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  * 2005-02-04: Added /proc counter for dropped packets; fixed so
  24  *             packets aren't delivered to user space if they're going
  25  *             to be dropped.
  26  */
  27 #include <linux/module.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/init.h>
  30 #include <linux/ipv6.h>
  31 #include <linux/notifier.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/netfilter.h>
  34 #include <linux/netlink.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/sysctl.h>
  37 #include <linux/proc_fs.h>
  38 #include <net/sock.h>
  39 #include <net/ipv6.h>
  40 #include <net/ip6_route.h>
  41 #include <linux/netfilter_ipv4/ip_queue.h>
  42 #include <linux/netfilter_ipv4/ip_tables.h>
  43 #include <linux/netfilter_ipv6/ip6_tables.h>
  44
  45 #define IPQ_QMAX_DEFAULT 1024
  46 #define IPQ_PROC_FS_NAME "ip6_queue"
  47 #define NET_IPQ_QMAX 2088
  48 #define NET_IPQ_QMAX_NAME "ip6_queue_maxlen"
  49
  50 struct ipq_queue_entry {
  51         struct list_head list;
  52         struct nf_info *info;
  53         struct sk_buff *skb;
  54 };
  55
  56 typedef int (*ipq_cmpfn)(struct ipq_queue_entry *, unsigned long);
  57
  58 static unsigned char copy_mode = IPQ_COPY_NONE;
  59 static unsigned int queue_maxlen = IPQ_QMAX_DEFAULT;
  60 static DEFINE_RWLOCK(queue_lock);
  61 static int peer_pid;
  62 static unsigned int copy_range;
  63 static unsigned int queue_total;
  64 static unsigned int queue_dropped = 0;
  65 static unsigned int queue_user_dropped = 0;
  66 static struct sock *ipqnl;
  67 static LIST_HEAD(queue_list);
  68 static DECLARE_MUTEX(ipqnl_sem);
  69
  70 static void
  71 ipq_issue_verdict(struct ipq_queue_entry *entry, int verdict)
  72 {
  73         local_bh_disable();
  74         nf_reinject(entry->skb, entry->info, verdict);
  75         local_bh_enable();
  76         kfree(entry);
  77 }
  78
  79 static inline void
  80 __ipq_enqueue_entry(struct ipq_queue_entry *entry)
  81 {
  82        list_add(&entry->list, &queue_list);
  83        queue_total++;
  84 }
  85
  86 /*
  87  * Find and return a queued entry matched by cmpfn, or return the last
  88  * entry if cmpfn is NULL.
  89  */
  90 static inline struct ipq_queue_entry *
  91 __ipq_find_entry(ipq_cmpfn cmpfn, unsigned long data)
  92 {
  93         struct list_head *p;
  94
  95         list_for_each_prev(p, &queue_list) {
  96                 struct ipq_queue_entry *entry = (struct ipq_queue_entry *)p;
  97
  98                 if (!cmpfn || cmpfn(entry, data))
  99                         return entry;
 100         }
 101         return NULL;
 102 }
 103
 104 static inline void
 105 __ipq_dequeue_entry(struct ipq_queue_entry *entry)
 106 {
 107         list_del(&entry->list);
 108         queue_total--;
 109 }
 110
 111 static inline struct ipq_queue_entry *
 112 __ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 113 {
 114         struct ipq_queue_entry *entry;
 115
 116         entry = __ipq_find_entry(cmpfn, data);
 117         if (entry == NULL)
 118                 return NULL;
 119
 120         __ipq_dequeue_entry(entry);
 121         return entry;
 122 }
 123
 124
 125 static inline void
 126 __ipq_flush(int verdict)
 127 {
 128         struct ipq_queue_entry *entry;
 129
 130         while ((entry = __ipq_find_dequeue_entry(NULL, 0)))
 131                 ipq_issue_verdict(entry, verdict);
 132 }
 133
 134 static inline int
 135 __ipq_set_mode(unsigned char mode, unsigned int range)
 136 {
 137         int status = 0;
 138
 139         switch(mode) {
 140         case IPQ_COPY_NONE:
 141         case IPQ_COPY_META:
 142                 copy_mode = mode;
 143                 copy_range = 0;
 144                 break;
 145
 146         case IPQ_COPY_PACKET:
 147                 copy_mode = mode;
 148                 copy_range = range;
 149                 if (copy_range > 0xFFFF)
 150                         copy_range = 0xFFFF;
 151                 break;
 152
 153         default:
 154                 status = -EINVAL;
 155
 156         }
 157         return status;
 158 }
 159
 160 static inline void
 161 __ipq_reset(void)
 162 {
 163         peer_pid = 0;
 164         net_disable_timestamp();
 165         __ipq_set_mode(IPQ_COPY_NONE, 0);
 166         __ipq_flush(NF_DROP);
 167 }
 168
 169 static struct ipq_queue_entry *
 170 ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 171 {
 172         struct ipq_queue_entry *entry;
 173
 174         write_lock_bh(&queue_lock);
 175         entry = __ipq_find_dequeue_entry(cmpfn, data);
 176         write_unlock_bh(&queue_lock);
 177         return entry;
 178 }
 179
 180 static void
 181 ipq_flush(int verdict)
 182 {
 183         write_lock_bh(&queue_lock);
 184         __ipq_flush(verdict);
 185         write_unlock_bh(&queue_lock);
 186 }
 187
 188 static struct sk_buff *
 189 ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
 190 {
 191         unsigned char *old_tail;
 192         size_t size = 0;
 193         size_t data_len = 0;
 194         struct sk_buff *skb;
 195         struct ipq_packet_msg *pmsg;
 196         struct nlmsghdr *nlh;
 197
 198         read_lock_bh(&queue_lock);
 199
 200         switch (copy_mode) {
 201         case IPQ_COPY_META:
 202         case IPQ_COPY_NONE:
 203                 size = NLMSG_SPACE(sizeof(*pmsg));
 204                 data_len = 0;
 205                 break;
 206
 207         case IPQ_COPY_PACKET:
 208                 if (entry->skb->ip_summed == CHECKSUM_HW &&
 209                     (*errp = skb_checksum_help(entry->skb,
 210                                                entry->info->outdev == NULL))) {
 211                         read_unlock_bh(&queue_lock);
 212                         return NULL;
 213                 }
 214                 if (copy_range == 0 || copy_range > entry->skb->len)
 215                         data_len = entry->skb->len;
 216                 else
 217                         data_len = copy_range;
 218
 219                 size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
 220                 break;
 221
 222         default:
 223                 *errp = -EINVAL;
 224                 read_unlock_bh(&queue_lock);
 225                 return NULL;
 226         }
 227
 228         read_unlock_bh(&queue_lock);
 229
 230         skb = alloc_skb(size, GFP_ATOMIC);
 231         if (!skb)
 232                 goto nlmsg_failure;
 233
 234         old_tail= skb->tail;
 235         nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
 236         pmsg = NLMSG_DATA(nlh);
 237         memset(pmsg, 0, sizeof(*pmsg));
 238
 239         pmsg->packet_id       = (unsigned long )entry;
 240         pmsg->data_len        = data_len;
 241         pmsg->timestamp_sec   = entry->skb->tstamp.off_sec;
 242         pmsg->timestamp_usec  = entry->skb->tstamp.off_usec;
 243         pmsg->mark            = entry->skb->nfmark;
 244         pmsg->hook            = entry->info->hook;
 245         pmsg->hw_protocol     = entry->skb->protocol;
 246
 247         if (entry->info->indev)
 248                 strcpy(pmsg->indev_name, entry->info->indev->name);
 249         else
 250                 pmsg->indev_name[0] = '\0';
 251
 252         if (entry->info->outdev)
 253                 strcpy(pmsg->outdev_name, entry->info->outdev->name);
 254         else
 255                 pmsg->outdev_name[0] = '\0';
 256
 257         if (entry->info->indev && entry->skb->dev) {
 258                 pmsg->hw_type = entry->skb->dev->type;
