datapath/flow.c

   1 /*
   2  * Copyright (c) 2007-2014 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/ipv6.h>
  46 #include <net/ndisc.h>
  47
  48 #include "vlan.h"
  49
  50 u64 ovs_flow_used_time(unsigned long flow_jiffies)
  51 {
  52         struct timespec cur_ts;
  53         u64 cur_ms, idle_ms;
  54
  55         ktime_get_ts(&cur_ts);
  56         idle_ms = jiffies_to_msecs(jiffies - flow_jiffies);
  57         cur_ms = (u64)cur_ts.tv_sec * MSEC_PER_SEC +
  58                  cur_ts.tv_nsec / NSEC_PER_MSEC;
  59
  60         return cur_ms - idle_ms;
  61 }
  62
  63 #define TCP_FLAGS_BE16(tp) (*(__be16 *)&tcp_flag_word(tp) & htons(0x0FFF))
  64
  65 void ovs_flow_stats_update(struct sw_flow *flow, struct sk_buff *skb)
  66 {
  67         struct flow_stats *stats;
  68         __be16 tcp_flags = flow->key.tp.flags;
  69         int node = numa_node_id();
  70
  71         stats = rcu_dereference(flow->stats[node]);
  72
  73         /* Check if already have node-specific stats. */
  74         if (likely(stats)) {
  75                 spin_lock(&stats->lock);
  76                 /* Mark if we write on the pre-allocated stats. */
  77                 if (node == 0 && unlikely(flow->stats_last_writer != node))
  78                         flow->stats_last_writer = node;
  79         } else {
  80                 stats = rcu_dereference(flow->stats[0]); /* Pre-allocated. */
  81                 spin_lock(&stats->lock);
  82
  83                 /* If the current NUMA-node is the only writer on the
  84                  * pre-allocated stats keep using them.
  85                  */
  86                 if (unlikely(flow->stats_last_writer != node)) {
  87                         /* A previous locker may have already allocated the
  88                          * stats, so we need to check again.  If node-specific
  89                          * stats were already allocated, we update the pre-
  90                          * allocated stats as we have already locked them.
  91                          */
  92                         if (likely(flow->stats_last_writer != NUMA_NO_NODE)
  93                             && likely(!rcu_dereference(flow->stats[node]))) {
  94                                 /* Try to allocate node-specific stats. */
  95                                 struct flow_stats *new_stats;
  96
  97                                 new_stats =
  98                                         kmem_cache_alloc_node(flow_stats_cache,
  99                                                               GFP_THISNODE |
 100                                                               __GFP_NOMEMALLOC,
 101                                                               node);
 102                                 if (likely(new_stats)) {
 103                                         new_stats->used = jiffies;
 104                                         new_stats->packet_count = 1;
 105                                         new_stats->byte_count = skb->len;
 106                                         new_stats->tcp_flags = tcp_flags;
 107                                         spin_lock_init(&new_stats->lock);
 108
 109                                         rcu_assign_pointer(flow->stats[node],
 110                                                            new_stats);
 111                                         goto unlock;
 112                                 }
 113                         }
 114                         flow->stats_last_writer = node;
 115                 }
 116         }
 117
 118         stats->used = jiffies;
 119         stats->packet_count++;
 120         stats->byte_count += skb->len;
 121         stats->tcp_flags |= tcp_flags;
 122 unlock:
 123         spin_unlock(&stats->lock);
 124 }
 125
 126 /* Called with ovs_mutex. */
 127 void ovs_flow_stats_get(struct sw_flow *flow, struct ovs_flow_stats *ovs_stats,
 128                         unsigned long *used, __be16 *tcp_flags)
 129 {
 130         int node;
 131
 132         *used = 0;
 133         *tcp_flags = 0;
 134         memset(ovs_stats, 0, sizeof(*ovs_stats));
 135
 136         for_each_node(node) {
 137                 struct flow_stats *stats = ovsl_dereference(flow->stats[node]);
 138
 139                 if (stats) {
 140                         /* Local CPU may write on non-local stats, so we must
 141                          * block bottom-halves here.
