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 /* Often modified stats are per cpu, other are shared (netdev->stats) */
 433 void ip_tunnel_get_stats64(struct net_device *dev,
 434                            struct rtnl_link_stats64 *tot)
 435 {
 436         netdev_stats_to_stats64(tot, &dev->stats);
 437         dev_fetch_sw_netstats(tot, dev->tstats);
 438 }
 439 EXPORT_SYMBOL_GPL(ip_tunnel_get_stats64);
 440
 441 static const struct nla_policy ip_tun_policy[LWTUNNEL_IP_MAX + 1] = {
 442         [LWTUNNEL_IP_UNSPEC]    = { .strict_start_type = LWTUNNEL_IP_OPTS },
 443         [LWTUNNEL_IP_ID]        = { .type = NLA_U64 },
 444         [LWTUNNEL_IP_DST]       = { .type = NLA_U32 },
 445         [LWTUNNEL_IP_SRC]       = { .type = NLA_U32 },
 446         [LWTUNNEL_IP_TTL]       = { .type = NLA_U8 },
 447         [LWTUNNEL_IP_TOS]       = { .type = NLA_U8 },
 448         [LWTUNNEL_IP_FLAGS]     = { .type = NLA_U16 },
 449         [LWTUNNEL_IP_OPTS]      = { .type = NLA_NESTED },
 450 };
 451
 452 static const struct nla_policy ip_opts_policy[LWTUNNEL_IP_OPTS_MAX + 1] = {
 453         [LWTUNNEL_IP_OPTS_GENEVE]       = { .type = NLA_NESTED },
 454         [LWTUNNEL_IP_OPTS_VXLAN]        = { .type = NLA_NESTED },
 455         [LWTUNNEL_IP_OPTS_ERSPAN]       = { .type = NLA_NESTED },
 456 };
 457
 458 static const struct nla_policy
 459 geneve_opt_policy[LWTUNNEL_IP_OPT_GENEVE_MAX + 1] = {
 460         [LWTUNNEL_IP_OPT_GENEVE_CLASS]  = { .type = NLA_U16 },
 461         [LWTUNNEL_IP_OPT_GENEVE_TYPE]   = { .type = NLA_U8 },
 462         [LWTUNNEL_IP_OPT_GENEVE_DATA]   = { .type = NLA_BINARY, .len = 128 },
 463 };
 464
 465 static const struct nla_policy
 466 vxlan_opt_policy[LWTUNNEL_IP_OPT_VXLAN_MAX + 1] = {
 467         [LWTUNNEL_IP_OPT_VXLAN_GBP]     = { .type = NLA_U32 },
 468 };
 469
 470 static const struct nla_policy
 471 erspan_opt_policy[LWTUNNEL_IP_OPT_ERSPAN_MAX + 1] = {
 472         [LWTUNNEL_IP_OPT_ERSPAN_VER]    = { .type = NLA_U8 },
 473         [LWTUNNEL_IP_OPT_ERSPAN_INDEX]  = { .type = NLA_U32 },
 474         [LWTUNNEL_IP_OPT_ERSPAN_DIR]    = { .type = NLA_U8 },
 475         [LWTUNNEL_IP_OPT_ERSPAN_HWID]   = { .type = NLA_U8 },
 476 };
 477
 478 static int ip_tun_parse_opts_geneve(struct nlattr *attr,
 479                                     struct ip_tunnel_info *info, int opts_len,
 480                                     struct netlink_ext_ack *extack)
 481 {
 482         struct nlattr *tb[LWTUNNEL_IP_OPT_GENEVE_MAX + 1];
 483         int data_len, err;
 484
 485         err = nla_parse_nested(tb, LWTUNNEL_IP_OPT_GENEVE_MAX, attr,
 486                                geneve_opt_policy, extack);
 487         if (err)
 488                 return err;
 489
 490         if (!tb[LWTUNNEL_IP_OPT_GENEVE_CLASS] ||
 491             !tb[LWTUNNEL_IP_OPT_GENEVE_TYPE] ||
 492             !tb[LWTUNNEL_IP_OPT_GENEVE_DATA])
 493                 return -EINVAL;
 494
 495         attr = tb[LWTUNNEL_IP_OPT_GENEVE_DATA];
 496         data_len = nla_len(attr);
 497         if (data_len % 4)
 498                 return -EINVAL;
 499
 500         if (info) {
 501                 struct geneve_opt *opt = ip_tunnel_info_opts(info) + opts_len;
 502
 503                 memcpy(opt->opt_data, nla_data(attr), data_len);
 504                 opt->length = data_len / 4;
 505                 attr = tb[LWTUNNEL_IP_OPT_GENEVE_CLASS];
 506                 opt->opt_class = nla_get_be16(attr);
