net/ipv6/netfilter/nf_conntrack_reasm.c

   1 /*
   2  * IPv6 fragment reassembly for connection tracking
   3  *
   4  * Copyright (C)2004 USAGI/WIDE Project
   5  *
   6  * Author:
   7  *      Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
   8  *
   9  * Based on: net/ipv6/reassembly.c
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version
  14  * 2 of the License, or (at your option) any later version.
  15  */
  16
  17 #define pr_fmt(fmt) "IPv6-nf: " fmt
  18
  19 #include <linux/errno.h>
  20 #include <linux/types.h>
  21 #include <linux/string.h>
  22 #include <linux/socket.h>
  23 #include <linux/sockios.h>
  24 #include <linux/jiffies.h>
  25 #include <linux/net.h>
  26 #include <linux/list.h>
  27 #include <linux/netdevice.h>
  28 #include <linux/in6.h>
  29 #include <linux/ipv6.h>
  30 #include <linux/icmpv6.h>
  31 #include <linux/random.h>
  32 #include <linux/slab.h>
  33
  34 #include <net/sock.h>
  35 #include <net/snmp.h>
  36 #include <net/inet_frag.h>
  37
  38 #include <net/ipv6.h>
  39 #include <net/protocol.h>
  40 #include <net/transp_v6.h>
  41 #include <net/rawv6.h>
  42 #include <net/ndisc.h>
  43 #include <net/addrconf.h>
  44 #include <net/inet_ecn.h>
  45 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  46 #include <linux/sysctl.h>
  47 #include <linux/netfilter.h>
  48 #include <linux/netfilter_ipv6.h>
  49 #include <linux/kernel.h>
  50 #include <linux/module.h>
  51 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
  52
  53
  54 struct nf_ct_frag6_skb_cb
  55 {
  56         struct inet6_skb_parm   h;
  57         int                     offset;
  58         struct sk_buff          *orig;
  59 };
  60
  61 #define NFCT_FRAG6_CB(skb)      ((struct nf_ct_frag6_skb_cb*)((skb)->cb))
  62
  63 static struct inet_frags nf_frags;
  64
  65 #ifdef CONFIG_SYSCTL
  66 static struct ctl_table nf_ct_frag6_sysctl_table[] = {
  67         {
  68                 .procname       = "nf_conntrack_frag6_timeout",
  69                 .data           = &init_net.nf_frag.frags.timeout,
  70                 .maxlen         = sizeof(unsigned int),
  71                 .mode           = 0644,
  72                 .proc_handler   = proc_dointvec_jiffies,
  73         },
  74         {
  75                 .procname       = "nf_conntrack_frag6_low_thresh",
  76                 .data           = &init_net.nf_frag.frags.low_thresh,
  77                 .maxlen         = sizeof(unsigned int),
  78                 .mode           = 0644,
  79                 .proc_handler   = proc_dointvec,
  80         },
  81         {
  82                 .procname       = "nf_conntrack_frag6_high_thresh",
  83                 .data           = &init_net.nf_frag.frags.high_thresh,
  84                 .maxlen         = sizeof(unsigned int),
  85                 .mode           = 0644,
  86                 .proc_handler   = proc_dointvec,
  87         },
  88         { }
  89 };
  90
  91 static int nf_ct_frag6_sysctl_register(struct net *net)
  92 {
  93         struct ctl_table *table;
  94         struct ctl_table_header *hdr;
  95
  96         table = nf_ct_frag6_sysctl_table;
  97         if (!net_eq(net, &init_net)) {
  98                 table = kmemdup(table, sizeof(nf_ct_frag6_sysctl_table),
  99                                 GFP_KERNEL);
 100                 if (table == NULL)
 101                         goto err_alloc;
 102
 103                 table[0].data = &net->nf_frag.frags.timeout;
 104                 table[1].data = &net->nf_frag.frags.low_thresh;
 105                 table[2].data = &net->nf_frag.frags.high_thresh;
 106         }
 107
 108         hdr = register_net_sysctl(net, "net/netfilter", table);
 109         if (hdr == NULL)
 110                 goto err_reg;
 111
 112         net->nf_frag.sysctl.frags_hdr = hdr;
 113         return 0;
 114
 115 err_reg:
 116         if (!net_eq(net, &init_net))
 117                 kfree(table);
 118 err_alloc:
 119         return -ENOMEM;
 120 }
 121
 122 static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
 123 {
 124         struct ctl_table *table;
 125
 126         table = net->nf_frag.sysctl.frags_hdr->ctl_table_arg;
