net/ipv6/reassembly.c

   1 /*
   2  *      IPv6 fragment reassembly
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <pedro_m@yahoo.com>
   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  */
  27 #include <linux/config.h>
  28 #include <linux/errno.h>
  29 #include <linux/types.h>
  30 #include <linux/string.h>
  31 #include <linux/socket.h>
  32 #include <linux/sockios.h>
  33 #include <linux/sched.h>
  34 #include <linux/list.h>
  35 #include <linux/net.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/in6.h>
  38 #include <linux/ipv6.h>
  39 #include <linux/icmpv6.h>
  40 #include <linux/random.h>
  41 #include <linux/jhash.h>
  42
  43 #include <net/sock.h>
  44 #include <net/snmp.h>
  45
  46 #include <net/ipv6.h>
  47 #include <net/protocol.h>
  48 #include <net/transp_v6.h>
  49 #include <net/rawv6.h>
  50 #include <net/ndisc.h>
  51 #include <net/addrconf.h>
  52
  53 int sysctl_ip6frag_high_thresh = 256*1024;
  54 int sysctl_ip6frag_low_thresh = 192*1024;
  55
  56 int sysctl_ip6frag_time = IPV6_FRAG_TIMEOUT;
  57
  58 struct ip6frag_skb_cb
  59 {
  60         struct inet6_skb_parm   h;
  61         int                     offset;
  62 };
  63
  64 #define FRAG6_CB(skb)   ((struct ip6frag_skb_cb*)((skb)->cb))
  65
  66
  67 /*
  68  *      Equivalent of ipv4 struct ipq
  69  */
  70
  71 struct frag_queue
  72 {
  73         struct frag_queue       *next;
  74         struct list_head lru_list;              /* lru list member      */
  75
  76         __u32                   id;             /* fragment id          */
  77         struct in6_addr         saddr;
  78         struct in6_addr         daddr;
  79
  80         spinlock_t              lock;
  81         atomic_t                refcnt;
  82         struct timer_list       timer;          /* expire timer         */
  83         struct sk_buff          *fragments;
  84         int                     len;
  85         int                     meat;
  86         int                     iif;
  87         struct timeval          stamp;
  88         unsigned int            csum;
  89         __u8                    last_in;        /* has first/last segment arrived? */
  90 #define COMPLETE                4
  91 #define FIRST_IN                2
  92 #define LAST_IN                 1
  93         __u16                   nhoffset;
  94         struct frag_queue       **pprev;
  95 };
  96
  97 /* Hash table. */
  98
  99 #define IP6Q_HASHSZ     64
 100
 101 static struct frag_queue *ip6_frag_hash[IP6Q_HASHSZ];
 102 static rwlock_t ip6_frag_lock = RW_LOCK_UNLOCKED;
 103 static u32 ip6_frag_hash_rnd;
 104 static LIST_HEAD(ip6_frag_lru_list);
 105 int ip6_frag_nqueues = 0;
 106
 107 static __inline__ void __fq_unlink(struct frag_queue *fq)
 108 {
 109         if(fq->next)
 110                 fq->next->pprev = fq->pprev;
 111         *fq->pprev = fq->next;
 112         list_del(&fq->lru_list);
 113         ip6_frag_nqueues--;
 114 }
 115
 116 static __inline__ void fq_unlink(struct frag_queue *fq)
 117 {
 118         write_lock(&ip6_frag_lock);
 119         __fq_unlink(fq);
 120         write_unlock(&ip6_frag_lock);
 121 }
 122
 123 static unsigned int ip6qhashfn(u32 id, struct in6_addr *saddr,
 124                                struct in6_addr *daddr)
 125 {
 126         u32 a, b, c;
 127
 128         a = saddr->s6_addr32[0];
 129         b = saddr->s6_addr32[1];
 130         c = saddr->s6_addr32[2];
 131
 132         a += JHASH_GOLDEN_RATIO;
 133         b += JHASH_GOLDEN_RATIO;
 134         c += ip6_frag_hash_rnd;
 135         __jhash_mix(a, b, c);
 136
 137         a += saddr->s6_addr32[3];
 138         b += daddr->s6_addr32[0];
 139         c += daddr->s6_addr32[1];
 140         __jhash_mix(a, b, c);
