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 static const char nf_frags_cache_name[] = "nf-frags";
  54
  55 struct nf_ct_frag6_skb_cb
  56 {
  57         struct inet6_skb_parm   h;
  58         int                     offset;
  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 int zero;
  67
  68 static struct ctl_table nf_ct_frag6_sysctl_table[] = {
  69         {
  70                 .procname       = "nf_conntrack_frag6_timeout",
  71                 .data           = &init_net.nf_frag.frags.timeout,
  72                 .maxlen         = sizeof(unsigned int),
  73                 .mode           = 0644,
  74                 .proc_handler   = proc_dointvec_jiffies,
  75         },
  76         {
  77                 .procname       = "nf_conntrack_frag6_low_thresh",
  78                 .data           = &init_net.nf_frag.frags.low_thresh,
  79                 .maxlen         = sizeof(unsigned int),
  80                 .mode           = 0644,
  81                 .proc_handler   = proc_dointvec_minmax,
  82                 .extra1         = &zero,
  83                 .extra2         = &init_net.nf_frag.frags.high_thresh
  84         },
  85         {
  86                 .procname       = "nf_conntrack_frag6_high_thresh",
  87                 .data           = &init_net.nf_frag.frags.high_thresh,
  88                 .maxlen         = sizeof(unsigned int),
  89                 .mode           = 0644,
  90                 .proc_handler   = proc_dointvec_minmax,
  91                 .extra1         = &init_net.nf_frag.frags.low_thresh
  92         },
  93         { }
  94 };
  95
  96 static int nf_ct_frag6_sysctl_register(struct net *net)
  97 {
  98         struct ctl_table *table;
  99         struct ctl_table_header *hdr;
 100
 101         table = nf_ct_frag6_sysctl_table;
 102         if (!net_eq(net, &init_net)) {
 103                 table = kmemdup(table, sizeof(nf_ct_frag6_sysctl_table),
 104                                 GFP_KERNEL);
 105                 if (table == NULL)
 106                         goto err_alloc;
 107
 108                 table[0].data = &net->nf_frag.frags.timeout;
 109                 table[1].data = &net->nf_frag.frags.low_thresh;
 110                 table[1].extra2 = &net->nf_frag.frags.high_thresh;
 111                 table[2].data = &net->nf_frag.frags.high_thresh;
 112                 table[2].extra1 = &net->nf_frag.frags.low_thresh;
 113                 table[2].extra2 = &init_net.nf_frag.frags.high_thresh;
 114         }
 115
 116         hdr = register_net_sysctl(net, "net/netfilter", table);
 117         if (hdr == NULL)
 118                 goto err_reg;
 119
 120         net->nf_frag.sysctl.frags_hdr = hdr;
 121         return 0;
 122
 123 err_reg:
 124         if (!net_eq(net, &init_net))
 125                 kfree(table);
 126 err_alloc:
 127         return -ENOMEM;
 128 }
 129
 130 static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
 131 {
 132         struct ctl_table *table;
 133
 134         table = net->nf_frag.sysctl.frags_hdr->ctl_table_arg;
 135         unregister_net_sysctl_table(net->nf_frag.sysctl.frags_hdr);
 136         if (!net_eq(net, &init_net))
 137                 kfree(table);
 138 }
 139
 140 #else
 141 static int nf_ct_frag6_sysctl_register(struct net *net)
 142 {
 143         return 0;
 144 }
 145 static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
 146 {
 147 }
 148 #endif
 149
 150 static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
 151 {
 152         return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
 153 }
 154
 155 static void nf_ct_frag6_expire(struct timer_list *t)
 156 {
 157         struct inet_frag_queue *frag = from_timer(frag, t, timer);
 158         struct frag_queue *fq;
 159         struct net *net;
 160
 161         fq = container_of(frag, struct frag_queue, q);
 162         net = container_of(fq->q.net, struct net, nf_frag.frags);
 163
 164         ip6_expire_frag_queue(net, fq);
 165 }
 166
 167 /* Creation primitives. */
 168 static struct frag_queue *fq_find(struct net *net, __be32 id, u32 user,
 169                                   const struct ipv6hdr *hdr, int iif)
 170 {
 171         struct frag_v6_compare_key key = {
 172                 .id = id,
 173                 .saddr = hdr->saddr,
 174                 .daddr = hdr->daddr,
 175                 .user = user,
 176                 .iif = iif,
 177         };
 178         struct inet_frag_queue *q;
 179
 180         q = inet_frag_find(&net->nf_frag.frags, &key);