 259                 if (entry->skb->dev->hard_header_parse)
 260                         pmsg->hw_addrlen =
 261                                 entry->skb->dev->hard_header_parse(entry->skb,
 262                                                                    pmsg->hw_addr);
 263         }
 264
 265         if (data_len)
 266                 if (skb_copy_bits(entry->skb, 0, pmsg->payload, data_len))
 267                         BUG();
 268
 269         nlh->nlmsg_len = skb->tail - old_tail;
 270         return skb;
 271
 272 nlmsg_failure:
 273         if (skb)
 274                 kfree_skb(skb);
 275         *errp = -EINVAL;
 276         printk(KERN_ERR "ip6_queue: error creating packet message\n");
 277         return NULL;
 278 }
 279
 280 static int
 281 ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info,
 282                    unsigned int queuenum, void *data)
 283 {
 284         int status = -EINVAL;
 285         struct sk_buff *nskb;
 286         struct ipq_queue_entry *entry;
 287
 288         if (copy_mode == IPQ_COPY_NONE)
 289                 return -EAGAIN;
 290
 291         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 292         if (entry == NULL) {
 293                 printk(KERN_ERR "ip6_queue: OOM in ipq_enqueue_packet()\n");
 294                 return -ENOMEM;
 295         }
 296
 297         entry->info = info;
 298         entry->skb = skb;
 299
 300         nskb = ipq_build_packet_message(entry, &status);
 301         if (nskb == NULL)
 302                 goto err_out_free;
 303
 304         write_lock_bh(&queue_lock);
 305
 306         if (!peer_pid)
 307                 goto err_out_free_nskb;
 308
 309         if (queue_total >= queue_maxlen) {
 310                 queue_dropped++;
 311                 status = -ENOSPC;
 312                 if (net_ratelimit())
 313                         printk (KERN_WARNING "ip6_queue: fill at %d entries, "
 314                                 "dropping packet(s).  Dropped: %d\n", queue_total,
 315                                 queue_dropped);
 316                 goto err_out_free_nskb;
 317         }
 318
 319         /* netlink_unicast will either free the nskb or attach it to a socket */
 320         status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
 321         if (status < 0) {
 322                 queue_user_dropped++;
 323                 goto err_out_unlock;
 324         }
 325
 326         __ipq_enqueue_entry(entry);
 327
 328         write_unlock_bh(&queue_lock);
 329         return status;
 330
 331 err_out_free_nskb:
 332         kfree_skb(nskb);
 333
 334 err_out_unlock:
 335         write_unlock_bh(&queue_lock);
 336
 337 err_out_free:
 338         kfree(entry);
 339         return status;
 340 }
 341
 342 static int
 343 ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
 344 {
 345         int diff;
 346         struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload;
 347
 348         if (v->data_len < sizeof(*user_iph))
 349                 return 0;
 350         diff = v->data_len - e->skb->len;
 351         if (diff < 0)
 352                 skb_trim(e->skb, v->data_len);
 353         else if (diff > 0) {
 354                 if (v->data_len > 0xFFFF)
 355                         return -EINVAL;
 356                 if (diff > skb_tailroom(e->skb)) {
 357                         struct sk_buff *newskb;
 358
 359                         newskb = skb_copy_expand(e->skb,
 360                                                  skb_headroom(e->skb),
 361                                                  diff,
 362                                                  GFP_ATOMIC);
 363                         if (newskb == NULL) {
 364                                 printk(KERN_WARNING "ip6_queue: OOM "
