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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 /* Memory Tracking Functions. */
 147 static inline void frag_kfree_skb(struct sk_buff *skb, int *work)
 148 {
 149         if (work)
 150                 *work -= skb->truesize;
 151         atomic_sub(skb->truesize, &ip6_frags.mem);
 152         kfree_skb(skb);
 153 }
 154
 155 static void ip6_frag_free(struct inet_frag_queue *fq)
 156 {
 157         kfree(container_of(fq, struct frag_queue, q));
 158 }
 159
 160 static inline struct frag_queue *frag_alloc_queue(void)
 161 {
 162         struct frag_queue *fq = kzalloc(sizeof(struct frag_queue), GFP_ATOMIC);
 163
 164         if(!fq)
 165                 return NULL;
 166         atomic_add(sizeof(struct frag_queue), &ip6_frags.mem);
 167         return fq;
 168 }
 169
 170 /* Destruction primitives. */
 171
 172 static __inline__ void fq_put(struct frag_queue *fq, int *work)
 173 {
 174         if (atomic_dec_and_test(&fq->q.refcnt))
 175                 inet_frag_destroy(&fq->q, &ip6_frags, work);
 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         struct frag_queue *fq;
 189         struct list_head *tmp;
 190         int work;
 191
 192         work = atomic_read(&ip6_frags.mem) - ip6_frags_ctl.low_thresh;
 193         if (work <= 0)
 194                 return;
 195
 196         while(work > 0) {
 197                 read_lock(&ip6_frags.lock);
 198                 if (list_empty(&ip6_frags.lru_list)) {
 199                         read_unlock(&ip6_frags.lock);
 200                         return;
 201                 }
 202                 tmp = ip6_frags.lru_list.next;
 203                 fq = list_entry(tmp, struct frag_queue, q.lru_list);
 204                 atomic_inc(&fq->q.refcnt);
 205                 read_unlock(&ip6_frags.lock);
 206
 207                 spin_lock(&fq->q.lock);
 208                 if (!(fq->q.last_in&COMPLETE))
 209                         fq_kill(fq);
 210                 spin_unlock(&fq->q.lock);
 211
 212                 fq_put(fq, &work);
 213                 IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS);
 214         }
 215 }
 216
 217 static void ip6_frag_expire(unsigned long data)
 218 {
 219         struct frag_queue *fq = (struct frag_queue *) data;
 220         struct net_device *dev = NULL;
 221
 222         spin_lock(&fq->q.lock);
 223
 224         if (fq->q.last_in & COMPLETE)
 225                 goto out;
 226
 227         fq_kill(fq);
 228
 229         dev = dev_get_by_index(&init_net, fq->iif);
 230         if (!dev)
 231                 goto out;
 232
 233         rcu_read_lock();
 234         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 235         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 236         rcu_read_unlock();
 237
 238         /* Don't send error if the first segment did not arrive. */
 239         if (!(fq->q.last_in&FIRST_IN) || !fq->q.fragments)
 240                 goto out;
 241
 242         /*
 243            But use as source device on which LAST ARRIVED
 244            segment was received. And do not use fq->dev
 245            pointer directly, device might already disappeared.
