net/ipv4/netfilter/ip_queue.c

   1 /*
   2  * This is a module which is used for queueing IPv4 packets and
   3  * communicating with userspace via netlink.
   4  *
   5  * (C) 2000-2002 James Morris <jmorris@intercode.com.au>
   6  * (C) 2003-2005 Netfilter Core Team <coreteam@netfilter.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * 2000-03-27: Simplified code (thanks to Andi Kleen for clues).
  13  * 2000-05-20: Fixed notifier problems (following Miguel Freitas' report).
  14  * 2000-06-19: Fixed so nfmark is copied to metadata (reported by Sebastian
  15  *             Zander).
  16  * 2000-08-01: Added Nick Williams' MAC support.
  17  * 2002-06-25: Code cleanup.
  18  * 2005-01-10: Added /proc counter for dropped packets; fixed so
  19  *             packets aren't delivered to user space if they're going
  20  *             to be dropped.
  21  * 2005-05-26: local_bh_{disable,enable} around nf_reinject (Harald Welte)
  22  *
  23  */
  24 #include <linux/module.h>
  25 #include <linux/skbuff.h>
  26 #include <linux/init.h>
  27 #include <linux/ip.h>
  28 #include <linux/notifier.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/netfilter.h>
  31 #include <linux/netfilter_ipv4/ip_queue.h>
  32 #include <linux/netfilter_ipv4/ip_tables.h>
  33 #include <linux/netlink.h>
  34 #include <linux/spinlock.h>
  35 #include <linux/sysctl.h>
  36 #include <linux/proc_fs.h>
  37 #include <linux/security.h>
  38 #include <linux/mutex.h>
  39 #include <net/sock.h>
  40 #include <net/route.h>
  41
  42 #define IPQ_QMAX_DEFAULT 1024
  43 #define IPQ_PROC_FS_NAME "ip_queue"
  44 #define NET_IPQ_QMAX 2088
  45 #define NET_IPQ_QMAX_NAME "ip_queue_maxlen"
  46
  47 struct ipq_queue_entry {
  48         struct list_head list;
  49         struct nf_info *info;
  50         struct sk_buff *skb;
  51 };
  52
  53 typedef int (*ipq_cmpfn)(struct ipq_queue_entry *, unsigned long);
  54
  55 static unsigned char copy_mode = IPQ_COPY_NONE;
  56 static unsigned int queue_maxlen = IPQ_QMAX_DEFAULT;
  57 static DEFINE_RWLOCK(queue_lock);
  58 static int peer_pid;
  59 static unsigned int copy_range;
  60 static unsigned int queue_total;
  61 static unsigned int queue_dropped = 0;
  62 static unsigned int queue_user_dropped = 0;
  63 static struct sock *ipqnl;
  64 static LIST_HEAD(queue_list);
  65 static DEFINE_MUTEX(ipqnl_mutex);
  66
  67 static void
  68 ipq_issue_verdict(struct ipq_queue_entry *entry, int verdict)
  69 {
  70         /* TCP input path (and probably other bits) assume to be called
  71          * from softirq context, not from syscall, like ipq_issue_verdict is
  72          * called.  TCP input path deadlocks with locks taken from timer
  73          * softirq, e.g.  We therefore emulate this by local_bh_disable() */
  74
  75         local_bh_disable();
  76         nf_reinject(entry->skb, entry->info, verdict);
  77         local_bh_enable();
  78
  79         kfree(entry);
  80 }
  81
  82 static inline void
  83 __ipq_enqueue_entry(struct ipq_queue_entry *entry)
  84 {
  85        list_add(&entry->list, &queue_list);
  86        queue_total++;
  87 }
  88
  89 /*
  90  * Find and return a queued entry matched by cmpfn, or return the last
  91  * entry if cmpfn is NULL.
