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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 static void ip6_frag_free(struct inet_frag_queue *fq)
 168 {
 169         kfree(container_of(fq, struct frag_queue, q));
 170 }
 171
 172 static inline struct frag_queue *frag_alloc_queue(void)
 173 {
 174         struct inet_frag_queue *q;
 175
 176         q = inet_frag_alloc(&ip6_frags);
 177         return q ? container_of(q, struct frag_queue, q) : NULL;
 178 }
 179
 180 /* Destruction primitives. */
 181
 182 static __inline__ void fq_put(struct frag_queue *fq)
 183 {
 184         inet_frag_put(&fq->q, &ip6_frags);
 185 }
 186
 187 /* Kill fq entry. It is not destroyed immediately,
 188  * because caller (and someone more) holds reference count.
 189  */
 190 static __inline__ void fq_kill(struct frag_queue *fq)
 191 {
 192         inet_frag_kill(&fq->q, &ip6_frags);
 193 }
 194
 195 static void ip6_evictor(struct inet6_dev *idev)
 196 {
 197         int evicted;
 198
 199         evicted = inet_frag_evictor(&ip6_frags);
 200         if (evicted)
 201                 IP6_ADD_STATS_BH(idev, IPSTATS_MIB_REASMFAILS, evicted);
 202 }
 203
 204 static void ip6_frag_expire(unsigned long data)
 205 {
 206         struct frag_queue *fq;
 207         struct net_device *dev = NULL;
 208
 209         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 210
 211         spin_lock(&fq->q.lock);
 212
 213         if (fq->q.last_in & COMPLETE)
 214                 goto out;
 215
 216         fq_kill(fq);
 217
 218         dev = dev_get_by_index(&init_net, fq->iif);
 219         if (!dev)
 220                 goto out;
 221
 222         rcu_read_lock();
 223         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 224         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 225         rcu_read_unlock();
 226
 227         /* Don't send error if the first segment did not arrive. */
 228         if (!(fq->q.last_in&FIRST_IN) || !fq->q.fragments)
 229                 goto out;
 230
 231         /*
 232            But use as source device on which LAST ARRIVED
 233            segment was received. And do not use fq->dev
 234            pointer directly, device might already disappeared.
 235          */
 236         fq->q.fragments->dev = dev;
 237         icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
 238 out:
 239         if (dev)
 240                 dev_put(dev);
 241         spin_unlock(&fq->q.lock);
 242         fq_put(fq);
 243 }
 244
 245 /* Creation primitives. */
 246
 247
 248 static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in,
 249                 unsigned int hash)
 250 {
 251         struct inet_frag_queue *q;
 252
 253         q = inet_frag_intern(&fq_in->q, &ip6_frags, hash);
 254         return container_of(q, struct frag_queue, q);
 255 }
 256
 257
 258 static struct frag_queue *
 259 ip6_frag_create(__be32 id, struct in6_addr *src, struct in6_addr *dst,
 260                 struct inet6_dev *idev, unsigned int hash)
 261 {
 262         struct frag_queue *fq;
 263
 264         if ((fq = frag_alloc_queue()) == NULL)
 265                 goto oom;
 266
 267         fq->id = id;
 268         ipv6_addr_copy(&fq->saddr, src);
 269         ipv6_addr_copy(&fq->daddr, dst);
 270
 271         return ip6_frag_intern(fq, hash);
 272
 273 oom:
 274         IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS);
 275         return NULL;
 276 }
 277
 278 static __inline__ struct frag_queue *
 279 fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst,
 280         struct inet6_dev *idev)
 281 {
 282         struct frag_queue *fq;
 283         struct hlist_node *n;
 284         unsigned int hash;
 285
 286         read_lock(&ip6_frags.lock);
 287         hash = ip6qhashfn(id, src, dst);
 288         hlist_for_each_entry(fq, n, &ip6_frags.hash[hash], q.list) {
 289                 if (fq->id == id &&
 290                     ipv6_addr_equal(src, &fq->saddr) &&
 291                     ipv6_addr_equal(dst, &fq->daddr)) {
 292                         atomic_inc(&fq->q.refcnt);
 293                         read_unlock(&ip6_frags.lock);
 294                         return fq;
 295                 }
 296         }
 297         read_unlock(&ip6_frags.lock);
 298
 299         return ip6_frag_create(id, src, dst, idev, hash);
 300 }
 301
 302
 303 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 304                            struct frag_hdr *fhdr, int nhoff)
 305 {
 306         struct sk_buff *prev, *next;
 307         struct net_device *dev;
 308         int offset, end;
 309
 310         if (fq->q.last_in & COMPLETE)
 311                 goto err;
 312
 313         offset = ntohs(fhdr->frag_off) & ~0x7;
 314         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 315                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 316
 317         if ((unsigned int)end > IPV6_MAXPLEN) {
 318                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 319                                  IPSTATS_MIB_INHDRERRORS);
 320                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 321                                   ((u8 *)&fhdr->frag_off -
 322                                    skb_network_header(skb)));
 323                 return -1;
 324         }
 325
 326         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 327                 const unsigned char *nh = skb_network_header(skb);
 328                 skb->csum = csum_sub(skb->csum,
 329                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 330                                                   0));
 331         }
 332
 333         /* Is this the final fragment? */
 334         if (!(fhdr->frag_off & htons(IP6_MF))) {
 335                 /* If we already have some bits beyond end
 336                  * or have different end, the segment is corrupted.