 507                 attr = tb[LWTUNNEL_IP_OPT_GENEVE_TYPE];
 508                 opt->type = nla_get_u8(attr);
 509                 info->key.tun_flags |= TUNNEL_GENEVE_OPT;
 510         }
 511
 512         return sizeof(struct geneve_opt) + data_len;
 513 }
 514
 515 static int ip_tun_parse_opts_vxlan(struct nlattr *attr,
 516                                    struct ip_tunnel_info *info, int opts_len,
 517                                    struct netlink_ext_ack *extack)
 518 {
 519         struct nlattr *tb[LWTUNNEL_IP_OPT_VXLAN_MAX + 1];
 520         int err;
 521
 522         err = nla_parse_nested(tb, LWTUNNEL_IP_OPT_VXLAN_MAX, attr,
 523                                vxlan_opt_policy, extack);
 524         if (err)
 525                 return err;
 526
 527         if (!tb[LWTUNNEL_IP_OPT_VXLAN_GBP])
 528                 return -EINVAL;
 529
 530         if (info) {
 531                 struct vxlan_metadata *md =
 532                         ip_tunnel_info_opts(info) + opts_len;
 533
 534                 attr = tb[LWTUNNEL_IP_OPT_VXLAN_GBP];
 535                 md->gbp = nla_get_u32(attr);
 536                 md->gbp &= VXLAN_GBP_MASK;
 537                 info->key.tun_flags |= TUNNEL_VXLAN_OPT;
 538         }
 539
 540         return sizeof(struct vxlan_metadata);
 541 }
 542
 543 static int ip_tun_parse_opts_erspan(struct nlattr *attr,
 544                                     struct ip_tunnel_info *info, int opts_len,
 545                                     struct netlink_ext_ack *extack)
 546 {
 547         struct nlattr *tb[LWTUNNEL_IP_OPT_ERSPAN_MAX + 1];
 548         int err;
 549         u8 ver;
 550
 551         err = nla_parse_nested(tb, LWTUNNEL_IP_OPT_ERSPAN_MAX, attr,
 552                                erspan_opt_policy, extack);
 553         if (err)
 554                 return err;
 555
 556         if (!tb[LWTUNNEL_IP_OPT_ERSPAN_VER])
 557                 return -EINVAL;
 558
 559         ver = nla_get_u8(tb[LWTUNNEL_IP_OPT_ERSPAN_VER]);
 560         if (ver == 1) {
 561                 if (!tb[LWTUNNEL_IP_OPT_ERSPAN_INDEX])
 562                         return -EINVAL;
 563         } else if (ver == 2) {
 564                 if (!tb[LWTUNNEL_IP_OPT_ERSPAN_DIR] ||
 565                     !tb[LWTUNNEL_IP_OPT_ERSPAN_HWID])
 566                         return -EINVAL;
 567         } else {
 568                 return -EINVAL;
 569         }
 570
 571         if (info) {
 572                 struct erspan_metadata *md =
 573                         ip_tunnel_info_opts(info) + opts_len;
 574
 575                 md->version = ver;
 576                 if (ver == 1) {
 577                         attr = tb[LWTUNNEL_IP_OPT_ERSPAN_INDEX];
 578                         md->u.index = nla_get_be32(attr);
 579                 } else {
 580                         attr = tb[LWTUNNEL_IP_OPT_ERSPAN_DIR];
 581                         md->u.md2.dir = nla_get_u8(attr);
 582                         attr = tb[LWTUNNEL_IP_OPT_ERSPAN_HWID];
 583                         set_hwid(&md->u.md2, nla_get_u8(attr));
 584                 }
 585
 586                 info->key.tun_flags |= TUNNEL_ERSPAN_OPT;
 587         }
 588
 589         return sizeof(struct erspan_metadata);
 590 }
 591
 592 static int ip_tun_parse_opts(struct nlattr *attr, struct ip_tunnel_info *info,
 593                              struct netlink_ext_ack *extack)
 594 {
 595         int err, rem, opt_len, opts_len = 0, type = 0;
