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   1 /*
   2  *      IPv6 fragment reassembly
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      $Id: reassembly.c,v 1.26 2001/03/07 22:00:57 davem Exp $
   9  *
  10  *      Based on: net/ipv4/ip_fragment.c
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  */
  17
  18 /*
  19  *      Fixes:
  20  *      Andi Kleen      Make it work with multiple hosts.
  21  *                      More RFC compliance.
  22  *
  23  *      Horst von Brand Add missing #include <linux/string.h>
  24  *      Alexey Kuznetsov        SMP races, threading, cleanup.
  25  *      Patrick McHardy         LRU queue of frag heads for evictor.
  26  *      Mitsuru KANDA @USAGI    Register inet6_protocol{}.
  27  *      David Stevens and
  28  *      YOSHIFUJI,H. @USAGI     Always remove fragment header to
  29  *                              calculate ICV correctly.
  30  */
  31 #include <linux/errno.h>
  32 #include <linux/types.h>
  33 #include <linux/string.h>
  34 #include <linux/socket.h>
  35 #include <linux/sockios.h>
  36 #include <linux/jiffies.h>
  37 #include <linux/net.h>
  38 #include <linux/list.h>
  39 #include <linux/netdevice.h>
  40 #include <linux/in6.h>
  41 #include <linux/ipv6.h>
  42 #include <linux/icmpv6.h>
  43 #include <linux/random.h>
  44 #include <linux/jhash.h>
  45 #include <linux/skbuff.h>
  46
  47 #include <net/sock.h>
  48 #include <net/snmp.h>
  49
  50 #include <net/ipv6.h>
  51 #include <net/ip6_route.h>
  52 #include <net/protocol.h>
  53 #include <net/transp_v6.h>
  54 #include <net/rawv6.h>
  55 #include <net/ndisc.h>
  56 #include <net/addrconf.h>
  57 #include <net/inet_frag.h>
  58
  59 struct ip6frag_skb_cb
  60 {
  61         struct inet6_skb_parm   h;
  62         int                     offset;
  63 };
  64
  65 #define FRAG6_CB(skb)   ((struct ip6frag_skb_cb*)((skb)->cb))
  66
  67
  68 /*
  69  *      Equivalent of ipv4 struct ipq
  70  */
  71
  72 struct frag_queue
  73 {
  74         struct inet_frag_queue  q;
  75
  76         __be32                  id;             /* fragment id          */
  77         struct in6_addr         saddr;
  78         struct in6_addr         daddr;
  79
  80         int                     iif;
  81         unsigned int            csum;
  82         __u16                   nhoffset;
  83 };
  84
  85 static struct inet_frags ip6_frags;
  86
  87 int ip6_frag_nqueues(void)
  88 {
  89         return ip6_frags.nqueues;
  90 }
  91
  92 int ip6_frag_mem(void)
  93 {
  94         return atomic_read(&ip6_frags.mem);
  95 }
  96
  97 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
  98                           struct net_device *dev);
  99
 100 /*
 101  * callers should be careful not to use the hash value outside the ipfrag_lock
 102  * as doing so could race with ipfrag_hash_rnd being recalculated.
