net/ipv4/ip_tunnel_core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2013 Nicira, Inc.
   4  */
   5
   6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   7
   8 #include <linux/types.h>
   9 #include <linux/kernel.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/netdevice.h>
  12 #include <linux/in.h>
  13 #include <linux/if_arp.h>
  14 #include <linux/init.h>
  15 #include <linux/in6.h>
  16 #include <linux/inetdevice.h>
  17 #include <linux/netfilter_ipv4.h>
  18 #include <linux/etherdevice.h>
  19 #include <linux/if_ether.h>
  20 #include <linux/if_vlan.h>
  21 #include <linux/static_key.h>
  22
  23 #include <net/ip.h>
  24 #include <net/icmp.h>
  25 #include <net/protocol.h>
  26 #include <net/ip_tunnels.h>
  27 #include <net/ip6_tunnel.h>
  28 #include <net/ip6_checksum.h>
  29 #include <net/arp.h>
  30 #include <net/checksum.h>
  31 #include <net/dsfield.h>
  32 #include <net/inet_ecn.h>
  33 #include <net/xfrm.h>
  34 #include <net/net_namespace.h>
  35 #include <net/netns/generic.h>
  36 #include <net/rtnetlink.h>
  37 #include <net/dst_metadata.h>
  38 #include <net/geneve.h>
  39 #include <net/vxlan.h>
  40 #include <net/erspan.h>
  41
  42 const struct ip_tunnel_encap_ops __rcu *
  43                 iptun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
  44 EXPORT_SYMBOL(iptun_encaps);
  45
  46 const struct ip6_tnl_encap_ops __rcu *
  47                 ip6tun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
  48 EXPORT_SYMBOL(ip6tun_encaps);
  49
  50 void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
  51                    __be32 src, __be32 dst, __u8 proto,
  52                    __u8 tos, __u8 ttl, __be16 df, bool xnet)
  53 {
  54         int pkt_len = skb->len - skb_inner_network_offset(skb);
  55         struct net *net = dev_net(rt->dst.dev);
  56         struct net_device *dev = skb->dev;
  57         struct iphdr *iph;
  58         int err;
  59
  60         skb_scrub_packet(skb, xnet);
  61
  62         skb_clear_hash_if_not_l4(skb);
  63         skb_dst_set(skb, &rt->dst);
  64         memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
  65
  66         /* Push down and install the IP header. */
  67         skb_push(skb, sizeof(struct iphdr));
  68         skb_reset_network_header(skb);
  69
  70         iph = ip_hdr(skb);
  71
  72         iph->version    =       4;
  73         iph->ihl        =       sizeof(struct iphdr) >> 2;
  74         iph->frag_off   =       ip_mtu_locked(&rt->dst) ? 0 : df;
  75         iph->protocol   =       proto;
  76         iph->tos        =       tos;
  77         iph->daddr      =       dst;
  78         iph->saddr      =       src;
  79         iph->ttl        =       ttl;
  80         __ip_select_ident(net, iph, skb_shinfo(skb)->gso_segs ?: 1);
  81
  82         err = ip_local_out(net, sk, skb);
  83
  84         if (dev) {
  85                 if (unlikely(net_xmit_eval(err)))
  86                         pkt_len = 0;
  87                 iptunnel_xmit_stats(dev, pkt_len);
  88         }
  89 }
  90 EXPORT_SYMBOL_GPL(iptunnel_xmit);
  91
  92 int __iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
  93                            __be16 inner_proto, bool raw_proto, bool xnet)
  94 {
  95         if (unlikely(!pskb_may_pull(skb, hdr_len)))
  96                 return -ENOMEM;
  97
  98         skb_pull_rcsum(skb, hdr_len);
  99
 100         if (!raw_proto && inner_proto == htons(ETH_P_TEB)) {
 101                 struct ethhdr *eh;
 102
 103                 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
 104                         return -ENOMEM;
 105
 106                 eh = (struct ethhdr *)skb->data;
 107                 if (likely(eth_proto_is_802_3(eh->h_proto)))
 108                         skb->protocol = eh->h_proto;
 109                 else
 110                         skb->protocol = htons(ETH_P_802_2);
 111
 112         } else {
 113                 skb->protocol = inner_proto;
 114         }
 115
 116         skb_clear_hash_if_not_l4(skb);
 117         __vlan_hwaccel_clear_tag(skb);
 118         skb_set_queue_mapping(skb, 0);
 119         skb_scrub_packet(skb, xnet);
 120
 121         return iptunnel_pull_offloads(skb);
 122 }
 123 EXPORT_SYMBOL_GPL(__iptunnel_pull_header);
 124
 125 struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
 126                                              gfp_t flags)
 127 {
 128         struct metadata_dst *res;
 129         struct ip_tunnel_info *dst, *src;
 130
 131         if (!md || md->type != METADATA_IP_TUNNEL ||
 132             md->u.tun_info.mode & IP_TUNNEL_INFO_TX)
 133                 return NULL;
 134
 135         src = &md->u.tun_info;
 136         res = metadata_dst_alloc(src->options_len, METADATA_IP_TUNNEL, flags);
 137         if (!res)
 138                 return NULL;
 139
 140         dst = &res->u.tun_info;
 141         dst->key.tun_id = src->key.tun_id;
 142         if (src->mode & IP_TUNNEL_INFO_IPV6)
 143                 memcpy(&dst->key.u.ipv6.dst, &src->key.u.ipv6.src,
 144                        sizeof(struct in6_addr));
 145         else
 146                 dst->key.u.ipv4.dst = src->key.u.ipv4.src;
 147         dst->key.tun_flags = src->key.tun_flags;
 148         dst->mode = src->mode | IP_TUNNEL_INFO_TX;
 149         ip_tunnel_info_opts_set(dst, ip_tunnel_info_opts(src),
 150                                 src->options_len, 0);
 151
 152         return res;
 153 }
 154 EXPORT_SYMBOL_GPL(iptunnel_metadata_reply);
 155
 156 int iptunnel_handle_offloads(struct sk_buff *skb,
 157                              int gso_type_mask)
 158 {
 159         int err;
 160
 161         if (likely(!skb->encapsulation)) {
 162                 skb_reset_inner_headers(skb);
 163                 skb->encapsulation = 1;
 164         }
 165
 166         if (skb_is_gso(skb)) {
 167                 err = skb_header_unclone(skb, GFP_ATOMIC);
 168                 if (unlikely(err))
 169                         return err;
 170                 skb_shinfo(skb)->gso_type |= gso_type_mask;
 171                 return 0;
 172         }
 173
 174         if (skb->ip_summed != CHECKSUM_PARTIAL) {
 175                 skb->ip_summed = CHECKSUM_NONE;
 176                 /* We clear encapsulation here to prevent badly-written
 177                  * drivers potentially deciding to offload an inner checksum
 178                  * if we set CHECKSUM_PARTIAL on the outer header.
