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 DEFINE_RWLOCK(queue_lock);
  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         net_disable_timestamp();
 171         __ipq_set_mode(IPQ_COPY_NONE, 0);
 172         __ipq_flush(NF_DROP);
 173 }
 174
 175 static struct ipq_queue_entry *
 176 ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 177 {
 178         struct ipq_queue_entry *entry;
 179
 180         write_lock_bh(&queue_lock);
 181         entry = __ipq_find_dequeue_entry(cmpfn, data);
 182         write_unlock_bh(&queue_lock);
 183         return entry;
 184 }
 185
 186 static void
 187 ipq_flush(int verdict)
 188 {
 189         write_lock_bh(&queue_lock);
 190         __ipq_flush(verdict);
 191         write_unlock_bh(&queue_lock);
 192 }
 193
 194 static struct sk_buff *
 195 ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
 196 {
 197         unsigned char *old_tail;
 198         size_t size = 0;
 199         size_t data_len = 0;
 200         struct sk_buff *skb;
 201         struct ipq_packet_msg *pmsg;
 202         struct nlmsghdr *nlh;
 203
 204         read_lock_bh(&queue_lock);
 205
 206         switch (copy_mode) {
 207         case IPQ_COPY_META:
 208         case IPQ_COPY_NONE:
 209                 size = NLMSG_SPACE(sizeof(*pmsg));
 210                 data_len = 0;
 211                 break;
 212
 213         case IPQ_COPY_PACKET:
 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->stamp.tv_sec;
 242         pmsg->timestamp_usec  = entry->skb->stamp.tv_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, void *data)
 282 {
 283         int status = -EINVAL;
 284         struct sk_buff *nskb;
 285         struct ipq_queue_entry *entry;
 286
 287         if (copy_mode == IPQ_COPY_NONE)
 288                 return -EAGAIN;
 289
 290         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 291         if (entry == NULL) {
 292                 printk(KERN_ERR "ip6_queue: OOM in ipq_enqueue_packet()\n");
 293                 return -ENOMEM;
 294         }
 295
 296         entry->info = info;
 297         entry->skb = skb;
 298
 299         if (entry->info->hook == NF_IP_LOCAL_OUT) {
 300                 struct ipv6hdr *iph = skb->nh.ipv6h;
 301
 302                 entry->rt_info.daddr = iph->daddr;
 303                 entry->rt_info.saddr = iph->saddr;
 304         }
 305
 306         nskb = ipq_build_packet_message(entry, &status);
 307         if (nskb == NULL)
 308                 goto err_out_free;
 309
 310         write_lock_bh(&queue_lock);
 311
 312         if (!peer_pid)
 313                 goto err_out_free_nskb;
 314
 315         /* netlink_unicast will either free the nskb or attach it to a socket */
 316         status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
 317         if (status < 0)
 318                 goto err_out_unlock;
 319
 320         status = __ipq_enqueue_entry(entry);
 321         if (status < 0)
 322                 goto err_out_unlock;
 323
 324         write_unlock_bh(&queue_lock);
 325         return status;
 326
 327 err_out_free_nskb:
 328         kfree_skb(nskb);
 329
 330 err_out_unlock:
 331         write_unlock_bh(&queue_lock);
 332
 333 err_out_free:
 334         kfree(entry);
 335         return status;
 336 }
 337
 338 static int
 339 ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
 340 {
 341         int diff;
 342         struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload;
 343
 344         if (v->data_len < sizeof(*user_iph))
 345                 return 0;
 346         diff = v->data_len - e->skb->len;
 347         if (diff < 0)
 348                 skb_trim(e->skb, v->data_len);
 349         else if (diff > 0) {
 350                 if (v->data_len > 0xFFFF)
 351                         return -EINVAL;
 352                 if (diff > skb_tailroom(e->skb)) {
 353                         struct sk_buff *newskb;
 354
 355                         newskb = skb_copy_expand(e->skb,
 356                                                  skb_headroom(e->skb),
 357                                                  diff,
 358                                                  GFP_ATOMIC);
 359                         if (newskb == NULL) {
 360                                 printk(KERN_WARNING "ip6_queue: OOM "
 361                                       "in mangle, dropping packet\n");
 362                                 return -ENOMEM;
 363                         }
 364                         if (e->skb->sk)
 365                                 skb_set_owner_w(newskb, e->skb->sk);
 366                         kfree_skb(e->skb);
 367                         e->skb = newskb;
 368                 }
 369                 skb_put(e->skb, diff);
 370         }
 371         if (!skb_ip_make_writable(&e->skb, v->data_len))
 372                 return -ENOMEM;
 373         memcpy(e->skb->data, v->payload, v->data_len);
 374         e->skb->nfcache |= NFC_ALTERED;
 375
 376         /*
 377          * Extra routing may needed on local out, as the QUEUE target never
 378          * returns control to the table.