 142                          */
 143                         spin_lock_bh(&stats->lock);
 144                         if (!*used || time_after(stats->used, *used))
 145                                 *used = stats->used;
 146                         *tcp_flags |= stats->tcp_flags;
 147                         ovs_stats->n_packets += stats->packet_count;
 148                         ovs_stats->n_bytes += stats->byte_count;
 149                         spin_unlock_bh(&stats->lock);
 150                 }
 151         }
 152 }
 153
 154 void ovs_flow_stats_clear(struct sw_flow *flow)
 155 {
 156         int node;
 157
 158         for_each_node(node) {
 159                 struct flow_stats *stats = rcu_dereference(flow->stats[node]);
 160
 161                 if (stats) {
 162                         spin_lock_bh(&stats->lock);
 163                         stats->used = 0;
 164                         stats->packet_count = 0;
 165                         stats->byte_count = 0;
 166                         stats->tcp_flags = 0;
 167                         spin_unlock_bh(&stats->lock);
 168                 }
 169         }
 170 }
 171
 172 static int check_header(struct sk_buff *skb, int len)
 173 {
 174         if (unlikely(skb->len < len))
 175                 return -EINVAL;
 176         if (unlikely(!pskb_may_pull(skb, len)))
 177                 return -ENOMEM;
 178         return 0;
 179 }
 180
 181 static bool arphdr_ok(struct sk_buff *skb)
 182 {
 183         return pskb_may_pull(skb, skb_network_offset(skb) +
 184                                   sizeof(struct arp_eth_header));
 185 }
 186
 187 static int check_iphdr(struct sk_buff *skb)
 188 {
 189         unsigned int nh_ofs = skb_network_offset(skb);
 190         unsigned int ip_len;
 191         int err;
 192
 193         err = check_header(skb, nh_ofs + sizeof(struct iphdr));
 194         if (unlikely(err))
 195                 return err;
 196
 197         ip_len = ip_hdrlen(skb);
 198         if (unlikely(ip_len < sizeof(struct iphdr) ||
 199                      skb->len < nh_ofs + ip_len))
 200                 return -EINVAL;
 201
 202         skb_set_transport_header(skb, nh_ofs + ip_len);
 203         return 0;
 204 }
 205
 206 static bool tcphdr_ok(struct sk_buff *skb)
 207 {
 208         int th_ofs = skb_transport_offset(skb);
 209         int tcp_len;
 210
 211         if (unlikely(!pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))))
 212                 return false;
 213
 214         tcp_len = tcp_hdrlen(skb);
 215         if (unlikely(tcp_len < sizeof(struct tcphdr) ||
 216                      skb->len < th_ofs + tcp_len))
 217                 return false;
 218
 219         return true;
 220 }
 221
 222 static bool udphdr_ok(struct sk_buff *skb)
 223 {
 224         return pskb_may_pull(skb, skb_transport_offset(skb) +
 225                                   sizeof(struct udphdr));
 226 }
 227
 228 static bool sctphdr_ok(struct sk_buff *skb)
 229 {
 230         return pskb_may_pull(skb, skb_transport_offset(skb) +
 231                                   sizeof(struct sctphdr));
 232 }
 233
 234 static bool icmphdr_ok(struct sk_buff *skb)
 235 {
 236         return pskb_may_pull(skb, skb_transport_offset(skb) +
 237                                   sizeof(struct icmphdr));
 238 }
 239
 240 static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key)
 241 {
 242         unsigned int nh_ofs = skb_network_offset(skb);
 243         unsigned int nh_len;
 244         int payload_ofs;
 245         struct ipv6hdr *nh;
 246         uint8_t nexthdr;
 247         __be16 frag_off;
 248         int err;
 249
 250         err = check_header(skb, nh_ofs + sizeof(*nh));
