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 /* Must be called with rcu_read_lock or ovs_mutex. */
 126 void ovs_flow_stats_get(const struct sw_flow *flow,
 127                         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 = rcu_dereference_ovsl(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 /* Called with ovs_mutex. */
 155 void ovs_flow_stats_clear(struct sw_flow *flow)
 156 {
 157         int node;
 158
 159         for_each_node(node) {
 160                 struct flow_stats *stats = ovsl_dereference(flow->stats[node]);
 161
 162                 if (stats) {
 163                         spin_lock_bh(&stats->lock);
 164                         stats->used = 0;
 165                         stats->packet_count = 0;
 166                         stats->byte_count = 0;
 167                         stats->tcp_flags = 0;
 168                         spin_unlock_bh(&stats->lock);
 169                 }
 170         }
 171 }
 172
 173 static int check_header(struct sk_buff *skb, int len)
 174 {
 175         if (unlikely(skb->len < len))
 176                 return -EINVAL;
 177         if (unlikely(!pskb_may_pull(skb, len)))
 178                 return -ENOMEM;
 179         return 0;
 180 }
 181
 182 static bool arphdr_ok(struct sk_buff *skb)
 183 {
 184         return pskb_may_pull(skb, skb_network_offset(skb) +
 185                                   sizeof(struct arp_eth_header));
 186 }
 187
 188 static int check_iphdr(struct sk_buff *skb)
 189 {
 190         unsigned int nh_ofs = skb_network_offset(skb);
 191         unsigned int ip_len;
 192         int err;
 193
 194         err = check_header(skb, nh_ofs + sizeof(struct iphdr));
 195         if (unlikely(err))
 196                 return err;
 197
 198         ip_len = ip_hdrlen(skb);
 199         if (unlikely(ip_len < sizeof(struct iphdr) ||
 200                      skb->len < nh_ofs + ip_len))
 201                 return -EINVAL;
 202
 203         skb_set_transport_header(skb, nh_ofs + ip_len);
 204         return 0;
 205 }
 206
 207 static bool tcphdr_ok(struct sk_buff *skb)
 208 {
 209         int th_ofs = skb_transport_offset(skb);
 210         int tcp_len;
 211
 212         if (unlikely(!pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))))
 213                 return false;
 214
 215         tcp_len = tcp_hdrlen(skb);
 216         if (unlikely(tcp_len < sizeof(struct tcphdr) ||
 217                      skb->len < th_ofs + tcp_len))
 218                 return false;
 219
 220         return true;
 221 }
 222
 223 static bool udphdr_ok(struct sk_buff *skb)
 224 {
 225         return pskb_may_pull(skb, skb_transport_offset(skb) +
 226                                   sizeof(struct udphdr));
 227 }
 228
 229 static bool sctphdr_ok(struct sk_buff *skb)
 230 {
 231         return pskb_may_pull(skb, skb_transport_offset(skb) +
 232                                   sizeof(struct sctphdr));
 233 }
 234
 235 static bool icmphdr_ok(struct sk_buff *skb)
 236 {
 237         return pskb_may_pull(skb, skb_transport_offset(skb) +
 238                                   sizeof(struct icmphdr));
 239 }
 240
 241 static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key)
 242 {
 243         unsigned int nh_ofs = skb_network_offset(skb);
 244         unsigned int nh_len;
 245         int payload_ofs;
 246         struct ipv6hdr *nh;
 247         uint8_t nexthdr;
 248         __be16 frag_off;
 249         int err;
 250
 251         err = check_header(skb, nh_ofs + sizeof(*nh));
 252         if (unlikely(err))
 253                 return err;
 254
 255         nh = ipv6_hdr(skb);
 256         nexthdr = nh->nexthdr;
 257         payload_ofs = (u8 *)(nh + 1) - skb->data;
 258
 259         key->ip.proto = NEXTHDR_NONE;
 260         key->ip.tos = ipv6_get_dsfield(nh);
 261         key->ip.ttl = nh->hop_limit;
 262         key->ipv6.label = *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
 263         key->ipv6.addr.src = nh->saddr;
 264         key->ipv6.addr.dst = nh->daddr;
 265
 266         payload_ofs = ipv6_skip_exthdr(skb, payload_ofs, &nexthdr, &frag_off);
 267         if (unlikely(payload_ofs < 0))
 268                 return -EINVAL;
 269
 270         if (frag_off) {
 271                 if (frag_off & htons(~0x7))
 272                         key->ip.frag = OVS_FRAG_TYPE_LATER;
 273                 else
 274                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 275         }