 365                                       "in mangle, dropping packet\n");
 366                                 return -ENOMEM;
 367                         }
 368                         if (e->skb->sk)
 369                                 skb_set_owner_w(newskb, e->skb->sk);
 370                         kfree_skb(e->skb);
 371                         e->skb = newskb;
 372                 }
 373                 skb_put(e->skb, diff);
 374         }
 375         if (!skb_make_writable(&e->skb, v->data_len))
 376                 return -ENOMEM;
 377         memcpy(e->skb->data, v->payload, v->data_len);
 378         e->skb->ip_summed = CHECKSUM_NONE;
 379
 380         return 0;
 381 }
 382
 383 static inline int
 384 id_cmp(struct ipq_queue_entry *e, unsigned long id)
 385 {
 386         return (id == (unsigned long )e);
 387 }
 388
 389 static int
 390 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
 391 {
 392         struct ipq_queue_entry *entry;
 393
 394         if (vmsg->value > NF_MAX_VERDICT)
 395                 return -EINVAL;
 396
 397         entry = ipq_find_dequeue_entry(id_cmp, vmsg->id);
 398         if (entry == NULL)
 399                 return -ENOENT;
 400         else {
 401                 int verdict = vmsg->value;
 402
 403                 if (vmsg->data_len && vmsg->data_len == len)
 404                         if (ipq_mangle_ipv6(vmsg, entry) < 0)
 405                                 verdict = NF_DROP;
 406
 407                 ipq_issue_verdict(entry, verdict);
 408                 return 0;
 409         }
 410 }
 411
 412 static int
 413 ipq_set_mode(unsigned char mode, unsigned int range)
 414 {
 415         int status;
 416
 417         write_lock_bh(&queue_lock);
 418         status = __ipq_set_mode(mode, range);
 419         write_unlock_bh(&queue_lock);
 420         return status;
 421 }
 422
 423 static int
 424 ipq_receive_peer(struct ipq_peer_msg *pmsg,
 425                  unsigned char type, unsigned int len)
 426 {
 427         int status = 0;
 428
 429         if (len < sizeof(*pmsg))
 430                 return -EINVAL;
 431
 432         switch (type) {
 433         case IPQM_MODE:
 434                 status = ipq_set_mode(pmsg->msg.mode.value,
 435                                       pmsg->msg.mode.range);
 436                 break;
 437
 438         case IPQM_VERDICT:
 439                 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
 440                         status = -EINVAL;
 441                 else
 442                         status = ipq_set_verdict(&pmsg->msg.verdict,
 443                                                  len - sizeof(*pmsg));
 444                         break;
 445         default:
 446                 status = -EINVAL;
 447         }
 448         return status;
 449 }
 450
 451 static int
 452 dev_cmp(struct ipq_queue_entry *entry, unsigned long ifindex)
 453 {
 454         if (entry->info->indev)
 455                 if (entry->info->indev->ifindex == ifindex)
 456                         return 1;
 457
 458         if (entry->info->outdev)
 459                 if (entry->info->outdev->ifindex == ifindex)
 460                         return 1;
 461
 462         return 0;
 463 }
 464
 465 static void
 466 ipq_dev_drop(int ifindex)
 467 {
 468         struct ipq_queue_entry *entry;
 469
 470         while ((entry = ipq_find_dequeue_entry(dev_cmp, ifindex)) != NULL)
 471                 ipq_issue_verdict(entry, NF_DROP);
 472 }
 473
 474 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 475
 476 static inline void
 477 ipq_rcv_skb(struct sk_buff *skb)
 478 {
 479         int status, type, pid, flags, nlmsglen, skblen;
 480         struct nlmsghdr *nlh;
 481
 482         skblen = skb->len;
