net/ipv6/seg6_iptunnel.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  SR-IPv6 implementation
   4  *
   5  *  Author:
   6  *  David Lebrun <david.lebrun@uclouvain.be>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/net.h>
  12 #include <linux/module.h>
  13 #include <net/ip.h>
  14 #include <net/ip_tunnels.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_iptunnel.h>
  23 #include <net/addrconf.h>
  24 #include <net/ip6_route.h>
  25 #include <net/dst_cache.h>
  26 #ifdef CONFIG_IPV6_SEG6_HMAC
  27 #include <net/seg6_hmac.h>
  28 #endif
  29 #include <linux/netfilter.h>
  30
  31 static size_t seg6_lwt_headroom(struct seg6_iptunnel_encap *tuninfo)
  32 {
  33         int head = 0;
  34
  35         switch (tuninfo->mode) {
  36         case SEG6_IPTUN_MODE_INLINE:
  37                 break;
  38         case SEG6_IPTUN_MODE_ENCAP:
  39         case SEG6_IPTUN_MODE_ENCAP_RED:
  40                 head = sizeof(struct ipv6hdr);
  41                 break;
  42         case SEG6_IPTUN_MODE_L2ENCAP:
  43         case SEG6_IPTUN_MODE_L2ENCAP_RED:
  44                 return 0;
  45         }
  46
  47         return ((tuninfo->srh->hdrlen + 1) << 3) + head;
  48 }
  49
  50 struct seg6_lwt {
  51         struct dst_cache cache;
  52         struct seg6_iptunnel_encap tuninfo[];
  53 };
  54
  55 static inline struct seg6_lwt *seg6_lwt_lwtunnel(struct lwtunnel_state *lwt)
  56 {
  57         return (struct seg6_lwt *)lwt->data;
  58 }
  59
  60 static inline struct seg6_iptunnel_encap *
  61 seg6_encap_lwtunnel(struct lwtunnel_state *lwt)
  62 {
  63         return seg6_lwt_lwtunnel(lwt)->tuninfo;
  64 }
  65
  66 static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = {
  67         [SEG6_IPTUNNEL_SRH]     = { .type = NLA_BINARY },
  68 };
  69
  70 static int nla_put_srh(struct sk_buff *skb, int attrtype,
  71                        struct seg6_iptunnel_encap *tuninfo)
  72 {
  73         struct seg6_iptunnel_encap *data;
  74         struct nlattr *nla;
  75         int len;
  76
  77         len = SEG6_IPTUN_ENCAP_SIZE(tuninfo);
  78
  79         nla = nla_reserve(skb, attrtype, len);
  80         if (!nla)
  81                 return -EMSGSIZE;
  82
  83         data = nla_data(nla);
  84         memcpy(data, tuninfo, len);
  85
  86         return 0;
  87 }
  88
  89 static void set_tun_src(struct net *net, struct net_device *dev,
  90                         struct in6_addr *daddr, struct in6_addr *saddr)
  91 {
  92         struct seg6_pernet_data *sdata = seg6_pernet(net);
  93         struct in6_addr *tun_src;
  94
  95         rcu_read_lock();
  96
  97         tun_src = rcu_dereference(sdata->tun_src);
  98
  99         if (!ipv6_addr_any(tun_src)) {
 100                 memcpy(saddr, tun_src, sizeof(struct in6_addr));
 101         } else {
 102                 ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC,
 103                                    saddr);
 104         }
 105
 106         rcu_read_unlock();
 107 }
 108
 109 /* Compute flowlabel for outer IPv6 header */
 110 static __be32 seg6_make_flowlabel(struct net *net, struct sk_buff *skb,
 111                                   struct ipv6hdr *inner_hdr)
 112 {
 113         int do_flowlabel = net->ipv6.sysctl.seg6_flowlabel;
 114         __be32 flowlabel = 0;
 115         u32 hash;
 116
 117         if (do_flowlabel > 0) {
 118                 hash = skb_get_hash(skb);
 119                 hash = rol32(hash, 16);
 120                 flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
 121         } else if (!do_flowlabel && skb->protocol == htons(ETH_P_IPV6)) {
 122                 flowlabel = ip6_flowlabel(inner_hdr);
 123         }
 124         return flowlabel;
 125 }
 126
 127 /* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
