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
  54 struct nf_ct_frag6_skb_cb
  55 {
  56         struct inet6_skb_parm   h;
  57         int                     offset;
  58         struct sk_buff          *orig;
  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 struct ctl_table nf_ct_frag6_sysctl_table[] = {
  67         {
  68                 .procname       = "nf_conntrack_frag6_timeout",
  69                 .data           = &init_net.nf_frag.frags.timeout,
  70                 .maxlen         = sizeof(unsigned int),
  71                 .mode           = 0644,
  72                 .proc_handler   = proc_dointvec_jiffies,
  73         },
  74         {
  75                 .procname       = "nf_conntrack_frag6_low_thresh",
  76                 .data           = &init_net.nf_frag.frags.low_thresh,
  77                 .maxlen         = sizeof(unsigned int),
  78                 .mode           = 0644,
  79                 .proc_handler   = proc_dointvec,
  80         },
  81         {
  82                 .procname       = "nf_conntrack_frag6_high_thresh",
  83                 .data           = &init_net.nf_frag.frags.high_thresh,
  84                 .maxlen         = sizeof(unsigned int),
  85                 .mode           = 0644,
  86                 .proc_handler   = proc_dointvec,
  87         },
  88         { }
  89 };
  90
  91 static int nf_ct_frag6_sysctl_register(struct net *net)
  92 {
  93         struct ctl_table *table;
  94         struct ctl_table_header *hdr;
  95
  96         table = nf_ct_frag6_sysctl_table;
  97         if (!net_eq(net, &init_net)) {
  98                 table = kmemdup(table, sizeof(nf_ct_frag6_sysctl_table),
  99                                 GFP_KERNEL);
 100                 if (table == NULL)
 101                         goto err_alloc;
 102
 103                 table[0].data = &net->nf_frag.frags.timeout;
 104                 table[1].data = &net->nf_frag.frags.low_thresh;
 105                 table[2].data = &net->nf_frag.frags.high_thresh;
 106         }
 107
 108         hdr = register_net_sysctl(net, "net/netfilter", table);
 109         if (hdr == NULL)
 110                 goto err_reg;
 111
 112         net->nf_frag.sysctl.frags_hdr = hdr;
 113         return 0;
 114
 115 err_reg:
 116         if (!net_eq(net, &init_net))
 117                 kfree(table);
 118 err_alloc:
 119         return -ENOMEM;
 120 }
 121
 122 static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
 123 {
 124         struct ctl_table *table;
 125
 126         table = net->nf_frag.sysctl.frags_hdr->ctl_table_arg;
 127         unregister_net_sysctl_table(net->nf_frag.sysctl.frags_hdr);
 128         if (!net_eq(net, &init_net))
 129                 kfree(table);
 130 }
 131
 132 #else
 133 static int nf_ct_frag6_sysctl_register(struct net *net)
 134 {
 135         return 0;
 136 }
 137 static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
 138 {
 139 }
 140 #endif
 141
 142 static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
 143 {
 144         return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
 145 }
 146
 147 static unsigned int nf_hash_frag(__be32 id, const struct in6_addr *saddr,
 148                                  const struct in6_addr *daddr)
 149 {
 150         u32 c;
 151
 152         net_get_random_once(&nf_frags.rnd, sizeof(nf_frags.rnd));
 153         c = jhash_3words(ipv6_addr_hash(saddr), ipv6_addr_hash(daddr),
 154                          (__force u32)id, nf_frags.rnd);
 155         return c & (INETFRAGS_HASHSZ - 1);
 156 }
 157
 158
 159 static unsigned int nf_hashfn(struct inet_frag_queue *q)
 160 {
 161         const struct frag_queue *nq;
 162
 163         nq = container_of(q, struct frag_queue, q);
 164         return nf_hash_frag(nq->id, &nq->saddr, &nq->daddr);
 165 }
 166
 167 static void nf_skb_free(struct sk_buff *skb)
 168 {
 169         if (NFCT_FRAG6_CB(skb)->orig)
 170                 kfree_skb(NFCT_FRAG6_CB(skb)->orig);
 171 }
 172
 173 static void nf_ct_frag6_expire(unsigned long data)
 174 {
 175         struct frag_queue *fq;
 176         struct net *net;
 177
 178         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 179         net = container_of(fq->q.net, struct net, nf_frag.frags);
 180
 181         ip6_expire_frag_queue(net, fq, &nf_frags);
 182 }
 183
 184 /* Creation primitives. */
 185 static inline struct frag_queue *fq_find(struct net *net, __be32 id,
 186                                          u32 user, struct in6_addr *src,
 187                                          struct in6_addr *dst, u8 ecn)
 188 {
 189         struct inet_frag_queue *q;
 190         struct ip6_create_arg arg;
 191         unsigned int hash;
 192
 193         arg.id = id;
 194         arg.user = user;
 195         arg.src = src;
 196         arg.dst = dst;
 197         arg.ecn = ecn;
 198
 199         read_lock_bh(&nf_frags.lock);
 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
 212 static 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.last_in & 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.last_in & INET_FRAG_LAST_IN) && end != fq->q.len)) {
 252                         pr_debug("already received last fragment\n");
 253                         goto err;
 254                 }
 255                 fq->q.last_in |= 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.last_in & 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
 307 found:
 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, 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.last_in |= INET_FRAG_FIRST_IN;
 353         }
 354
 355         inet_frag_lru_move(&fq->q);
 356         return 0;
 357
 358 discard_fq:
 359         inet_frag_kill(&fq->q, &nf_frags);
 360 err:
 361         return -1;
 362 }
 363
 364 /*
 365  *      Check if this packet is complete.
