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  *      Based on: net/ipv4/ip_fragment.c
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  */
  15
  16 /*
  17  *      Fixes:
  18  *      Andi Kleen      Make it work with multiple hosts.
  19  *                      More RFC compliance.
  20  *
  21  *      Horst von Brand Add missing #include <linux/string.h>
  22  *      Alexey Kuznetsov        SMP races, threading, cleanup.
  23  *      Patrick McHardy         LRU queue of frag heads for evictor.
  24  *      Mitsuru KANDA @USAGI    Register inet6_protocol{}.
  25  *      David Stevens and
  26  *      YOSHIFUJI,H. @USAGI     Always remove fragment header to
  27  *                              calculate ICV correctly.
  28  */
  29 #include <linux/errno.h>
  30 #include <linux/types.h>
  31 #include <linux/string.h>
  32 #include <linux/socket.h>
  33 #include <linux/sockios.h>
  34 #include <linux/jiffies.h>
  35 #include <linux/net.h>
  36 #include <linux/list.h>
  37 #include <linux/netdevice.h>
  38 #include <linux/in6.h>
  39 #include <linux/ipv6.h>
  40 #include <linux/icmpv6.h>
  41 #include <linux/random.h>
  42 #include <linux/jhash.h>
  43 #include <linux/skbuff.h>
  44
  45 #include <net/sock.h>
  46 #include <net/snmp.h>
  47
  48 #include <net/ipv6.h>
  49 #include <net/ip6_route.h>
  50 #include <net/protocol.h>
  51 #include <net/transp_v6.h>
  52 #include <net/rawv6.h>
  53 #include <net/ndisc.h>
  54 #include <net/addrconf.h>
  55 #include <net/inet_frag.h>
  56
  57 struct ip6frag_skb_cb
  58 {
  59         struct inet6_skb_parm   h;
  60         int                     offset;
  61 };
  62
  63 #define FRAG6_CB(skb)   ((struct ip6frag_skb_cb*)((skb)->cb))
  64
  65
  66 /*
  67  *      Equivalent of ipv4 struct ipq
  68  */
  69
  70 struct frag_queue
  71 {
  72         struct inet_frag_queue  q;
  73
  74         __be32                  id;             /* fragment id          */
  75         struct in6_addr         saddr;
  76         struct in6_addr         daddr;
  77
  78         int                     iif;
  79         unsigned int            csum;
  80         __u16                   nhoffset;
  81 };
  82
  83 static struct inet_frags ip6_frags;
  84
  85 int ip6_frag_nqueues(struct net *net)
  86 {
  87         return net->ipv6.frags.nqueues;
  88 }
  89
  90 int ip6_frag_mem(struct net *net)
  91 {
  92         return atomic_read(&net->ipv6.frags.mem);
  93 }
  94
  95 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
  96                           struct net_device *dev);
  97
  98 /*
  99  * callers should be careful not to use the hash value outside the ipfrag_lock
 100  * as doing so could race with ipfrag_hash_rnd being recalculated.
