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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 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_equal(struct inet_frag_queue *q1, struct inet_frag_queue *q2)
 147 {
 148         struct frag_queue *fq1, *fq2;
 149
 150         fq1 = container_of(q1, struct frag_queue, q);
 151         fq2 = container_of(q2, struct frag_queue, q);
 152         return (fq1->id == fq2->id &&
 153                         ipv6_addr_equal(&fq2->saddr, &fq1->saddr) &&
 154                         ipv6_addr_equal(&fq2->daddr, &fq1->daddr));
 155 }
 156 EXPORT_SYMBOL(ip6_frag_equal);
 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 static void ip6_frag_free(struct inet_frag_queue *fq)
 179 {
 180         kfree(container_of(fq, struct frag_queue, q));
 181 }
 182
 183 /* Destruction primitives. */
 184
 185 static __inline__ void fq_put(struct frag_queue *fq)
 186 {
 187         inet_frag_put(&fq->q, &ip6_frags);
 188 }
 189
 190 /* Kill fq entry. It is not destroyed immediately,
 191  * because caller (and someone more) holds reference count.
 192  */
 193 static __inline__ void fq_kill(struct frag_queue *fq)
 194 {
 195         inet_frag_kill(&fq->q, &ip6_frags);
 196 }
 197
 198 static void ip6_evictor(struct inet6_dev *idev)
 199 {
 200         int evicted;
 201
 202         evicted = inet_frag_evictor(&ip6_frags);
 203         if (evicted)
 204                 IP6_ADD_STATS_BH(idev, IPSTATS_MIB_REASMFAILS, evicted);
 205 }
 206
 207 static void ip6_frag_expire(unsigned long data)
 208 {
 209         struct frag_queue *fq;
 210         struct net_device *dev = NULL;
 211
 212         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 213
 214         spin_lock(&fq->q.lock);
 215
 216         if (fq->q.last_in & COMPLETE)
 217                 goto out;
 218
 219         fq_kill(fq);
 220
 221         dev = dev_get_by_index(&init_net, fq->iif);
 222         if (!dev)
 223                 goto out;
 224
 225         rcu_read_lock();
 226         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 227         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 228         rcu_read_unlock();
 229
 230         /* Don't send error if the first segment did not arrive. */
 231         if (!(fq->q.last_in&FIRST_IN) || !fq->q.fragments)
 232                 goto out;
 233
 234         /*
 235            But use as source device on which LAST ARRIVED
 236            segment was received. And do not use fq->dev
 237            pointer directly, device might already disappeared.
 238          */
 239         fq->q.fragments->dev = dev;
 240         icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
 241 out:
 242         if (dev)
 243                 dev_put(dev);
 244         spin_unlock(&fq->q.lock);
 245         fq_put(fq);
 246 }
 247
 248 /* Creation primitives. */
 249
 250 static struct frag_queue *
 251 ip6_frag_create(__be32 id, struct in6_addr *src, struct in6_addr *dst,
 252                 struct inet6_dev *idev, unsigned int hash)
 253 {
 254         struct inet_frag_queue *q;
 255         struct ip6_create_arg arg;
 256
 257         arg.id = id;
 258         arg.src = src;
 259         arg.dst = dst;
 260
 261         q = inet_frag_create(&ip6_frags, &arg, hash);
 262         if (q == NULL)
 263                 goto oom;
 264
 265         return container_of(q, struct frag_queue, q);
 266
 267 oom:
 268         IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS);
 269         return NULL;
 270 }
 271
 272 static __inline__ struct frag_queue *
 273 fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst,
 274         struct inet6_dev *idev)
 275 {
 276         struct frag_queue *fq;
 277         struct hlist_node *n;
 278         unsigned int hash;
 279
 280         read_lock(&ip6_frags.lock);
 281         hash = ip6qhashfn(id, src, dst);
 282         hlist_for_each_entry(fq, n, &ip6_frags.hash[hash], q.list) {
 283                 if (fq->id == id &&
 284                     ipv6_addr_equal(src, &fq->saddr) &&
 285                     ipv6_addr_equal(dst, &fq->daddr)) {
 286                         atomic_inc(&fq->q.refcnt);
 287                         read_unlock(&ip6_frags.lock);
 288                         return fq;
 289                 }
 290         }
 291         read_unlock(&ip6_frags.lock);
 292
 293         return ip6_frag_create(id, src, dst, idev, hash);
 294 }
 295
 296
 297 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 298                            struct frag_hdr *fhdr, int nhoff)
 299 {
 300         struct sk_buff *prev, *next;
 301         struct net_device *dev;
 302         int offset, end;
 303
 304         if (fq->q.last_in & COMPLETE)
 305                 goto err;
 306
 307         offset = ntohs(fhdr->frag_off) & ~0x7;
 308         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 309                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 310
 311         if ((unsigned int)end > IPV6_MAXPLEN) {
 312                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 313                                  IPSTATS_MIB_INHDRERRORS);
 314                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 315                                   ((u8 *)&fhdr->frag_off -
 316                                    skb_network_header(skb)));
 317                 return -1;
 318         }
 319
 320         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 321                 const unsigned char *nh = skb_network_header(skb);
 322                 skb->csum = csum_sub(skb->csum,
 323                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 324                                                   0));
 325         }
 326
 327         /* Is this the final fragment? */
 328         if (!(fhdr->frag_off & htons(IP6_MF))) {
 329                 /* If we already have some bits beyond end
 330                  * or have different end, the segment is corrupted.