 179                  * This should go away when the drivers are all fixed.
 180                  */
 181                 skb->encapsulation = 0;
 182         }
 183
 184         return 0;
 185 }
 186 EXPORT_SYMBOL_GPL(iptunnel_handle_offloads);
 187
 188 /**
 189  * iptunnel_pmtud_build_icmp() - Build ICMP error message for PMTUD
 190  * @skb:        Original packet with L2 header
 191  * @mtu:        MTU value for ICMP error
 192  *
 193  * Return: length on success, negative error code if message couldn't be built.
 194  */
 195 static int iptunnel_pmtud_build_icmp(struct sk_buff *skb, int mtu)
 196 {
 197         const struct iphdr *iph = ip_hdr(skb);
 198         struct icmphdr *icmph;
 199         struct iphdr *niph;
 200         struct ethhdr eh;
 201         int len, err;
 202
 203         if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct iphdr)))
 204                 return -EINVAL;
 205
 206         skb_copy_bits(skb, skb_mac_offset(skb), &eh, ETH_HLEN);
 207         pskb_pull(skb, ETH_HLEN);
 208         skb_reset_network_header(skb);
 209
 210         err = pskb_trim(skb, 576 - sizeof(*niph) - sizeof(*icmph));
 211         if (err)
 212                 return err;
 213
 214         len = skb->len + sizeof(*icmph);
 215         err = skb_cow(skb, sizeof(*niph) + sizeof(*icmph) + ETH_HLEN);
 216         if (err)
 217                 return err;
 218
 219         icmph = skb_push(skb, sizeof(*icmph));
 220         *icmph = (struct icmphdr) {
 221                 .type                   = ICMP_DEST_UNREACH,
 222                 .code                   = ICMP_FRAG_NEEDED,
 223                 .checksum               = 0,
 224                 .un.frag.__unused       = 0,
 225                 .un.frag.mtu            = ntohs(mtu),
 226         };
 227         icmph->checksum = ip_compute_csum(icmph, len);
 228         skb_reset_transport_header(skb);
 229
 230         niph = skb_push(skb, sizeof(*niph));
 231         *niph = (struct iphdr) {
 232                 .ihl                    = sizeof(*niph) / 4u,
 233                 .version                = 4,
 234                 .tos                    = 0,
 235                 .tot_len                = htons(len + sizeof(*niph)),
 236                 .id                     = 0,
 237                 .frag_off               = htons(IP_DF),
 238                 .ttl                    = iph->ttl,
 239                 .protocol               = IPPROTO_ICMP,
 240                 .saddr                  = iph->daddr,
 241                 .daddr                  = iph->saddr,
 242         };
 243         ip_send_check(niph);
 244         skb_reset_network_header(skb);
 245
 246         skb->ip_summed = CHECKSUM_NONE;
 247
 248         eth_header(skb, skb->dev, htons(eh.h_proto), eh.h_source, eh.h_dest, 0);
 249         skb_reset_mac_header(skb);
 250
 251         return skb->len;
 252 }
 253
 254 /**
 255  * iptunnel_pmtud_check_icmp() - Trigger ICMP reply if needed and allowed
 256  * @skb:        Buffer being sent by encapsulation, L2 headers expected
 257  * @mtu:        Network MTU for path
 258  *
 259  * Return: 0 for no ICMP reply, length if built, negative value on error.
 260  */
 261 static int iptunnel_pmtud_check_icmp(struct sk_buff *skb, int mtu)
 262 {
 263         const struct icmphdr *icmph = icmp_hdr(skb);
 264         const struct iphdr *iph = ip_hdr(skb);
 265
 266         if (mtu < 576 || iph->frag_off != htons(IP_DF))
 267                 return 0;
 268
 269         if (ipv4_is_lbcast(iph->daddr)  || ipv4_is_multicast(iph->daddr) ||
 270             ipv4_is_zeronet(iph->saddr) || ipv4_is_loopback(iph->saddr)  ||
 271             ipv4_is_lbcast(iph->saddr)  || ipv4_is_multicast(iph->saddr))
 272                 return 0;
 273
 274         if (iph->protocol == IPPROTO_ICMP && icmp_is_err(icmph->type))
 275                 return 0;
 276
 277         return iptunnel_pmtud_build_icmp(skb, mtu);
 278 }
 279
 280 #if IS_ENABLED(CONFIG_IPV6)
 281 /**
 282  * iptunnel_pmtud_build_icmpv6() - Build ICMPv6 error message for PMTUD
 283  * @skb:        Original packet with L2 header
 284  * @mtu:        MTU value for ICMPv6 error
 285  *
 286  * Return: length on success, negative error code if message couldn't be built.