 181         if (!q)
 182                 return NULL;
 183
 184         return container_of(q, struct frag_queue, q);
 185 }
 186
 187
 188 static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb,
 189                              const struct frag_hdr *fhdr, int nhoff)
 190 {
 191         struct sk_buff *prev, *next;
 192         unsigned int payload_len;
 193         int offset, end;
 194         u8 ecn;
 195
 196         if (fq->q.flags & INET_FRAG_COMPLETE) {
 197                 pr_debug("Already completed\n");
 198                 goto err;
 199         }
 200
 201         payload_len = ntohs(ipv6_hdr(skb)->payload_len);
 202
 203         offset = ntohs(fhdr->frag_off) & ~0x7;
 204         end = offset + (payload_len -
 205                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 206
 207         if ((unsigned int)end > IPV6_MAXPLEN) {
 208                 pr_debug("offset is too large.\n");
 209                 return -EINVAL;
 210         }
 211
 212         ecn = ip6_frag_ecn(ipv6_hdr(skb));
 213
 214         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 215                 const unsigned char *nh = skb_network_header(skb);
 216                 skb->csum = csum_sub(skb->csum,
 217                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 218                                                   0));
 219         }
 220
 221         /* Is this the final fragment? */
 222         if (!(fhdr->frag_off & htons(IP6_MF))) {
 223                 /* If we already have some bits beyond end
 224                  * or have different end, the segment is corrupted.
 225                  */
 226                 if (end < fq->q.len ||
 227                     ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len)) {
 228                         pr_debug("already received last fragment\n");
 229                         goto err;
 230                 }
 231                 fq->q.flags |= INET_FRAG_LAST_IN;
 232                 fq->q.len = end;
 233         } else {
 234                 /* Check if the fragment is rounded to 8 bytes.
 235                  * Required by the RFC.
 236                  */
 237                 if (end & 0x7) {
 238                         /* RFC2460 says always send parameter problem in
 239                          * this case. -DaveM
 240                          */
 241                         pr_debug("end of fragment not rounded to 8 bytes.\n");
 242                         inet_frag_kill(&fq->q);
 243                         return -EPROTO;
 244                 }
 245                 if (end > fq->q.len) {
 246                         /* Some bits beyond end -> corruption. */
 247                         if (fq->q.flags & INET_FRAG_LAST_IN) {
 248                                 pr_debug("last packet already reached.\n");
 249                                 goto err;
 250                         }
 251                         fq->q.len = end;
 252                 }
 253         }
 254
 255         if (end == offset)
 256                 goto err;
 257
 258         /* Point into the IP datagram 'data' part. */
 259         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) {
 260                 pr_debug("queue: message is too short.\n");
 261                 goto err;
 262         }
 263         if (pskb_trim_rcsum(skb, end - offset)) {
 264                 pr_debug("Can't trim\n");
 265                 goto err;
 266         }
 267
 268         /* Find out which fragments are in front and at the back of us
 269          * in the chain of fragments so far.  We must know where to put
 270          * this fragment, right?
 271          */
 272         prev = fq->q.fragments_tail;
 273         if (!prev || NFCT_FRAG6_CB(prev)->offset < offset) {
 274                 next = NULL;
 275                 goto found;
 276         }
 277         prev = NULL;
 278         for (next = fq->q.fragments; next != NULL; next = next->next) {
 279                 if (NFCT_FRAG6_CB(next)->offset >= offset)
 280                         break;  /* bingo! */
 281                 prev = next;
 282         }
 283
 284 found:
 285         /* RFC5722, Section 4:
 286          *                                  When reassembling an IPv6 datagram, if
 287          *   one or more its constituent fragments is determined to be an
 288          *   overlapping fragment, the entire datagram (and any constituent
 289          *   fragments, including those not yet received) MUST be silently
 290          *   discarded.