 331                  */
 332                 if (end < fq->q.len ||
 333                     ((fq->q.last_in & LAST_IN) && end != fq->q.len))
 334                         goto err;
 335                 fq->q.last_in |= LAST_IN;
 336                 fq->q.len = end;
 337         } else {
 338                 /* Check if the fragment is rounded to 8 bytes.
 339                  * Required by the RFC.
 340                  */
 341                 if (end & 0x7) {
 342                         /* RFC2460 says always send parameter problem in
 343                          * this case. -DaveM
 344                          */
 345                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 346                                          IPSTATS_MIB_INHDRERRORS);
 347                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 348                                           offsetof(struct ipv6hdr, payload_len));
 349                         return -1;
 350                 }
 351                 if (end > fq->q.len) {
 352                         /* Some bits beyond end -> corruption. */
 353                         if (fq->q.last_in & LAST_IN)
 354                                 goto err;
 355                         fq->q.len = end;
 356                 }
 357         }
 358
 359         if (end == offset)
 360                 goto err;
 361
 362         /* Point into the IP datagram 'data' part. */
 363         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 364                 goto err;
 365
 366         if (pskb_trim_rcsum(skb, end - offset))
 367                 goto err;
 368
 369         /* Find out which fragments are in front and at the back of us
 370          * in the chain of fragments so far.  We must know where to put
 371          * this fragment, right?
 372          */
 373         prev = NULL;
 374         for(next = fq->q.fragments; next != NULL; next = next->next) {
 375                 if (FRAG6_CB(next)->offset >= offset)
 376                         break;  /* bingo! */
 377                 prev = next;
 378         }
 379
 380         /* We found where to put this one.  Check for overlap with
 381          * preceding fragment, and, if needed, align things so that
 382          * any overlaps are eliminated.
 383          */
 384         if (prev) {
 385                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
 386
 387                 if (i > 0) {
 388                         offset += i;
 389                         if (end <= offset)
 390                                 goto err;
 391                         if (!pskb_pull(skb, i))
 392                                 goto err;
 393                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 394                                 skb->ip_summed = CHECKSUM_NONE;
 395                 }
 396         }
 397
 398         /* Look for overlap with succeeding segments.
 399          * If we can merge fragments, do it.
 400          */
 401         while (next && FRAG6_CB(next)->offset < end) {
 402                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
 403
 404                 if (i < next->len) {
 405                         /* Eat head of the next overlapped fragment
 406                          * and leave the loop. The next ones cannot overlap.
 407                          */
 408                         if (!pskb_pull(next, i))
 409                                 goto err;
 410                         FRAG6_CB(next)->offset += i;    /* next fragment */
 411                         fq->q.meat -= i;
 412                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 413                                 next->ip_summed = CHECKSUM_NONE;
 414                         break;
 415                 } else {
 416                         struct sk_buff *free_it = next;
 417
 418                         /* Old fragment is completely overridden with
 419                          * new one drop it.
