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 #include <linux/slab.h>
  31
  32 #include <net/sock.h>
  33 #include <net/snmp.h>
  34 #include <net/inet_frag.h>
  35
  36 #include <net/ipv6.h>
  37 #include <net/protocol.h>
  38 #include <net/transp_v6.h>
  39 #include <net/rawv6.h>
  40 #include <net/ndisc.h>
  41 #include <net/addrconf.h>
  42 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
  43 #include <linux/sysctl.h>
  44 #include <linux/netfilter.h>
  45 #include <linux/netfilter_ipv6.h>
  46 #include <linux/kernel.h>
  47 #include <linux/module.h>
  48
  49
  50 struct nf_ct_frag6_skb_cb
  51 {
  52         struct inet6_skb_parm   h;
  53         int                     offset;
  54         struct sk_buff          *orig;
  55 };
  56
  57 #define NFCT_FRAG6_CB(skb)      ((struct nf_ct_frag6_skb_cb*)((skb)->cb))
  58
  59 struct nf_ct_frag6_queue
  60 {
  61         struct inet_frag_queue  q;
  62
  63         __be32                  id;             /* fragment id          */
  64         u32                     user;
  65         struct in6_addr         saddr;
  66         struct in6_addr         daddr;
  67
  68         unsigned int            csum;
  69         __u16                   nhoffset;
  70 };
  71
  72 static struct inet_frags nf_frags;
  73 static struct netns_frags nf_init_frags;
  74
  75 #ifdef CONFIG_SYSCTL
  76 struct ctl_table nf_ct_frag6_sysctl_table[] = {
  77         {
  78                 .procname       = "nf_conntrack_frag6_timeout",
  79                 .data           = &nf_init_frags.timeout,
  80                 .maxlen         = sizeof(unsigned int),
  81                 .mode           = 0644,
  82                 .proc_handler   = proc_dointvec_jiffies,
  83         },
  84         {
  85                 .procname       = "nf_conntrack_frag6_low_thresh",
  86                 .data           = &nf_init_frags.low_thresh,
  87                 .maxlen         = sizeof(unsigned int),
  88                 .mode           = 0644,
  89                 .proc_handler   = proc_dointvec,
  90         },
  91         {
  92                 .procname       = "nf_conntrack_frag6_high_thresh",
  93                 .data           = &nf_init_frags.high_thresh,
  94                 .maxlen         = sizeof(unsigned int),
  95                 .mode           = 0644,
  96                 .proc_handler   = proc_dointvec,
  97         },
  98         { }
  99 };
 100
 101 static struct ctl_table_header *nf_ct_frag6_sysctl_header;
 102 #endif
 103
 104 static unsigned int nf_hashfn(struct inet_frag_queue *q)
 105 {
 106         const struct nf_ct_frag6_queue *nq;
 107
 108         nq = container_of(q, struct nf_ct_frag6_queue, q);
 109         return inet6_hash_frag(nq->id, &nq->saddr, &nq->daddr, nf_frags.rnd);
 110 }
 111
 112 static void nf_skb_free(struct sk_buff *skb)
 113 {
 114         if (NFCT_FRAG6_CB(skb)->orig)
 115                 kfree_skb(NFCT_FRAG6_CB(skb)->orig);
 116 }
 117
 118 /* Destruction primitives. */
 119
 120 static __inline__ void fq_put(struct nf_ct_frag6_queue *fq)
 121 {
 122         inet_frag_put(&fq->q, &nf_frags);
 123 }
 124
 125 /* Kill fq entry. It is not destroyed immediately,
 126  * because caller (and someone more) holds reference count.