 127         unregister_net_sysctl_table(net->nf_frag.sysctl.frags_hdr);
 128         if (!net_eq(net, &init_net))
 129                 kfree(table);
 130 }
 131
 132 #else
 133 static int nf_ct_frag6_sysctl_register(struct net *net)
 134 {
 135         return 0;
 136 }
 137 static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
 138 {
 139 }
 140 #endif
 141
 142 static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
 143 {
 144         return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
 145 }
 146
 147 static unsigned int nf_hash_frag(__be32 id, const struct in6_addr *saddr,
 148                                  const struct in6_addr *daddr)
 149 {
 150         net_get_random_once(&nf_frags.rnd, sizeof(nf_frags.rnd));
 151         return jhash_3words(ipv6_addr_hash(saddr), ipv6_addr_hash(daddr),
 152                             (__force u32)id, nf_frags.rnd);
 153 }
 154
 155
 156 static unsigned int nf_hashfn(const struct inet_frag_queue *q)
 157 {
 158         const struct frag_queue *nq;
 159
 160         nq = container_of(q, struct frag_queue, q);
 161         return nf_hash_frag(nq->id, &nq->saddr, &nq->daddr);
 162 }
 163
 164 static void nf_skb_free(struct sk_buff *skb)
 165 {
 166         if (NFCT_FRAG6_CB(skb)->orig)
 167                 kfree_skb(NFCT_FRAG6_CB(skb)->orig);
 168 }
 169
 170 static void nf_ct_frag6_expire(unsigned long data)
 171 {
 172         struct frag_queue *fq;
 173         struct net *net;
 174
 175         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 176         net = container_of(fq->q.net, struct net, nf_frag.frags);
 177
 178         ip6_expire_frag_queue(net, fq, &nf_frags);
 179 }
 180
 181 /* Creation primitives. */
 182 static inline struct frag_queue *fq_find(struct net *net, __be32 id,
 183                                          u32 user, struct in6_addr *src,
 184                                          struct in6_addr *dst, u8 ecn)
 185 {
 186         struct inet_frag_queue *q;
 187         struct ip6_create_arg arg;
 188         unsigned int hash;
 189
 190         arg.id = id;
 191         arg.user = user;
 192         arg.src = src;
 193         arg.dst = dst;
 194         arg.ecn = ecn;
 195
 196         read_lock_bh(&nf_frags.lock);
 197         hash = nf_hash_frag(id, src, dst);
 198
 199         q = inet_frag_find(&net->nf_frag.frags, &nf_frags, &arg, hash);
 200         local_bh_enable();
 201         if (IS_ERR_OR_NULL(q)) {
 202                 inet_frag_maybe_warn_overflow(q, pr_fmt());
 203                 return NULL;
 204         }
 205         return container_of(q, struct frag_queue, q);
 206 }
 207
 208
 209 static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb,
 210                              const struct frag_hdr *fhdr, int nhoff)
 211 {
 212         struct sk_buff *prev, *next;
 213         unsigned int payload_len;
 214         int offset, end;
 215         u8 ecn;
 216
 217         if (fq->q.last_in & INET_FRAG_COMPLETE) {
 218                 pr_debug("Already completed\n");
 219                 goto err;
 220         }
 221
 222         payload_len = ntohs(ipv6_hdr(skb)->payload_len);
 223
 224         offset = ntohs(fhdr->frag_off) & ~0x7;
 225         end = offset + (payload_len -
 226                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 227
 228         if ((unsigned int)end > IPV6_MAXPLEN) {
 229                 pr_debug("offset is too large.\n");
 230                 return -1;
 231         }
 232
 233         ecn = ip6_frag_ecn(ipv6_hdr(skb));
 234
 235         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 236                 const unsigned char *nh = skb_network_header(skb);
 237                 skb->csum = csum_sub(skb->csum,
 238                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 239                                                   0));
 240         }
 241
 242         /* Is this the final fragment? */
 243         if (!(fhdr->frag_off & htons(IP6_MF))) {
 244                 /* If we already have some bits beyond end
 245                  * or have different end, the segment is corrupted.