 291          */
 292
 293         /* Check for overlap with preceding fragment. */
 294         if (prev &&
 295             (NFCT_FRAG6_CB(prev)->offset + prev->len) > offset)
 296                 goto discard_fq;
 297
 298         /* Look for overlap with succeeding segment. */
 299         if (next && NFCT_FRAG6_CB(next)->offset < end)
 300                 goto discard_fq;
 301
 302         NFCT_FRAG6_CB(skb)->offset = offset;
 303
 304         /* Insert this fragment in the chain of fragments. */
 305         skb->next = next;
 306         if (!next)
 307                 fq->q.fragments_tail = skb;
 308         if (prev)
 309                 prev->next = skb;
 310         else
 311                 fq->q.fragments = skb;
 312
 313         if (skb->dev) {
 314                 fq->iif = skb->dev->ifindex;
 315                 skb->dev = NULL;
 316         }
 317         fq->q.stamp = skb->tstamp;
 318         fq->q.meat += skb->len;
 319         fq->ecn |= ecn;
 320         if (payload_len > fq->q.max_size)
 321                 fq->q.max_size = payload_len;
 322         add_frag_mem_limit(fq->q.net, skb->truesize);
 323
 324         /* The first fragment.
 325          * nhoffset is obtained from the first fragment, of course.
 326          */
 327         if (offset == 0) {
 328                 fq->nhoffset = nhoff;
 329                 fq->q.flags |= INET_FRAG_FIRST_IN;
 330         }
 331
 332         return 0;
 333
 334 discard_fq:
 335         inet_frag_kill(&fq->q);
 336 err:
 337         return -EINVAL;
 338 }
 339
 340 /*
 341  *      Check if this packet is complete.
 342  *
 343  *      It is called with locked fq, and caller must check that
 344  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 345  *      the last and the first frames arrived and all the bits are here.
 346  *
 347  *      returns true if *prev skb has been transformed into the reassembled
 348  *      skb, false otherwise.
 349  */
 350 static bool
 351 nf_ct_frag6_reasm(struct frag_queue *fq, struct sk_buff *prev,  struct net_device *dev)
 352 {
 353         struct sk_buff *fp, *head = fq->q.fragments;
 354         int    payload_len;
 355         u8 ecn;
 356
 357         inet_frag_kill(&fq->q);
 358
 359         WARN_ON(head == NULL);
 360         WARN_ON(NFCT_FRAG6_CB(head)->offset != 0);
 361
 362         ecn = ip_frag_ecn_table[fq->ecn];
 363         if (unlikely(ecn == 0xff))
 364                 return false;
 365
 366         /* Unfragmented part is taken from the first segment. */
 367         payload_len = ((head->data - skb_network_header(head)) -
 368                        sizeof(struct ipv6hdr) + fq->q.len -
 369                        sizeof(struct frag_hdr));
 370         if (payload_len > IPV6_MAXPLEN) {
 371                 net_dbg_ratelimited("nf_ct_frag6_reasm: payload len = %d\n",
 372                                     payload_len);
 373                 return false;
 374         }
 375
 376         /* Head of list must not be cloned. */
 377         if (skb_unclone(head, GFP_ATOMIC))
 378                 return false;
 379
 380         /* If the first fragment is fragmented itself, we split
 381          * it to two chunks: the first with data and paged part
 382          * and the second, holding only fragments. */
 383         if (skb_has_frag_list(head)) {
 384                 struct sk_buff *clone;
 385                 int i, plen = 0;
 386
 387                 clone = alloc_skb(0, GFP_ATOMIC);
 388                 if (clone == NULL)
 389                         return false;
 390
 391                 clone->next = head->next;
 392                 head->next = clone;
 393                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 394                 skb_frag_list_init(head);
 395                 for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
 396                         plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
 397                 clone->len = clone->data_len = head->data_len - plen;
 398                 head->data_len -= clone->len;
 399                 head->len -= clone->len;
 400                 clone->csum = 0;
 401                 clone->ip_summed = head->ip_summed;
 402
 403                 add_frag_mem_limit(fq->q.net, clone->truesize);
 404         }
 405
 406         /* morph head into last received skb: prev.
 407          *
 408          * This allows callers of ipv6 conntrack defrag to continue
 409          * to use the last skb(frag) passed into the reasm engine.
 410          * The last skb frag 'silently' turns into the full reassembled skb.
 411          *
 412          * Since prev is also part of q->fragments we have to clone it first.