 276
 277         nh_len = payload_ofs - nh_ofs;
 278         skb_set_transport_header(skb, nh_ofs + nh_len);
 279         key->ip.proto = nexthdr;
 280         return nh_len;
 281 }
 282
 283 static bool icmp6hdr_ok(struct sk_buff *skb)
 284 {
 285         return pskb_may_pull(skb, skb_transport_offset(skb) +
 286                                   sizeof(struct icmp6hdr));
 287 }
 288
 289 static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
 290 {
 291         struct qtag_prefix {
 292                 __be16 eth_type; /* ETH_P_8021Q */
 293                 __be16 tci;
 294         };
 295         struct qtag_prefix *qp;
 296
 297         if (unlikely(skb->len < sizeof(struct qtag_prefix) + sizeof(__be16)))
 298                 return 0;
 299
 300         if (unlikely(!pskb_may_pull(skb, sizeof(struct qtag_prefix) +
 301                                          sizeof(__be16))))
 302                 return -ENOMEM;
 303
 304         qp = (struct qtag_prefix *) skb->data;
 305         key->eth.tci = qp->tci | htons(VLAN_TAG_PRESENT);
 306         __skb_pull(skb, sizeof(struct qtag_prefix));
 307
 308         return 0;
 309 }
 310
 311 static __be16 parse_ethertype(struct sk_buff *skb)
 312 {
 313         struct llc_snap_hdr {
 314                 u8  dsap;  /* Always 0xAA */
 315                 u8  ssap;  /* Always 0xAA */
 316                 u8  ctrl;
 317                 u8  oui[3];
 318                 __be16 ethertype;
 319         };
 320         struct llc_snap_hdr *llc;
 321         __be16 proto;
 322
 323         proto = *(__be16 *) skb->data;
 324         __skb_pull(skb, sizeof(__be16));
 325
 326         if (ntohs(proto) >= ETH_P_802_3_MIN)
 327                 return proto;
 328
 329         if (skb->len < sizeof(struct llc_snap_hdr))
 330                 return htons(ETH_P_802_2);
 331
 332         if (unlikely(!pskb_may_pull(skb, sizeof(struct llc_snap_hdr))))
 333                 return htons(0);
 334
 335         llc = (struct llc_snap_hdr *) skb->data;
 336         if (llc->dsap != LLC_SAP_SNAP ||
 337             llc->ssap != LLC_SAP_SNAP ||
 338             (llc->oui[0] | llc->oui[1] | llc->oui[2]) != 0)
 339                 return htons(ETH_P_802_2);
 340
 341         __skb_pull(skb, sizeof(struct llc_snap_hdr));
 342
 343         if (ntohs(llc->ethertype) >= ETH_P_802_3_MIN)
 344                 return llc->ethertype;
 345
 346         return htons(ETH_P_802_2);
 347 }
 348
 349 static int parse_icmpv6(struct sk_buff *skb, struct sw_flow_key *key,
 350                         int nh_len)
 351 {
 352         struct icmp6hdr *icmp = icmp6_hdr(skb);
 353
 354         /* The ICMPv6 type and code fields use the 16-bit transport port
 355          * fields, so we need to store them in 16-bit network byte order.
 356          */
 357         key->tp.src = htons(icmp->icmp6_type);
 358         key->tp.dst = htons(icmp->icmp6_code);
 359
 360         if (icmp->icmp6_code == 0 &&
 361             (icmp->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION ||
 362              icmp->icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT)) {
 363                 int icmp_len = skb->len - skb_transport_offset(skb);
 364                 struct nd_msg *nd;
 365                 int offset;
 366
 367                 /* In order to process neighbor discovery options, we need the
 368                  * entire packet.
 369                  */
 370                 if (unlikely(icmp_len < sizeof(*nd)))
 371                         return 0;
 372
 373                 if (unlikely(skb_linearize(skb)))
 374                         return -ENOMEM;
 375
 376                 nd = (struct nd_msg *)skb_transport_header(skb);
 377                 key->ipv6.nd.target = nd->target;
 378
 379                 icmp_len -= sizeof(*nd);
 380                 offset = 0;
 381                 while (icmp_len >= 8) {
 382                         struct nd_opt_hdr *nd_opt =
 383                                  (struct nd_opt_hdr *)(nd->opt + offset);
 384                         int opt_len = nd_opt->nd_opt_len * 8;
 385
 386                         if (unlikely(!opt_len || opt_len > icmp_len))
 387                                 return 0;
 388
 389                         /* Store the link layer address if the appropriate
 390                          * option is provided.  It is considered an error if
 391                          * the same link layer option is specified twice.