  92  */
  93 static inline struct ipq_queue_entry *
  94 __ipq_find_entry(ipq_cmpfn cmpfn, unsigned long data)
  95 {
  96         struct list_head *p;
  97
  98         list_for_each_prev(p, &queue_list) {
  99                 struct ipq_queue_entry *entry = (struct ipq_queue_entry *)p;
 100
 101                 if (!cmpfn || cmpfn(entry, data))
 102                         return entry;
 103         }
 104         return NULL;
 105 }
 106
 107 static inline void
 108 __ipq_dequeue_entry(struct ipq_queue_entry *entry)
 109 {
 110         list_del(&entry->list);
 111         queue_total--;
 112 }
 113
 114 static inline struct ipq_queue_entry *
 115 __ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 116 {
 117         struct ipq_queue_entry *entry;
 118
 119         entry = __ipq_find_entry(cmpfn, data);
 120         if (entry == NULL)
 121                 return NULL;
 122
 123         __ipq_dequeue_entry(entry);
 124         return entry;
 125 }
 126
 127
 128 static inline void
 129 __ipq_flush(int verdict)
 130 {
 131         struct ipq_queue_entry *entry;
 132
 133         while ((entry = __ipq_find_dequeue_entry(NULL, 0)))
 134                 ipq_issue_verdict(entry, verdict);
 135 }
 136
 137 static inline int
 138 __ipq_set_mode(unsigned char mode, unsigned int range)
 139 {
 140         int status = 0;
 141
 142         switch(mode) {
 143         case IPQ_COPY_NONE:
 144         case IPQ_COPY_META:
 145                 copy_mode = mode;
 146                 copy_range = 0;
 147                 break;
 148
 149         case IPQ_COPY_PACKET:
 150                 copy_mode = mode;
 151                 copy_range = range;
 152                 if (copy_range > 0xFFFF)
 153                         copy_range = 0xFFFF;
 154                 break;
 155
 156         default:
 157                 status = -EINVAL;
 158
 159         }
 160         return status;
 161 }
 162
 163 static inline void
 164 __ipq_reset(void)
 165 {
 166         peer_pid = 0;
 167         net_disable_timestamp();
 168         __ipq_set_mode(IPQ_COPY_NONE, 0);
 169         __ipq_flush(NF_DROP);
 170 }
 171
 172 static struct ipq_queue_entry *
 173 ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 174 {
 175         struct ipq_queue_entry *entry;
 176
 177         write_lock_bh(&queue_lock);
 178         entry = __ipq_find_dequeue_entry(cmpfn, data);
 179         write_unlock_bh(&queue_lock);
 180         return entry;
 181 }
 182
 183 static void
 184 ipq_flush(int verdict)
 185 {
 186         write_lock_bh(&queue_lock);
 187         __ipq_flush(verdict);
 188         write_unlock_bh(&queue_lock);
 189 }
 190
 191 static struct sk_buff *
 192 ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
 193 {
 194         unsigned char *old_tail;
 195         size_t size = 0;
 196         size_t data_len = 0;
 197         struct sk_buff *skb;
 198         struct ipq_packet_msg *pmsg;
 199         struct nlmsghdr *nlh;
 200
 201         read_lock_bh(&queue_lock);
 202
 203         switch (copy_mode) {
 204         case IPQ_COPY_META:
 205         case IPQ_COPY_NONE:
 206                 size = NLMSG_SPACE(sizeof(*pmsg));
 207                 data_len = 0;
 208                 break;
 209
 210         case IPQ_COPY_PACKET:
 211                 if (entry->skb->ip_summed == CHECKSUM_HW &&
 212                     (*errp = skb_checksum_help(entry->skb,
 213                                                entry->info->outdev == NULL))) {
 214                         read_unlock_bh(&queue_lock);
 215                         return NULL;
 216                 }
 217                 if (copy_range == 0 || copy_range > entry->skb->len)
 218                         data_len = entry->skb->len;
 219                 else
 220                         data_len = copy_range;
 221
 222                 size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
 223                 break;
 224
 225         default:
 226                 *errp = -EINVAL;
 227                 read_unlock_bh(&queue_lock);
 228                 return NULL;
 229         }
 230
 231         read_unlock_bh(&queue_lock);
