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 #include <linux/slab.h>
  45 #include <linux/export.h>
  46
  47 #include <net/sock.h>
  48 #include <net/snmp.h>
  49
  50 #include <net/ipv6.h>
  51 #include <net/ip6_route.h>
  52 #include <net/protocol.h>
  53 #include <net/transp_v6.h>
  54 #include <net/rawv6.h>
  55 #include <net/ndisc.h>
  56 #include <net/addrconf.h>
  57 #include <net/inet_frag.h>
  58
  59 struct ip6frag_skb_cb
  60 {
  61         struct inet6_skb_parm   h;
  62         int                     offset;
  63 };
  64
  65 #define FRAG6_CB(skb)   ((struct ip6frag_skb_cb*)((skb)->cb))
  66
  67
  68 static struct inet_frags ip6_frags;
  69
  70 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
  71                           struct net_device *dev);
  72
  73 /*
  74  * callers should be careful not to use the hash value outside the ipfrag_lock
  75  * as doing so could race with ipfrag_hash_rnd being recalculated.
  76  */
  77 unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
  78                              const struct in6_addr *daddr, u32 rnd)
  79 {
  80         u32 c;
  81
  82         c = jhash_3words((__force u32)saddr->s6_addr32[0],
  83                          (__force u32)saddr->s6_addr32[1],
  84                          (__force u32)saddr->s6_addr32[2],
  85                          rnd);
  86
  87         c = jhash_3words((__force u32)saddr->s6_addr32[3],
  88                          (__force u32)daddr->s6_addr32[0],
  89                          (__force u32)daddr->s6_addr32[1],
  90                          c);
  91
  92         c =  jhash_3words((__force u32)daddr->s6_addr32[2],
  93                           (__force u32)daddr->s6_addr32[3],
  94                           (__force u32)id,
  95                           c);
  96
  97         return c & (INETFRAGS_HASHSZ - 1);
  98 }
  99 EXPORT_SYMBOL_GPL(inet6_hash_frag);
 100
 101 static unsigned int ip6_hashfn(struct inet_frag_queue *q)
 102 {
 103         struct frag_queue *fq;
 104
 105         fq = container_of(q, struct frag_queue, q);
 106         return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr, ip6_frags.rnd);
 107 }
 108
 109 bool ip6_frag_match(struct inet_frag_queue *q, void *a)
 110 {
 111         struct frag_queue *fq;
 112         struct ip6_create_arg *arg = a;
 113
 114         fq = container_of(q, struct frag_queue, q);
 115         return  fq->id == arg->id &&
 116                 fq->user == arg->user &&
 117                 ipv6_addr_equal(&fq->saddr, arg->src) &&
 118                 ipv6_addr_equal(&fq->daddr, arg->dst);
 119 }
 120 EXPORT_SYMBOL(ip6_frag_match);
 121
 122 void ip6_frag_init(struct inet_frag_queue *q, void *a)
 123 {
 124         struct frag_queue *fq = container_of(q, struct frag_queue, q);
 125         struct ip6_create_arg *arg = a;
 126
 127         fq->id = arg->id;
 128         fq->user = arg->user;
 129         fq->saddr = *arg->src;
 130         fq->daddr = *arg->dst;
 131 }
 132 EXPORT_SYMBOL(ip6_frag_init);
 133
 134 void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq,
 135                            struct inet_frags *frags)
 136 {
 137         struct net_device *dev = NULL;
 138
 139         spin_lock(&fq->q.lock);
 140
 141         if (fq->q.last_in & INET_FRAG_COMPLETE)
 142                 goto out;
 143
 144         inet_frag_kill(&fq->q, frags);
 145
 146         rcu_read_lock();
 147         dev = dev_get_by_index_rcu(net, fq->iif);
 148         if (!dev)
 149                 goto out_rcu_unlock;
 150
 151         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 152         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 153
 154         /* Don't send error if the first segment did not arrive. */
 155         if (!(fq->q.last_in & INET_FRAG_FIRST_IN) || !fq->q.fragments)
 156                 goto out_rcu_unlock;
 157
 158         /*
 159            But use as source device on which LAST ARRIVED
 160            segment was received. And do not use fq->dev
 161            pointer directly, device might already disappeared.