 101  */
 102 unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
 103                              const struct in6_addr *daddr, u32 rnd)
 104 {
 105         u32 a, b, c;
 106
 107         a = (__force u32)saddr->s6_addr32[0];
 108         b = (__force u32)saddr->s6_addr32[1];
 109         c = (__force u32)saddr->s6_addr32[2];
 110
 111         a += JHASH_GOLDEN_RATIO;
 112         b += JHASH_GOLDEN_RATIO;
 113         c += rnd;
 114         __jhash_mix(a, b, c);
 115
 116         a += (__force u32)saddr->s6_addr32[3];
 117         b += (__force u32)daddr->s6_addr32[0];
 118         c += (__force u32)daddr->s6_addr32[1];
 119         __jhash_mix(a, b, c);
 120
 121         a += (__force u32)daddr->s6_addr32[2];
 122         b += (__force u32)daddr->s6_addr32[3];
 123         c += (__force u32)id;
 124         __jhash_mix(a, b, c);
 125
 126         return c & (INETFRAGS_HASHSZ - 1);
 127 }
 128 EXPORT_SYMBOL_GPL(inet6_hash_frag);
 129
 130 static unsigned int ip6_hashfn(struct inet_frag_queue *q)
 131 {
 132         struct frag_queue *fq;
 133
 134         fq = container_of(q, struct frag_queue, q);
 135         return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr, ip6_frags.rnd);
 136 }
 137
 138 int ip6_frag_match(struct inet_frag_queue *q, void *a)
 139 {
 140         struct frag_queue *fq;
 141         struct ip6_create_arg *arg = a;
 142
 143         fq = container_of(q, struct frag_queue, q);
 144         return (fq->id == arg->id &&
 145                         ipv6_addr_equal(&fq->saddr, arg->src) &&
 146                         ipv6_addr_equal(&fq->daddr, arg->dst));
 147 }
 148 EXPORT_SYMBOL(ip6_frag_match);
 149
 150 /* Memory Tracking Functions. */
 151 static inline void frag_kfree_skb(struct netns_frags *nf,
 152                 struct sk_buff *skb, int *work)
 153 {
 154         if (work)
 155                 *work -= skb->truesize;
 156         atomic_sub(skb->truesize, &nf->mem);
 157         kfree_skb(skb);
 158 }
 159
 160 void ip6_frag_init(struct inet_frag_queue *q, void *a)
 161 {
 162         struct frag_queue *fq = container_of(q, struct frag_queue, q);
 163         struct ip6_create_arg *arg = a;
 164
 165         fq->id = arg->id;
 166         ipv6_addr_copy(&fq->saddr, arg->src);
 167         ipv6_addr_copy(&fq->daddr, arg->dst);
 168 }
 169 EXPORT_SYMBOL(ip6_frag_init);
 170
 171 /* Destruction primitives. */
 172
 173 static __inline__ void fq_put(struct frag_queue *fq)
 174 {
 175         inet_frag_put(&fq->q, &ip6_frags);
 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 net *net, struct inet6_dev *idev)
 187 {
 188         int evicted;
 189
 190         evicted = inet_frag_evictor(&net->ipv6.frags, &ip6_frags);
 191         if (evicted)
 192                 IP6_ADD_STATS_BH(net, idev, IPSTATS_MIB_REASMFAILS, evicted);
 193 }
 194
 195 static void ip6_frag_expire(unsigned long data)
 196 {
 197         struct frag_queue *fq;
 198         struct net_device *dev = NULL;
 199         struct net *net;
 200
 201         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 202
 203         spin_lock(&fq->q.lock);
 204
 205         if (fq->q.last_in & INET_FRAG_COMPLETE)
 206                 goto out;
 207
 208         fq_kill(fq);
 209
 210         net = container_of(fq->q.net, struct net, ipv6.frags);
 211         dev = dev_get_by_index(net, fq->iif);
 212         if (!dev)
 213                 goto out;
 214
 215         rcu_read_lock();
 216         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 217         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 218         rcu_read_unlock();
 219
 220         /* Don't send error if the first segment did not arrive. */
 221         if (!(fq->q.last_in & INET_FRAG_FIRST_IN) || !fq->q.fragments)
 222                 goto out;
 223
 224         /*
 225            But use as source device on which LAST ARRIVED
 226            segment was received. And do not use fq->dev
 227            pointer directly, device might already disappeared.
