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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  *      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         u32                     user;
  76         struct in6_addr         saddr;
  77         struct in6_addr         daddr;
  78
  79         int                     iif;
  80         unsigned int            csum;
  81         __u16                   nhoffset;
  82 };
  83
  84 static struct inet_frags ip6_frags;
  85
  86 int ip6_frag_nqueues(struct net *net)
  87 {
  88         return net->ipv6.frags.nqueues;
  89 }
  90
  91 int ip6_frag_mem(struct net *net)
  92 {
  93         return atomic_read(&net->ipv6.frags.mem);
  94 }
  95
  96 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
  97                           struct net_device *dev);
  98
  99 /*
 100  * callers should be careful not to use the hash value outside the ipfrag_lock
 101  * as doing so could race with ipfrag_hash_rnd being recalculated.
 102  */
 103 unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
 104                              const struct in6_addr *daddr, u32 rnd)
 105 {
 106         u32 a, b, c;
 107
 108         a = (__force u32)saddr->s6_addr32[0];
 109         b = (__force u32)saddr->s6_addr32[1];
 110         c = (__force u32)saddr->s6_addr32[2];
 111
 112         a += JHASH_GOLDEN_RATIO;
 113         b += JHASH_GOLDEN_RATIO;
 114         c += rnd;
 115         __jhash_mix(a, b, c);
 116
 117         a += (__force u32)saddr->s6_addr32[3];
 118         b += (__force u32)daddr->s6_addr32[0];
 119         c += (__force u32)daddr->s6_addr32[1];
 120         __jhash_mix(a, b, c);
 121
 122         a += (__force u32)daddr->s6_addr32[2];
 123         b += (__force u32)daddr->s6_addr32[3];
 124         c += (__force u32)id;
 125         __jhash_mix(a, b, c);
 126
 127         return c & (INETFRAGS_HASHSZ - 1);
 128 }
 129 EXPORT_SYMBOL_GPL(inet6_hash_frag);
 130
 131 static unsigned int ip6_hashfn(struct inet_frag_queue *q)
 132 {
 133         struct frag_queue *fq;
 134
 135         fq = container_of(q, struct frag_queue, q);
 136         return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr, ip6_frags.rnd);
 137 }
 138
 139 int ip6_frag_match(struct inet_frag_queue *q, void *a)
 140 {
 141         struct frag_queue *fq;
 142         struct ip6_create_arg *arg = a;
 143
 144         fq = container_of(q, struct frag_queue, q);
 145         return (fq->id == arg->id && fq->user == arg->user &&
 146                         ipv6_addr_equal(&fq->saddr, arg->src) &&
 147                         ipv6_addr_equal(&fq->daddr, arg->dst));
 148 }
 149 EXPORT_SYMBOL(ip6_frag_match);
 150
 151 /* Memory Tracking Functions. */
 152 static inline void frag_kfree_skb(struct netns_frags *nf,
 153                 struct sk_buff *skb, int *work)
 154 {
 155         if (work)
 156                 *work -= skb->truesize;
 157         atomic_sub(skb->truesize, &nf->mem);
 158         kfree_skb(skb);
 159 }
 160
 161 void ip6_frag_init(struct inet_frag_queue *q, void *a)
 162 {
 163         struct frag_queue *fq = container_of(q, struct frag_queue, q);
 164         struct ip6_create_arg *arg = a;
 165
 166         fq->id = arg->id;
 167         fq->user = arg->user;
 168         ipv6_addr_copy(&fq->saddr, arg->src);
 169         ipv6_addr_copy(&fq->daddr, arg->dst);
 170 }
 171 EXPORT_SYMBOL(ip6_frag_init);
 172
 173 /* Destruction primitives. */
 174
 175 static __inline__ void fq_put(struct frag_queue *fq)
 176 {
 177         inet_frag_put(&fq->q, &ip6_frags);
 178 }
 179
 180 /* Kill fq entry. It is not destroyed immediately,
 181  * because caller (and someone more) holds reference count.
