datapath/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/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 = 0;
  69
  70         if (!flow->stats.is_percpu)
  71                 stats = flow->stats.stat;
  72         else
  73                 stats = this_cpu_ptr(flow->stats.cpu_stats);
  74
  75         if ((flow->key.eth.type == htons(ETH_P_IP) ||
  76              flow->key.eth.type == htons(ETH_P_IPV6)) &&
  77             flow->key.ip.proto == IPPROTO_TCP &&
  78             likely(skb->len >= skb_transport_offset(skb) + sizeof(struct tcphdr))) {
  79                 tcp_flags = TCP_FLAGS_BE16(tcp_hdr(skb));
  80         }
  81
  82         spin_lock(&stats->lock);
  83         stats->used = jiffies;
  84         stats->packet_count++;
  85         stats->byte_count += skb->len;
  86         stats->tcp_flags |= tcp_flags;
  87         spin_unlock(&stats->lock);
  88 }
  89
  90 static void stats_read(struct flow_stats *stats, bool lock_bh,
  91                        struct ovs_flow_stats *ovs_stats,
  92                        unsigned long *used, __be16 *tcp_flags)
  93 {
  94         if (lock_bh)
  95                 spin_lock_bh(&stats->lock);
  96         else
  97                 spin_lock(&stats->lock);
  98
  99         if (time_after(stats->used, *used))
 100                 *used = stats->used;
 101         *tcp_flags |= stats->tcp_flags;
 102         ovs_stats->n_packets += stats->packet_count;
 103         ovs_stats->n_bytes += stats->byte_count;
 104
 105         if (lock_bh)
 106                 spin_unlock_bh(&stats->lock);
 107         else
 108                 spin_unlock(&stats->lock);
 109 }
 110
 111 void ovs_flow_stats_get(struct sw_flow *flow, struct ovs_flow_stats *ovs_stats,
 112                         unsigned long *used, __be16 *tcp_flags)
 113 {
 114         int cpu, cur_cpu;
 115
 116         *used = 0;
 117         *tcp_flags = 0;
 118         memset(ovs_stats, 0, sizeof(*ovs_stats));
 119
 120         if (!flow->stats.is_percpu) {
 121                 stats_read(flow->stats.stat, true, ovs_stats, used, tcp_flags);
 122         } else {
 123                 cur_cpu = get_cpu();
 124
 125                 for_each_possible_cpu(cpu) {
 126                         struct flow_stats *stats;
 127                         bool lock_bh;
 128
 129                         stats = per_cpu_ptr(flow->stats.cpu_stats, cpu);
 130                         lock_bh = (cpu == cur_cpu);
 131                         stats_read(stats, lock_bh, ovs_stats, used, tcp_flags);
 132                 }
 133                 put_cpu();
 134         }
 135 }
 136
 137 static void stats_reset(struct flow_stats *stats, bool lock_bh)
 138 {
 139         if (lock_bh)
 140                 spin_lock_bh(&stats->lock);
 141         else
 142                 spin_lock(&stats->lock);
 143
 144         stats->used = 0;
 145         stats->packet_count = 0;
 146         stats->byte_count = 0;
 147         stats->tcp_flags = 0;
 148
 149         if (lock_bh)
 150                 spin_unlock_bh(&stats->lock);
 151         else
 152                 spin_unlock(&stats->lock);
 153 }
 154
 155 void ovs_flow_stats_clear(struct sw_flow *flow)
 156 {
 157         int cpu, cur_cpu;
 158
 159         if (!flow->stats.is_percpu) {
 160                 stats_reset(flow->stats.stat, true);
 161         } else {
 162                 cur_cpu = get_cpu();
 163
 164                 for_each_possible_cpu(cpu) {
 165                         bool lock_bh;
 166
 167                         lock_bh = (cpu == cur_cpu);
 168                         stats_reset(per_cpu_ptr(flow->stats.cpu_stats, cpu), lock_bh);
 169                 }
 170                 put_cpu();
 171         }
 172 }
 173
 174 static int check_header(struct sk_buff *skb, int len)
 175 {
 176         if (unlikely(skb->len < len))
 177                 return -EINVAL;