 232
 233         skb = alloc_skb(size, GFP_ATOMIC);
 234         if (!skb)
 235                 goto nlmsg_failure;
 236
 237         old_tail= skb->tail;
 238         nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
 239         pmsg = NLMSG_DATA(nlh);
 240         memset(pmsg, 0, sizeof(*pmsg));
 241
 242         pmsg->packet_id       = (unsigned long )entry;
 243         pmsg->data_len        = data_len;
 244         pmsg->timestamp_sec   = entry->skb->tstamp.off_sec;
 245         pmsg->timestamp_usec  = entry->skb->tstamp.off_usec;
 246         pmsg->mark            = entry->skb->nfmark;
 247         pmsg->hook            = entry->info->hook;
 248         pmsg->hw_protocol     = entry->skb->protocol;
 249
 250         if (entry->info->indev)
 251                 strcpy(pmsg->indev_name, entry->info->indev->name);
 252         else
 253                 pmsg->indev_name[0] = '\0';
 254
 255         if (entry->info->outdev)
 256                 strcpy(pmsg->outdev_name, entry->info->outdev->name);
 257         else
 258                 pmsg->outdev_name[0] = '\0';
 259
 260         if (entry->info->indev && entry->skb->dev) {
 261                 pmsg->hw_type = entry->skb->dev->type;
 262                 if (entry->skb->dev->hard_header_parse)
 263                         pmsg->hw_addrlen =
 264                                 entry->skb->dev->hard_header_parse(entry->skb,
 265                                                                    pmsg->hw_addr);
 266         }
 267
 268         if (data_len)
 269                 if (skb_copy_bits(entry->skb, 0, pmsg->payload, data_len))
 270                         BUG();
 271
 272         nlh->nlmsg_len = skb->tail - old_tail;
 273         return skb;
 274
 275 nlmsg_failure:
 276         if (skb)
 277                 kfree_skb(skb);
 278         *errp = -EINVAL;
 279         printk(KERN_ERR "ip_queue: error creating packet message\n");
 280         return NULL;
 281 }
 282
 283 static int
 284 ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info,
 285                    unsigned int queuenum, void *data)
 286 {
 287         int status = -EINVAL;
 288         struct sk_buff *nskb;
 289         struct ipq_queue_entry *entry;
 290
 291         if (copy_mode == IPQ_COPY_NONE)
 292                 return -EAGAIN;
 293
 294         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 295         if (entry == NULL) {
 296                 printk(KERN_ERR "ip_queue: OOM in ipq_enqueue_packet()\n");
 297                 return -ENOMEM;
 298         }
 299
 300         entry->info = info;
 301         entry->skb = skb;
 302
 303         nskb = ipq_build_packet_message(entry, &status);
 304         if (nskb == NULL)
 305                 goto err_out_free;
 306
 307         write_lock_bh(&queue_lock);
 308
 309         if (!peer_pid)
 310                 goto err_out_free_nskb;
 311
 312         if (queue_total >= queue_maxlen) {
 313                 queue_dropped++;
 314                 status = -ENOSPC;
 315                 if (net_ratelimit())
 316                           printk (KERN_WARNING "ip_queue: full at %d entries, "
 317                                   "dropping packets(s). Dropped: %d\n", queue_total,
 318                                   queue_dropped);
 319                 goto err_out_free_nskb;
 320         }
 321
 322         /* netlink_unicast will either free the nskb or attach it to a socket */
 323         status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
 324         if (status < 0) {
 325                 queue_user_dropped++;
 326                 goto err_out_unlock;
 327         }
 328
 329         __ipq_enqueue_entry(entry);
 330
 331         write_unlock_bh(&queue_lock);
 332         return status;
 333
 334 err_out_free_nskb:
 335         kfree_skb(nskb);
 336
 337 err_out_unlock:
 338         write_unlock_bh(&queue_lock);
 339
 340 err_out_free:
 341         kfree(entry);
 342         return status;
 343 }
 344
 345 static int
 346 ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
 347 {
 348         int diff;
 349         struct iphdr *user_iph = (struct iphdr *)v->payload;
