id) {
 177                 dst = ip6_route_input_lookup(net, skb->dev, &fl6, skb, flags);
 178         } else {
 179                 struct fib6_table *table;
 180
 181                 table = fib6_get_table(net, tbl_id);
 182                 if (!table)
 183                         goto out;
 184
 185                 rt = ip6_pol_route(net, table, 0, &fl6, skb, flags);
 186                 dst = &rt->dst;
 187         }
 188
 189         /* we want to discard traffic destined for local packet processing,
 190          * if @local_delivery is set to false.
 191          */
 192         if (!local_delivery)
 193                 dev_flags |= IFF_LOOPBACK;
 194
 195         if (dst && (dst->dev->flags & dev_flags) && !dst->error) {
 196                 dst_release(dst);
 197                 dst = NULL;
 198         }
 199
 200 out:
 201         if (!dst) {
 202                 rt = net->ipv6.ip6_blk_hole_entry;
 203                 dst = &rt->dst;
 204                 dst_hold(dst);
 205         }
 206
 207         skb_dst_drop(skb);
 208         skb_dst_set(skb, dst);
 209         return dst->error;
 210 }
 211
 212 int seg6_lookup_nexthop(struct sk_buff *skb,
 213                         struct in6_addr *nhaddr, u32 tbl_id)
 214 {
 215         return seg6_lookup_any_nexthop(skb, nhaddr, tbl_id, false);
 216 }
 217
 218 /* regular endpoint function */
 219 static int input_action_end(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 220 {
 221         struct ipv6_sr_hdr *srh;
 222
 223         srh = get_and_validate_srh(skb);
 224         if (!srh)
 225                 goto drop;
 226
 227         advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
 228
 229         seg6_lookup_nexthop(skb, NULL, 0);
 230
 231         return dst_input(skb);
 232
 233 drop:
 234         kfree_skb(skb);
 235         return -EINVAL;
 236 }
 237
 238 /* regular endpoint, and forward to specified nexthop */
 239 static int input_action_end_x(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 240 {
 241         struct ipv6_sr_hdr *srh;
 242
 243         srh = get_and_validate_srh(skb);
 244         if (!srh)
 245                 goto drop;
 246
 247         advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
 248
 249         seg6_lookup_nexthop(skb, &slwt->nh6, 0);
 250
 251         return dst_input(skb);
 252
 253 drop:
 254         kfree_skb(skb);
 255         return -EINVAL;
 256 }
 257
 258 static int input_action_end_t(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 259 {
 260         struct ipv6_sr_hdr *srh;
 261
 262         srh = get_and_validate_srh(skb);
 263         if (!srh)
 264                 goto drop;
 265
 266         advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
 267
 268         seg6_lookup_nexthop(skb, NULL, slwt->table);
 269
 270         return dst_input(skb);
 271
 272 drop:
 273         kfree_skb(skb);
 274         return -EINVAL;
 275 }
 276
 277 /* decapsulate and forward inner L2 frame on specified interface */
 278 static int input_action_end_dx2(struct sk_buff *skb,
 279                                 struct seg6_local_lwt *slwt)
 280 {
 281         struct net *net = dev_net(skb->dev);
 282         struct net_device *odev;
 283         struct ethhdr *eth;
 284
 285         if (!decap_and_validate(skb, NEXTHDR_NONE))
 286                 goto drop;
 287
 288         if (!pskb_may_pull(skb, ETH_HLEN))
 289                 goto drop;
 290
 291         skb_reset_mac_header(skb);
 292         eth = (struct ethhdr *)skb->data;
 293
 294         /* To determine the frame's protocol, we assume it is 802.3. This avoids
 295          * a call to eth_type_trans(), which is not really relevant for our
 296          * use case.
 297          */
 298         if (!eth_proto_is_802_3(eth->h_proto))
 299                 goto drop;
 300
 301         odev = dev_get_by_index_rcu(net, slwt->oif);
 302         if (!odev)
 303                 goto drop;
 304
 305         /* As we accept Ethernet frames, make sure the egress device is of
 306          * the correct type.