 413          */
 414         if (head != prev) {
 415                 struct sk_buff *iter;
 416
 417                 fp = skb_clone(prev, GFP_ATOMIC);
 418                 if (!fp)
 419                         return false;
 420
 421                 fp->next = prev->next;
 422
 423                 iter = head;
 424                 while (iter) {
 425                         if (iter->next == prev) {
 426                                 iter->next = fp;
 427                                 break;
 428                         }
 429                         iter = iter->next;
 430                 }
 431
 432                 skb_morph(prev, head);
 433                 prev->next = head->next;
 434                 consume_skb(head);
 435                 head = prev;
 436         }
 437
 438         /* We have to remove fragment header from datagram and to relocate
 439          * header in order to calculate ICV correctly. */
 440         skb_network_header(head)[fq->nhoffset] = skb_transport_header(head)[0];
 441         memmove(head->head + sizeof(struct frag_hdr), head->head,
 442                 (head->data - head->head) - sizeof(struct frag_hdr));
 443         head->mac_header += sizeof(struct frag_hdr);
 444         head->network_header += sizeof(struct frag_hdr);
 445
 446         skb_shinfo(head)->frag_list = head->next;
 447         skb_reset_transport_header(head);
 448         skb_push(head, head->data - skb_network_header(head));
 449
 450         for (fp = head->next; fp; fp = fp->next) {
 451                 head->data_len += fp->len;
 452                 head->len += fp->len;
 453                 if (head->ip_summed != fp->ip_summed)
 454                         head->ip_summed = CHECKSUM_NONE;
 455                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 456                         head->csum = csum_add(head->csum, fp->csum);
 457                 head->truesize += fp->truesize;
 458         }
 459         sub_frag_mem_limit(fq->q.net, head->truesize);
 460
 461         head->ignore_df = 1;
 462         head->next = NULL;
 463         head->dev = dev;
 464         head->tstamp = fq->q.stamp;
 465         ipv6_hdr(head)->payload_len = htons(payload_len);
 466         ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
 467         IP6CB(head)->frag_max_size = sizeof(struct ipv6hdr) + fq->q.max_size;
 468
 469         /* Yes, and fold redundant checksum back. 8) */
 470         if (head->ip_summed == CHECKSUM_COMPLETE)
 471                 head->csum = csum_partial(skb_network_header(head),
 472                                           skb_network_header_len(head),
 473                                           head->csum);
 474
 475         fq->q.fragments = NULL;
 476         fq->q.fragments_tail = NULL;
 477
 478         return true;
 479 }
 480
 481 /*
 482  * find the header just before Fragment Header.
 483  *
 484  * if success return 0 and set ...
 485  * (*prevhdrp): the value of "Next Header Field" in the header
 486  *              just before Fragment Header.
 487  * (*prevhoff): the offset of "Next Header Field" in the header
 488  *              just before Fragment Header.
 489  * (*fhoff)   : the offset of Fragment Header.
 490  *
 491  * Based on ipv6_skip_hdr() in net/ipv6/exthdr.c
 492  *
 493  */
 494 static int
 495 find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff)
 496 {
 497         u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 498         const int netoff = skb_network_offset(skb);
 499         u8 prev_nhoff = netoff + offsetof(struct ipv6hdr, nexthdr);
 500         int start = netoff + sizeof(struct ipv6hdr);
 501         int len = skb->len - start;
 502         u8 prevhdr = NEXTHDR_IPV6;
 503
 504         while (nexthdr != NEXTHDR_FRAGMENT) {
 505                 struct ipv6_opt_hdr hdr;
 506                 int hdrlen;
 507
 508                 if (!ipv6_ext_hdr(nexthdr)) {
 509                         return -1;
 510                 }
 511                 if (nexthdr == NEXTHDR_NONE) {
 512                         pr_debug("next header is none\n");
 513                         return -1;
 514                 }
 515                 if (len < (int)sizeof(struct ipv6_opt_hdr)) {
 516                         pr_debug("too short\n");
 517                         return -1;
 518                 }
 519                 if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
 520                         BUG();
 521                 if (nexthdr == NEXTHDR_AUTH)