 287  */
 288 static int iptunnel_pmtud_build_icmpv6(struct sk_buff *skb, int mtu)
 289 {
 290         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 291         struct icmp6hdr *icmp6h;
 292         struct ipv6hdr *nip6h;
 293         struct ethhdr eh;
 294         int len, err;
 295         __wsum csum;
 296
 297         if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct ipv6hdr)))
 298                 return -EINVAL;
 299
 300         skb_copy_bits(skb, skb_mac_offset(skb), &eh, ETH_HLEN);
 301         pskb_pull(skb, ETH_HLEN);
 302         skb_reset_network_header(skb);
 303
 304         err = pskb_trim(skb, IPV6_MIN_MTU - sizeof(*nip6h) - sizeof(*icmp6h));
 305         if (err)
 306                 return err;
 307
 308         len = skb->len + sizeof(*icmp6h);
 309         err = skb_cow(skb, sizeof(*nip6h) + sizeof(*icmp6h) + ETH_HLEN);
 310         if (err)
 311                 return err;
 312
 313         icmp6h = skb_push(skb, sizeof(*icmp6h));
 314         *icmp6h = (struct icmp6hdr) {
 315                 .icmp6_type             = ICMPV6_PKT_TOOBIG,
 316                 .icmp6_code             = 0,
 317                 .icmp6_cksum            = 0,
 318                 .icmp6_mtu              = htonl(mtu),
 319         };
 320         skb_reset_transport_header(skb);
 321
 322         nip6h = skb_push(skb, sizeof(*nip6h));
 323         *nip6h = (struct ipv6hdr) {
 324                 .priority               = 0,
 325                 .version                = 6,
 326                 .flow_lbl               = { 0 },
 327                 .payload_len            = htons(len),
 328                 .nexthdr                = IPPROTO_ICMPV6,
 329                 .hop_limit              = ip6h->hop_limit,
 330                 .saddr                  = ip6h->daddr,
 331                 .daddr                  = ip6h->saddr,
 332         };
 333         skb_reset_network_header(skb);
 334
 335         csum = csum_partial(icmp6h, len, 0);
 336         icmp6h->icmp6_cksum = csum_ipv6_magic(&nip6h->saddr, &nip6h->daddr, len,
 337                                               IPPROTO_ICMPV6, csum);
 338
 339         skb->ip_summed = CHECKSUM_NONE;
 340
 341         eth_header(skb, skb->dev, htons(eh.h_proto), eh.h_source, eh.h_dest, 0);
 342         skb_reset_mac_header(skb);
 343
 344         return skb->len;
 345 }
 346
 347 /**
 348  * iptunnel_pmtud_check_icmpv6() - Trigger ICMPv6 reply if needed and allowed
 349  * @skb:        Buffer being sent by encapsulation, L2 headers expected
 350  * @mtu:        Network MTU for path
 351  *
 352  * Return: 0 for no ICMPv6 reply, length if built, negative value on error.
 353  */
 354 static int iptunnel_pmtud_check_icmpv6(struct sk_buff *skb, int mtu)
 355 {
 356         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 357         int stype = ipv6_addr_type(&ip6h->saddr);
 358         u8 proto = ip6h->nexthdr;
 359         __be16 frag_off;
 360         int offset;
 361
 362         if (mtu < IPV6_MIN_MTU)
 363                 return 0;
 364
 365         if (stype == IPV6_ADDR_ANY || stype == IPV6_ADDR_MULTICAST ||
 366             stype == IPV6_ADDR_LOOPBACK)
 367                 return 0;
 368
 369         offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &proto,
 370                                   &frag_off);
 371         if (offset < 0 || (frag_off & htons(~0x7)))
 372                 return 0;
 373
 374         if (proto == IPPROTO_ICMPV6) {
 375                 struct icmp6hdr *icmp6h;
 376
 377                 if (!pskb_may_pull(skb, skb_network_header(skb) +
 378                                         offset + 1 - skb->data))
 379                         return 0;
 380
 381                 icmp6h = (struct icmp6hdr *)(skb_network_header(skb) + offset);
 382                 if (icmpv6_is_err(icmp6h->icmp6_type) ||
 383                     icmp6h->icmp6_type == NDISC_REDIRECT)
 384                         return 0;
 385         }
 386
 387         return iptunnel_pmtud_build_icmpv6(skb, mtu);
 388 }
 389 #endif /* IS_ENABLED(CONFIG_IPV6) */
 390
 391 /**
 392  * skb_tunnel_check_pmtu() - Check, update PMTU and trigger ICMP reply as needed
 393  * @skb:        Buffer being sent by encapsulation, L2 headers expected
 394  * @encap_dst:  Destination for tunnel encapsulation (outer IP)
 395  * @headroom:   Encapsulation header size, bytes
 396  * @reply:      Build matching ICMP or ICMPv6 message as a result
 397  *
 398  * L2 tunnel implementations that can carry IP and can be directly bridged
 399  * (currently UDP tunnels) can't always rely on IP forwarding paths to handle
 400  * PMTU discovery. In the bridged case, ICMP or ICMPv6 messages need to be built
 401  * based on payload and sent back by the encapsulation itself.
 402  *
 403  * For routable interfaces, we just need to update the PMTU for the destination.
