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 1.1.1.1 2005/04/11 02:51:13 jack 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  */
  26 #include <linux/config.h>
  27 #include <linux/errno.h>
  28 #include <linux/types.h>
  29 #include <linux/string.h>
  30 #include <linux/socket.h>
  31 #include <linux/sockios.h>
  32 #include <linux/sched.h>
  33 #include <linux/net.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/in6.h>
  36 #include <linux/ipv6.h>
  37 #include <linux/icmpv6.h>
  38
  39 #include <net/sock.h>
  40 #include <net/snmp.h>
  41
  42 #include <net/ipv6.h>
  43 #include <net/protocol.h>
  44 #include <net/transp_v6.h>
  45 #include <net/rawv6.h>
  46 #include <net/ndisc.h>
  47 #include <net/addrconf.h>
  48
  49 int sysctl_ip6frag_high_thresh = 256*1024;
  50 int sysctl_ip6frag_low_thresh = 192*1024;
  51
  52 int sysctl_ip6frag_time = IPV6_FRAG_TIMEOUT;
  53
  54 struct ip6frag_skb_cb
  55 {
  56         struct inet6_skb_parm   h;
  57         int                     offset;
  58 };
  59
  60 #define FRAG6_CB(skb)   ((struct ip6frag_skb_cb*)((skb)->cb))
  61
  62
  63 /*
  64  *      Equivalent of ipv4 struct ipq
  65  */
  66
  67 struct frag_queue
  68 {
  69         struct frag_queue       *next;
  70
  71         __u32                   id;             /* fragment id          */
  72         struct in6_addr         saddr;
  73         struct in6_addr         daddr;
  74
  75         spinlock_t              lock;
  76         atomic_t                refcnt;
  77         struct timer_list       timer;          /* expire timer         */
  78         struct sk_buff          *fragments;
  79         int                     len;
  80         int                     meat;
  81         int                     iif;
  82         struct timeval          stamp;
  83         unsigned int            csum;
  84         __u8                    last_in;        /* has first/last segment arrived? */
  85 #define COMPLETE                4
  86 #define FIRST_IN                2
  87 #define LAST_IN                 1
  88         __u16                   nhoffset;
  89         struct frag_queue       **pprev;
  90 };
  91
  92 /* Hash table. */
  93
  94 #define IP6Q_HASHSZ     64
  95
  96 static struct frag_queue *ip6_frag_hash[IP6Q_HASHSZ];
  97 static rwlock_t ip6_frag_lock = RW_LOCK_UNLOCKED;
  98 int ip6_frag_nqueues = 0;
  99
 100 static __inline__ void __fq_unlink(struct frag_queue *fq)
 101 {
 102         if(fq->next)
 103                 fq->next->pprev = fq->pprev;
 104         *fq->pprev = fq->next;
 105         ip6_frag_nqueues--;
 106 }
 107
 108 static __inline__ void fq_unlink(struct frag_queue *fq)
 109 {
 110         write_lock(&ip6_frag_lock);
 111         __fq_unlink(fq);
 112         write_unlock(&ip6_frag_lock);
 113 }
 114
 115 static __inline__ unsigned int ip6qhashfn(u32 id, struct in6_addr *saddr,
 116                                           struct in6_addr *daddr)
 117 {
 118         unsigned int h = saddr->s6_addr32[3] ^ daddr->s6_addr32[3] ^ id;
 119
 120         h ^= (h>>16);
 121         h ^= (h>>8);
 122         return h & (IP6Q_HASHSZ - 1);
 123 }
 124
 125
 126 atomic_t ip6_frag_mem = ATOMIC_INIT(0);
 127
 128 /* Memory Tracking Functions. */
 129 extern __inline__ void frag_kfree_skb(struct sk_buff *skb)
 130 {
 131         atomic_sub(skb->truesize, &ip6_frag_mem);
 132         kfree_skb(skb);
 133 }
 134
 135 extern __inline__ void frag_free_queue(struct frag_queue *fq)
 136 {
 137         atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem);
 138         kfree(fq);
 139 }
 140
 141 extern __inline__ struct frag_queue *frag_alloc_queue(void)
 142 {
 143         struct frag_queue *fq = kmalloc(sizeof(struct frag_queue), GFP_ATOMIC);
 144