 307          */
 308         if (odev->type != ARPHRD_ETHER)
 309                 goto drop;
 310
 311         if (!(odev->flags & IFF_UP) || !netif_carrier_ok(odev))
 312                 goto drop;
 313
 314         skb_orphan(skb);
 315
 316         if (skb_warn_if_lro(skb))
 317                 goto drop;
 318
 319         skb_forward_csum(skb);
 320
 321         if (skb->len - ETH_HLEN > odev->mtu)
 322                 goto drop;
 323
 324         skb->dev = odev;
 325         skb->protocol = eth->h_proto;
 326
 327         return dev_queue_xmit(skb);
 328
 329 drop:
 330         kfree_skb(skb);
 331         return -EINVAL;
 332 }
 333
 334 /* decapsulate and forward to specified nexthop */
 335 static int input_action_end_dx6(struct sk_buff *skb,
 336                                 struct seg6_local_lwt *slwt)
 337 {
 338         struct in6_addr *nhaddr = NULL;
 339
 340         /* this function accepts IPv6 encapsulated packets, with either
 341          * an SRH with SL=0, or no SRH.
 342          */
 343
 344         if (!decap_and_validate(skb, IPPROTO_IPV6))
 345                 goto drop;
 346
 347         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 348                 goto drop;
 349
 350         /* The inner packet is not associated to any local interface,
 351          * so we do not call netif_rx().
 352          *
 353          * If slwt->nh6 is set to ::, then lookup the nexthop for the
 354          * inner packet's DA. Otherwise, use the specified nexthop.
 355          */
 356
 357         if (!ipv6_addr_any(&slwt->nh6))
 358                 nhaddr = &slwt->nh6;
 359
 360         skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 361
 362         seg6_lookup_nexthop(skb, nhaddr, 0);
 363
 364         return dst_input(skb);
 365 drop:
 366         kfree_skb(skb);
 367         return -EINVAL;
 368 }
 369
 370 static int input_action_end_dx4(struct sk_buff *skb,
 371                                 struct seg6_local_lwt *slwt)
 372 {
 373         struct iphdr *iph;
 374         __be32 nhaddr;
 375         int err;
 376
 377         if (!decap_and_validate(skb, IPPROTO_IPIP))
 378                 goto drop;
 379
 380         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 381                 goto drop;
 382
 383         skb->protocol = htons(ETH_P_IP);
 384
 385         iph = ip_hdr(skb);
 386
 387         nhaddr = slwt->nh4.s_addr ?: iph->daddr;
 388
 389         skb_dst_drop(skb);
 390
 391         skb_set_transport_header(skb, sizeof(struct iphdr));
 392
 393         err = ip_route_input(skb, nhaddr, iph->saddr, 0, skb->dev);
 394         if (err)
 395                 goto drop;
 396
 397         return dst_input(skb);
 398
 399 drop:
 400         kfree_skb(skb);
 401         return -EINVAL;
 402 }
 403
 404 static int input_action_end_dt6(struct sk_buff *skb,
 405                                 struct seg6_local_lwt *slwt)
 406 {
 407         if (!decap_and_validate(skb, IPPROTO_IPV6))
 408                 goto drop;
 409
 410         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 411                 goto drop;
 412
 413         skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 414
 415         seg6_lookup_any_nexthop(skb, NULL, slwt->table, true);
 416
 417         return dst_input(skb);
 418
 419 drop:
 420         kfree_skb(skb);
 421         return -EINVAL;
 422 }
 423
 424 /* push an SRH on top of the current one */
 425 static int input_action_end_b6(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 426 {
 427         struct ipv6_sr_hdr *srh;
 428         int err = -EINVAL;
 429
 430         srh = get_and_validate_srh(skb);
 431         if (!srh)
 432                 goto drop;
 433
 434         err = seg6_do_srh_inline(skb, slwt->srh);
 435         if (err)
 436                 goto drop;
 437
 438         ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 439         skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 440