 128 int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
 129 {
 130         struct dst_entry *dst = skb_dst(skb);
 131         struct net *net = dev_net(dst->dev);
 132         struct ipv6hdr *hdr, *inner_hdr;
 133         struct ipv6_sr_hdr *isrh;
 134         int hdrlen, tot_len, err;
 135         __be32 flowlabel;
 136
 137         hdrlen = (osrh->hdrlen + 1) << 3;
 138         tot_len = hdrlen + sizeof(*hdr);
 139
 140         err = skb_cow_head(skb, tot_len + skb->mac_len);
 141         if (unlikely(err))
 142                 return err;
 143
 144         inner_hdr = ipv6_hdr(skb);
 145         flowlabel = seg6_make_flowlabel(net, skb, inner_hdr);
 146
 147         skb_push(skb, tot_len);
 148         skb_reset_network_header(skb);
 149         skb_mac_header_rebuild(skb);
 150         hdr = ipv6_hdr(skb);
 151
 152         /* inherit tc, flowlabel and hlim
 153          * hlim will be decremented in ip6_forward() afterwards and
 154          * decapsulation will overwrite inner hlim with outer hlim
 155          */
 156
 157         if (skb->protocol == htons(ETH_P_IPV6)) {
 158                 ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
 159                              flowlabel);
 160                 hdr->hop_limit = inner_hdr->hop_limit;
 161         } else {
 162                 ip6_flow_hdr(hdr, 0, flowlabel);
 163                 hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
 164
 165                 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 166
 167                 /* the control block has been erased, so we have to set the
 168                  * iif once again.
 169                  * We read the receiving interface index directly from the
 170                  * skb->skb_iif as it is done in the IPv4 receiving path (i.e.:
 171                  * ip_rcv_core(...)).
 172                  */
 173                 IP6CB(skb)->iif = skb->skb_iif;
 174         }
 175
 176         hdr->nexthdr = NEXTHDR_ROUTING;
 177
 178         isrh = (void *)hdr + sizeof(*hdr);
 179         memcpy(isrh, osrh, hdrlen);
 180
 181         isrh->nexthdr = proto;
 182
 183         hdr->daddr = isrh->segments[isrh->first_segment];
 184         set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
 185
 186 #ifdef CONFIG_IPV6_SEG6_HMAC
 187         if (sr_has_hmac(isrh)) {
 188                 err = seg6_push_hmac(net, &hdr->saddr, isrh);
 189                 if (unlikely(err))
 190                         return err;
 191         }
 192 #endif
 193
 194         hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 195
 196         skb_postpush_rcsum(skb, hdr, tot_len);
 197
 198         return 0;
 199 }
 200 EXPORT_SYMBOL_GPL(seg6_do_srh_encap);
 201
 202 /* encapsulate an IPv6 packet within an outer IPv6 header with reduced SRH */
 203 static int seg6_do_srh_encap_red(struct sk_buff *skb,
 204                                  struct ipv6_sr_hdr *osrh, int proto)
 205 {
 206         __u8 first_seg = osrh->first_segment;
 207         struct dst_entry *dst = skb_dst(skb);
 208         struct net *net = dev_net(dst->dev);
 209         struct ipv6hdr *hdr, *inner_hdr;
 210         int hdrlen = ipv6_optlen(osrh);
 211         int red_tlv_offset, tlv_offset;
 212         struct ipv6_sr_hdr *isrh;
 213         bool skip_srh = false;
 214         __be32 flowlabel;
 215         int tot_len, err;
 216         int red_hdrlen;
 217         int tlvs_len;
 218
 219         if (first_seg > 0) {
 220                 red_hdrlen = hdrlen - sizeof(struct in6_addr);
 221         } else {
 222                 /* NOTE: if tag/flags and/or other TLVs are introduced in the
 223                  * seg6_iptunnel infrastructure, they should be considered when
 224                  * deciding to skip the SRH.