 127  */
 128 static __inline__ void fq_kill(struct nf_ct_frag6_queue *fq)
 129 {
 130         inet_frag_kill(&fq->q, &nf_frags);
 131 }
 132
 133 static void nf_ct_frag6_evictor(void)
 134 {
 135         local_bh_disable();
 136         inet_frag_evictor(&nf_init_frags, &nf_frags);
 137         local_bh_enable();
 138 }
 139
 140 static void nf_ct_frag6_expire(unsigned long data)
 141 {
 142         struct nf_ct_frag6_queue *fq;
 143
 144         fq = container_of((struct inet_frag_queue *)data,
 145                         struct nf_ct_frag6_queue, q);
 146
 147         spin_lock(&fq->q.lock);
 148
 149         if (fq->q.last_in & INET_FRAG_COMPLETE)
 150                 goto out;
 151
 152         fq_kill(fq);
 153
 154 out:
 155         spin_unlock(&fq->q.lock);
 156         fq_put(fq);
 157 }
 158
 159 /* Creation primitives. */
 160
 161 static __inline__ struct nf_ct_frag6_queue *
 162 fq_find(__be32 id, u32 user, struct in6_addr *src, struct in6_addr *dst)
 163 {
 164         struct inet_frag_queue *q;
 165         struct ip6_create_arg arg;
 166         unsigned int hash;
 167
 168         arg.id = id;
 169         arg.user = user;
 170         arg.src = src;
 171         arg.dst = dst;
 172
 173         read_lock_bh(&nf_frags.lock);
 174         hash = inet6_hash_frag(id, src, dst, nf_frags.rnd);
 175
 176         q = inet_frag_find(&nf_init_frags, &nf_frags, &arg, hash);
 177         local_bh_enable();
 178         if (q == NULL)
 179                 goto oom;
 180
 181         return container_of(q, struct nf_ct_frag6_queue, q);
 182
 183 oom:
 184         pr_debug("Can't alloc new queue\n");
 185         return NULL;
 186 }
 187
 188
 189 static int nf_ct_frag6_queue(struct nf_ct_frag6_queue *fq, struct sk_buff *skb,
 190                              const struct frag_hdr *fhdr, int nhoff)
 191 {
 192         struct sk_buff *prev, *next;
 193         int offset, end;
 194
 195         if (fq->q.last_in & INET_FRAG_COMPLETE) {
 196                 pr_debug("Already completed\n");
 197                 goto err;
 198         }
 199
 200         offset = ntohs(fhdr->frag_off) & ~0x7;
 201         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 202                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 203
 204         if ((unsigned int)end > IPV6_MAXPLEN) {
 205                 pr_debug("offset is too large.\n");
 206                 return -1;
 207         }
 208
 209         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 210                 const unsigned char *nh = skb_network_header(skb);
 211                 skb->csum = csum_sub(skb->csum,
 212                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 213                                                   0));
 214         }
 215
 216         /* Is this the final fragment? */
 217         if (!(fhdr->frag_off & htons(IP6_MF))) {
 218                 /* If we already have some bits beyond end
 219                  * or have different end, the segment is corrupted.
 220                  */
 221                 if (end < fq->q.len ||
 222                     ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len)) {
 223                         pr_debug("already received last fragment\n");
 224                         goto err;
 225                 }
 226                 fq->q.last_in |= INET_FRAG_LAST_IN;
 227                 fq->q.len = end;
 228         } else {
 229                 /* Check if the fragment is rounded to 8 bytes.
 230                  * Required by the RFC.
 231                  */
 232                 if (end & 0x7) {
 233                         /* RFC2460 says always send parameter problem in
 234                          * this case. -DaveM
 235                          */
 236                         pr_debug("end of fragment not rounded to 8 bytes.\n");
 237                         return -1;
 238                 }
 239                 if (end > fq->q.len) {
 240                         /* Some bits beyond end -> corruption. */
 241                         if (fq->q.last_in & INET_FRAG_LAST_IN) {
 242                                 pr_debug("last packet already reached.\n");
 243                                 goto err;
 244                         }
 245                         fq->q.len = end;
 246                 }
 247         }
 248
 249         if (end == offset)
 250                 goto err;
 251
 252         /* Point into the IP datagram 'data' part. */
 253         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) {
 254                 pr_debug("queue: message is too short.\n");
 255                 goto err;
 256         }
 257         if (pskb_trim_rcsum(skb, end - offset)) {
 258                 pr_debug("Can't trim\n");
 259                 goto err;
 260         }
 261
 262         /* Find out which fragments are in front and at the back of us
 263          * in the chain of fragments so far.  We must know where to put
 264          * this fragment, right?