 246                  */
 247                 if (end < fq->q.len ||
 248                     ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len)) {
 249                         pr_debug("already received last fragment\n");
 250                         goto err;
 251                 }
 252                 fq->q.last_in |= INET_FRAG_LAST_IN;
 253                 fq->q.len = end;
 254         } else {
 255                 /* Check if the fragment is rounded to 8 bytes.
 256                  * Required by the RFC.
 257                  */
 258                 if (end & 0x7) {
 259                         /* RFC2460 says always send parameter problem in
 260                          * this case. -DaveM
 261                          */
 262                         pr_debug("end of fragment not rounded to 8 bytes.\n");
 263                         return -1;
 264                 }
 265                 if (end > fq->q.len) {
 266                         /* Some bits beyond end -> corruption. */
 267                         if (fq->q.last_in & INET_FRAG_LAST_IN) {
 268                                 pr_debug("last packet already reached.\n");
 269                                 goto err;
 270                         }
 271                         fq->q.len = end;
 272                 }
 273         }
 274
 275         if (end == offset)
 276                 goto err;
 277
 278         /* Point into the IP datagram 'data' part. */
 279         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) {
 280                 pr_debug("queue: message is too short.\n");
 281                 goto err;
 282         }
 283         if (pskb_trim_rcsum(skb, end - offset)) {
 284                 pr_debug("Can't trim\n");
 285                 goto err;
 286         }
 287
 288         /* Find out which fragments are in front and at the back of us
 289          * in the chain of fragments so far.  We must know where to put
 290          * this fragment, right?
 291          */
 292         prev = fq->q.fragments_tail;
 293         if (!prev || NFCT_FRAG6_CB(prev)->offset < offset) {
 294                 next = NULL;
 295                 goto found;
 296         }
 297         prev = NULL;
 298         for (next = fq->q.fragments; next != NULL; next = next->next) {
 299                 if (NFCT_FRAG6_CB(next)->offset >= offset)
 300                         break;  /* bingo! */
 301                 prev = next;
 302         }
 303
 304 found:
 305         /* RFC5722, Section 4:
 306          *                                  When reassembling an IPv6 datagram, if
 307          *   one or more its constituent fragments is determined to be an
 308          *   overlapping fragment, the entire datagram (and any constituent
 309          *   fragments, including those not yet received) MUST be silently
 310          *   discarded.
 311          */
 312
 313         /* Check for overlap with preceding fragment. */
 314         if (prev &&
 315             (NFCT_FRAG6_CB(prev)->offset + prev->len) > offset)
 316                 goto discard_fq;
 317
 318         /* Look for overlap with succeeding segment. */
 319         if (next && NFCT_FRAG6_CB(next)->offset < end)
 320                 goto discard_fq;
 321
 322         NFCT_FRAG6_CB(skb)->offset = offset;
 323
 324         /* Insert this fragment in the chain of fragments. */
 325         skb->next = next;
 326         if (!next)
 327                 fq->q.fragments_tail = skb;
 328         if (prev)
 329                 prev->next = skb;
 330         else
 331                 fq->q.fragments = skb;
 332
 333         if (skb->dev) {
 334                 fq->iif = skb->dev->ifindex;
 335                 skb->dev = NULL;
 336         }
 337         fq->q.stamp = skb->tstamp;
 338         fq->q.meat += skb->len;
 339         fq->ecn |= ecn;
 340         if (payload_len > fq->q.max_size)
 341                 fq->q.max_size = payload_len;
 342         add_frag_mem_limit(&fq->q, skb->truesize);
 343
 344         /* The first fragment.
 345          * nhoffset is obtained from the first fragment, of course.
 346          */
 347         if (offset == 0) {
 348                 fq->nhoffset = nhoff;
 349                 fq->q.last_in |= INET_FRAG_FIRST_IN;
 350         }
 351
 352         return 0;
 353
 354 discard_fq:
 355         inet_frag_kill(&fq->q, &nf_frags);
 356 err:
 357         return -1;
 358 }
 359
 360 /*
 361  *      Check if this packet is complete.