 404  *
 405  * Return: 0 if ICMP error not needed, length if built, negative value on error
 406  */
 407 int skb_tunnel_check_pmtu(struct sk_buff *skb, struct dst_entry *encap_dst,
 408                           int headroom, bool reply)
 409 {
 410         u32 mtu = dst_mtu(encap_dst) - headroom;
 411
 412         if ((skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu)) ||
 413             (!skb_is_gso(skb) && (skb->len - skb_mac_header_len(skb)) <= mtu))
 414                 return 0;
 415
 416         skb_dst_update_pmtu_no_confirm(skb, mtu);
 417
 418         if (!reply || skb->pkt_type == PACKET_HOST)
 419                 return 0;
 420
 421         if (skb->protocol == htons(ETH_P_IP))
 422                 return iptunnel_pmtud_check_icmp(skb, mtu);
 423
 424 #if IS_ENABLED(CONFIG_IPV6)
 425         if (skb->protocol == htons(ETH_P_IPV6))
 426                 return iptunnel_pmtud_check_icmpv6(skb, mtu);
 427 #endif
 428         return 0;
 429 }
 430 EXPORT_SYMBOL(skb_tunnel_check_pmtu);
 431
 432 static const struct nla_policy ip_tun_policy[LWTUNNEL_IP_MAX + 1] = {
 433         [LWTUNNEL_IP_UNSPEC]    = { .strict_start_type = LWTUNNEL_IP_OPTS },
 434         [LWTUNNEL_IP_ID]        = { .type = NLA_U64 },
 435         [LWTUNNEL_IP_DST]       = { .type = NLA_U32 },
 436         [LWTUNNEL_IP_SRC]       = { .type = NLA_U32 },
 437         [LWTUNNEL_IP_TTL]       = { .type = NLA_U8 },
 438         [LWTUNNEL_IP_TOS]       = { .type = NLA_U8 },
 439         [LWTUNNEL_IP_FLAGS]     = { .type = NLA_U16 },
 440         [LWTUNNEL_IP_OPTS]      = { .type = NLA_NESTED },
 441 };
 442
 443 static const struct nla_policy ip_opts_policy[LWTUNNEL_IP_OPTS_MAX + 1] = {
 444         [LWTUNNEL_IP_OPTS_GENEVE]       = { .type = NLA_NESTED },
 445         [LWTUNNEL_IP_OPTS_VXLAN]        = { .type = NLA_NESTED },
 446         [LWTUNNEL_IP_OPTS_ERSPAN]       = { .type = NLA_NESTED },
 447 };
 448
 449 static const struct nla_policy
 450 geneve_opt_policy[LWTUNNEL_IP_OPT_GENEVE_MAX + 1] = {
 451         [LWTUNNEL_IP_OPT_GENEVE_CLASS]  = { .type = NLA_U16 },
 452         [LWTUNNEL_IP_OPT_GENEVE_TYPE]   = { .type = NLA_U8 },
 453         [LWTUNNEL_IP_OPT_GENEVE_DATA]   = { .type = NLA_BINARY, .len = 128 },
 454 };
 455
 456 static const struct nla_policy
 457 vxlan_opt_policy[LWTUNNEL_IP_OPT_VXLAN_MAX + 1] = {
 458         [LWTUNNEL_IP_OPT_VXLAN_GBP]     = { .type = NLA_U32 },
 459 };
 460
 461 static const struct nla_policy
 462 erspan_opt_policy[LWTUNNEL_IP_OPT_ERSPAN_MAX + 1] = {
 463         [LWTUNNEL_IP_OPT_ERSPAN_VER]    = { .type = NLA_U8 },
 464         [LWTUNNEL_IP_OPT_ERSPAN_INDEX]  = { .type = NLA_U32 },
 465         [LWTUNNEL_IP_OPT_ERSPAN_DIR]    = { .type = NLA_U8 },
 466         [LWTUNNEL_IP_OPT_ERSPAN_HWID]   = { .type = NLA_U8 },
 467 };
 468
 469 static int ip_tun_parse_opts_geneve(struct nlattr *attr,
 470                                     struct ip_tunnel_info *info, int opts_len,
 471                                     struct netlink_ext_ack *extack)
 472 {
 473         struct nlattr *tb[LWTUNNEL_IP_OPT_GENEVE_MAX + 1];
 474         int data_len, err;
 475
 476         err = nla_parse_nested(tb, LWTUNNEL_IP_OPT_GENEVE_MAX, attr,
 477                                geneve_opt_policy, extack);
 478         if (err)
 479                 return err;
 480
 481         if (!tb[LWTUNNEL_IP_OPT_GENEVE_CLASS] ||
 482             !tb[LWTUNNEL_IP_OPT_GENEVE_TYPE] ||
 483             !tb[LWTUNNEL_IP_OPT_GENEVE_DATA])
 484                 return -EINVAL;
 485
 486         attr = tb[LWTUNNEL_IP_OPT_GENEVE_DATA];
 487         data_len = nla_len(attr);
 488         if (data_len % 4)
 489                 return -EINVAL;
 490
 491         if (info) {
 492                 struct geneve_opt *opt = ip_tunnel_info_opts(info) + opts_len;
 493
 494                 memcpy(opt->opt_data, nla_data(attr), data_len);
 495                 opt->length = data_len / 4;
 496                 attr = tb[LWTUNNEL_IP_OPT_GENEVE_CLASS];
 497                 opt->opt_class = nla_get_be16(attr);
 498                 attr = tb[LWTUNNEL_IP_OPT_GENEVE_TYPE];
 499                 opt->type = nla_get_u8(attr);
 500                 info->key.tun_flags |= TUNNEL_GENEVE_OPT;
 501         }
 502
 503         return sizeof(struct geneve_opt) + data_len;
 504 }
 505
 506 static int ip_tun_parse_opts_vxlan(struct nlattr *attr,
 507                                    struct ip_tunnel_info *info, int opts_len,
 508                                    struct netlink_ext_ack *extack)
 509 {
 510         struct nlattr *tb[LWTUNNEL_IP_OPT_VXLAN_MAX + 1];
 511         int err;
 512
 513         err = nla_parse_nested(tb, LWTUNNEL_IP_OPT_VXLAN_MAX, attr,
 514                                vxlan_opt_policy, extack);
 515         if (err)
 516                 return err;
 517
 518         if (!tb[LWTUNNEL_IP_OPT_VXLAN_GBP])
 519                 return -EINVAL;
 520
 521         if (info) {
 522                 struct vxlan_metadata *md =
 523                         ip_tunnel_info_opts(info) + opts_len;
 524
 525                 attr = tb[LWTUNNEL_IP_OPT_VXLAN_GBP];
 526                 md->gbp = nla_get_u32(attr);
 527                 md->gbp &= VXLAN_GBP_MASK;
 528                 info->key.tun_flags |= TUNNEL_VXLAN_OPT;
 529         }
 530
 531         return sizeof(struct vxlan_metadata);
 532 }
 533
 534 static int ip_tun_parse_opts_erspan(struct nlattr *attr,
 535                                     struct ip_tunnel_info *info, int opts_len,
 536                                     struct netlink_ext_ack *extack)
 537 {
 538         struct nlattr *tb[LWTUNNEL_IP_OPT_ERSPAN_MAX + 1];