 596         struct nlattr *nla;
 597
 598         if (!attr)
 599                 return 0;
 600
 601         err = nla_validate(nla_data(attr), nla_len(attr), LWTUNNEL_IP_OPTS_MAX,
 602                            ip_opts_policy, extack);
 603         if (err)
 604                 return err;
 605
 606         nla_for_each_attr(nla, nla_data(attr), nla_len(attr), rem) {
 607                 switch (nla_type(nla)) {
 608                 case LWTUNNEL_IP_OPTS_GENEVE:
 609                         if (type && type != TUNNEL_GENEVE_OPT)
 610                                 return -EINVAL;
 611                         opt_len = ip_tun_parse_opts_geneve(nla, info, opts_len,
 612                                                            extack);
 613                         if (opt_len < 0)
 614                                 return opt_len;
 615                         opts_len += opt_len;
 616                         if (opts_len > IP_TUNNEL_OPTS_MAX)
 617                                 return -EINVAL;
 618                         type = TUNNEL_GENEVE_OPT;
 619                         break;
 620                 case LWTUNNEL_IP_OPTS_VXLAN:
 621                         if (type)
 622                                 return -EINVAL;
 623                         opt_len = ip_tun_parse_opts_vxlan(nla, info, opts_len,
 624                                                           extack);
 625                         if (opt_len < 0)
 626                                 return opt_len;
 627                         opts_len += opt_len;
 628                         type = TUNNEL_VXLAN_OPT;
 629                         break;
 630                 case LWTUNNEL_IP_OPTS_ERSPAN:
 631                         if (type)
 632                                 return -EINVAL;
 633                         opt_len = ip_tun_parse_opts_erspan(nla, info, opts_len,
 634                                                            extack);
 635                         if (opt_len < 0)
 636                                 return opt_len;
 637                         opts_len += opt_len;
 638                         type = TUNNEL_ERSPAN_OPT;
 639                         break;
 640                 default:
 641                         return -EINVAL;
 642                 }
 643         }
 644
 645         return opts_len;
 646 }
 647
 648 static int ip_tun_get_optlen(struct nlattr *attr,
 649                              struct netlink_ext_ack *extack)
 650 {
 651         return ip_tun_parse_opts(attr, NULL, extack);
 652 }
 653
 654 static int ip_tun_set_opts(struct nlattr *attr, struct ip_tunnel_info *info,
 655                            struct netlink_ext_ack *extack)
 656 {
 657         return ip_tun_parse_opts(attr, info, extack);
 658 }
 659
 660 static int ip_tun_build_state(struct net *net, struct nlattr *attr,
 661                               unsigned int family, const void *cfg,
 662                               struct lwtunnel_state **ts,
 663                               struct netlink_ext_ack *extack)
 664 {
 665         struct nlattr *tb[LWTUNNEL_IP_MAX + 1];
 666         struct lwtunnel_state *new_state;
 667         struct ip_tunnel_info *tun_info;
 668         int err, opt_len;
 669
 670         err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP_MAX, attr,
 671                                           ip_tun_policy, extack);
 672         if (err < 0)
 673                 return err;
