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 #include <linux/errno.h>
  18 #include <linux/types.h>
  19 #include <linux/string.h>
  20 #include <linux/socket.h>
  21 #include <linux/sockios.h>
  22 #include <linux/jiffies.h>
  23 #include <linux/net.h>
  24 #include <linux/list.h>
  25 #include <linux/netdevice.h>
  26 #include <linux/in6.h>
  27 #include <linux/ipv6.h>
  28 #include <linux/icmpv6.h>
  29 #include <linux/random.h>
  30
  31 #include <net/sock.h>
  32 #include <net/snmp.h>
  33 #include <net/inet_frag.h>
  34
  35 #include <net/ipv6.h>
  36 #include <net/protocol.h>
  37 #include <net/transp_v6.h>
  38 #include <net/rawv6.h>
  39 #include <net/ndisc.h>
  40 #include <net/addrconf.h>
  41 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  42 #include <linux/sysctl.h>
  43 #include <linux/netfilter.h>
  44 #include <linux/netfilter_ipv6.h>
  45 #include <linux/kernel.h>
  46 #include <linux/module.h>
  47
  48
  49 struct nf_ct_frag6_skb_cb
  50 {
  51         struct inet6_skb_parm   h;
  52         int                     offset;
  53         struct sk_buff          *orig;
  54 };
  55
  56 #define NFCT_FRAG6_CB(skb)      ((struct nf_ct_frag6_skb_cb*)((skb)->cb))
  57
  58 struct nf_ct_frag6_queue
  59 {
  60         struct inet_frag_queue  q;
  61
  62         __be32                  id;             /* fragment id          */
  63         u32                     user;
  64         struct in6_addr         saddr;
  65         struct in6_addr         daddr;
  66
  67         unsigned int            csum;
  68         __u16                   nhoffset;
  69 };
  70
  71 static struct inet_frags nf_frags;
  72 static struct netns_frags nf_init_frags;
  73
  74 #ifdef CONFIG_SYSCTL
  75 struct ctl_table nf_ct_ipv6_sysctl_table[] = {
  76         {
  77                 .procname       = "nf_conntrack_frag6_timeout",
  78                 .data           = &nf_init_frags.timeout,
  79                 .maxlen         = sizeof(unsigned int),
  80                 .mode           = 0644,
  81                 .proc_handler   = proc_dointvec_jiffies,
  82         },
  83         {
  84                 .procname       = "nf_conntrack_frag6_low_thresh",
  85                 .data           = &nf_init_frags.low_thresh,
  86                 .maxlen         = sizeof(unsigned int),
  87                 .mode           = 0644,
  88                 .proc_handler   = proc_dointvec,
  89         },
  90         {
  91                 .procname       = "nf_conntrack_frag6_high_thresh",
  92                 .data           = &nf_init_frags.high_thresh,
  93                 .maxlen         = sizeof(unsigned int),
  94                 .mode           = 0644,
  95                 .proc_handler   = proc_dointvec,
  96         },
  97         { }
  98 };
  99 #endif
 100
 101 static unsigned int nf_hashfn(struct inet_frag_queue *q)
 102 {
 103         const struct nf_ct_frag6_queue *nq;
 104
 105         nq = container_of(q, struct nf_ct_frag6_queue, q);
 106         return inet6_hash_frag(nq->id, &nq->saddr, &nq->daddr, nf_frags.rnd);
 107 }
 108
 109 static void nf_skb_free(struct sk_buff *skb)
 110 {
 111         if (NFCT_FRAG6_CB(skb)->orig)
 112                 kfree_skb(NFCT_FRAG6_CB(skb)->orig);
 113 }
 114
 115 /* Memory Tracking Functions. */
 116 static inline void frag_kfree_skb(struct sk_buff *skb, unsigned int *work)
 117 {
 118         if (work)
 119                 *work -= skb->truesize;
 120         atomic_sub(skb->truesize, &nf_init_frags.mem);
 121         nf_skb_free(skb);
 122         kfree_skb(skb);
 123 }
 124
 125 /* Destruction primitives. */
 126
 127 static __inline__ void fq_put(struct nf_ct_frag6_queue *fq)
 128 {
 129         inet_frag_put(&fq->q, &nf_frags);
 130 }
 131
 132 /* Kill fq entry. It is not destroyed immediately,
 133  * because caller (and someone more) holds reference count.