 539         int err;
 540         u8 ver;
 541
 542         err = nla_parse_nested(tb, LWTUNNEL_IP_OPT_ERSPAN_MAX, attr,
 543                                erspan_opt_policy, extack);
 544         if (err)
 545                 return err;
 546
 547         if (!tb[LWTUNNEL_IP_OPT_ERSPAN_VER])
 548                 return -EINVAL;
 549
 550         ver = nla_get_u8(tb[LWTUNNEL_IP_OPT_ERSPAN_VER]);
 551         if (ver == 1) {
 552                 if (!tb[LWTUNNEL_IP_OPT_ERSPAN_INDEX])
 553                         return -EINVAL;
 554         } else if (ver == 2) {
 555                 if (!tb[LWTUNNEL_IP_OPT_ERSPAN_DIR] ||
 556                     !tb[LWTUNNEL_IP_OPT_ERSPAN_HWID])
 557                         return -EINVAL;
 558         } else {
 559                 return -EINVAL;
 560         }
 561
 562         if (info) {
 563                 struct erspan_metadata *md =
 564                         ip_tunnel_info_opts(info) + opts_len;
 565
 566                 md->version = ver;
 567                 if (ver == 1) {
 568                         attr = tb[LWTUNNEL_IP_OPT_ERSPAN_INDEX];
 569                         md->u.index = nla_get_be32(attr);
 570                 } else {
 571                         attr = tb[LWTUNNEL_IP_OPT_ERSPAN_DIR];
 572                         md->u.md2.dir = nla_get_u8(attr);
 573                         attr = tb[LWTUNNEL_IP_OPT_ERSPAN_HWID];
 574                         set_hwid(&md->u.md2, nla_get_u8(attr));
 575                 }
 576
 577                 info->key.tun_flags |= TUNNEL_ERSPAN_OPT;
 578         }
 579
 580         return sizeof(struct erspan_metadata);
 581 }
 582
 583 static int ip_tun_parse_opts(struct nlattr *attr, struct ip_tunnel_info *info,
 584                              struct netlink_ext_ack *extack)
 585 {
 586         int err, rem, opt_len, opts_len = 0, type = 0;
 587         struct nlattr *nla;
 588
 589         if (!attr)
 590                 return 0;
 591
 592         err = nla_validate(nla_data(attr), nla_len(attr), LWTUNNEL_IP_OPTS_MAX,
 593                            ip_opts_policy, extack);
 594         if (err)
 595                 return err;
 596
 597         nla_for_each_attr(nla, nla_data(attr), nla_len(attr), rem) {
 598                 switch (nla_type(nla)) {
 599                 case LWTUNNEL_IP_OPTS_GENEVE:
 600                         if (type && type != TUNNEL_GENEVE_OPT)
 601                                 return -EINVAL;
 602                         opt_len = ip_tun_parse_opts_geneve(nla, info, opts_len,
 603                                                            extack);
 604                         if (opt_len < 0)
 605                                 return opt_len;
 606                         opts_len += opt_len;
 607                         if (opts_len > IP_TUNNEL_OPTS_MAX)
 608                                 return -EINVAL;
 609                         type = TUNNEL_GENEVE_OPT;
 610                         break;
 611                 case LWTUNNEL_IP_OPTS_VXLAN:
 612                         if (type)
 613                                 return -EINVAL;
 614                         opt_len = ip_tun_parse_opts_vxlan(nla, info, opts_len,
 615                                                           extack);
 616                         if (opt_len < 0)
 617                                 return opt_len;
 618                         opts_len += opt_len;
 619                         type = TUNNEL_VXLAN_OPT;
 620                         break;
 621                 case LWTUNNEL_IP_OPTS_ERSPAN:
 622                         if (type)
 623                                 return -EINVAL;
 624                         opt_len = ip_tun_parse_opts_erspan(nla, info, opts_len,
 625                                                            extack);
 626                         if (opt_len < 0)
 627                                 return opt_len;
 628                         opts_len += opt_len;
 629                         type = TUNNEL_ERSPAN_OPT;
 630                         break;
 631                 default:
 632                         return -EINVAL;
 633                 }
 634         }
 635
 636         return opts_len;
 637 }
 638
 639 static int ip_tun_get_optlen(struct nlattr *attr,
 640                              struct netlink_ext_ack *extack)
 641 {
 642         return ip_tun_parse_opts(attr, NULL, extack);
 643 }
 644
 645 static int ip_tun_set_opts(struct nlattr *attr, struct ip_tunnel_info *info,
 646                            struct netlink_ext_ack *extack)
 647 {
 648         return ip_tun_parse_opts(attr, info, extack);
 649 }
 650
 651 static int ip_tun_build_state(struct net *net, struct nlattr *attr,
 652                               unsigned int family, const void *cfg,
 653                               struct lwtunnel_state **ts,
 654                               struct netlink_ext_ack *extack)
 655 {
 656         struct nlattr *tb[LWTUNNEL_IP_MAX + 1];
 657         struct lwtunnel_state *new_state;
 658         struct ip_tunnel_info *tun_info;
 659         int err, opt_len;
 660
 661         err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP_MAX, attr,
 662                                           ip_tun_policy, extack);
 663         if (err < 0)
 664                 return err;
 665
 666         opt_len = ip_tun_get_optlen(tb[LWTUNNEL_IP_OPTS], extack);
 667         if (opt_len < 0)
 668                 return opt_len;
 669
 670         new_state = lwtunnel_state_alloc(sizeof(*tun_info) + opt_len);
 671         if (!new_state)
 672                 return -ENOMEM;
 673
 674         new_state->type = LWTUNNEL_ENCAP_IP;