 441         seg6_lookup_nexthop(skb, NULL, 0);
 442
 443         return dst_input(skb);
 444
 445 drop:
 446         kfree_skb(skb);
 447         return err;
 448 }
 449
 450 /* encapsulate within an outer IPv6 header and a specified SRH */
 451 static int input_action_end_b6_encap(struct sk_buff *skb,
 452                                      struct seg6_local_lwt *slwt)
 453 {
 454         struct ipv6_sr_hdr *srh;
 455         int err = -EINVAL;
 456
 457         srh = get_and_validate_srh(skb);
 458         if (!srh)
 459                 goto drop;
 460
 461         advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
 462
 463         skb_reset_inner_headers(skb);
 464         skb->encapsulation = 1;
 465
 466         err = seg6_do_srh_encap(skb, slwt->srh, IPPROTO_IPV6);
 467         if (err)
 468                 goto drop;
 469
 470         ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 471         skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 472
 473         seg6_lookup_nexthop(skb, NULL, 0);
 474
 475         return dst_input(skb);
 476
 477 drop:
 478         kfree_skb(skb);
 479         return err;
 480 }
 481
 482 DEFINE_PER_CPU(struct seg6_bpf_srh_state, seg6_bpf_srh_states);
 483
 484 bool seg6_bpf_has_valid_srh(struct sk_buff *skb)
 485 {
 486         struct seg6_bpf_srh_state *srh_state =
 487                 this_cpu_ptr(&seg6_bpf_srh_states);
 488         struct ipv6_sr_hdr *srh = srh_state->srh;
 489
 490         if (unlikely(srh == NULL))
 491                 return false;
 492
 493         if (unlikely(!srh_state->valid)) {
 494                 if ((srh_state->hdrlen & 7) != 0)
 495                         return false;
 496
 497                 srh->hdrlen = (u8)(srh_state->hdrlen >> 3);
 498                 if (!seg6_validate_srh(srh, (srh->hdrlen + 1) << 3))
 499                         return false;
 500
 501                 srh_state->valid = true;
 502         }
 503
 504         return true;
 505 }
 506
 507 static int input_action_end_bpf(struct sk_buff *skb,
 508                                 struct seg6_local_lwt *slwt)
 509 {
 510         struct seg6_bpf_srh_state *srh_state =
 511                 this_cpu_ptr(&seg6_bpf_srh_states);
 512         struct ipv6_sr_hdr *srh;
 513         int ret;
 514
 515         srh = get_and_validate_srh(skb);
 516         if (!srh) {
 517                 kfree_skb(skb);
 518                 return -EINVAL;
 519         }
 520         advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
 521
 522         /* preempt_disable is needed to protect the per-CPU buffer srh_state,
 523          * which is also accessed by the bpf_lwt_seg6_* helpers
 524          */
 525         preempt_disable();
 526         srh_state->srh = srh;
 527         srh_state->hdrlen = srh->hdrlen << 3;
 528         srh_state->valid = true;
 529
 530         rcu_read_lock();
 531         bpf_compute_data_pointers(skb);
 532         ret = bpf_prog_run_save_cb(slwt->bpf.prog, skb);
 533         rcu_read_unlock();
 534
 535         switch (ret) {
 536         case BPF_OK:
 537         case BPF_REDIRECT:
 538                 break;
 539         case BPF_DROP:
 540                 goto drop;
 541         default:
 542                 pr_warn_once("bpf-seg6local: Illegal return value %u\n", ret);
 543                 goto drop;
 544         }
 545
 546         if (srh_state->srh && !seg6_bpf_has_valid_srh(skb))
 547                 goto drop;
 548
 549         preempt_enable();
 550         if (ret != BPF_REDIRECT)
 551                 seg6_lookup_nexthop(skb, NULL, 0);
 552
 553         return dst_input(skb);
 554
 555 drop:
 556         preempt_enable();
 557         kfree_skb(skb);
 558         return -EINVAL;
 559 }
 560
 561 static struct seg6_action_desc seg6_action_table[] = {
 562         {