 265          */
 266         prev = fq->q.fragments_tail;
 267         if (!prev || NFCT_FRAG6_CB(prev)->offset < offset) {
 268                 next = NULL;
 269                 goto found;
 270         }
 271         prev = NULL;
 272         for (next = fq->q.fragments; next != NULL; next = next->next) {
 273                 if (NFCT_FRAG6_CB(next)->offset >= offset)
 274                         break;  /* bingo! */
 275                 prev = next;
 276         }
 277
 278 found:
 279         /* RFC5722, Section 4:
 280          *                                  When reassembling an IPv6 datagram, if
 281          *   one or more its constituent fragments is determined to be an
 282          *   overlapping fragment, the entire datagram (and any constituent
 283          *   fragments, including those not yet received) MUST be silently
 284          *   discarded.
 285          */
 286
 287         /* Check for overlap with preceding fragment. */
 288         if (prev &&
 289             (NFCT_FRAG6_CB(prev)->offset + prev->len) - offset > 0)
 290                 goto discard_fq;
 291
 292         /* Look for overlap with succeeding segment. */
 293         if (next && NFCT_FRAG6_CB(next)->offset < end)
 294                 goto discard_fq;
 295
 296         NFCT_FRAG6_CB(skb)->offset = offset;
 297
 298         /* Insert this fragment in the chain of fragments. */
 299         skb->next = next;
 300         if (!next)
 301                 fq->q.fragments_tail = skb;
 302         if (prev)
 303                 prev->next = skb;
 304         else
 305                 fq->q.fragments = skb;
 306
 307         skb->dev = NULL;
 308         fq->q.stamp = skb->tstamp;
 309         fq->q.meat += skb->len;
 310         atomic_add(skb->truesize, &nf_init_frags.mem);
 311
 312         /* The first fragment.
 313          * nhoffset is obtained from the first fragment, of course.
 314          */
 315         if (offset == 0) {
 316                 fq->nhoffset = nhoff;
 317                 fq->q.last_in |= INET_FRAG_FIRST_IN;
 318         }
 319         write_lock(&nf_frags.lock);
 320         list_move_tail(&fq->q.lru_list, &nf_init_frags.lru_list);
 321         write_unlock(&nf_frags.lock);
 322         return 0;
 323
 324 discard_fq:
 325         fq_kill(fq);
 326 err:
 327         return -1;
 328 }
 329
 330 /*
 331  *      Check if this packet is complete.
 332  *      Returns NULL on failure by any reason, and pointer
 333  *      to current nexthdr field in reassembled frame.
 334  *
 335  *      It is called with locked fq, and caller must check that
 336  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 337  *      the last and the first frames arrived and all the bits are here.
