linux/net/ipv6/netfilter/nf_conntrack_reasm.c
<<
>>
Prefs
   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
  53static const char nf_frags_cache_name[] = "nf-frags";
  54
  55struct 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
  63static struct inet_frags nf_frags;
  64
  65#ifdef CONFIG_SYSCTL
  66static int zero;
  67
  68static 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
  96static 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
 123err_reg:
 124        if (!net_eq(net, &init_net))
 125                kfree(table);
 126err_alloc:
 127        return -ENOMEM;
 128}
 129
 130static 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
 141static int nf_ct_frag6_sysctl_register(struct net *net)
 142{
 143        return 0;
 144}
 145static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
 146{
 147}
 148#endif
 149
 150static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
 151{
 152        return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
 153}
 154
 155static unsigned int nf_hash_frag(__be32 id, const struct in6_addr *saddr,
 156                                 const struct in6_addr *daddr)
 157{
 158        net_get_random_once(&nf_frags.rnd, sizeof(nf_frags.rnd));
 159        return jhash_3words(ipv6_addr_hash(saddr), ipv6_addr_hash(daddr),
 160                            (__force u32)id, nf_frags.rnd);
 161}
 162
 163
 164static unsigned int nf_hashfn(const struct inet_frag_queue *q)
 165{
 166        const struct frag_queue *nq;
 167
 168        nq = container_of(q, struct frag_queue, q);
 169        return nf_hash_frag(nq->id, &nq->saddr, &nq->daddr);
 170}
 171
 172static void nf_ct_frag6_expire(unsigned long data)
 173{
 174        struct frag_queue *fq;
 175        struct net *net;
 176
 177        fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 178        net = container_of(fq->q.net, struct net, nf_frag.frags);
 179
 180        ip6_expire_frag_queue(net, fq, &nf_frags);
 181}
 182
 183/* Creation primitives. */
 184static inline struct frag_queue *fq_find(struct net *net, __be32 id,
 185                                         u32 user, struct in6_addr *src,
 186                                         struct in6_addr *dst, int iif, u8 ecn)
 187{
 188        struct inet_frag_queue *q;
 189        struct ip6_create_arg arg;
 190        unsigned int hash;
 191
 192        arg.id = id;
 193        arg.user = user;
 194        arg.src = src;
 195        arg.dst = dst;
 196        arg.iif = iif;
 197        arg.ecn = ecn;
 198
 199        local_bh_disable();
 200        hash = nf_hash_frag(id, src, dst);
 201
 202        q = inet_frag_find(&net->nf_frag.frags, &nf_frags, &arg, hash);
 203        local_bh_enable();
 204        if (IS_ERR_OR_NULL(q)) {
 205                inet_frag_maybe_warn_overflow(q, pr_fmt());
 206                return NULL;
 207        }
 208        return container_of(q, struct frag_queue, q);
 209}
 210
 211
 212static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb,
 213                             const struct frag_hdr *fhdr, int nhoff)
 214{
 215        struct sk_buff *prev, *next;
 216        unsigned int payload_len;
 217        int offset, end;
 218        u8 ecn;
 219
 220        if (fq->q.flags & INET_FRAG_COMPLETE) {
 221                pr_debug("Already completed\n");
 222                goto err;
 223        }
 224
 225        payload_len = ntohs(ipv6_hdr(skb)->payload_len);
 226
 227        offset = ntohs(fhdr->frag_off) & ~0x7;
 228        end = offset + (payload_len -
 229                        ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 230
 231        if ((unsigned int)end > IPV6_MAXPLEN) {
 232                pr_debug("offset is too large.\n");
 233                return -1;
 234        }
 235
 236        ecn = ip6_frag_ecn(ipv6_hdr(skb));
 237
 238        if (skb->ip_summed == CHECKSUM_COMPLETE) {
 239                const unsigned char *nh = skb_network_header(skb);
 240                skb->csum = csum_sub(skb->csum,
 241                                     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 242                                                  0));
 243        }
 244
 245        /* Is this the final fragment? */
 246        if (!(fhdr->frag_off & htons(IP6_MF))) {
 247                /* If we already have some bits beyond end
 248                 * or have different end, the segment is corrupted.
