net/ipv6/netfilter/ip6_queue.c

   1 /*
   2  * This is a module which is used for queueing IPv6 packets and
   3  * communicating with userspace via netlink.
   4  *
   5  * (C) 2001 Fernando Anton, this code is GPL.
   6  *     IPv64 Project - Work based in IPv64 draft by Arturo Azcorra.
   7  *     Universidad Carlos III de Madrid - Leganes (Madrid) - Spain
   8  *     Universidad Politecnica de Alcala de Henares - Alcala de H. (Madrid) - Spain
   9  *     email: fanton@it.uc3m.es
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  *
  15  * 2001-11-06: First try. Working with ip_queue.c for IPv4 and trying
  16  *             to adapt it to IPv6
  17  *             HEAVILY based in ipqueue.c by James Morris. It's just
  18  *             a little modified version of it, so he's nearly the
  19  *             real coder of this.
  20  *             Few changes needed, mainly the hard_routing code and
  21  *             the netlink socket protocol (we're NETLINK_IP6_FW).
  22  * 2002-06-25: Code cleanup. [JM: ported cleanup over from ip_queue.c]
  23  */
  24 #include <linux/module.h>
  25 #include <linux/skbuff.h>
  26 #include <linux/init.h>
  27 #include <linux/ipv6.h>
  28 #include <linux/notifier.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/netfilter.h>
  31 #include <linux/netlink.h>
  32 #include <linux/spinlock.h>
  33 #include <linux/sysctl.h>
  34 #include <linux/proc_fs.h>
  35 #include <net/sock.h>
  36 #include <net/ipv6.h>
  37 #include <net/ip6_route.h>
  38 #include <linux/netfilter_ipv4/ip_queue.h>
  39 #include <linux/netfilter_ipv4/ip_tables.h>
  40 #include <linux/netfilter_ipv6/ip6_tables.h>
  41
  42 #define IPQ_QMAX_DEFAULT 1024
  43 #define IPQ_PROC_FS_NAME "ip6_queue"
  44 #define NET_IPQ_QMAX 2088
  45 #define NET_IPQ_QMAX_NAME "ip6_queue_maxlen"
  46
  47 struct ipq_rt_info {
  48         struct in6_addr daddr;
  49         struct in6_addr saddr;
  50 };
  51
  52 struct ipq_queue_entry {
  53         struct list_head list;
  54         struct nf_info *info;
  55         struct sk_buff *skb;
  56         struct ipq_rt_info rt_info;
  57 };
  58
  59 typedef int (*ipq_cmpfn)(struct ipq_queue_entry *, unsigned long);
  60
  61 static unsigned char copy_mode = IPQ_COPY_NONE;
  62 static unsigned int queue_maxlen = IPQ_QMAX_DEFAULT;
  63 static rwlock_t queue_lock = RW_LOCK_UNLOCKED;
  64 static int peer_pid;
  65 static unsigned int copy_range;
  66 static unsigned int queue_total;
  67 static struct sock *ipqnl;
  68 static LIST_HEAD(queue_list);
  69 static DECLARE_MUTEX(ipqnl_sem);
  70
  71 static void
  72 ipq_issue_verdict(struct ipq_queue_entry *entry, int verdict)
  73 {
  74         nf_reinject(entry->skb, entry->info, verdict);
  75         kfree(entry);
  76 }
  77
  78 static inline int
  79 __ipq_enqueue_entry(struct ipq_queue_entry *entry)
  80 {
  81        if (queue_total >= queue_maxlen) {
  82                if (net_ratelimit())
  83                        printk(KERN_WARNING "ip6_queue: full at %d entries, "
  84                               "dropping packet(s).\n", queue_total);
  85                return -ENOSPC;
  86        }
  87        list_add(&entry->list, &queue_list);
  88        queue_total++;
  89        return 0;
  90 }
  91
  92 /*
  93  * Find and return a queued entry matched by cmpfn, or return the last
  94  * entry if cmpfn is NULL.