 420                          */
 421                         next = next->next;
 422
 423                         if (prev)
 424                                 prev->next = next;
 425                         else
 426                                 fq->q.fragments = next;
 427
 428                         fq->q.meat -= free_it->len;
 429                         frag_kfree_skb(free_it, NULL);
 430                 }
 431         }
 432
 433         FRAG6_CB(skb)->offset = offset;
 434
 435         /* Insert this fragment in the chain of fragments. */
 436         skb->next = next;
 437         if (prev)
 438                 prev->next = skb;
 439         else
 440                 fq->q.fragments = skb;
 441
 442         dev = skb->dev;
 443         if (dev) {
 444                 fq->iif = dev->ifindex;
 445                 skb->dev = NULL;
 446         }
 447         fq->q.stamp = skb->tstamp;
 448         fq->q.meat += skb->len;
 449         atomic_add(skb->truesize, &ip6_frags.mem);
 450
 451         /* The first fragment.
 452          * nhoffset is obtained from the first fragment, of course.
 453          */
 454         if (offset == 0) {
 455                 fq->nhoffset = nhoff;
 456                 fq->q.last_in |= FIRST_IN;
 457         }
 458
 459         if (fq->q.last_in == (FIRST_IN | LAST_IN) && fq->q.meat == fq->q.len)
 460                 return ip6_frag_reasm(fq, prev, dev);
 461
 462         write_lock(&ip6_frags.lock);
 463         list_move_tail(&fq->q.lru_list, &ip6_frags.lru_list);
 464         write_unlock(&ip6_frags.lock);
 465         return -1;
 466
 467 err:
 468         IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 469         kfree_skb(skb);
 470         return -1;
 471 }
 472
 473 /*
 474  *      Check if this packet is complete.
 475  *      Returns NULL on failure by any reason, and pointer
 476  *      to current nexthdr field in reassembled frame.
 477  *
 478  *      It is called with locked fq, and caller must check that
 479  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 480  *      the last and the first frames arrived and all the bits are here.
 481  */
 482 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 483                           struct net_device *dev)
 484 {
 485         struct sk_buff *fp, *head = fq->q.fragments;
 486         int    payload_len;
 487         unsigned int nhoff;
 488
 489         fq_kill(fq);
 490
 491         /* Make the one we just received the head. */
 492         if (prev) {
 493                 head = prev->next;
 494                 fp = skb_clone(head, GFP_ATOMIC);
 495
 496                 if (!fp)
 497                         goto out_oom;
 498
 499                 fp->next = head->next;
 500                 prev->next = fp;
 501
 502                 skb_morph(head, fq->q.fragments);
 503                 head->next = fq->q.fragments->next;
 504
 505                 kfree_skb(fq->q.fragments);
 506                 fq->q.fragments = head;
 507         }
 508
 509         BUG_TRAP(head != NULL);
 510         BUG_TRAP(FRAG6_CB(head)->offset == 0);
 511
 512         /* Unfragmented part is taken from the first segment. */
 513         payload_len = ((head->data - skb_network_header(head)) -
 514                        sizeof(struct ipv6hdr) + fq->q.len -
 515                        sizeof(struct frag_hdr));
 516         if (payload_len > IPV6_MAXPLEN)
 517                 goto out_oversize;
 518
 519         /* Head of list must not be cloned. */
 520         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 521                 goto out_oom;
 522
 523         /* If the first fragment is fragmented itself, we split
 524          * it to two chunks: the first with data and paged part
 525          * and the second, holding only fragments. */
 526         if (skb_shinfo(head)->frag_list) {
 527                 struct sk_buff *clone;
 528                 int i, plen = 0;
 529
 530                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 531                         goto out_oom;
 532                 clone->next = head->next;
 533                 head->next = clone;
 534                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 535                 skb_shinfo(head)->frag_list = NULL;
 536                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 537                         plen += skb_shinfo(head)->frags[i].size;
 538                 clone->len = clone->data_len = head->data_len - plen;
 539                 head->data_len -= clone->len;
 540                 head->len -= clone->len;
 541                 clone->csum = 0;
 542                 clone->ip_summed = head->ip_summed;
 543                 atomic_add(clone->truesize, &ip6_frags.mem);
 544         }
 545
 546         /* We have to remove fragment header from datagram and to relocate
 547          * header in order to calculate ICV correctly. */
 548         nhoff = fq->nhoffset;
 549         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 550         memmove(head->head + sizeof(struct frag_hdr), head->head,
 551                 (head->data - head->head) - sizeof(struct frag_hdr));