 182  */
 183 static __inline__ void fq_kill(struct frag_queue *fq)
 184 {
 185         inet_frag_kill(&fq->q, &ip6_frags);
 186 }
 187
 188 static void ip6_evictor(struct net *net, struct inet6_dev *idev)
 189 {
 190         int evicted;
 191
 192         evicted = inet_frag_evictor(&net->ipv6.frags, &ip6_frags);
 193         if (evicted)
 194                 IP6_ADD_STATS_BH(net, idev, IPSTATS_MIB_REASMFAILS, evicted);
 195 }
 196
 197 static void ip6_frag_expire(unsigned long data)
 198 {
 199         struct frag_queue *fq;
 200         struct net_device *dev = NULL;
 201         struct net *net;
 202
 203         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 204
 205         spin_lock(&fq->q.lock);
 206
 207         if (fq->q.last_in & INET_FRAG_COMPLETE)
 208                 goto out;
 209
 210         fq_kill(fq);
 211
 212         net = container_of(fq->q.net, struct net, ipv6.frags);
 213         rcu_read_lock();
 214         dev = dev_get_by_index_rcu(net, fq->iif);
 215         if (!dev)
 216                 goto out_rcu_unlock;
 217
 218         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 219         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 220
 221         /* Don't send error if the first segment did not arrive. */
 222         if (!(fq->q.last_in & INET_FRAG_FIRST_IN) || !fq->q.fragments)
 223                 goto out_rcu_unlock;
 224
 225         /*
 226            But use as source device on which LAST ARRIVED
 227            segment was received. And do not use fq->dev
 228            pointer directly, device might already disappeared.
 229          */
 230         fq->q.fragments->dev = dev;
 231         icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
 232 out_rcu_unlock:
 233         rcu_read_unlock();
 234 out:
 235         spin_unlock(&fq->q.lock);
 236         fq_put(fq);
 237 }
 238
 239 static __inline__ struct frag_queue *
 240 fq_find(struct net *net, __be32 id, struct in6_addr *src, struct in6_addr *dst,
 241         struct inet6_dev *idev)
 242 {
 243         struct inet_frag_queue *q;
 244         struct ip6_create_arg arg;
 245         unsigned int hash;
 246
 247         arg.id = id;
 248         arg.user = IP6_DEFRAG_LOCAL_DELIVER;
 249         arg.src = src;
 250         arg.dst = dst;
 251
 252         read_lock(&ip6_frags.lock);
 253         hash = inet6_hash_frag(id, src, dst, ip6_frags.rnd);
 254
 255         q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
 256         if (q == NULL)
 257                 goto oom;
 258
 259         return container_of(q, struct frag_queue, q);
 260
 261 oom:
 262         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_REASMFAILS);
 263         return NULL;
 264 }
 265
 266 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 267                            struct frag_hdr *fhdr, int nhoff)
 268 {
 269         struct sk_buff *prev, *next;
 270         struct net_device *dev;
 271         int offset, end;
 272         struct net *net = dev_net(skb_dst(skb)->dev);
 273
 274         if (fq->q.last_in & INET_FRAG_COMPLETE)
 275                 goto err;
 276
 277         offset = ntohs(fhdr->frag_off) & ~0x7;
 278         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 279                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 280
 281         if ((unsigned int)end > IPV6_MAXPLEN) {
 282                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 283                                  IPSTATS_MIB_INHDRERRORS);
 284                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 285                                   ((u8 *)&fhdr->frag_off -
 286                                    skb_network_header(skb)));
 287                 return -1;
 288         }
 289
 290         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 291                 const unsigned char *nh = skb_network_header(skb);
 292                 skb->csum = csum_sub(skb->csum,
 293                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 294                                                   0));
 295         }
 296
 297         /* Is this the final fragment? */
 298         if (!(fhdr->frag_off & htons(IP6_MF))) {
 299                 /* If we already have some bits beyond end
 300                  * or have different end, the segment is corrupted.
 301                  */
 302                 if (end < fq->q.len ||
 303                     ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
 304                         goto err;
 305                 fq->q.last_in |= INET_FRAG_LAST_IN;
 306                 fq->q.len = end;
 307         } else {
 308                 /* Check if the fragment is rounded to 8 bytes.