 141
 142         a += daddr->s6_addr32[2];
 143         b += daddr->s6_addr32[3];
 144         c += id;
 145         __jhash_mix(a, b, c);
 146
 147         return c & (IP6Q_HASHSZ - 1);
 148 }
 149
 150 static struct timer_list ip6_frag_secret_timer;
 151 static int ip6_frag_secret_interval = 10 * 60 * HZ;
 152
 153 static void ip6_frag_secret_rebuild(unsigned long dummy)
 154 {
 155         unsigned long now = jiffies;
 156         int i;
 157
 158         write_lock(&ip6_frag_lock);
 159         get_random_bytes(&ip6_frag_hash_rnd, sizeof(u32));
 160         for (i = 0; i < IP6Q_HASHSZ; i++) {
 161                 struct frag_queue *q;
 162
 163                 q = ip6_frag_hash[i];
 164                 while (q) {
 165                         struct frag_queue *next = q->next;
 166                         unsigned int hval = ip6qhashfn(q->id,
 167                                                        &q->saddr,
 168                                                        &q->daddr);
 169
 170                         if (hval != i) {
 171                                 /* Unlink. */
 172                                 if (q->next)
 173                                         q->next->pprev = q->pprev;
 174                                 *q->pprev = q->next;
 175
 176                                 /* Relink to new hash chain. */
 177                                 if ((q->next = ip6_frag_hash[hval]) != NULL)
 178                                         q->next->pprev = &q->next;
 179                                 ip6_frag_hash[hval] = q;
 180                                 q->pprev = &ip6_frag_hash[hval];
 181                         }
 182
 183                         q = next;
 184                 }
 185         }
 186         write_unlock(&ip6_frag_lock);
 187
 188         mod_timer(&ip6_frag_secret_timer, now + ip6_frag_secret_interval);
 189 }
 190
 191 atomic_t ip6_frag_mem = ATOMIC_INIT(0);
 192
 193 /* Memory Tracking Functions. */
 194 static inline void frag_kfree_skb(struct sk_buff *skb, int *work)
 195 {
 196         if (work)
 197                 *work -= skb->truesize;
 198         atomic_sub(skb->truesize, &ip6_frag_mem);
 199         kfree_skb(skb);
 200 }
 201
 202 static inline void frag_free_queue(struct frag_queue *fq, int *work)
 203 {
 204         if (work)
 205                 *work -= sizeof(struct frag_queue);
 206         atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem);
 207         kfree(fq);
 208 }
 209
 210 static inline struct frag_queue *frag_alloc_queue(void)
 211 {
 212         struct frag_queue *fq = kmalloc(sizeof(struct frag_queue), GFP_ATOMIC);
 213
 214         if(!fq)
 215                 return NULL;
 216         atomic_add(sizeof(struct frag_queue), &ip6_frag_mem);
 217         return fq;
 218 }
 219
 220 /* Destruction primitives. */
 221
 222 /* Complete destruction of fq. */
 223 static void ip6_frag_destroy(struct frag_queue *fq, int *work)
 224 {
 225         struct sk_buff *fp;
 226
 227         BUG_TRAP(fq->last_in&COMPLETE);
 228         BUG_TRAP(del_timer(&fq->timer) == 0);
 229
 230         /* Release all fragment data. */
 231         fp = fq->fragments;
 232         while (fp) {
 233                 struct sk_buff *xp = fp->next;
 234
 235                 frag_kfree_skb(fp, work);
 236                 fp = xp;
 237         }
 238
 239         frag_free_queue(fq, work);
 240 }
 241
 242 static __inline__ void fq_put(struct frag_queue *fq, int *work)
 243 {
 244         if (atomic_dec_and_test(&fq->refcnt))
 245                 ip6_frag_destroy(fq, work);
 246 }
 247
 248 /* Kill fq entry. It is not destroyed immediately,
 249  * because caller (and someone more) holds reference count.