 552         head->mac_header += sizeof(struct frag_hdr);
 553         head->network_header += sizeof(struct frag_hdr);
 554
 555         skb_shinfo(head)->frag_list = head->next;
 556         skb_reset_transport_header(head);
 557         skb_push(head, head->data - skb_network_header(head));
 558         atomic_sub(head->truesize, &ip6_frags.mem);
 559
 560         for (fp=head->next; fp; fp = fp->next) {
 561                 head->data_len += fp->len;
 562                 head->len += fp->len;
 563                 if (head->ip_summed != fp->ip_summed)
 564                         head->ip_summed = CHECKSUM_NONE;
 565                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 566                         head->csum = csum_add(head->csum, fp->csum);
 567                 head->truesize += fp->truesize;
 568                 atomic_sub(fp->truesize, &ip6_frags.mem);
 569         }
 570
 571         head->next = NULL;
 572         head->dev = dev;
 573         head->tstamp = fq->q.stamp;
 574         ipv6_hdr(head)->payload_len = htons(payload_len);
 575         IP6CB(head)->nhoff = nhoff;
 576
 577         /* Yes, and fold redundant checksum back. 8) */
 578         if (head->ip_summed == CHECKSUM_COMPLETE)
 579                 head->csum = csum_partial(skb_network_header(head),
 580                                           skb_network_header_len(head),
 581                                           head->csum);
 582
 583         rcu_read_lock();
 584         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 585         rcu_read_unlock();
 586         fq->q.fragments = NULL;
 587         return 1;
 588
 589 out_oversize:
 590         if (net_ratelimit())
 591                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
 592         goto out_fail;
 593 out_oom:
 594         if (net_ratelimit())
 595                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
 596 out_fail:
 597         rcu_read_lock();
 598         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 599         rcu_read_unlock();
 600         return -1;
 601 }
 602
 603 static int ipv6_frag_rcv(struct sk_buff *skb)
 604 {
 605         struct frag_hdr *fhdr;
 606         struct frag_queue *fq;
 607         struct ipv6hdr *hdr = ipv6_hdr(skb);
 608
 609         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS);
 610
 611         /* Jumbo payload inhibits frag. header */
 612         if (hdr->payload_len==0) {
 613                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 614                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 615                                   skb_network_header_len(skb));
 616                 return -1;
 617         }
 618         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 619                                  sizeof(struct frag_hdr)))) {
 620                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 621                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 622                                   skb_network_header_len(skb));
 623                 return -1;
 624         }
 625
 626         hdr = ipv6_hdr(skb);
 627         fhdr = (struct frag_hdr *)skb_transport_header(skb);
 628
 629         if (!(fhdr->frag_off & htons(0xFFF9))) {
 630                 /* It is not a fragmented frame */
 631                 skb->transport_header += sizeof(struct frag_hdr);
 632                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS);
 633
 634                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 635                 return 1;
 636         }
 637
 638         if (atomic_read(&ip6_frags.mem) > ip6_frags_ctl.high_thresh)
 639                 ip6_evictor(ip6_dst_idev(skb->dst));
 640
 641         if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr,
 642                           ip6_dst_idev(skb->dst))) != NULL) {
 643                 int ret;
 644
 645                 spin_lock(&fq->q.lock);
 646
 647                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 648
 649                 spin_unlock(&fq->q.lock);
 650                 fq_put(fq);
 651                 return ret;
 652         }
 653
 654         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 655         kfree_skb(skb);
 656         return -1;
 657 }
 658
 659 static struct inet6_protocol frag_protocol =
 660 {
 661         .handler        =       ipv6_frag_rcv,
 662         .flags          =       INET6_PROTO_NOPOLICY,
 663 };
 664
 665 void __init ipv6_frag_init(void)
 666 {
 667         if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0)
 668                 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n");
 669
 670         ip6_frags.ctl = &ip6_frags_ctl;
 671         ip6_frags.hashfn = ip6_hashfn;
 672         ip6_frags.constructor = ip6_frag_init;
 673         ip6_frags.destructor = ip6_frag_free;
 674         ip6_frags.skb_free = NULL;
 675         ip6_frags.qsize = sizeof(struct frag_queue);
 676         ip6_frags.equal = ip6_frag_equal;
 677         ip6_frags.frag_expire = ip6_frag_expire;
 678         inet_frags_init(&ip6_frags);
 679 }