err.no Git - linux-2.6/blob - net/ipv6/reassembly.c

   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 struct inet_frags_ctl ip6_frags_ctl __read_mostly = {
  86         .high_thresh     = 256 * 1024,
  87         .low_thresh      = 192 * 1024,
  88         .timeout         = IPV6_FRAG_TIMEOUT,
  89         .secret_interval = 10 * 60 * HZ,
  90 };
  91
  92 static struct inet_frags ip6_frags;
  93
  94 int ip6_frag_nqueues(void)
  95 {
  96         return ip6_frags.nqueues;
  97 }
  98
  99 int ip6_frag_mem(void)
 100 {
 101         return atomic_read(&ip6_frags.mem);
 102 }
 103
 104 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 105                           struct net_device *dev);
 106
 107 /*
 108  * callers should be careful not to use the hash value outside the ipfrag_lock
 109  * as doing so could race with ipfrag_hash_rnd being recalculated.
 110  */
 111 static unsigned int ip6qhashfn(__be32 id, struct in6_addr *saddr,
 112                                struct in6_addr *daddr)
 113 {
 114         u32 a, b, c;
 115
 116         a = (__force u32)saddr->s6_addr32[0];
 117         b = (__force u32)saddr->s6_addr32[1];
 118         c = (__force u32)saddr->s6_addr32[2];
 119
 120         a += JHASH_GOLDEN_RATIO;
 121         b += JHASH_GOLDEN_RATIO;
 122         c += ip6_frags.rnd;
 123         __jhash_mix(a, b, c);
 124
 125         a += (__force u32)saddr->s6_addr32[3];
 126         b += (__force u32)daddr->s6_addr32[0];
 127         c += (__force u32)daddr->s6_addr32[1];
 128         __jhash_mix(a, b, c);
 129
 130         a += (__force u32)daddr->s6_addr32[2];
 131         b += (__force u32)daddr->s6_addr32[3];
 132         c += (__force u32)id;
 133         __jhash_mix(a, b, c);
 134
 135         return c & (INETFRAGS_HASHSZ - 1);
 136 }
 137
 138 static unsigned int ip6_hashfn(struct inet_frag_queue *q)
 139 {
 140         struct frag_queue *fq;
 141
 142         fq = container_of(q, struct frag_queue, q);
 143         return ip6qhashfn(fq->id, &fq->saddr, &fq->daddr);
 144 }
 145
 146 int ip6_frag_match(struct inet_frag_queue *q, void *a)
 147 {
 148         struct frag_queue *fq;
 149         struct ip6_create_arg *arg = a;
 150
 151         fq = container_of(q, struct frag_queue, q);
 152         return (fq->id == arg->id &&
 153                         ipv6_addr_equal(&fq->saddr, arg->src) &&
 154                         ipv6_addr_equal(&fq->daddr, arg->dst));
 155 }
 156 EXPORT_SYMBOL(ip6_frag_match);
 157
 158 /* Memory Tracking Functions. */
 159 static inline void frag_kfree_skb(struct sk_buff *skb, int *work)
 160 {
 161         if (work)
 162                 *work -= skb->truesize;
 163         atomic_sub(skb->truesize, &ip6_frags.mem);
 164         kfree_skb(skb);
 165 }
 166
 167 void ip6_frag_init(struct inet_frag_queue *q, void *a)
 168 {
 169         struct frag_queue *fq = container_of(q, struct frag_queue, q);
 170         struct ip6_create_arg *arg = a;
 171
 172         fq->id = arg->id;
 173         ipv6_addr_copy(&fq->saddr, arg->src);
 174         ipv6_addr_copy(&fq->daddr, arg->dst);
 175 }
 176 EXPORT_SYMBOL(ip6_frag_init);
 177
 178 /* Destruction primitives. */
 179
 180 static __inline__ void fq_put(struct frag_queue *fq)
 181 {
 182         inet_frag_put(&fq->q, &ip6_frags);
 183 }
 184
 185 /* Kill fq entry. It is not destroyed immediately,
 186  * because caller (and someone more) holds reference count.