 228          */
 229         fq->q.fragments->dev = dev;
 230         icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
 231 out:
 232         if (dev)
 233                 dev_put(dev);
 234         spin_unlock(&fq->q.lock);
 235         fq_put(fq);
 236 }
 237
 238 static __inline__ struct frag_queue *
 239 fq_find(struct net *net, __be32 id, struct in6_addr *src, struct in6_addr *dst,
 240         struct inet6_dev *idev)
 241 {
 242         struct inet_frag_queue *q;
 243         struct ip6_create_arg arg;
 244         unsigned int hash;
 245
 246         arg.id = id;
 247         arg.src = src;
 248         arg.dst = dst;
 249
 250         read_lock(&ip6_frags.lock);
 251         hash = inet6_hash_frag(id, src, dst, ip6_frags.rnd);
 252
 253         q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
 254         if (q == NULL)
 255                 goto oom;
 256
 257         return container_of(q, struct frag_queue, q);
 258
 259 oom:
 260         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_REASMFAILS);
 261         return NULL;
 262 }
 263
 264 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 265                            struct frag_hdr *fhdr, int nhoff)
 266 {
 267         struct sk_buff *prev, *next;
 268         struct net_device *dev;
 269         int offset, end;
 270         struct net *net = dev_net(skb_dst(skb)->dev);
 271
 272         if (fq->q.last_in & INET_FRAG_COMPLETE)
 273                 goto err;
 274
 275         offset = ntohs(fhdr->frag_off) & ~0x7;
 276         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 277                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 278
 279         if ((unsigned int)end > IPV6_MAXPLEN) {
 280                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 281                                  IPSTATS_MIB_INHDRERRORS);
 282                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 283                                   ((u8 *)&fhdr->frag_off -
 284                                    skb_network_header(skb)));
 285                 return -1;
 286         }
 287
 288         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 289                 const unsigned char *nh = skb_network_header(skb);
 290                 skb->csum = csum_sub(skb->csum,
 291                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 292                                                   0));
 293         }
 294
 295         /* Is this the final fragment? */
 296         if (!(fhdr->frag_off & htons(IP6_MF))) {
 297                 /* If we already have some bits beyond end
 298                  * or have different end, the segment is corrupted.
 299                  */
 300                 if (end < fq->q.len ||
 301                     ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
 302                         goto err;
 303                 fq->q.last_in |= INET_FRAG_LAST_IN;
 304                 fq->q.len = end;
 305         } else {
 306                 /* Check if the fragment is rounded to 8 bytes.
 307                  * Required by the RFC.
 308                  */
 309                 if (end & 0x7) {
 310                         /* RFC2460 says always send parameter problem in
 311                          * this case. -DaveM
 312                          */
 313                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 314                                          IPSTATS_MIB_INHDRERRORS);
 315                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 316                                           offsetof(struct ipv6hdr, payload_len));
 317                         return -1;
 318                 }
 319                 if (end > fq->q.len) {
 320                         /* Some bits beyond end -> corruption. */
 321                         if (fq->q.last_in & INET_FRAG_LAST_IN)
 322                                 goto err;
 323                         fq->q.len = end;
 324                 }
 325         }
 326
 327         if (end == offset)
 328                 goto err;
 329
 330         /* Point into the IP datagram 'data' part. */
 331         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 332                 goto err;
 333
 334         if (pskb_trim_rcsum(skb, end - offset))
 335                 goto err;
 336
 337         /* Find out which fragments are in front and at the back of us
 338          * in the chain of fragments so far.  We must know where to put
 339          * this fragment, right?
 340          */
 341         prev = NULL;
 342         for(next = fq->q.fragments; next != NULL; next = next->next) {
 343                 if (FRAG6_CB(next)->offset >= offset)
 344                         break;  /* bingo! */
 345                 prev = next;
 346         }
 347
 348         /* We found where to put this one.  Check for overlap with
 349          * preceding fragment, and, if needed, align things so that
 350          * any overlaps are eliminated.
 351          */
 352         if (prev) {
 353                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
 354
 355                 if (i > 0) {
 356                         offset += i;
 357                         if (end <= offset)
 358                                 goto err;
 359                         if (!pskb_pull(skb, i))
 360                                 goto err;
 361                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 362                                 skb->ip_summed = CHECKSUM_NONE;
 363                 }
 364         }
 365
 366         /* Look for overlap with succeeding segments.