 362  *      Returns NULL on failure by any reason, and pointer
 363  *      to current nexthdr field in reassembled frame.
 364  *
 365  *      It is called with locked fq, and caller must check that
 366  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 367  *      the last and the first frames arrived and all the bits are here.
 368  */
 369 static struct sk_buff *
 370 nf_ct_frag6_reasm(struct frag_queue *fq, struct net_device *dev)
 371 {
 372         struct sk_buff *fp, *op, *head = fq->q.fragments;
 373         int    payload_len;
 374         u8 ecn;
 375
 376         inet_frag_kill(&fq->q, &nf_frags);
 377
 378         WARN_ON(head == NULL);
 379         WARN_ON(NFCT_FRAG6_CB(head)->offset != 0);
 380
 381         ecn = ip_frag_ecn_table[fq->ecn];
 382         if (unlikely(ecn == 0xff))
 383                 goto out_fail;
 384
 385         /* Unfragmented part is taken from the first segment. */
 386         payload_len = ((head->data - skb_network_header(head)) -
 387                        sizeof(struct ipv6hdr) + fq->q.len -
 388                        sizeof(struct frag_hdr));
 389         if (payload_len > IPV6_MAXPLEN) {
 390                 pr_debug("payload len is too large.\n");
 391                 goto out_oversize;
 392         }
 393
 394         /* Head of list must not be cloned. */
 395         if (skb_unclone(head, GFP_ATOMIC)) {
 396                 pr_debug("skb is cloned but can't expand head");
 397                 goto out_oom;
 398         }
 399
 400         /* If the first fragment is fragmented itself, we split
 401          * it to two chunks: the first with data and paged part
 402          * and the second, holding only fragments. */
 403         if (skb_has_frag_list(head)) {
 404                 struct sk_buff *clone;
 405                 int i, plen = 0;
 406
 407                 clone = alloc_skb(0, GFP_ATOMIC);
 408                 if (clone == NULL)
 409                         goto out_oom;
 410
 411                 clone->next = head->next;
 412                 head->next = clone;
 413                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 414                 skb_frag_list_init(head);
 415                 for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
 416                         plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
 417                 clone->len = clone->data_len = head->data_len - plen;
 418                 head->data_len -= clone->len;
 419                 head->len -= clone->len;
 420                 clone->csum = 0;
 421                 clone->ip_summed = head->ip_summed;
 422
 423                 NFCT_FRAG6_CB(clone)->orig = NULL;
 424                 add_frag_mem_limit(&fq->q, clone->truesize);
 425         }
 426
 427         /* We have to remove fragment header from datagram and to relocate
 428          * header in order to calculate ICV correctly. */
 429         skb_network_header(head)[fq->nhoffset] = skb_transport_header(head)[0];
 430         memmove(head->head + sizeof(struct frag_hdr), head->head,
 431                 (head->data - head->head) - sizeof(struct frag_hdr));
 432         head->mac_header += sizeof(struct frag_hdr);
 433         head->network_header += sizeof(struct frag_hdr);
 434
 435         skb_shinfo(head)->frag_list = head->next;
 436         skb_reset_transport_header(head);
 437         skb_push(head, head->data - skb_network_header(head));
 438
 439         for (fp=head->next; fp; fp = fp->next) {
 440                 head->data_len += fp->len;
 441                 head->len += fp->len;
 442                 if (head->ip_summed != fp->ip_summed)
 443                         head->ip_summed = CHECKSUM_NONE;
 444                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 445                         head->csum = csum_add(head->csum, fp->csum);
 446                 head->truesize += fp->truesize;
 447         }
 448         sub_frag_mem_limit(&fq->q, head->truesize);
 449
 450         head->ignore_df = 1;
 451         head->next = NULL;
 452         head->dev = dev;
 453         head->tstamp = fq->q.stamp;