 134  */
 135 static __inline__ void fq_kill(struct nf_ct_frag6_queue *fq)
 136 {
 137         inet_frag_kill(&fq->q, &nf_frags);
 138 }
 139
 140 static void nf_ct_frag6_evictor(void)
 141 {
 142         local_bh_disable();
 143         inet_frag_evictor(&nf_init_frags, &nf_frags);
 144         local_bh_enable();
 145 }
 146
 147 static void nf_ct_frag6_expire(unsigned long data)
 148 {
 149         struct nf_ct_frag6_queue *fq;
 150
 151         fq = container_of((struct inet_frag_queue *)data,
 152                         struct nf_ct_frag6_queue, q);
 153
 154         spin_lock(&fq->q.lock);
 155
 156         if (fq->q.last_in & INET_FRAG_COMPLETE)
 157                 goto out;
 158
 159         fq_kill(fq);
 160
 161 out:
 162         spin_unlock(&fq->q.lock);
 163         fq_put(fq);
 164 }
 165
 166 /* Creation primitives. */
 167
 168 static __inline__ struct nf_ct_frag6_queue *
 169 fq_find(__be32 id, u32 user, struct in6_addr *src, struct in6_addr *dst)
 170 {
 171         struct inet_frag_queue *q;
 172         struct ip6_create_arg arg;
 173         unsigned int hash;
 174
 175         arg.id = id;
 176         arg.user = user;
 177         arg.src = src;
 178         arg.dst = dst;
 179
 180         read_lock_bh(&nf_frags.lock);
 181         hash = inet6_hash_frag(id, src, dst, nf_frags.rnd);
 182
 183         q = inet_frag_find(&nf_init_frags, &nf_frags, &arg, hash);
 184         local_bh_enable();
 185         if (q == NULL)
 186                 goto oom;
 187
 188         return container_of(q, struct nf_ct_frag6_queue, q);
 189
 190 oom:
 191         pr_debug("Can't alloc new queue\n");
 192         return NULL;
 193 }
 194
 195
 196 static int nf_ct_frag6_queue(struct nf_ct_frag6_queue *fq, struct sk_buff *skb,
 197                              const struct frag_hdr *fhdr, int nhoff)
 198 {
 199         struct sk_buff *prev, *next;
 200         int offset, end;
 201
 202         if (fq->q.last_in & INET_FRAG_COMPLETE) {
 203                 pr_debug("Allready completed\n");
 204                 goto err;
 205         }
 206
 207         offset = ntohs(fhdr->frag_off) & ~0x7;
 208         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 209                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 210
 211         if ((unsigned int)end > IPV6_MAXPLEN) {
 212                 pr_debug("offset is too large.\n");
 213                 return -1;
 214         }
 215
 216         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 217                 const unsigned char *nh = skb_network_header(skb);
 218                 skb->csum = csum_sub(skb->csum,
 219                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 220                                                   0));
 221         }
 222
 223         /* Is this the final fragment? */
 224         if (!(fhdr->frag_off & htons(IP6_MF))) {
 225                 /* If we already have some bits beyond end
 226                  * or have different end, the segment is corrupted.
 227                  */
 228                 if (end < fq->q.len ||
 229                     ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len)) {
 230                         pr_debug("already received last fragment\n");
 231                         goto err;
 232                 }
 233                 fq->q.last_in |= INET_FRAG_LAST_IN;
 234                 fq->q.len = end;
 235         } else {
 236                 /* Check if the fragment is rounded to 8 bytes.
 237                  * Required by the RFC.