 178         if (unlikely(!pskb_may_pull(skb, len)))
 179                 return -ENOMEM;
 180         return 0;
 181 }
 182
 183 static bool arphdr_ok(struct sk_buff *skb)
 184 {
 185         return pskb_may_pull(skb, skb_network_offset(skb) +
 186                                   sizeof(struct arp_eth_header));
 187 }
 188
 189 static int check_iphdr(struct sk_buff *skb)
 190 {
 191         unsigned int nh_ofs = skb_network_offset(skb);
 192         unsigned int ip_len;
 193         int err;
 194
 195         err = check_header(skb, nh_ofs + sizeof(struct iphdr));
 196         if (unlikely(err))
 197                 return err;
 198
 199         ip_len = ip_hdrlen(skb);
 200         if (unlikely(ip_len < sizeof(struct iphdr) ||
 201                      skb->len < nh_ofs + ip_len))
 202                 return -EINVAL;
 203
 204         skb_set_transport_header(skb, nh_ofs + ip_len);
 205         return 0;
 206 }
 207
 208 static bool tcphdr_ok(struct sk_buff *skb)
 209 {
 210         int th_ofs = skb_transport_offset(skb);
 211         int tcp_len;
 212
 213         if (unlikely(!pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))))
 214                 return false;
 215
 216         tcp_len = tcp_hdrlen(skb);
 217         if (unlikely(tcp_len < sizeof(struct tcphdr) ||
 218                      skb->len < th_ofs + tcp_len))
 219                 return false;
 220
 221         return true;
 222 }
 223
 224 static bool udphdr_ok(struct sk_buff *skb)
 225 {
 226         return pskb_may_pull(skb, skb_transport_offset(skb) +
 227                                   sizeof(struct udphdr));
 228 }
 229
 230 static bool sctphdr_ok(struct sk_buff *skb)
 231 {
 232         return pskb_may_pull(skb, skb_transport_offset(skb) +
 233                                   sizeof(struct sctphdr));
 234 }
 235
 236 static bool icmphdr_ok(struct sk_buff *skb)
 237 {
 238         return pskb_may_pull(skb, skb_transport_offset(skb) +
 239                                   sizeof(struct icmphdr));
 240 }
 241
 242 static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key)
 243 {
 244         unsigned int nh_ofs = skb_network_offset(skb);
 245         unsigned int nh_len;
 246         int payload_ofs;
 247         struct ipv6hdr *nh;
 248         uint8_t nexthdr;
 249         __be16 frag_off;
 250         int err;
 251
 252         err = check_header(skb, nh_ofs + sizeof(*nh));
 253         if (unlikely(err))
 254                 return err;
 255
 256         nh = ipv6_hdr(skb);
 257         nexthdr = nh->nexthdr;
 258         payload_ofs = (u8 *)(nh + 1) - skb->data;
 259
 260         key->ip.proto = NEXTHDR_NONE;
 261         key->ip.tos = ipv6_get_dsfield(nh);
 262         key->ip.ttl = nh->hop_limit;
 263         key->ipv6.label = *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
 264         key->ipv6.addr.src = nh->saddr;
 265         key->ipv6.addr.dst = nh->daddr;
 266
 267         payload_ofs = ipv6_skip_exthdr(skb, payload_ofs, &nexthdr, &frag_off);
 268         if (unlikely(payload_ofs < 0))
 269                 return -EINVAL;
 270
 271         if (frag_off) {
 272                 if (frag_off & htons(~0x7))
 273                         key->ip.frag = OVS_FRAG_TYPE_LATER;
 274                 else
 275                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 276         }
 277
 278         nh_len = payload_ofs - nh_ofs;
 279         skb_set_transport_header(skb, nh_ofs + nh_len);
 280         key->ip.proto = nexthdr;
 281         return nh_len;
 282 }
 283
 284 static bool icmp6hdr_ok(struct sk_buff *skb)
 285 {
 286         return pskb_may_pull(skb, skb_transport_offset(skb) +
 287                                   sizeof(struct icmp6hdr));
 288 }
 289
 290 static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
 291 {
 292         struct qtag_prefix {
 293                 __be16 eth_type; /* ETH_P_8021Q */
 294                 __be16 tci;