 251         if (unlikely(err))
 252                 return err;
 253
 254         nh = ipv6_hdr(skb);
 255         nexthdr = nh->nexthdr;
 256         payload_ofs = (u8 *)(nh + 1) - skb->data;
 257
 258         key->ip.proto = NEXTHDR_NONE;
 259         key->ip.tos = ipv6_get_dsfield(nh);
 260         key->ip.ttl = nh->hop_limit;
 261         key->ipv6.label = *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
 262         key->ipv6.addr.src = nh->saddr;
 263         key->ipv6.addr.dst = nh->daddr;
 264
 265         payload_ofs = ipv6_skip_exthdr(skb, payload_ofs, &nexthdr, &frag_off);
 266         if (unlikely(payload_ofs < 0))
 267                 return -EINVAL;
 268
 269         if (frag_off) {
 270                 if (frag_off & htons(~0x7))
 271                         key->ip.frag = OVS_FRAG_TYPE_LATER;
 272                 else
 273                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 274         }
 275
 276         nh_len = payload_ofs - nh_ofs;
 277         skb_set_transport_header(skb, nh_ofs + nh_len);
 278         key->ip.proto = nexthdr;
 279         return nh_len;
 280 }
 281
 282 static bool icmp6hdr_ok(struct sk_buff *skb)
 283 {
 284         return pskb_may_pull(skb, skb_transport_offset(skb) +
 285                                   sizeof(struct icmp6hdr));
 286 }
 287
 288 static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
 289 {
 290         struct qtag_prefix {
 291                 __be16 eth_type; /* ETH_P_8021Q */
 292                 __be16 tci;
 293         };
 294         struct qtag_prefix *qp;
 295
 296         if (unlikely(skb->len < sizeof(struct qtag_prefix) + sizeof(__be16)))
 297                 return 0;
 298
 299         if (unlikely(!pskb_may_pull(skb, sizeof(struct qtag_prefix) +
 300                                          sizeof(__be16))))
 301                 return -ENOMEM;
 302
 303         qp = (struct qtag_prefix *) skb->data;
 304         key->eth.tci = qp->tci | htons(VLAN_TAG_PRESENT);
 305         __skb_pull(skb, sizeof(struct qtag_prefix));
 306
 307         return 0;
 308 }
 309
 310 static __be16 parse_ethertype(struct sk_buff *skb)
 311 {
 312         struct llc_snap_hdr {
 313                 u8  dsap;  /* Always 0xAA */
 314                 u8  ssap;  /* Always 0xAA */
 315                 u8  ctrl;
 316                 u8  oui[3];
 317                 __be16 ethertype;
 318         };
 319         struct llc_snap_hdr *llc;
 320         __be16 proto;
 321
 322         proto = *(__be16 *) skb->data;
 323         __skb_pull(skb, sizeof(__be16));
 324
 325         if (ntohs(proto) >= ETH_P_802_3_MIN)
 326                 return proto;
 327
 328         if (skb->len < sizeof(struct llc_snap_hdr))
 329                 return htons(ETH_P_802_2);
 330
 331         if (unlikely(!pskb_may_pull(skb, sizeof(struct llc_snap_hdr))))
 332                 return htons(0);
 333
 334         llc = (struct llc_snap_hdr *) skb->data;
 335         if (llc->dsap != LLC_SAP_SNAP ||
 336             llc->ssap != LLC_SAP_SNAP ||
 337             (llc->oui[0] | llc->oui[1] | llc->oui[2]) != 0)
 338                 return htons(ETH_P_802_2);
 339
 340         __skb_pull(skb, sizeof(struct llc_snap_hdr));
 341
 342         if (ntohs(llc->ethertype) >= ETH_P_802_3_MIN)
 343                 return llc->ethertype;
 344
 345         return htons(ETH_P_802_2);
 346 }
 347
 348 static int parse_icmpv6(struct sk_buff *skb, struct sw_flow_key *key,
 349                         int nh_len)
 350 {
 351         struct icmp6hdr *icmp = icmp6_hdr(skb);
 352
 353         /* The ICMPv6 type and code fields use the 16-bit transport port
 354          * fields, so we need to store them in 16-bit network byte order.