 366  *      Returns NULL on failure by any reason, and pointer
 367  *      to current nexthdr field in reassembled frame.
 368  *
 369  *      It is called with locked fq, and caller must check that
 370  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 371  *      the last and the first frames arrived and all the bits are here.
 372  */
 373 static struct sk_buff *
 374 nf_ct_frag6_reasm(struct frag_queue *fq, struct net_device *dev)
 375 {
 376         struct sk_buff *fp, *op, *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                 goto out_fail;
 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                 pr_debug("payload len is too large.\n");
 395                 goto out_oversize;
 396         }
 397
 398         /* Head of list must not be cloned. */
 399         if (skb_unclone(head, GFP_ATOMIC)) {
 400                 pr_debug("skb is cloned but can't expand head");
 401                 goto out_oom;
 402         }
 403
 404         /* If the first fragment is fragmented itself, we split
 405          * it to two chunks: the first with data and paged part
 406          * and the second, holding only fragments. */
 407         if (skb_has_frag_list(head)) {
 408                 struct sk_buff *clone;
 409                 int i, plen = 0;
 410
 411                 clone = alloc_skb(0, GFP_ATOMIC);
 412                 if (clone == NULL)
 413                         goto out_oom;
 414
 415                 clone->next = head->next;
 416                 head->next = clone;
 417                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 418                 skb_frag_list_init(head);
 419                 for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
 420                         plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
 421                 clone->len = clone->data_len = head->data_len - plen;
 422                 head->data_len -= clone->len;
 423                 head->len -= clone->len;
 424                 clone->csum = 0;
 425                 clone->ip_summed = head->ip_summed;
 426
 427                 NFCT_FRAG6_CB(clone)->orig = NULL;
 428                 add_frag_mem_limit(&fq->q, clone->truesize);
 429         }
 430
 431         /* We have to remove fragment header from datagram and to relocate
 432          * header in order to calculate ICV correctly. */
 433         skb_network_header(head)[fq->nhoffset] = skb_transport_header(head)[0];
 434         memmove(head->head + sizeof(struct frag_hdr), head->head,
 435                 (head->data - head->head) - sizeof(struct frag_hdr));
 436         head->mac_header += sizeof(struct frag_hdr);
 437         head->network_header += sizeof(struct frag_hdr);
 438
 439         skb_shinfo(head)->frag_list = head->next;
 440         skb_reset_transport_header(head);
 441         skb_push(head, head->data - skb_network_header(head));
 442
 443         for (fp=head->next; fp; fp = fp->next) {
 444                 head->data_len += fp->len;
 445                 head->len += fp->len;
 446                 if (head->ip_summed != fp->ip_summed)
 447                         head->ip_summed = CHECKSUM_NONE;
 448                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 449                         head->csum = csum_add(head->csum, fp->csum);
 450                 head->truesize += fp->truesize;
 451         }
 452         sub_frag_mem_limit(&fq->q, head->truesize);
 453
 454         head->local_df = 1;
 455         head->next = NULL;
 456         head->dev = dev;
 457         head->tstamp = fq->q.stamp;
 458         ipv6_hdr(head)->payload_len = htons(payload_len);
 459         ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
 460         IP6CB(head)->frag_max_size = sizeof(struct ipv6hdr) + fq->q.max_size;
 461
 462         /* Yes, and fold redundant checksum back. 8) */
 463         if (head->ip_summed == CHECKSUM_COMPLETE)
 464                 head->csum = csum_partial(skb_network_header(head),
 465                                           skb_network_header_len(head),
 466                                           head->csum);
 467
 468         fq->q.fragments = NULL;
 469         fq->q.fragments_tail = NULL;
 470
 471         /* all original skbs are linked into the NFCT_FRAG6_CB(head).orig */
 472         fp = skb_shinfo(head)->frag_list;
 473         if (fp && NFCT_FRAG6_CB(fp)->orig == NULL)
 474                 /* at above code, head skb is divided into two skbs. */
 475                 fp = fp->next;
 476
 477         op = NFCT_FRAG6_CB(head)->orig;
 478         for (; fp; fp = fp->next) {
 479                 struct sk_buff *orig = NFCT_FRAG6_CB(fp)->orig;
 480
 481                 op->next = orig;
 482                 op = orig;
 483                 NFCT_FRAG6_CB(fp)->orig = NULL;
 484         }
 485
 486         return head;
 487
 488 out_oversize:
 489         net_dbg_ratelimited("nf_ct_frag6_reasm: payload len = %d\n",
 490                             payload_len);
 491         goto out_fail;
 492 out_oom:
 493         net_dbg_ratelimited("nf_ct_frag6_reasm: no memory for reassembly\n");
 494 out_fail:
 495         return NULL;
 496 }
 497
 498 /*
 499  * find the header just before Fragment Header.