 103  */
 104 static unsigned int ip6qhashfn(__be32 id, struct in6_addr *saddr,
 105                                struct in6_addr *daddr)
 106 {
 107         u32 a, b, c;
 108
 109         a = (__force u32)saddr->s6_addr32[0];
 110         b = (__force u32)saddr->s6_addr32[1];
 111         c = (__force u32)saddr->s6_addr32[2];
 112
 113         a += JHASH_GOLDEN_RATIO;
 114         b += JHASH_GOLDEN_RATIO;
 115         c += ip6_frags.rnd;
 116         __jhash_mix(a, b, c);
 117
 118         a += (__force u32)saddr->s6_addr32[3];
 119         b += (__force u32)daddr->s6_addr32[0];
 120         c += (__force u32)daddr->s6_addr32[1];
 121         __jhash_mix(a, b, c);
 122
 123         a += (__force u32)daddr->s6_addr32[2];
 124         b += (__force u32)daddr->s6_addr32[3];
 125         c += (__force u32)id;
 126         __jhash_mix(a, b, c);
 127
 128         return c & (INETFRAGS_HASHSZ - 1);
 129 }
 130
 131 static unsigned int ip6_hashfn(struct inet_frag_queue *q)
 132 {
 133         struct frag_queue *fq;
 134
 135         fq = container_of(q, struct frag_queue, q);
 136         return ip6qhashfn(fq->id, &fq->saddr, &fq->daddr);
 137 }
 138
 139 int ip6_frag_match(struct inet_frag_queue *q, void *a)
 140 {
 141         struct frag_queue *fq;
 142         struct ip6_create_arg *arg = a;
 143
 144         fq = container_of(q, struct frag_queue, q);
 145         return (fq->id == arg->id &&
 146                         ipv6_addr_equal(&fq->saddr, arg->src) &&
 147                         ipv6_addr_equal(&fq->daddr, arg->dst));
 148 }
 149 EXPORT_SYMBOL(ip6_frag_match);
 150
 151 /* Memory Tracking Functions. */
 152 static inline void frag_kfree_skb(struct sk_buff *skb, int *work)
 153 {
 154         if (work)
 155                 *work -= skb->truesize;
 156         atomic_sub(skb->truesize, &ip6_frags.mem);
 157         kfree_skb(skb);
 158 }
 159
 160 void ip6_frag_init(struct inet_frag_queue *q, void *a)
 161 {
 162         struct frag_queue *fq = container_of(q, struct frag_queue, q);
 163         struct ip6_create_arg *arg = a;
 164
 165         fq->id = arg->id;
 166         ipv6_addr_copy(&fq->saddr, arg->src);
 167         ipv6_addr_copy(&fq->daddr, arg->dst);
 168 }
 169 EXPORT_SYMBOL(ip6_frag_init);
 170
 171 /* Destruction primitives. */
 172
 173 static __inline__ void fq_put(struct frag_queue *fq)
 174 {
 175         inet_frag_put(&fq->q, &ip6_frags);
 176 }
 177
 178 /* Kill fq entry. It is not destroyed immediately,
 179  * because caller (and someone more) holds reference count.
 180  */
 181 static __inline__ void fq_kill(struct frag_queue *fq)
 182 {
 183         inet_frag_kill(&fq->q, &ip6_frags);
 184 }
 185
 186 static void ip6_evictor(struct inet6_dev *idev)
 187 {
 188         int evicted;
 189
 190         evicted = inet_frag_evictor(&ip6_frags);
 191         if (evicted)
 192                 IP6_ADD_STATS_BH(idev, IPSTATS_MIB_REASMFAILS, evicted);
 193 }
 194
 195 static void ip6_frag_expire(unsigned long data)
 196 {
 197         struct frag_queue *fq;
 198         struct net_device *dev = NULL;
 199
 200         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 201
 202         spin_lock(&fq->q.lock);
 203
 204         if (fq->q.last_in & COMPLETE)
 205                 goto out;
 206
 207         fq_kill(fq);
 208
 209         dev = dev_get_by_index(&init_net, fq->iif);
 210         if (!dev)
 211                 goto out;
 212
 213         rcu_read_lock();
 214         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 215         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 216         rcu_read_unlock();
 217
 218         /* Don't send error if the first segment did not arrive. */
 219         if (!(fq->q.last_in&FIRST_IN) || !fq->q.fragments)
 220                 goto out;
 221
 222         /*
 223            But use as source device on which LAST ARRIVED
 224            segment was received. And do not use fq->dev
 225            pointer directly, device might already disappeared.
 226          */
 227         fq->q.fragments->dev = dev;
 228         icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
 229 out:
 230         if (dev)
 231                 dev_put(dev);
 232         spin_unlock(&fq->q.lock);
 233         fq_put(fq);
 234 }
 235
 236 static __inline__ struct frag_queue *
 237 fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst,
 238         struct inet6_dev *idev)
 239 {
 240         struct inet_frag_queue *q;
 241         struct ip6_create_arg arg;
 242         unsigned int hash;
 243
 244         arg.id = id;
 245         arg.src = src;
 246         arg.dst = dst;
 247         hash = ip6qhashfn(id, src, dst);
 248
 249         q = inet_frag_find(&ip6_frags, &arg, hash);
 250         if (q == NULL)
 251                 goto oom;
 252
 253         return container_of(q, struct frag_queue, q);
 254
 255 oom:
 256         IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS);
 257         return NULL;
 258 }
 259
 260 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 261                            struct frag_hdr *fhdr, int nhoff)
 262 {
 263         struct sk_buff *prev, *next;
 264         struct net_device *dev;
 265         int offset, end;
 266
 267         if (fq->q.last_in & COMPLETE)
 268                 goto err;
 269
 270         offset = ntohs(fhdr->frag_off) & ~0x7;
 271         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 272                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 273
 274         if ((unsigned int)end > IPV6_MAXPLEN) {
 275                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 276                                  IPSTATS_MIB_INHDRERRORS);
 277                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 278                                   ((u8 *)&fhdr->frag_off -
 279                                    skb_network_header(skb)));
 280                 return -1;
 281         }
 282
 283         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 284                 const unsigned char *nh = skb_network_header(skb);
 285                 skb->csum = csum_sub(skb->csum,
 286                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 287                                                   0));
 288         }
 289
 290         /* Is this the final fragment? */
 291         if (!(fhdr->frag_off & htons(IP6_MF))) {
 292                 /* If we already have some bits beyond end
 293                  * or have different end, the segment is corrupted.