 483         if (skblen < sizeof(*nlh))
 484                 return;
 485
 486         nlh = (struct nlmsghdr *)skb->data;
 487         nlmsglen = nlh->nlmsg_len;
 488         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
 489                 return;
 490
 491         pid = nlh->nlmsg_pid;
 492         flags = nlh->nlmsg_flags;
 493
 494         if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
 495                 RCV_SKB_FAIL(-EINVAL);
 496
 497         if (flags & MSG_TRUNC)
 498                 RCV_SKB_FAIL(-ECOMM);
 499
 500         type = nlh->nlmsg_type;
 501         if (type < NLMSG_NOOP || type >= IPQM_MAX)
 502                 RCV_SKB_FAIL(-EINVAL);
 503
 504         if (type <= IPQM_BASE)
 505                 return;
 506
 507         if (security_netlink_recv(skb))
 508                 RCV_SKB_FAIL(-EPERM);
 509
 510         write_lock_bh(&queue_lock);
 511
 512         if (peer_pid) {
 513                 if (peer_pid != pid) {
 514                         write_unlock_bh(&queue_lock);
 515                         RCV_SKB_FAIL(-EBUSY);
 516                 }
 517         } else {
 518                 net_enable_timestamp();
 519                 peer_pid = pid;
 520         }
 521
 522         write_unlock_bh(&queue_lock);
 523
 524         status = ipq_receive_peer(NLMSG_DATA(nlh), type,
 525                                   skblen - NLMSG_LENGTH(0));
 526         if (status < 0)
 527                 RCV_SKB_FAIL(status);
 528
 529         if (flags & NLM_F_ACK)
 530                 netlink_ack(skb, nlh, 0);
 531         return;
 532 }
 533
 534 static void
 535 ipq_rcv_sk(struct sock *sk, int len)
 536 {
 537         struct sk_buff *skb;
 538         unsigned int qlen;
 539
 540         down(&ipqnl_sem);
 541
 542         for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
 543                 skb = skb_dequeue(&sk->sk_receive_queue);
 544                 ipq_rcv_skb(skb);
 545                 kfree_skb(skb);
 546         }
 547
 548         up(&ipqnl_sem);
 549 }
 550
 551 static int
 552 ipq_rcv_dev_event(struct notifier_block *this,
 553                   unsigned long event, void *ptr)
 554 {
 555         struct net_device *dev = ptr;
 556
 557         /* Drop any packets associated with the downed device */
 558         if (event == NETDEV_DOWN)
 559                 ipq_dev_drop(dev->ifindex);
 560         return NOTIFY_DONE;
 561 }
 562
 563 static struct notifier_block ipq_dev_notifier = {
 564         .notifier_call  = ipq_rcv_dev_event,
 565 };
 566
 567 static int
 568 ipq_rcv_nl_event(struct notifier_block *this,
 569                  unsigned long event, void *ptr)
 570 {
 571         struct netlink_notify *n = ptr;
 572
 573         if (event == NETLINK_URELEASE &&
 574             n->protocol == NETLINK_IP6_FW && n->pid) {
 575                 write_lock_bh(&queue_lock);
 576                 if (n->pid == peer_pid)
 577                         __ipq_reset();
 578                 write_unlock_bh(&queue_lock);
 579         }
 580         return NOTIFY_DONE;
 581 }
 582
 583 static struct notifier_block ipq_nl_notifier = {
 584         .notifier_call  = ipq_rcv_nl_event,
 585 };
 586
 587 static struct ctl_table_header *ipq_sysctl_header;
 588
 589 static ctl_table ipq_table[] = {
 590         {
 591                 .ctl_name       = NET_IPQ_QMAX,
 592                 .procname       = NET_IPQ_QMAX_NAME,
 593                 .data           = &queue_maxlen,
 594                 .maxlen         = sizeof(queue_maxlen),
 595                 .mode           = 0644,
 596                 .proc_handler   = proc_dointvec
 597         },
 598         { .ctl_name = 0 }
 599 };
 600
 601 static ctl_table ipq_dir_table[] = {
 602         {
 603                 .ctl_name       = NET_IPV6,