 500  *
 501  * if success return 0 and set ...
 502  * (*prevhdrp): the value of "Next Header Field" in the header
 503  *              just before Fragment Header.
 504  * (*prevhoff): the offset of "Next Header Field" in the header
 505  *              just before Fragment Header.
 506  * (*fhoff)   : the offset of Fragment Header.
 507  *
 508  * Based on ipv6_skip_hdr() in net/ipv6/exthdr.c
 509  *
 510  */
 511 static int
 512 find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff)
 513 {
 514         u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 515         const int netoff = skb_network_offset(skb);
 516         u8 prev_nhoff = netoff + offsetof(struct ipv6hdr, nexthdr);
 517         int start = netoff + sizeof(struct ipv6hdr);
 518         int len = skb->len - start;
 519         u8 prevhdr = NEXTHDR_IPV6;
 520
 521         while (nexthdr != NEXTHDR_FRAGMENT) {
 522                 struct ipv6_opt_hdr hdr;
 523                 int hdrlen;
 524
 525                 if (!ipv6_ext_hdr(nexthdr)) {
 526                         return -1;
 527                 }
 528                 if (nexthdr == NEXTHDR_NONE) {
 529                         pr_debug("next header is none\n");
 530                         return -1;
 531                 }
 532                 if (len < (int)sizeof(struct ipv6_opt_hdr)) {
 533                         pr_debug("too short\n");
 534                         return -1;
 535                 }
 536                 if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
 537                         BUG();
 538                 if (nexthdr == NEXTHDR_AUTH)
 539                         hdrlen = (hdr.hdrlen+2)<<2;
 540                 else
 541                         hdrlen = ipv6_optlen(&hdr);
 542
 543                 prevhdr = nexthdr;
 544                 prev_nhoff = start;
 545
 546                 nexthdr = hdr.nexthdr;
 547                 len -= hdrlen;
 548                 start += hdrlen;
 549         }
 550
 551         if (len < 0)
 552                 return -1;
 553
 554         *prevhdrp = prevhdr;
 555         *prevhoff = prev_nhoff;
 556         *fhoff = start;
 557
 558         return 0;
 559 }
 560
 561 struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user)
 562 {
 563         struct sk_buff *clone;
 564         struct net_device *dev = skb->dev;
 565         struct net *net = skb_dst(skb) ? dev_net(skb_dst(skb)->dev)
 566                                        : dev_net(skb->dev);
 567         struct frag_hdr *fhdr;
 568         struct frag_queue *fq;
 569         struct ipv6hdr *hdr;
 570         int fhoff, nhoff;
 571         u8 prevhdr;
 572         struct sk_buff *ret_skb = NULL;
 573
 574         /* Jumbo payload inhibits frag. header */
 575         if (ipv6_hdr(skb)->payload_len == 0) {
 576                 pr_debug("payload len = 0\n");
 577                 return skb;
 578         }
 579
 580         if (find_prev_fhdr(skb, &prevhdr, &nhoff, &fhoff) < 0)
 581                 return skb;
 582
 583         clone = skb_clone(skb, GFP_ATOMIC);
 584         if (clone == NULL) {
 585                 pr_debug("Can't clone skb\n");
 586                 return skb;
 587         }
 588
 589         NFCT_FRAG6_CB(clone)->orig = skb;
 590
 591         if (!pskb_may_pull(clone, fhoff + sizeof(*fhdr))) {
 592                 pr_debug("message is too short.\n");
 593                 goto ret_orig;
 594         }
 595
 596         skb_set_transport_header(clone, fhoff);
 597         hdr = ipv6_hdr(clone);
 598         fhdr = (struct frag_hdr *)skb_transport_header(clone);
 599
 600         local_bh_disable();
 601         inet_frag_evictor(&net->nf_frag.frags, &nf_frags, false);
 602         local_bh_enable();