 238                  */
 239                 if (end & 0x7) {
 240                         /* RFC2460 says always send parameter problem in
 241                          * this case. -DaveM
 242                          */
 243                         pr_debug("end of fragment not rounded to 8 bytes.\n");
 244                         return -1;
 245                 }
 246                 if (end > fq->q.len) {
 247                         /* Some bits beyond end -> corruption. */
 248                         if (fq->q.last_in & INET_FRAG_LAST_IN) {
 249                                 pr_debug("last packet already reached.\n");
 250                                 goto err;
 251                         }
 252                         fq->q.len = end;
 253                 }
 254         }
 255
 256         if (end == offset)
 257                 goto err;
 258
 259         /* Point into the IP datagram 'data' part. */
 260         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) {
 261                 pr_debug("queue: message is too short.\n");
 262                 goto err;
 263         }
 264         if (pskb_trim_rcsum(skb, end - offset)) {
 265                 pr_debug("Can't trim\n");
 266                 goto err;
 267         }
 268
 269         /* Find out which fragments are in front and at the back of us
 270          * in the chain of fragments so far.  We must know where to put
 271          * this fragment, right?
 272          */
 273         prev = NULL;
 274         for (next = fq->q.fragments; next != NULL; next = next->next) {
 275                 if (NFCT_FRAG6_CB(next)->offset >= offset)
 276                         break;  /* bingo! */
 277                 prev = next;
 278         }
 279
 280         /* We found where to put this one.  Check for overlap with
 281          * preceding fragment, and, if needed, align things so that
 282          * any overlaps are eliminated.
 283          */
 284         if (prev) {
 285                 int i = (NFCT_FRAG6_CB(prev)->offset + prev->len) - offset;
 286
 287                 if (i > 0) {
 288                         offset += i;
 289                         if (end <= offset) {
 290                                 pr_debug("overlap\n");
 291                                 goto err;
 292                         }
 293                         if (!pskb_pull(skb, i)) {
 294                                 pr_debug("Can't pull\n");
 295                                 goto err;
 296                         }
 297                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 298                                 skb->ip_summed = CHECKSUM_NONE;
 299                 }
 300         }
 301
 302         /* Look for overlap with succeeding segments.
 303          * If we can merge fragments, do it.
 304          */
 305         while (next && NFCT_FRAG6_CB(next)->offset < end) {
 306                 /* overlap is 'i' bytes */
 307                 int i = end - NFCT_FRAG6_CB(next)->offset;
 308
 309                 if (i < next->len) {
 310                         /* Eat head of the next overlapped fragment
 311                          * and leave the loop. The next ones cannot overlap.
 312                          */
 313                         pr_debug("Eat head of the overlapped parts.: %d", i);
 314                         if (!pskb_pull(next, i))
 315                                 goto err;
 316
 317                         /* next fragment */
 318                         NFCT_FRAG6_CB(next)->offset += i;
 319                         fq->q.meat -= i;
 320                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 321                                 next->ip_summed = CHECKSUM_NONE;
 322                         break;
 323                 } else {
 324                         struct sk_buff *free_it = next;
 325
 326                         /* Old fragmnet is completely overridden with
 327                          * new one drop it.
 328                          */
 329                         next = next->next;
 330
 331                         if (prev)
 332                                 prev->next = next;
 333                         else
 334                                 fq->q.fragments = next;
 335
 336                         fq->q.meat -= free_it->len;
 337                         frag_kfree_skb(free_it, NULL);
 338                 }
 339         }
 340
 341         NFCT_FRAG6_CB(skb)->offset = offset;
 342
 343         /* Insert this fragment in the chain of fragments. */
 344         skb->next = next;
 345         if (prev)
 346                 prev->next = skb;
 347         else
 348                 fq->q.fragments = skb;
 349
 350         skb->dev = NULL;
 351         fq->q.stamp = skb->tstamp;
 352         fq->q.meat += skb->len;
 353         atomic_add(skb->truesize, &nf_init_frags.mem);
 354
 355         /* The first fragment.
 356          * nhoffset is obtained from the first fragment, of course.
 357          */
 358         if (offset == 0) {
 359                 fq->nhoffset = nhoff;
 360                 fq->q.last_in |= INET_FRAG_FIRST_IN;
 361         }
 362         write_lock(&nf_frags.lock);
 363         list_move_tail(&fq->q.lru_list, &nf_init_frags.lru_list);
 364         write_unlock(&nf_frags.lock);
 365         return 0;
 366
 367 err:
 368         return -1;
 369 }
 370
 371 /*
 372  *      Check if this packet is complete.