 355          */
 356         key->tp.src = htons(icmp->icmp6_type);
 357         key->tp.dst = htons(icmp->icmp6_code);
 358
 359         if (icmp->icmp6_code == 0 &&
 360             (icmp->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION ||
 361              icmp->icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT)) {
 362                 int icmp_len = skb->len - skb_transport_offset(skb);
 363                 struct nd_msg *nd;
 364                 int offset;
 365
 366                 /* In order to process neighbor discovery options, we need the
 367                  * entire packet.
 368                  */
 369                 if (unlikely(icmp_len < sizeof(*nd)))
 370                         return 0;
 371
 372                 if (unlikely(skb_linearize(skb)))
 373                         return -ENOMEM;
 374
 375                 nd = (struct nd_msg *)skb_transport_header(skb);
 376                 key->ipv6.nd.target = nd->target;
 377
 378                 icmp_len -= sizeof(*nd);
 379                 offset = 0;
 380                 while (icmp_len >= 8) {
 381                         struct nd_opt_hdr *nd_opt =
 382                                  (struct nd_opt_hdr *)(nd->opt + offset);
 383                         int opt_len = nd_opt->nd_opt_len * 8;
 384
 385                         if (unlikely(!opt_len || opt_len > icmp_len))
 386                                 return 0;
 387
 388                         /* Store the link layer address if the appropriate
 389                          * option is provided.  It is considered an error if
 390                          * the same link layer option is specified twice.
 391                          */
 392                         if (nd_opt->nd_opt_type == ND_OPT_SOURCE_LL_ADDR
 393                             && opt_len == 8) {
 394                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.sll)))
 395                                         goto invalid;
 396                                 ether_addr_copy(key->ipv6.nd.sll,
 397                                     &nd->opt[offset+sizeof(*nd_opt)]);
 398                         } else if (nd_opt->nd_opt_type == ND_OPT_TARGET_LL_ADDR
 399                                    && opt_len == 8) {
 400                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.tll)))
 401                                         goto invalid;
 402                                 ether_addr_copy(key->ipv6.nd.tll,
 403                                     &nd->opt[offset+sizeof(*nd_opt)]);
 404                         }
 405
 406                         icmp_len -= opt_len;
 407                         offset += opt_len;
 408                 }
 409         }
 410
 411         return 0;
 412
 413 invalid:
 414         memset(&key->ipv6.nd.target, 0, sizeof(key->ipv6.nd.target));
 415         memset(key->ipv6.nd.sll, 0, sizeof(key->ipv6.nd.sll));
 416         memset(key->ipv6.nd.tll, 0, sizeof(key->ipv6.nd.tll));
 417
 418         return 0;
 419 }
 420
 421 /**
 422  * ovs_flow_extract - extracts a flow key from an Ethernet frame.
 423  * @skb: sk_buff that contains the frame, with skb->data pointing to the
 424  * Ethernet header
 425  * @in_port: port number on which @skb was received.
 426  * @key: output flow key
 427  *
 428  * The caller must ensure that skb->len >= ETH_HLEN.
 429  *
 430  * Returns 0 if successful, otherwise a negative errno value.
 431  *
 432  * Initializes @skb header pointers as follows:
 433  *
 434  *    - skb->mac_header: the Ethernet header.
 435  *
 436  *    - skb->network_header: just past the Ethernet header, or just past the
 437  *      VLAN header, to the first byte of the Ethernet payload.