 454         ipv6_hdr(head)->payload_len = htons(payload_len);
 455         ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
 456         IP6CB(head)->frag_max_size = sizeof(struct ipv6hdr) + fq->q.max_size;
 457
 458         /* Yes, and fold redundant checksum back. 8) */
 459         if (head->ip_summed == CHECKSUM_COMPLETE)
 460                 head->csum = csum_partial(skb_network_header(head),
 461                                           skb_network_header_len(head),
 462                                           head->csum);
 463
 464         fq->q.fragments = NULL;
 465         fq->q.fragments_tail = NULL;
 466
 467         /* all original skbs are linked into the NFCT_FRAG6_CB(head).orig */
 468         fp = skb_shinfo(head)->frag_list;
 469         if (fp && NFCT_FRAG6_CB(fp)->orig == NULL)
 470                 /* at above code, head skb is divided into two skbs. */
 471                 fp = fp->next;
 472
 473         op = NFCT_FRAG6_CB(head)->orig;
 474         for (; fp; fp = fp->next) {
 475                 struct sk_buff *orig = NFCT_FRAG6_CB(fp)->orig;
 476
 477                 op->next = orig;
 478                 op = orig;
 479                 NFCT_FRAG6_CB(fp)->orig = NULL;
 480         }
 481
 482         return head;
 483
 484 out_oversize:
 485         net_dbg_ratelimited("nf_ct_frag6_reasm: payload len = %d\n",
 486                             payload_len);
 487         goto out_fail;
 488 out_oom:
 489         net_dbg_ratelimited("nf_ct_frag6_reasm: no memory for reassembly\n");
 490 out_fail:
 491         return NULL;
 492 }
 493
 494 /*
 495  * find the header just before Fragment Header.
 496  *
 497  * if success return 0 and set ...
 498  * (*prevhdrp): the value of "Next Header Field" in the header
 499  *              just before Fragment Header.
 500  * (*prevhoff): the offset of "Next Header Field" in the header
 501  *              just before Fragment Header.
 502  * (*fhoff)   : the offset of Fragment Header.
 503  *
 504  * Based on ipv6_skip_hdr() in net/ipv6/exthdr.c
 505  *
 506  */
 507 static int
 508 find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff)
 509 {
 510         u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 511         const int netoff = skb_network_offset(skb);
 512         u8 prev_nhoff = netoff + offsetof(struct ipv6hdr, nexthdr);
 513         int start = netoff + sizeof(struct ipv6hdr);
 514         int len = skb->len - start;
 515         u8 prevhdr = NEXTHDR_IPV6;
 516
 517         while (nexthdr != NEXTHDR_FRAGMENT) {
 518                 struct ipv6_opt_hdr hdr;
 519                 int hdrlen;
 520
 521                 if (!ipv6_ext_hdr(nexthdr)) {
 522                         return -1;
 523                 }
 524                 if (nexthdr == NEXTHDR_NONE) {
 525                         pr_debug("next header is none\n");
 526                         return -1;
 527                 }
 528                 if (len < (int)sizeof(struct ipv6_opt_hdr)) {
 529                         pr_debug("too short\n");
 530                         return -1;
 531                 }
 532                 if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
 533                         BUG();
 534                 if (nexthdr == NEXTHDR_AUTH)
 535                         hdrlen = (hdr.hdrlen+2)<<2;
 536                 else
 537                         hdrlen = ipv6_optlen(&hdr);
 538
 539                 prevhdr = nexthdr;
 540                 prev_nhoff = start;
 541
 542                 nexthdr = hdr.nexthdr;
 543                 len -= hdrlen;
 544                 start += hdrlen;
 545         }
 546
 547         if (len < 0)
 548                 return -1;
 549
 550         *prevhdrp = prevhdr;
 551         *prevhoff = prev_nhoff;
 552         *fhoff = start;
 553
 554         return 0;
 555 }
 556
 557 struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user)
 558 {
 559         struct sk_buff *clone;
 560         struct net_device *dev = skb->dev;
 561         struct net *net = skb_dst(skb) ? dev_net(skb_dst(skb)->dev)
 562                                        : dev_net(skb->dev);