 563                 .action         = SEG6_LOCAL_ACTION_END,
 564                 .attrs          = 0,
 565                 .input          = input_action_end,
 566         },
 567         {
 568                 .action         = SEG6_LOCAL_ACTION_END_X,
 569                 .attrs          = (1 << SEG6_LOCAL_NH6),
 570                 .input          = input_action_end_x,
 571         },
 572         {
 573                 .action         = SEG6_LOCAL_ACTION_END_T,
 574                 .attrs          = (1 << SEG6_LOCAL_TABLE),
 575                 .input          = input_action_end_t,
 576         },
 577         {
 578                 .action         = SEG6_LOCAL_ACTION_END_DX2,
 579                 .attrs          = (1 << SEG6_LOCAL_OIF),
 580                 .input          = input_action_end_dx2,
 581         },
 582         {
 583                 .action         = SEG6_LOCAL_ACTION_END_DX6,
 584                 .attrs          = (1 << SEG6_LOCAL_NH6),
 585                 .input          = input_action_end_dx6,
 586         },
 587         {
 588                 .action         = SEG6_LOCAL_ACTION_END_DX4,
 589                 .attrs          = (1 << SEG6_LOCAL_NH4),
 590                 .input          = input_action_end_dx4,
 591         },
 592         {
 593                 .action         = SEG6_LOCAL_ACTION_END_DT6,
 594                 .attrs          = (1 << SEG6_LOCAL_TABLE),
 595                 .input          = input_action_end_dt6,
 596         },
 597         {
 598                 .action         = SEG6_LOCAL_ACTION_END_B6,
 599                 .attrs          = (1 << SEG6_LOCAL_SRH),
 600                 .input          = input_action_end_b6,
 601         },
 602         {
 603                 .action         = SEG6_LOCAL_ACTION_END_B6_ENCAP,
 604                 .attrs          = (1 << SEG6_LOCAL_SRH),
 605                 .input          = input_action_end_b6_encap,
 606                 .static_headroom        = sizeof(struct ipv6hdr),
 607         },
 608         {
 609                 .action         = SEG6_LOCAL_ACTION_END_BPF,
 610                 .attrs          = (1 << SEG6_LOCAL_BPF),
 611                 .input          = input_action_end_bpf,
 612         },
 613
 614 };
 615
 616 static struct seg6_action_desc *__get_action_desc(int action)
 617 {
 618         struct seg6_action_desc *desc;
 619         int i, count;
 620
 621         count = ARRAY_SIZE(seg6_action_table);
 622         for (i = 0; i < count; i++) {
 623                 desc = &seg6_action_table[i];
 624                 if (desc->action == action)
 625                         return desc;
 626         }
 627
 628         return NULL;
 629 }
 630
 631 static int seg6_local_input(struct sk_buff *skb)
 632 {
 633         struct dst_entry *orig_dst = skb_dst(skb);
 634         struct seg6_action_desc *desc;
 635         struct seg6_local_lwt *slwt;
 636
 637         if (skb->protocol != htons(ETH_P_IPV6)) {
 638                 kfree_skb(skb);
 639                 return -EINVAL;
 640         }
 641
 642         slwt = seg6_local_lwtunnel(orig_dst->lwtstate);
 643         desc = slwt->desc;
 644
 645         return desc->input(skb, slwt);
 646 }
 647
 648 static const struct nla_policy seg6_local_policy[SEG6_LOCAL_MAX + 1] = {
 649         [SEG6_LOCAL_ACTION]     = { .type = NLA_U32 },
 650         [SEG6_LOCAL_SRH]        = { .type = NLA_BINARY },
 651         [SEG6_LOCAL_TABLE]      = { .type = NLA_U32 },
 652         [SEG6_LOCAL_NH4]        = { .type = NLA_BINARY,
 653                                     .len = sizeof(struct in_addr) },
 654         [SEG6_LOCAL_NH6]        = { .type = NLA_BINARY,
 655                                     .len = sizeof(struct in6_addr) },
 656         [SEG6_LOCAL_IIF]        = { .type = NLA_U32 },
 657         [SEG6_LOCAL_OIF]        = { .type = NLA_U32 },
 658         [SEG6_LOCAL_BPF]        = { .type = NLA_NESTED },
 659 };
 660