 367          * If we can merge fragments, do it.
 368          */
 369         while (next && FRAG6_CB(next)->offset < end) {
 370                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
 371
 372                 if (i < next->len) {
 373                         /* Eat head of the next overlapped fragment
 374                          * and leave the loop. The next ones cannot overlap.
 375                          */
 376                         if (!pskb_pull(next, i))
 377                                 goto err;
 378                         FRAG6_CB(next)->offset += i;    /* next fragment */
 379                         fq->q.meat -= i;
 380                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 381                                 next->ip_summed = CHECKSUM_NONE;
 382                         break;
 383                 } else {
 384                         struct sk_buff *free_it = next;
 385
 386                         /* Old fragment is completely overridden with
 387                          * new one drop it.
 388                          */
 389                         next = next->next;
 390
 391                         if (prev)
 392                                 prev->next = next;
 393                         else
 394                                 fq->q.fragments = next;
 395
 396                         fq->q.meat -= free_it->len;
 397                         frag_kfree_skb(fq->q.net, free_it, NULL);
 398                 }
 399         }
 400
 401         FRAG6_CB(skb)->offset = offset;
 402
 403         /* Insert this fragment in the chain of fragments. */
 404         skb->next = next;
 405         if (prev)
 406                 prev->next = skb;
 407         else
 408                 fq->q.fragments = skb;
 409
 410         dev = skb->dev;
 411         if (dev) {
 412                 fq->iif = dev->ifindex;
 413                 skb->dev = NULL;
 414         }
 415         fq->q.stamp = skb->tstamp;
 416         fq->q.meat += skb->len;
 417         atomic_add(skb->truesize, &fq->q.net->mem);
 418
 419         /* The first fragment.
 420          * nhoffset is obtained from the first fragment, of course.
 421          */
 422         if (offset == 0) {
 423                 fq->nhoffset = nhoff;
 424                 fq->q.last_in |= INET_FRAG_FIRST_IN;
 425         }
 426
 427         if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 428             fq->q.meat == fq->q.len)
 429                 return ip6_frag_reasm(fq, prev, dev);
 430
 431         write_lock(&ip6_frags.lock);
 432         list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
 433         write_unlock(&ip6_frags.lock);
 434         return -1;
 435
 436 err:
 437         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 438                       IPSTATS_MIB_REASMFAILS);
 439         kfree_skb(skb);
 440         return -1;
 441 }
 442
 443 /*
 444  *      Check if this packet is complete.
 445  *      Returns NULL on failure by any reason, and pointer
 446  *      to current nexthdr field in reassembled frame.
 447  *
 448  *      It is called with locked fq, and caller must check that
 449  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 450  *      the last and the first frames arrived and all the bits are here.