 438  *
 439  *    - skb->transport_header: If key->eth.type is ETH_P_IP or ETH_P_IPV6
 440  *      on output, then just past the IP header, if one is present and
 441  *      of a correct length, otherwise the same as skb->network_header.
 442  *      For other key->eth.type values it is left untouched.
 443  */
 444 int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
 445 {
 446         int error;
 447         struct ethhdr *eth;
 448
 449         memset(key, 0, sizeof(*key));
 450
 451         key->phy.priority = skb->priority;
 452         if (OVS_CB(skb)->tun_key)
 453                 memcpy(&key->tun_key, OVS_CB(skb)->tun_key, sizeof(key->tun_key));
 454         key->phy.in_port = in_port;
 455         key->phy.skb_mark = skb->mark;
 456
 457         skb_reset_mac_header(skb);
 458
 459         /* Link layer.  We are guaranteed to have at least the 14 byte Ethernet
 460          * header in the linear data area.
 461          */
 462         eth = eth_hdr(skb);
 463         ether_addr_copy(key->eth.src, eth->h_source);
 464         ether_addr_copy(key->eth.dst, eth->h_dest);
 465
 466         __skb_pull(skb, 2 * ETH_ALEN);
 467         /* We are going to push all headers that we pull, so no need to
 468          * update skb->csum here. */
 469
 470         if (vlan_tx_tag_present(skb))
 471                 key->eth.tci = htons(vlan_get_tci(skb));
 472         else if (eth->h_proto == htons(ETH_P_8021Q))
 473                 if (unlikely(parse_vlan(skb, key)))
 474                         return -ENOMEM;
 475
 476         key->eth.type = parse_ethertype(skb);
 477         if (unlikely(key->eth.type == htons(0)))
 478                 return -ENOMEM;
 479
 480         skb_reset_network_header(skb);
 481         __skb_push(skb, skb->data - skb_mac_header(skb));
 482
 483         /* Network layer. */
 484         if (key->eth.type == htons(ETH_P_IP)) {
 485                 struct iphdr *nh;
 486                 __be16 offset;
 487
 488                 error = check_iphdr(skb);
 489                 if (unlikely(error)) {
 490                         if (error == -EINVAL) {
 491                                 skb->transport_header = skb->network_header;
 492                                 error = 0;
 493                         }
 494                         return error;
 495                 }
 496
 497                 nh = ip_hdr(skb);
 498                 key->ipv4.addr.src = nh->saddr;
 499                 key->ipv4.addr.dst = nh->daddr;
 500
 501                 key->ip.proto = nh->protocol;
 502                 key->ip.tos = nh->tos;
 503                 key->ip.ttl = nh->ttl;
 504
 505                 offset = nh->frag_off & htons(IP_OFFSET);
 506                 if (offset) {
 507                         key->ip.frag = OVS_FRAG_TYPE_LATER;
 508                         return 0;
 509                 }
 510                 if (nh->frag_off & htons(IP_MF) ||
 511                          skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 512                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 513
 514                 /* Transport layer. */
 515                 if (key->ip.proto == IPPROTO_TCP) {
 516                         if (tcphdr_ok(skb)) {
 517                                 struct tcphdr *tcp = tcp_hdr(skb);
 518                                 key->tp.src = tcp->source;
 519                                 key->tp.dst = tcp->dest;
 520                                 key->tp.flags = TCP_FLAGS_BE16(tcp);
 521                         }
 522                 } else if (key->ip.proto == IPPROTO_UDP) {
 523                         if (udphdr_ok(skb)) {
 524                                 struct udphdr *udp = udp_hdr(skb);
 525                                 key->tp.src = udp->source;
 526                                 key->tp.dst = udp->dest;
 527                         }
 528                 } else if (key->ip.proto == IPPROTO_SCTP) {
 529                         if (sctphdr_ok(skb)) {
 530                                 struct sctphdr *sctp = sctp_hdr(skb);
 531                                 key->tp.src = sctp->source;
 532                                 key->tp.dst = sctp->dest;