 295         };
 296         struct qtag_prefix *qp;
 297
 298         if (unlikely(skb->len < sizeof(struct qtag_prefix) + sizeof(__be16)))
 299                 return 0;
 300
 301         if (unlikely(!pskb_may_pull(skb, sizeof(struct qtag_prefix) +
 302                                          sizeof(__be16))))
 303                 return -ENOMEM;
 304
 305         qp = (struct qtag_prefix *) skb->data;
 306         key->eth.tci = qp->tci | htons(VLAN_TAG_PRESENT);
 307         __skb_pull(skb, sizeof(struct qtag_prefix));
 308
 309         return 0;
 310 }
 311
 312 static __be16 parse_ethertype(struct sk_buff *skb)
 313 {
 314         struct llc_snap_hdr {
 315                 u8  dsap;  /* Always 0xAA */
 316                 u8  ssap;  /* Always 0xAA */
 317                 u8  ctrl;
 318                 u8  oui[3];
 319                 __be16 ethertype;
 320         };
 321         struct llc_snap_hdr *llc;
 322         __be16 proto;
 323
 324         proto = *(__be16 *) skb->data;
 325         __skb_pull(skb, sizeof(__be16));
 326
 327         if (ntohs(proto) >= ETH_P_802_3_MIN)
 328                 return proto;
 329
 330         if (skb->len < sizeof(struct llc_snap_hdr))
 331                 return htons(ETH_P_802_2);
 332
 333         if (unlikely(!pskb_may_pull(skb, sizeof(struct llc_snap_hdr))))
 334                 return htons(0);
 335
 336         llc = (struct llc_snap_hdr *) skb->data;
 337         if (llc->dsap != LLC_SAP_SNAP ||
 338             llc->ssap != LLC_SAP_SNAP ||
 339             (llc->oui[0] | llc->oui[1] | llc->oui[2]) != 0)
 340                 return htons(ETH_P_802_2);
 341
 342         __skb_pull(skb, sizeof(struct llc_snap_hdr));
 343
 344         if (ntohs(llc->ethertype) >= ETH_P_802_3_MIN)
 345                 return llc->ethertype;
 346
 347         return htons(ETH_P_802_2);
 348 }
 349
 350 static int parse_icmpv6(struct sk_buff *skb, struct sw_flow_key *key,
 351                         int nh_len)
 352 {
 353         struct icmp6hdr *icmp = icmp6_hdr(skb);
 354
 355         /* The ICMPv6 type and code fields use the 16-bit transport port
 356          * fields, so we need to store them in 16-bit network byte order.
 357          */
 358         key->ipv6.tp.src = htons(icmp->icmp6_type);
 359         key->ipv6.tp.dst = htons(icmp->icmp6_code);
 360
 361         if (icmp->icmp6_code == 0 &&
 362             (icmp->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION ||
 363              icmp->icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT)) {
 364                 int icmp_len = skb->len - skb_transport_offset(skb);
 365                 struct nd_msg *nd;
 366                 int offset;
 367
 368                 /* In order to process neighbor discovery options, we need the
 369                  * entire packet.
 370                  */
 371                 if (unlikely(icmp_len < sizeof(*nd)))
 372                         return 0;
 373
 374                 if (unlikely(skb_linearize(skb)))
 375                         return -ENOMEM;
 376
 377                 nd = (struct nd_msg *)skb_transport_header(skb);
 378                 key->ipv6.nd.target = nd->target;
 379
 380                 icmp_len -= sizeof(*nd);
 381                 offset = 0;
 382                 while (icmp_len >= 8) {
 383                         struct nd_opt_hdr *nd_opt =
 384                                  (struct nd_opt_hdr *)(nd->opt + offset);
 385                         int opt_len = nd_opt->nd_opt_len * 8;
 386
 387                         if (unlikely(!opt_len || opt_len > icmp_len))
 388                                 return 0;
 389
 390                         /* Store the link layer address if the appropriate
 391                          * option is provided.  It is considered an error if
 392                          * the same link layer option is specified twice.