 373  *      Returns NULL on failure by any reason, and pointer
 374  *      to current nexthdr field in reassembled frame.
 375  *
 376  *      It is called with locked fq, and caller must check that
 377  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 378  *      the last and the first frames arrived and all the bits are here.
 379  */
 380 static struct sk_buff *
 381 nf_ct_frag6_reasm(struct nf_ct_frag6_queue *fq, struct net_device *dev)
 382 {
 383         struct sk_buff *fp, *op, *head = fq->q.fragments;
 384         int    payload_len;
 385
 386         fq_kill(fq);
 387
 388         WARN_ON(head == NULL);
 389         WARN_ON(NFCT_FRAG6_CB(head)->offset != 0);
 390
 391         /* Unfragmented part is taken from the first segment. */
 392         payload_len = ((head->data - skb_network_header(head)) -
 393                        sizeof(struct ipv6hdr) + fq->q.len -
 394                        sizeof(struct frag_hdr));
 395         if (payload_len > IPV6_MAXPLEN) {
 396                 pr_debug("payload len is too large.\n");
 397                 goto out_oversize;
 398         }
 399
 400         /* Head of list must not be cloned. */
 401         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) {
 402                 pr_debug("skb is cloned but can't expand head");
 403                 goto out_oom;
 404         }
 405
 406         /* If the first fragment is fragmented itself, we split
 407          * it to two chunks: the first with data and paged part
 408          * and the second, holding only fragments. */
 409         if (skb_has_frags(head)) {
 410                 struct sk_buff *clone;
 411                 int i, plen = 0;
 412
 413                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) {
 414                         pr_debug("Can't alloc skb\n");
 415                         goto out_oom;
 416                 }
 417                 clone->next = head->next;
 418                 head->next = clone;
 419                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 420                 skb_frag_list_init(head);
 421                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 422                         plen += skb_shinfo(head)->frags[i].size;
 423                 clone->len = clone->data_len = head->data_len - plen;
 424                 head->data_len -= clone->len;
 425                 head->len -= clone->len;
 426                 clone->csum = 0;
 427                 clone->ip_summed = head->ip_summed;
 428
 429                 NFCT_FRAG6_CB(clone)->orig = NULL;
 430                 atomic_add(clone->truesize, &nf_init_frags.mem);
 431         }
 432
 433         /* We have to remove fragment header from datagram and to relocate
 434          * header in order to calculate ICV correctly. */
 435         skb_network_header(head)[fq->nhoffset] = skb_transport_header(head)[0];
 436         memmove(head->head + sizeof(struct frag_hdr), head->head,
 437                 (head->data - head->head) - sizeof(struct frag_hdr));
 438         head->mac_header += sizeof(struct frag_hdr);
 439         head->network_header += sizeof(struct frag_hdr);
 440
 441         skb_shinfo(head)->frag_list = head->next;
 442         skb_reset_transport_header(head);
 443         skb_push(head, head->data - skb_network_header(head));
 444         atomic_sub(head->truesize, &nf_init_frags.mem);
 445
 446         for (fp=head->next; fp; fp = fp->next) {
 447                 head->data_len += fp->len;
 448                 head->len += fp->len;
 449                 if (head->ip_summed != fp->ip_summed)
 450                         head->ip_summed = CHECKSUM_NONE;
 451                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 452                         head->csum = csum_add(head->csum, fp->csum);
 453                 head->truesize += fp->truesize;
 454                 atomic_sub(fp->truesize, &nf_init_frags.mem);
 455         }
 456
 457         head->next = NULL;