 250  */
 251 static __inline__ void fq_kill(struct frag_queue *fq)
 252 {
 253         if (del_timer(&fq->timer))
 254                 atomic_dec(&fq->refcnt);
 255
 256         if (!(fq->last_in & COMPLETE)) {
 257                 fq_unlink(fq);
 258                 atomic_dec(&fq->refcnt);
 259                 fq->last_in |= COMPLETE;
 260         }
 261 }
 262
 263 static void ip6_evictor(void)
 264 {
 265         struct frag_queue *fq;
 266         struct list_head *tmp;
 267         int work;
 268
 269         work = atomic_read(&ip6_frag_mem) - sysctl_ip6frag_low_thresh;
 270         if (work <= 0)
 271                 return;
 272
 273         while(work > 0) {
 274                 read_lock(&ip6_frag_lock);
 275                 if (list_empty(&ip6_frag_lru_list)) {
 276                         read_unlock(&ip6_frag_lock);
 277                         return;
 278                 }
 279                 tmp = ip6_frag_lru_list.next;
 280                 fq = list_entry(tmp, struct frag_queue, lru_list);
 281                 atomic_inc(&fq->refcnt);
 282                 read_unlock(&ip6_frag_lock);
 283
 284                 spin_lock(&fq->lock);
 285                 if (!(fq->last_in&COMPLETE))
 286                         fq_kill(fq);
 287                 spin_unlock(&fq->lock);
 288
 289                 fq_put(fq, &work);
 290                 IP6_INC_STATS_BH(Ip6ReasmFails);
 291         }
 292 }
 293
 294 static void ip6_frag_expire(unsigned long data)
 295 {
 296         struct frag_queue *fq = (struct frag_queue *) data;
 297
 298         spin_lock(&fq->lock);
 299
 300         if (fq->last_in & COMPLETE)
 301                 goto out;
 302
 303         fq_kill(fq);
 304
 305         IP6_INC_STATS_BH(Ip6ReasmTimeout);
 306         IP6_INC_STATS_BH(Ip6ReasmFails);
 307
 308         /* Send error only if the first segment arrived. */
 309         if (fq->last_in&FIRST_IN && fq->fragments) {
 310                 struct net_device *dev = dev_get_by_index(fq->iif);
 311
 312                 /*
 313                    But use as source device on which LAST ARRIVED
 314                    segment was received. And do not use fq->dev
 315                    pointer directly, device might already disappeared.
 316                  */
 317                 if (dev) {
 318                         fq->fragments->dev = dev;
 319                         icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0,
 320                                     dev);
 321                         dev_put(dev);
 322                 }
 323         }
 324 out:
 325         spin_unlock(&fq->lock);
 326         fq_put(fq, NULL);
 327 }
 328
 329 /* Creation primitives. */
 330
 331
 332 static struct frag_queue *ip6_frag_intern(unsigned int hash,
 333                                           struct frag_queue *fq_in)
 334 {
 335         struct frag_queue *fq;
 336
 337         write_lock(&ip6_frag_lock);
 338 #ifdef CONFIG_SMP
 339         for (fq = ip6_frag_hash[hash]; fq; fq = fq->next) {
 340                 if (fq->id == fq_in->id &&
 341                     !ipv6_addr_cmp(&fq_in->saddr, &fq->saddr) &&
 342                     !ipv6_addr_cmp(&fq_in->daddr, &fq->daddr)) {
 343                         atomic_inc(&fq->refcnt);
 344                         write_unlock(&ip6_frag_lock);
 345                         fq_in->last_in |= COMPLETE;
 346                         fq_put(fq_in, NULL);
 347                         return fq;
 348                 }
 349         }
 350 #endif
 351         fq = fq_in;
 352
 353         if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time))
 354                 atomic_inc(&fq->refcnt);
 355
 356         atomic_inc(&fq->refcnt);
 357         if((fq->next = ip6_frag_hash[hash]) != NULL)
 358                 fq->next->pprev = &fq->next;
 359         ip6_frag_hash[hash] = fq;
 360         fq->pprev = &ip6_frag_hash[hash];
 361         INIT_LIST_HEAD(&fq->lru_list);
 362         list_add_tail(&fq->lru_list, &ip6_frag_lru_list);
 363         ip6_frag_nqueues++;
 364         write_unlock(&ip6_frag_lock);
 365         return fq;
 366 }
 367
 368
 369 static struct frag_queue *
 370 ip6_frag_create(unsigned int hash, u32 id, struct in6_addr *src, struct in6_addr *dst)
 371 {
 372         struct frag_queue *fq;
 373
 374         if ((fq = frag_alloc_queue()) == NULL)
 375                 goto oom;
 376
 377         memset(fq, 0, sizeof(struct frag_queue));
 378
 379         fq->id = id;
 380         ipv6_addr_copy(&fq->saddr, src);
 381         ipv6_addr_copy(&fq->daddr, dst);
 382
 383         /* init_timer has been done by the memset */
 384         fq->timer.function = ip6_frag_expire;
 385         fq->timer.data = (long) fq;
 386         fq->lock = SPIN_LOCK_UNLOCKED;
 387         atomic_set(&fq->refcnt, 1);
 388
 389         return ip6_frag_intern(hash, fq);
 390
 391 oom:
 392         IP6_INC_STATS_BH(Ip6ReasmFails);