 246          */
 247         fq->q.fragments->dev = dev;
 248         icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
 249 out:
 250         if (dev)
 251                 dev_put(dev);
 252         spin_unlock(&fq->q.lock);
 253         fq_put(fq, NULL);
 254 }
 255
 256 /* Creation primitives. */
 257
 258
 259 static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in)
 260 {
 261         struct frag_queue *fq;
 262         unsigned int hash;
 263 #ifdef CONFIG_SMP
 264         struct hlist_node *n;
 265 #endif
 266
 267         write_lock(&ip6_frags.lock);
 268         hash = ip6qhashfn(fq_in->id, &fq_in->saddr, &fq_in->daddr);
 269 #ifdef CONFIG_SMP
 270         hlist_for_each_entry(fq, n, &ip6_frags.hash[hash], q.list) {
 271                 if (fq->id == fq_in->id &&
 272                     ipv6_addr_equal(&fq_in->saddr, &fq->saddr) &&
 273                     ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) {
 274                         atomic_inc(&fq->q.refcnt);
 275                         write_unlock(&ip6_frags.lock);
 276                         fq_in->q.last_in |= COMPLETE;
 277                         fq_put(fq_in, NULL);
 278                         return fq;
 279                 }
 280         }
 281 #endif
 282         fq = fq_in;
 283
 284         if (!mod_timer(&fq->q.timer, jiffies + ip6_frags_ctl.timeout))
 285                 atomic_inc(&fq->q.refcnt);
 286
 287         atomic_inc(&fq->q.refcnt);
 288         hlist_add_head(&fq->q.list, &ip6_frags.hash[hash]);
 289         INIT_LIST_HEAD(&fq->q.lru_list);
 290         list_add_tail(&fq->q.lru_list, &ip6_frags.lru_list);
 291         ip6_frags.nqueues++;
 292         write_unlock(&ip6_frags.lock);
 293         return fq;
 294 }
 295
 296
 297 static struct frag_queue *
 298 ip6_frag_create(__be32 id, struct in6_addr *src, struct in6_addr *dst,
 299                 struct inet6_dev *idev)
 300 {
 301         struct frag_queue *fq;
 302
 303         if ((fq = frag_alloc_queue()) == NULL)
 304                 goto oom;
 305
 306         fq->id = id;
 307         ipv6_addr_copy(&fq->saddr, src);
 308         ipv6_addr_copy(&fq->daddr, dst);
 309
 310         init_timer(&fq->q.timer);
 311         fq->q.timer.function = ip6_frag_expire;
 312         fq->q.timer.data = (long) fq;
 313         spin_lock_init(&fq->q.lock);
 314         atomic_set(&fq->q.refcnt, 1);
 315
 316         return ip6_frag_intern(fq);
 317
 318 oom:
 319         IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS);
 320         return NULL;
 321 }
 322
 323 static __inline__ struct frag_queue *
 324 fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst,
 325         struct inet6_dev *idev)
 326 {
 327         struct frag_queue *fq;
 328         struct hlist_node *n;
 329         unsigned int hash;
 330
 331         read_lock(&ip6_frags.lock);
 332         hash = ip6qhashfn(id, src, dst);
 333         hlist_for_each_entry(fq, n, &ip6_frags.hash[hash], q.list) {
 334                 if (fq->id == id &&
 335                     ipv6_addr_equal(src, &fq->saddr) &&
 336                     ipv6_addr_equal(dst, &fq->daddr)) {
 337                         atomic_inc(&fq->q.refcnt);
 338                         read_unlock(&ip6_frags.lock);
 339                         return fq;
 340                 }
 341         }
 342         read_unlock(&ip6_frags.lock);
 343
 344         return ip6_frag_create(id, src, dst, idev);
 345 }
 346
 347
 348 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 349                            struct frag_hdr *fhdr, int nhoff)
 350 {
 351         struct sk_buff *prev, *next;
 352         struct net_device *dev;
 353         int offset, end;
 354
 355         if (fq->q.last_in & COMPLETE)
 356                 goto err;
 357
 358         offset = ntohs(fhdr->frag_off) & ~0x7;
 359         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 360                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 361
 362         if ((unsigned int)end > IPV6_MAXPLEN) {
 363                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 364                                  IPSTATS_MIB_INHDRERRORS);
 365                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 366                                   ((u8 *)&fhdr->frag_off -
 367                                    skb_network_header(skb)));
 368                 return -1;
 369         }
 370
 371         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 372                 const unsigned char *nh = skb_network_header(skb);
 373                 skb->csum = csum_sub(skb->csum,
 374                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 375                                                   0));
 376         }
 377
 378         /* Is this the final fragment? */
 379         if (!(fhdr->frag_off & htons(IP6_MF))) {
 380                 /* If we already have some bits beyond end
 381                  * or have different end, the segment is corrupted.