 674
 675         opt_len = ip_tun_get_optlen(tb[LWTUNNEL_IP_OPTS], extack);
 676         if (opt_len < 0)
 677                 return opt_len;
 678
 679         new_state = lwtunnel_state_alloc(sizeof(*tun_info) + opt_len);
 680         if (!new_state)
 681                 return -ENOMEM;
 682
 683         new_state->type = LWTUNNEL_ENCAP_IP;
 684
 685         tun_info = lwt_tun_info(new_state);
 686
 687         err = ip_tun_set_opts(tb[LWTUNNEL_IP_OPTS], tun_info, extack);
 688         if (err < 0) {
 689                 lwtstate_free(new_state);
 690                 return err;
 691         }
 692
 693 #ifdef CONFIG_DST_CACHE
 694         err = dst_cache_init(&tun_info->dst_cache, GFP_KERNEL);
 695         if (err) {
 696                 lwtstate_free(new_state);
 697                 return err;
 698         }
 699 #endif
 700
 701         if (tb[LWTUNNEL_IP_ID])
 702                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP_ID]);
 703
 704         if (tb[LWTUNNEL_IP_DST])
 705                 tun_info->key.u.ipv4.dst = nla_get_in_addr(tb[LWTUNNEL_IP_DST]);
 706
 707         if (tb[LWTUNNEL_IP_SRC])
 708                 tun_info->key.u.ipv4.src = nla_get_in_addr(tb[LWTUNNEL_IP_SRC]);
 709
 710         if (tb[LWTUNNEL_IP_TTL])
 711                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP_TTL]);
 712
 713         if (tb[LWTUNNEL_IP_TOS])
 714                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP_TOS]);
 715
 716         if (tb[LWTUNNEL_IP_FLAGS])
 717                 tun_info->key.tun_flags |=
 718                                 (nla_get_be16(tb[LWTUNNEL_IP_FLAGS]) &
 719                                  ~TUNNEL_OPTIONS_PRESENT);
 720
 721         tun_info->mode = IP_TUNNEL_INFO_TX;
 722         tun_info->options_len = opt_len;
 723
 724         *ts = new_state;
 725
 726         return 0;
 727 }
 728
 729 static void ip_tun_destroy_state(struct lwtunnel_state *lwtstate)
 730 {
 731 #ifdef CONFIG_DST_CACHE
 732         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 733
 734         dst_cache_destroy(&tun_info->dst_cache);
 735 #endif
 736 }
 737
 738 static int ip_tun_fill_encap_opts_geneve(struct sk_buff *skb,
 739                                          struct ip_tunnel_info *tun_info)
 740 {
 741         struct geneve_opt *opt;
 742         struct nlattr *nest;
 743         int offset = 0;
 744
 745         nest = nla_nest_start_noflag(skb, LWTUNNEL_IP_OPTS_GENEVE);
 746         if (!nest)
 747                 return -ENOMEM;
 748
 749         while (tun_info->options_len > offset) {
 750                 opt = ip_tunnel_info_opts(tun_info) + offset;
 751                 if (nla_put_be16(skb, LWTUNNEL_IP_OPT_GENEVE_CLASS,
 752                                  opt->opt_class) ||
 753                     nla_put_u8(skb, LWTUNNEL_IP_OPT_GENEVE_TYPE, opt->type) ||
 754                     nla_put(skb, LWTUNNEL_IP_OPT_GENEVE_DATA, opt->length * 4,
 755                             opt->opt_data)) {
 756                         nla_nest_cancel(skb, nest);
 757                         return -ENOMEM;
 758                 }
 759                 offset += sizeof(*opt) + opt->length * 4;
 760         }
 761
 762         nla_nest_end(skb, nest);
 763         return 0;
 764 }
 765
 766 static int ip_tun_fill_encap_opts_vxlan(struct sk_buff *skb,
 767                                         struct ip_tunnel_info *tun_info)
 768 {
