net/openvswitch/flow.c

   1 /*
   2  * Copyright (c) 2007-2013 Nicira, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of version 2 of the GNU General Public
   6  * License as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301, USA
  17  */
  18
  19 #include "flow.h"
  20 #include "datapath.h"
  21 #include <linux/uaccess.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/etherdevice.h>
  24 #include <linux/if_ether.h>
  25 #include <linux/if_vlan.h>
  26 #include <net/llc_pdu.h>
  27 #include <linux/kernel.h>
  28 #include <linux/jhash.h>
  29 #include <linux/jiffies.h>
  30 #include <linux/llc.h>
  31 #include <linux/module.h>
  32 #include <linux/in.h>
  33 #include <linux/rcupdate.h>
  34 #include <linux/if_arp.h>
  35 #include <linux/ip.h>
  36 #include <linux/ipv6.h>
  37 #include <linux/sctp.h>
  38 #include <linux/smp.h>
  39 #include <linux/tcp.h>
  40 #include <linux/udp.h>
  41 #include <linux/icmp.h>
  42 #include <linux/icmpv6.h>
  43 #include <linux/rculist.h>
  44 #include <net/ip.h>
  45 #include <net/ip_tunnels.h>
  46 #include <net/ipv6.h>
  47 #include <net/ndisc.h>
  48
  49 u64 ovs_flow_used_time(unsigned long flow_jiffies)
  50 {
  51         struct timespec cur_ts;
  52         u64 cur_ms, idle_ms;
  53
  54         ktime_get_ts(&cur_ts);
  55         idle_ms = jiffies_to_msecs(jiffies - flow_jiffies);
  56         cur_ms = (u64)cur_ts.tv_sec * MSEC_PER_SEC +
  57                  cur_ts.tv_nsec / NSEC_PER_MSEC;
  58
  59         return cur_ms - idle_ms;
  60 }
  61
  62 #define TCP_FLAGS_BE16(tp) (*(__be16 *)&tcp_flag_word(tp) & htons(0x0FFF))
  63
  64 void ovs_flow_stats_update(struct sw_flow *flow, struct sk_buff *skb)
  65 {
  66         struct flow_stats *stats;
  67         __be16 tcp_flags = flow->key.tp.flags;
  68         int node = numa_node_id();
  69
  70         stats = rcu_dereference(flow->stats[node]);
  71
  72         /* Check if already have node-specific stats. */
  73         if (likely(stats)) {
  74                 spin_lock(&stats->lock);
  75                 /* Mark if we write on the pre-allocated stats. */
  76                 if (node == 0 && unlikely(flow->stats_last_writer != node))
  77                         flow->stats_last_writer = node;
  78         } else {
  79                 stats = rcu_dereference(flow->stats[0]); /* Pre-allocated. */
  80                 spin_lock(&stats->lock);
  81
  82                 /* If the current NUMA-node is the only writer on the
  83                  * pre-allocated stats keep using them.
  84                  */
  85                 if (unlikely(flow->stats_last_writer != node)) {
  86                         /* A previous locker may have already allocated the
  87                          * stats, so we need to check again.  If node-specific
  88                          * stats were already allocated, we update the pre-
  89                          * allocated stats as we have already locked them.