 451  */
 452 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 453                           struct net_device *dev)
 454 {
 455         struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
 456         struct sk_buff *fp, *head = fq->q.fragments;
 457         int    payload_len;
 458         unsigned int nhoff;
 459
 460         fq_kill(fq);
 461
 462         /* Make the one we just received the head. */
 463         if (prev) {
 464                 head = prev->next;
 465                 fp = skb_clone(head, GFP_ATOMIC);
 466
 467                 if (!fp)
 468                         goto out_oom;
 469
 470                 fp->next = head->next;
 471                 prev->next = fp;
 472
 473                 skb_morph(head, fq->q.fragments);
 474                 head->next = fq->q.fragments->next;
 475
 476                 kfree_skb(fq->q.fragments);
 477                 fq->q.fragments = head;
 478         }
 479
 480         WARN_ON(head == NULL);
 481         WARN_ON(FRAG6_CB(head)->offset != 0);
 482
 483         /* Unfragmented part is taken from the first segment. */
 484         payload_len = ((head->data - skb_network_header(head)) -
 485                        sizeof(struct ipv6hdr) + fq->q.len -
 486                        sizeof(struct frag_hdr));
 487         if (payload_len > IPV6_MAXPLEN)
 488                 goto out_oversize;
 489
 490         /* Head of list must not be cloned. */
 491         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 492                 goto out_oom;
 493
 494         /* If the first fragment is fragmented itself, we split
 495          * it to two chunks: the first with data and paged part
 496          * and the second, holding only fragments. */
 497         if (skb_has_frags(head)) {
 498                 struct sk_buff *clone;
 499                 int i, plen = 0;
 500
 501                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 502                         goto out_oom;
 503                 clone->next = head->next;
 504                 head->next = clone;
 505                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 506                 skb_frag_list_init(head);
 507                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 508                         plen += skb_shinfo(head)->frags[i].size;
 509                 clone->len = clone->data_len = head->data_len - plen;
 510                 head->data_len -= clone->len;
 511                 head->len -= clone->len;
 512                 clone->csum = 0;
 513                 clone->ip_summed = head->ip_summed;
 514                 atomic_add(clone->truesize, &fq->q.net->mem);
 515         }
 516
 517         /* We have to remove fragment header from datagram and to relocate
 518          * header in order to calculate ICV correctly. */
 519         nhoff = fq->nhoffset;
 520         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 521         memmove(head->head + sizeof(struct frag_hdr), head->head,
 522                 (head->data - head->head) - sizeof(struct frag_hdr));
 523         head->mac_header += sizeof(struct frag_hdr);
 524         head->network_header += sizeof(struct frag_hdr);
 525
 526         skb_shinfo(head)->frag_list = head->next;
 527         skb_reset_transport_header(head);
 528         skb_push(head, head->data - skb_network_header(head));
 529         atomic_sub(head->truesize, &fq->q.net->mem);
 530
 531         for (fp=head->next; fp; fp = fp->next) {
 532                 head->data_len += fp->len;
 533                 head->len += fp->len;
 534                 if (head->ip_summed != fp->ip_summed)
 535                         head->ip_summed = CHECKSUM_NONE;
 536                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 537                         head->csum = csum_add(head->csum, fp->csum);
 538                 head->truesize += fp->truesize;
 539                 atomic_sub(fp->truesize, &fq->q.net->mem);
 540         }
 541
 542         head->next = NULL;
 543         head->dev = dev;
 544         head->tstamp = fq->q.stamp;
 545         ipv6_hdr(head)->payload_len = htons(payload_len);
 546         IP6CB(head)->nhoff = nhoff;
 547
 548         /* Yes, and fold redundant checksum back. 8) */
 549         if (head->ip_summed == CHECKSUM_COMPLETE)
 550                 head->csum = csum_partial(skb_network_header(head),
 551                                           skb_network_header_len(head),