 162          */
 163         fq->q.fragments->dev = dev;
 164         icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
 165 out_rcu_unlock:
 166         rcu_read_unlock();
 167 out:
 168         spin_unlock(&fq->q.lock);
 169         inet_frag_put(&fq->q, frags);
 170 }
 171 EXPORT_SYMBOL(ip6_expire_frag_queue);
 172
 173 static void ip6_frag_expire(unsigned long data)
 174 {
 175         struct frag_queue *fq;
 176         struct net *net;
 177
 178         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 179         net = container_of(fq->q.net, struct net, ipv6.frags);
 180
 181         ip6_expire_frag_queue(net, fq, &ip6_frags);
 182 }
 183
 184 static __inline__ struct frag_queue *
 185 fq_find(struct net *net, __be32 id, const struct in6_addr *src, const struct in6_addr *dst)
 186 {
 187         struct inet_frag_queue *q;
 188         struct ip6_create_arg arg;
 189         unsigned int hash;
 190
 191         arg.id = id;
 192         arg.user = IP6_DEFRAG_LOCAL_DELIVER;
 193         arg.src = src;
 194         arg.dst = dst;
 195
 196         read_lock(&ip6_frags.lock);
 197         hash = inet6_hash_frag(id, src, dst, ip6_frags.rnd);
 198
 199         q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
 200         if (q == NULL)
 201                 return NULL;
 202
 203         return container_of(q, struct frag_queue, q);
 204 }
 205
 206 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 207                            struct frag_hdr *fhdr, int nhoff)
 208 {
 209         struct sk_buff *prev, *next;
 210         struct net_device *dev;
 211         int offset, end;
 212         struct net *net = dev_net(skb_dst(skb)->dev);
 213
 214         if (fq->q.last_in & INET_FRAG_COMPLETE)
 215                 goto err;
 216
 217         offset = ntohs(fhdr->frag_off) & ~0x7;
 218         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 219                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 220
 221         if ((unsigned int)end > IPV6_MAXPLEN) {
 222                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 223                                  IPSTATS_MIB_INHDRERRORS);
 224                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 225                                   ((u8 *)&fhdr->frag_off -
 226                                    skb_network_header(skb)));
 227                 return -1;
 228         }
 229
 230         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 231                 const unsigned char *nh = skb_network_header(skb);
 232                 skb->csum = csum_sub(skb->csum,
 233                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 234                                                   0));
 235         }
 236
 237         /* Is this the final fragment? */
 238         if (!(fhdr->frag_off & htons(IP6_MF))) {
 239                 /* If we already have some bits beyond end
 240                  * or have different end, the segment is corrupted.
 241                  */
 242                 if (end < fq->q.len ||
 243                     ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
 244                         goto err;
 245                 fq->q.last_in |= INET_FRAG_LAST_IN;
 246                 fq->q.len = end;
 247         } else {
 248                 /* Check if the fragment is rounded to 8 bytes.
 249                  * Required by the RFC.
 250                  */
 251                 if (end & 0x7) {
 252                         /* RFC2460 says always send parameter problem in
 253                          * this case. -DaveM
 254                          */
 255                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 256                                          IPSTATS_MIB_INHDRERRORS);
 257                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 258                                           offsetof(struct ipv6hdr, payload_len));
 259                         return -1;
 260                 }
 261                 if (end > fq->q.len) {
 262                         /* Some bits beyond end -> corruption. */
 263                         if (fq->q.last_in & INET_FRAG_LAST_IN)
 264                                 goto err;
 265                         fq->q.len = end;
 266                 }
 267         }
 268
 269         if (end == offset)
 270                 goto err;
 271
 272         /* Point into the IP datagram 'data' part. */
 273         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 274                 goto err;
 275
 276         if (pskb_trim_rcsum(skb, end - offset))
 277                 goto err;
 278
 279         /* Find out which fragments are in front and at the back of us
 280          * in the chain of fragments so far.  We must know where to put
 281          * this fragment, right?