  90                          */
  91                         if (likely(flow->stats_last_writer != NUMA_NO_NODE)
  92                             && likely(!rcu_dereference(flow->stats[node]))) {
  93                                 /* Try to allocate node-specific stats. */
  94                                 struct flow_stats *new_stats;
  95
  96                                 new_stats =
  97                                         kmem_cache_alloc_node(flow_stats_cache,
  98                                                               GFP_THISNODE |
  99                                                               __GFP_NOMEMALLOC,
 100                                                               node);
 101                                 if (likely(new_stats)) {
 102                                         new_stats->used = jiffies;
 103                                         new_stats->packet_count = 1;
 104                                         new_stats->byte_count = skb->len;
 105                                         new_stats->tcp_flags = tcp_flags;
 106                                         spin_lock_init(&new_stats->lock);
 107
 108                                         rcu_assign_pointer(flow->stats[node],
 109                                                            new_stats);
 110                                         goto unlock;
 111                                 }
 112                         }
 113                         flow->stats_last_writer = node;
 114                 }
 115         }
 116
 117         stats->used = jiffies;
 118         stats->packet_count++;
 119         stats->byte_count += skb->len;
 120         stats->tcp_flags |= tcp_flags;
 121 unlock:
 122         spin_unlock(&stats->lock);
 123 }
 124
 125 void ovs_flow_stats_get(struct sw_flow *flow, struct ovs_flow_stats *ovs_stats,
 126                         unsigned long *used, __be16 *tcp_flags)
 127 {
 128         int node;
 129
 130         *used = 0;
 131         *tcp_flags = 0;
 132         memset(ovs_stats, 0, sizeof(*ovs_stats));
 133
 134         for_each_node(node) {
 135                 struct flow_stats *stats = rcu_dereference(flow->stats[node]);
 136
 137                 if (stats) {
 138                         /* Local CPU may write on non-local stats, so we must
 139                          * block bottom-halves here.
 140                          */
 141                         spin_lock_bh(&stats->lock);
 142                         if (!*used || time_after(stats->used, *used))
 143                                 *used = stats->used;
 144                         *tcp_flags |= stats->tcp_flags;
 145                         ovs_stats->n_packets += stats->packet_count;
 146                         ovs_stats->n_bytes += stats->byte_count;
 147                         spin_unlock_bh(&stats->lock);
 148                 }
 149         }
 150 }
 151
 152 void ovs_flow_stats_clear(struct sw_flow *flow)
 153 {
 154         int node;
 155
 156         for_each_node(node) {
 157                 struct flow_stats *stats = rcu_dereference(flow->stats[node]);
 158
 159                 if (stats) {
 160                         spin_lock_bh(&stats->lock);
 161                         stats->used = 0;
 162                         stats->packet_count = 0;
 163                         stats->byte_count = 0;
 164                         stats->tcp_flags = 0;
 165                         spin_unlock_bh(&stats->lock);
 166                 }
 167         }
 168 }
 169
 170 static int check_header(struct sk_buff *skb, int len)
 171 {
 172         if (unlikely(skb->len < len))
 173                 return -EINVAL;
 174         if (unlikely(!pskb_may_pull(skb, len)))
 175                 return -ENOMEM;
 176         return 0;
 177 }
 178
 179 static bool arphdr_ok(struct sk_buff *skb)
 180 {
 181         return pskb_may_pull(skb, skb_network_offset(skb) +
 182                                   sizeof(struct arp_eth_header));
 183 }
 184
 185 static int check_iphdr(struct sk_buff *skb)
 186 {
 187         unsigned int nh_ofs = skb_network_offset(skb);
 188         unsigned int ip_len;
 189         int err;
 190
 191         err = check_header(skb, nh_ofs + sizeof(struct iphdr));
 192         if (unlikely(err))
 193                 return err;
 194
 195         ip_len = ip_hdrlen(skb);
 196         if (unlikely(ip_len < sizeof(struct iphdr) ||
 197                      skb->len < nh_ofs + ip_len))
 198                 return -EINVAL;
 199
 200         skb_set_transport_header(skb, nh_ofs + ip_len);
 201         return 0;
 202 }
 203
 204 static bool tcphdr_ok(struct sk_buff *skb)
 205 {
 206         int th_ofs = skb_transport_offset(skb);
 207         int tcp_len;
 208
 209         if (unlikely(!pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))))
 210                 return false;
 211
 212         tcp_len = tcp_hdrlen(skb);