 552                                           head->csum);
 553
 554         rcu_read_lock();
 555         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 556         rcu_read_unlock();
 557         fq->q.fragments = NULL;
 558         return 1;
 559
 560 out_oversize:
 561         if (net_ratelimit())
 562                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
 563         goto out_fail;
 564 out_oom:
 565         if (net_ratelimit())
 566                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
 567 out_fail:
 568         rcu_read_lock();
 569         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 570         rcu_read_unlock();
 571         return -1;
 572 }
 573
 574 static int ipv6_frag_rcv(struct sk_buff *skb)
 575 {
 576         struct frag_hdr *fhdr;
 577         struct frag_queue *fq;
 578         struct ipv6hdr *hdr = ipv6_hdr(skb);
 579         struct net *net = dev_net(skb_dst(skb)->dev);
 580
 581         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
 582
 583         /* Jumbo payload inhibits frag. header */
 584         if (hdr->payload_len==0)
 585                 goto fail_hdr;
 586
 587         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 588                                  sizeof(struct frag_hdr))))
 589                 goto fail_hdr;
 590
 591         hdr = ipv6_hdr(skb);
 592         fhdr = (struct frag_hdr *)skb_transport_header(skb);
 593
 594         if (!(fhdr->frag_off & htons(0xFFF9))) {
 595                 /* It is not a fragmented frame */
 596                 skb->transport_header += sizeof(struct frag_hdr);
 597                 IP6_INC_STATS_BH(net,
 598                                  ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
 599
 600                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 601                 return 1;
 602         }
 603
 604         if (atomic_read(&net->ipv6.frags.mem) > net->ipv6.frags.high_thresh)
 605                 ip6_evictor(net, ip6_dst_idev(skb_dst(skb)));
 606
 607         if ((fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
 608                           ip6_dst_idev(skb_dst(skb)))) != NULL) {
 609                 int ret;
 610
 611                 spin_lock(&fq->q.lock);
 612
 613                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 614
 615                 spin_unlock(&fq->q.lock);
 616                 fq_put(fq);
 617                 return ret;
 618         }
 619
 620         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
 621         kfree_skb(skb);
 622         return -1;
 623
 624 fail_hdr:
 625         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
 626         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
 627         return -1;
 628 }
 629
 630 static struct inet6_protocol frag_protocol =
 631 {
 632         .handler        =       ipv6_frag_rcv,
 633         .flags          =       INET6_PROTO_NOPOLICY,
 634 };
 635
 636 #ifdef CONFIG_SYSCTL
 637 static struct ctl_table ip6_frags_ns_ctl_table[] = {
 638         {
 639                 .ctl_name       = NET_IPV6_IP6FRAG_HIGH_THRESH,
 640                 .procname       = "ip6frag_high_thresh",
 641                 .data           = &init_net.ipv6.frags.high_thresh,
 642                 .maxlen         = sizeof(int),
 643                 .mode           = 0644,
 644                 .proc_handler   = proc_dointvec
 645         },
 646         {
 647                 .ctl_name       = NET_IPV6_IP6FRAG_LOW_THRESH,
 648                 .procname       = "ip6frag_low_thresh",
 649                 .data           = &init_net.ipv6.frags.low_thresh,
 650                 .maxlen         = sizeof(int),
 651                 .mode           = 0644,
 652                 .proc_handler   = proc_dointvec
 653         },
 654         {
 655                 .ctl_name       = NET_IPV6_IP6FRAG_TIME,
 656                 .procname       = "ip6frag_time",
 657                 .data           = &init_net.ipv6.frags.timeout,
 658                 .maxlen         = sizeof(int),
 659                 .mode           = 0644,
 660                 .proc_handler   = proc_dointvec_jiffies,
 661                 .strategy       = sysctl_jiffies,
 662         },
 663         { }
 664 };
 665
 666 static struct ctl_table ip6_frags_ctl_table[] = {
 667         {
 668                 .ctl_name       = NET_IPV6_IP6FRAG_SECRET_INTERVAL,
 669                 .procname       = "ip6frag_secret_interval",