 382                  */
 383                 if (end < fq->q.len ||
 384                     ((fq->q.last_in & LAST_IN) && end != fq->q.len))
 385                         goto err;
 386                 fq->q.last_in |= LAST_IN;
 387                 fq->q.len = end;
 388         } else {
 389                 /* Check if the fragment is rounded to 8 bytes.
 390                  * Required by the RFC.
 391                  */
 392                 if (end & 0x7) {
 393                         /* RFC2460 says always send parameter problem in
 394                          * this case. -DaveM
 395                          */
 396                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 397                                          IPSTATS_MIB_INHDRERRORS);
 398                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 399                                           offsetof(struct ipv6hdr, payload_len));
 400                         return -1;
 401                 }
 402                 if (end > fq->q.len) {
 403                         /* Some bits beyond end -> corruption. */
 404                         if (fq->q.last_in & LAST_IN)
 405                                 goto err;
 406                         fq->q.len = end;
 407                 }
 408         }
 409
 410         if (end == offset)
 411                 goto err;
 412
 413         /* Point into the IP datagram 'data' part. */
 414         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 415                 goto err;
 416
 417         if (pskb_trim_rcsum(skb, end - offset))
 418                 goto err;
 419
 420         /* Find out which fragments are in front and at the back of us
 421          * in the chain of fragments so far.  We must know where to put
 422          * this fragment, right?
 423          */
 424         prev = NULL;
 425         for(next = fq->q.fragments; next != NULL; next = next->next) {
 426                 if (FRAG6_CB(next)->offset >= offset)
 427                         break;  /* bingo! */
 428                 prev = next;
 429         }
 430
 431         /* We found where to put this one.  Check for overlap with
 432          * preceding fragment, and, if needed, align things so that
 433          * any overlaps are eliminated.
 434          */
 435         if (prev) {
 436                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
 437
 438                 if (i > 0) {
 439                         offset += i;
 440                         if (end <= offset)
 441                                 goto err;
 442                         if (!pskb_pull(skb, i))
 443                                 goto err;
 444                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 445                                 skb->ip_summed = CHECKSUM_NONE;
 446                 }
 447         }
 448
 449         /* Look for overlap with succeeding segments.
 450          * If we can merge fragments, do it.
 451          */
 452         while (next && FRAG6_CB(next)->offset < end) {
 453                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
 454
 455                 if (i < next->len) {
 456                         /* Eat head of the next overlapped fragment
 457                          * and leave the loop. The next ones cannot overlap.
 458                          */
 459                         if (!pskb_pull(next, i))
 460                                 goto err;
 461                         FRAG6_CB(next)->offset += i;    /* next fragment */
 462                         fq->q.meat -= i;
 463                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 464                                 next->ip_summed = CHECKSUM_NONE;
 465                         break;
 466                 } else {
 467                         struct sk_buff *free_it = next;
 468
 469                         /* Old fragment is completely overridden with
 470                          * new one drop it.
 471                          */
 472                         next = next->next;
 473
 474                         if (prev)
 475                                 prev->next = next;
 476                         else
 477                                 fq->q.fragments = next;
 478
 479                         fq->q.meat -= free_it->len;
 480                         frag_kfree_skb(free_it, NULL);
 481                 }
 482         }
 483
 484         FRAG6_CB(skb)->offset = offset;
 485
 486         /* Insert this fragment in the chain of fragments. */
 487         skb->next = next;
 488         if (prev)
 489                 prev->next = skb;
 490         else
 491                 fq->q.fragments = skb;
 492
 493         dev = skb->dev;
 494         if (dev) {
 495                 fq->iif = dev->ifindex;
 496                 skb->dev = NULL;
 497         }
 498         fq->q.stamp = skb->tstamp;
 499         fq->q.meat += skb->len;
 500         atomic_add(skb->truesize, &ip6_frags.mem);
 501
 502         /* The first fragment.