 563         struct frag_hdr *fhdr;
 564         struct frag_queue *fq;
 565         struct ipv6hdr *hdr;
 566         int fhoff, nhoff;
 567         u8 prevhdr;
 568         struct sk_buff *ret_skb = NULL;
 569
 570         /* Jumbo payload inhibits frag. header */
 571         if (ipv6_hdr(skb)->payload_len == 0) {
 572                 pr_debug("payload len = 0\n");
 573                 return skb;
 574         }
 575
 576         if (find_prev_fhdr(skb, &prevhdr, &nhoff, &fhoff) < 0)
 577                 return skb;
 578
 579         clone = skb_clone(skb, GFP_ATOMIC);
 580         if (clone == NULL) {
 581                 pr_debug("Can't clone skb\n");
 582                 return skb;
 583         }
 584
 585         NFCT_FRAG6_CB(clone)->orig = skb;
 586
 587         if (!pskb_may_pull(clone, fhoff + sizeof(*fhdr))) {
 588                 pr_debug("message is too short.\n");
 589                 goto ret_orig;
 590         }
 591
 592         skb_set_transport_header(clone, fhoff);
 593         hdr = ipv6_hdr(clone);
 594         fhdr = (struct frag_hdr *)skb_transport_header(clone);
 595
 596         fq = fq_find(net, fhdr->identification, user, &hdr->saddr, &hdr->daddr,
 597                      ip6_frag_ecn(hdr));
 598         if (fq == NULL) {
 599                 pr_debug("Can't find and can't create new queue\n");
 600                 goto ret_orig;
 601         }
 602
 603         spin_lock_bh(&fq->q.lock);
 604
 605         if (nf_ct_frag6_queue(fq, clone, fhdr, nhoff) < 0) {
 606                 spin_unlock_bh(&fq->q.lock);
 607                 pr_debug("Can't insert skb to queue\n");
 608                 inet_frag_put(&fq->q, &nf_frags);
 609                 goto ret_orig;
 610         }
 611
 612         if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 613             fq->q.meat == fq->q.len) {
 614                 ret_skb = nf_ct_frag6_reasm(fq, dev);
 615                 if (ret_skb == NULL)
 616                         pr_debug("Can't reassemble fragmented packets\n");
 617         }
 618         spin_unlock_bh(&fq->q.lock);
 619
 620         inet_frag_put(&fq->q, &nf_frags);
 621         return ret_skb;
 622
 623 ret_orig:
 624         kfree_skb(clone);
 625         return skb;
 626 }
 627
 628 void nf_ct_frag6_consume_orig(struct sk_buff *skb)
 629 {
 630         struct sk_buff *s, *s2;
 631
 632         for (s = NFCT_FRAG6_CB(skb)->orig; s;) {
 633                 s2 = s->next;
 634                 s->next = NULL;
 635                 consume_skb(s);
 636                 s = s2;
 637         }
 638 }
 639
 640 static int nf_ct_net_init(struct net *net)
 641 {
 642         net->nf_frag.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
 643         net->nf_frag.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
 644         net->nf_frag.frags.timeout = IPV6_FRAG_TIMEOUT;
 645         inet_frags_init_net(&net->nf_frag.frags);
 646
 647         return nf_ct_frag6_sysctl_register(net);
 648 }
 649
 650 static void nf_ct_net_exit(struct net *net)
 651 {
 652         nf_ct_frags6_sysctl_unregister(net);
 653         inet_frags_exit_net(&net->nf_frag.frags, &nf_frags);
 654 }
 655
 656 static struct pernet_operations nf_ct_net_ops = {
 657         .init = nf_ct_net_init,
 658         .exit = nf_ct_net_exit,
 659 };
 660
 661 int nf_ct_frag6_init(void)
 662 {
 663         int ret = 0;
 664
 665         nf_frags.hashfn = nf_hashfn;
 666         nf_frags.constructor = ip6_frag_init;
 667         nf_frags.destructor = NULL;
 668         nf_frags.skb_free = nf_skb_free;
 669         nf_frags.qsize = sizeof(struct frag_queue);
 670         nf_frags.match = ip6_frag_match;
 671         nf_frags.frag_expire = nf_ct_frag6_expire;
 672         inet_frags_init(&nf_frags);
 673
 674         ret = register_pernet_subsys(&nf_ct_net_ops);
 675         if (ret)
 676                 inet_frags_fini(&nf_frags);
 677
 678         return ret;
 679 }
 680
 681 void nf_ct_frag6_cleanup(void)
 682 {
 683         unregister_pernet_subsys(&nf_ct_net_ops);
 684         inet_frags_fini(&nf_frags);
 685 }