 350
 351         if (v->data_len < sizeof(*user_iph))
 352                 return 0;
 353         diff = v->data_len - e->skb->len;
 354         if (diff < 0)
 355                 skb_trim(e->skb, v->data_len);
 356         else if (diff > 0) {
 357                 if (v->data_len > 0xFFFF)
 358                         return -EINVAL;
 359                 if (diff > skb_tailroom(e->skb)) {
 360                         struct sk_buff *newskb;
 361
 362                         newskb = skb_copy_expand(e->skb,
 363                                                  skb_headroom(e->skb),
 364                                                  diff,
 365                                                  GFP_ATOMIC);
 366                         if (newskb == NULL) {
 367                                 printk(KERN_WARNING "ip_queue: OOM "
 368                                       "in mangle, dropping packet\n");
 369                                 return -ENOMEM;
 370                         }
 371                         if (e->skb->sk)
 372                                 skb_set_owner_w(newskb, e->skb->sk);
 373                         kfree_skb(e->skb);
 374                         e->skb = newskb;
 375                 }
 376                 skb_put(e->skb, diff);
 377         }
 378         if (!skb_make_writable(&e->skb, v->data_len))
 379                 return -ENOMEM;
 380         memcpy(e->skb->data, v->payload, v->data_len);
 381         e->skb->ip_summed = CHECKSUM_NONE;
 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_ipv4(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         } else {
 521                 net_enable_timestamp();
 522                 peer_pid = pid;
 523         }
 524
 525         write_unlock_bh(&queue_lock);
 526
 527         status = ipq_receive_peer(NLMSG_DATA(nlh), type,
 528                                   nlmsglen - NLMSG_LENGTH(0));
 529         if (status < 0)
 530                 RCV_SKB_FAIL(status);
 531
 532         if (flags & NLM_F_ACK)
 533                 netlink_ack(skb, nlh, 0);
 534         return;
 535 }
 536
 537 static void
 538 ipq_rcv_sk(struct sock *sk, int len)
 539 {
 540         struct sk_buff *skb;
 541         unsigned int qlen;
 542
 543         mutex_lock(&ipqnl_mutex);
 544
 545         for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
 546                 skb = skb_dequeue(&sk->sk_receive_queue);
 547                 ipq_rcv_skb(skb);
 548                 kfree_skb(skb);
 549         }
 550
 551         mutex_unlock(&ipqnl_mutex);
 552 }
 553
 554 static int
 555 ipq_rcv_dev_event(struct notifier_block *this,
 556                   unsigned long event, void *ptr)
 557 {
 558         struct net_device *dev = ptr;
 559
 560         /* Drop any packets associated with the downed device */
 561         if (event == NETDEV_DOWN)
 562                 ipq_dev_drop(dev->ifindex);
 563         return NOTIFY_DONE;
 564 }
 565
 566 static struct notifier_block ipq_dev_notifier = {
 567         .notifier_call  = ipq_rcv_dev_event,
 568 };
 569
 570 static int
 571 ipq_rcv_nl_event(struct notifier_block *this,
 572                  unsigned long event, void *ptr)
 573 {
 574         struct netlink_notify *n = ptr;
 575
 576         if (event == NETLINK_URELEASE &&
 577             n->protocol == NETLINK_FIREWALL && n->pid) {
 578                 write_lock_bh(&queue_lock);
 579                 if (n->pid == peer_pid)
 580                         __ipq_reset();
 581                 write_unlock_bh(&queue_lock);
 582         }
 583         return NOTIFY_DONE;
 584 }
 585
 586 static struct notifier_block ipq_nl_notifier = {
 587         .notifier_call  = ipq_rcv_nl_event,
 588 };
 589
 590 static struct ctl_table_header *ipq_sysctl_header;
 591
 592 static ctl_table ipq_table[] = {
 593         {
 594                 .ctl_name       = NET_IPQ_QMAX,
 595                 .procname       = NET_IPQ_QMAX_NAME,
 596                 .data           = &queue_maxlen,
 597                 .maxlen         = sizeof(queue_maxlen),
 598                 .mode           = 0644,