 225                  */
 226                 skip_srh = !sr_has_hmac(osrh);
 227
 228                 red_hdrlen = skip_srh ? 0 : hdrlen;
 229         }
 230
 231         tot_len = red_hdrlen + sizeof(struct ipv6hdr);
 232
 233         err = skb_cow_head(skb, tot_len + skb->mac_len);
 234         if (unlikely(err))
 235                 return err;
 236
 237         inner_hdr = ipv6_hdr(skb);
 238         flowlabel = seg6_make_flowlabel(net, skb, inner_hdr);
 239
 240         skb_push(skb, tot_len);
 241         skb_reset_network_header(skb);
 242         skb_mac_header_rebuild(skb);
 243         hdr = ipv6_hdr(skb);
 244
 245         /* based on seg6_do_srh_encap() */
 246         if (skb->protocol == htons(ETH_P_IPV6)) {
 247                 ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
 248                              flowlabel);
 249                 hdr->hop_limit = inner_hdr->hop_limit;
 250         } else {
 251                 ip6_flow_hdr(hdr, 0, flowlabel);
 252                 hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
 253
 254                 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 255                 IP6CB(skb)->iif = skb->skb_iif;
 256         }
 257
 258         /* no matter if we have to skip the SRH or not, the first segment
 259          * always comes in the pushed IPv6 header.
 260          */
 261         hdr->daddr = osrh->segments[first_seg];
 262
 263         if (skip_srh) {
 264                 hdr->nexthdr = proto;
 265
 266                 set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
 267                 goto out;
 268         }
 269
 270         /* we cannot skip the SRH, slow path */
 271
 272         hdr->nexthdr = NEXTHDR_ROUTING;
 273         isrh = (void *)hdr + sizeof(struct ipv6hdr);
 274
 275         if (unlikely(!first_seg)) {
 276                 /* this is a very rare case; we have only one SID but
 277                  * we cannot skip the SRH since we are carrying some
 278                  * other info.
 279                  */
 280                 memcpy(isrh, osrh, hdrlen);
 281                 goto srcaddr;
 282         }
 283
 284         tlv_offset = sizeof(*osrh) + (first_seg + 1) * sizeof(struct in6_addr);
 285         red_tlv_offset = tlv_offset - sizeof(struct in6_addr);
 286
 287         memcpy(isrh, osrh, red_tlv_offset);
 288
 289         tlvs_len = hdrlen - tlv_offset;
 290         if (unlikely(tlvs_len > 0)) {
 291                 const void *s = (const void *)osrh + tlv_offset;
 292                 void *d = (void *)isrh + red_tlv_offset;
 293
 294                 memcpy(d, s, tlvs_len);
 295         }
 296
 297         --isrh->first_segment;
 298         isrh->hdrlen -= 2;
 299
 300 srcaddr:
 301         isrh->nexthdr = proto;
 302         set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
 303
 304 #ifdef CONFIG_IPV6_SEG6_HMAC
 305         if (unlikely(!skip_srh && sr_has_hmac(isrh))) {
 306                 err = seg6_push_hmac(net, &hdr->saddr, isrh);
 307                 if (unlikely(err))
 308                         return err;
 309         }
 310 #endif
 311
 312 out:
 313         hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 314
 315         skb_postpush_rcsum(skb, hdr, tot_len);
 316
 317         return 0;
 318 }
 319
 320 /* insert an SRH within an IPv6 packet, just after the IPv6 header */
 321 int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
 322 {
 323         struct ipv6hdr *hdr, *oldhdr;
 324         struct ipv6_sr_hdr *isrh;
 325         int hdrlen, err;
 326
 327         hdrlen = (osrh->hdrlen + 1) << 3;
 328
 329         err = skb_cow_head(skb, hdrlen + skb->mac_len);
 330         if (unlikely(err))
 331                 return err;
 332
 333         oldhdr = ipv6_hdr(skb);
 334
 335         skb_pull(skb, sizeof(struct ipv6hdr));
 336         skb_postpull_rcsum(skb, skb_network_header(skb),
 337                            sizeof(struct ipv6hdr));
 338
 339         skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
 340         skb_reset_network_header(skb);
 341         skb_mac_header_rebuild(skb);
 342
 343         hdr = ipv6_hdr(skb);
 344
 345         memmove(hdr, oldhdr, sizeof(*hdr));
 346
 347         isrh = (void *)hdr + sizeof(*hdr);
 348         memcpy(isrh, osrh, hdrlen);
 349
 350         isrh->nexthdr = hdr->nexthdr;
 351         hdr->nexthdr = NEXTHDR_ROUTING;
 352
 353         isrh->segments[0] = hdr->daddr;
 354         hdr->daddr = isrh->segments[isrh->first_segment];
 355
 356 #ifdef CONFIG_IPV6_SEG6_HMAC
 357         if (sr_has_hmac(isrh)) {