 337                  */
 338                 if (end < fq->q.len ||
 339                     ((fq->q.last_in & LAST_IN) && end != fq->q.len))
 340                         goto err;
 341                 fq->q.last_in |= LAST_IN;
 342                 fq->q.len = end;
 343         } else {
 344                 /* Check if the fragment is rounded to 8 bytes.
 345                  * Required by the RFC.
 346                  */
 347                 if (end & 0x7) {
 348                         /* RFC2460 says always send parameter problem in
 349                          * this case. -DaveM
 350                          */
 351                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 352                                          IPSTATS_MIB_INHDRERRORS);
 353                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 354                                           offsetof(struct ipv6hdr, payload_len));
 355                         return -1;
 356                 }
 357                 if (end > fq->q.len) {
 358                         /* Some bits beyond end -> corruption. */
 359                         if (fq->q.last_in & LAST_IN)
 360                                 goto err;
 361                         fq->q.len = end;
 362                 }
 363         }
 364
 365         if (end == offset)
 366                 goto err;
 367
 368         /* Point into the IP datagram 'data' part. */
 369         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 370                 goto err;
 371
 372         if (pskb_trim_rcsum(skb, end - offset))
 373                 goto err;
 374
 375         /* Find out which fragments are in front and at the back of us
 376          * in the chain of fragments so far.  We must know where to put
 377          * this fragment, right?
 378          */
 379         prev = NULL;
 380         for(next = fq->q.fragments; next != NULL; next = next->next) {
 381                 if (FRAG6_CB(next)->offset >= offset)
 382                         break;  /* bingo! */
 383                 prev = next;
 384         }
 385
 386         /* We found where to put this one.  Check for overlap with
 387          * preceding fragment, and, if needed, align things so that
 388          * any overlaps are eliminated.
 389          */
 390         if (prev) {
 391                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
 392
 393                 if (i > 0) {
 394                         offset += i;
 395                         if (end <= offset)
 396                                 goto err;
 397                         if (!pskb_pull(skb, i))
 398                                 goto err;
 399                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 400                                 skb->ip_summed = CHECKSUM_NONE;
 401                 }
 402         }
 403
 404         /* Look for overlap with succeeding segments.
 405          * If we can merge fragments, do it.
 406          */
 407         while (next && FRAG6_CB(next)->offset < end) {
 408                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
 409
 410                 if (i < next->len) {
 411                         /* Eat head of the next overlapped fragment
 412                          * and leave the loop. The next ones cannot overlap.
 413                          */
 414                         if (!pskb_pull(next, i))
 415                                 goto err;
 416                         FRAG6_CB(next)->offset += i;    /* next fragment */
 417                         fq->q.meat -= i;
 418                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 419                                 next->ip_summed = CHECKSUM_NONE;
 420                         break;
 421                 } else {
 422                         struct sk_buff *free_it = next;
 423
 424                         /* Old fragment is completely overridden with
 425                          * new one drop it.