 670                 .data           = &ip6_frags.secret_interval,
 671                 .maxlen         = sizeof(int),
 672                 .mode           = 0644,
 673                 .proc_handler   = proc_dointvec_jiffies,
 674                 .strategy       = sysctl_jiffies
 675         },
 676         { }
 677 };
 678
 679 static int ip6_frags_ns_sysctl_register(struct net *net)
 680 {
 681         struct ctl_table *table;
 682         struct ctl_table_header *hdr;
 683
 684         table = ip6_frags_ns_ctl_table;
 685         if (net != &init_net) {
 686                 table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
 687                 if (table == NULL)
 688                         goto err_alloc;
 689
 690                 table[0].data = &net->ipv6.frags.high_thresh;
 691                 table[1].data = &net->ipv6.frags.low_thresh;
 692                 table[2].data = &net->ipv6.frags.timeout;
 693         }
 694
 695         hdr = register_net_sysctl_table(net, net_ipv6_ctl_path, table);
 696         if (hdr == NULL)
 697                 goto err_reg;
 698
 699         net->ipv6.sysctl.frags_hdr = hdr;
 700         return 0;
 701
 702 err_reg:
 703         if (net != &init_net)
 704                 kfree(table);
 705 err_alloc:
 706         return -ENOMEM;
 707 }
 708
 709 static void ip6_frags_ns_sysctl_unregister(struct net *net)
 710 {
 711         struct ctl_table *table;
 712
 713         table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
 714         unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
 715         kfree(table);
 716 }
 717
 718 static struct ctl_table_header *ip6_ctl_header;
 719
 720 static int ip6_frags_sysctl_register(void)
 721 {
 722         ip6_ctl_header = register_net_sysctl_rotable(net_ipv6_ctl_path,
 723                         ip6_frags_ctl_table);
 724         return ip6_ctl_header == NULL ? -ENOMEM : 0;
 725 }
 726
 727 static void ip6_frags_sysctl_unregister(void)
 728 {
 729         unregister_net_sysctl_table(ip6_ctl_header);
 730 }
 731 #else
 732 static inline int ip6_frags_ns_sysctl_register(struct net *net)
 733 {
 734         return 0;
 735 }
 736
 737 static inline void ip6_frags_ns_sysctl_unregister(struct net *net)
 738 {
 739 }
 740
 741 static inline int ip6_frags_sysctl_register(void)
 742 {
 743         return 0;
 744 }
 745
 746 static inline void ip6_frags_sysctl_unregister(void)
 747 {
 748 }
 749 #endif
 750
 751 static int ipv6_frags_init_net(struct net *net)
 752 {
 753         net->ipv6.frags.high_thresh = 256 * 1024;
 754         net->ipv6.frags.low_thresh = 192 * 1024;
 755         net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
 756
 757         inet_frags_init_net(&net->ipv6.frags);
 758
 759         return ip6_frags_ns_sysctl_register(net);
 760 }
 761
 762 static void ipv6_frags_exit_net(struct net *net)
 763 {
 764         ip6_frags_ns_sysctl_unregister(net);
 765         inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
 766 }
 767
 768 static struct pernet_operations ip6_frags_ops = {
 769         .init = ipv6_frags_init_net,
 770         .exit = ipv6_frags_exit_net,
 771 };
 772
 773 int __init ipv6_frag_init(void)
 774 {
 775         int ret;
 776
 777         ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 778         if (ret)
 779                 goto out;
 780
 781         ret = ip6_frags_sysctl_register();
 782         if (ret)
 783                 goto err_sysctl;
 784
 785         ret = register_pernet_subsys(&ip6_frags_ops);
 786         if (ret)
 787                 goto err_pernet;
 788
 789         ip6_frags.hashfn = ip6_hashfn;
 790         ip6_frags.constructor = ip6_frag_init;
 791         ip6_frags.destructor = NULL;
 792         ip6_frags.skb_free = NULL;
 793         ip6_frags.qsize = sizeof(struct frag_queue);
 794         ip6_frags.match = ip6_frag_match;
 795         ip6_frags.frag_expire = ip6_frag_expire;
 796         ip6_frags.secret_interval = 10 * 60 * HZ;
 797         inet_frags_init(&ip6_frags);
 798 out:
 799         return ret;
 800
 801 err_pernet:
 802         ip6_frags_sysctl_unregister();
 803 err_sysctl:
 804         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 805         goto out;
 806 }
 807
 808 void ipv6_frag_exit(void)
 809 {
 810         inet_frags_fini(&ip6_frags);
 811         ip6_frags_sysctl_unregister();
 812         unregister_pernet_subsys(&ip6_frags_ops);
 813         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 814 }