 503          * nhoffset is obtained from the first fragment, of course.
 504          */
 505         if (offset == 0) {
 506                 fq->nhoffset = nhoff;
 507                 fq->q.last_in |= FIRST_IN;
 508         }
 509
 510         if (fq->q.last_in == (FIRST_IN | LAST_IN) && fq->q.meat == fq->q.len)
 511                 return ip6_frag_reasm(fq, prev, dev);
 512
 513         write_lock(&ip6_frags.lock);
 514         list_move_tail(&fq->q.lru_list, &ip6_frags.lru_list);
 515         write_unlock(&ip6_frags.lock);
 516         return -1;
 517
 518 err:
 519         IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 520         kfree_skb(skb);
 521         return -1;
 522 }
 523
 524 /*
 525  *      Check if this packet is complete.
 526  *      Returns NULL on failure by any reason, and pointer
 527  *      to current nexthdr field in reassembled frame.
 528  *
 529  *      It is called with locked fq, and caller must check that
 530  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 531  *      the last and the first frames arrived and all the bits are here.
 532  */
 533 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 534                           struct net_device *dev)
 535 {
 536         struct sk_buff *fp, *head = fq->q.fragments;
 537         int    payload_len;
 538         unsigned int nhoff;
 539
 540         fq_kill(fq);
 541
 542         /* Make the one we just received the head. */
 543         if (prev) {
 544                 head = prev->next;
 545                 fp = skb_clone(head, GFP_ATOMIC);
 546
 547                 if (!fp)
 548                         goto out_oom;
 549
 550                 fp->next = head->next;
 551                 prev->next = fp;
 552
 553                 skb_morph(head, fq->q.fragments);
 554                 head->next = fq->q.fragments->next;
 555
 556                 kfree_skb(fq->q.fragments);
 557                 fq->q.fragments = head;
 558         }
 559
 560         BUG_TRAP(head != NULL);
 561         BUG_TRAP(FRAG6_CB(head)->offset == 0);
 562
 563         /* Unfragmented part is taken from the first segment. */
 564         payload_len = ((head->data - skb_network_header(head)) -
 565                        sizeof(struct ipv6hdr) + fq->q.len -
 566                        sizeof(struct frag_hdr));
 567         if (payload_len > IPV6_MAXPLEN)
 568                 goto out_oversize;
 569
 570         /* Head of list must not be cloned. */
 571         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 572                 goto out_oom;
 573
 574         /* If the first fragment is fragmented itself, we split
 575          * it to two chunks: the first with data and paged part
 576          * and the second, holding only fragments. */
 577         if (skb_shinfo(head)->frag_list) {
 578                 struct sk_buff *clone;
 579                 int i, plen = 0;
 580
 581                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 582                         goto out_oom;
 583                 clone->next = head->next;
 584                 head->next = clone;
 585                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 586                 skb_shinfo(head)->frag_list = NULL;
 587                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 588                         plen += skb_shinfo(head)->frags[i].size;
 589                 clone->len = clone->data_len = head->data_len - plen;
 590                 head->data_len -= clone->len;
 591                 head->len -= clone->len;
 592                 clone->csum = 0;
 593                 clone->ip_summed = head->ip_summed;
 594                 atomic_add(clone->truesize, &ip6_frags.mem);
 595         }
 596
 597         /* We have to remove fragment header from datagram and to relocate
 598          * header in order to calculate ICV correctly. */
 599         nhoff = fq->nhoffset;
 600         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 601         memmove(head->head + sizeof(struct frag_hdr), head->head,
 602                 (head->data - head->head) - sizeof(struct frag_hdr));
 603         head->mac_header += sizeof(struct frag_hdr);
 604         head->network_header += sizeof(struct frag_hdr);
 605
 606         skb_shinfo(head)->frag_list = head->next;
 607         skb_reset_transport_header(head);
 608         skb_push(head, head->data - skb_network_header(head));
 609         atomic_sub(head->truesize, &ip6_frags.mem);
 610
 611         for (fp=head->next; fp; fp = fp->next) {
 612                 head->data_len += fp->len;