 309                  * Required by the RFC.
 310                  */
 311                 if (end & 0x7) {
 312                         /* RFC2460 says always send parameter problem in
 313                          * this case. -DaveM
 314                          */
 315                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 316                                          IPSTATS_MIB_INHDRERRORS);
 317                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 318                                           offsetof(struct ipv6hdr, payload_len));
 319                         return -1;
 320                 }
 321                 if (end > fq->q.len) {
 322                         /* Some bits beyond end -> corruption. */
 323                         if (fq->q.last_in & INET_FRAG_LAST_IN)
 324                                 goto err;
 325                         fq->q.len = end;
 326                 }
 327         }
 328
 329         if (end == offset)
 330                 goto err;
 331
 332         /* Point into the IP datagram 'data' part. */
 333         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 334                 goto err;
 335
 336         if (pskb_trim_rcsum(skb, end - offset))
 337                 goto err;
 338
 339         /* Find out which fragments are in front and at the back of us
 340          * in the chain of fragments so far.  We must know where to put
 341          * this fragment, right?
 342          */
 343         prev = NULL;
 344         for(next = fq->q.fragments; next != NULL; next = next->next) {
 345                 if (FRAG6_CB(next)->offset >= offset)
 346                         break;  /* bingo! */
 347                 prev = next;
 348         }
 349
 350         /* We found where to put this one.  Check for overlap with
 351          * preceding fragment, and, if needed, align things so that
 352          * any overlaps are eliminated.
 353          */
 354         if (prev) {
 355                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
 356
 357                 if (i > 0) {
 358                         offset += i;
 359                         if (end <= offset)
 360                                 goto err;
 361                         if (!pskb_pull(skb, i))
 362                                 goto err;
 363                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 364                                 skb->ip_summed = CHECKSUM_NONE;
 365                 }
 366         }
 367
 368         /* Look for overlap with succeeding segments.
 369          * If we can merge fragments, do it.
 370          */
 371         while (next && FRAG6_CB(next)->offset < end) {
 372                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
 373
 374                 if (i < next->len) {
 375                         /* Eat head of the next overlapped fragment
 376                          * and leave the loop. The next ones cannot overlap.
 377                          */
 378                         if (!pskb_pull(next, i))
 379                                 goto err;
 380                         FRAG6_CB(next)->offset += i;    /* next fragment */
 381                         fq->q.meat -= i;
 382                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 383                                 next->ip_summed = CHECKSUM_NONE;
 384                         break;
 385                 } else {
 386                         struct sk_buff *free_it = next;
 387
 388                         /* Old fragment is completely overridden with
 389                          * new one drop it.
 390                          */
 391                         next = next->next;
 392
 393                         if (prev)
 394                                 prev->next = next;
 395                         else
 396                                 fq->q.fragments = next;
 397
 398                         fq->q.meat -= free_it->len;
 399                         frag_kfree_skb(fq->q.net, free_it, NULL);
 400                 }
 401         }
 402
 403         FRAG6_CB(skb)->offset = offset;
 404
 405         /* Insert this fragment in the chain of fragments. */
 406         skb->next = next;
 407         if (prev)
 408                 prev->next = skb;
 409         else
 410                 fq->q.fragments = skb;
 411
 412         dev = skb->dev;
 413         if (dev) {
 414                 fq->iif = dev->ifindex;
 415                 skb->dev = NULL;
 416         }
 417         fq->q.stamp = skb->tstamp;
 418         fq->q.meat += skb->len;
 419         atomic_add(skb->truesize, &fq->q.net->mem);
 420
 421         /* The first fragment.
 422          * nhoffset is obtained from the first fragment, of course.
 423          */
 424         if (offset == 0) {
 425                 fq->nhoffset = nhoff;
 426                 fq->q.last_in |= INET_FRAG_FIRST_IN;
 427         }
 428
 429         if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 430             fq->q.meat == fq->q.len)
 431                 return ip6_frag_reasm(fq, prev, dev);
 432
 433         write_lock(&ip6_frags.lock);
 434         list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
 435         write_unlock(&ip6_frags.lock);
 436         return -1;
 437
 438 err:
 439         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 440                       IPSTATS_MIB_REASMFAILS);
 441         kfree_skb(skb);
 442         return -1;
 443 }
 444
 445 /*
 446  *      Check if this packet is complete.