 661 static int parse_nla_srh(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 662 {
 663         struct ipv6_sr_hdr *srh;
 664         int len;
 665
 666         srh = nla_data(attrs[SEG6_LOCAL_SRH]);
 667         len = nla_len(attrs[SEG6_LOCAL_SRH]);
 668
 669         /* SRH must contain at least one segment */
 670         if (len < sizeof(*srh) + sizeof(struct in6_addr))
 671                 return -EINVAL;
 672
 673         if (!seg6_validate_srh(srh, len))
 674                 return -EINVAL;
 675
 676         slwt->srh = kmemdup(srh, len, GFP_KERNEL);
 677         if (!slwt->srh)
 678                 return -ENOMEM;
 679
 680         slwt->headroom += len;
 681
 682         return 0;
 683 }
 684
 685 static int put_nla_srh(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 686 {
 687         struct ipv6_sr_hdr *srh;
 688         struct nlattr *nla;
 689         int len;
 690
 691         srh = slwt->srh;
 692         len = (srh->hdrlen + 1) << 3;
 693
 694         nla = nla_reserve(skb, SEG6_LOCAL_SRH, len);
 695         if (!nla)
 696                 return -EMSGSIZE;
 697
 698         memcpy(nla_data(nla), srh, len);
 699
 700         return 0;
 701 }
 702
 703 static int cmp_nla_srh(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
 704 {
 705         int len = (a->srh->hdrlen + 1) << 3;
 706
 707         if (len != ((b->srh->hdrlen + 1) << 3))
 708                 return 1;
 709
 710         return memcmp(a->srh, b->srh, len);
 711 }
 712
 713 static int parse_nla_table(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 714 {
 715         slwt->table = nla_get_u32(attrs[SEG6_LOCAL_TABLE]);
 716
 717         return 0;
 718 }
 719
 720 static int put_nla_table(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 721 {
 722         if (nla_put_u32(skb, SEG6_LOCAL_TABLE, slwt->table))
 723                 return -EMSGSIZE;
 724
 725         return 0;
 726 }
 727
 728 static int cmp_nla_table(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
 729 {
 730         if (a->table != b->table)
 731                 return 1;
 732
 733         return 0;
 734 }
 735
 736 static int parse_nla_nh4(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 737 {
 738         memcpy(&slwt->nh4, nla_data(attrs[SEG6_LOCAL_NH4]),
 739                sizeof(struct in_addr));
 740
 741         return 0;
 742 }
 743
 744 static int put_nla_nh4(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 745 {
 746         struct nlattr *nla;
 747
 748         nla = nla_reserve(skb, SEG6_LOCAL_NH4, sizeof(struct in_addr));
 749         if (!nla)
 750                 return -EMSGSIZE;
 751
 752         memcpy(nla_data(nla), &slwt->nh4, sizeof(struct in_addr));
 753
 754         return 0;
 755 }
 756
 757 static int cmp_nla_nh4(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
 758 {
 759         return memcmp(&a->nh4, &b->nh4, sizeof(struct in_addr));
 760 }
 761
 762 static int parse_nla_nh6(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 763 {
 764         memcpy(&slwt->nh6, nla_data(attrs[SEG6_LOCAL_NH6]),
 765                sizeof(struct in6_addr));
 766
 767         return 0;
 768 }
 769
 770 static int put_nla_nh6(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 771 {
 772         struct nlattr *nla;
 773
 774         nla = nla_reserve(skb, SEG6_LOCAL_NH6, sizeof(struct in6_addr));
 775         if (!nla)
 776                 return -EMSGSIZE;
 777
 778         memcpy(nla_data(nla), &slwt->nh6, sizeof(struct in6_addr));
 779
 780         return 0;
 781 }
 782
 783 static int cmp_nla_nh6(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
 784 {
 785         return memcmp(&a->nh6, &b->nh6, sizeof(struct in6_addr));
 786 }
 787
 788 static int parse_nla_iif(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 789 {
 790         slwt->iif = nla_get_u32(attrs[SEG6_LOCAL_IIF]);
 791
 792         return 0;
 793 }
 794