  95  */
  96 static inline struct ipq_queue_entry *
  97 __ipq_find_entry(ipq_cmpfn cmpfn, unsigned long data)
  98 {
  99         struct list_head *p;
 100
 101         list_for_each_prev(p, &queue_list) {
 102                 struct ipq_queue_entry *entry = (struct ipq_queue_entry *)p;
 103
 104                 if (!cmpfn || cmpfn(entry, data))
 105                         return entry;
 106         }
 107         return NULL;
 108 }
 109
 110 static inline void
 111 __ipq_dequeue_entry(struct ipq_queue_entry *entry)
 112 {
 113         list_del(&entry->list);
 114         queue_total--;
 115 }
 116
 117 static inline struct ipq_queue_entry *
 118 __ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 119 {
 120         struct ipq_queue_entry *entry;
 121
 122         entry = __ipq_find_entry(cmpfn, data);
 123         if (entry == NULL)
 124                 return NULL;
 125
 126         __ipq_dequeue_entry(entry);
 127         return entry;
 128 }
 129
 130
 131 static inline void
 132 __ipq_flush(int verdict)
 133 {
 134         struct ipq_queue_entry *entry;
 135
 136         while ((entry = __ipq_find_dequeue_entry(NULL, 0)))
 137                 ipq_issue_verdict(entry, verdict);
 138 }
 139
 140 static inline int
 141 __ipq_set_mode(unsigned char mode, unsigned int range)
 142 {
 143         int status = 0;
 144
 145         switch(mode) {
 146         case IPQ_COPY_NONE:
 147         case IPQ_COPY_META:
 148                 copy_mode = mode;
 149                 copy_range = 0;
 150                 break;
 151
 152         case IPQ_COPY_PACKET:
 153                 copy_mode = mode;
 154                 copy_range = range;
 155                 if (copy_range > 0xFFFF)
 156                         copy_range = 0xFFFF;
 157                 break;
 158
 159         default:
 160                 status = -EINVAL;
 161
 162         }
 163         return status;
 164 }
 165
 166 static inline void
 167 __ipq_reset(void)
 168 {
 169         peer_pid = 0;
 170         __ipq_set_mode(IPQ_COPY_NONE, 0);
 171         __ipq_flush(NF_DROP);
 172 }
 173
 174 static struct ipq_queue_entry *
 175 ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 176 {
 177         struct ipq_queue_entry *entry;
 178
 179         write_lock_bh(&queue_lock);
 180         entry = __ipq_find_dequeue_entry(cmpfn, data);
 181         write_unlock_bh(&queue_lock);
 182         return entry;
 183 }
 184
 185 static void
 186 ipq_flush(int verdict)
 187 {
 188         write_lock_bh(&queue_lock);
 189         __ipq_flush(verdict);
 190         write_unlock_bh(&queue_lock);
 191 }
 192
 193 static struct sk_buff *
 194 ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
 195 {
 196         unsigned char *old_tail;
 197         size_t size = 0;
 198         size_t data_len = 0;
 199         struct sk_buff *skb;
 200         struct ipq_packet_msg *pmsg;
 201         struct nlmsghdr *nlh;
 202
 203         read_lock_bh(&queue_lock);
 204
 205         switch (copy_mode) {
 206         case IPQ_COPY_META:
 207         case IPQ_COPY_NONE:
 208                 size = NLMSG_SPACE(sizeof(*pmsg));
 209                 data_len = 0;
 210                 break;
 211
 212         case IPQ_COPY_PACKET:
 213                 if (copy_range == 0 || copy_range > entry->skb->len)
 214                         data_len = entry->skb->len;
 215                 else
 216                         data_len = copy_range;
 217
 218                 size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
 219                 break;
 220
 221         default:
 222                 *errp = -EINVAL;
 223                 read_unlock_bh(&queue_lock);
 224                 return NULL;
 225         }
 226
 227         read_unlock_bh(&queue_lock);
 228
 229         skb = alloc_skb(size, GFP_ATOMIC);
 230         if (!skb)
 231                 goto nlmsg_failure;
 232
 233         old_tail= skb->tail;
 234         nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
 235         pmsg = NLMSG_DATA(nlh);
 236         memset(pmsg, 0, sizeof(*pmsg));
 237
 238         pmsg->packet_id       = (unsigned long )entry;
 239         pmsg->data_len        = data_len;
 240         pmsg->timestamp_sec   = entry->skb->stamp.tv_sec;
 241         pmsg->timestamp_usec  = entry->skb->stamp.tv_usec;
 242         pmsg->mark            = entry->skb->nfmark;
 243         pmsg->hook            = entry->info->hook;
 244         pmsg->hw_protocol     = entry->skb->protocol;
 245
 246         if (entry->info->indev)
 247                 strcpy(pmsg->indev_name, entry->info->indev->name);
