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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         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(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(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 217         IP6_INC_STATS_BH(__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(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
 271         if (fq->q.last_in & INET_FRAG_COMPLETE)
 272                 goto err;
 273
 274         offset = ntohs(fhdr->frag_off) & ~0x7;
 275         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 276                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 277
 278         if ((unsigned int)end > IPV6_MAXPLEN) {
 279                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 280                                  IPSTATS_MIB_INHDRERRORS);
 281                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 282                                   ((u8 *)&fhdr->frag_off -
 283                                    skb_network_header(skb)));
 284                 return -1;
 285         }
 286
 287         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 288                 const unsigned char *nh = skb_network_header(skb);
 289                 skb->csum = csum_sub(skb->csum,
 290                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 291                                                   0));
 292         }
 293
 294         /* Is this the final fragment? */
 295         if (!(fhdr->frag_off & htons(IP6_MF))) {
 296                 /* If we already have some bits beyond end
 297                  * or have different end, the segment is corrupted.
 298                  */
 299                 if (end < fq->q.len ||
 300                     ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
 301                         goto err;
 302                 fq->q.last_in |= INET_FRAG_LAST_IN;
 303                 fq->q.len = end;
 304         } else {
 305                 /* Check if the fragment is rounded to 8 bytes.
 306                  * Required by the RFC.
 307                  */
 308                 if (end & 0x7) {
 309                         /* RFC2460 says always send parameter problem in
 310                          * this case. -DaveM
 311                          */
 312                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 313                                          IPSTATS_MIB_INHDRERRORS);
 314                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 315                                           offsetof(struct ipv6hdr, payload_len));
 316                         return -1;
 317                 }
 318                 if (end > fq->q.len) {
 319                         /* Some bits beyond end -> corruption. */
 320                         if (fq->q.last_in & INET_FRAG_LAST_IN)
 321                                 goto err;
 322                         fq->q.len = end;
 323                 }
 324         }
 325
 326         if (end == offset)
 327                 goto err;
 328
 329         /* Point into the IP datagram 'data' part. */
 330         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 331                 goto err;
 332
 333         if (pskb_trim_rcsum(skb, end - offset))
 334                 goto err;
 335
 336         /* Find out which fragments are in front and at the back of us
 337          * in the chain of fragments so far.  We must know where to put
 338          * this fragment, right?
 339          */
 340         prev = NULL;
 341         for(next = fq->q.fragments; next != NULL; next = next->next) {
 342                 if (FRAG6_CB(next)->offset >= offset)
 343                         break;  /* bingo! */
 344                 prev = next;
 345         }
 346
 347         /* We found where to put this one.  Check for overlap with
 348          * preceding fragment, and, if needed, align things so that
 349          * any overlaps are eliminated.
 350          */
 351         if (prev) {
 352                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
 353
 354                 if (i > 0) {
 355                         offset += i;
 356                         if (end <= offset)
 357                                 goto err;
 358                         if (!pskb_pull(skb, i))
 359                                 goto err;
 360                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 361                                 skb->ip_summed = CHECKSUM_NONE;
 362                 }
 363         }
 364
 365         /* Look for overlap with succeeding segments.
 366          * If we can merge fragments, do it.
 367          */
 368         while (next && FRAG6_CB(next)->offset < end) {
 369                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
 370
 371                 if (i < next->len) {
 372                         /* Eat head of the next overlapped fragment
 373                          * and leave the loop. The next ones cannot overlap.
 374                          */
 375                         if (!pskb_pull(next, i))
 376                                 goto err;
 377                         FRAG6_CB(next)->offset += i;    /* next fragment */
 378                         fq->q.meat -= i;
 379                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 380                                 next->ip_summed = CHECKSUM_NONE;
 381                         break;
 382                 } else {
 383                         struct sk_buff *free_it = next;
 384
 385                         /* Old fragment is completely overridden with
 386                          * new one drop it.
 387                          */
 388                         next = next->next;
 389
 390                         if (prev)
 391                                 prev->next = next;
 392                         else
 393                                 fq->q.fragments = next;
 394
 395                         fq->q.meat -= free_it->len;
 396                         frag_kfree_skb(fq->q.net, free_it, NULL);
 397                 }
 398         }
 399
 400         FRAG6_CB(skb)->offset = offset;
 401
 402         /* Insert this fragment in the chain of fragments. */
 403         skb->next = next;
 404         if (prev)
 405                 prev->next = skb;
 406         else
 407                 fq->q.fragments = skb;
 408
 409         dev = skb->dev;
 410         if (dev) {
 411                 fq->iif = dev->ifindex;
 412                 skb->dev = NULL;
 413         }
 414         fq->q.stamp = skb->tstamp;
 415         fq->q.meat += skb->len;
 416         atomic_add(skb->truesize, &fq->q.net->mem);
 417
 418         /* The first fragment.
 419          * nhoffset is obtained from the first fragment, of course.