 358                 struct net *net = dev_net(skb_dst(skb)->dev);
 359
 360                 err = seg6_push_hmac(net, &hdr->saddr, isrh);
 361                 if (unlikely(err))
 362                         return err;
 363         }
 364 #endif
 365
 366         hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 367
 368         skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
 369
 370         return 0;
 371 }
 372 EXPORT_SYMBOL_GPL(seg6_do_srh_inline);
 373
 374 static int seg6_do_srh(struct sk_buff *skb)
 375 {
 376         struct dst_entry *dst = skb_dst(skb);
 377         struct seg6_iptunnel_encap *tinfo;
 378         int proto, err = 0;
 379
 380         tinfo = seg6_encap_lwtunnel(dst->lwtstate);
 381
 382         switch (tinfo->mode) {
 383         case SEG6_IPTUN_MODE_INLINE:
 384                 if (skb->protocol != htons(ETH_P_IPV6))
 385                         return -EINVAL;
 386
 387                 err = seg6_do_srh_inline(skb, tinfo->srh);
 388                 if (err)
 389                         return err;
 390                 break;
 391         case SEG6_IPTUN_MODE_ENCAP:
 392         case SEG6_IPTUN_MODE_ENCAP_RED:
 393                 err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
 394                 if (err)
 395                         return err;
 396
 397                 if (skb->protocol == htons(ETH_P_IPV6))
 398                         proto = IPPROTO_IPV6;
 399                 else if (skb->protocol == htons(ETH_P_IP))
 400                         proto = IPPROTO_IPIP;
 401                 else
 402                         return -EINVAL;
 403
 404                 if (tinfo->mode == SEG6_IPTUN_MODE_ENCAP)
 405                         err = seg6_do_srh_encap(skb, tinfo->srh, proto);
 406                 else
 407                         err = seg6_do_srh_encap_red(skb, tinfo->srh, proto);
 408
 409                 if (err)
 410                         return err;
 411
 412                 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
 413                 skb_set_inner_protocol(skb, skb->protocol);
 414                 skb->protocol = htons(ETH_P_IPV6);
 415                 break;
 416         case SEG6_IPTUN_MODE_L2ENCAP:
 417         case SEG6_IPTUN_MODE_L2ENCAP_RED:
 418                 if (!skb_mac_header_was_set(skb))
 419                         return -EINVAL;
 420
 421                 if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0)
 422                         return -ENOMEM;
 423
 424                 skb_mac_header_rebuild(skb);
 425                 skb_push(skb, skb->mac_len);
 426
 427                 if (tinfo->mode == SEG6_IPTUN_MODE_L2ENCAP)
 428                         err = seg6_do_srh_encap(skb, tinfo->srh,
 429                                                 IPPROTO_ETHERNET);
 430                 else
 431                         err = seg6_do_srh_encap_red(skb, tinfo->srh,
 432                                                     IPPROTO_ETHERNET);
 433
 434                 if (err)
 435                         return err;
 436
 437                 skb->protocol = htons(ETH_P_IPV6);
 438                 break;
 439         }
 440
 441         skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 442         nf_reset_ct(skb);
 443
 444         return 0;
 445 }
 446
 447 static int seg6_input_finish(struct net *net, struct sock *sk,
 448                              struct sk_buff *skb)
 449 {
 450         return dst_input(skb);
 451 }
 452
 453 static int seg6_input_core(struct net *net, struct sock *sk,
 454                            struct sk_buff *skb)
 455 {
 456         struct dst_entry *orig_dst = skb_dst(skb);
 457         struct dst_entry *dst = NULL;
 458         struct seg6_lwt *slwt;
 459         int err;
 460
 461         err = seg6_do_srh(skb);
 462         if (unlikely(err))
 463                 goto drop;
 464
 465         slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
 466
 467         local_bh_disable();
 468         dst = dst_cache_get(&slwt->cache);
 469
 470         if (!dst) {
 471                 ip6_route_input(skb);
 472                 dst = skb_dst(skb);
 473                 if (!dst->error) {
 474                         dst_cache_set_ip6(&slwt->cache, dst,
 475                                           &ipv6_hdr(skb)->saddr);
 476                 }
 477         } else {
 478                 skb_dst_drop(skb);
 479                 skb_dst_set(skb, dst);
 480         }
 481         local_bh_enable();
 482
 483         err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
 484         if (unlikely(err))
 485                 goto drop;