 248         else
 249                 pmsg->indev_name[0] = '\0';
 250
 251         if (entry->info->outdev)
 252                 strcpy(pmsg->outdev_name, entry->info->outdev->name);
 253         else
 254                 pmsg->outdev_name[0] = '\0';
 255
 256         if (entry->info->indev && entry->skb->dev) {
 257                 pmsg->hw_type = entry->skb->dev->type;
 258                 if (entry->skb->dev->hard_header_parse)
 259                         pmsg->hw_addrlen =
 260                                 entry->skb->dev->hard_header_parse(entry->skb,
 261                                                                    pmsg->hw_addr);
 262         }
 263
 264         if (data_len)
 265                 memcpy(pmsg->payload, entry->skb->data, data_len);
 266
 267         nlh->nlmsg_len = skb->tail - old_tail;
 268         return skb;
 269
 270 nlmsg_failure:
 271         if (skb)
 272                 kfree_skb(skb);
 273         *errp = -EINVAL;
 274         printk(KERN_ERR "ip6_queue: error creating packet message\n");
 275         return NULL;
 276 }
 277
 278 static int
 279 ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, void *data)
 280 {
 281         int status = -EINVAL;
 282         struct sk_buff *nskb;
 283         struct ipq_queue_entry *entry;
 284
 285         if (copy_mode == IPQ_COPY_NONE)
 286                 return -EAGAIN;
 287
 288         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 289         if (entry == NULL) {
 290                 printk(KERN_ERR "ip6_queue: OOM in ipq_enqueue_packet()\n");
 291                 return -ENOMEM;
 292         }
 293
 294         entry->info = info;
 295         entry->skb = skb;
 296
 297         if (entry->info->hook == NF_IP_LOCAL_OUT) {
 298                 struct ipv6hdr *iph = skb->nh.ipv6h;
 299
 300                 entry->rt_info.daddr = iph->daddr;
 301                 entry->rt_info.saddr = iph->saddr;
 302         }
 303
 304         nskb = ipq_build_packet_message(entry, &status);
 305         if (nskb == NULL)
 306                 goto err_out_free;
 307
 308         write_lock_bh(&queue_lock);
 309
 310         if (!peer_pid)
 311                 goto err_out_free_nskb;
 312
 313         /* netlink_unicast will either free the nskb or attach it to a socket */
 314         status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
 315         if (status < 0)
 316                 goto err_out_unlock;
 317
 318         status = __ipq_enqueue_entry(entry);
 319         if (status < 0)
 320                 goto err_out_unlock;
 321
 322         write_unlock_bh(&queue_lock);
 323         return status;
 324
 325 err_out_free_nskb:
 326         kfree_skb(nskb);
 327
 328 err_out_unlock:
 329         write_unlock_bh(&queue_lock);
 330
 331 err_out_free:
 332         kfree(entry);
 333         return status;
 334 }
 335
 336 static int
 337 ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
 338 {
 339         int diff;
 340         struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload;
 341
 342         if (v->data_len < sizeof(*user_iph))
 343                 return 0;
 344         diff = v->data_len - e->skb->len;
 345         if (diff < 0)
 346                 skb_trim(e->skb, v->data_len);
 347         else if (diff > 0) {
 348                 if (v->data_len > 0xFFFF)
 349                         return -EINVAL;
 350                 if (diff > skb_tailroom(e->skb)) {
 351                         struct sk_buff *newskb;
 352
 353                         newskb = skb_copy_expand(e->skb,
 354                                                  skb_headroom(e->skb),
 355                                                  diff,
 356                                                  GFP_ATOMIC);
 357                         if (newskb == NULL) {
 358                                 printk(KERN_WARNING "ip6_queue: OOM "
 359                                       "in mangle, dropping packet\n");
 360                                 return -ENOMEM;
 361                         }
 362                         if (e->skb->sk)
 363                                 skb_set_owner_w(newskb, e->skb->sk);
 364                         kfree_skb(e->skb);
 365                         e->skb = newskb;
 366                 }
 367                 skb_put(e->skb, diff);
 368         }
 369         memcpy(e->skb->data, v->payload, v->data_len);
 370         e->skb->nfcache |= NFC_ALTERED;
 371
 372         /*
 373          * Extra routing may needed on local out, as the QUEUE target never
 374          * returns control to the table.