 249                 */
 250                if (end < fq->q.len ||
 251                    ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len)) {
 252                        pr_debug("already received last fragment\n");
 253                        goto err;
 254                }
 255                fq->q.flags |= INET_FRAG_LAST_IN;
 256                fq->q.len = end;
 257        } else {
 258                /* Check if the fragment is rounded to 8 bytes.
 259                 * Required by the RFC.
 260                 */
 261                if (end & 0x7) {
 262                        /* RFC2460 says always send parameter problem in
 263                         * this case. -DaveM
 264                         */
 265                        pr_debug("end of fragment not rounded to 8 bytes.\n");
 266                        return -1;
 267                }
 268                if (end > fq->q.len) {
 269                        /* Some bits beyond end -> corruption. */
 270                        if (fq->q.flags & INET_FRAG_LAST_IN) {
 271                                pr_debug("last packet already reached.\n");
 272                                goto err;
 273                        }
 274                        fq->q.len = end;
 275                }
 276        }
 277
 278        if (end == offset)
 279                goto err;
 280
 281        /* Point into the IP datagram 'data' part. */
 282        if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) {
 283                pr_debug("queue: message is too short.\n");
 284                goto err;
 285        }
 286        if (pskb_trim_rcsum(skb, end - offset)) {
 287                pr_debug("Can't trim\n");
 288                goto err;
 289        }
 290
 291        /* Find out which fragments are in front and at the back of us
 292         * in the chain of fragments so far.  We must know where to put
 293         * this fragment, right?
 294         */
 295        prev = fq->q.fragments_tail;
 296        if (!prev || NFCT_FRAG6_CB(prev)->offset < offset) {
 297                next = NULL;
 298                goto found;
 299        }
 300        prev = NULL;
 301        for (next = fq->q.fragments; next != NULL; next = next->next) {
 302                if (NFCT_FRAG6_CB(next)->offset >= offset)
 303                        break;  /* bingo! */
 304                prev = next;
 305        }
 306
 307found:
 308        /* RFC5722, Section 4:
 309         *                                  When reassembling an IPv6 datagram, if
 310         *   one or more its constituent fragments is determined to be an
 311         *   overlapping fragment, the entire datagram (and any constituent
 312         *   fragments, including those not yet received) MUST be silently
 313         *   discarded.
 314         */
 315
 316        /* Check for overlap with preceding fragment. */
 317        if (prev &&
 318            (NFCT_FRAG6_CB(prev)->offset + prev->len) > offset)
 319                goto discard_fq;
 320
 321        /* Look for overlap with succeeding segment. */
 322        if (next && NFCT_FRAG6_CB(next)->offset < end)
 323                goto discard_fq;
 324
 325        NFCT_FRAG6_CB(skb)->offset = offset;
 326
 327        /* Insert this fragment in the chain of fragments. */
 328        skb->next = next;
 329        if (!next)
 330                fq->q.fragments_tail = skb;
 331        if (prev)
 332                prev->next = skb;
 333        else
 334                fq->q.fragments = skb;
 335
 336        if (skb->dev) {
 337                fq->iif = skb->dev->ifindex;
 338                skb->dev = NULL;
 339        }
 340        fq->q.stamp = skb->tstamp;
 341        fq->q.meat += skb->len;
 342        fq->ecn |= ecn;
 343        if (payload_len > fq->q.max_size)
 344                fq->q.max_size = payload_len;
 345        add_frag_mem_limit(fq->q.net, skb->truesize);
 346
 347        /* The first fragment.
 348         * nhoffset is obtained from the first fragment, of course.