 379          * Not a nice way to cmp, but works
 380          */
 381         if (e->info->hook == NF_IP_LOCAL_OUT) {
 382                 struct ipv6hdr *iph = e->skb->nh.ipv6h;
 383                 if (!ipv6_addr_equal(&iph->daddr, &e->rt_info.daddr) ||
 384                     !ipv6_addr_equal(&iph->saddr, &e->rt_info.saddr))
 385                         return ip6_route_me_harder(e->skb);
 386         }
 387         return 0;
 388 }
 389
 390 static inline int
 391 id_cmp(struct ipq_queue_entry *e, unsigned long id)
 392 {
 393         return (id == (unsigned long )e);
 394 }
 395
 396 static int
 397 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
 398 {
 399         struct ipq_queue_entry *entry;
 400
 401         if (vmsg->value > NF_MAX_VERDICT)
 402                 return -EINVAL;
 403
 404         entry = ipq_find_dequeue_entry(id_cmp, vmsg->id);
 405         if (entry == NULL)
 406                 return -ENOENT;
 407         else {
 408                 int verdict = vmsg->value;
 409
 410                 if (vmsg->data_len && vmsg->data_len == len)
 411                         if (ipq_mangle_ipv6(vmsg, entry) < 0)
 412                                 verdict = NF_DROP;
 413
 414                 ipq_issue_verdict(entry, verdict);
 415                 return 0;
 416         }
 417 }
 418
 419 static int
 420 ipq_set_mode(unsigned char mode, unsigned int range)
 421 {
 422         int status;
 423
 424         write_lock_bh(&queue_lock);
 425         status = __ipq_set_mode(mode, range);
 426         write_unlock_bh(&queue_lock);
 427         return status;
 428 }
 429
 430 static int
 431 ipq_receive_peer(struct ipq_peer_msg *pmsg,
 432                  unsigned char type, unsigned int len)
 433 {
 434         int status = 0;
 435
 436         if (len < sizeof(*pmsg))
 437                 return -EINVAL;
 438
 439         switch (type) {
 440         case IPQM_MODE:
 441                 status = ipq_set_mode(pmsg->msg.mode.value,
 442                                       pmsg->msg.mode.range);
 443                 break;
 444
 445         case IPQM_VERDICT:
 446                 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
 447                         status = -EINVAL;
 448                 else
 449                         status = ipq_set_verdict(&pmsg->msg.verdict,
 450                                                  len - sizeof(*pmsg));
 451                         break;
 452         default:
 453                 status = -EINVAL;
 454         }
 455         return status;
 456 }
 457
 458 static int
 459 dev_cmp(struct ipq_queue_entry *entry, unsigned long ifindex)
 460 {
 461         if (entry->info->indev)
 462                 if (entry->info->indev->ifindex == ifindex)
 463                         return 1;
 464
 465         if (entry->info->outdev)
 466                 if (entry->info->outdev->ifindex == ifindex)
 467                         return 1;
 468
 469         return 0;
 470 }
 471
 472 static void
 473 ipq_dev_drop(int ifindex)
 474 {
 475         struct ipq_queue_entry *entry;
 476
 477         while ((entry = ipq_find_dequeue_entry(dev_cmp, ifindex)) != NULL)
 478                 ipq_issue_verdict(entry, NF_DROP);
 479 }
 480
 481 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 482
 483 static inline void
 484 ipq_rcv_skb(struct sk_buff *skb)
 485 {
 486         int status, type, pid, flags, nlmsglen, skblen;
 487         struct nlmsghdr *nlh;
 488
 489         skblen = skb->len;
 490         if (skblen < sizeof(*nlh))
 491                 return;
 492