 426                          */
 427                         next = next->next;
 428
 429                         if (prev)
 430                                 prev->next = next;
 431                         else
 432                                 fq->q.fragments = next;
 433
 434                         fq->q.meat -= free_it->len;
 435                         frag_kfree_skb(free_it, NULL);
 436                 }
 437         }
 438
 439         FRAG6_CB(skb)->offset = offset;
 440
 441         /* Insert this fragment in the chain of fragments. */
 442         skb->next = next;
 443         if (prev)
 444                 prev->next = skb;
 445         else
 446                 fq->q.fragments = skb;
 447
 448         dev = skb->dev;
 449         if (dev) {
 450                 fq->iif = dev->ifindex;
 451                 skb->dev = NULL;
 452         }
 453         fq->q.stamp = skb->tstamp;
 454         fq->q.meat += skb->len;
 455         atomic_add(skb->truesize, &ip6_frags.mem);
 456
 457         /* The first fragment.
 458          * nhoffset is obtained from the first fragment, of course.
 459          */
 460         if (offset == 0) {
 461                 fq->nhoffset = nhoff;
 462                 fq->q.last_in |= FIRST_IN;
 463         }
 464
 465         if (fq->q.last_in == (FIRST_IN | LAST_IN) && fq->q.meat == fq->q.len)
 466                 return ip6_frag_reasm(fq, prev, dev);
 467
 468         write_lock(&ip6_frags.lock);
 469         list_move_tail(&fq->q.lru_list, &ip6_frags.lru_list);
 470         write_unlock(&ip6_frags.lock);
 471         return -1;
 472
 473 err:
 474         IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 475         kfree_skb(skb);
 476         return -1;
 477 }
 478
 479 /*
 480  *      Check if this packet is complete.
 481  *      Returns NULL on failure by any reason, and pointer
 482  *      to current nexthdr field in reassembled frame.
 483  *
 484  *      It is called with locked fq, and caller must check that
 485  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 486  *      the last and the first frames arrived and all the bits are here.
 487  */
 488 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 489                           struct net_device *dev)
 490 {
 491         struct sk_buff *fp, *head = fq->q.fragments;
 492         int    payload_len;
 493         unsigned int nhoff;
 494
 495         fq_kill(fq);
 496
 497         /* Make the one we just received the head. */
 498         if (prev) {
 499                 head = prev->next;
 500                 fp = skb_clone(head, GFP_ATOMIC);
 501
 502                 if (!fp)
 503                         goto out_oom;
 504
 505                 fp->next = head->next;
 506                 prev->next = fp;
 507
 508                 skb_morph(head, fq->q.fragments);
 509                 head->next = fq->q.fragments->next;
 510
 511                 kfree_skb(fq->q.fragments);
 512                 fq->q.fragments = head;
 513         }
 514
 515         BUG_TRAP(head != NULL);
 516         BUG_TRAP(FRAG6_CB(head)->offset == 0);
 517
 518         /* Unfragmented part is taken from the first segment. */
 519         payload_len = ((head->data - skb_network_header(head)) -
 520                        sizeof(struct ipv6hdr) + fq->q.len -
 521                        sizeof(struct frag_hdr));
 522         if (payload_len > IPV6_MAXPLEN)
 523                 goto out_oversize;
 524
 525         /* Head of list must not be cloned. */
 526         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 527                 goto out_oom;
 528
 529         /* If the first fragment is fragmented itself, we split
 530          * it to two chunks: the first with data and paged part
 531          * and the second, holding only fragments. */
 532         if (skb_shinfo(head)->frag_list) {
 533                 struct sk_buff *clone;
 534                 int i, plen = 0;
 535
 536                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 537                         goto out_oom;
 538                 clone->next = head->next;
 539                 head->next = clone;
 540                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 541                 skb_shinfo(head)->frag_list = NULL;
 542                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 543                         plen += skb_shinfo(head)->frags[i].size;
 544                 clone->len = clone->data_len = head->data_len - plen;
 545                 head->data_len -= clone->len;
 546                 head->len -= clone->len;
 547                 clone->csum = 0;
 548                 clone->ip_summed = head->ip_summed;
 549                 atomic_add(clone->truesize, &ip6_frags.mem);
 550         }
 551
 552         /* We have to remove fragment header from datagram and to relocate
 553          * header in order to calculate ICV correctly. */
 554         nhoff = fq->nhoffset;
 555         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 556         memmove(head->head + sizeof(struct frag_hdr), head->head,