 145         if(!fq)
 146                 return NULL;
 147         atomic_add(sizeof(struct frag_queue), &ip6_frag_mem);
 148         return fq;
 149 }
 150
 151 /* Destruction primitives. */
 152
 153 /* Complete destruction of fq. */
 154 static void ip6_frag_destroy(struct frag_queue *fq)
 155 {
 156         struct sk_buff *fp;
 157
 158         BUG_TRAP(fq->last_in&COMPLETE);
 159         BUG_TRAP(del_timer(&fq->timer) == 0);
 160
 161         /* Release all fragment data. */
 162         fp = fq->fragments;
 163         while (fp) {
 164                 struct sk_buff *xp = fp->next;
 165
 166                 frag_kfree_skb(fp);
 167                 fp = xp;
 168         }
 169
 170         frag_free_queue(fq);
 171 }
 172
 173 static __inline__ void fq_put(struct frag_queue *fq)
 174 {
 175         if (atomic_dec_and_test(&fq->refcnt))
 176                 ip6_frag_destroy(fq);
 177 }
 178
 179 /* Kill fq entry. It is not destroyed immediately,
 180  * because caller (and someone more) holds reference count.
 181  */
 182 static __inline__ void fq_kill(struct frag_queue *fq)
 183 {
 184         if (del_timer(&fq->timer))
 185                 atomic_dec(&fq->refcnt);
 186
 187         if (!(fq->last_in & COMPLETE)) {
 188                 fq_unlink(fq);
 189                 atomic_dec(&fq->refcnt);
 190                 fq->last_in |= COMPLETE;
 191         }
 192 }
 193
 194 static void ip6_evictor(void)
 195 {
 196         int i, progress;
 197
 198         do {
 199                 if (atomic_read(&ip6_frag_mem) <= sysctl_ip6frag_low_thresh)
 200                         return;
 201                 progress = 0;
 202                 for (i = 0; i < IP6Q_HASHSZ; i++) {
 203                         struct frag_queue *fq;
 204                         if (ip6_frag_hash[i] == NULL)
 205                                 continue;
 206
 207                         read_lock(&ip6_frag_lock);
 208                         if ((fq = ip6_frag_hash[i]) != NULL) {
 209                                 /* find the oldest queue for this hash bucket */
 210                                 while (fq->next)
 211                                         fq = fq->next;
 212                                 atomic_inc(&fq->refcnt);
 213                                 read_unlock(&ip6_frag_lock);
 214
 215                                 spin_lock(&fq->lock);
 216                                 if (!(fq->last_in&COMPLETE))
 217                                         fq_kill(fq);
 218                                 spin_unlock(&fq->lock);
 219
 220                                 fq_put(fq);
 221                                 IP6_INC_STATS_BH(Ip6ReasmFails);
 222                                 progress = 1;
 223                                 continue;
 224                         }
 225                         read_unlock(&ip6_frag_lock);
 226                 }
 227         } while (progress);
 228 }
 229
 230 static void ip6_frag_expire(unsigned long data)
 231 {
 232         struct frag_queue *fq = (struct frag_queue *) data;
 233
 234         spin_lock(&fq->lock);
 235
 236         if (fq->last_in & COMPLETE)
 237                 goto out;
 238
 239         fq_kill(fq);
 240
 241         IP6_INC_STATS_BH(Ip6ReasmTimeout);
 242         IP6_INC_STATS_BH(Ip6ReasmFails);
 243
 244         /* Send error only if the first segment arrived. */
 245         if (fq->last_in&FIRST_IN && fq->fragments) {
 246                 struct net_device *dev = dev_get_by_index(fq->iif);
 247
 248                 /*
 249                    But use as source device on which LAST ARRIVED
 250                    segment was received. And do not use fq->dev
 251                    pointer directly, device might already disappeared.