 393                          */
 394                         if (nd_opt->nd_opt_type == ND_OPT_SOURCE_LL_ADDR
 395                             && opt_len == 8) {
 396                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.sll)))
 397                                         goto invalid;
 398                                 memcpy(key->ipv6.nd.sll,
 399                                     &nd->opt[offset+sizeof(*nd_opt)], ETH_ALEN);
 400                         } else if (nd_opt->nd_opt_type == ND_OPT_TARGET_LL_ADDR
 401                                    && opt_len == 8) {
 402                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.tll)))
 403                                         goto invalid;
 404                                 memcpy(key->ipv6.nd.tll,
 405                                     &nd->opt[offset+sizeof(*nd_opt)], ETH_ALEN);
 406                         }
 407
 408                         icmp_len -= opt_len;
 409                         offset += opt_len;
 410                 }
 411         }
 412
 413         return 0;
 414
 415 invalid:
 416         memset(&key->ipv6.nd.target, 0, sizeof(key->ipv6.nd.target));
 417         memset(key->ipv6.nd.sll, 0, sizeof(key->ipv6.nd.sll));
 418         memset(key->ipv6.nd.tll, 0, sizeof(key->ipv6.nd.tll));
 419
 420         return 0;
 421 }
 422
 423 /**
 424  * ovs_flow_extract - extracts a flow key from an Ethernet frame.
 425  * @skb: sk_buff that contains the frame, with skb->data pointing to the
 426  * Ethernet header
 427  * @in_port: port number on which @skb was received.
 428  * @key: output flow key
 429  *
 430  * The caller must ensure that skb->len >= ETH_HLEN.
 431  *
 432  * Returns 0 if successful, otherwise a negative errno value.
 433  *
 434  * Initializes @skb header pointers as follows:
 435  *
 436  *    - skb->mac_header: the Ethernet header.
 437  *
 438  *    - skb->network_header: just past the Ethernet header, or just past the
 439  *      VLAN header, to the first byte of the Ethernet payload.
 440  *
 441  *    - skb->transport_header: If key->eth.type is ETH_P_IP or ETH_P_IPV6
 442  *      on output, then just past the IP header, if one is present and
 443  *      of a correct length, otherwise the same as skb->network_header.
 444  *      For other key->eth.type values it is left untouched.
 445  */
 446 int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
 447 {
 448         int error;
 449         struct ethhdr *eth;
 450
 451         memset(key, 0, sizeof(*key));
 452
 453         key->phy.priority = skb->priority;
 454         if (OVS_CB(skb)->tun_key)
 455                 memcpy(&key->tun_key, OVS_CB(skb)->tun_key, sizeof(key->tun_key));
 456         key->phy.in_port = in_port;
 457         key->phy.skb_mark = skb->mark;
 458
 459         skb_reset_mac_header(skb);
 460
 461         /* Link layer.  We are guaranteed to have at least the 14 byte Ethernet
 462          * header in the linear data area.
 463          */
 464         eth = eth_hdr(skb);
 465         memcpy(key->eth.src, eth->h_source, ETH_ALEN);
 466         memcpy(key->eth.dst, eth->h_dest, ETH_ALEN);
 467
 468         __skb_pull(skb, 2 * ETH_ALEN);
 469         /* We are going to push all headers that we pull, so no need to
 470          * update skb->csum here. */
 471
 472         if (vlan_tx_tag_present(skb))
 473                 key->eth.tci = htons(vlan_get_tci(skb));
 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->ipv4.tp.src = tcp->source;
 521                                 key->ipv4.tp.dst = tcp->dest;
 522                                 key->ipv4.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->ipv4.tp.src = udp->source;
 528                                 key->ipv4.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->ipv4.tp.src = sctp->source;
 534                                 key->ipv4.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->ipv4.tp.src = htons(icmp->type);
 543                                 key->ipv4.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                         memcpy(key->ipv4.arp.sha, arp->ar_sha, ETH_ALEN);
 564                         memcpy(key->ipv4.arp.tha, arp->ar_tha, ETH_ALEN);
 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->ipv6.tp.src = tcp->source;
 590                                 key->ipv6.tp.dst = tcp->dest;
 591                                 key->ipv6.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->ipv6.tp.src = udp->source;
 597                                 key->ipv6.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->ipv6.tp.src = sctp->source;
 603                                 key->ipv6.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 }