 447  *      Returns NULL on failure by any reason, and pointer
 448  *      to current nexthdr field in reassembled frame.
 449  *
 450  *      It is called with locked fq, and caller must check that
 451  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 452  *      the last and the first frames arrived and all the bits are here.
 453  */
 454 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 455                           struct net_device *dev)
 456 {
 457         struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
 458         struct sk_buff *fp, *head = fq->q.fragments;
 459         int    payload_len;
 460         unsigned int nhoff;
 461
 462         fq_kill(fq);
 463
 464         /* Make the one we just received the head. */
 465         if (prev) {
 466                 head = prev->next;
 467                 fp = skb_clone(head, GFP_ATOMIC);
 468
 469                 if (!fp)
 470                         goto out_oom;
 471
 472                 fp->next = head->next;
 473                 prev->next = fp;
 474
 475                 skb_morph(head, fq->q.fragments);
 476                 head->next = fq->q.fragments->next;
 477
 478                 kfree_skb(fq->q.fragments);
 479                 fq->q.fragments = head;
 480         }
 481
 482         WARN_ON(head == NULL);
 483         WARN_ON(FRAG6_CB(head)->offset != 0);
 484
 485         /* Unfragmented part is taken from the first segment. */
 486         payload_len = ((head->data - skb_network_header(head)) -
 487                        sizeof(struct ipv6hdr) + fq->q.len -
 488                        sizeof(struct frag_hdr));
 489         if (payload_len > IPV6_MAXPLEN)
 490                 goto out_oversize;
 491
 492         /* Head of list must not be cloned. */
 493         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 494                 goto out_oom;
 495
 496         /* If the first fragment is fragmented itself, we split
 497          * it to two chunks: the first with data and paged part
 498          * and the second, holding only fragments. */
 499         if (skb_has_frags(head)) {
 500                 struct sk_buff *clone;
 501                 int i, plen = 0;
 502
 503                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 504                         goto out_oom;
 505                 clone->next = head->next;
 506                 head->next = clone;
 507                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 508                 skb_frag_list_init(head);
 509                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 510                         plen += skb_shinfo(head)->frags[i].size;
 511                 clone->len = clone->data_len = head->data_len - plen;
 512                 head->data_len -= clone->len;
 513                 head->len -= clone->len;
 514                 clone->csum = 0;
 515                 clone->ip_summed = head->ip_summed;
 516                 atomic_add(clone->truesize, &fq->q.net->mem);
 517         }
 518
 519         /* We have to remove fragment header from datagram and to relocate
 520          * header in order to calculate ICV correctly. */
 521         nhoff = fq->nhoffset;
 522         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 523         memmove(head->head + sizeof(struct frag_hdr), head->head,
 524                 (head->data - head->head) - sizeof(struct frag_hdr));
 525         head->mac_header += sizeof(struct frag_hdr);
 526         head->network_header += sizeof(struct frag_hdr);
 527
 528         skb_shinfo(head)->frag_list = head->next;
 529         skb_reset_transport_header(head);
 530         skb_push(head, head->data - skb_network_header(head));
 531         atomic_sub(head->truesize, &fq->q.net->mem);
 532
 533         for (fp=head->next; fp; fp = fp->next) {
 534                 head->data_len += fp->len;
 535                 head->len += fp->len;
 536                 if (head->ip_summed != fp->ip_summed)
 537                         head->ip_summed = CHECKSUM_NONE;
 538                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 539                         head->csum = csum_add(head->csum, fp->csum);
 540                 head->truesize += fp->truesize;
 541                 atomic_sub(fp->truesize, &fq->q.net->mem);
 542         }
 543
 544         head->next = NULL;
 545         head->dev = dev;
 546         head->tstamp = fq->q.stamp;