 557                 (head->data - head->head) - sizeof(struct frag_hdr));
 558         head->mac_header += sizeof(struct frag_hdr);
 559         head->network_header += sizeof(struct frag_hdr);
 560
 561         skb_shinfo(head)->frag_list = head->next;
 562         skb_reset_transport_header(head);
 563         skb_push(head, head->data - skb_network_header(head));
 564         atomic_sub(head->truesize, &ip6_frags.mem);
 565
 566         for (fp=head->next; fp; fp = fp->next) {
 567                 head->data_len += fp->len;
 568                 head->len += fp->len;
 569                 if (head->ip_summed != fp->ip_summed)
 570                         head->ip_summed = CHECKSUM_NONE;
 571                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 572                         head->csum = csum_add(head->csum, fp->csum);
 573                 head->truesize += fp->truesize;
 574                 atomic_sub(fp->truesize, &ip6_frags.mem);
 575         }
 576
 577         head->next = NULL;
 578         head->dev = dev;
 579         head->tstamp = fq->q.stamp;
 580         ipv6_hdr(head)->payload_len = htons(payload_len);
 581         IP6CB(head)->nhoff = nhoff;
 582
 583         /* Yes, and fold redundant checksum back. 8) */
 584         if (head->ip_summed == CHECKSUM_COMPLETE)
 585                 head->csum = csum_partial(skb_network_header(head),
 586                                           skb_network_header_len(head),
 587                                           head->csum);
 588
 589         rcu_read_lock();
 590         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 591         rcu_read_unlock();
 592         fq->q.fragments = NULL;
 593         return 1;
 594
 595 out_oversize:
 596         if (net_ratelimit())
 597                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
 598         goto out_fail;
 599 out_oom:
 600         if (net_ratelimit())
 601                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
 602 out_fail:
 603         rcu_read_lock();
 604         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 605         rcu_read_unlock();
 606         return -1;
 607 }
 608
 609 static int ipv6_frag_rcv(struct sk_buff *skb)
 610 {
 611         struct frag_hdr *fhdr;
 612         struct frag_queue *fq;
 613         struct ipv6hdr *hdr = ipv6_hdr(skb);
 614
 615         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS);
 616
 617         /* Jumbo payload inhibits frag. header */
 618         if (hdr->payload_len==0) {
 619                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 620                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 621                                   skb_network_header_len(skb));
 622                 return -1;
 623         }
 624         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 625                                  sizeof(struct frag_hdr)))) {
 626                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 627                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 628                                   skb_network_header_len(skb));
 629                 return -1;
 630         }
 631
 632         hdr = ipv6_hdr(skb);
 633         fhdr = (struct frag_hdr *)skb_transport_header(skb);
 634
 635         if (!(fhdr->frag_off & htons(0xFFF9))) {
 636                 /* It is not a fragmented frame */
 637                 skb->transport_header += sizeof(struct frag_hdr);
 638                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS);
 639
 640                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 641                 return 1;
 642         }
 643
 644         if (atomic_read(&ip6_frags.mem) > ip6_frags_ctl.high_thresh)
 645                 ip6_evictor(ip6_dst_idev(skb->dst));
 646
 647         if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr,
 648                           ip6_dst_idev(skb->dst))) != NULL) {
 649                 int ret;
 650
 651                 spin_lock(&fq->q.lock);
 652
 653                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 654
 655                 spin_unlock(&fq->q.lock);
 656                 fq_put(fq);
 657                 return ret;
 658         }
 659
 660         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 661         kfree_skb(skb);
 662         return -1;
 663 }
 664
 665 static struct inet6_protocol frag_protocol =
 666 {
 667         .handler        =       ipv6_frag_rcv,
 668         .flags          =       INET6_PROTO_NOPOLICY,
 669 };
 670
 671 void __init ipv6_frag_init(void)
 672 {
 673         if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0)
 674                 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n");
 675
 676         ip6_frags.ctl = &ip6_frags_ctl;
 677         ip6_frags.hashfn = ip6_hashfn;
 678         ip6_frags.destructor = ip6_frag_free;
 679         ip6_frags.skb_free = NULL;
 680         ip6_frags.qsize = sizeof(struct frag_queue);
 681         ip6_frags.equal = ip6_frag_equal;
 682         ip6_frags.frag_expire = ip6_frag_expire;
 683         inet_frags_init(&ip6_frags);
 684 }