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 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
  49
  50
  51 struct nf_ct_frag6_skb_cb
  52 {
  53         struct inet6_skb_parm   h;
  54         int                     offset;
  55         struct sk_buff          *orig;
  56 };
  57
  58 #define NFCT_FRAG6_CB(skb)      ((struct nf_ct_frag6_skb_cb*)((skb)->cb))
  59
  60 struct nf_ct_frag6_queue
  61 {
  62         struct inet_frag_queue  q;
  63
  64         __be32                  id;             /* fragment id          */
  65         u32                     user;
  66         struct in6_addr         saddr;
  67         struct in6_addr         daddr;
  68
  69         unsigned int            csum;
  70         __u16                   nhoffset;
  71 };
  72
  73 static struct inet_frags nf_frags;
  74 static struct netns_frags nf_init_frags;
  75
  76 #ifdef CONFIG_SYSCTL
  77 static struct ctl_table nf_ct_frag6_sysctl_table[] = {
  78         {
  79                 .procname       = "nf_conntrack_frag6_timeout",
  80                 .data           = &nf_init_frags.timeout,
  81                 .maxlen         = sizeof(unsigned int),
  82                 .mode           = 0644,
  83                 .proc_handler   = proc_dointvec_jiffies,
  84         },
  85         {
  86                 .procname       = "nf_conntrack_frag6_low_thresh",
  87                 .data           = &nf_init_frags.low_thresh,
  88                 .maxlen         = sizeof(unsigned int),
  89                 .mode           = 0644,
  90                 .proc_handler   = proc_dointvec,
  91         },
  92         {
  93                 .procname       = "nf_conntrack_frag6_high_thresh",
  94                 .data           = &nf_init_frags.high_thresh,
  95                 .maxlen         = sizeof(unsigned int),
  96                 .mode           = 0644,
  97                 .proc_handler   = proc_dointvec,
  98         },
  99         { }
 100 };
 101
 102 static struct ctl_table_header *nf_ct_frag6_sysctl_header;
 103 #endif
 104
 105 static unsigned int nf_hashfn(struct inet_frag_queue *q)
 106 {
 107         const struct nf_ct_frag6_queue *nq;
 108
 109         nq = container_of(q, struct nf_ct_frag6_queue, q);
 110         return inet6_hash_frag(nq->id, &nq->saddr, &nq->daddr, nf_frags.rnd);
 111 }
 112
 113 static void nf_skb_free(struct sk_buff *skb)
 114 {
 115         if (NFCT_FRAG6_CB(skb)->orig)
 116                 kfree_skb(NFCT_FRAG6_CB(skb)->orig);
 117 }
 118
 119 /* Destruction primitives. */
 120
 121 static __inline__ void fq_put(struct nf_ct_frag6_queue *fq)
 122 {
 123         inet_frag_put(&fq->q, &nf_frags);
 124 }
 125
 126 /* Kill fq entry. It is not destroyed immediately,
 127  * because caller (and someone more) holds reference count.
 128  */
 129 static __inline__ void fq_kill(struct nf_ct_frag6_queue *fq)
 130 {
 131         inet_frag_kill(&fq->q, &nf_frags);
 132 }
 133
 134 static void nf_ct_frag6_evictor(void)
 135 {
 136         local_bh_disable();
 137         inet_frag_evictor(&nf_init_frags, &nf_frags);
 138         local_bh_enable();
 139 }
 140
 141 static void nf_ct_frag6_expire(unsigned long data)
 142 {
 143         struct nf_ct_frag6_queue *fq;
 144
 145         fq = container_of((struct inet_frag_queue *)data,
 146                         struct nf_ct_frag6_queue, q);
 147
 148         spin_lock(&fq->q.lock);
 149
 150         if (fq->q.last_in & INET_FRAG_COMPLETE)
 151                 goto out;
 152
 153         fq_kill(fq);
 154
 155 out:
 156         spin_unlock(&fq->q.lock);
 157         fq_put(fq);
 158 }
 159
 160 /* Creation primitives. */
 161
 162 static __inline__ struct nf_ct_frag6_queue *
 163 fq_find(__be32 id, u32 user, struct in6_addr *src, struct in6_addr *dst)
 164 {
 165         struct inet_frag_queue *q;
 166         struct ip6_create_arg arg;
 167         unsigned int hash;
 168
 169         arg.id = id;
 170         arg.user = user;
 171         arg.src = src;
 172         arg.dst = dst;
 173
 174         read_lock_bh(&nf_frags.lock);
 175         hash = inet6_hash_frag(id, src, dst, nf_frags.rnd);
 176
 177         q = inet_frag_find(&nf_init_frags, &nf_frags, &arg, hash);
 178         local_bh_enable();
 179         if (q == NULL)
 180                 goto oom;
 181
 182         return container_of(q, struct nf_ct_frag6_queue, q);
 183
 184 oom:
 185         pr_debug("Can't alloc new queue\n");
 186         return NULL;
 187 }
 188
 189
 190 static int nf_ct_frag6_queue(struct nf_ct_frag6_queue *fq, struct sk_buff *skb,
 191                              const struct frag_hdr *fhdr, int nhoff)
 192 {
 193         struct sk_buff *prev, *next;
 194         int offset, end;
 195
 196         if (fq->q.last_in & INET_FRAG_COMPLETE) {
 197                 pr_debug("Already completed\n");