 252                  */
 253                 if (dev) {
 254                         fq->fragments->dev = dev;
 255                         icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0,
 256                                     dev);
 257                         dev_put(dev);
 258                 }
 259         }
 260 out:
 261         spin_unlock(&fq->lock);
 262         fq_put(fq);
 263 }
 264
 265 /* Creation primitives. */
 266
 267
 268 static struct frag_queue *ip6_frag_intern(unsigned int hash,
 269                                           struct frag_queue *fq_in)
 270 {
 271         struct frag_queue *fq;
 272
 273         write_lock(&ip6_frag_lock);
 274 #ifdef CONFIG_SMP
 275         for (fq = ip6_frag_hash[hash]; fq; fq = fq->next) {
 276                 if (fq->id == fq_in->id &&
 277                     !ipv6_addr_cmp(&fq_in->saddr, &fq->saddr) &&
 278                     !ipv6_addr_cmp(&fq_in->daddr, &fq->daddr)) {
 279                         atomic_inc(&fq->refcnt);
 280                         write_unlock(&ip6_frag_lock);
 281                         fq_in->last_in |= COMPLETE;
 282                         fq_put(fq_in);
 283                         return fq;
 284                 }
 285         }
 286 #endif
 287         fq = fq_in;
 288
 289         if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time))
 290                 atomic_inc(&fq->refcnt);
 291
 292         atomic_inc(&fq->refcnt);
 293         if((fq->next = ip6_frag_hash[hash]) != NULL)
 294                 fq->next->pprev = &fq->next;
 295         ip6_frag_hash[hash] = fq;
 296         fq->pprev = &ip6_frag_hash[hash];
 297         ip6_frag_nqueues++;
 298         write_unlock(&ip6_frag_lock);
 299         return fq;
 300 }
 301
 302
 303 static struct frag_queue *
 304 ip6_frag_create(unsigned int hash, u32 id, struct in6_addr *src, struct in6_addr *dst)
 305 {
 306         struct frag_queue *fq;
 307
 308         if ((fq = frag_alloc_queue()) == NULL)
 309                 goto oom;
 310
 311         memset(fq, 0, sizeof(struct frag_queue));
 312
 313         fq->id = id;
 314         ipv6_addr_copy(&fq->saddr, src);
 315         ipv6_addr_copy(&fq->daddr, dst);
 316
 317         /* init_timer has been done by the memset */
 318         fq->timer.function = ip6_frag_expire;
 319         fq->timer.data = (long) fq;
 320         fq->lock = SPIN_LOCK_UNLOCKED;
 321         atomic_set(&fq->refcnt, 1);
 322
 323         return ip6_frag_intern(hash, fq);
 324
 325 oom:
 326         IP6_INC_STATS_BH(Ip6ReasmFails);
 327         return NULL;
 328 }
 329
 330 static __inline__ struct frag_queue *
 331 fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst)
 332 {
 333         struct frag_queue *fq;
 334         unsigned int hash = ip6qhashfn(id, src, dst);
 335
 336         read_lock(&ip6_frag_lock);
 337         for(fq = ip6_frag_hash[hash]; fq; fq = fq->next) {
 338                 if (fq->id == id &&
 339                     !ipv6_addr_cmp(src, &fq->saddr) &&
 340                     !ipv6_addr_cmp(dst, &fq->daddr)) {
 341                         atomic_inc(&fq->refcnt);
 342                         read_unlock(&ip6_frag_lock);
 343                         return fq;
 344                 }
 345         }
 346         read_unlock(&ip6_frag_lock);
 347
 348         return ip6_frag_create(hash, id, src, dst);
 349 }
 350
 351
 352 static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 353                            struct frag_hdr *fhdr, int nhoff)
 354 {
 355         struct sk_buff *prev, *next;
 356         int offset, end;
 357
 358         if (fq->last_in & COMPLETE)
 359                 goto err;
 360
 361         offset = ntohs(fhdr->frag_off) & ~0x7;
 362         end = offset + (ntohs(skb->nh.ipv6h->payload_len) -
 363                         ((u8 *) (fhdr + 1) - (u8 *) (skb->nh.ipv6h + 1)));
 364
 365         if ((unsigned int)end >= 65536) {
 366                 icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw);
 367                 return;
 368         }
 369
 370         if (skb->ip_summed == CHECKSUM_HW)
 371                 skb->csum = csum_sub(skb->csum,
 372                                      csum_partial(skb->nh.raw, (u8*)(fhdr+1)-skb->nh.raw, 0));