 393         return NULL;
 394 }
 395
 396 static __inline__ struct frag_queue *
 397 fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst)
 398 {
 399         struct frag_queue *fq;
 400         unsigned int hash = ip6qhashfn(id, src, dst);
 401
 402         read_lock(&ip6_frag_lock);
 403         for(fq = ip6_frag_hash[hash]; fq; fq = fq->next) {
 404                 if (fq->id == id &&
 405                     !ipv6_addr_cmp(src, &fq->saddr) &&
 406                     !ipv6_addr_cmp(dst, &fq->daddr)) {
 407                         atomic_inc(&fq->refcnt);
 408                         read_unlock(&ip6_frag_lock);
 409                         return fq;
 410                 }
 411         }
 412         read_unlock(&ip6_frag_lock);
 413
 414         return ip6_frag_create(hash, id, src, dst);
 415 }
 416
 417
 418 static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 419                            struct frag_hdr *fhdr, int nhoff)
 420 {
 421         struct sk_buff *prev, *next;
 422         int offset, end;
 423
 424         if (fq->last_in & COMPLETE)
 425                 goto err;
 426
 427         offset = ntohs(fhdr->frag_off) & ~0x7;
 428         end = offset + (ntohs(skb->nh.ipv6h->payload_len) -
 429                         ((u8 *) (fhdr + 1) - (u8 *) (skb->nh.ipv6h + 1)));
 430
 431         if ((unsigned int)end >= 65536) {
 432                 icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw);
 433                 return;
 434         }
 435
 436         if (skb->ip_summed == CHECKSUM_HW)
 437                 skb->csum = csum_sub(skb->csum,
 438                                      csum_partial(skb->nh.raw, (u8*)(fhdr+1)-skb->nh.raw, 0));
 439
 440         /* Is this the final fragment? */
 441         if (!(fhdr->frag_off & htons(0x0001))) {
 442                 /* If we already have some bits beyond end
 443                  * or have different end, the segment is corrupted.
 444                  */
 445                 if (end < fq->len ||
 446                     ((fq->last_in & LAST_IN) && end != fq->len))
 447                         goto err;
 448                 fq->last_in |= LAST_IN;
 449                 fq->len = end;
 450         } else {
 451                 /* Check if the fragment is rounded to 8 bytes.
 452                  * Required by the RFC.
 453                  */
 454                 if (end & 0x7) {
 455                         /* RFC2460 says always send parameter problem in
 456                          * this case. -DaveM
 457                          */
 458                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 459                                           offsetof(struct ipv6hdr, payload_len));
 460                         return;
 461                 }
 462                 if (end > fq->len) {
 463                         /* Some bits beyond end -> corruption. */
 464                         if (fq->last_in & LAST_IN)
 465                                 goto err;
 466                         fq->len = end;
 467                 }
 468         }
 469
 470         if (end == offset)
 471                 goto err;
 472
 473         /* Point into the IP datagram 'data' part. */
 474         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 475                 goto err;
 476         if (end-offset < skb->len) {
 477                 if (pskb_trim(skb, end - offset))
 478                         goto err;
 479                 if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 480                         skb->ip_summed = CHECKSUM_NONE;
 481         }
 482
 483         /* Find out which fragments are in front and at the back of us
 484          * in the chain of fragments so far.  We must know where to put
 485          * this fragment, right?
 486          */
 487         prev = NULL;
 488         for(next = fq->fragments; next != NULL; next = next->next) {
 489                 if (FRAG6_CB(next)->offset >= offset)
 490                         break;  /* bingo! */
 491                 prev = next;
 492         }
 493
 494         /* We found where to put this one.  Check for overlap with
 495          * preceding fragment, and, if needed, align things so that
 496          * any overlaps are eliminated.
 497          */
 498         if (prev) {
 499                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
 500
 501                 if (i > 0) {
 502                         offset += i;
 503                         if (end <= offset)
 504                                 goto err;
 505                         if (!pskb_pull(skb, i))
 506                                 goto err;
 507                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 508                                 skb->ip_summed = CHECKSUM_NONE;
 509                 }
 510         }
 511
 512         /* Look for overlap with succeeding segments.
 513          * If we can merge fragments, do it.