 769         struct vxlan_metadata *md;
 770         struct nlattr *nest;
 771
 772         nest = nla_nest_start_noflag(skb, LWTUNNEL_IP_OPTS_VXLAN);
 773         if (!nest)
 774                 return -ENOMEM;
 775
 776         md = ip_tunnel_info_opts(tun_info);
 777         if (nla_put_u32(skb, LWTUNNEL_IP_OPT_VXLAN_GBP, md->gbp)) {
 778                 nla_nest_cancel(skb, nest);
 779                 return -ENOMEM;
 780         }
 781
 782         nla_nest_end(skb, nest);
 783         return 0;
 784 }
 785
 786 static int ip_tun_fill_encap_opts_erspan(struct sk_buff *skb,
 787                                          struct ip_tunnel_info *tun_info)
 788 {
 789         struct erspan_metadata *md;
 790         struct nlattr *nest;
 791
 792         nest = nla_nest_start_noflag(skb, LWTUNNEL_IP_OPTS_ERSPAN);
 793         if (!nest)
 794                 return -ENOMEM;
 795
 796         md = ip_tunnel_info_opts(tun_info);
 797         if (nla_put_u8(skb, LWTUNNEL_IP_OPT_ERSPAN_VER, md->version))
 798                 goto err;
 799
 800         if (md->version == 1 &&
 801             nla_put_be32(skb, LWTUNNEL_IP_OPT_ERSPAN_INDEX, md->u.index))
 802                 goto err;
 803
 804         if (md->version == 2 &&
 805             (nla_put_u8(skb, LWTUNNEL_IP_OPT_ERSPAN_DIR, md->u.md2.dir) ||
 806              nla_put_u8(skb, LWTUNNEL_IP_OPT_ERSPAN_HWID,
 807                         get_hwid(&md->u.md2))))
 808                 goto err;
 809
 810         nla_nest_end(skb, nest);
 811         return 0;
 812 err:
 813         nla_nest_cancel(skb, nest);
 814         return -ENOMEM;
 815 }
 816
 817 static int ip_tun_fill_encap_opts(struct sk_buff *skb, int type,
 818                                   struct ip_tunnel_info *tun_info)
 819 {
 820         struct nlattr *nest;
 821         int err = 0;
 822
 823         if (!(tun_info->key.tun_flags & TUNNEL_OPTIONS_PRESENT))
 824                 return 0;
 825
 826         nest = nla_nest_start_noflag(skb, type);
 827         if (!nest)
 828                 return -ENOMEM;
 829
 830         if (tun_info->key.tun_flags & TUNNEL_GENEVE_OPT)
 831                 err = ip_tun_fill_encap_opts_geneve(skb, tun_info);
 832         else if (tun_info->key.tun_flags & TUNNEL_VXLAN_OPT)
 833                 err = ip_tun_fill_encap_opts_vxlan(skb, tun_info);
 834         else if (tun_info->key.tun_flags & TUNNEL_ERSPAN_OPT)
 835                 err = ip_tun_fill_encap_opts_erspan(skb, tun_info);
 836
 837         if (err) {
 838                 nla_nest_cancel(skb, nest);
 839                 return err;
 840         }
 841
 842         nla_nest_end(skb, nest);
 843         return 0;
 844 }
 845
 846 static int ip_tun_fill_encap_info(struct sk_buff *skb,
 847                                   struct lwtunnel_state *lwtstate)
 848 {
 849         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
 850
 851         if (nla_put_be64(skb, LWTUNNEL_IP_ID, tun_info->key.tun_id,
 852                          LWTUNNEL_IP_PAD) ||
 853             nla_put_in_addr(skb, LWTUNNEL_IP_DST, tun_info->key.u.ipv4.dst) ||
 854             nla_put_in_addr(skb, LWTUNNEL_IP_SRC, tun_info->key.u.ipv4.src) ||
 855             nla_put_u8(skb, LWTUNNEL_IP_TOS, tun_info->key.tos) ||
 856             nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||
 857             nla_put_be16(skb, LWTUNNEL_IP_FLAGS, tun_info->key.tun_flags) ||
 858             ip_tun_fill_encap_opts(skb, LWTUNNEL_IP_OPTS, tun_info))