 373
 374         /* Is this the final fragment? */
 375         if (!(fhdr->frag_off & htons(0x0001))) {
 376                 /* If we already have some bits beyond end
 377                  * or have different end, the segment is corrupted.
 378                  */
 379                 if (end < fq->len ||
 380                     ((fq->last_in & LAST_IN) && end != fq->len))
 381                         goto err;
 382                 fq->last_in |= LAST_IN;
 383                 fq->len = end;
 384         } else {
 385                 /* Check if the fragment is rounded to 8 bytes.
 386                  * Required by the RFC.
 387                  */
 388                 if (end & 0x7) {
 389                         /* RFC2460 says always send parameter problem in
 390                          * this case. -DaveM
 391                          */
 392                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 393                                           offsetof(struct ipv6hdr, payload_len));
 394                         return;
 395                 }
 396                 if (end > fq->len) {
 397                         /* Some bits beyond end -> corruption. */
 398                         if (fq->last_in & LAST_IN)
 399                                 goto err;
 400                         fq->len = end;
 401                 }
 402         }
 403
 404         if (end == offset)
 405                 goto err;
 406
 407         /* Point into the IP datagram 'data' part. */
 408         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 409                 goto err;
 410         if (end-offset < skb->len) {
 411                 if (pskb_trim(skb, end - offset))
 412                         goto err;
 413                 if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 414                         skb->ip_summed = CHECKSUM_NONE;
 415         }
 416
 417         /* Find out which fragments are in front and at the back of us
 418          * in the chain of fragments so far.  We must know where to put
 419          * this fragment, right?
 420          */
 421         prev = NULL;
 422         for(next = fq->fragments; next != NULL; next = next->next) {
 423                 if (FRAG6_CB(next)->offset >= offset)
 424                         break;  /* bingo! */
 425                 prev = next;
 426         }
 427
 428         /* We found where to put this one.  Check for overlap with
 429          * preceding fragment, and, if needed, align things so that
 430          * any overlaps are eliminated.
 431          */
 432         if (prev) {
 433                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
 434
 435                 if (i > 0) {
 436                         offset += i;
 437                         if (end <= offset)
 438                                 goto err;
 439                         if (!pskb_pull(skb, i))
 440                                 goto err;
 441                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 442                                 skb->ip_summed = CHECKSUM_NONE;
 443                 }
 444         }
 445
 446         /* Look for overlap with succeeding segments.
 447          * If we can merge fragments, do it.
 448          */
 449         while (next && FRAG6_CB(next)->offset < end) {
 450                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
 451
 452                 if (i < next->len) {
 453                         /* Eat head of the next overlapped fragment
 454                          * and leave the loop. The next ones cannot overlap.
 455                          */
 456                         if (!pskb_pull(next, i))
 457                                 goto err;
 458                         FRAG6_CB(next)->offset += i;    /* next fragment */
 459                         fq->meat -= i;
 460                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 461                                 next->ip_summed = CHECKSUM_NONE;
 462                         break;
 463                 } else {
 464                         struct sk_buff *free_it = next;
 465
 466                         /* Old fragmnet is completely overridden with
 467                          * new one drop it.