 795 static int put_nla_iif(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 796 {
 797         if (nla_put_u32(skb, SEG6_LOCAL_IIF, slwt->iif))
 798                 return -EMSGSIZE;
 799
 800         return 0;
 801 }
 802
 803 static int cmp_nla_iif(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
 804 {
 805         if (a->iif != b->iif)
 806                 return 1;
 807
 808         return 0;
 809 }
 810
 811 static int parse_nla_oif(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 812 {
 813         slwt->oif = nla_get_u32(attrs[SEG6_LOCAL_OIF]);
 814
 815         return 0;
 816 }
 817
 818 static int put_nla_oif(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 819 {
 820         if (nla_put_u32(skb, SEG6_LOCAL_OIF, slwt->oif))
 821                 return -EMSGSIZE;
 822
 823         return 0;
 824 }
 825
 826 static int cmp_nla_oif(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
 827 {
 828         if (a->oif != b->oif)
 829                 return 1;
 830
 831         return 0;
 832 }
 833
 834 #define MAX_PROG_NAME 256
 835 static const struct nla_policy bpf_prog_policy[SEG6_LOCAL_BPF_PROG_MAX + 1] = {
 836         [SEG6_LOCAL_BPF_PROG]      = { .type = NLA_U32, },
 837         [SEG6_LOCAL_BPF_PROG_NAME] = { .type = NLA_NUL_STRING,
 838                                        .len = MAX_PROG_NAME },
 839 };
 840
 841 static int parse_nla_bpf(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 842 {
 843         struct nlattr *tb[SEG6_LOCAL_BPF_PROG_MAX + 1];
 844         struct bpf_prog *p;
 845         int ret;
 846         u32 fd;
 847
 848         ret = nla_parse_nested_deprecated(tb, SEG6_LOCAL_BPF_PROG_MAX,
 849                                           attrs[SEG6_LOCAL_BPF],
 850                                           bpf_prog_policy, NULL);
 851         if (ret < 0)
 852                 return ret;
 853
 854         if (!tb[SEG6_LOCAL_BPF_PROG] || !tb[SEG6_LOCAL_BPF_PROG_NAME])
 855                 return -EINVAL;
 856
 857         slwt->bpf.name = nla_memdup(tb[SEG6_LOCAL_BPF_PROG_NAME], GFP_KERNEL);
 858         if (!slwt->bpf.name)
 859                 return -ENOMEM;
 860
 861         fd = nla_get_u32(tb[SEG6_LOCAL_BPF_PROG]);
 862         p = bpf_prog_get_type(fd, BPF_PROG_TYPE_LWT_SEG6LOCAL);
 863         if (IS_ERR(p)) {
 864                 kfree(slwt->bpf.name);
 865                 return PTR_ERR(p);
 866         }
 867
 868         slwt->bpf.prog = p;
 869         return 0;
 870 }
 871
 872 static int put_nla_bpf(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 873 {
 874         struct nlattr *nest;
 875
 876         if (!slwt->bpf.prog)
 877                 return 0;
 878
 879         nest = nla_nest_start_noflag(skb, SEG6_LOCAL_BPF);
 880         if (!nest)
 881                 return -EMSGSIZE;
 882
 883         if (nla_put_u32(skb, SEG6_LOCAL_BPF_PROG, slwt->bpf.prog->aux->id))
 884                 return -EMSGSIZE;
 885
 886         if (slwt->bpf.name &&
 887             nla_put_string(skb, SEG6_LOCAL_BPF_PROG_NAME, slwt->bpf.name))
 888                 return -EMSGSIZE;
 889
 890         return nla_nest_end(skb, nest);
 891 }
 892
 893 static int cmp_nla_bpf(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
 894 {
 895         if (!a->bpf.name && !b->bpf.name)
 896                 return 0;
 897
 898         if (!a->bpf.name || !b->bpf.name)
 899                 return 1;
 900
 901         return strcmp(a->bpf.name, b->bpf.name);
 902 }
 903
 904 struct seg6_action_param {
 905         int (*parse)(struct nlattr **attrs, struct seg6_local_lwt *slwt);
 906         int (*put)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
 907         int (*cmp)(struct seg6_local_lwt *a, struct seg6_local_lwt *b);
 908 };
 909
 910 static struct seg6_action_param seg6_action_params[SEG6_LOCAL_MAX + 1] = {
 911         [SEG6_LOCAL_SRH]        = { .parse = parse_nla_srh,
 912                                     .put = put_nla_srh,