 338  */
 339 static struct sk_buff *
 340 nf_ct_frag6_reasm(struct nf_ct_frag6_queue *fq, struct net_device *dev)
 341 {
 342         struct sk_buff *fp, *op, *head = fq->q.fragments;
 343         int    payload_len;
 344
 345         fq_kill(fq);
 346
 347         WARN_ON(head == NULL);
 348         WARN_ON(NFCT_FRAG6_CB(head)->offset != 0);
 349
 350         /* Unfragmented part is taken from the first segment. */
 351         payload_len = ((head->data - skb_network_header(head)) -
 352                        sizeof(struct ipv6hdr) + fq->q.len -
 353                        sizeof(struct frag_hdr));
 354         if (payload_len > IPV6_MAXPLEN) {
 355                 pr_debug("payload len is too large.\n");
 356                 goto out_oversize;
 357         }
 358
 359         /* Head of list must not be cloned. */
 360         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) {
 361                 pr_debug("skb is cloned but can't expand head");
 362                 goto out_oom;
 363         }
 364
 365         /* If the first fragment is fragmented itself, we split
 366          * it to two chunks: the first with data and paged part
 367          * and the second, holding only fragments. */
 368         if (skb_has_frag_list(head)) {
 369                 struct sk_buff *clone;
 370                 int i, plen = 0;
 371
 372                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) {
 373                         pr_debug("Can't alloc skb\n");
 374                         goto out_oom;
 375                 }
 376                 clone->next = head->next;
 377                 head->next = clone;
 378                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 379                 skb_frag_list_init(head);
 380                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 381                         plen += skb_shinfo(head)->frags[i].size;
 382                 clone->len = clone->data_len = head->data_len - plen;
 383                 head->data_len -= clone->len;
 384                 head->len -= clone->len;
 385                 clone->csum = 0;
 386                 clone->ip_summed = head->ip_summed;
 387
 388                 NFCT_FRAG6_CB(clone)->orig = NULL;
 389                 atomic_add(clone->truesize, &nf_init_frags.mem);
 390         }
 391
 392         /* We have to remove fragment header from datagram and to relocate
 393          * header in order to calculate ICV correctly. */
 394         skb_network_header(head)[fq->nhoffset] = skb_transport_header(head)[0];
 395         memmove(head->head + sizeof(struct frag_hdr), head->head,
 396                 (head->data - head->head) - sizeof(struct frag_hdr));
 397         head->mac_header += sizeof(struct frag_hdr);
 398         head->network_header += sizeof(struct frag_hdr);
 399
 400         skb_shinfo(head)->frag_list = head->next;
 401         skb_reset_transport_header(head);
 402         skb_push(head, head->data - skb_network_header(head));
 403
 404         for (fp=head->next; fp; fp = fp->next) {
 405                 head->data_len += fp->len;
 406                 head->len += fp->len;
 407                 if (head->ip_summed != fp->ip_summed)
 408                         head->ip_summed = CHECKSUM_NONE;
 409                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 410                         head->csum = csum_add(head->csum, fp->csum);
 411                 head->truesize += fp->truesize;
 412         }
 413         atomic_sub(head->truesize, &nf_init_frags.mem);
 414
 415         head->next = NULL;
 416         head->dev = dev;
 417         head->tstamp = fq->q.stamp;
 418         ipv6_hdr(head)->payload_len = htons(payload_len);
 419
 420         /* Yes, and fold redundant checksum back. 8) */
 421         if (head->ip_summed == CHECKSUM_COMPLETE)
 422                 head->csum = csum_partial(skb_network_header(head),
 423                                           skb_network_header_len(head),
 424                                           head->csum);
 425
 426         fq->q.fragments = NULL;
 427         fq->q.fragments_tail = NULL;
 428
 429         /* all original skbs are linked into the NFCT_FRAG6_CB(head).orig */
 430         fp = skb_shinfo(head)->frag_list;
 431         if (fp && NFCT_FRAG6_CB(fp)->orig == NULL)
 432                 /* at above code, head skb is divided into two skbs. */
 433                 fp = fp->next;
 434
 435         op = NFCT_FRAG6_CB(head)->orig;
 436         for (; fp; fp = fp->next) {
 437                 struct sk_buff *orig = NFCT_FRAG6_CB(fp)->orig;
 438
 439                 op->next = orig;
 440                 op = orig;
 441                 NFCT_FRAG6_CB(fp)->orig = NULL;
 442         }
 443
 444         return head;
 445
 446 out_oversize:
 447         if (net_ratelimit())
 448                 printk(KERN_DEBUG "nf_ct_frag6_reasm: payload len = %d\n", payload_len);
 449         goto out_fail;
 450 out_oom:
 451         if (net_ratelimit())
 452                 printk(KERN_DEBUG "nf_ct_frag6_reasm: no memory for reassembly\n");
 453 out_fail:
 454         return NULL;
 455 }
 456
 457 /*
 458  * find the header just before Fragment Header.