 282          */
 283         prev = fq->q.fragments_tail;
 284         if (!prev || FRAG6_CB(prev)->offset < offset) {
 285                 next = NULL;
 286                 goto found;
 287         }
 288         prev = NULL;
 289         for(next = fq->q.fragments; next != NULL; next = next->next) {
 290                 if (FRAG6_CB(next)->offset >= offset)
 291                         break;  /* bingo! */
 292                 prev = next;
 293         }
 294
 295 found:
 296         /* RFC5722, Section 4, amended by Errata ID : 3089
 297          *                          When reassembling an IPv6 datagram, if
 298          *   one or more its constituent fragments is determined to be an
 299          *   overlapping fragment, the entire datagram (and any constituent
 300          *   fragments) MUST be silently discarded.
 301          */
 302
 303         /* Check for overlap with preceding fragment. */
 304         if (prev &&
 305             (FRAG6_CB(prev)->offset + prev->len) > offset)
 306                 goto discard_fq;
 307
 308         /* Look for overlap with succeeding segment. */
 309         if (next && FRAG6_CB(next)->offset < end)
 310                 goto discard_fq;
 311
 312         FRAG6_CB(skb)->offset = offset;
 313
 314         /* Insert this fragment in the chain of fragments. */
 315         skb->next = next;
 316         if (!next)
 317                 fq->q.fragments_tail = skb;
 318         if (prev)
 319                 prev->next = skb;
 320         else
 321                 fq->q.fragments = skb;
 322
 323         dev = skb->dev;
 324         if (dev) {
 325                 fq->iif = dev->ifindex;
 326                 skb->dev = NULL;
 327         }
 328         fq->q.stamp = skb->tstamp;
 329         fq->q.meat += skb->len;
 330         atomic_add(skb->truesize, &fq->q.net->mem);
 331
 332         /* The first fragment.
 333          * nhoffset is obtained from the first fragment, of course.
 334          */
 335         if (offset == 0) {
 336                 fq->nhoffset = nhoff;
 337                 fq->q.last_in |= INET_FRAG_FIRST_IN;
 338         }
 339
 340         if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 341             fq->q.meat == fq->q.len)
 342                 return ip6_frag_reasm(fq, prev, dev);
 343
 344         write_lock(&ip6_frags.lock);
 345         list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
 346         write_unlock(&ip6_frags.lock);
 347         return -1;
 348
 349 discard_fq:
 350         inet_frag_kill(&fq->q, &ip6_frags);
 351 err:
 352         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 353                       IPSTATS_MIB_REASMFAILS);
 354         kfree_skb(skb);
 355         return -1;
 356 }
 357
 358 /*
 359  *      Check if this packet is complete.
 360  *      Returns NULL on failure by any reason, and pointer
 361  *      to current nexthdr field in reassembled frame.
 362  *
 363  *      It is called with locked fq, and caller must check that
 364  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 365  *      the last and the first frames arrived and all the bits are here.