 486
 487         if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
 488                 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
 489                                dev_net(skb->dev), NULL, skb, NULL,
 490                                skb_dst(skb)->dev, seg6_input_finish);
 491
 492         return seg6_input_finish(dev_net(skb->dev), NULL, skb);
 493 drop:
 494         kfree_skb(skb);
 495         return err;
 496 }
 497
 498 static int seg6_input_nf(struct sk_buff *skb)
 499 {
 500         struct net_device *dev = skb_dst(skb)->dev;
 501         struct net *net = dev_net(skb->dev);
 502
 503         switch (skb->protocol) {
 504         case htons(ETH_P_IP):
 505                 return NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, net, NULL,
 506                                skb, NULL, dev, seg6_input_core);
 507         case htons(ETH_P_IPV6):
 508                 return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, net, NULL,
 509                                skb, NULL, dev, seg6_input_core);
 510         }
 511
 512         return -EINVAL;
 513 }
 514
 515 static int seg6_input(struct sk_buff *skb)
 516 {
 517         if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
 518                 return seg6_input_nf(skb);
 519
 520         return seg6_input_core(dev_net(skb->dev), NULL, skb);
 521 }
 522
 523 static int seg6_output_core(struct net *net, struct sock *sk,
 524                             struct sk_buff *skb)
 525 {
 526         struct dst_entry *orig_dst = skb_dst(skb);
 527         struct dst_entry *dst = NULL;
 528         struct seg6_lwt *slwt;
 529         int err;
 530
 531         err = seg6_do_srh(skb);
 532         if (unlikely(err))
 533                 goto drop;
 534
 535         slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
 536
 537         local_bh_disable();
 538         dst = dst_cache_get(&slwt->cache);
 539         local_bh_enable();
 540
 541         if (unlikely(!dst)) {
 542                 struct ipv6hdr *hdr = ipv6_hdr(skb);
 543                 struct flowi6 fl6;
 544
 545                 memset(&fl6, 0, sizeof(fl6));
 546                 fl6.daddr = hdr->daddr;
 547                 fl6.saddr = hdr->saddr;
 548                 fl6.flowlabel = ip6_flowinfo(hdr);
 549                 fl6.flowi6_mark = skb->mark;
 550                 fl6.flowi6_proto = hdr->nexthdr;
 551
 552                 dst = ip6_route_output(net, NULL, &fl6);
 553                 if (dst->error) {
 554                         err = dst->error;
 555                         dst_release(dst);
 556                         goto drop;
 557                 }
 558
 559                 local_bh_disable();
 560                 dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
 561                 local_bh_enable();
 562         }
 563
 564         skb_dst_drop(skb);
 565         skb_dst_set(skb, dst);
 566
 567         err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
 568         if (unlikely(err))
 569                 goto drop;
 570
 571         if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
 572                 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net, sk, skb,
 573                                NULL, skb_dst(skb)->dev, dst_output);
 574
 575         return dst_output(net, sk, skb);
 576 drop:
 577         kfree_skb(skb);
 578         return err;
 579 }
 580
 581 static int seg6_output_nf(struct net *net, struct sock *sk, struct sk_buff *skb)
 582 {
 583         struct net_device *dev = skb_dst(skb)->dev;
 584
 585         switch (skb->protocol) {
 586         case htons(ETH_P_IP):
 587                 return NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, net, sk, skb,
 588                                NULL, dev, seg6_output_core);
 589         case htons(ETH_P_IPV6):
 590                 return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, net, sk, skb,
 591                                NULL, dev, seg6_output_core);
 592         }
 593
 594         return -EINVAL;
 595 }
 596
 597 static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 598 {
 599         if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
 600                 return seg6_output_nf(net, sk, skb);
 601
 602         return seg6_output_core(net, sk, skb);
 603 }
 604
 605 static int seg6_build_state(struct net *net, struct nlattr *nla,
 606                             unsigned int family, const void *cfg,
 607                             struct lwtunnel_state **ts,
 608                             struct netlink_ext_ack *extack)