 603
 604         fq = fq_find(net, fhdr->identification, user, &hdr->saddr, &hdr->daddr,
 605                      ip6_frag_ecn(hdr));
 606         if (fq == NULL) {
 607                 pr_debug("Can't find and can't create new queue\n");
 608                 goto ret_orig;
 609         }
 610
 611         spin_lock_bh(&fq->q.lock);
 612
 613         if (nf_ct_frag6_queue(fq, clone, fhdr, nhoff) < 0) {
 614                 spin_unlock_bh(&fq->q.lock);
 615                 pr_debug("Can't insert skb to queue\n");
 616                 inet_frag_put(&fq->q, &nf_frags);
 617                 goto ret_orig;
 618         }
 619
 620         if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 621             fq->q.meat == fq->q.len) {
 622                 ret_skb = nf_ct_frag6_reasm(fq, dev);
 623                 if (ret_skb == NULL)
 624                         pr_debug("Can't reassemble fragmented packets\n");
 625         }
 626         spin_unlock_bh(&fq->q.lock);
 627
 628         inet_frag_put(&fq->q, &nf_frags);
 629         return ret_skb;
 630
 631 ret_orig:
 632         kfree_skb(clone);
 633         return skb;
 634 }
 635
 636 void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
 637                         struct net_device *in, struct net_device *out,
 638                         int (*okfn)(struct sk_buff *))
 639 {
 640         struct sk_buff *s, *s2;
 641         unsigned int ret = 0;
 642
 643         for (s = NFCT_FRAG6_CB(skb)->orig; s;) {
 644                 nf_conntrack_put_reasm(s->nfct_reasm);
 645                 nf_conntrack_get_reasm(skb);
 646                 s->nfct_reasm = skb;
 647
 648                 s2 = s->next;
 649                 s->next = NULL;
 650
 651                 if (ret != -ECANCELED)
 652                         ret = NF_HOOK_THRESH(NFPROTO_IPV6, hooknum, s,
 653                                              in, out, okfn,
 654                                              NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
 655                 else
 656                         kfree_skb(s);
 657
 658                 s = s2;
 659         }
 660         nf_conntrack_put_reasm(skb);
 661 }
 662
 663 static int nf_ct_net_init(struct net *net)
 664 {
 665         net->nf_frag.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
 666         net->nf_frag.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
 667         net->nf_frag.frags.timeout = IPV6_FRAG_TIMEOUT;
 668         inet_frags_init_net(&net->nf_frag.frags);
 669
 670         return nf_ct_frag6_sysctl_register(net);
 671 }
 672
 673 static void nf_ct_net_exit(struct net *net)
 674 {
 675         nf_ct_frags6_sysctl_unregister(net);
 676         inet_frags_exit_net(&net->nf_frag.frags, &nf_frags);
 677 }
 678
 679 static struct pernet_operations nf_ct_net_ops = {
 680         .init = nf_ct_net_init,
 681         .exit = nf_ct_net_exit,
 682 };
 683
 684 int nf_ct_frag6_init(void)
 685 {
 686         int ret = 0;
 687
 688         nf_frags.hashfn = nf_hashfn;
 689         nf_frags.constructor = ip6_frag_init;
 690         nf_frags.destructor = NULL;
 691         nf_frags.skb_free = nf_skb_free;
 692         nf_frags.qsize = sizeof(struct frag_queue);
 693         nf_frags.match = ip6_frag_match;
 694         nf_frags.frag_expire = nf_ct_frag6_expire;
 695         nf_frags.secret_interval = 10 * 60 * HZ;
 696         inet_frags_init(&nf_frags);
 697
 698         ret = register_pernet_subsys(&nf_ct_net_ops);
 699         if (ret)
 700                 inet_frags_fini(&nf_frags);
 701
 702         return ret;
 703 }
 704
 705 void nf_ct_frag6_cleanup(void)
 706 {
 707         unregister_pernet_subsys(&nf_ct_net_ops);
 708         inet_frags_fini(&nf_frags);
 709 }