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