 187  */
 188 static __inline__ void fq_kill(struct frag_queue *fq)
 189 {
 190         inet_frag_kill(&fq->q, &ip6_frags);
 191 }
 192
 193 static void ip6_evictor(struct inet6_dev *idev)
 194 {
 195         int evicted;
 196
 197         evicted = inet_frag_evictor(&ip6_frags);
 198         if (evicted)
 199                 IP6_ADD_STATS_BH(idev, IPSTATS_MIB_REASMFAILS, evicted);
 200 }
 201
 202 static void ip6_frag_expire(unsigned long data)
 203 {
 204         struct frag_queue *fq;
 205         struct net_device *dev = NULL;
 206
 207         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 208
 209         spin_lock(&fq->q.lock);
 210
 211         if (fq->q.last_in & COMPLETE)
 212                 goto out;
 213
 214         fq_kill(fq);
 215
 216         dev = dev_get_by_index(&init_net, fq->iif);
 217         if (!dev)
 218                 goto out;
 219
 220         rcu_read_lock();
 221         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 222         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 223         rcu_read_unlock();
 224
 225         /* Don't send error if the first segment did not arrive. */
 226         if (!(fq->q.last_in&FIRST_IN) || !fq->q.fragments)
 227                 goto out;
 228
 229         /*
 230            But use as source device on which LAST ARRIVED
 231            segment was received. And do not use fq->dev
 232            pointer directly, device might already disappeared.
 233          */
 234         fq->q.fragments->dev = dev;
 235         icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
 236 out:
 237         if (dev)
 238                 dev_put(dev);
 239         spin_unlock(&fq->q.lock);
 240         fq_put(fq);
 241 }
 242
 243 static __inline__ struct frag_queue *
 244 fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst,
 245         struct inet6_dev *idev)
 246 {
 247         struct inet_frag_queue *q;
 248         struct ip6_create_arg arg;
 249         unsigned int hash;
 250
 251         arg.id = id;
 252         arg.src = src;
 253         arg.dst = dst;
 254         hash = ip6qhashfn(id, src, dst);
 255
 256         q = inet_frag_find(&ip6_frags, &arg, hash);
 257         if (q == NULL)
 258                 goto oom;
 259
 260         return container_of(q, struct frag_queue, q);
 261
 262 oom:
 263         IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS);
 264         return NULL;
 265 }
 266
 267 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 268                            struct frag_hdr *fhdr, int nhoff)
 269 {
 270         struct sk_buff *prev, *next;
 271         struct net_device *dev;
 272         int offset, end;
 273
 274         if (fq->q.last_in & COMPLETE)
 275                 goto err;
 276
 277         offset = ntohs(fhdr->frag_off) & ~0x7;
 278         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 279                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 280
 281         if ((unsigned int)end > IPV6_MAXPLEN) {
 282                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 283                                  IPSTATS_MIB_INHDRERRORS);
 284                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 285                                   ((u8 *)&fhdr->frag_off -
 286                                    skb_network_header(skb)));
 287                 return -1;
 288         }
 289
 290         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 291                 const unsigned char *nh = skb_network_header(skb);
 292                 skb->csum = csum_sub(skb->csum,
 293                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 294                                                   0));
 295         }
 296
 297         /* Is this the final fragment? */
 298         if (!(fhdr->frag_off & htons(IP6_MF))) {
 299                 /* If we already have some bits beyond end
 300                  * or have different end, the segment is corrupted.
 301                  */
 302                 if (end < fq->q.len ||
 303                     ((fq->q.last_in & LAST_IN) && end != fq->q.len))
 304                         goto err;
 305                 fq->q.last_in |= LAST_IN;
 306                 fq->q.len = end;
 307         } else {
 308                 /* Check if the fragment is rounded to 8 bytes.
 309                  * Required by the RFC.
 310                  */
 311                 if (end & 0x7) {
 312                         /* RFC2460 says always send parameter problem in
 313                          * this case. -DaveM
 314                          */
 315                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 316                                          IPSTATS_MIB_INHDRERRORS);
 317                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 318                                           offsetof(struct ipv6hdr, payload_len));
 319                         return -1;
 320                 }
 321                 if (end > fq->q.len) {
 322                         /* Some bits beyond end -> corruption. */
 323                         if (fq->q.last_in & LAST_IN)
 324                                 goto err;
 325                         fq->q.len = end;
 326                 }
 327         }
 328
 329         if (end == offset)
 330                 goto err;
 331
 332         /* Point into the IP datagram 'data' part. */
 333         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 334                 goto err;
 335
 336         if (pskb_trim_rcsum(skb, end - offset))
 337                 goto err;
 338
 339         /* Find out which fragments are in front and at the back of us
 340          * in the chain of fragments so far.  We must know where to put
 341          * this fragment, right?
 342          */
 343         prev = NULL;
 344         for(next = fq->q.fragments; next != NULL; next = next->next) {
 345                 if (FRAG6_CB(next)->offset >= offset)
 346                         break;  /* bingo! */
 347                 prev = next;
 348         }
 349
 350         /* We found where to put this one.  Check for overlap with
 351          * preceding fragment, and, if needed, align things so that
 352          * any overlaps are eliminated.