 468                          */
 469                         next = next->next;
 470
 471                         if (prev)
 472                                 prev->next = next;
 473                         else
 474                                 fq->fragments = next;
 475
 476                         fq->meat -= free_it->len;
 477                         frag_kfree_skb(free_it);
 478                 }
 479         }
 480
 481         FRAG6_CB(skb)->offset = offset;
 482
 483         /* Insert this fragment in the chain of fragments. */
 484         skb->next = next;
 485         if (prev)
 486                 prev->next = skb;
 487         else
 488                 fq->fragments = skb;
 489
 490         if (skb->dev)
 491                 fq->iif = skb->dev->ifindex;
 492         skb->dev = NULL;
 493         fq->stamp = skb->stamp;
 494         fq->meat += skb->len;
 495         atomic_add(skb->truesize, &ip6_frag_mem);
 496
 497         /* The first fragment.
 498          * nhoffset is obtained from the first fragment, of course.
 499          */
 500         if (offset == 0) {
 501                 fq->nhoffset = nhoff;
 502                 fq->last_in |= FIRST_IN;
 503         }
 504         return;
 505
 506 err:
 507         kfree_skb(skb);
 508 }
 509
 510 /*
 511  *      Check if this packet is complete.
 512  *      Returns NULL on failure by any reason, and pointer
 513  *      to current nexthdr field in reassembled frame.
 514  *
 515  *      It is called with locked fq, and caller must check that
 516  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 517  *      the last and the first frames arrived and all the bits are here.
 518  */
 519 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in,
 520                           struct net_device *dev)
 521 {
 522         struct sk_buff *fp, *head = fq->fragments;
 523         int    remove_fraghdr = 0;
 524         int    payload_len;
 525         int    nhoff;
 526
 527         fq_kill(fq);
 528
 529         BUG_TRAP(head != NULL);
 530         BUG_TRAP(FRAG6_CB(head)->offset == 0);
 531
 532         /* Unfragmented part is taken from the first segment. */
 533         payload_len = (head->data - head->nh.raw) - sizeof(struct ipv6hdr) + fq->len;
 534         nhoff = head->h.raw - head->nh.raw;
 535
 536         if (payload_len > 65535) {
 537                 payload_len -= 8;
 538                 if (payload_len > 65535)
 539                         goto out_oversize;
 540                 remove_fraghdr = 1;
 541         }
 542
 543         /* Head of list must not be cloned. */
 544         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 545                 goto out_oom;
 546
 547         /* If the first fragment is fragmented itself, we split
 548          * it to two chunks: the first with data and paged part
 549          * and the second, holding only fragments. */
 550         if (skb_shinfo(head)->frag_list) {
 551                 struct sk_buff *clone;
 552                 int i, plen = 0;
 553
 554                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 555                         goto out_oom;
 556                 clone->next = head->next;
 557                 head->next = clone;
 558                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 559                 skb_shinfo(head)->frag_list = NULL;
 560                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 561                         plen += skb_shinfo(head)->frags[i].size;
 562                 clone->len = clone->data_len = head->data_len - plen;
 563                 head->data_len -= clone->len;
 564                 head->len -= clone->len;
 565                 clone->csum = 0;
 566                 clone->ip_summed = head->ip_summed;
 567                 atomic_add(clone->truesize, &ip6_frag_mem);
 568         }
 569
 570         /* Normally we do not remove frag header from datagram, but
 571          * we have to do this and to relocate header, when payload