 213         if (unlikely(tcp_len < sizeof(struct tcphdr) ||
 214                      skb->len < th_ofs + tcp_len))
 215                 return false;
 216
 217         return true;
 218 }
 219
 220 static bool udphdr_ok(struct sk_buff *skb)
 221 {
 222         return pskb_may_pull(skb, skb_transport_offset(skb) +
 223                                   sizeof(struct udphdr));
 224 }
 225
 226 static bool sctphdr_ok(struct sk_buff *skb)
 227 {
 228         return pskb_may_pull(skb, skb_transport_offset(skb) +
 229                                   sizeof(struct sctphdr));
 230 }
 231
 232 static bool icmphdr_ok(struct sk_buff *skb)
 233 {
 234         return pskb_may_pull(skb, skb_transport_offset(skb) +
 235                                   sizeof(struct icmphdr));
 236 }
 237
 238 static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key)
 239 {
 240         unsigned int nh_ofs = skb_network_offset(skb);
 241         unsigned int nh_len;
 242         int payload_ofs;
 243         struct ipv6hdr *nh;
 244         uint8_t nexthdr;
 245         __be16 frag_off;
 246         int err;
 247
 248         err = check_header(skb, nh_ofs + sizeof(*nh));
 249         if (unlikely(err))
 250                 return err;
 251
 252         nh = ipv6_hdr(skb);
 253         nexthdr = nh->nexthdr;
 254         payload_ofs = (u8 *)(nh + 1) - skb->data;
 255
 256         key->ip.proto = NEXTHDR_NONE;
 257         key->ip.tos = ipv6_get_dsfield(nh);
 258         key->ip.ttl = nh->hop_limit;
 259         key->ipv6.label = *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
 260         key->ipv6.addr.src = nh->saddr;
 261         key->ipv6.addr.dst = nh->daddr;
 262
 263         payload_ofs = ipv6_skip_exthdr(skb, payload_ofs, &nexthdr, &frag_off);
 264         if (unlikely(payload_ofs < 0))
 265                 return -EINVAL;
 266
 267         if (frag_off) {
 268                 if (frag_off & htons(~0x7))
 269                         key->ip.frag = OVS_FRAG_TYPE_LATER;
 270                 else
 271                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 272         }
 273
 274         nh_len = payload_ofs - nh_ofs;
 275         skb_set_transport_header(skb, nh_ofs + nh_len);
 276         key->ip.proto = nexthdr;
 277         return nh_len;
 278 }
 279
 280 static bool icmp6hdr_ok(struct sk_buff *skb)
 281 {
 282         return pskb_may_pull(skb, skb_transport_offset(skb) +
 283                                   sizeof(struct icmp6hdr));
 284 }
 285
 286 static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
 287 {
 288         struct qtag_prefix {
 289                 __be16 eth_type; /* ETH_P_8021Q */
 290                 __be16 tci;
 291         };
 292         struct qtag_prefix *qp;
 293
 294         if (unlikely(skb->len < sizeof(struct qtag_prefix) + sizeof(__be16)))
 295                 return 0;
 296
 297         if (unlikely(!pskb_may_pull(skb, sizeof(struct qtag_prefix) +
 298                                          sizeof(__be16))))
 299                 return -ENOMEM;
 300
 301         qp = (struct qtag_prefix *) skb->data;
 302         key->eth.tci = qp->tci | htons(VLAN_TAG_PRESENT);
 303         __skb_pull(skb, sizeof(struct qtag_prefix));
 304
 305         return 0;
 306 }
 307
 308 static __be16 parse_ethertype(struct sk_buff *skb)
 309 {
 310         struct llc_snap_hdr {
 311                 u8  dsap;  /* Always 0xAA */
 312                 u8  ssap;  /* Always 0xAA */
 313                 u8  ctrl;
 314                 u8  oui[3];
 315                 __be16 ethertype;
 316         };
 317         struct llc_snap_hdr *llc;
 318         __be16 proto;
 319
 320         proto = *(__be16 *) skb->data;
 321         __skb_pull(skb, sizeof(__be16));
 322
 323         if (ntohs(proto) >= ETH_P_802_3_MIN)
 324                 return proto;
 325
 326         if (skb->len < sizeof(struct llc_snap_hdr))
 327                 return htons(ETH_P_802_2);
 328
 329         if (unlikely(!pskb_may_pull(skb, sizeof(struct llc_snap_hdr))))
 330                 return htons(0);
 331
 332         llc = (struct llc_snap_hdr *) skb->data;
 333         if (llc->dsap != LLC_SAP_SNAP ||
 334             llc->ssap != LLC_SAP_SNAP ||
 335             (llc->oui[0] | llc->oui[1] | llc->oui[2]) != 0)
 336                 return htons(ETH_P_802_2);
 337
 338         __skb_pull(skb, sizeof(struct llc_snap_hdr));
 339
 340         if (ntohs(llc->ethertype) >= ETH_P_802_3_MIN)
 341                 return llc->ethertype;
 342
 343         return htons(ETH_P_802_2);
 344 }
 345
 346 static int parse_icmpv6(struct sk_buff *skb, struct sw_flow_key *key,
 347                         int nh_len)
 348 {
 349         struct icmp6hdr *icmp = icmp6_hdr(skb);
 350
 351         /* The ICMPv6 type and code fields use the 16-bit transport port
 352          * fields, so we need to store them in 16-bit network byte order.