 522                         hdrlen = (hdr.hdrlen+2)<<2;
 523                 else
 524                         hdrlen = ipv6_optlen(&hdr);
 525
 526                 prevhdr = nexthdr;
 527                 prev_nhoff = start;
 528
 529                 nexthdr = hdr.nexthdr;
 530                 len -= hdrlen;
 531                 start += hdrlen;
 532         }
 533
 534         if (len < 0)
 535                 return -1;
 536
 537         *prevhdrp = prevhdr;
 538         *prevhoff = prev_nhoff;
 539         *fhoff = start;
 540
 541         return 0;
 542 }
 543
 544 int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user)
 545 {
 546         u16 savethdr = skb->transport_header;
 547         struct net_device *dev = skb->dev;
 548         int fhoff, nhoff, ret;
 549         struct frag_hdr *fhdr;
 550         struct frag_queue *fq;
 551         struct ipv6hdr *hdr;
 552         u8 prevhdr;
 553
 554         /* Jumbo payload inhibits frag. header */
 555         if (ipv6_hdr(skb)->payload_len == 0) {
 556                 pr_debug("payload len = 0\n");
 557                 return 0;
 558         }
 559
 560         if (find_prev_fhdr(skb, &prevhdr, &nhoff, &fhoff) < 0)
 561                 return 0;
 562
 563         if (!pskb_may_pull(skb, fhoff + sizeof(*fhdr)))
 564                 return -ENOMEM;
 565
 566         skb_set_transport_header(skb, fhoff);
 567         hdr = ipv6_hdr(skb);
 568         fhdr = (struct frag_hdr *)skb_transport_header(skb);
 569
 570         skb_orphan(skb);
 571         fq = fq_find(net, fhdr->identification, user, hdr,
 572                      skb->dev ? skb->dev->ifindex : 0);
 573         if (fq == NULL) {
 574                 pr_debug("Can't find and can't create new queue\n");
 575                 return -ENOMEM;
 576         }
 577
 578         spin_lock_bh(&fq->q.lock);
 579
 580         ret = nf_ct_frag6_queue(fq, skb, fhdr, nhoff);
 581         if (ret < 0) {
 582                 if (ret == -EPROTO) {
 583                         skb->transport_header = savethdr;
 584                         ret = 0;
 585                 }
 586                 goto out_unlock;
 587         }
 588
 589         /* after queue has assumed skb ownership, only 0 or -EINPROGRESS
 590          * must be returned.
 591          */
 592         ret = -EINPROGRESS;
 593         if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 594             fq->q.meat == fq->q.len &&
 595             nf_ct_frag6_reasm(fq, skb, dev))
 596                 ret = 0;
 597
 598 out_unlock:
 599         spin_unlock_bh(&fq->q.lock);
 600         inet_frag_put(&fq->q);
 601         return ret;
 602 }
 603 EXPORT_SYMBOL_GPL(nf_ct_frag6_gather);
 604
 605 static int nf_ct_net_init(struct net *net)
 606 {
 607         int res;
 608
 609         net->nf_frag.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
 610         net->nf_frag.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
 611         net->nf_frag.frags.timeout = IPV6_FRAG_TIMEOUT;
 612         net->nf_frag.frags.f = &nf_frags;
 613
 614         res = inet_frags_init_net(&net->nf_frag.frags);
 615         if (res < 0)
 616                 return res;
 617         res = nf_ct_frag6_sysctl_register(net);
 618         if (res < 0)
 619                 inet_frags_exit_net(&net->nf_frag.frags);
 620         return res;
 621 }
 622
 623 static void nf_ct_net_exit(struct net *net)
 624 {
 625         nf_ct_frags6_sysctl_unregister(net);
 626         inet_frags_exit_net(&net->nf_frag.frags);
 627 }
 628
 629 static struct pernet_operations nf_ct_net_ops = {
 630         .init = nf_ct_net_init,
 631         .exit = nf_ct_net_exit,
 632 };
 633
 634 int nf_ct_frag6_init(void)
 635 {
 636         int ret = 0;
 637
 638         nf_frags.constructor = ip6_frag_init;
 639         nf_frags.destructor = NULL;
 640         nf_frags.qsize = sizeof(struct frag_queue);
 641         nf_frags.frag_expire = nf_ct_frag6_expire;
 642         nf_frags.frags_cache_name = nf_frags_cache_name;
 643         nf_frags.rhash_params = ip6_rhash_params;
 644         ret = inet_frags_init(&nf_frags);
 645         if (ret)
 646                 goto out;
 647         ret = register_pernet_subsys(&nf_ct_net_ops);
 648         if (ret)
 649                 inet_frags_fini(&nf_frags);
 650
 651 out:
 652         return ret;
 653 }
 654
 655 void nf_ct_frag6_cleanup(void)
 656 {
 657         unregister_pernet_subsys(&nf_ct_net_ops);
 658         inet_frags_fini(&nf_frags);
 659 }