 366  */
 367 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 368                           struct net_device *dev)
 369 {
 370         struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
 371         struct sk_buff *fp, *head = fq->q.fragments;
 372         int    payload_len;
 373         unsigned int nhoff;
 374         int sum_truesize;
 375
 376         inet_frag_kill(&fq->q, &ip6_frags);
 377
 378         /* Make the one we just received the head. */
 379         if (prev) {
 380                 head = prev->next;
 381                 fp = skb_clone(head, GFP_ATOMIC);
 382
 383                 if (!fp)
 384                         goto out_oom;
 385
 386                 fp->next = head->next;
 387                 if (!fp->next)
 388                         fq->q.fragments_tail = fp;
 389                 prev->next = fp;
 390
 391                 skb_morph(head, fq->q.fragments);
 392                 head->next = fq->q.fragments->next;
 393
 394                 consume_skb(fq->q.fragments);
 395                 fq->q.fragments = head;
 396         }
 397
 398         WARN_ON(head == NULL);
 399         WARN_ON(FRAG6_CB(head)->offset != 0);
 400
 401         /* Unfragmented part is taken from the first segment. */
 402         payload_len = ((head->data - skb_network_header(head)) -
 403                        sizeof(struct ipv6hdr) + fq->q.len -
 404                        sizeof(struct frag_hdr));
 405         if (payload_len > IPV6_MAXPLEN)
 406                 goto out_oversize;
 407
 408         /* Head of list must not be cloned. */
 409         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 410                 goto out_oom;
 411
 412         /* If the first fragment is fragmented itself, we split
 413          * it to two chunks: the first with data and paged part
 414          * and the second, holding only fragments. */
 415         if (skb_has_frag_list(head)) {
 416                 struct sk_buff *clone;
 417                 int i, plen = 0;
 418
 419                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 420                         goto out_oom;
 421                 clone->next = head->next;
 422                 head->next = clone;
 423                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 424                 skb_frag_list_init(head);
 425                 for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
 426                         plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
 427                 clone->len = clone->data_len = head->data_len - plen;
 428                 head->data_len -= clone->len;
 429                 head->len -= clone->len;
 430                 clone->csum = 0;
 431                 clone->ip_summed = head->ip_summed;
 432                 atomic_add(clone->truesize, &fq->q.net->mem);
 433         }
 434
 435         /* We have to remove fragment header from datagram and to relocate
 436          * header in order to calculate ICV correctly. */
 437         nhoff = fq->nhoffset;
 438         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 439         memmove(head->head + sizeof(struct frag_hdr), head->head,
 440                 (head->data - head->head) - sizeof(struct frag_hdr));
 441         head->mac_header += sizeof(struct frag_hdr);
 442         head->network_header += sizeof(struct frag_hdr);
 443
 444         skb_reset_transport_header(head);
 445         skb_push(head, head->data - skb_network_header(head));
 446
 447         sum_truesize = head->truesize;
 448         for (fp = head->next; fp;) {
 449                 bool headstolen;
 450                 int delta;
 451                 struct sk_buff *next = fp->next;
 452
 453                 sum_truesize += fp->truesize;
 454                 if (head->ip_summed != fp->ip_summed)
 455                         head->ip_summed = CHECKSUM_NONE;
 456                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 457                         head->csum = csum_add(head->csum, fp->csum);
 458
 459                 if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
 460                         kfree_skb_partial(fp, headstolen);
 461                 } else {
 462                         if (!skb_shinfo(head)->frag_list)
 463                                 skb_shinfo(head)->frag_list = fp;
 464                         head->data_len += fp->len;
 465                         head->len += fp->len;
 466                         head->truesize += fp->truesize;
 467                 }
 468                 fp = next;
 469         }
 470         atomic_sub(sum_truesize, &fq->q.net->mem);
 471
 472         head->next = NULL;
 473         head->dev = dev;