 547         ipv6_hdr(head)->payload_len = htons(payload_len);
 548         IP6CB(head)->nhoff = nhoff;
 549
 550         /* Yes, and fold redundant checksum back. 8) */
 551         if (head->ip_summed == CHECKSUM_COMPLETE)
 552                 head->csum = csum_partial(skb_network_header(head),
 553                                           skb_network_header_len(head),
 554                                           head->csum);
 555
 556         rcu_read_lock();
 557         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 558         rcu_read_unlock();
 559         fq->q.fragments = NULL;
 560         return 1;
 561
 562 out_oversize:
 563         if (net_ratelimit())
 564                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
 565         goto out_fail;
 566 out_oom:
 567         if (net_ratelimit())
 568                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
 569 out_fail:
 570         rcu_read_lock();
 571         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 572         rcu_read_unlock();
 573         return -1;
 574 }
 575
 576 static int ipv6_frag_rcv(struct sk_buff *skb)
 577 {
 578         struct frag_hdr *fhdr;
 579         struct frag_queue *fq;
 580         struct ipv6hdr *hdr = ipv6_hdr(skb);
 581         struct net *net = dev_net(skb_dst(skb)->dev);
 582
 583         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
 584
 585         /* Jumbo payload inhibits frag. header */
 586         if (hdr->payload_len==0)
 587                 goto fail_hdr;
 588
 589         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 590                                  sizeof(struct frag_hdr))))
 591                 goto fail_hdr;
 592
 593         hdr = ipv6_hdr(skb);
 594         fhdr = (struct frag_hdr *)skb_transport_header(skb);
 595
 596         if (!(fhdr->frag_off & htons(0xFFF9))) {
 597                 /* It is not a fragmented frame */
 598                 skb->transport_header += sizeof(struct frag_hdr);
 599                 IP6_INC_STATS_BH(net,
 600                                  ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
 601
 602                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 603                 return 1;
 604         }
 605
 606         if (atomic_read(&net->ipv6.frags.mem) > net->ipv6.frags.high_thresh)
 607                 ip6_evictor(net, ip6_dst_idev(skb_dst(skb)));
 608
 609         if ((fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
 610                           ip6_dst_idev(skb_dst(skb)))) != NULL) {
 611                 int ret;
 612
 613                 spin_lock(&fq->q.lock);
 614
 615                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 616
 617                 spin_unlock(&fq->q.lock);
 618                 fq_put(fq);
 619                 return ret;
 620         }
 621
 622         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
 623         kfree_skb(skb);
 624         return -1;
 625
 626 fail_hdr:
 627         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
 628         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
 629         return -1;
 630 }
 631
 632 static const struct inet6_protocol frag_protocol =
 633 {
 634         .handler        =       ipv6_frag_rcv,
 635         .flags          =       INET6_PROTO_NOPOLICY,
 636 };
 637
 638 #ifdef CONFIG_SYSCTL
 639 static struct ctl_table ip6_frags_ns_ctl_table[] = {
 640         {
 641                 .procname       = "ip6frag_high_thresh",
 642                 .data           = &init_net.ipv6.frags.high_thresh,
 643                 .maxlen         = sizeof(int),
 644                 .mode           = 0644,
 645                 .proc_handler   = proc_dointvec
 646         },
 647         {
 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                 .procname       = "ip6frag_time",
 656                 .data           = &init_net.ipv6.frags.timeout,
 657                 .maxlen         = sizeof(int),
 658                 .mode           = 0644,
 659                 .proc_handler   = proc_dointvec_jiffies,
 660         },
 661         { }
 662 };
 663
 664 static struct ctl_table ip6_frags_ctl_table[] = {
 665         {
 666                 .procname       = "ip6frag_secret_interval",
 667                 .data           = &ip6_frags.secret_interval,
 668                 .maxlen         = sizeof(int),
 669                 .mode           = 0644,