 493         nlh = (struct nlmsghdr *)skb->data;
 494         nlmsglen = nlh->nlmsg_len;
 495         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
 496                 return;
 497
 498         pid = nlh->nlmsg_pid;
 499         flags = nlh->nlmsg_flags;
 500
 501         if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
 502                 RCV_SKB_FAIL(-EINVAL);
 503
 504         if (flags & MSG_TRUNC)
 505                 RCV_SKB_FAIL(-ECOMM);
 506
 507         type = nlh->nlmsg_type;
 508         if (type < NLMSG_NOOP || type >= IPQM_MAX)
 509                 RCV_SKB_FAIL(-EINVAL);
 510
 511         if (type <= IPQM_BASE)
 512                 return;
 513
 514         if (security_netlink_recv(skb))
 515                 RCV_SKB_FAIL(-EPERM);
 516
 517         write_lock_bh(&queue_lock);
 518
 519         if (peer_pid) {
 520                 if (peer_pid != pid) {
 521                         write_unlock_bh(&queue_lock);
 522                         RCV_SKB_FAIL(-EBUSY);
 523                 }
 524         } else {
 525                 net_enable_timestamp();
 526                 peer_pid = pid;
 527         }
 528
 529         write_unlock_bh(&queue_lock);
 530
 531         status = ipq_receive_peer(NLMSG_DATA(nlh), type,
 532                                   skblen - NLMSG_LENGTH(0));
 533         if (status < 0)
 534                 RCV_SKB_FAIL(status);
 535
 536         if (flags & NLM_F_ACK)
 537                 netlink_ack(skb, nlh, 0);
 538         return;
 539 }
 540
 541 static void
 542 ipq_rcv_sk(struct sock *sk, int len)
 543 {
 544         do {
 545                 struct sk_buff *skb;
 546
 547                 if (down_trylock(&ipqnl_sem))
 548                         return;
 549
 550                 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
 551                         ipq_rcv_skb(skb);
 552                         kfree_skb(skb);
 553                 }
 554
 555                 up(&ipqnl_sem);
 556
 557         } while (ipqnl && ipqnl->sk_receive_queue.qlen);
 558 }
 559
 560 static int
 561 ipq_rcv_dev_event(struct notifier_block *this,
 562                   unsigned long event, void *ptr)
 563 {
 564         struct net_device *dev = ptr;
 565
 566         /* Drop any packets associated with the downed device */
 567         if (event == NETDEV_DOWN)
 568                 ipq_dev_drop(dev->ifindex);
 569         return NOTIFY_DONE;
 570 }
 571
 572 static struct notifier_block ipq_dev_notifier = {
 573         .notifier_call  = ipq_rcv_dev_event,
 574 };
 575
 576 static int
 577 ipq_rcv_nl_event(struct notifier_block *this,
 578                  unsigned long event, void *ptr)
 579 {
 580         struct netlink_notify *n = ptr;
 581
 582         if (event == NETLINK_URELEASE &&
 583             n->protocol == NETLINK_IP6_FW && n->pid) {
 584                 write_lock_bh(&queue_lock);
 585                 if (n->pid == peer_pid)
 586                         __ipq_reset();
 587                 write_unlock_bh(&queue_lock);
 588         }
 589         return NOTIFY_DONE;
 590 }
 591
 592 static struct notifier_block ipq_nl_notifier = {
 593         .notifier_call  = ipq_rcv_nl_event,
 594 };
 595
 596 static struct ctl_table_header *ipq_sysctl_header;
 597
 598 static ctl_table ipq_table[] = {
 599         {
 600                 .ctl_name       = NET_IPQ_QMAX,
 601                 .procname       = NET_IPQ_QMAX_NAME,
 602                 .data           = &queue_maxlen,
 603                 .maxlen         = sizeof(queue_maxlen),
 604                 .mode           = 0644,