 294                  */
 295                 if (end < fq->q.len ||
 296                     ((fq->q.last_in & LAST_IN) && end != fq->q.len))
 297                         goto err;
 298                 fq->q.last_in |= LAST_IN;
 299                 fq->q.len = end;
 300         } else {
 301                 /* Check if the fragment is rounded to 8 bytes.
 302                  * Required by the RFC.
 303                  */
 304                 if (end & 0x7) {
 305                         /* RFC2460 says always send parameter problem in
 306                          * this case. -DaveM
 307                          */
 308                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 309                                          IPSTATS_MIB_INHDRERRORS);
 310                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 311                                           offsetof(struct ipv6hdr, payload_len));
 312                         return -1;
 313                 }
 314                 if (end > fq->q.len) {
 315                         /* Some bits beyond end -> corruption. */
 316                         if (fq->q.last_in & LAST_IN)
 317                                 goto err;
 318                         fq->q.len = end;
 319                 }
 320         }
 321
 322         if (end == offset)
 323                 goto err;
 324
 325         /* Point into the IP datagram 'data' part. */
 326         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 327                 goto err;
 328
 329         if (pskb_trim_rcsum(skb, end - offset))
 330                 goto err;
 331
 332         /* Find out which fragments are in front and at the back of us
 333          * in the chain of fragments so far.  We must know where to put
 334          * this fragment, right?
 335          */
 336         prev = NULL;
 337         for(next = fq->q.fragments; next != NULL; next = next->next) {
 338                 if (FRAG6_CB(next)->offset >= offset)
 339                         break;  /* bingo! */
 340                 prev = next;
 341         }
 342
 343         /* We found where to put this one.  Check for overlap with
 344          * preceding fragment, and, if needed, align things so that
 345          * any overlaps are eliminated.
 346          */
 347         if (prev) {
 348                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
 349
 350                 if (i > 0) {
 351                         offset += i;
 352                         if (end <= offset)
 353                                 goto err;
 354                         if (!pskb_pull(skb, i))
 355                                 goto err;
 356                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 357                                 skb->ip_summed = CHECKSUM_NONE;
 358                 }
 359         }
 360
 361         /* Look for overlap with succeeding segments.
 362          * If we can merge fragments, do it.
 363          */
 364         while (next && FRAG6_CB(next)->offset < end) {
 365                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
 366
 367                 if (i < next->len) {
 368                         /* Eat head of the next overlapped fragment
 369                          * and leave the loop. The next ones cannot overlap.
 370                          */
 371                         if (!pskb_pull(next, i))
 372                                 goto err;
 373                         FRAG6_CB(next)->offset += i;    /* next fragment */
 374                         fq->q.meat -= i;
 375                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 376                                 next->ip_summed = CHECKSUM_NONE;
 377                         break;
 378                 } else {
 379                         struct sk_buff *free_it = next;
 380
 381                         /* Old fragment is completely overridden with
 382                          * new one drop it.
 383                          */
 384                         next = next->next;
 385
 386                         if (prev)
 387                                 prev->next = next;
 388                         else
 389                                 fq->q.fragments = next;
 390
 391                         fq->q.meat -= free_it->len;
 392                         frag_kfree_skb(free_it, NULL);
 393                 }
 394         }
 395
 396         FRAG6_CB(skb)->offset = offset;
 397
 398         /* Insert this fragment in the chain of fragments. */
 399         skb->next = next;
 400         if (prev)
 401                 prev->next = skb;
 402         else
 403                 fq->q.fragments = skb;
 404
 405         dev = skb->dev;
 406         if (dev) {
 407                 fq->iif = dev->ifindex;
 408                 skb->dev = NULL;
 409         }
 410         fq->q.stamp = skb->tstamp;
 411         fq->q.meat += skb->len;
 412         atomic_add(skb->truesize, &ip6_frags.mem);
 413
 414         /* The first fragment.