 859                 return -ENOMEM;
 860
 861         return 0;
 862 }
 863
 864 static int ip_tun_opts_nlsize(struct ip_tunnel_info *info)
 865 {
 866         int opt_len;
 867
 868         if (!(info->key.tun_flags & TUNNEL_OPTIONS_PRESENT))
 869                 return 0;
 870
 871         opt_len = nla_total_size(0);            /* LWTUNNEL_IP_OPTS */
 872         if (info->key.tun_flags & TUNNEL_GENEVE_OPT) {
 873                 struct geneve_opt *opt;
 874                 int offset = 0;
 875
 876                 opt_len += nla_total_size(0);   /* LWTUNNEL_IP_OPTS_GENEVE */
 877                 while (info->options_len > offset) {
 878                         opt = ip_tunnel_info_opts(info) + offset;
 879                         opt_len += nla_total_size(2)    /* OPT_GENEVE_CLASS */
 880                                    + nla_total_size(1)  /* OPT_GENEVE_TYPE */
 881                                    + nla_total_size(opt->length * 4);
 882                                                         /* OPT_GENEVE_DATA */
 883                         offset += sizeof(*opt) + opt->length * 4;
 884                 }
 885         } else if (info->key.tun_flags & TUNNEL_VXLAN_OPT) {
 886                 opt_len += nla_total_size(0)    /* LWTUNNEL_IP_OPTS_VXLAN */
 887                            + nla_total_size(4); /* OPT_VXLAN_GBP */
 888         } else if (info->key.tun_flags & TUNNEL_ERSPAN_OPT) {
 889                 struct erspan_metadata *md = ip_tunnel_info_opts(info);
 890
 891                 opt_len += nla_total_size(0)    /* LWTUNNEL_IP_OPTS_ERSPAN */
 892                            + nla_total_size(1)  /* OPT_ERSPAN_VER */
 893                            + (md->version == 1 ? nla_total_size(4)
 894                                                 /* OPT_ERSPAN_INDEX (v1) */
 895                                                : nla_total_size(1) +
 896                                                  nla_total_size(1));
 897                                                 /* OPT_ERSPAN_DIR + HWID (v2) */
 898         }
 899
 900         return opt_len;
 901 }
 902
 903 static int ip_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
 904 {
 905         return nla_total_size_64bit(8)  /* LWTUNNEL_IP_ID */
 906                 + nla_total_size(4)     /* LWTUNNEL_IP_DST */
 907                 + nla_total_size(4)     /* LWTUNNEL_IP_SRC */
 908                 + nla_total_size(1)     /* LWTUNNEL_IP_TOS */
 909                 + nla_total_size(1)     /* LWTUNNEL_IP_TTL */
 910                 + nla_total_size(2)     /* LWTUNNEL_IP_FLAGS */
 911                 + ip_tun_opts_nlsize(lwt_tun_info(lwtstate));
 912                                         /* LWTUNNEL_IP_OPTS */
 913 }
 914
 915 static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
 916 {
 917         struct ip_tunnel_info *info_a = lwt_tun_info(a);
 918         struct ip_tunnel_info *info_b = lwt_tun_info(b);
 919
 920         return memcmp(info_a, info_b, sizeof(info_a->key)) ||
 921                info_a->mode != info_b->mode ||
 922                info_a->options_len != info_b->options_len ||
 923                memcmp(ip_tunnel_info_opts(info_a),
 924                       ip_tunnel_info_opts(info_b), info_a->options_len);
 925 }
 926
 927 static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
 928         .build_state = ip_tun_build_state,
 929         .destroy_state = ip_tun_destroy_state,