 458         head->dev = dev;
 459         head->tstamp = fq->q.stamp;
 460         ipv6_hdr(head)->payload_len = htons(payload_len);
 461
 462         /* Yes, and fold redundant checksum back. 8) */
 463         if (head->ip_summed == CHECKSUM_COMPLETE)
 464                 head->csum = csum_partial(skb_network_header(head),
 465                                           skb_network_header_len(head),
 466                                           head->csum);
 467
 468         fq->q.fragments = NULL;
 469
 470         /* all original skbs are linked into the NFCT_FRAG6_CB(head).orig */
 471         fp = skb_shinfo(head)->frag_list;
 472         if (fp && NFCT_FRAG6_CB(fp)->orig == NULL)
 473                 /* at above code, head skb is divided into two skbs. */
 474                 fp = fp->next;
 475
 476         op = NFCT_FRAG6_CB(head)->orig;
 477         for (; fp; fp = fp->next) {
 478                 struct sk_buff *orig = NFCT_FRAG6_CB(fp)->orig;
 479
 480                 op->next = orig;
 481                 op = orig;
 482                 NFCT_FRAG6_CB(fp)->orig = NULL;
 483         }
 484
 485         return head;
 486
 487 out_oversize:
 488         if (net_ratelimit())
 489                 printk(KERN_DEBUG "nf_ct_frag6_reasm: payload len = %d\n", payload_len);
 490         goto out_fail;
 491 out_oom:
 492         if (net_ratelimit())
 493                 printk(KERN_DEBUG "nf_ct_frag6_reasm: no memory for reassembly\n");
 494 out_fail:
 495         return NULL;
 496 }
 497
 498 /*
 499  * find the header just before Fragment Header.
 500  *
 501  * if success return 0 and set ...
 502  * (*prevhdrp): the value of "Next Header Field" in the header
 503  *              just before Fragment Header.
 504  * (*prevhoff): the offset of "Next Header Field" in the header
 505  *              just before Fragment Header.
 506  * (*fhoff)   : the offset of Fragment Header.
 507  *
 508  * Based on ipv6_skip_hdr() in net/ipv6/exthdr.c
 509  *
 510  */
 511 static int
 512 find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff)
 513 {
 514         u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 515         const int netoff = skb_network_offset(skb);
 516         u8 prev_nhoff = netoff + offsetof(struct ipv6hdr, nexthdr);
 517         int start = netoff + sizeof(struct ipv6hdr);
 518         int len = skb->len - start;
 519         u8 prevhdr = NEXTHDR_IPV6;
 520
 521         while (nexthdr != NEXTHDR_FRAGMENT) {
 522                 struct ipv6_opt_hdr hdr;
 523                 int hdrlen;
 524
 525                 if (!ipv6_ext_hdr(nexthdr)) {
 526                         return -1;
 527                 }
 528                 if (nexthdr == NEXTHDR_NONE) {
 529                         pr_debug("next header is none\n");
 530                         return -1;
 531                 }
 532                 if (len < (int)sizeof(struct ipv6_opt_hdr)) {
 533                         pr_debug("too short\n");
 534                         return -1;
 535                 }
 536                 if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
 537                         BUG();
 538                 if (nexthdr == NEXTHDR_AUTH)
 539                         hdrlen = (hdr.hdrlen+2)<<2;
 540                 else
 541                         hdrlen = ipv6_optlen(&hdr);
 542
 543                 prevhdr = nexthdr;
 544                 prev_nhoff = start;
 545
 546                 nexthdr = hdr.nexthdr;
 547                 len -= hdrlen;
 548                 start += hdrlen;
 549         }
 550
 551         if (len < 0)
 552                 return -1;
 553
 554         *prevhdrp = prevhdr;
 555         *prevhoff = prev_nhoff;
 556         *fhoff = start;
 557
 558         return 0;
 559 }
 560
 561 struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user)
 562 {
 563         struct sk_buff *clone;
 564         struct net_device *dev = skb->dev;
 565         struct frag_hdr *fhdr;