 198                 goto err;
 199         }
 200
 201         offset = ntohs(fhdr->frag_off) & ~0x7;
 202         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 203                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 204
 205         if ((unsigned int)end > IPV6_MAXPLEN) {
 206                 pr_debug("offset is too large.\n");
 207                 return -1;
 208         }
 209
 210         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 211                 const unsigned char *nh = skb_network_header(skb);
 212                 skb->csum = csum_sub(skb->csum,
 213                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 214                                                   0));
 215         }
 216
 217         /* Is this the final fragment? */
 218         if (!(fhdr->frag_off & htons(IP6_MF))) {
 219                 /* If we already have some bits beyond end
 220                  * or have different end, the segment is corrupted.
 221                  */
 222                 if (end < fq->q.len ||
 223                     ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len)) {
 224                         pr_debug("already received last fragment\n");
 225                         goto err;
 226                 }
 227                 fq->q.last_in |= INET_FRAG_LAST_IN;
 228                 fq->q.len = end;
 229         } else {
 230                 /* Check if the fragment is rounded to 8 bytes.
 231                  * Required by the RFC.
 232                  */
 233                 if (end & 0x7) {
 234                         /* RFC2460 says always send parameter problem in
 235                          * this case. -DaveM
 236                          */
 237                         pr_debug("end of fragment not rounded to 8 bytes.\n");
 238                         return -1;
 239                 }
 240                 if (end > fq->q.len) {
 241                         /* Some bits beyond end -> corruption. */
 242                         if (fq->q.last_in & INET_FRAG_LAST_IN) {
 243                                 pr_debug("last packet already reached.\n");
 244                                 goto err;
 245                         }
 246                         fq->q.len = end;
 247                 }
 248         }
 249
 250         if (end == offset)
 251                 goto err;
 252
 253         /* Point into the IP datagram 'data' part. */
 254         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) {
 255                 pr_debug("queue: message is too short.\n");
 256                 goto err;
 257         }
 258         if (pskb_trim_rcsum(skb, end - offset)) {
 259                 pr_debug("Can't trim\n");
 260                 goto err;
 261         }
 262
 263         /* Find out which fragments are in front and at the back of us
 264          * in the chain of fragments so far.  We must know where to put
 265          * this fragment, right?
 266          */
 267         prev = fq->q.fragments_tail;
 268         if (!prev || NFCT_FRAG6_CB(prev)->offset < offset) {
 269                 next = NULL;
 270                 goto found;
 271         }
 272         prev = NULL;
 273         for (next = fq->q.fragments; next != NULL; next = next->next) {
 274                 if (NFCT_FRAG6_CB(next)->offset >= offset)
 275                         break;  /* bingo! */
 276                 prev = next;
 277         }
 278
 279 found:
 280         /* RFC5722, Section 4:
 281          *                                  When reassembling an IPv6 datagram, if
 282          *   one or more its constituent fragments is determined to be an
 283          *   overlapping fragment, the entire datagram (and any constituent
 284          *   fragments, including those not yet received) MUST be silently
 285          *   discarded.
 286          */
 287
 288         /* Check for overlap with preceding fragment. */
 289         if (prev &&
 290             (NFCT_FRAG6_CB(prev)->offset + prev->len) > offset)
 291                 goto discard_fq;
 292
 293         /* Look for overlap with succeeding segment. */
 294         if (next && NFCT_FRAG6_CB(next)->offset < end)
 295                 goto discard_fq;
 296
 297         NFCT_FRAG6_CB(skb)->offset = offset;
 298
 299         /* Insert this fragment in the chain of fragments. */
 300         skb->next = next;
 301         if (!next)
 302                 fq->q.fragments_tail = skb;
 303         if (prev)
 304                 prev->next = skb;
 305         else
 306                 fq->q.fragments = skb;
 307
 308         skb->dev = NULL;
 309         fq->q.stamp = skb->tstamp;
 310         fq->q.meat += skb->len;
 311         atomic_add(skb->truesize, &nf_init_frags.mem);
 312
 313         /* The first fragment.