 353          */
 354         key->tp.src = htons(icmp->icmp6_type);
 355         key->tp.dst = htons(icmp->icmp6_code);
 356
 357         if (icmp->icmp6_code == 0 &&
 358             (icmp->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION ||
 359              icmp->icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT)) {
 360                 int icmp_len = skb->len - skb_transport_offset(skb);
 361                 struct nd_msg *nd;
 362                 int offset;
 363
 364                 /* In order to process neighbor discovery options, we need the
 365                  * entire packet.
 366                  */
 367                 if (unlikely(icmp_len < sizeof(*nd)))
 368                         return 0;
 369
 370                 if (unlikely(skb_linearize(skb)))
 371                         return -ENOMEM;
 372
 373                 nd = (struct nd_msg *)skb_transport_header(skb);
 374                 key->ipv6.nd.target = nd->target;
 375
 376                 icmp_len -= sizeof(*nd);
 377                 offset = 0;
 378                 while (icmp_len >= 8) {
 379                         struct nd_opt_hdr *nd_opt =
 380                                  (struct nd_opt_hdr *)(nd->opt + offset);
 381                         int opt_len = nd_opt->nd_opt_len * 8;
 382
 383                         if (unlikely(!opt_len || opt_len > icmp_len))
 384                                 return 0;
 385
 386                         /* Store the link layer address if the appropriate
 387                          * option is provided.  It is considered an error if
 388                          * the same link layer option is specified twice.
 389                          */
 390                         if (nd_opt->nd_opt_type == ND_OPT_SOURCE_LL_ADDR
 391                             && opt_len == 8) {
 392                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.sll)))
 393                                         goto invalid;
 394                                 ether_addr_copy(key->ipv6.nd.sll,
 395                                                 &nd->opt[offset+sizeof(*nd_opt)]);
 396                         } else if (nd_opt->nd_opt_type == ND_OPT_TARGET_LL_ADDR
 397                                    && opt_len == 8) {
 398                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.tll)))
 399                                         goto invalid;
 400                                 ether_addr_copy(key->ipv6.nd.tll,
 401                                                 &nd->opt[offset+sizeof(*nd_opt)]);
 402                         }
 403
 404                         icmp_len -= opt_len;
 405                         offset += opt_len;
 406                 }
 407         }
 408
 409         return 0;
 410
 411 invalid:
 412         memset(&key->ipv6.nd.target, 0, sizeof(key->ipv6.nd.target));
 413         memset(key->ipv6.nd.sll, 0, sizeof(key->ipv6.nd.sll));
 414         memset(key->ipv6.nd.tll, 0, sizeof(key->ipv6.nd.tll));
 415
 416         return 0;
 417 }
 418
 419 /**
 420  * ovs_flow_extract - extracts a flow key from an Ethernet frame.
 421  * @skb: sk_buff that contains the frame, with skb->data pointing to the
 422  * Ethernet header
 423  * @in_port: port number on which @skb was received.
 424  * @key: output flow key
 425  *
 426  * The caller must ensure that skb->len >= ETH_HLEN.
 427  *
 428  * Returns 0 if successful, otherwise a negative errno value.