 375          * Not a nice way to cmp, but works
 376          */
 377         if (e->info->hook == NF_IP_LOCAL_OUT) {
 378                 struct ipv6hdr *iph = e->skb->nh.ipv6h;
 379                 if (ipv6_addr_cmp(&iph->daddr, &e->rt_info.daddr) ||
 380                     ipv6_addr_cmp(&iph->saddr, &e->rt_info.saddr))
 381                         return ip6_route_me_harder(e->skb);
 382         }
 383         return 0;
 384 }
 385
 386 static inline int
 387 id_cmp(struct ipq_queue_entry *e, unsigned long id)
 388 {
 389         return (id == (unsigned long )e);
 390 }
 391
 392 static int
 393 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
 394 {
 395         struct ipq_queue_entry *entry;
 396
 397         if (vmsg->value > NF_MAX_VERDICT)
 398                 return -EINVAL;
 399
 400         entry = ipq_find_dequeue_entry(id_cmp, vmsg->id);
 401         if (entry == NULL)
 402                 return -ENOENT;
 403         else {
 404                 int verdict = vmsg->value;
 405
 406                 if (vmsg->data_len && vmsg->data_len == len)
 407                         if (ipq_mangle_ipv6(vmsg, entry) < 0)
 408                                 verdict = NF_DROP;
 409
 410                 ipq_issue_verdict(entry, verdict);
 411                 return 0;
 412         }
 413 }
 414
 415 static int
 416 ipq_set_mode(unsigned char mode, unsigned int range)
 417 {
 418         int status;
 419
 420         write_lock_bh(&queue_lock);
 421         status = __ipq_set_mode(mode, range);
 422         write_unlock_bh(&queue_lock);
 423         return status;
 424 }
 425
 426 static int
 427 ipq_receive_peer(struct ipq_peer_msg *pmsg,
 428                  unsigned char type, unsigned int len)
 429 {
 430         int status = 0;
 431
 432         if (len < sizeof(*pmsg))
 433                 return -EINVAL;
 434
 435         switch (type) {
 436         case IPQM_MODE:
 437                 status = ipq_set_mode(pmsg->msg.mode.value,
 438                                       pmsg->msg.mode.range);
 439                 break;
 440
 441         case IPQM_VERDICT:
 442                 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
 443                         status = -EINVAL;
 444                 else
 445                         status = ipq_set_verdict(&pmsg->msg.verdict,
 446                                                  len - sizeof(*pmsg));
 447                         break;
 448         default:
 449                 status = -EINVAL;
 450         }
 451         return status;
 452 }
 453
 454 static int
 455 dev_cmp(struct ipq_queue_entry *entry, unsigned long ifindex)
 456 {
 457         if (entry->info->indev)
 458                 if (entry->info->indev->ifindex == ifindex)
 459                         return 1;
 460
 461         if (entry->info->outdev)
 462                 if (entry->info->outdev->ifindex == ifindex)
 463                         return 1;
 464
 465         return 0;
 466 }
 467
 468 static void
 469 ipq_dev_drop(int ifindex)
 470 {
 471         struct ipq_queue_entry *entry;
 472
 473         while ((entry = ipq_find_dequeue_entry(dev_cmp, ifindex)) != NULL)
 474                 ipq_issue_verdict(entry, NF_DROP);
 475 }
 476
 477 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 478
 479 static inline void
 480 ipq_rcv_skb(struct sk_buff *skb)
 481 {
 482         int status, type, pid, flags, nlmsglen, skblen;
 483         struct nlmsghdr *nlh;
 484
 485         skblen = skb->len;
 486         if (skblen < sizeof(*nlh))
 487                 return;
 488
 489         nlh = (struct nlmsghdr *)skb->data;
 490         nlmsglen = nlh->nlmsg_len;