 930         .fill_encap = ip_tun_fill_encap_info,
 931         .get_encap_size = ip_tun_encap_nlsize,
 932         .cmp_encap = ip_tun_cmp_encap,
 933         .owner = THIS_MODULE,
 934 };
 935
 936 static const struct nla_policy ip6_tun_policy[LWTUNNEL_IP6_MAX + 1] = {
 937         [LWTUNNEL_IP6_UNSPEC]   = { .strict_start_type = LWTUNNEL_IP6_OPTS },
 938         [LWTUNNEL_IP6_ID]               = { .type = NLA_U64 },
 939         [LWTUNNEL_IP6_DST]              = { .len = sizeof(struct in6_addr) },
 940         [LWTUNNEL_IP6_SRC]              = { .len = sizeof(struct in6_addr) },
 941         [LWTUNNEL_IP6_HOPLIMIT]         = { .type = NLA_U8 },
 942         [LWTUNNEL_IP6_TC]               = { .type = NLA_U8 },
 943         [LWTUNNEL_IP6_FLAGS]            = { .type = NLA_U16 },
 944         [LWTUNNEL_IP6_OPTS]             = { .type = NLA_NESTED },
 945 };
 946
 947 static int ip6_tun_build_state(struct net *net, struct nlattr *attr,
 948                                unsigned int family, const void *cfg,
 949                                struct lwtunnel_state **ts,
 950                                struct netlink_ext_ack *extack)
 951 {
 952         struct nlattr *tb[LWTUNNEL_IP6_MAX + 1];
 953         struct lwtunnel_state *new_state;
 954         struct ip_tunnel_info *tun_info;
 955         int err, opt_len;
 956
 957         err = nla_parse_nested_deprecated(tb, LWTUNNEL_IP6_MAX, attr,
 958                                           ip6_tun_policy, extack);
 959         if (err < 0)
 960                 return err;
 961
 962         opt_len = ip_tun_get_optlen(tb[LWTUNNEL_IP6_OPTS], extack);
 963         if (opt_len < 0)
 964                 return opt_len;
 965
 966         new_state = lwtunnel_state_alloc(sizeof(*tun_info) + opt_len);
 967         if (!new_state)
 968                 return -ENOMEM;
 969
 970         new_state->type = LWTUNNEL_ENCAP_IP6;
 971
 972         tun_info = lwt_tun_info(new_state);
 973
 974         err = ip_tun_set_opts(tb[LWTUNNEL_IP6_OPTS], tun_info, extack);
 975         if (err < 0) {
 976                 lwtstate_free(new_state);
 977                 return err;
 978         }
 979
 980         if (tb[LWTUNNEL_IP6_ID])
 981                 tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP6_ID]);
 982
 983         if (tb[LWTUNNEL_IP6_DST])
 984                 tun_info->key.u.ipv6.dst = nla_get_in6_addr(tb[LWTUNNEL_IP6_DST]);
 985
 986         if (tb[LWTUNNEL_IP6_SRC])
 987                 tun_info->key.u.ipv6.src = nla_get_in6_addr(tb[LWTUNNEL_IP6_SRC]);
 988
 989         if (tb[LWTUNNEL_IP6_HOPLIMIT])
 990                 tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP6_HOPLIMIT]);
 991
 992         if (tb[LWTUNNEL_IP6_TC])
 993                 tun_info->key.tos = nla_get_u8(tb[LWTUNNEL_IP6_TC]);
 994
 995         if (tb[LWTUNNEL_IP6_FLAGS])
 996                 tun_info->key.tun_flags |=
 997                                 (nla_get_be16(tb[LWTUNNEL_IP6_FLAGS]) &
 998                                  ~TUNNEL_OPTIONS_PRESENT);
 999
1000         tun_info->mode = IP_TUNNEL_INFO_TX | IP_TUNNEL_INFO_IPV6;
1001         tun_info->options_len = opt_len;
1002
1003         *ts = new_state;
1004
1005         return 0;
1006 }
1007
1008 static int ip6_tun_fill_encap_info(struct sk_buff *skb,
1009                                    struct lwtunnel_state *lwtstate)
1010 {
1011         struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