 474         head->tstamp = fq->q.stamp;
 475         ipv6_hdr(head)->payload_len = htons(payload_len);
 476         IP6CB(head)->nhoff = nhoff;
 477
 478         /* Yes, and fold redundant checksum back. 8) */
 479         if (head->ip_summed == CHECKSUM_COMPLETE)
 480                 head->csum = csum_partial(skb_network_header(head),
 481                                           skb_network_header_len(head),
 482                                           head->csum);
 483
 484         rcu_read_lock();
 485         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 486         rcu_read_unlock();
 487         fq->q.fragments = NULL;
 488         fq->q.fragments_tail = NULL;
 489         return 1;
 490
 491 out_oversize:
 492         net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len);
 493         goto out_fail;
 494 out_oom:
 495         net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n");
 496 out_fail:
 497         rcu_read_lock();
 498         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 499         rcu_read_unlock();
 500         return -1;
 501 }
 502
 503 static int ipv6_frag_rcv(struct sk_buff *skb)
 504 {
 505         struct frag_hdr *fhdr;
 506         struct frag_queue *fq;
 507         const struct ipv6hdr *hdr = ipv6_hdr(skb);
 508         struct net *net = dev_net(skb_dst(skb)->dev);
 509         int evicted;
 510
 511         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
 512
 513         /* Jumbo payload inhibits frag. header */
 514         if (hdr->payload_len==0)
 515                 goto fail_hdr;
 516
 517         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 518                                  sizeof(struct frag_hdr))))
 519                 goto fail_hdr;
 520
 521         hdr = ipv6_hdr(skb);
 522         fhdr = (struct frag_hdr *)skb_transport_header(skb);
 523
 524         if (!(fhdr->frag_off & htons(0xFFF9))) {
 525                 /* It is not a fragmented frame */
 526                 skb->transport_header += sizeof(struct frag_hdr);
 527                 IP6_INC_STATS_BH(net,
 528                                  ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
 529
 530                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 531                 return 1;
 532         }
 533
 534         evicted = inet_frag_evictor(&net->ipv6.frags, &ip6_frags, false);
 535         if (evicted)
 536                 IP6_ADD_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 537                                  IPSTATS_MIB_REASMFAILS, evicted);
 538
 539         fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr);
 540         if (fq != NULL) {
 541                 int ret;
 542
 543                 spin_lock(&fq->q.lock);
 544
 545                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 546
 547                 spin_unlock(&fq->q.lock);
 548                 inet_frag_put(&fq->q, &ip6_frags);
 549                 return ret;
 550         }
 551
 552         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
 553         kfree_skb(skb);
 554         return -1;
 555
 556 fail_hdr:
 557         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
 558         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
 559         return -1;
 560 }
 561
 562 static const struct inet6_protocol frag_protocol =
 563 {
 564         .handler        =       ipv6_frag_rcv,
 565         .flags          =       INET6_PROTO_NOPOLICY,
 566 };
 567
 568 #ifdef CONFIG_SYSCTL
 569 static struct ctl_table ip6_frags_ns_ctl_table[] = {
 570         {
 571                 .procname       = "ip6frag_high_thresh",
 572                 .data           = &init_net.ipv6.frags.high_thresh,
 573                 .maxlen         = sizeof(int),
 574                 .mode           = 0644,
 575                 .proc_handler   = proc_dointvec
 576         },
 577         {
 578                 .procname       = "ip6frag_low_thresh",
 579                 .data           = &init_net.ipv6.frags.low_thresh,
 580                 .maxlen         = sizeof(int),
 581                 .mode           = 0644,
 582                 .proc_handler   = proc_dointvec
 583         },
 584         {
 585                 .procname       = "ip6frag_time",
 586                 .data           = &init_net.ipv6.frags.timeout,
 587                 .maxlen         = sizeof(int),
 588                 .mode           = 0644,
 589                 .proc_handler   = proc_dointvec_jiffies,
 590         },
 591         { }
 592 };
 593
 594 static struct ctl_table ip6_frags_ctl_table[] = {
 595         {
 596                 .procname       = "ip6frag_secret_interval",
 597                 .data           = &ip6_frags.secret_interval,