 415          * nhoffset is obtained from the first fragment, of course.
 416          */
 417         if (offset == 0) {
 418                 fq->nhoffset = nhoff;
 419                 fq->q.last_in |= FIRST_IN;
 420         }
 421
 422         if (fq->q.last_in == (FIRST_IN | LAST_IN) && fq->q.meat == fq->q.len)
 423                 return ip6_frag_reasm(fq, prev, dev);
 424
 425         write_lock(&ip6_frags.lock);
 426         list_move_tail(&fq->q.lru_list, &ip6_frags.lru_list);
 427         write_unlock(&ip6_frags.lock);
 428         return -1;
 429
 430 err:
 431         IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 432         kfree_skb(skb);
 433         return -1;
 434 }
 435
 436 /*
 437  *      Check if this packet is complete.
 438  *      Returns NULL on failure by any reason, and pointer
 439  *      to current nexthdr field in reassembled frame.
 440  *
 441  *      It is called with locked fq, and caller must check that
 442  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 443  *      the last and the first frames arrived and all the bits are here.
 444  */
 445 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 446                           struct net_device *dev)
 447 {
 448         struct sk_buff *fp, *head = fq->q.fragments;
 449         int    payload_len;
 450         unsigned int nhoff;
 451
 452         fq_kill(fq);
 453
 454         /* Make the one we just received the head. */
 455         if (prev) {
 456                 head = prev->next;
 457                 fp = skb_clone(head, GFP_ATOMIC);
 458
 459                 if (!fp)
 460                         goto out_oom;
 461
 462                 fp->next = head->next;
 463                 prev->next = fp;
 464
 465                 skb_morph(head, fq->q.fragments);
 466                 head->next = fq->q.fragments->next;
 467
 468                 kfree_skb(fq->q.fragments);
 469                 fq->q.fragments = head;
 470         }
 471
 472         BUG_TRAP(head != NULL);
 473         BUG_TRAP(FRAG6_CB(head)->offset == 0);
 474
 475         /* Unfragmented part is taken from the first segment. */
 476         payload_len = ((head->data - skb_network_header(head)) -
 477                        sizeof(struct ipv6hdr) + fq->q.len -
 478                        sizeof(struct frag_hdr));
 479         if (payload_len > IPV6_MAXPLEN)
 480                 goto out_oversize;
 481
 482         /* Head of list must not be cloned. */
 483         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 484                 goto out_oom;
 485
 486         /* If the first fragment is fragmented itself, we split
 487          * it to two chunks: the first with data and paged part
 488          * and the second, holding only fragments. */
 489         if (skb_shinfo(head)->frag_list) {
 490                 struct sk_buff *clone;
 491                 int i, plen = 0;
 492
 493                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 494                         goto out_oom;
 495                 clone->next = head->next;
 496                 head->next = clone;
 497                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 498                 skb_shinfo(head)->frag_list = NULL;
 499                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 500                         plen += skb_shinfo(head)->frags[i].size;
 501                 clone->len = clone->data_len = head->data_len - plen;
 502                 head->data_len -= clone->len;
 503                 head->len -= clone->len;
 504                 clone->csum = 0;
 505                 clone->ip_summed = head->ip_summed;
 506                 atomic_add(clone->truesize, &ip6_frags.mem);
 507         }
 508
 509         /* We have to remove fragment header from datagram and to relocate
 510          * header in order to calculate ICV correctly. */
 511         nhoff = fq->nhoffset;
 512         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 513         memmove(head->head + sizeof(struct frag_hdr), head->head,
 514                 (head->data - head->head) - sizeof(struct frag_hdr));
 515         head->mac_header += sizeof(struct frag_hdr);
 516         head->network_header += sizeof(struct frag_hdr);
 517
 518         skb_shinfo(head)->frag_list = head->next;
 519         skb_reset_transport_header(head);
 520         skb_push(head, head->data - skb_network_header(head));
 521         atomic_sub(head->truesize, &ip6_frags.mem);
 522
 523         for (fp=head->next; fp; fp = fp->next) {
 524                 head->data_len += fp->len;
 525                 head->len += fp->len;
 526                 if (head->ip_summed != fp->ip_summed)
 527                         head->ip_summed = CHECKSUM_NONE;