 420          */
 421         if (offset == 0) {
 422                 fq->nhoffset = nhoff;
 423                 fq->q.last_in |= INET_FRAG_FIRST_IN;
 424         }
 425
 426         if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 427             fq->q.meat == fq->q.len)
 428                 return ip6_frag_reasm(fq, prev, dev);
 429
 430         write_lock(&ip6_frags.lock);
 431         list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
 432         write_unlock(&ip6_frags.lock);
 433         return -1;
 434
 435 err:
 436         IP6_INC_STATS(dev_net(skb->dst->dev), ip6_dst_idev(skb->dst),
 437                       IPSTATS_MIB_REASMFAILS);
 438         kfree_skb(skb);
 439         return -1;
 440 }
 441
 442 /*
 443  *      Check if this packet is complete.
 444  *      Returns NULL on failure by any reason, and pointer
 445  *      to current nexthdr field in reassembled frame.
 446  *
 447  *      It is called with locked fq, and caller must check that
 448  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 449  *      the last and the first frames arrived and all the bits are here.
 450  */
 451 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 452                           struct net_device *dev)
 453 {
 454         struct sk_buff *fp, *head = fq->q.fragments;
 455         int    payload_len;
 456         unsigned int nhoff;
 457
 458         fq_kill(fq);
 459
 460         /* Make the one we just received the head. */
 461         if (prev) {
 462                 head = prev->next;
 463                 fp = skb_clone(head, GFP_ATOMIC);
 464
 465                 if (!fp)
 466                         goto out_oom;
 467
 468                 fp->next = head->next;
 469                 prev->next = fp;
 470
 471                 skb_morph(head, fq->q.fragments);
 472                 head->next = fq->q.fragments->next;
 473
 474                 kfree_skb(fq->q.fragments);
 475                 fq->q.fragments = head;
 476         }
 477
 478         WARN_ON(head == NULL);
 479         WARN_ON(FRAG6_CB(head)->offset != 0);
 480
 481         /* Unfragmented part is taken from the first segment. */
 482         payload_len = ((head->data - skb_network_header(head)) -
 483                        sizeof(struct ipv6hdr) + fq->q.len -
 484                        sizeof(struct frag_hdr));
 485         if (payload_len > IPV6_MAXPLEN)
 486                 goto out_oversize;
 487
 488         /* Head of list must not be cloned. */
 489         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 490                 goto out_oom;
 491
 492         /* If the first fragment is fragmented itself, we split
 493          * it to two chunks: the first with data and paged part
 494          * and the second, holding only fragments. */
 495         if (skb_shinfo(head)->frag_list) {
 496                 struct sk_buff *clone;
 497                 int i, plen = 0;
 498
 499                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 500                         goto out_oom;
 501                 clone->next = head->next;
 502                 head->next = clone;
 503                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 504                 skb_shinfo(head)->frag_list = NULL;
 505                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 506                         plen += skb_shinfo(head)->frags[i].size;
 507                 clone->len = clone->data_len = head->data_len - plen;
 508                 head->data_len -= clone->len;
 509                 head->len -= clone->len;
 510                 clone->csum = 0;
 511                 clone->ip_summed = head->ip_summed;
 512                 atomic_add(clone->truesize, &fq->q.net->mem);
 513         }
 514
 515         /* We have to remove fragment header from datagram and to relocate
 516          * header in order to calculate ICV correctly. */
 517         nhoff = fq->nhoffset;
 518         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 519         memmove(head->head + sizeof(struct frag_hdr), head->head,
 520                 (head->data - head->head) - sizeof(struct frag_hdr));
 521         head->mac_header += sizeof(struct frag_hdr);
 522         head->network_header += sizeof(struct frag_hdr);
 523
 524         skb_shinfo(head)->frag_list = head->next;
 525         skb_reset_transport_header(head);
 526         skb_push(head, head->data - skb_network_header(head));
 527         atomic_sub(head->truesize, &fq->q.net->mem);
 528
 529         for (fp=head->next; fp; fp = fp->next) {
 530                 head->data_len += fp->len;
 531                 head->len += fp->len;
 532                 if (head->ip_summed != fp->ip_summed)
 533                         head->ip_summed = CHECKSUM_NONE;
 534                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 535                         head->csum = csum_add(head->csum, fp->csum);
 536                 head->truesize += fp->truesize;
 537                 atomic_sub(fp->truesize, &fq->q.net->mem);
 538         }
 539
 540         head->next = NULL;
 541         head->dev = dev;
 542         head->tstamp = fq->q.stamp;
 543         ipv6_hdr(head)->payload_len = htons(payload_len);
 544         IP6CB(head)->nhoff = nhoff;
 545
 546         /* Yes, and fold redundant checksum back. 8) */
 547         if (head->ip_summed == CHECKSUM_COMPLETE)
 548                 head->csum = csum_partial(skb_network_header(head),
 549                                           skb_network_header_len(head),
 550                                           head->csum);
 551
 552         rcu_read_lock();
 553         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 554         rcu_read_unlock();
 555         fq->q.fragments = NULL;
 556         return 1;
 557
 558 out_oversize:
 559         if (net_ratelimit())
 560                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
 561         goto out_fail;
 562 out_oom:
 563         if (net_ratelimit())
 564                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
 565 out_fail:
 566         rcu_read_lock();
 567         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 568         rcu_read_unlock();
 569         return -1;
 570 }
 571
 572 static int ipv6_frag_rcv(struct sk_buff *skb)
 573 {
 574         struct frag_hdr *fhdr;
 575         struct frag_queue *fq;
 576         struct ipv6hdr *hdr = ipv6_hdr(skb);
 577         struct net *net = dev_net(skb->dst->dev);
 578
 579         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS);
 580
 581         /* Jumbo payload inhibits frag. header */
 582         if (hdr->payload_len==0)
 583                 goto fail_hdr;
 584
 585         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 586                                  sizeof(struct frag_hdr))))
 587                 goto fail_hdr;
 588
 589         hdr = ipv6_hdr(skb);
 590         fhdr = (struct frag_hdr *)skb_transport_header(skb);
 591
 592         if (!(fhdr->frag_off & htons(0xFFF9))) {
 593                 /* It is not a fragmented frame */
 594                 skb->transport_header += sizeof(struct frag_hdr);
 595                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS);
 596
 597                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 598                 return 1;
 599         }
 600
 601         if (atomic_read(&net->ipv6.frags.mem) > net->ipv6.frags.high_thresh)
 602                 ip6_evictor(net, ip6_dst_idev(skb->dst));
 603
 604         if ((fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
 605                           ip6_dst_idev(skb->dst))) != NULL) {
 606                 int ret;
 607
 608                 spin_lock(&fq->q.lock);
 609
 610                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 611
 612                 spin_unlock(&fq->q.lock);
 613                 fq_put(fq);
 614                 return ret;
 615         }
 616
 617         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 618         kfree_skb(skb);
 619         return -1;
 620
 621 fail_hdr:
 622         IP6_INC_STATS(net, ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 623         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
 624         return -1;
 625 }
 626
 627 static struct inet6_protocol frag_protocol =
 628 {
 629         .handler        =       ipv6_frag_rcv,
 630         .flags          =       INET6_PROTO_NOPOLICY,
 631 };
 632
 633 #ifdef CONFIG_SYSCTL
 634 static struct ctl_table ip6_frags_ns_ctl_table[] = {
 635         {
 636                 .ctl_name       = NET_IPV6_IP6FRAG_HIGH_THRESH,
 637                 .procname       = "ip6frag_high_thresh",
 638                 .data           = &init_net.ipv6.frags.high_thresh,
 639                 .maxlen         = sizeof(int),
 640                 .mode           = 0644,
 641                 .proc_handler   = &proc_dointvec
 642         },
 643         {
 644                 .ctl_name       = NET_IPV6_IP6FRAG_LOW_THRESH,
 645                 .procname       = "ip6frag_low_thresh",
 646                 .data           = &init_net.ipv6.frags.low_thresh,
 647                 .maxlen         = sizeof(int),
 648                 .mode           = 0644,
 649                 .proc_handler   = &proc_dointvec
 650         },
 651         {
 652                 .ctl_name       = NET_IPV6_IP6FRAG_TIME,
 653                 .procname       = "ip6frag_time",
 654                 .data           = &init_net.ipv6.frags.timeout,
 655                 .maxlen         = sizeof(int),
 656                 .mode           = 0644,
 657                 .proc_handler   = &proc_dointvec_jiffies,
 658                 .strategy       = &sysctl_jiffies,
 659         },
 660         { }
 661 };
 662
 663 static struct ctl_table ip6_frags_ctl_table[] = {
 664         {
 665                 .ctl_name       = NET_IPV6_IP6FRAG_SECRET_INTERVAL,
 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                 .strategy       = &sysctl_jiffies
 672         },
 673         { }
 674 };
 675
 676 static int ip6_frags_ns_sysctl_register(struct net *net)
 677 {
 678         struct ctl_table *table;
 679         struct ctl_table_header *hdr;
 680
 681         table = ip6_frags_ns_ctl_table;
 682         if (net != &init_net) {
 683                 table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
 684                 if (table == NULL)
 685                         goto err_alloc;
 686
 687                 table[0].data = &net->ipv6.frags.high_thresh;
 688                 table[1].data = &net->ipv6.frags.low_thresh;
 689                 table[2].data = &net->ipv6.frags.timeout;
 690         }
 691
 692         hdr = register_net_sysctl_table(net, net_ipv6_ctl_path, table);
 693         if (hdr == NULL)
 694                 goto err_reg;
 695
 696         net->ipv6.sysctl.frags_hdr = hdr;
 697         return 0;
 698
 699 err_reg:
 700         if (net != &init_net)
 701                 kfree(table);
 702 err_alloc:
 703         return -ENOMEM;
 704 }
 705
 706 static void ip6_frags_ns_sysctl_unregister(struct net *net)
 707 {
 708         struct ctl_table *table;
 709
 710         table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
 711         unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
 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 ipv6_frags_init_net(struct net *net)
 749 {
 750         net->ipv6.frags.high_thresh = 256 * 1024;
 751         net->ipv6.frags.low_thresh = 192 * 1024;
 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 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 }