 599                 .proc_handler   = proc_dointvec
 600         },
 601         { .ctl_name = 0 }
 602 };
 603
 604 static ctl_table ipq_dir_table[] = {
 605         {
 606                 .ctl_name       = NET_IPV4,
 607                 .procname       = "ipv4",
 608                 .mode           = 0555,
 609                 .child          = ipq_table
 610         },
 611         { .ctl_name = 0 }
 612 };
 613
 614 static ctl_table ipq_root_table[] = {
 615         {
 616                 .ctl_name       = CTL_NET,
 617                 .procname       = "net",
 618                 .mode           = 0555,
 619                 .child          = ipq_dir_table
 620         },
 621         { .ctl_name = 0 }
 622 };
 623
 624 #ifdef CONFIG_PROC_FS
 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                       "Queue dropped     : %u\n"
 639                       "Netlink dropped   : %u\n",
 640                       peer_pid,
 641                       copy_mode,
 642                       copy_range,
 643                       queue_total,
 644                       queue_maxlen,
 645                       queue_dropped,
 646                       queue_user_dropped);
 647
 648         read_unlock_bh(&queue_lock);
 649
 650         *start = buffer + offset;
 651         len -= offset;
 652         if (len > length)
 653                 len = length;
 654         else if (len < 0)
 655                 len = 0;
 656         return len;
 657 }
 658 #endif /* CONFIG_PROC_FS */
 659
 660 static struct nf_queue_handler nfqh = {
 661         .name   = "ip_queue",
 662         .outfn  = &ipq_enqueue_packet,
 663 };
 664
 665 static int __init ip_queue_init(void)
 666 {
 667         int status = -ENOMEM;
 668         struct proc_dir_entry *proc;
 669
 670         netlink_register_notifier(&ipq_nl_notifier);
 671         ipqnl = netlink_kernel_create(NETLINK_FIREWALL, 0, ipq_rcv_sk,
 672                                       THIS_MODULE);
 673         if (ipqnl == NULL) {
 674                 printk(KERN_ERR "ip_queue: failed to create netlink socket\n");
 675                 goto cleanup_netlink_notifier;
 676         }
 677
 678         proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
 679         if (proc)
 680                 proc->owner = THIS_MODULE;
 681         else {
 682                 printk(KERN_ERR "ip_queue: failed to create proc entry\n");
 683                 goto cleanup_ipqnl;
 684         }
 685
 686         register_netdevice_notifier(&ipq_dev_notifier);
 687         ipq_sysctl_header = register_sysctl_table(ipq_root_table, 0);
 688
 689         status = nf_register_queue_handler(PF_INET, &nfqh);
 690         if (status < 0) {
 691                 printk(KERN_ERR "ip_queue: failed to register queue handler\n");
 692                 goto cleanup_sysctl;
 693         }
 694         return status;
 695
 696 cleanup_sysctl:
 697         unregister_sysctl_table(ipq_sysctl_header);
 698         unregister_netdevice_notifier(&ipq_dev_notifier);
 699         proc_net_remove(IPQ_PROC_FS_NAME);
 700
 701 cleanup_ipqnl:
 702         sock_release(ipqnl->sk_socket);
 703         mutex_lock(&ipqnl_mutex);
 704         mutex_unlock(&ipqnl_mutex);
 705
 706 cleanup_netlink_notifier:
 707         netlink_unregister_notifier(&ipq_nl_notifier);
 708         return status;
 709 }
 710
 711 static void __exit ip_queue_fini(void)
 712 {
 713         nf_unregister_queue_handlers(&nfqh);
 714         synchronize_net();
 715         ipq_flush(NF_DROP);
 716
 717         unregister_sysctl_table(ipq_sysctl_header);
 718         unregister_netdevice_notifier(&ipq_dev_notifier);
 719         proc_net_remove(IPQ_PROC_FS_NAME);
 720
 721         sock_release(ipqnl->sk_socket);
 722         mutex_lock(&ipqnl_mutex);
 723         mutex_unlock(&ipqnl_mutex);
 724
 725         netlink_unregister_notifier(&ipq_nl_notifier);
 726 }
 727
 728 MODULE_DESCRIPTION("IPv4 packet queue handler");
 729 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
 730 MODULE_LICENSE("GPL");
 731
 732 module_init(ip_queue_init);
 733 module_exit(ip_queue_fini);