 392                          */
 393                         if (nd_opt->nd_opt_type == ND_OPT_SOURCE_LL_ADDR
 394                             && opt_len == 8) {
 395                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.sll)))
 396                                         goto invalid;
 397                                 ether_addr_copy(key->ipv6.nd.sll,
 398                                                 &nd->opt[offset+sizeof(*nd_opt)]);
 399                         } else if (nd_opt->nd_opt_type == ND_OPT_TARGET_LL_ADDR
 400                                    && opt_len == 8) {
 401                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.tll)))
 402                                         goto invalid;
 403                                 ether_addr_copy(key->ipv6.nd.tll,
 404                                                 &nd->opt[offset+sizeof(*nd_opt)]);
 405                         }
 406
 407                         icmp_len -= opt_len;
 408                         offset += opt_len;
 409                 }
 410         }
 411
 412         return 0;
 413
 414 invalid:
 415         memset(&key->ipv6.nd.target, 0, sizeof(key->ipv6.nd.target));
 416         memset(key->ipv6.nd.sll, 0, sizeof(key->ipv6.nd.sll));
 417         memset(key->ipv6.nd.tll, 0, sizeof(key->ipv6.nd.tll));
 418
 419         return 0;
 420 }
 421
 422 /**
 423  * ovs_flow_extract - extracts a flow key from an Ethernet frame.
 424  * @skb: sk_buff that contains the frame, with skb->data pointing to the
 425  * Ethernet header
 426  * @in_port: port number on which @skb was received.
 427  * @key: output flow key
 428  *
 429  * The caller must ensure that skb->len >= ETH_HLEN.
 430  *
 431  * Returns 0 if successful, otherwise a negative errno value.
 432  *
 433  * Initializes @skb header pointers as follows:
 434  *
 435  *    - skb->mac_header: the Ethernet header.
 436  *
 437  *    - skb->network_header: just past the Ethernet header, or just past the
 438  *      VLAN header, to the first byte of the Ethernet payload.
 439  *
 440  *    - skb->transport_header: If key->eth.type is ETH_P_IP or ETH_P_IPV6
 441  *      on output, then just past the IP header, if one is present and
 442  *      of a correct length, otherwise the same as skb->network_header.
 443  *      For other key->eth.type values it is left untouched.
 444  */
 445 int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
 446 {
 447         int error;
 448         struct ethhdr *eth;
 449
 450         memset(key, 0, sizeof(*key));
 451
 452         key->phy.priority = skb->priority;
 453         if (OVS_CB(skb)->tun_key)
 454                 memcpy(&key->tun_key, OVS_CB(skb)->tun_key, sizeof(key->tun_key));
 455         key->phy.in_port = in_port;
 456         key->phy.skb_mark = skb->mark;
 457
 458         skb_reset_mac_header(skb);
 459
 460         /* Link layer.  We are guaranteed to have at least the 14 byte Ethernet
 461          * header in the linear data area.
 462          */
 463         eth = eth_hdr(skb);
 464         ether_addr_copy(key->eth.src, eth->h_source);
 465         ether_addr_copy(key->eth.dst, eth->h_dest);
 466
 467         __skb_pull(skb, 2 * ETH_ALEN);
 468         /* We are going to push all headers that we pull, so no need to
 469          * update skb->csum here.
 470          */
 471
 472         if (vlan_tx_tag_present(skb))
 473                 key->eth.tci = htons(skb->vlan_tci);
 474         else if (eth->h_proto == htons(ETH_P_8021Q))
 475                 if (unlikely(parse_vlan(skb, key)))
 476                         return -ENOMEM;
 477
 478         key->eth.type = parse_ethertype(skb);
 479         if (unlikely(key->eth.type == htons(0)))
 480                 return -ENOMEM;
 481
 482         skb_reset_network_header(skb);
 483         __skb_push(skb, skb->data - skb_mac_header(skb));
 484
 485         /* Network layer. */
 486         if (key->eth.type == htons(ETH_P_IP)) {
 487                 struct iphdr *nh;
 488                 __be16 offset;
 489
 490                 error = check_iphdr(skb);
 491                 if (unlikely(error)) {
 492                         if (error == -EINVAL) {
 493                                 skb->transport_header = skb->network_header;
 494                                 error = 0;
 495                         }
 496                         return error;
 497                 }
 498
 499                 nh = ip_hdr(skb);
 500                 key->ipv4.addr.src = nh->saddr;
 501                 key->ipv4.addr.dst = nh->daddr;
 502
 503                 key->ip.proto = nh->protocol;
 504                 key->ip.tos = nh->tos;
 505                 key->ip.ttl = nh->ttl;
 506
 507                 offset = nh->frag_off & htons(IP_OFFSET);
 508                 if (offset) {
 509                         key->ip.frag = OVS_FRAG_TYPE_LATER;
 510                         return 0;
 511                 }
 512                 if (nh->frag_off & htons(IP_MF) ||
 513                          skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 514                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 515
 516                 /* Transport layer. */
 517                 if (key->ip.proto == IPPROTO_TCP) {