 604                 .procname       = "ipv6",
 605                 .mode           = 0555,
 606                 .child          = ipq_table
 607         },
 608         { .ctl_name = 0 }
 609 };
 610
 611 static ctl_table ipq_root_table[] = {
 612         {
 613                 .ctl_name       = CTL_NET,
 614                 .procname       = "net",
 615                 .mode           = 0555,
 616                 .child          = ipq_dir_table
 617         },
 618         { .ctl_name = 0 }
 619 };
 620
 621 static int
 622 ipq_get_info(char *buffer, char **start, off_t offset, int length)
 623 {
 624         int len;
 625
 626         read_lock_bh(&queue_lock);
 627
 628         len = sprintf(buffer,
 629                       "Peer PID          : %d\n"
 630                       "Copy mode         : %hu\n"
 631                       "Copy range        : %u\n"
 632                       "Queue length      : %u\n"
 633                       "Queue max. length : %u\n"
 634                       "Queue dropped     : %u\n"
 635                       "Netfilter dropped : %u\n",
 636                       peer_pid,
 637                       copy_mode,
 638                       copy_range,
 639                       queue_total,
 640                       queue_maxlen,
 641                       queue_dropped,
 642                       queue_user_dropped);
 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 struct nf_queue_handler nfqh = {
 656         .name   = "ip6_queue",
 657         .outfn  = &ipq_enqueue_packet,
 658 };
 659
 660 static int
 661 init_or_cleanup(int init)
 662 {
 663         int status = -ENOMEM;
 664         struct proc_dir_entry *proc;
 665
 666         if (!init)
 667                 goto cleanup;
 668
 669         netlink_register_notifier(&ipq_nl_notifier);
 670         ipqnl = netlink_kernel_create(NETLINK_IP6_FW, 0, ipq_rcv_sk,
 671                                       THIS_MODULE);
 672         if (ipqnl == NULL) {
 673                 printk(KERN_ERR "ip6_queue: failed to create netlink socket\n");
 674                 goto cleanup_netlink_notifier;
 675         }
 676
 677         proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
 678         if (proc)
 679                 proc->owner = THIS_MODULE;
 680         else {
 681                 printk(KERN_ERR "ip6_queue: failed to create proc entry\n");
 682                 goto cleanup_ipqnl;
 683         }
 684
 685         register_netdevice_notifier(&ipq_dev_notifier);
 686         ipq_sysctl_header = register_sysctl_table(ipq_root_table, 0);
 687
 688         status = nf_register_queue_handler(PF_INET6, &nfqh);
 689         if (status < 0) {
 690                 printk(KERN_ERR "ip6_queue: failed to register queue handler\n");
 691                 goto cleanup_sysctl;
 692         }
 693         return status;
 694
 695 cleanup:
 696         nf_unregister_queue_handlers(&nfqh);
 697         synchronize_net();
 698         ipq_flush(NF_DROP);
 699
 700 cleanup_sysctl:
 701         unregister_sysctl_table(ipq_sysctl_header);
 702         unregister_netdevice_notifier(&ipq_dev_notifier);
 703         proc_net_remove(IPQ_PROC_FS_NAME);
 704
 705 cleanup_ipqnl:
 706         sock_release(ipqnl->sk_socket);
 707         down(&ipqnl_sem);
 708         up(&ipqnl_sem);
 709
 710 cleanup_netlink_notifier:
 711         netlink_unregister_notifier(&ipq_nl_notifier);
 712         return status;
 713 }
 714
 715 static int __init init(void)
 716 {
 717
 718         return init_or_cleanup(1);
 719 }
 720
 721 static void __exit fini(void)
 722 {
 723         init_or_cleanup(0);
 724 }
 725
 726 MODULE_DESCRIPTION("IPv6 packet queue handler");
 727 MODULE_LICENSE("GPL");
 728
 729 module_init(init);
 730 module_exit(fini);