 459  *
 460  * if success return 0 and set ...
 461  * (*prevhdrp): the value of "Next Header Field" in the header
 462  *              just before Fragment Header.
 463  * (*prevhoff): the offset of "Next Header Field" in the header
 464  *              just before Fragment Header.
 465  * (*fhoff)   : the offset of Fragment Header.
 466  *
 467  * Based on ipv6_skip_hdr() in net/ipv6/exthdr.c
 468  *
 469  */
 470 static int
 471 find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff)
 472 {
 473         u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 474         const int netoff = skb_network_offset(skb);
 475         u8 prev_nhoff = netoff + offsetof(struct ipv6hdr, nexthdr);
 476         int start = netoff + sizeof(struct ipv6hdr);
 477         int len = skb->len - start;
 478         u8 prevhdr = NEXTHDR_IPV6;
 479
 480         while (nexthdr != NEXTHDR_FRAGMENT) {
 481                 struct ipv6_opt_hdr hdr;
 482                 int hdrlen;
 483
 484                 if (!ipv6_ext_hdr(nexthdr)) {
 485                         return -1;
 486                 }
 487                 if (nexthdr == NEXTHDR_NONE) {
 488                         pr_debug("next header is none\n");
 489                         return -1;
 490                 }
 491                 if (len < (int)sizeof(struct ipv6_opt_hdr)) {
 492                         pr_debug("too short\n");
 493                         return -1;
 494                 }
 495                 if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
 496                         BUG();
 497                 if (nexthdr == NEXTHDR_AUTH)
 498                         hdrlen = (hdr.hdrlen+2)<<2;
 499                 else
 500                         hdrlen = ipv6_optlen(&hdr);
 501
 502                 prevhdr = nexthdr;
 503                 prev_nhoff = start;
 504
 505                 nexthdr = hdr.nexthdr;
 506                 len -= hdrlen;
 507                 start += hdrlen;
 508         }
 509
 510         if (len < 0)
 511                 return -1;
 512
 513         *prevhdrp = prevhdr;
 514         *prevhoff = prev_nhoff;
 515         *fhoff = start;
 516
 517         return 0;
 518 }
 519
 520 struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user)
 521 {
 522         struct sk_buff *clone;
 523         struct net_device *dev = skb->dev;
 524         struct frag_hdr *fhdr;
 525         struct nf_ct_frag6_queue *fq;
 526         struct ipv6hdr *hdr;
 527         int fhoff, nhoff;
 528         u8 prevhdr;
 529         struct sk_buff *ret_skb = NULL;
 530
 531         /* Jumbo payload inhibits frag. header */
 532         if (ipv6_hdr(skb)->payload_len == 0) {
 533                 pr_debug("payload len = 0\n");
 534                 return skb;
 535         }
 536
 537         if (find_prev_fhdr(skb, &prevhdr, &nhoff, &fhoff) < 0)
 538                 return skb;
 539
 540         clone = skb_clone(skb, GFP_ATOMIC);
 541         if (clone == NULL) {
 542                 pr_debug("Can't clone skb\n");
 543                 return skb;
 544         }
 545
 546         NFCT_FRAG6_CB(clone)->orig = skb;
 547
 548         if (!pskb_may_pull(clone, fhoff + sizeof(*fhdr))) {
 549                 pr_debug("message is too short.\n");
 550                 goto ret_orig;
 551         }
 552
 553         skb_set_transport_header(clone, fhoff);
 554         hdr = ipv6_hdr(clone);
 555         fhdr = (struct frag_hdr *)skb_transport_header(clone);