 913                                     .cmp = cmp_nla_srh },
 914
 915         [SEG6_LOCAL_TABLE]      = { .parse = parse_nla_table,
 916                                     .put = put_nla_table,
 917                                     .cmp = cmp_nla_table },
 918
 919         [SEG6_LOCAL_NH4]        = { .parse = parse_nla_nh4,
 920                                     .put = put_nla_nh4,
 921                                     .cmp = cmp_nla_nh4 },
 922
 923         [SEG6_LOCAL_NH6]        = { .parse = parse_nla_nh6,
 924                                     .put = put_nla_nh6,
 925                                     .cmp = cmp_nla_nh6 },
 926
 927         [SEG6_LOCAL_IIF]        = { .parse = parse_nla_iif,
 928                                     .put = put_nla_iif,
 929                                     .cmp = cmp_nla_iif },
 930
 931         [SEG6_LOCAL_OIF]        = { .parse = parse_nla_oif,
 932                                     .put = put_nla_oif,
 933                                     .cmp = cmp_nla_oif },
 934
 935         [SEG6_LOCAL_BPF]        = { .parse = parse_nla_bpf,
 936                                     .put = put_nla_bpf,
 937                                     .cmp = cmp_nla_bpf },
 938
 939 };
 940
 941 static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 942 {
 943         struct seg6_action_param *param;
 944         struct seg6_action_desc *desc;
 945         int i, err;
 946
 947         desc = __get_action_desc(slwt->action);
 948         if (!desc)
 949                 return -EINVAL;
 950
 951         if (!desc->input)
 952                 return -EOPNOTSUPP;
 953
 954         slwt->desc = desc;
 955         slwt->headroom += desc->static_headroom;
 956
 957         for (i = 0; i < SEG6_LOCAL_MAX + 1; i++) {
 958                 if (desc->attrs & (1 << i)) {
 959                         if (!attrs[i])
 960                                 return -EINVAL;
 961
 962                         param = &seg6_action_params[i];
 963
 964                         err = param->parse(attrs, slwt);
 965                         if (err < 0)
 966                                 return err;
 967                 }
 968         }
 969
 970         return 0;
 971 }
 972
 973 static int seg6_local_build_state(struct nlattr *nla, unsigned int family,
 974                                   const void *cfg, struct lwtunnel_state **ts,
 975                                   struct netlink_ext_ack *extack)
 976 {
 977         struct nlattr *tb[SEG6_LOCAL_MAX + 1];
 978         struct lwtunnel_state *newts;
 979         struct seg6_local_lwt *slwt;
 980         int err;
 981
 982         if (family != AF_INET6)
 983                 return -EINVAL;
 984
 985         err = nla_parse_nested_deprecated(tb, SEG6_LOCAL_MAX, nla,
 986                                           seg6_local_policy, extack);
 987
 988         if (err < 0)
 989                 return err;
 990
 991         if (!tb[SEG6_LOCAL_ACTION])
 992                 return -EINVAL;
 993
 994         newts = lwtunnel_state_alloc(sizeof(*slwt));
 995         if (!newts)
 996                 return -ENOMEM;
 997
 998         slwt = seg6_local_lwtunnel(newts);
 999         slwt->action = nla_get_u32(tb[SEG6_LOCAL_ACTION]);
1000
1001         err = parse_nla_action(tb, slwt);
1002         if (err < 0)
1003                 goto out_free;
1004
1005         newts->type = LWTUNNEL_ENCAP_SEG6_LOCAL;
1006         newts->flags = LWTUNNEL_STATE_INPUT_REDIRECT;
1007         newts->headroom = slwt->headroom;
1008
1009         *ts = newts;
1010
1011         return 0;
1012
1013 out_free:
1014         kfree(slwt->srh);
1015         kfree(newts);
1016         return err;
1017 }
1018
1019 static void seg6_local_destroy_state(struct lwtunnel_state *lwt)
1020 {
1021         struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
1022
1023         kfree(slwt->srh);