 314          * nhoffset is obtained from the first fragment, of course.
 315          */
 316         if (offset == 0) {
 317                 fq->nhoffset = nhoff;
 318                 fq->q.last_in |= INET_FRAG_FIRST_IN;
 319         }
 320         write_lock(&nf_frags.lock);
 321         list_move_tail(&fq->q.lru_list, &nf_init_frags.lru_list);
 322         write_unlock(&nf_frags.lock);
 323         return 0;
 324
 325 discard_fq:
 326         fq_kill(fq);
 327 err:
 328         return -1;
 329 }
 330
 331 /*
 332  *      Check if this packet is complete.
 333  *      Returns NULL on failure by any reason, and pointer
 334  *      to current nexthdr field in reassembled frame.
 335  *
 336  *      It is called with locked fq, and caller must check that
 337  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 338  *      the last and the first frames arrived and all the bits are here.
 339  */
 340 static struct sk_buff *
 341 nf_ct_frag6_reasm(struct nf_ct_frag6_queue *fq, struct net_device *dev)
 342 {
 343         struct sk_buff *fp, *op, *head = fq->q.fragments;
 344         int    payload_len;
 345
 346         fq_kill(fq);
 347
 348         WARN_ON(head == NULL);
 349         WARN_ON(NFCT_FRAG6_CB(head)->offset != 0);
 350
 351         /* Unfragmented part is taken from the first segment. */
 352         payload_len = ((head->data - skb_network_header(head)) -
 353                        sizeof(struct ipv6hdr) + fq->q.len -
 354                        sizeof(struct frag_hdr));
 355         if (payload_len > IPV6_MAXPLEN) {
 356                 pr_debug("payload len is too large.\n");
 357                 goto out_oversize;
 358         }
 359
 360         /* Head of list must not be cloned. */
 361         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) {
 362                 pr_debug("skb is cloned but can't expand head");
 363                 goto out_oom;
 364         }
 365
 366         /* If the first fragment is fragmented itself, we split
 367          * it to two chunks: the first with data and paged part
 368          * and the second, holding only fragments. */
 369         if (skb_has_frag_list(head)) {
 370                 struct sk_buff *clone;
 371                 int i, plen = 0;
 372
 373                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) {
 374                         pr_debug("Can't alloc skb\n");
 375                         goto out_oom;
 376                 }
 377                 clone->next = head->next;
 378                 head->next = clone;
 379                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 380                 skb_frag_list_init(head);
 381                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 382                         plen += skb_shinfo(head)->frags[i].size;
 383                 clone->len = clone->data_len = head->data_len - plen;
 384                 head->data_len -= clone->len;
 385                 head->len -= clone->len;
 386                 clone->csum = 0;
 387                 clone->ip_summed = head->ip_summed;
 388
 389                 NFCT_FRAG6_CB(clone)->orig = NULL;
 390                 atomic_add(clone->truesize, &nf_init_frags.mem);
 391         }
 392
 393         /* We have to remove fragment header from datagram and to relocate
 394          * header in order to calculate ICV correctly. */
 395         skb_network_header(head)[fq->nhoffset] = skb_transport_header(head)[0];
 396         memmove(head->head + sizeof(struct frag_hdr), head->head,
 397                 (head->data - head->head) - sizeof(struct frag_hdr));
 398         head->mac_header += sizeof(struct frag_hdr);
 399         head->network_header += sizeof(struct frag_hdr);
 400
 401         skb_shinfo(head)->frag_list = head->next;
 402         skb_reset_transport_header(head);
 403         skb_push(head, head->data - skb_network_header(head));
 404
 405         for (fp=head->next; fp; fp = fp->next) {
 406                 head->data_len += fp->len;
 407                 head->len += fp->len;
 408                 if (head->ip_summed != fp->ip_summed)
 409                         head->ip_summed = CHECKSUM_NONE;
 410                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 411                         head->csum = csum_add(head->csum, fp->csum);