 353          */
 354         if (prev) {
 355                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
 356
 357                 if (i > 0) {
 358                         offset += i;
 359                         if (end <= offset)
 360                                 goto err;
 361                         if (!pskb_pull(skb, i))
 362                                 goto err;
 363                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 364                                 skb->ip_summed = CHECKSUM_NONE;
 365                 }
 366         }
 367
 368         /* Look for overlap with succeeding segments.
 369          * If we can merge fragments, do it.
 370          */
 371         while (next && FRAG6_CB(next)->offset < end) {
 372                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
 373
 374                 if (i < next->len) {
 375                         /* Eat head of the next overlapped fragment
 376                          * and leave the loop. The next ones cannot overlap.
 377                          */
 378                         if (!pskb_pull(next, i))
 379                                 goto err;
 380                         FRAG6_CB(next)->offset += i;    /* next fragment */
 381                         fq->q.meat -= i;
 382                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 383                                 next->ip_summed = CHECKSUM_NONE;
 384                         break;
 385                 } else {
 386                         struct sk_buff *free_it = next;
 387
 388                         /* Old fragment is completely overridden with
 389                          * new one drop it.
 390                          */
 391                         next = next->next;
 392
 393                         if (prev)
 394                                 prev->next = next;
 395                         else
 396                                 fq->q.fragments = next;
 397
 398                         fq->q.meat -= free_it->len;
 399                         frag_kfree_skb(free_it, NULL);
 400                 }
 401         }
 402
 403         FRAG6_CB(skb)->offset = offset;
 404
 405         /* Insert this fragment in the chain of fragments. */
 406         skb->next = next;
 407         if (prev)
 408                 prev->next = skb;
 409         else
 410                 fq->q.fragments = skb;
 411
 412         dev = skb->dev;
 413         if (dev) {
 414                 fq->iif = dev->ifindex;
 415                 skb->dev = NULL;
 416         }
 417         fq->q.stamp = skb->tstamp;
 418         fq->q.meat += skb->len;
 419         atomic_add(skb->truesize, &ip6_frags.mem);
 420
 421         /* The first fragment.
 422          * nhoffset is obtained from the first fragment, of course.
 423          */
 424         if (offset == 0) {
 425                 fq->nhoffset = nhoff;
 426                 fq->q.last_in |= FIRST_IN;
 427         }
 428
 429         if (fq->q.last_in == (FIRST_IN | LAST_IN) && fq->q.meat == fq->q.len)
 430                 return ip6_frag_reasm(fq, prev, dev);
 431
 432         write_lock(&ip6_frags.lock);
 433         list_move_tail(&fq->q.lru_list, &ip6_frags.lru_list);
 434         write_unlock(&ip6_frags.lock);
 435         return -1;
 436
 437 err:
 438         IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 439         kfree_skb(skb);
 440         return -1;
 441 }
 442
 443 /*
 444  *      Check if this packet is complete.
 445  *      Returns NULL on failure by any reason, and pointer
 446  *      to current nexthdr field in reassembled frame.
 447  *
 448  *      It is called with locked fq, and caller must check that
 449  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 450  *      the last and the first frames arrived and all the bits are here.
 451  */
 452 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 453                           struct net_device *dev)
 454 {
 455         struct sk_buff *fp, *head = fq->q.fragments;
 456         int    payload_len;
 457         unsigned int nhoff;
 458
 459         fq_kill(fq);
 460
 461         /* Make the one we just received the head. */
 462         if (prev) {
 463                 head = prev->next;
 464                 fp = skb_clone(head, GFP_ATOMIC);
 465
 466                 if (!fp)
 467                         goto out_oom;
 468
 469                 fp->next = head->next;
 470                 prev->next = fp;
 471
 472                 skb_morph(head, fq->q.fragments);
 473                 head->next = fq->q.fragments->next;
 474
 475                 kfree_skb(fq->q.fragments);
 476                 fq->q.fragments = head;
 477         }
 478
 479         BUG_TRAP(head != NULL);
 480         BUG_TRAP(FRAG6_CB(head)->offset == 0);
 481
 482         /* Unfragmented part is taken from the first segment. */
 483         payload_len = ((head->data - skb_network_header(head)) -
 484                        sizeof(struct ipv6hdr) + fq->q.len -
 485                        sizeof(struct frag_hdr));
 486         if (payload_len > IPV6_MAXPLEN)
 487                 goto out_oversize;
 488
 489         /* Head of list must not be cloned. */
 490         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 491                 goto out_oom;
 492
 493         /* If the first fragment is fragmented itself, we split
 494          * it to two chunks: the first with data and paged part
 495          * and the second, holding only fragments. */
 496         if (skb_shinfo(head)->frag_list) {
 497                 struct sk_buff *clone;
 498                 int i, plen = 0;
 499
 500                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 501                         goto out_oom;