1024
1025         if (slwt->desc->attrs & (1 << SEG6_LOCAL_BPF)) {
1026                 kfree(slwt->bpf.name);
1027                 bpf_prog_put(slwt->bpf.prog);
1028         }
1029
1030         return;
1031 }
1032
1033 static int seg6_local_fill_encap(struct sk_buff *skb,
1034                                  struct lwtunnel_state *lwt)
1035 {
1036         struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
1037         struct seg6_action_param *param;
1038         int i, err;
1039
1040         if (nla_put_u32(skb, SEG6_LOCAL_ACTION, slwt->action))
1041                 return -EMSGSIZE;
1042
1043         for (i = 0; i < SEG6_LOCAL_MAX + 1; i++) {
1044                 if (slwt->desc->attrs & (1 << i)) {
1045                         param = &seg6_action_params[i];
1046                         err = param->put(skb, slwt);
1047                         if (err < 0)
1048                                 return err;
1049                 }
1050         }
1051
1052         return 0;
1053 }
1054
1055 static int seg6_local_get_encap_size(struct lwtunnel_state *lwt)
1056 {
1057         struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
1058         unsigned long attrs;
1059         int nlsize;
1060
1061         nlsize = nla_total_size(4); /* action */
1062
1063         attrs = slwt->desc->attrs;
1064
1065         if (attrs & (1 << SEG6_LOCAL_SRH))
1066                 nlsize += nla_total_size((slwt->srh->hdrlen + 1) << 3);
1067
1068         if (attrs & (1 << SEG6_LOCAL_TABLE))
1069                 nlsize += nla_total_size(4);
1070
1071         if (attrs & (1 << SEG6_LOCAL_NH4))
1072                 nlsize += nla_total_size(4);
1073
1074         if (attrs & (1 << SEG6_LOCAL_NH6))
1075                 nlsize += nla_total_size(16);
1076
1077         if (attrs & (1 << SEG6_LOCAL_IIF))
1078                 nlsize += nla_total_size(4);
1079
1080         if (attrs & (1 << SEG6_LOCAL_OIF))
1081                 nlsize += nla_total_size(4);
1082
1083         if (attrs & (1 << SEG6_LOCAL_BPF))
1084                 nlsize += nla_total_size(sizeof(struct nlattr)) +
1085                        nla_total_size(MAX_PROG_NAME) +
1086                        nla_total_size(4);
1087
1088         return nlsize;
1089 }
1090
1091 static int seg6_local_cmp_encap(struct lwtunnel_state *a,
1092                                 struct lwtunnel_state *b)
1093 {
1094         struct seg6_local_lwt *slwt_a, *slwt_b;
1095         struct seg6_action_param *param;
1096         int i;
1097
1098         slwt_a = seg6_local_lwtunnel(a);
1099         slwt_b = seg6_local_lwtunnel(b);
1100
1101         if (slwt_a->action != slwt_b->action)
1102                 return 1;
1103
1104         if (slwt_a->desc->attrs != slwt_b->desc->attrs)
1105                 return 1;
1106
1107         for (i = 0; i < SEG6_LOCAL_MAX + 1; i++) {
1108                 if (slwt_a->desc->attrs & (1 << i)) {
1109                         param = &seg6_action_params[i];
1110                         if (param->cmp(slwt_a, slwt_b))
1111                                 return 1;
1112                 }
1113         }
1114
1115         return 0;
1116 }
1117
1118 static const struct lwtunnel_encap_ops seg6_local_ops = {
1119         .build_state    = seg6_local_build_state,
1120         .destroy_state  = seg6_local_destroy_state,
1121         .input          = seg6_local_input,
1122         .fill_encap     = seg6_local_fill_encap,
1123         .get_encap_size = seg6_local_get_encap_size,
1124         .cmp_encap      = seg6_local_cmp_encap,
1125         .owner          = THIS_MODULE,
1126 };
1127
1128 int __init seg6_local_init(void)
1129 {
1130         return lwtunnel_encap_add_ops(&seg6_local_ops,
1131                                       LWTUNNEL_ENCAP_SEG6_LOCAL);
1132 }
1133
1134 void seg6_local_exit(void)
1135 {
1136         lwtunnel_encap_del_ops(&seg6_local_ops, LWTUNNEL_ENCAP_SEG6_LOCAL);
1137 }