 556
 557         if (atomic_read(&nf_init_frags.mem) > nf_init_frags.high_thresh)
 558                 nf_ct_frag6_evictor();
 559
 560         fq = fq_find(fhdr->identification, user, &hdr->saddr, &hdr->daddr);
 561         if (fq == NULL) {
 562                 pr_debug("Can't find and can't create new queue\n");
 563                 goto ret_orig;
 564         }
 565
 566         spin_lock_bh(&fq->q.lock);
 567
 568         if (nf_ct_frag6_queue(fq, clone, fhdr, nhoff) < 0) {
 569                 spin_unlock_bh(&fq->q.lock);
 570                 pr_debug("Can't insert skb to queue\n");
 571                 fq_put(fq);
 572                 goto ret_orig;
 573         }
 574
 575         if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 576             fq->q.meat == fq->q.len) {
 577                 ret_skb = nf_ct_frag6_reasm(fq, dev);
 578                 if (ret_skb == NULL)
 579                         pr_debug("Can't reassemble fragmented packets\n");
 580         }
 581         spin_unlock_bh(&fq->q.lock);
 582
 583         fq_put(fq);
 584         return ret_skb;
 585
 586 ret_orig:
 587         kfree_skb(clone);
 588         return skb;
 589 }
 590
 591 void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
 592                         struct net_device *in, struct net_device *out,
 593                         int (*okfn)(struct sk_buff *))
 594 {
 595         struct sk_buff *s, *s2;
 596
 597         for (s = NFCT_FRAG6_CB(skb)->orig; s;) {
 598                 nf_conntrack_put_reasm(s->nfct_reasm);
 599                 nf_conntrack_get_reasm(skb);
 600                 s->nfct_reasm = skb;
 601
 602                 s2 = s->next;
 603                 s->next = NULL;
 604
 605                 NF_HOOK_THRESH(NFPROTO_IPV6, hooknum, s, in, out, okfn,
 606                                NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
 607                 s = s2;
 608         }
 609         nf_conntrack_put_reasm(skb);
 610 }
 611
 612 int nf_ct_frag6_init(void)
 613 {
 614         nf_frags.hashfn = nf_hashfn;
 615         nf_frags.constructor = ip6_frag_init;
 616         nf_frags.destructor = NULL;
 617         nf_frags.skb_free = nf_skb_free;
 618         nf_frags.qsize = sizeof(struct nf_ct_frag6_queue);
 619         nf_frags.match = ip6_frag_match;
 620         nf_frags.frag_expire = nf_ct_frag6_expire;
 621         nf_frags.secret_interval = 10 * 60 * HZ;
 622         nf_init_frags.timeout = IPV6_FRAG_TIMEOUT;
 623         nf_init_frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
 624         nf_init_frags.low_thresh = IPV6_FRAG_LOW_THRESH;
 625         inet_frags_init_net(&nf_init_frags);
 626         inet_frags_init(&nf_frags);
 627
 628 #ifdef CONFIG_SYSCTL
 629         nf_ct_frag6_sysctl_header = register_sysctl_paths(nf_net_netfilter_sysctl_path,
 630                                                           nf_ct_frag6_sysctl_table);
 631         if (!nf_ct_frag6_sysctl_header) {
 632                 inet_frags_fini(&nf_frags);
 633                 return -ENOMEM;
 634         }
 635 #endif
 636
 637         return 0;
 638 }
 639
 640 void nf_ct_frag6_cleanup(void)
 641 {
 642 #ifdef CONFIG_SYSCTL
 643         unregister_sysctl_table(nf_ct_frag6_sysctl_header);
 644         nf_ct_frag6_sysctl_header = NULL;
 645 #endif
 646         inet_frags_fini(&nf_frags);
 647
 648         nf_init_frags.low_thresh = 0;
 649         nf_ct_frag6_evictor();
 650 }