 349         */
 350        if (offset == 0) {
 351                fq->nhoffset = nhoff;
 352                fq->q.flags |= INET_FRAG_FIRST_IN;
 353        }
 354
 355        return 0;
 356
 357discard_fq:
 358        inet_frag_kill(&fq->q, &nf_frags);
 359err:
 360        return -1;
 361}
 362
 363/*
 364 *      Check if this packet is complete.
 365 *
 366 *      It is called with locked fq, and caller must check that
 367 *      queue is eligible for reassembly i.e. it is not COMPLETE,
 368 *      the last and the first frames arrived and all the bits are here.
 369 *
 370 *      returns true if *prev skb has been transformed into the reassembled
 371 *      skb, false otherwise.
 372 */
 373static bool
 374nf_ct_frag6_reasm(struct frag_queue *fq, struct sk_buff *prev,  struct net_device *dev)
 375{
 376        struct sk_buff *fp, *head = fq->q.fragments;
 377        int    payload_len;
 378        u8 ecn;
 379
 380        inet_frag_kill(&fq->q, &nf_frags);
 381
 382        WARN_ON(head == NULL);
 383        WARN_ON(NFCT_FRAG6_CB(head)->offset != 0);
 384
 385        ecn = ip_frag_ecn_table[fq->ecn];
 386        if (unlikely(ecn == 0xff))
 387                return false;
 388
 389        /* Unfragmented part is taken from the first segment. */
 390        payload_len = ((head->data - skb_network_header(head)) -
 391                       sizeof(struct ipv6hdr) + fq->q.len -
 392                       sizeof(struct frag_hdr));
 393        if (payload_len > IPV6_MAXPLEN) {
 394                net_dbg_ratelimited("nf_ct_frag6_reasm: payload len = %d\n",
 395                                    payload_len);
 396                return false;
 397        }
 398
 399        /* Head of list must not be cloned. */
 400        if (skb_unclone(head, GFP_ATOMIC))
 401                return false;
 402
 403        /* If the first fragment is fragmented itself, we split
 404         * it to two chunks: the first with data and paged part
 405         * and the second, holding only fragments. */
 406        if (skb_has_frag_list(head)) {
 407                struct sk_buff *clone;
 408                int i, plen = 0;
 409
 410                clone = alloc_skb(0, GFP_ATOMIC);
 411                if (clone == NULL)
 412                        return false;
 413
 414                clone->next = head->next;
 415                head->next = clone;
 416                skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 417                skb_frag_list_init(head);
 418                for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
 419                        plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
 420                clone->len = clone->data_len = head->data_len - plen;
 421                head->data_len -= clone->len;
 422                head->len -= clone->len;
 423                clone->csum = 0;
 424                clone->ip_summed = head->ip_summed;
 425
 426                add_frag_mem_limit(fq->q.net, clone->truesize);
 427        }
 428
 429        /* morph head into last received skb: prev.
 430         *
 431         * This allows callers of ipv6 conntrack defrag to continue
 432         * to use the last skb(frag) passed into the reasm engine.
 433         * The last skb frag 'silently' turns into the full reassembled skb.
 434         *
 435         * Since prev is also part of q->fragments we have to clone it first.