1012
1013         if (nla_put_be64(skb, LWTUNNEL_IP6_ID, tun_info->key.tun_id,
1014                          LWTUNNEL_IP6_PAD) ||
1015             nla_put_in6_addr(skb, LWTUNNEL_IP6_DST, &tun_info->key.u.ipv6.dst) ||
1016             nla_put_in6_addr(skb, LWTUNNEL_IP6_SRC, &tun_info->key.u.ipv6.src) ||
1017             nla_put_u8(skb, LWTUNNEL_IP6_TC, tun_info->key.tos) ||
1018             nla_put_u8(skb, LWTUNNEL_IP6_HOPLIMIT, tun_info->key.ttl) ||
1019             nla_put_be16(skb, LWTUNNEL_IP6_FLAGS, tun_info->key.tun_flags) ||
1020             ip_tun_fill_encap_opts(skb, LWTUNNEL_IP6_OPTS, tun_info))
1021                 return -ENOMEM;
1022
1023         return 0;
1024 }
1025
1026 static int ip6_tun_encap_nlsize(struct lwtunnel_state *lwtstate)
1027 {
1028         return nla_total_size_64bit(8)  /* LWTUNNEL_IP6_ID */
1029                 + nla_total_size(16)    /* LWTUNNEL_IP6_DST */
1030                 + nla_total_size(16)    /* LWTUNNEL_IP6_SRC */
1031                 + nla_total_size(1)     /* LWTUNNEL_IP6_HOPLIMIT */
1032                 + nla_total_size(1)     /* LWTUNNEL_IP6_TC */
1033                 + nla_total_size(2)     /* LWTUNNEL_IP6_FLAGS */
1034                 + ip_tun_opts_nlsize(lwt_tun_info(lwtstate));
1035                                         /* LWTUNNEL_IP6_OPTS */
1036 }
1037
1038 static const struct lwtunnel_encap_ops ip6_tun_lwt_ops = {
1039         .build_state = ip6_tun_build_state,
1040         .fill_encap = ip6_tun_fill_encap_info,
1041         .get_encap_size = ip6_tun_encap_nlsize,
1042         .cmp_encap = ip_tun_cmp_encap,
1043         .owner = THIS_MODULE,
1044 };
1045
1046 void __init ip_tunnel_core_init(void)
1047 {
1048         /* If you land here, make sure whether increasing ip_tunnel_info's
1049          * options_len is a reasonable choice with its usage in front ends
1050          * (f.e., it's part of flow keys, etc).
1051          */
1052         BUILD_BUG_ON(IP_TUNNEL_OPTS_MAX != 255);
1053
1054         lwtunnel_encap_add_ops(&ip_tun_lwt_ops, LWTUNNEL_ENCAP_IP);
1055         lwtunnel_encap_add_ops(&ip6_tun_lwt_ops, LWTUNNEL_ENCAP_IP6);
1056 }
1057
1058 DEFINE_STATIC_KEY_FALSE(ip_tunnel_metadata_cnt);
1059 EXPORT_SYMBOL(ip_tunnel_metadata_cnt);
1060
1061 void ip_tunnel_need_metadata(void)
1062 {
1063         static_branch_inc(&ip_tunnel_metadata_cnt);
1064 }
1065 EXPORT_SYMBOL_GPL(ip_tunnel_need_metadata);
1066
1067 void ip_tunnel_unneed_metadata(void)
1068 {
1069         static_branch_dec(&ip_tunnel_metadata_cnt);
1070 }
1071 EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata);
1072
1073 /* Returns either the correct skb->protocol value, or 0 if invalid. */
1074 __be16 ip_tunnel_parse_protocol(const struct sk_buff *skb)
1075 {
1076         if (skb_network_header(skb) >= skb->head &&
1077             (skb_network_header(skb) + sizeof(struct iphdr)) <= skb_tail_pointer(skb) &&
1078             ip_hdr(skb)->version == 4)
1079                 return htons(ETH_P_IP);
1080         if (skb_network_header(skb) >= skb->head &&
1081             (skb_network_header(skb) + sizeof(struct ipv6hdr)) <= skb_tail_pointer(skb) &&
1082             ipv6_hdr(skb)->version == 6)
1083                 return htons(ETH_P_IPV6);
1084         return 0;
1085 }
1086 EXPORT_SYMBOL(ip_tunnel_parse_protocol);
1087
1088 const struct header_ops ip_tunnel_header_ops = { .parse_protocol = ip_tunnel_parse_protocol };
1089 EXPORT_SYMBOL(ip_tunnel_header_ops);