 412                 head->truesize += fp->truesize;
 413         }
 414         atomic_sub(head->truesize, &nf_init_frags.mem);
 415
 416         head->next = NULL;
 417         head->dev = dev;
 418         head->tstamp = fq->q.stamp;
 419         ipv6_hdr(head)->payload_len = htons(payload_len);
 420
 421         /* Yes, and fold redundant checksum back. 8) */
 422         if (head->ip_summed == CHECKSUM_COMPLETE)
 423                 head->csum = csum_partial(skb_network_header(head),
 424                                           skb_network_header_len(head),
 425                                           head->csum);
 426
 427         fq->q.fragments = NULL;
 428         fq->q.fragments_tail = NULL;
 429
 430         /* all original skbs are linked into the NFCT_FRAG6_CB(head).orig */
 431         fp = skb_shinfo(head)->frag_list;
 432         if (fp && NFCT_FRAG6_CB(fp)->orig == NULL)
 433                 /* at above code, head skb is divided into two skbs. */
 434                 fp = fp->next;
 435
 436         op = NFCT_FRAG6_CB(head)->orig;
 437         for (; fp; fp = fp->next) {
 438                 struct sk_buff *orig = NFCT_FRAG6_CB(fp)->orig;
 439
 440                 op->next = orig;
 441                 op = orig;
 442                 NFCT_FRAG6_CB(fp)->orig = NULL;
 443         }
 444
 445         return head;
 446
 447 out_oversize:
 448         if (net_ratelimit())
 449                 printk(KERN_DEBUG "nf_ct_frag6_reasm: payload len = %d\n", payload_len);
 450         goto out_fail;
 451 out_oom:
 452         if (net_ratelimit())
 453                 printk(KERN_DEBUG "nf_ct_frag6_reasm: no memory for reassembly\n");
 454 out_fail:
 455         return NULL;
 456 }
 457
 458 /*
 459  * find the header just before Fragment Header.
 460  *
 461  * if success return 0 and set ...
 462  * (*prevhdrp): the value of "Next Header Field" in the header
 463  *              just before Fragment Header.
 464  * (*prevhoff): the offset of "Next Header Field" in the header
 465  *              just before Fragment Header.
 466  * (*fhoff)   : the offset of Fragment Header.
 467  *
 468  * Based on ipv6_skip_hdr() in net/ipv6/exthdr.c
 469  *
 470  */
 471 static int
 472 find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff)
 473 {
 474         u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 475         const int netoff = skb_network_offset(skb);
 476         u8 prev_nhoff = netoff + offsetof(struct ipv6hdr, nexthdr);
 477         int start = netoff + sizeof(struct ipv6hdr);
 478         int len = skb->len - start;
 479         u8 prevhdr = NEXTHDR_IPV6;
 480
 481         while (nexthdr != NEXTHDR_FRAGMENT) {
 482                 struct ipv6_opt_hdr hdr;
 483                 int hdrlen;
 484
 485                 if (!ipv6_ext_hdr(nexthdr)) {
 486                         return -1;
 487                 }
 488                 if (nexthdr == NEXTHDR_NONE) {
 489                         pr_debug("next header is none\n");
 490                         return -1;
 491                 }
 492                 if (len < (int)sizeof(struct ipv6_opt_hdr)) {
 493                         pr_debug("too short\n");
 494                         return -1;
 495                 }
 496                 if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
 497                         BUG();
 498                 if (nexthdr == NEXTHDR_AUTH)
 499                         hdrlen = (hdr.hdrlen+2)<<2;
 500                 else
 501                         hdrlen = ipv6_optlen(&hdr);
 502
 503                 prevhdr = nexthdr;
 504                 prev_nhoff = start;
 505
 506                 nexthdr = hdr.nexthdr;
 507                 len -= hdrlen;
 508                 start += hdrlen;
 509         }
 510
 511         if (len < 0)
 512                 return -1;
 513
 514         *prevhdrp = prevhdr;
 515         *prevhoff = prev_nhoff;
 516         *fhoff = start;
 517
 518         return 0;
 519 }
 520
 521 struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user)
 522 {
 523         struct sk_buff *clone;
 524         struct net_device *dev = skb->dev;
 525         struct frag_hdr *fhdr;
 526         struct nf_ct_frag6_queue *fq;
 527         struct ipv6hdr *hdr;
 528         int fhoff, nhoff;
 529         u8 prevhdr;
 530         struct sk_buff *ret_skb = NULL;
 531