 528                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 529                         head->csum = csum_add(head->csum, fp->csum);
 530                 head->truesize += fp->truesize;
 531                 atomic_sub(fp->truesize, &ip6_frags.mem);
 532         }
 533
 534         head->next = NULL;
 535         head->dev = dev;
 536         head->tstamp = fq->q.stamp;
 537         ipv6_hdr(head)->payload_len = htons(payload_len);
 538         IP6CB(head)->nhoff = nhoff;
 539
 540         /* Yes, and fold redundant checksum back. 8) */
 541         if (head->ip_summed == CHECKSUM_COMPLETE)
 542                 head->csum = csum_partial(skb_network_header(head),
 543                                           skb_network_header_len(head),
 544                                           head->csum);
 545
 546         rcu_read_lock();
 547         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 548         rcu_read_unlock();
 549         fq->q.fragments = NULL;
 550         return 1;
 551
 552 out_oversize:
 553         if (net_ratelimit())
 554                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
 555         goto out_fail;
 556 out_oom:
 557         if (net_ratelimit())
 558                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
 559 out_fail:
 560         rcu_read_lock();
 561         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 562         rcu_read_unlock();
 563         return -1;
 564 }
 565
 566 static int ipv6_frag_rcv(struct sk_buff *skb)
 567 {
 568         struct frag_hdr *fhdr;
 569         struct frag_queue *fq;
 570         struct ipv6hdr *hdr = ipv6_hdr(skb);
 571
 572         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS);
 573
 574         /* Jumbo payload inhibits frag. header */
 575         if (hdr->payload_len==0) {
 576                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 577                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 578                                   skb_network_header_len(skb));
 579                 return -1;
 580         }
 581         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 582                                  sizeof(struct frag_hdr)))) {
 583                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 584                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 585                                   skb_network_header_len(skb));
 586                 return -1;
 587         }
 588
 589         hdr = ipv6_hdr(skb);
 590         fhdr = (struct frag_hdr *)skb_transport_header(skb);
 591
 592         if (!(fhdr->frag_off & htons(0xFFF9))) {
 593                 /* It is not a fragmented frame */
 594                 skb->transport_header += sizeof(struct frag_hdr);
 595                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS);
 596
 597                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 598                 return 1;
 599         }
 600
 601         if (atomic_read(&ip6_frags.mem) > init_net.ipv6.sysctl.frags.high_thresh)
 602                 ip6_evictor(ip6_dst_idev(skb->dst));
 603
 604         if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr,
 605                           ip6_dst_idev(skb->dst))) != NULL) {
 606                 int ret;
 607
 608                 spin_lock(&fq->q.lock);
 609
 610                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 611
 612                 spin_unlock(&fq->q.lock);
 613                 fq_put(fq);
 614                 return ret;
 615         }
 616
 617         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 618         kfree_skb(skb);
 619         return -1;
 620 }
 621
 622 static struct inet6_protocol frag_protocol =
 623 {
 624         .handler        =       ipv6_frag_rcv,
 625         .flags          =       INET6_PROTO_NOPOLICY,
 626 };
 627
 628 void ipv6_frag_sysctl_init(struct net *net)
 629 {
 630         ip6_frags.ctl = &net->ipv6.sysctl.frags;
 631 }
 632
 633 int __init ipv6_frag_init(void)
 634 {
 635         int ret;
 636
 637         ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 638         if (ret)
 639                 goto out;
 640
 641         ip6_frags.hashfn = ip6_hashfn;
 642         ip6_frags.constructor = ip6_frag_init;
 643         ip6_frags.destructor = NULL;
 644         ip6_frags.skb_free = NULL;
 645         ip6_frags.qsize = sizeof(struct frag_queue);
 646         ip6_frags.match = ip6_frag_match;
 647         ip6_frags.frag_expire = ip6_frag_expire;
 648         inet_frags_init(&ip6_frags);
 649 out:
 650         return ret;
 651 }
 652
 653 void ipv6_frag_exit(void)
 654 {
 655         inet_frags_fini(&ip6_frags);
 656         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 657 }