 613                 head->len += fp->len;
 614                 if (head->ip_summed != fp->ip_summed)
 615                         head->ip_summed = CHECKSUM_NONE;
 616                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 617                         head->csum = csum_add(head->csum, fp->csum);
 618                 head->truesize += fp->truesize;
 619                 atomic_sub(fp->truesize, &ip6_frags.mem);
 620         }
 621
 622         head->next = NULL;
 623         head->dev = dev;
 624         head->tstamp = fq->q.stamp;
 625         ipv6_hdr(head)->payload_len = htons(payload_len);
 626         IP6CB(head)->nhoff = nhoff;
 627
 628         /* Yes, and fold redundant checksum back. 8) */
 629         if (head->ip_summed == CHECKSUM_COMPLETE)
 630                 head->csum = csum_partial(skb_network_header(head),
 631                                           skb_network_header_len(head),
 632                                           head->csum);
 633
 634         rcu_read_lock();
 635         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 636         rcu_read_unlock();
 637         fq->q.fragments = NULL;
 638         return 1;
 639
 640 out_oversize:
 641         if (net_ratelimit())
 642                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
 643         goto out_fail;
 644 out_oom:
 645         if (net_ratelimit())
 646                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
 647 out_fail:
 648         rcu_read_lock();
 649         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 650         rcu_read_unlock();
 651         return -1;
 652 }
 653
 654 static int ipv6_frag_rcv(struct sk_buff **skbp)
 655 {
 656         struct sk_buff *skb = *skbp;
 657         struct frag_hdr *fhdr;
 658         struct frag_queue *fq;
 659         struct ipv6hdr *hdr = ipv6_hdr(skb);
 660
 661         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS);
 662
 663         /* Jumbo payload inhibits frag. header */
 664         if (hdr->payload_len==0) {
 665                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 666                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 667                                   skb_network_header_len(skb));
 668                 return -1;
 669         }
 670         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 671                                  sizeof(struct frag_hdr)))) {
 672                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 673                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 674                                   skb_network_header_len(skb));
 675                 return -1;
 676         }
 677
 678         hdr = ipv6_hdr(skb);
 679         fhdr = (struct frag_hdr *)skb_transport_header(skb);
 680
 681         if (!(fhdr->frag_off & htons(0xFFF9))) {
 682                 /* It is not a fragmented frame */
 683                 skb->transport_header += sizeof(struct frag_hdr);
 684                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS);
 685
 686                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 687                 return 1;
 688         }
 689
 690         if (atomic_read(&ip6_frags.mem) > ip6_frags_ctl.high_thresh)
 691                 ip6_evictor(ip6_dst_idev(skb->dst));
 692
 693         if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr,
 694                           ip6_dst_idev(skb->dst))) != NULL) {
 695                 int ret;
 696
 697                 spin_lock(&fq->q.lock);
 698
 699                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 700
 701                 spin_unlock(&fq->q.lock);
 702                 fq_put(fq, NULL);
 703                 return ret;
 704         }
 705
 706         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 707         kfree_skb(skb);
 708         return -1;
 709 }
 710
 711 static struct inet6_protocol frag_protocol =
 712 {
 713         .handler        =       ipv6_frag_rcv,
 714         .flags          =       INET6_PROTO_NOPOLICY,
 715 };
 716
 717 void __init ipv6_frag_init(void)
 718 {
 719         if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0)
 720                 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n");
 721
 722         ip6_frags.ctl = &ip6_frags_ctl;
 723         ip6_frags.hashfn = ip6_hashfn;
 724         ip6_frags.destructor = ip6_frag_free;
 725         ip6_frags.skb_free = NULL;
 726         ip6_frags.qsize = sizeof(struct frag_queue);
 727         inet_frags_init(&ip6_frags);
 728 }