 675
 676         tun_info = lwt_tun_info(new_state);
 677
 678         err = ip_tun_set_opts(tb[LWTUNNEL_IP_OPTS], tun_info, extack);
 679         if (err < 0) {
 680                 lwtstate_free(new_state);
 681                 return err;
 682         }
 683
 684 #ifdef CONFIG_DST_CACHE
 685         err = dst_cache_init(&tun_info->dst_cache, GFP_KERNEL);
 686         if (err) {
 687                 lwtstate_free(new_state);
 688                 return err;
 689         }
 690 #endif
 691
 692         if (tb[LWTUNNEL_IP_ID])
 693                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP_ID]);
 694
 695         if (tb[LWTUNNEL_IP_DST])
 696                 tun_info->key.u.ipv4.dst = nla_get_in_addr(tb[LWTUNNEL_IP_DST]);
 697
 698         if (tb[LWTUNNEL_IP_SRC])
 699                 tun_info->key.u.ipv4.src = nla_get_in_addr(tb[LWTUNNEL_IP_SRC]);
 700
 701         if (tb[LWTUNNEL_IP_TTL])
 702                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP_TTL]);
 703
 704         if (tb[LWTUNNEL_IP_TOS])
 705                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP_TOS]);
 706
 707         if (tb[LWTUNNEL_IP_FLAGS])
 708                 tun_info->key.tun_flags |=
 709                                 (nla_get_be16(tb[LWTUNNEL_IP_FLAGS]) &
 710                                  ~TUNNEL_OPTIONS_PRESENT);
 711
 712         tun_info->mode = IP_TUNNEL_INFO_TX;
 713         tun_info->options_len = opt_len;
 714
 715         *ts = new_state;
 716
 717         return 0;
 718 }
 719
 720 static void ip_tun_destroy_state(struct lwtunnel_state *lwtstate)
 721 {
 722 #ifdef CONFIG_DST_CACHE
 723         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 724
 725         dst_cache_destroy(&tun_info->dst_cache);
 726 #endif
 727 }
 728
 729 static int ip_tun_fill_encap_opts_geneve(struct sk_buff *skb,
 730                                          struct ip_tunnel_info *tun_info)
 731 {
 732         struct geneve_opt *opt;
 733         struct nlattr *nest;
 734         int offset = 0;
 735
 736         nest = nla_nest_start_noflag(skb, LWTUNNEL_IP_OPTS_GENEVE);
 737         if (!nest)
 738                 return -ENOMEM;
 739
 740         while (tun_info->options_len > offset) {
 741                 opt = ip_tunnel_info_opts(tun_info) + offset;
 742                 if (nla_put_be16(skb, LWTUNNEL_IP_OPT_GENEVE_CLASS,
 743                                  opt->opt_class) ||
 744                     nla_put_u8(skb, LWTUNNEL_IP_OPT_GENEVE_TYPE, opt->type) ||
 745                     nla_put(skb, LWTUNNEL_IP_OPT_GENEVE_DATA, opt->length * 4,
 746                             opt->opt_data)) {
 747                         nla_nest_cancel(skb, nest);
 748                         return -ENOMEM;
 749                 }
 750                 offset += sizeof(*opt) + opt->length * 4;
 751         }
 752
 753         nla_nest_end(skb, nest);
 754         return 0;
 755 }
 756
 757 static int ip_tun_fill_encap_opts_vxlan(struct sk_buff *skb,
 758                                         struct ip_tunnel_info *tun_info)
 759 {
 760         struct vxlan_metadata *md;
 761         struct nlattr *nest;
 762
 763         nest = nla_nest_start_noflag(skb, LWTUNNEL_IP_OPTS_VXLAN);
 764         if (!nest)
 765                 return -ENOMEM;
 766
 767         md = ip_tunnel_info_opts(tun_info);
 768         if (nla_put_u32(skb, LWTUNNEL_IP_OPT_VXLAN_GBP, md->gbp)) {
 769                 nla_nest_cancel(skb, nest);
 770                 return -ENOMEM;
 771         }
 772
 773         nla_nest_end(skb, nest);
 774         return 0;
 775 }
 776
 777 static int ip_tun_fill_encap_opts_erspan(struct sk_buff *skb,
 778                                          struct ip_tunnel_info *tun_info)
 779 {
 780         struct erspan_metadata *md;
 781         struct nlattr *nest;
 782
 783         nest = nla_nest_start_noflag(skb, LWTUNNEL_IP_OPTS_ERSPAN);
 784         if (!nest)
 785                 return -ENOMEM;
 786
 787         md = ip_tunnel_info_opts(tun_info);
 788         if (nla_put_u8(skb, LWTUNNEL_IP_OPT_ERSPAN_VER, md->version))
 789                 goto err;
 790
 791         if (md->version == 1 &&
 792             nla_put_be32(skb, LWTUNNEL_IP_OPT_ERSPAN_INDEX, md->u.index))
 793                 goto err;
 794
 795         if (md->version == 2 &&
 796             (nla_put_u8(skb, LWTUNNEL_IP_OPT_ERSPAN_DIR, md->u.md2.dir) ||
 797              nla_put_u8(skb, LWTUNNEL_IP_OPT_ERSPAN_HWID,
 798                         get_hwid(&md->u.md2))))
 799                 goto err;
 800
 801         nla_nest_end(skb, nest);
 802         return 0;
 803 err:
 804         nla_nest_cancel(skb, nest);
 805         return -ENOMEM;
 806 }
 807
 808 static int ip_tun_fill_encap_opts(struct sk_buff *skb, int type,
 809                                   struct ip_tunnel_info *tun_info)
 810 {
 811         struct nlattr *nest;
 812         int err = 0;
 813
 814         if (!(tun_info->key.tun_flags & TUNNEL_OPTIONS_PRESENT))
 815                 return 0;
 816
 817         nest = nla_nest_start_noflag(skb, type);
 818         if (!nest)
 819                 return -ENOMEM;
 820
 821         if (tun_info->key.tun_flags & TUNNEL_GENEVE_OPT)
 822                 err = ip_tun_fill_encap_opts_geneve(skb, tun_info);
 823         else if (tun_info->key.tun_flags & TUNNEL_VXLAN_OPT)
 824                 err = ip_tun_fill_encap_opts_vxlan(skb, tun_info);
 825         else if (tun_info->key.tun_flags & TUNNEL_ERSPAN_OPT)
 826                 err = ip_tun_fill_encap_opts_erspan(skb, tun_info);
 827
 828         if (err) {
 829                 nla_nest_cancel(skb, nest);