 491         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
 492                 return;
 493
 494         pid = nlh->nlmsg_pid;
 495         flags = nlh->nlmsg_flags;
 496
 497         if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
 498                 RCV_SKB_FAIL(-EINVAL);
 499
 500         if (flags & MSG_TRUNC)
 501                 RCV_SKB_FAIL(-ECOMM);
 502
 503         type = nlh->nlmsg_type;
 504         if (type < NLMSG_NOOP || type >= IPQM_MAX)
 505                 RCV_SKB_FAIL(-EINVAL);
 506
 507         if (type <= IPQM_BASE)
 508                 return;
 509
 510         if (security_netlink_recv(skb))
 511                 RCV_SKB_FAIL(-EPERM);
 512
 513         write_lock_bh(&queue_lock);
 514
 515         if (peer_pid) {
 516                 if (peer_pid != pid) {
 517                         write_unlock_bh(&queue_lock);
 518                         RCV_SKB_FAIL(-EBUSY);
 519                 }
 520         }
 521         else
 522                 peer_pid = pid;
 523
 524         write_unlock_bh(&queue_lock);
 525
 526         status = ipq_receive_peer(NLMSG_DATA(nlh), type,
 527                                   skblen - NLMSG_LENGTH(0));
 528         if (status < 0)
 529                 RCV_SKB_FAIL(status);
 530
 531         if (flags & NLM_F_ACK)
 532                 netlink_ack(skb, nlh, 0);
 533         return;
 534 }
 535
 536 static void
 537 ipq_rcv_sk(struct sock *sk, int len)
 538 {
 539         do {
 540                 struct sk_buff *skb;
 541
 542                 if (down_trylock(&ipqnl_sem))
 543                         return;
 544
 545                 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
 546                         ipq_rcv_skb(skb);
 547                         kfree_skb(skb);
 548                 }
 549
 550                 up(&ipqnl_sem);
 551
 552         } while (ipqnl && ipqnl->sk_receive_queue.qlen);
 553 }
 554
 555 static int
 556 ipq_rcv_dev_event(struct notifier_block *this,
 557                   unsigned long event, void *ptr)
 558 {
 559         struct net_device *dev = ptr;
 560
 561         /* Drop any packets associated with the downed device */
 562         if (event == NETDEV_DOWN)
 563                 ipq_dev_drop(dev->ifindex);
 564         return NOTIFY_DONE;
 565 }
 566
 567 static struct notifier_block ipq_dev_notifier = {
 568         .notifier_call  = ipq_rcv_dev_event,
 569 };
 570
 571 static int
 572 ipq_rcv_nl_event(struct notifier_block *this,
 573                  unsigned long event, void *ptr)
 574 {
 575         struct netlink_notify *n = ptr;
 576
 577         if (event == NETLINK_URELEASE &&
 578             n->protocol == NETLINK_IP6_FW && n->pid) {
 579                 write_lock_bh(&queue_lock);
 580                 if (n->pid == peer_pid)
 581                         __ipq_reset();
 582                 write_unlock_bh(&queue_lock);
 583         }
 584         return NOTIFY_DONE;
 585 }
 586
 587 static struct notifier_block ipq_nl_notifier = {
 588         .notifier_call  = ipq_rcv_nl_event,
 589 };
 590
 591 static struct ctl_table_header *ipq_sysctl_header;
 592
 593 static ctl_table ipq_table[] = {
 594         {
 595                 .ctl_name       = NET_IPQ_QMAX,
 596                 .procname       = NET_IPQ_QMAX_NAME,
 597                 .data           = &queue_maxlen,
 598                 .maxlen         = sizeof(queue_maxlen),
 599                 .mode           = 0644,
 600                 .proc_handler   = proc_dointvec
 601         },
 602         { .ctl_name = 0 }
 603 };
 604
 605 static ctl_table ipq_dir_table[] = {
 606         {
 607                 .ctl_name       = NET_IPV6,