 670                 .proc_handler   = proc_dointvec_jiffies,
 671         },
 672         { }
 673 };
 674
 675 static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
 676 {
 677         struct ctl_table *table;
 678         struct ctl_table_header *hdr;
 679
 680         table = ip6_frags_ns_ctl_table;
 681         if (!net_eq(net, &init_net)) {
 682                 table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
 683                 if (table == NULL)
 684                         goto err_alloc;
 685
 686                 table[0].data = &net->ipv6.frags.high_thresh;
 687                 table[1].data = &net->ipv6.frags.low_thresh;
 688                 table[2].data = &net->ipv6.frags.timeout;
 689         }
 690
 691         hdr = register_net_sysctl_table(net, net_ipv6_ctl_path, table);
 692         if (hdr == NULL)
 693                 goto err_reg;
 694
 695         net->ipv6.sysctl.frags_hdr = hdr;
 696         return 0;
 697
 698 err_reg:
 699         if (!net_eq(net, &init_net))
 700                 kfree(table);
 701 err_alloc:
 702         return -ENOMEM;
 703 }
 704
 705 static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net)
 706 {
 707         struct ctl_table *table;
 708
 709         table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
 710         unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
 711         if (!net_eq(net, &init_net))
 712                 kfree(table);
 713 }
 714
 715 static struct ctl_table_header *ip6_ctl_header;
 716
 717 static int ip6_frags_sysctl_register(void)
 718 {
 719         ip6_ctl_header = register_net_sysctl_rotable(net_ipv6_ctl_path,
 720                         ip6_frags_ctl_table);
 721         return ip6_ctl_header == NULL ? -ENOMEM : 0;
 722 }
 723
 724 static void ip6_frags_sysctl_unregister(void)
 725 {
 726         unregister_net_sysctl_table(ip6_ctl_header);
 727 }
 728 #else
 729 static inline int ip6_frags_ns_sysctl_register(struct net *net)
 730 {
 731         return 0;
 732 }
 733
 734 static inline void ip6_frags_ns_sysctl_unregister(struct net *net)
 735 {
 736 }
 737
 738 static inline int ip6_frags_sysctl_register(void)
 739 {
 740         return 0;
 741 }
 742
 743 static inline void ip6_frags_sysctl_unregister(void)
 744 {
 745 }
 746 #endif
 747
 748 static int __net_init ipv6_frags_init_net(struct net *net)
 749 {
 750         net->ipv6.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
 751         net->ipv6.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
 752         net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
 753
 754         inet_frags_init_net(&net->ipv6.frags);
 755
 756         return ip6_frags_ns_sysctl_register(net);
 757 }
 758
 759 static void __net_exit ipv6_frags_exit_net(struct net *net)
 760 {
 761         ip6_frags_ns_sysctl_unregister(net);
 762         inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
 763 }
 764
 765 static struct pernet_operations ip6_frags_ops = {
 766         .init = ipv6_frags_init_net,
 767         .exit = ipv6_frags_exit_net,
 768 };
 769
 770 int __init ipv6_frag_init(void)
 771 {
 772         int ret;
 773
 774         ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 775         if (ret)
 776                 goto out;
 777
 778         ret = ip6_frags_sysctl_register();
 779         if (ret)
 780                 goto err_sysctl;
 781
 782         ret = register_pernet_subsys(&ip6_frags_ops);
 783         if (ret)
 784                 goto err_pernet;
 785
 786         ip6_frags.hashfn = ip6_hashfn;
 787         ip6_frags.constructor = ip6_frag_init;
 788         ip6_frags.destructor = NULL;
 789         ip6_frags.skb_free = NULL;
 790         ip6_frags.qsize = sizeof(struct frag_queue);
 791         ip6_frags.match = ip6_frag_match;
 792         ip6_frags.frag_expire = ip6_frag_expire;
 793         ip6_frags.secret_interval = 10 * 60 * HZ;
 794         inet_frags_init(&ip6_frags);
 795 out:
 796         return ret;
 797
 798 err_pernet:
 799         ip6_frags_sysctl_unregister();
 800 err_sysctl:
 801         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 802         goto out;
 803 }
 804
 805 void ipv6_frag_exit(void)
 806 {
 807         inet_frags_fini(&ip6_frags);
 808         ip6_frags_sysctl_unregister();
 809         unregister_pernet_subsys(&ip6_frags_ops);
 810         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 811 }