 830                 return err;
 831         }
 832
 833         nla_nest_end(skb, nest);
 834         return 0;
 835 }
 836
 837 static int ip_tun_fill_encap_info(struct sk_buff *skb,
 838                                   struct lwtunnel_state *lwtstate)
 839 {
 840         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 841
 842         if (nla_put_be64(skb, LWTUNNEL_IP_ID, tun_info->key.tun_id,
 843                          LWTUNNEL_IP_PAD) ||
 844             nla_put_in_addr(skb, LWTUNNEL_IP_DST, tun_info->key.u.ipv4.dst) ||
 845             nla_put_in_addr(skb, LWTUNNEL_IP_SRC, tun_info->key.u.ipv4.src) ||
 846             nla_put_u8(skb, LWTUNNEL_IP_TOS, tun_info->key.tos) ||
 847             nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||
 848             nla_put_be16(skb, LWTUNNEL_IP_FLAGS, tun_info->key.tun_flags) ||
 849             ip_tun_fill_encap_opts(skb, LWTUNNEL_IP_OPTS, tun_info))
 850                 return -ENOMEM;
 851
 852         return 0;
 853 }
 854
 855 static int ip_tun_opts_nlsize(struct ip_tunnel_info *info)
 856 {
 857         int opt_len;
 858
 859         if (!(info->key.tun_flags & TUNNEL_OPTIONS_PRESENT))
 860                 return 0;
 861
 862         opt_len = nla_total_size(0);            /* LWTUNNEL_IP_OPTS */
 863         if (info->key.tun_flags & TUNNEL_GENEVE_OPT) {
 864                 struct geneve_opt *opt;
 865                 int offset = 0;
 866
 867                 opt_len += nla_total_size(0);   /* LWTUNNEL_IP_OPTS_GENEVE */
 868                 while (info->options_len > offset) {
 869                         opt = ip_tunnel_info_opts(info) + offset;
 870                         opt_len += nla_total_size(2)    /* OPT_GENEVE_CLASS */
 871                                    + nla_total_size(1)  /* OPT_GENEVE_TYPE */
 872                                    + nla_total_size(opt->length * 4);
 873                                                         /* OPT_GENEVE_DATA */
 874                         offset += sizeof(*opt) + opt->length * 4;
 875                 }
 876         } else if (info->key.tun_flags & TUNNEL_VXLAN_OPT) {
 877                 opt_len += nla_total_size(0)    /* LWTUNNEL_IP_OPTS_VXLAN */
 878                            + nla_total_size(4); /* OPT_VXLAN_GBP */
 879         } else if (info->key.tun_flags & TUNNEL_ERSPAN_OPT) {
 880                 struct erspan_metadata *md = ip_tunnel_info_opts(info);
 881
 882                 opt_len += nla_total_size(0)    /* LWTUNNEL_IP_OPTS_ERSPAN */
 883                            + nla_total_size(1)  /* OPT_ERSPAN_VER */
 884                            + (md->version == 1 ? nla_total_size(4)
 885                                                 /* OPT_ERSPAN_INDEX (v1) */
 886                                                : nla_total_size(1) +
 887                                                  nla_total_size(1));
 888                                                 /* OPT_ERSPAN_DIR + HWID (v2) */
 889         }
 890
 891         return opt_len;
 892 }
 893
 894 static int ip_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 895 {
 896         return nla_total_size_64bit(8)  /* LWTUNNEL_IP_ID */
 897                 + nla_total_size(4)     /* LWTUNNEL_IP_DST */
 898                 + nla_total_size(4)     /* LWTUNNEL_IP_SRC */
 899                 + nla_total_size(1)     /* LWTUNNEL_IP_TOS */
 900                 + nla_total_size(1)     /* LWTUNNEL_IP_TTL */
 901                 + nla_total_size(2)     /* LWTUNNEL_IP_FLAGS */
 902                 + ip_tun_opts_nlsize(lwt_tun_info(lwtstate));
 903                                         /* LWTUNNEL_IP_OPTS */
 904 }
 905
 906 static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
 907 {
 908         struct ip_tunnel_info *info_a = lwt_tun_info(a);
 909         struct ip_tunnel_info *info_b = lwt_tun_info(b);
 910
 911         return memcmp(info_a, info_b, sizeof(info_a->key)) ||
 912                info_a->mode != info_b->mode ||
 913                info_a->options_len != info_b->options_len ||
 914                memcmp(ip_tunnel_info_opts(info_a),
 915                       ip_tunnel_info_opts(info_b), info_a->options_len);
 916 }
 917
 918 static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
 919         .build_state = ip_tun_build_state,
 920         .destroy_state = ip_tun_destroy_state,
 921         .fill_encap = ip_tun_fill_encap_info,
 922         .get_encap_size = ip_tun_encap_nlsize,
 923         .cmp_encap = ip_tun_cmp_encap,
 924         .owner = THIS_MODULE,
 925 };
 926
 927 static const struct nla_policy ip6_tun_policy[LWTUNNEL_IP6_MAX + 1] = {
 928         [LWTUNNEL_IP6_UNSPEC]   = { .strict_start_type = LWTUNNEL_IP6_OPTS },
 929         [LWTUNNEL_IP6_ID]               = { .type = NLA_U64 },
 930         [LWTUNNEL_IP6_DST]              = { .len = sizeof(struct in6_addr) },
 931         [LWTUNNEL_IP6_SRC]              = { .len = sizeof(struct in6_addr) },
 932         [LWTUNNEL_IP6_HOPLIMIT]         = { .type = NLA_U8 },
 933         [LWTUNNEL_IP6_TC]               = { .type = NLA_U8 },
 934         [LWTUNNEL_IP6_FLAGS]            = { .type = NLA_U16 },
 935         [LWTUNNEL_IP6_OPTS]             = { .type = NLA_NESTED },
 936 };
 937
 938 static int ip6_tun_build_state(struct net *net, struct nlattr *attr,
 939                                unsigned int family, const void *cfg,
 940                                struct lwtunnel_state **ts,
 941                                struct netlink_ext_ack *extack)
 942 {
 943         struct nlattr *tb[LWTUNNEL_IP6_MAX + 1];
 944         struct lwtunnel_state *new_state;