 609 {
 610         struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
 611         struct seg6_iptunnel_encap *tuninfo;
 612         struct lwtunnel_state *newts;
 613         int tuninfo_len, min_size;
 614         struct seg6_lwt *slwt;
 615         int err;
 616
 617         if (family != AF_INET && family != AF_INET6)
 618                 return -EINVAL;
 619
 620         err = nla_parse_nested_deprecated(tb, SEG6_IPTUNNEL_MAX, nla,
 621                                           seg6_iptunnel_policy, extack);
 622
 623         if (err < 0)
 624                 return err;
 625
 626         if (!tb[SEG6_IPTUNNEL_SRH])
 627                 return -EINVAL;
 628
 629         tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
 630         tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);
 631
 632         /* tuninfo must contain at least the iptunnel encap structure,
 633          * the SRH and one segment
 634          */
 635         min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
 636                    sizeof(struct in6_addr);
 637         if (tuninfo_len < min_size)
 638                 return -EINVAL;
 639
 640         switch (tuninfo->mode) {
 641         case SEG6_IPTUN_MODE_INLINE:
 642                 if (family != AF_INET6)
 643                         return -EINVAL;
 644
 645                 break;
 646         case SEG6_IPTUN_MODE_ENCAP:
 647                 break;
 648         case SEG6_IPTUN_MODE_L2ENCAP:
 649                 break;
 650         case SEG6_IPTUN_MODE_ENCAP_RED:
 651                 break;
 652         case SEG6_IPTUN_MODE_L2ENCAP_RED:
 653                 break;
 654         default:
 655                 return -EINVAL;
 656         }
 657
 658         /* verify that SRH is consistent */
 659         if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo), false))
 660                 return -EINVAL;
 661
 662         newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
 663         if (!newts)
 664                 return -ENOMEM;
 665
 666         slwt = seg6_lwt_lwtunnel(newts);
 667
 668         err = dst_cache_init(&slwt->cache, GFP_ATOMIC);
 669         if (err) {
 670                 kfree(newts);
 671                 return err;
 672         }
 673
 674         memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);
 675
 676         newts->type = LWTUNNEL_ENCAP_SEG6;
 677         newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
 678
 679         if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP)
 680                 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
 681
 682         newts->headroom = seg6_lwt_headroom(tuninfo);
 683
 684         *ts = newts;
 685
 686         return 0;
 687 }
 688
 689 static void seg6_destroy_state(struct lwtunnel_state *lwt)
 690 {
 691         dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
 692 }
 693
 694 static int seg6_fill_encap_info(struct sk_buff *skb,
 695                                 struct lwtunnel_state *lwtstate)
 696 {
 697         struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
 698
 699         if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
 700                 return -EMSGSIZE;
 701
 702         return 0;
 703 }
 704
 705 static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
 706 {
 707         struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
 708
 709         return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
 710 }
 711
 712 static int seg6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
 713 {
 714         struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
 715         struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
 716         int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);
 717
 718         if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
 719                 return 1;
 720
 721         return memcmp(a_hdr, b_hdr, len);
 722 }
 723
 724 static const struct lwtunnel_encap_ops seg6_iptun_ops = {
 725         .build_state = seg6_build_state,
 726         .destroy_state = seg6_destroy_state,
 727         .output = seg6_output,
 728         .input = seg6_input,
 729         .fill_encap = seg6_fill_encap_info,
 730         .get_encap_size = seg6_encap_nlsize,
 731         .cmp_encap = seg6_encap_cmp,
 732         .owner = THIS_MODULE,
 733 };
 734
 735 int __init seg6_iptunnel_init(void)
 736 {
 737         return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
 738 }
 739
 740 void seg6_iptunnel_exit(void)
 741 {
 742         lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
 743 }