 514          */
 515         while (next && FRAG6_CB(next)->offset < end) {
 516                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
 517
 518                 if (i < next->len) {
 519                         /* Eat head of the next overlapped fragment
 520                          * and leave the loop. The next ones cannot overlap.
 521                          */
 522                         if (!pskb_pull(next, i))
 523                                 goto err;
 524                         FRAG6_CB(next)->offset += i;    /* next fragment */
 525                         fq->meat -= i;
 526                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 527                                 next->ip_summed = CHECKSUM_NONE;
 528                         break;
 529                 } else {
 530                         struct sk_buff *free_it = next;
 531
 532                         /* Old fragmnet is completely overridden with
 533                          * new one drop it.
 534                          */
 535                         next = next->next;
 536
 537                         if (prev)
 538                                 prev->next = next;
 539                         else
 540                                 fq->fragments = next;
 541
 542                         fq->meat -= free_it->len;
 543                         frag_kfree_skb(free_it, NULL);
 544                 }
 545         }
 546
 547         FRAG6_CB(skb)->offset = offset;
 548
 549         /* Insert this fragment in the chain of fragments. */
 550         skb->next = next;
 551         if (prev)
 552                 prev->next = skb;
 553         else
 554                 fq->fragments = skb;
 555
 556         if (skb->dev)
 557                 fq->iif = skb->dev->ifindex;
 558         skb->dev = NULL;
 559         fq->stamp = skb->stamp;
 560         fq->meat += skb->len;
 561         atomic_add(skb->truesize, &ip6_frag_mem);
 562
 563         /* The first fragment.
 564          * nhoffset is obtained from the first fragment, of course.
 565          */
 566         if (offset == 0) {
 567                 fq->nhoffset = nhoff;
 568                 fq->last_in |= FIRST_IN;
 569         }
 570         write_lock(&ip6_frag_lock);
 571         list_move_tail(&fq->lru_list, &ip6_frag_lru_list);
 572         write_unlock(&ip6_frag_lock);
 573         return;
 574
 575 err:
 576         kfree_skb(skb);
 577 }
 578
 579 /*
 580  *      Check if this packet is complete.
 581  *      Returns NULL on failure by any reason, and pointer
 582  *      to current nexthdr field in reassembled frame.
 583  *
 584  *      It is called with locked fq, and caller must check that
 585  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 586  *      the last and the first frames arrived and all the bits are here.
 587  */
 588 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in,
 589                           struct net_device *dev)
 590 {
 591         struct sk_buff *fp, *head = fq->fragments;
 592         int    remove_fraghdr = 0;
 593         int    payload_len;
 594         int    nhoff;
 595
 596         fq_kill(fq);
 597
 598         BUG_TRAP(head != NULL);
 599         BUG_TRAP(FRAG6_CB(head)->offset == 0);
 600
 601         /* Unfragmented part is taken from the first segment. */
 602         payload_len = (head->data - head->nh.raw) - sizeof(struct ipv6hdr) + fq->len;
 603         nhoff = head->h.raw - head->nh.raw;
 604
 605         if (payload_len > 65535) {
 606                 payload_len -= 8;
 607                 if (payload_len > 65535)
 608                         goto out_oversize;
 609                 remove_fraghdr = 1;
 610         }
 611
 612         /* Head of list must not be cloned. */
 613         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 614                 goto out_oom;
 615
 616         /* If the first fragment is fragmented itself, we split
 617          * it to two chunks: the first with data and paged part
 618          * and the second, holding only fragments. */
 619         if (skb_shinfo(head)->frag_list) {
 620                 struct sk_buff *clone;
 621                 int i, plen = 0;
 622
 623                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 624                         goto out_oom;
 625                 clone->next = head->next;
 626                 head->next = clone;
 627                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 628                 skb_shinfo(head)->frag_list = NULL;
 629                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 630                         plen += skb_shinfo(head)->frags[i].size;
 631                 clone->len = clone->data_len = head->data_len - plen;
 632                 head->data_len -= clone->len;