 945         struct ip_tunnel_info *tun_info;
 946         int err, opt_len;
 947
 948         err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP6_MAX, attr,
 949                                           ip6_tun_policy, extack);
 950         if (err < 0)
 951                 return err;
 952
 953         opt_len = ip_tun_get_optlen(tb[LWTUNNEL_IP6_OPTS], extack);
 954         if (opt_len < 0)
 955                 return opt_len;
 956
 957         new_state = lwtunnel_state_alloc(sizeof(*tun_info) + opt_len);
 958         if (!new_state)
 959                 return -ENOMEM;
 960
 961         new_state->type = LWTUNNEL_ENCAP_IP6;
 962
 963         tun_info = lwt_tun_info(new_state);
 964
 965         err = ip_tun_set_opts(tb[LWTUNNEL_IP6_OPTS], tun_info, extack);
 966         if (err < 0) {
 967                 lwtstate_free(new_state);
 968                 return err;
 969         }
 970
 971         if (tb[LWTUNNEL_IP6_ID])
 972                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP6_ID]);
 973
 974         if (tb[LWTUNNEL_IP6_DST])
 975                 tun_info->key.u.ipv6.dst = nla_get_in6_addr(tb[LWTUNNEL_IP6_DST]);
 976
 977         if (tb[LWTUNNEL_IP6_SRC])
 978                 tun_info->key.u.ipv6.src = nla_get_in6_addr(tb[LWTUNNEL_IP6_SRC]);
 979
 980         if (tb[LWTUNNEL_IP6_HOPLIMIT])
 981                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP6_HOPLIMIT]);
 982
 983         if (tb[LWTUNNEL_IP6_TC])
 984                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP6_TC]);
 985
 986         if (tb[LWTUNNEL_IP6_FLAGS])
 987                 tun_info->key.tun_flags |=
 988                                 (nla_get_be16(tb[LWTUNNEL_IP6_FLAGS]) &
 989                                  ~TUNNEL_OPTIONS_PRESENT);
 990
 991         tun_info->mode = IP_TUNNEL_INFO_TX | IP_TUNNEL_INFO_IPV6;
 992         tun_info->options_len = opt_len;
 993
 994         *ts = new_state;
 995
 996         return 0;
 997 }
 998
 999 static int ip6_tun_fill_encap_info(struct sk_buff *skb,
1000                                    struct lwtunnel_state *lwtstate)
1001 {
1002         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
1003
1004         if (nla_put_be64(skb, LWTUNNEL_IP6_ID, tun_info->key.tun_id,
1005                          LWTUNNEL_IP6_PAD) ||
1006             nla_put_in6_addr(skb, LWTUNNEL_IP6_DST, &tun_info->key.u.ipv6.dst) ||
1007             nla_put_in6_addr(skb, LWTUNNEL_IP6_SRC, &tun_info->key.u.ipv6.src) ||
1008             nla_put_u8(skb, LWTUNNEL_IP6_TC, tun_info->key.tos) ||
1009             nla_put_u8(skb, LWTUNNEL_IP6_HOPLIMIT, tun_info->key.ttl) ||
1010             nla_put_be16(skb, LWTUNNEL_IP6_FLAGS, tun_info->key.tun_flags) ||
1011             ip_tun_fill_encap_opts(skb, LWTUNNEL_IP6_OPTS, tun_info))
1012                 return -ENOMEM;
1013
1014         return 0;
1015 }
1016
1017 static int ip6_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
1018 {
1019         return nla_total_size_64bit(8)  /* LWTUNNEL_IP6_ID */
1020                 + nla_total_size(16)    /* LWTUNNEL_IP6_DST */
1021                 + nla_total_size(16)    /* LWTUNNEL_IP6_SRC */
1022                 + nla_total_size(1)     /* LWTUNNEL_IP6_HOPLIMIT */
1023                 + nla_total_size(1)     /* LWTUNNEL_IP6_TC */
1024                 + nla_total_size(2)     /* LWTUNNEL_IP6_FLAGS */
1025                 + ip_tun_opts_nlsize(lwt_tun_info(lwtstate));
1026                                         /* LWTUNNEL_IP6_OPTS */
1027 }
1028
1029 static const struct lwtunnel_encap_ops ip6_tun_lwt_ops = {
1030         .build_state = ip6_tun_build_state,
1031         .fill_encap = ip6_tun_fill_encap_info,
1032         .get_encap_size = ip6_tun_encap_nlsize,
1033         .cmp_encap = ip_tun_cmp_encap,
1034         .owner = THIS_MODULE,
1035 };
1036
1037 void __init ip_tunnel_core_init(void)
1038 {
1039         /* If you land here, make sure whether increasing ip_tunnel_info's
1040          * options_len is a reasonable choice with its usage in front ends
1041          * (f.e., it's part of flow keys, etc).
1042          */
1043         BUILD_BUG_ON(IP_TUNNEL_OPTS_MAX != 255);
1044
1045         lwtunnel_encap_add_ops(&ip_tun_lwt_ops, LWTUNNEL_ENCAP_IP);
1046         lwtunnel_encap_add_ops(&ip6_tun_lwt_ops, LWTUNNEL_ENCAP_IP6);
1047 }
1048
1049 DEFINE_STATIC_KEY_FALSE(ip_tunnel_metadata_cnt);
1050 EXPORT_SYMBOL(ip_tunnel_metadata_cnt);
1051
1052 void ip_tunnel_need_metadata(void)
1053 {
1054         static_branch_inc(&ip_tunnel_metadata_cnt);
1055 }
1056 EXPORT_SYMBOL_GPL(ip_tunnel_need_metadata);
1057
1058 void ip_tunnel_unneed_metadata(void)
1059 {
1060         static_branch_dec(&ip_tunnel_metadata_cnt);
1061 }
1062 EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata);
1063
1064 /* Returns either the correct skb->protocol value, or 0 if invalid. */
1065 __be16 ip_tunnel_parse_protocol(const struct sk_buff *skb)
1066 {
1067         if (skb_network_header(skb) >= skb->head &&
1068             (skb_network_header(skb) + sizeof(struct iphdr)) <= skb_tail_pointer(skb) &&
1069             ip_hdr(skb)->version == 4)
1070                 return htons(ETH_P_IP);
1071         if (skb_network_header(skb) >= skb->head &&
1072             (skb_network_header(skb) + sizeof(struct ipv6hdr)) <= skb_tail_pointer(skb) &&
1073             ipv6_hdr(skb)->version == 6)
1074                 return htons(ETH_P_IPV6);
1075         return 0;
1076 }
1077 EXPORT_SYMBOL(ip_tunnel_parse_protocol);
1078
1079 const struct header_ops ip_tunnel_header_ops = { .parse_protocol = ip_tunnel_parse_protocol };
1080 EXPORT_SYMBOL(ip_tunnel_header_ops);