 436         */
 437        if (head != prev) {
 438                struct sk_buff *iter;
 439
 440                fp = skb_clone(prev, GFP_ATOMIC);
 441                if (!fp)
 442                        return false;
 443
 444                fp->next = prev->next;
 445
 446                iter = head;
 447                while (iter) {
 448                        if (iter->next == prev) {
 449                                iter->next = fp;
 450                                break;
 451                        }
 452                        iter = iter->next;
 453                }
 454
 455                skb_morph(prev, head);
 456                prev->next = head->next;
 457                consume_skb(head);
 458                head = prev;
 459        }
 460
 461        /* We have to remove fragment header from datagram and to relocate
 462         * header in order to calculate ICV correctly. */
 463        skb_network_header(head)[fq->nhoffset] = skb_transport_header(head)[0];
 464        memmove(head->head + sizeof(struct frag_hdr), head->head,
 465                (head->data - head->head) - sizeof(struct frag_hdr));
 466        head->mac_header += sizeof(struct frag_hdr);
 467        head->network_header += sizeof(struct frag_hdr);
 468
 469        skb_shinfo(head)->frag_list = head->next;
 470        skb_reset_transport_header(head);
 471        skb_push(head, head->data - skb_network_header(head));
 472
 473        for (fp = head->next; fp; fp = fp->next) {
 474                head->data_len += fp->len;
 475                head->len += fp->len;
 476                if (head->ip_summed != fp->ip_summed)
 477                        head->ip_summed = CHECKSUM_NONE;
 478                else if (head->ip_summed == CHECKSUM_COMPLETE)
 479                        head->csum = csum_add(head->csum, fp->csum);
 480                head->truesize += fp->truesize;
 481        }
 482        sub_frag_mem_limit(fq->q.net, head->truesize);
 483
 484        head->ignore_df = 1;
 485        head->next = NULL;
 486        head->dev = dev;
 487        head->tstamp = fq->q.stamp;
 488        ipv6_hdr(head)->payload_len = htons(payload_len);
 489        ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
 490        IP6CB(head)->frag_max_size = sizeof(struct ipv6hdr) + fq->q.max_size;
 491
 492        /* Yes, and fold redundant checksum back. 8) */
 493        if (head->ip_summed == CHECKSUM_COMPLETE)
 494                head->csum = csum_partial(skb_network_header(head),
 495                                          skb_network_header_len(head),
 496                                          head->csum);
 497
 498        fq->q.fragments = NULL;
 499        fq->q.fragments_tail = NULL;
 500
 501        return true;
 502}
 503
 504/*
 505 * find the header just before Fragment Header.
 506 *
 507 * if success return 0 and set ...
 508 * (*prevhdrp): the value of "Next Header Field" in the header
 509 *              just before Fragment Header.
 510 * (*prevhoff): the offset of "Next Header Field" in the header
 511 *              just before Fragment Header.
 512 * (*fhoff)   : the offset of Fragment Header.
 513 *
 514 * Based on ipv6_skip_hdr() in net/ipv6/exthdr.c
 515 *
 516 */
 517static int
 518find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff)
 519{
 520        u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 521        const int netoff = skb_network_offset(skb);
 522        u8 prev_nhoff = netoff + offsetof(struct ipv6hdr, nexthdr);
 523        int start = netoff + sizeof(struct ipv6hdr);
 524        int len = skb->len - start;
 525        u8 prevhdr = NEXTHDR_IPV6;
 526
 527        while (nexthdr != NEXTHDR_FRAGMENT) {
 528                struct ipv6_opt_hdr hdr;
 529                int hdrlen;
 530
 531                if (!ipv6_ext_hdr(nexthdr)) {
 532                        return -1;
 533                }
 534                if (nexthdr == NEXTHDR_NONE) {
 535                        pr_debug("next header is none\n");
 536                        return -1;
 537                }
 538                if (len < (int)sizeof(struct ipv6_opt_hdr)) {
 539                        pr_debug("too short\n");
 540                        return -1;
 541                }
 542                if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