 502                 clone->next = head->next;
 503                 head->next = clone;
 504                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 505                 skb_shinfo(head)->frag_list = NULL;
 506                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 507                         plen += skb_shinfo(head)->frags[i].size;
 508                 clone->len = clone->data_len = head->data_len - plen;
 509                 head->data_len -= clone->len;
 510                 head->len -= clone->len;
 511                 clone->csum = 0;
 512                 clone->ip_summed = head->ip_summed;
 513                 atomic_add(clone->truesize, &ip6_frags.mem);
 514         }
 515
 516         /* We have to remove fragment header from datagram and to relocate
 517          * header in order to calculate ICV correctly. */
 518         nhoff = fq->nhoffset;
 519         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 520         memmove(head->head + sizeof(struct frag_hdr), head->head,
 521                 (head->data - head->head) - sizeof(struct frag_hdr));
 522         head->mac_header += sizeof(struct frag_hdr);
 523         head->network_header += sizeof(struct frag_hdr);
 524
 525         skb_shinfo(head)->frag_list = head->next;
 526         skb_reset_transport_header(head);
 527         skb_push(head, head->data - skb_network_header(head));
 528         atomic_sub(head->truesize, &ip6_frags.mem);
 529
 530         for (fp=head->next; fp; fp = fp->next) {
 531                 head->data_len += fp->len;
 532                 head->len += fp->len;
 533                 if (head->ip_summed != fp->ip_summed)
 534                         head->ip_summed = CHECKSUM_NONE;
 535                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 536                         head->csum = csum_add(head->csum, fp->csum);
 537                 head->truesize += fp->truesize;
 538                 atomic_sub(fp->truesize, &ip6_frags.mem);
 539         }
 540
 541         head->next = NULL;
 542         head->dev = dev;
 543         head->tstamp = fq->q.stamp;
 544         ipv6_hdr(head)->payload_len = htons(payload_len);
 545         IP6CB(head)->nhoff = nhoff;
 546
 547         /* Yes, and fold redundant checksum back. 8) */
 548         if (head->ip_summed == CHECKSUM_COMPLETE)
 549                 head->csum = csum_partial(skb_network_header(head),
 550                                           skb_network_header_len(head),
 551                                           head->csum);
 552
 553         rcu_read_lock();
 554         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 555         rcu_read_unlock();
 556         fq->q.fragments = NULL;
 557         return 1;
 558
 559 out_oversize:
 560         if (net_ratelimit())
 561                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
 562         goto out_fail;
 563 out_oom:
 564         if (net_ratelimit())
 565                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
 566 out_fail:
 567         rcu_read_lock();
 568         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 569         rcu_read_unlock();
 570         return -1;
 571 }
 572
 573 static int ipv6_frag_rcv(struct sk_buff *skb)
 574 {
 575         struct frag_hdr *fhdr;
 576         struct frag_queue *fq;
 577         struct ipv6hdr *hdr = ipv6_hdr(skb);
 578
 579         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS);
 580
 581         /* Jumbo payload inhibits frag. header */
 582         if (hdr->payload_len==0) {
 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         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 589                                  sizeof(struct frag_hdr)))) {
 590                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 591                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 592                                   skb_network_header_len(skb));
 593                 return -1;
 594         }
 595
 596         hdr = ipv6_hdr(skb);
 597         fhdr = (struct frag_hdr *)skb_transport_header(skb);
 598
 599         if (!(fhdr->frag_off & htons(0xFFF9))) {
 600                 /* It is not a fragmented frame */
 601                 skb->transport_header += sizeof(struct frag_hdr);
 602                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS);
 603
 604                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 605                 return 1;
 606         }
 607
 608         if (atomic_read(&ip6_frags.mem) > ip6_frags_ctl.high_thresh)
 609                 ip6_evictor(ip6_dst_idev(skb->dst));
 610
 611         if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr,
 612                           ip6_dst_idev(skb->dst))) != NULL) {
 613                 int ret;
 614
 615                 spin_lock(&fq->q.lock);
 616
 617                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 618
 619                 spin_unlock(&fq->q.lock);
 620                 fq_put(fq);
 621                 return ret;
 622         }
 623
 624         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 625         kfree_skb(skb);
 626         return -1;
 627 }
 628
 629 static struct inet6_protocol frag_protocol =
 630 {
 631         .handler        =       ipv6_frag_rcv,
 632         .flags          =       INET6_PROTO_NOPOLICY,
 633 };
 634
 635 void __init ipv6_frag_init(void)
 636 {
 637         if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0)
 638                 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n");
 639
 640         ip6_frags.ctl = &ip6_frags_ctl;
 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 }