 598                 .maxlen         = sizeof(int),
 599                 .mode           = 0644,
 600                 .proc_handler   = proc_dointvec_jiffies,
 601         },
 602         { }
 603 };
 604
 605 static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
 606 {
 607         struct ctl_table *table;
 608         struct ctl_table_header *hdr;
 609
 610         table = ip6_frags_ns_ctl_table;
 611         if (!net_eq(net, &init_net)) {
 612                 table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
 613                 if (table == NULL)
 614                         goto err_alloc;
 615
 616                 table[0].data = &net->ipv6.frags.high_thresh;
 617                 table[1].data = &net->ipv6.frags.low_thresh;
 618                 table[2].data = &net->ipv6.frags.timeout;
 619
 620                 /* Don't export sysctls to unprivileged users */
 621                 if (net->user_ns != &init_user_ns)
 622                         table[0].procname = NULL;
 623         }
 624
 625         hdr = register_net_sysctl(net, "net/ipv6", table);
 626         if (hdr == NULL)
 627                 goto err_reg;
 628
 629         net->ipv6.sysctl.frags_hdr = hdr;
 630         return 0;
 631
 632 err_reg:
 633         if (!net_eq(net, &init_net))
 634                 kfree(table);
 635 err_alloc:
 636         return -ENOMEM;
 637 }
 638
 639 static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net)
 640 {
 641         struct ctl_table *table;
 642
 643         table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
 644         unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
 645         if (!net_eq(net, &init_net))
 646                 kfree(table);
 647 }
 648
 649 static struct ctl_table_header *ip6_ctl_header;
 650
 651 static int ip6_frags_sysctl_register(void)
 652 {
 653         ip6_ctl_header = register_net_sysctl(&init_net, "net/ipv6",
 654                         ip6_frags_ctl_table);
 655         return ip6_ctl_header == NULL ? -ENOMEM : 0;
 656 }
 657
 658 static void ip6_frags_sysctl_unregister(void)
 659 {
 660         unregister_net_sysctl_table(ip6_ctl_header);
 661 }
 662 #else
 663 static inline int ip6_frags_ns_sysctl_register(struct net *net)
 664 {
 665         return 0;
 666 }
 667
 668 static inline void ip6_frags_ns_sysctl_unregister(struct net *net)
 669 {
 670 }
 671
 672 static inline int ip6_frags_sysctl_register(void)
 673 {
 674         return 0;
 675 }
 676
 677 static inline void ip6_frags_sysctl_unregister(void)
 678 {
 679 }
 680 #endif
 681
 682 static int __net_init ipv6_frags_init_net(struct net *net)
 683 {
 684         net->ipv6.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
 685         net->ipv6.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
 686         net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
 687
 688         inet_frags_init_net(&net->ipv6.frags);
 689
 690         return ip6_frags_ns_sysctl_register(net);
 691 }
 692
 693 static void __net_exit ipv6_frags_exit_net(struct net *net)
 694 {
 695         ip6_frags_ns_sysctl_unregister(net);
 696         inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
 697 }
 698
 699 static struct pernet_operations ip6_frags_ops = {
 700         .init = ipv6_frags_init_net,
 701         .exit = ipv6_frags_exit_net,
 702 };
 703
 704 int __init ipv6_frag_init(void)
 705 {
 706         int ret;
 707
 708         ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 709         if (ret)
 710                 goto out;
 711
 712         ret = ip6_frags_sysctl_register();
 713         if (ret)
 714                 goto err_sysctl;
 715
 716         ret = register_pernet_subsys(&ip6_frags_ops);
 717         if (ret)
 718                 goto err_pernet;
 719
 720         ip6_frags.hashfn = ip6_hashfn;
 721         ip6_frags.constructor = ip6_frag_init;
 722         ip6_frags.destructor = NULL;
 723         ip6_frags.skb_free = NULL;
 724         ip6_frags.qsize = sizeof(struct frag_queue);
 725         ip6_frags.match = ip6_frag_match;
 726         ip6_frags.frag_expire = ip6_frag_expire;
 727         ip6_frags.secret_interval = 10 * 60 * HZ;
 728         inet_frags_init(&ip6_frags);
 729 out:
 730         return ret;
 731
 732 err_pernet:
 733         ip6_frags_sysctl_unregister();
 734 err_sysctl:
 735         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 736         goto out;
 737 }
 738
 739 void ipv6_frag_exit(void)
 740 {
 741         inet_frags_fini(&ip6_frags);
 742         ip6_frags_sysctl_unregister();
 743         unregister_pernet_subsys(&ip6_frags_ops);
 744         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 745 }