 572          * is > 65535-8. */
 573         if (remove_fraghdr) {
 574                 nhoff = fq->nhoffset;
 575                 head->nh.raw[nhoff] = head->h.raw[0];
 576                 memmove(head->head+8, head->head, (head->data-head->head)-8);
 577                 head->mac.raw += 8;
 578                 head->nh.raw += 8;
 579         } else {
 580                 ((struct frag_hdr*)head->h.raw)->frag_off = 0;
 581         }
 582
 583         skb_shinfo(head)->frag_list = head->next;
 584         head->h.raw = head->data;
 585         skb_push(head, head->data - head->nh.raw);
 586         atomic_sub(head->truesize, &ip6_frag_mem);
 587
 588         for (fp=head->next; fp; fp = fp->next) {
 589                 head->data_len += fp->len;
 590                 head->len += fp->len;
 591                 if (head->ip_summed != fp->ip_summed)
 592                         head->ip_summed = CHECKSUM_NONE;
 593                 else if (head->ip_summed == CHECKSUM_HW)
 594                         head->csum = csum_add(head->csum, fp->csum);
 595                 head->truesize += fp->truesize;
 596                 atomic_sub(fp->truesize, &ip6_frag_mem);
 597         }
 598
 599         head->next = NULL;
 600         head->dev = dev;
 601         head->stamp = fq->stamp;
 602         head->nh.ipv6h->payload_len = ntohs(payload_len);
 603
 604         *skb_in = head;
 605
 606         /* Yes, and fold redundant checksum back. 8) */
 607         if (head->ip_summed == CHECKSUM_HW)
 608                 head->csum = csum_partial(head->nh.raw, head->h.raw-head->nh.raw, head->csum);
 609
 610         IP6_INC_STATS_BH(Ip6ReasmOKs);
 611         fq->fragments = NULL;
 612         return nhoff;
 613
 614 out_oversize:
 615         if (net_ratelimit())
 616                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
 617         goto out_fail;
 618 out_oom:
 619         if (net_ratelimit())
 620                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
 621 out_fail:
 622         IP6_INC_STATS_BH(Ip6ReasmFails);
 623         return -1;
 624 }
 625
 626 int ipv6_reassembly(struct sk_buff **skbp, int nhoff)
 627 {
 628         struct sk_buff *skb = *skbp;
 629         struct net_device *dev = skb->dev;
 630         struct frag_hdr *fhdr;
 631         struct frag_queue *fq;
 632         struct ipv6hdr *hdr;
 633
 634         hdr = skb->nh.ipv6h;
 635
 636         IP6_INC_STATS_BH(Ip6ReasmReqds);
 637
 638         /* Jumbo payload inhibits frag. header */
 639         if (hdr->payload_len==0) {
 640                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
 641                 return -1;
 642         }
 643         if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) {
 644                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
 645                 return -1;
 646         }
 647
 648         hdr = skb->nh.ipv6h;
 649         fhdr = (struct frag_hdr *)skb->h.raw;
 650
 651         if (!(fhdr->frag_off & htons(0xFFF9))) {
 652                 /* It is not a fragmented frame */
 653                 skb->h.raw += sizeof(struct frag_hdr);
 654                 IP6_INC_STATS_BH(Ip6ReasmOKs);
 655
 656                 return (u8*)fhdr - skb->nh.raw;
 657         }
 658
 659         if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh)
 660                 ip6_evictor();
 661
 662         if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr)) != NULL) {
 663                 int ret = -1;
 664
 665                 spin_lock(&fq->lock);
 666
 667                 ip6_frag_queue(fq, skb, fhdr, nhoff);
 668
 669                 if (fq->last_in == (FIRST_IN|LAST_IN) &&
 670                     fq->meat == fq->len)
 671                         ret = ip6_frag_reasm(fq, skbp, dev);
 672
 673                 spin_unlock(&fq->lock);
 674                 fq_put(fq);
 675                 return ret;
 676         }
 677
 678         IP6_INC_STATS_BH(Ip6ReasmFails);
 679         kfree_skb(skb);
 680         return -1;
 681 }