 633                 head->len -= clone->len;
 634                 clone->csum = 0;
 635                 clone->ip_summed = head->ip_summed;
 636                 atomic_add(clone->truesize, &ip6_frag_mem);
 637         }
 638
 639         /* Normally we do not remove frag header from datagram, but
 640          * we have to do this and to relocate header, when payload
 641          * is > 65535-8. */
 642         if (remove_fraghdr) {
 643                 nhoff = fq->nhoffset;
 644                 head->nh.raw[nhoff] = head->h.raw[0];
 645                 memmove(head->head+8, head->head, (head->data-head->head)-8);
 646                 head->mac.raw += 8;
 647                 head->nh.raw += 8;
 648         } else {
 649                 ((struct frag_hdr*)head->h.raw)->frag_off = 0;
 650         }
 651
 652         skb_shinfo(head)->frag_list = head->next;
 653         head->h.raw = head->data;
 654         skb_push(head, head->data - head->nh.raw);
 655         atomic_sub(head->truesize, &ip6_frag_mem);
 656
 657         for (fp=head->next; fp; fp = fp->next) {
 658                 head->data_len += fp->len;
 659                 head->len += fp->len;
 660                 if (head->ip_summed != fp->ip_summed)
 661                         head->ip_summed = CHECKSUM_NONE;
 662                 else if (head->ip_summed == CHECKSUM_HW)
 663                         head->csum = csum_add(head->csum, fp->csum);
 664                 head->truesize += fp->truesize;
 665                 atomic_sub(fp->truesize, &ip6_frag_mem);
 666         }
 667
 668         head->next = NULL;
 669         head->dev = dev;
 670         head->stamp = fq->stamp;
 671         head->nh.ipv6h->payload_len = ntohs(payload_len);
 672
 673         *skb_in = head;
 674
 675         /* Yes, and fold redundant checksum back. 8) */
 676         if (head->ip_summed == CHECKSUM_HW)
 677                 head->csum = csum_partial(head->nh.raw, head->h.raw-head->nh.raw, head->csum);
 678
 679         IP6_INC_STATS_BH(Ip6ReasmOKs);
 680         fq->fragments = NULL;
 681         return nhoff;
 682
 683 out_oversize:
 684         if (net_ratelimit())
 685                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
 686         goto out_fail;
 687 out_oom:
 688         if (net_ratelimit())
 689                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
 690 out_fail:
 691         IP6_INC_STATS_BH(Ip6ReasmFails);
 692         return -1;
 693 }
 694
 695 int ipv6_reassembly(struct sk_buff **skbp, int nhoff)
 696 {
 697         struct sk_buff *skb = *skbp;
 698         struct net_device *dev = skb->dev;
 699         struct frag_hdr *fhdr;
 700         struct frag_queue *fq;
 701         struct ipv6hdr *hdr;
 702
 703         hdr = skb->nh.ipv6h;
 704
 705         IP6_INC_STATS_BH(Ip6ReasmReqds);
 706
 707         /* Jumbo payload inhibits frag. header */
 708         if (hdr->payload_len==0) {
 709                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
 710                 return -1;
 711         }
 712         if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) {
 713                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
 714                 return -1;
 715         }
 716
 717         hdr = skb->nh.ipv6h;
 718         fhdr = (struct frag_hdr *)skb->h.raw;
 719
 720         if (!(fhdr->frag_off & htons(0xFFF9))) {
 721                 /* It is not a fragmented frame */
 722                 skb->h.raw += sizeof(struct frag_hdr);
 723                 IP6_INC_STATS_BH(Ip6ReasmOKs);
 724
 725                 return (u8*)fhdr - skb->nh.raw;
 726         }
 727
 728         if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh)
 729                 ip6_evictor();
 730
 731         if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr)) != NULL) {
 732                 int ret = -1;
 733
 734                 spin_lock(&fq->lock);
 735
 736                 ip6_frag_queue(fq, skb, fhdr, nhoff);
 737
 738                 if (fq->last_in == (FIRST_IN|LAST_IN) &&
 739                     fq->meat == fq->len)
 740                         ret = ip6_frag_reasm(fq, skbp, dev);
 741
 742                 spin_unlock(&fq->lock);
 743                 fq_put(fq, NULL);
 744                 return ret;
 745         }
 746
 747         IP6_INC_STATS_BH(Ip6ReasmFails);
 748         kfree_skb(skb);
 749         return -1;
 750 }
 751
 752 void __init ipv6_frag_init(void)
 753 {
 754         ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
 755                                    (jiffies ^ (jiffies >> 6)));
 756
 757         init_timer(&ip6_frag_secret_timer);
 758         ip6_frag_secret_timer.function = ip6_frag_secret_rebuild;
 759         ip6_frag_secret_timer.expires = jiffies + ip6_frag_secret_interval;
 760         add_timer(&ip6_frag_secret_timer);
 761 }