 543                        BUG();
 544                if (nexthdr == NEXTHDR_AUTH)
 545                        hdrlen = (hdr.hdrlen+2)<<2;
 546                else
 547                        hdrlen = ipv6_optlen(&hdr);
 548
 549                prevhdr = nexthdr;
 550                prev_nhoff = start;
 551
 552                nexthdr = hdr.nexthdr;
 553                len -= hdrlen;
 554                start += hdrlen;
 555        }
 556
 557        if (len < 0)
 558                return -1;
 559
 560        *prevhdrp = prevhdr;
 561        *prevhoff = prev_nhoff;
 562        *fhoff = start;
 563
 564        return 0;
 565}
 566
 567int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user)
 568{
 569        struct net_device *dev = skb->dev;
 570        int fhoff, nhoff, ret;
 571        struct frag_hdr *fhdr;
 572        struct frag_queue *fq;
 573        struct ipv6hdr *hdr;
 574        u8 prevhdr;
 575
 576        /* Jumbo payload inhibits frag. header */
 577        if (ipv6_hdr(skb)->payload_len == 0) {
 578                pr_debug("payload len = 0\n");
 579                return -EINVAL;
 580        }
 581
 582        if (find_prev_fhdr(skb, &prevhdr, &nhoff, &fhoff) < 0)
 583                return -EINVAL;
 584
 585        if (!pskb_may_pull(skb, fhoff + sizeof(*fhdr)))
 586                return -ENOMEM;
 587
 588        skb_set_transport_header(skb, fhoff);
 589        hdr = ipv6_hdr(skb);
 590        fhdr = (struct frag_hdr *)skb_transport_header(skb);
 591
 592        fq = fq_find(net, fhdr->identification, user, &hdr->saddr, &hdr->daddr,
 593                     skb->dev ? skb->dev->ifindex : 0, ip6_frag_ecn(hdr));
 594        if (fq == NULL) {
 595                pr_debug("Can't find and can't create new queue\n");
 596                return -ENOMEM;
 597        }
 598
 599        spin_lock_bh(&fq->q.lock);
 600
 601        if (nf_ct_frag6_queue(fq, skb, fhdr, nhoff) < 0) {
 602                ret = -EINVAL;
 603                goto out_unlock;
 604        }
 605
 606        /* after queue has assumed skb ownership, only 0 or -EINPROGRESS
 607         * must be returned.
 608         */
 609        ret = -EINPROGRESS;
 610        if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 611            fq->q.meat == fq->q.len &&
 612            nf_ct_frag6_reasm(fq, skb, dev))
 613                ret = 0;
 614
 615out_unlock:
 616        spin_unlock_bh(&fq->q.lock);
 617        inet_frag_put(&fq->q, &nf_frags);
 618        return ret;
 619}
 620EXPORT_SYMBOL_GPL(nf_ct_frag6_gather);
 621
 622static int nf_ct_net_init(struct net *net)
 623{
 624        int res;
 625
 626        net->nf_frag.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
 627        net->nf_frag.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
 628        net->nf_frag.frags.timeout = IPV6_FRAG_TIMEOUT;
 629        res = inet_frags_init_net(&net->nf_frag.frags);
 630        if (res)
 631                return res;
 632        res = nf_ct_frag6_sysctl_register(net);
 633        if (res)
 634                inet_frags_uninit_net(&net->nf_frag.frags);
 635        return res;
 636}
 637
 638static void nf_ct_net_exit(struct net *net)
 639{
 640        nf_ct_frags6_sysctl_unregister(net);
 641        inet_frags_exit_net(&net->nf_frag.frags, &nf_frags);
 642}
 643
 644static struct pernet_operations nf_ct_net_ops = {
 645        .init = nf_ct_net_init,
 646        .exit = nf_ct_net_exit,
 647};
 648
 649int nf_ct_frag6_init(void)
 650{
 651        int ret = 0;
 652
 653        nf_frags.hashfn = nf_hashfn;
 654        nf_frags.constructor = ip6_frag_init;
 655        nf_frags.destructor = NULL;
 656        nf_frags.qsize = sizeof(struct frag_queue);
 657        nf_frags.match = ip6_frag_match;
 658        nf_frags.frag_expire = nf_ct_frag6_expire;
 659        nf_frags.frags_cache_name = nf_frags_cache_name;
 660        ret = inet_frags_init(&nf_frags);
 661        if (ret)
 662                goto out;
 663        ret = register_pernet_subsys(&nf_ct_net_ops);
 664        if (ret)
 665                inet_frags_fini(&nf_frags);
 666
 667out:
 668        return ret;
 669}
 670
 671void nf_ct_frag6_cleanup(void)
 672{
 673        unregister_pernet_subsys(&nf_ct_net_ops);
 674        inet_frags_fini(&nf_frags);
 675}
 676