 429  *
 430  * Initializes @skb header pointers as follows:
 431  *
 432  *    - skb->mac_header: the Ethernet header.
 433  *
 434  *    - skb->network_header: just past the Ethernet header, or just past the
 435  *      VLAN header, to the first byte of the Ethernet payload.
 436  *
 437  *    - skb->transport_header: If key->eth.type is ETH_P_IP or ETH_P_IPV6
 438  *      on output, then just past the IP header, if one is present and
 439  *      of a correct length, otherwise the same as skb->network_header.
 440  *      For other key->eth.type values it is left untouched.
 441  */
 442 int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
 443 {
 444         int error;
 445         struct ethhdr *eth;
 446
 447         memset(key, 0, sizeof(*key));
 448
 449         key->phy.priority = skb->priority;
 450         if (OVS_CB(skb)->tun_key)
 451                 memcpy(&key->tun_key, OVS_CB(skb)->tun_key, sizeof(key->tun_key));
 452         key->phy.in_port = in_port;
 453         key->phy.skb_mark = skb->mark;
 454
 455         skb_reset_mac_header(skb);
 456
 457         /* Link layer.  We are guaranteed to have at least the 14 byte Ethernet
 458          * header in the linear data area.
 459          */
 460         eth = eth_hdr(skb);
 461         ether_addr_copy(key->eth.src, eth->h_source);
 462         ether_addr_copy(key->eth.dst, eth->h_dest);
 463
 464         __skb_pull(skb, 2 * ETH_ALEN);
 465         /* We are going to push all headers that we pull, so no need to
 466          * update skb->csum here.
 467          */
 468
 469         if (vlan_tx_tag_present(skb))
 470                 key->eth.tci = htons(skb->vlan_tci);
 471         else if (eth->h_proto == htons(ETH_P_8021Q))
 472                 if (unlikely(parse_vlan(skb, key)))
 473                         return -ENOMEM;
 474
 475         key->eth.type = parse_ethertype(skb);
 476         if (unlikely(key->eth.type == htons(0)))
 477                 return -ENOMEM;
 478
 479         skb_reset_network_header(skb);
 480         __skb_push(skb, skb->data - skb_mac_header(skb));
 481
 482         /* Network layer. */
 483         if (key->eth.type == htons(ETH_P_IP)) {
 484                 struct iphdr *nh;
 485                 __be16 offset;
 486
 487                 error = check_iphdr(skb);
 488                 if (unlikely(error)) {
 489                         if (error == -EINVAL) {
 490                                 skb->transport_header = skb->network_header;
 491                                 error = 0;
 492                         }
 493                         return error;
 494                 }
 495
 496                 nh = ip_hdr(skb);
 497                 key->ipv4.addr.src = nh->saddr;
 498                 key->ipv4.addr.dst = nh->daddr;
 499
 500                 key->ip.proto = nh->protocol;
 501                 key->ip.tos = nh->tos;
 502                 key->ip.ttl = nh->ttl;
 503
 504                 offset = nh->frag_off & htons(IP_OFFSET);
 505                 if (offset) {
 506                         key->ip.frag = OVS_FRAG_TYPE_LATER;
 507                         return 0;
 508                 }
 509                 if (nh->frag_off & htons(IP_MF) ||
 510                          skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 511                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 512
 513                 /* Transport layer. */
 514                 if (key->ip.proto == IPPROTO_TCP) {
 515                         if (tcphdr_ok(skb)) {
 516                                 struct tcphdr *tcp = tcp_hdr(skb);
 517                                 key->tp.src = tcp->source;
 518                                 key->tp.dst = tcp->dest;
 519                                 key->tp.flags = TCP_FLAGS_BE16(tcp);
 520                         }
 521                 } else if (key->ip.proto == IPPROTO_UDP) {
 522                         if (udphdr_ok(skb)) {
 523                                 struct udphdr *udp = udp_hdr(skb);
 524                                 key->tp.src = udp->source;
 525                                 key->tp.dst = udp->dest;
 526                         }
 527                 } else if (key->ip.proto == IPPROTO_SCTP) {
 528                         if (sctphdr_ok(skb)) {
 529                                 struct sctphdr *sctp = sctp_hdr(skb);