 532         /* Jumbo payload inhibits frag. header */
 533         if (ipv6_hdr(skb)->payload_len == 0) {
 534                 pr_debug("payload len = 0\n");
 535                 return skb;
 536         }
 537
 538         if (find_prev_fhdr(skb, &prevhdr, &nhoff, &fhoff) < 0)
 539                 return skb;
 540
 541         clone = skb_clone(skb, GFP_ATOMIC);
 542         if (clone == NULL) {
 543                 pr_debug("Can't clone skb\n");
 544                 return skb;
 545         }
 546
 547         NFCT_FRAG6_CB(clone)->orig = skb;
 548
 549         if (!pskb_may_pull(clone, fhoff + sizeof(*fhdr))) {
 550                 pr_debug("message is too short.\n");
 551                 goto ret_orig;
 552         }
 553
 554         skb_set_transport_header(clone, fhoff);
 555         hdr = ipv6_hdr(clone);
 556         fhdr = (struct frag_hdr *)skb_transport_header(clone);
 557
 558         if (atomic_read(&nf_init_frags.mem) > nf_init_frags.high_thresh)
 559                 nf_ct_frag6_evictor();
 560
 561         fq = fq_find(fhdr->identification, user, &hdr->saddr, &hdr->daddr);
 562         if (fq == NULL) {
 563                 pr_debug("Can't find and can't create new queue\n");
 564                 goto ret_orig;
 565         }
 566
 567         spin_lock_bh(&fq->q.lock);
 568
 569         if (nf_ct_frag6_queue(fq, clone, fhdr, nhoff) < 0) {
 570                 spin_unlock_bh(&fq->q.lock);
 571                 pr_debug("Can't insert skb to queue\n");
 572                 fq_put(fq);
 573                 goto ret_orig;
 574         }
 575
 576         if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 577             fq->q.meat == fq->q.len) {
 578                 ret_skb = nf_ct_frag6_reasm(fq, dev);
 579                 if (ret_skb == NULL)
 580                         pr_debug("Can't reassemble fragmented packets\n");
 581         }
 582         spin_unlock_bh(&fq->q.lock);
 583
 584         fq_put(fq);
 585         return ret_skb;
 586
 587 ret_orig:
 588         kfree_skb(clone);
 589         return skb;
 590 }
 591
 592 void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
 593                         struct net_device *in, struct net_device *out,
 594                         int (*okfn)(struct sk_buff *))
 595 {
 596         struct sk_buff *s, *s2;
 597
 598         for (s = NFCT_FRAG6_CB(skb)->orig; s;) {
 599                 nf_conntrack_put_reasm(s->nfct_reasm);
 600                 nf_conntrack_get_reasm(skb);
 601                 s->nfct_reasm = skb;
 602
 603                 s2 = s->next;
 604                 s->next = NULL;
 605
 606                 NF_HOOK_THRESH(NFPROTO_IPV6, hooknum, s, in, out, okfn,
 607                                NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
 608                 s = s2;
 609         }
 610         nf_conntrack_put_reasm(skb);
 611 }
 612
 613 int nf_ct_frag6_init(void)
 614 {
 615         nf_frags.hashfn = nf_hashfn;
 616         nf_frags.constructor = ip6_frag_init;
 617         nf_frags.destructor = NULL;
 618         nf_frags.skb_free = nf_skb_free;
 619         nf_frags.qsize = sizeof(struct nf_ct_frag6_queue);
 620         nf_frags.match = ip6_frag_match;
 621         nf_frags.frag_expire = nf_ct_frag6_expire;
 622         nf_frags.secret_interval = 10 * 60 * HZ;
 623         nf_init_frags.timeout = IPV6_FRAG_TIMEOUT;
 624         nf_init_frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
 625         nf_init_frags.low_thresh = IPV6_FRAG_LOW_THRESH;
 626         inet_frags_init_net(&nf_init_frags);
 627         inet_frags_init(&nf_frags);
 628
 629 #ifdef CONFIG_SYSCTL
 630         nf_ct_frag6_sysctl_header = register_sysctl_paths(nf_net_netfilter_sysctl_path,
 631                                                           nf_ct_frag6_sysctl_table);
 632         if (!nf_ct_frag6_sysctl_header) {
 633                 inet_frags_fini(&nf_frags);
 634                 return -ENOMEM;
 635         }
 636 #endif
 637
 638         return 0;
 639 }
 640
 641 void nf_ct_frag6_cleanup(void)
 642 {
 643 #ifdef CONFIG_SYSCTL
 644         unregister_sysctl_table(nf_ct_frag6_sysctl_header);
 645         nf_ct_frag6_sysctl_header = NULL;
 646 #endif
 647         inet_frags_fini(&nf_frags);
 648
 649         nf_init_frags.low_thresh = 0;
 650         nf_ct_frag6_evictor();
 651 }