 608                 .procname       = "ipv6",
 609                 .mode           = 0555,
 610                 .child          = ipq_table
 611         },
 612         { .ctl_name = 0 }
 613 };
 614
 615 static ctl_table ipq_root_table[] = {
 616         {
 617                 .ctl_name       = CTL_NET,
 618                 .procname       = "net",
 619                 .mode           = 0555,
 620                 .child          = ipq_dir_table
 621         },
 622         { .ctl_name = 0 }
 623 };
 624
 625 static int
 626 ipq_get_info(char *buffer, char **start, off_t offset, int length)
 627 {
 628         int len;
 629
 630         read_lock_bh(&queue_lock);
 631
 632         len = sprintf(buffer,
 633                       "Peer PID          : %d\n"
 634                       "Copy mode         : %hu\n"
 635                       "Copy range        : %u\n"
 636                       "Queue length      : %u\n"
 637                       "Queue max. length : %u\n",
 638                       peer_pid,
 639                       copy_mode,
 640                       copy_range,
 641                       queue_total,
 642                       queue_maxlen);
 643
 644         read_unlock_bh(&queue_lock);
 645
 646         *start = buffer + offset;
 647         len -= offset;
 648         if (len > length)
 649                 len = length;
 650         else if (len < 0)
 651                 len = 0;
 652         return len;
 653 }
 654
 655 static int
 656 init_or_cleanup(int init)
 657 {
 658         int status = -ENOMEM;
 659         struct proc_dir_entry *proc;
 660
 661         if (!init)
 662                 goto cleanup;
 663
 664         netlink_register_notifier(&ipq_nl_notifier);
 665         ipqnl = netlink_kernel_create(NETLINK_IP6_FW, ipq_rcv_sk);
 666         if (ipqnl == NULL) {
 667                 printk(KERN_ERR "ip6_queue: failed to create netlink socket\n");
 668                 goto cleanup_netlink_notifier;
 669         }
 670
 671         proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
 672         if (proc)
 673                 proc->owner = THIS_MODULE;
 674         else {
 675                 printk(KERN_ERR "ip6_queue: failed to create proc entry\n");
 676                 goto cleanup_ipqnl;
 677         }
 678
 679         register_netdevice_notifier(&ipq_dev_notifier);
 680         ipq_sysctl_header = register_sysctl_table(ipq_root_table, 0);
 681
 682         status = nf_register_queue_handler(PF_INET6, ipq_enqueue_packet, NULL);
 683         if (status < 0) {
 684                 printk(KERN_ERR "ip6_queue: failed to register queue handler\n");
 685                 goto cleanup_sysctl;
 686         }
 687         return status;
 688
 689 cleanup:
 690         nf_unregister_queue_handler(PF_INET6);
 691         synchronize_net();
 692         ipq_flush(NF_DROP);
 693
 694 cleanup_sysctl:
 695         unregister_sysctl_table(ipq_sysctl_header);
 696         unregister_netdevice_notifier(&ipq_dev_notifier);
 697         proc_net_remove(IPQ_PROC_FS_NAME);
 698
 699 cleanup_ipqnl:
 700         sock_release(ipqnl->sk_socket);
 701         down(&ipqnl_sem);
 702         up(&ipqnl_sem);
 703
 704 cleanup_netlink_notifier:
 705         netlink_unregister_notifier(&ipq_nl_notifier);
 706         return status;
 707 }
 708
 709 static int __init init(void)
 710 {
 711
 712         return init_or_cleanup(1);
 713 }
 714
 715 static void __exit fini(void)
 716 {
 717         init_or_cleanup(0);
 718 }
 719
 720 MODULE_DESCRIPTION("IPv6 packet queue handler");
 721 MODULE_LICENSE("GPL");
 722
 723 module_init(init);
 724 module_exit(fini);