 530                                 key->tp.src = sctp->source;
 531                                 key->tp.dst = sctp->dest;
 532                         }
 533                 } else if (key->ip.proto == IPPROTO_ICMP) {
 534                         if (icmphdr_ok(skb)) {
 535                                 struct icmphdr *icmp = icmp_hdr(skb);
 536                                 /* The ICMP type and code fields use the 16-bit
 537                                  * transport port fields, so we need to store
 538                                  * them in 16-bit network byte order. */
 539                                 key->tp.src = htons(icmp->type);
 540                                 key->tp.dst = htons(icmp->code);
 541                         }
 542                 }
 543
 544         } else if ((key->eth.type == htons(ETH_P_ARP) ||
 545                    key->eth.type == htons(ETH_P_RARP)) && arphdr_ok(skb)) {
 546                 struct arp_eth_header *arp;
 547
 548                 arp = (struct arp_eth_header *)skb_network_header(skb);
 549
 550                 if (arp->ar_hrd == htons(ARPHRD_ETHER)
 551                                 && arp->ar_pro == htons(ETH_P_IP)
 552                                 && arp->ar_hln == ETH_ALEN
 553                                 && arp->ar_pln == 4) {
 554
 555                         /* We only match on the lower 8 bits of the opcode. */
 556                         if (ntohs(arp->ar_op) <= 0xff)
 557                                 key->ip.proto = ntohs(arp->ar_op);
 558                         memcpy(&key->ipv4.addr.src, arp->ar_sip, sizeof(key->ipv4.addr.src));
 559                         memcpy(&key->ipv4.addr.dst, arp->ar_tip, sizeof(key->ipv4.addr.dst));
 560                         ether_addr_copy(key->ipv4.arp.sha, arp->ar_sha);
 561                         ether_addr_copy(key->ipv4.arp.tha, arp->ar_tha);
 562                 }
 563         } else if (key->eth.type == htons(ETH_P_IPV6)) {
 564                 int nh_len;             /* IPv6 Header + Extensions */
 565
 566                 nh_len = parse_ipv6hdr(skb, key);
 567                 if (unlikely(nh_len < 0)) {
 568                         if (nh_len == -EINVAL) {
 569                                 skb->transport_header = skb->network_header;
 570                                 error = 0;
 571                         } else {
 572                                 error = nh_len;
 573                         }
 574                         return error;
 575                 }
 576
 577                 if (key->ip.frag == OVS_FRAG_TYPE_LATER)
 578                         return 0;
 579                 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 580                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 581
 582                 /* Transport layer. */
 583                 if (key->ip.proto == NEXTHDR_TCP) {
 584                         if (tcphdr_ok(skb)) {
 585                                 struct tcphdr *tcp = tcp_hdr(skb);
 586                                 key->tp.src = tcp->source;
 587                                 key->tp.dst = tcp->dest;
 588                                 key->tp.flags = TCP_FLAGS_BE16(tcp);
 589                         }
 590                 } else if (key->ip.proto == NEXTHDR_UDP) {
 591                         if (udphdr_ok(skb)) {
 592                                 struct udphdr *udp = udp_hdr(skb);
 593                                 key->tp.src = udp->source;
 594                                 key->tp.dst = udp->dest;
 595                         }
 596                 } else if (key->ip.proto == NEXTHDR_SCTP) {
 597                         if (sctphdr_ok(skb)) {
 598                                 struct sctphdr *sctp = sctp_hdr(skb);
 599                                 key->tp.src = sctp->source;
 600                                 key->tp.dst = sctp->dest;
 601                         }
 602                 } else if (key->ip.proto == NEXTHDR_ICMP) {
 603                         if (icmp6hdr_ok(skb)) {
 604                                 error = parse_icmpv6(skb, key, nh_len);
 605                                 if (error)
 606                                         return error;
 607                         }
 608                 }
 609         }
 610
 611         return 0;
 612 }