 566         struct nf_ct_frag6_queue *fq;
 567         struct ipv6hdr *hdr;
 568         int fhoff, nhoff;
 569         u8 prevhdr;
 570         struct sk_buff *ret_skb = NULL;
 571
 572         /* Jumbo payload inhibits frag. header */
 573         if (ipv6_hdr(skb)->payload_len == 0) {
 574                 pr_debug("payload len = 0\n");
 575                 return skb;
 576         }
 577
 578         if (find_prev_fhdr(skb, &prevhdr, &nhoff, &fhoff) < 0)
 579                 return skb;
 580
 581         clone = skb_clone(skb, GFP_ATOMIC);
 582         if (clone == NULL) {
 583                 pr_debug("Can't clone skb\n");
 584                 return skb;
 585         }
 586
 587         NFCT_FRAG6_CB(clone)->orig = skb;
 588
 589         if (!pskb_may_pull(clone, fhoff + sizeof(*fhdr))) {
 590                 pr_debug("message is too short.\n");
 591                 goto ret_orig;
 592         }
 593
 594         skb_set_transport_header(clone, fhoff);
 595         hdr = ipv6_hdr(clone);
 596         fhdr = (struct frag_hdr *)skb_transport_header(clone);
 597
 598         if (atomic_read(&nf_init_frags.mem) > nf_init_frags.high_thresh)
 599                 nf_ct_frag6_evictor();
 600
 601         fq = fq_find(fhdr->identification, user, &hdr->saddr, &hdr->daddr);
 602         if (fq == NULL) {
 603                 pr_debug("Can't find and can't create new queue\n");
 604                 goto ret_orig;
 605         }
 606
 607         spin_lock_bh(&fq->q.lock);
 608
 609         if (nf_ct_frag6_queue(fq, clone, fhdr, nhoff) < 0) {
 610                 spin_unlock_bh(&fq->q.lock);
 611                 pr_debug("Can't insert skb to queue\n");
 612                 fq_put(fq);
 613                 goto ret_orig;
 614         }
 615
 616         if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 617             fq->q.meat == fq->q.len) {
 618                 ret_skb = nf_ct_frag6_reasm(fq, dev);
 619                 if (ret_skb == NULL)
 620                         pr_debug("Can't reassemble fragmented packets\n");
 621         }
 622         spin_unlock_bh(&fq->q.lock);
 623
 624         fq_put(fq);
 625         return ret_skb;
 626
 627 ret_orig:
 628         kfree_skb(clone);
 629         return skb;
 630 }
 631
 632 void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
 633                         struct net_device *in, struct net_device *out,
 634                         int (*okfn)(struct sk_buff *))
 635 {
 636         struct sk_buff *s, *s2;
 637
 638         for (s = NFCT_FRAG6_CB(skb)->orig; s;) {
 639                 nf_conntrack_put_reasm(s->nfct_reasm);
 640                 nf_conntrack_get_reasm(skb);
 641                 s->nfct_reasm = skb;
 642
 643                 s2 = s->next;
 644                 s->next = NULL;
 645
 646                 NF_HOOK_THRESH(PF_INET6, hooknum, s, in, out, okfn,
 647                                NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
 648                 s = s2;
 649         }
 650         nf_conntrack_put_reasm(skb);
 651 }
 652
 653 int nf_ct_frag6_init(void)
 654 {
 655         nf_frags.hashfn = nf_hashfn;
 656         nf_frags.constructor = ip6_frag_init;
 657         nf_frags.destructor = NULL;
 658         nf_frags.skb_free = nf_skb_free;
 659         nf_frags.qsize = sizeof(struct nf_ct_frag6_queue);
 660         nf_frags.match = ip6_frag_match;
 661         nf_frags.frag_expire = nf_ct_frag6_expire;
 662         nf_frags.secret_interval = 10 * 60 * HZ;
 663         nf_init_frags.timeout = IPV6_FRAG_TIMEOUT;
 664         nf_init_frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
 665         nf_init_frags.low_thresh = IPV6_FRAG_LOW_THRESH;
 666         inet_frags_init_net(&nf_init_frags);
 667         inet_frags_init(&nf_frags);
 668
 669         return 0;
 670 }
 671
 672 void nf_ct_frag6_cleanup(void)
 673 {
 674         inet_frags_fini(&nf_frags);
 675
 676         nf_init_frags.low_thresh = 0;
 677         nf_ct_frag6_evictor();
 678 }