 605                 .proc_handler   = proc_dointvec
 606         },
 607         { .ctl_name = 0 }
 608 };
 609
 610 static ctl_table ipq_dir_table[] = {
 611         {
 612                 .ctl_name       = NET_IPV6,
 613                 .procname       = "ipv6",
 614                 .mode           = 0555,
 615                 .child          = ipq_table
 616         },
 617         { .ctl_name = 0 }
 618 };
 619
 620 static ctl_table ipq_root_table[] = {
 621         {
 622                 .ctl_name       = CTL_NET,
 623                 .procname       = "net",
 624                 .mode           = 0555,
 625                 .child          = ipq_dir_table
 626         },
 627         { .ctl_name = 0 }
 628 };
 629
 630 static int
 631 ipq_get_info(char *buffer, char **start, off_t offset, int length)
 632 {
 633         int len;
 634
 635         read_lock_bh(&queue_lock);
 636
 637         len = sprintf(buffer,
 638                       "Peer PID          : %d\n"
 639                       "Copy mode         : %hu\n"
 640                       "Copy range        : %u\n"
 641                       "Queue length      : %u\n"
 642                       "Queue max. length : %u\n",
 643                       peer_pid,
 644                       copy_mode,
 645                       copy_range,
 646                       queue_total,
 647                       queue_maxlen);
 648
 649         read_unlock_bh(&queue_lock);
 650
 651         *start = buffer + offset;
 652         len -= offset;
 653         if (len > length)
 654                 len = length;
 655         else if (len < 0)
 656                 len = 0;
 657         return len;
 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, ipq_rcv_sk);
 671         if (ipqnl == NULL) {
 672                 printk(KERN_ERR "ip6_queue: failed to create netlink socket\n");
 673                 goto cleanup_netlink_notifier;
 674         }
 675
 676         proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
 677         if (proc)
 678                 proc->owner = THIS_MODULE;
 679         else {
 680                 printk(KERN_ERR "ip6_queue: failed to create proc entry\n");
 681                 goto cleanup_ipqnl;
 682         }
 683
 684         register_netdevice_notifier(&ipq_dev_notifier);
 685         ipq_sysctl_header = register_sysctl_table(ipq_root_table, 0);
 686
 687         status = nf_register_queue_handler(PF_INET6, ipq_enqueue_packet, NULL);
 688         if (status < 0) {
 689                 printk(KERN_ERR "ip6_queue: failed to register queue handler\n");
 690                 goto cleanup_sysctl;
 691         }
 692         return status;
 693
 694 cleanup:
 695         nf_unregister_queue_handler(PF_INET6);
 696         synchronize_net();
 697         ipq_flush(NF_DROP);
 698
 699 cleanup_sysctl:
 700         unregister_sysctl_table(ipq_sysctl_header);
 701         unregister_netdevice_notifier(&ipq_dev_notifier);
 702         proc_net_remove(IPQ_PROC_FS_NAME);
 703
 704 cleanup_ipqnl:
 705         sock_release(ipqnl->sk_socket);
 706         down(&ipqnl_sem);
 707         up(&ipqnl_sem);
 708
 709 cleanup_netlink_notifier:
 710         netlink_unregister_notifier(&ipq_nl_notifier);
 711         return status;
 712 }
 713
 714 static int __init init(void)
 715 {
 716
 717         return init_or_cleanup(1);
 718 }
 719
 720 static void __exit fini(void)
 721 {
 722         init_or_cleanup(0);
 723 }
 724
 725 MODULE_DESCRIPTION("IPv6 packet queue handler");
 726 MODULE_LICENSE("GPL");
 727
 728 module_init(init);
 729 module_exit(fini);