 518                         if (tcphdr_ok(skb)) {
 519                                 struct tcphdr *tcp = tcp_hdr(skb);
 520                                 key->tp.src = tcp->source;
 521                                 key->tp.dst = tcp->dest;
 522                                 key->tp.flags = TCP_FLAGS_BE16(tcp);
 523                         }
 524                 } else if (key->ip.proto == IPPROTO_UDP) {
 525                         if (udphdr_ok(skb)) {
 526                                 struct udphdr *udp = udp_hdr(skb);
 527                                 key->tp.src = udp->source;
 528                                 key->tp.dst = udp->dest;
 529                         }
 530                 } else if (key->ip.proto == IPPROTO_SCTP) {
 531                         if (sctphdr_ok(skb)) {
 532                                 struct sctphdr *sctp = sctp_hdr(skb);
 533                                 key->tp.src = sctp->source;
 534                                 key->tp.dst = sctp->dest;
 535                         }
 536                 } else if (key->ip.proto == IPPROTO_ICMP) {
 537                         if (icmphdr_ok(skb)) {
 538                                 struct icmphdr *icmp = icmp_hdr(skb);
 539                                 /* The ICMP type and code fields use the 16-bit
 540                                  * transport port fields, so we need to store
 541                                  * them in 16-bit network byte order. */
 542                                 key->tp.src = htons(icmp->type);
 543                                 key->tp.dst = htons(icmp->code);
 544                         }
 545                 }
 546
 547         } else if ((key->eth.type == htons(ETH_P_ARP) ||
 548                    key->eth.type == htons(ETH_P_RARP)) && arphdr_ok(skb)) {
 549                 struct arp_eth_header *arp;
 550
 551                 arp = (struct arp_eth_header *)skb_network_header(skb);
 552
 553                 if (arp->ar_hrd == htons(ARPHRD_ETHER)
 554                                 && arp->ar_pro == htons(ETH_P_IP)
 555                                 && arp->ar_hln == ETH_ALEN
 556                                 && arp->ar_pln == 4) {
 557
 558                         /* We only match on the lower 8 bits of the opcode. */
 559                         if (ntohs(arp->ar_op) <= 0xff)
 560                                 key->ip.proto = ntohs(arp->ar_op);
 561                         memcpy(&key->ipv4.addr.src, arp->ar_sip, sizeof(key->ipv4.addr.src));
 562                         memcpy(&key->ipv4.addr.dst, arp->ar_tip, sizeof(key->ipv4.addr.dst));
 563                         ether_addr_copy(key->ipv4.arp.sha, arp->ar_sha);
 564                         ether_addr_copy(key->ipv4.arp.tha, arp->ar_tha);
 565                 }
 566         } else if (key->eth.type == htons(ETH_P_IPV6)) {
 567                 int nh_len;             /* IPv6 Header + Extensions */
 568
 569                 nh_len = parse_ipv6hdr(skb, key);
 570                 if (unlikely(nh_len < 0)) {
 571                         if (nh_len == -EINVAL) {
 572                                 skb->transport_header = skb->network_header;
 573                                 error = 0;
 574                         } else {
 575                                 error = nh_len;
 576                         }
 577                         return error;
 578                 }
 579
 580                 if (key->ip.frag == OVS_FRAG_TYPE_LATER)
 581                         return 0;
 582                 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 583                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 584
 585                 /* Transport layer. */
 586                 if (key->ip.proto == NEXTHDR_TCP) {
 587                         if (tcphdr_ok(skb)) {
 588                                 struct tcphdr *tcp = tcp_hdr(skb);
 589                                 key->tp.src = tcp->source;
 590                                 key->tp.dst = tcp->dest;
 591                                 key->tp.flags = TCP_FLAGS_BE16(tcp);
 592                         }
 593                 } else if (key->ip.proto == NEXTHDR_UDP) {
 594                         if (udphdr_ok(skb)) {
 595                                 struct udphdr *udp = udp_hdr(skb);
 596                                 key->tp.src = udp->source;
 597                                 key->tp.dst = udp->dest;
 598                         }
 599                 } else if (key->ip.proto == NEXTHDR_SCTP) {
 600                         if (sctphdr_ok(skb)) {
 601                                 struct sctphdr *sctp = sctp_hdr(skb);
 602                                 key->tp.src = sctp->source;
 603                                 key->tp.dst = sctp->dest;
 604                         }
 605                 } else if (key->ip.proto == NEXTHDR_ICMP) {
 606                         if (icmp6hdr_ok(skb)) {
 607                                 error = parse_icmpv6(skb, key, nh_len);
 608                                 if (error)
 609                                         return error;
 610                         }
 611                 }
 612         }
 613
 614         return 0;
 615 }