 533                         }
 534                 } else if (key->ip.proto == IPPROTO_ICMP) {
 535                         if (icmphdr_ok(skb)) {
 536                                 struct icmphdr *icmp = icmp_hdr(skb);
 537                                 /* The ICMP type and code fields use the 16-bit
 538                                  * transport port fields, so we need to store
 539                                  * them in 16-bit network byte order. */
 540                                 key->tp.src = htons(icmp->type);
 541                                 key->tp.dst = htons(icmp->code);
 542                         }
 543                 }
 544
 545         } else if ((key->eth.type == htons(ETH_P_ARP) ||
 546                    key->eth.type == htons(ETH_P_RARP)) && arphdr_ok(skb)) {
 547                 struct arp_eth_header *arp;
 548
 549                 arp = (struct arp_eth_header *)skb_network_header(skb);
 550
 551                 if (arp->ar_hrd == htons(ARPHRD_ETHER)
 552                                 && arp->ar_pro == htons(ETH_P_IP)
 553                                 && arp->ar_hln == ETH_ALEN
 554                                 && arp->ar_pln == 4) {
 555
 556                         /* We only match on the lower 8 bits of the opcode. */
 557                         if (ntohs(arp->ar_op) <= 0xff)
 558                                 key->ip.proto = ntohs(arp->ar_op);
 559                         memcpy(&key->ipv4.addr.src, arp->ar_sip, sizeof(key->ipv4.addr.src));
 560                         memcpy(&key->ipv4.addr.dst, arp->ar_tip, sizeof(key->ipv4.addr.dst));
 561                         ether_addr_copy(key->ipv4.arp.sha, arp->ar_sha);
 562                         ether_addr_copy(key->ipv4.arp.tha, arp->ar_tha);
 563                 }
 564         } else if (key->eth.type == htons(ETH_P_IPV6)) {
 565                 int nh_len;             /* IPv6 Header + Extensions */
 566
 567                 nh_len = parse_ipv6hdr(skb, key);
 568                 if (unlikely(nh_len < 0)) {
 569                         if (nh_len == -EINVAL) {
 570                                 skb->transport_header = skb->network_header;
 571                                 error = 0;
 572                         } else {
 573                                 error = nh_len;
 574                         }
 575                         return error;
 576                 }
 577
 578                 if (key->ip.frag == OVS_FRAG_TYPE_LATER)
 579                         return 0;
 580                 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 581                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 582
 583                 /* Transport layer. */
 584                 if (key->ip.proto == NEXTHDR_TCP) {
 585                         if (tcphdr_ok(skb)) {
 586                                 struct tcphdr *tcp = tcp_hdr(skb);
 587                                 key->tp.src = tcp->source;
 588                                 key->tp.dst = tcp->dest;
 589                                 key->tp.flags = TCP_FLAGS_BE16(tcp);
 590                         }
 591                 } else if (key->ip.proto == NEXTHDR_UDP) {
 592                         if (udphdr_ok(skb)) {
 593                                 struct udphdr *udp = udp_hdr(skb);
 594                                 key->tp.src = udp->source;
 595                                 key->tp.dst = udp->dest;
 596                         }
 597                 } else if (key->ip.proto == NEXTHDR_SCTP) {
 598                         if (sctphdr_ok(skb)) {
 599                                 struct sctphdr *sctp = sctp_hdr(skb);
 600                                 key->tp.src = sctp->source;
 601                                 key->tp.dst = sctp->dest;
 602                         }
 603                 } else if (key->ip.proto == NEXTHDR_ICMP) {
 604                         if (icmp6hdr_ok(skb)) {
 605                                 error = parse_icmpv6(skb, key, nh_len);
 606                                 if (error)
 607                                         return error;
 608                         }
 609                 }
 610         }
 611
 612         return 0;
 613 }