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 <net/sock.h>
  39 #include <net/route.h>
  40
  41 #define IPQ_QMAX_DEFAULT 1024
  42 #define IPQ_PROC_FS_NAME "ip_queue"
  43 #define NET_IPQ_QMAX 2088
  44 #define NET_IPQ_QMAX_NAME "ip_queue_maxlen"
  45
  46 struct ipq_queue_entry {
  47         struct list_head list;
  48         struct nf_info *info;
  49         struct sk_buff *skb;
  50 };
  51
  52 typedef int (*ipq_cmpfn)(struct ipq_queue_entry *, unsigned long);
  53
  54 static unsigned char copy_mode = IPQ_COPY_NONE;
  55 static unsigned int queue_maxlen = IPQ_QMAX_DEFAULT;
  56 static DEFINE_RWLOCK(queue_lock);
  57 static int peer_pid;
  58 static unsigned int copy_range;
  59 static unsigned int queue_total;
  60 static unsigned int queue_dropped = 0;
  61 static unsigned int queue_user_dropped = 0;
  62 static struct sock *ipqnl;
  63 static LIST_HEAD(queue_list);
  64 static DECLARE_MUTEX(ipqnl_sem);
  65
  66 static void
  67 ipq_issue_verdict(struct ipq_queue_entry *entry, int verdict)
  68 {
  69         /* TCP input path (and probably other bits) assume to be called
  70          * from softirq context, not from syscall, like ipq_issue_verdict is
  71          * called.  TCP input path deadlocks with locks taken from timer
  72          * softirq, e.g.  We therefore emulate this by local_bh_disable() */
  73
  74         local_bh_disable();
  75         nf_reinject(entry->skb, entry->info, verdict);
  76         local_bh_enable();
  77
  78         kfree(entry);
  79 }
  80
  81 static inline void
  82 __ipq_enqueue_entry(struct ipq_queue_entry *entry)
  83 {
  84        list_add(&entry->list, &queue_list);
  85        queue_total++;
  86 }
  87
  88 /*
  89  * Find and return a queued entry matched by cmpfn, or return the last
  90  * entry if cmpfn is NULL.
  91  */
  92 static inline struct ipq_queue_entry *
  93 __ipq_find_entry(ipq_cmpfn cmpfn, unsigned long data)
  94 {
  95         struct list_head *p;
  96
  97         list_for_each_prev(p, &queue_list) {
  98                 struct ipq_queue_entry *entry = (struct ipq_queue_entry *)p;
  99
 100                 if (!cmpfn || cmpfn(entry, data))
 101                         return entry;
 102         }
 103         return NULL;
 104 }
 105
 106 static inline void
 107 __ipq_dequeue_entry(struct ipq_queue_entry *entry)
 108 {
 109         list_del(&entry->list);
 110         queue_total--;
 111 }
 112
 113 static inline struct ipq_queue_entry *
 114 __ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 115 {
 116         struct ipq_queue_entry *entry;
 117
 118         entry = __ipq_find_entry(cmpfn, data);
 119         if (entry == NULL)
 120                 return NULL;
 121
 122         __ipq_dequeue_entry(entry);
 123         return entry;
 124 }
 125
 126
 127 static inline void
 128 __ipq_flush(int verdict)
 129 {
 130         struct ipq_queue_entry *entry;
 131
 132         while ((entry = __ipq_find_dequeue_entry(NULL, 0)))
 133                 ipq_issue_verdict(entry, verdict);
 134 }
 135
 136 static inline int
 137 __ipq_set_mode(unsigned char mode, unsigned int range)
 138 {
 139         int status = 0;
 140
 141         switch(mode) {
 142         case IPQ_COPY_NONE:
 143         case IPQ_COPY_META:
 144                 copy_mode = mode;
 145                 copy_range = 0;
 146                 break;
 147
 148         case IPQ_COPY_PACKET:
 149                 copy_mode = mode;
 150                 copy_range = range;
 151                 if (copy_range > 0xFFFF)
 152                         copy_range = 0xFFFF;
 153                 break;
 154
 155         default:
 156                 status = -EINVAL;
 157
 158         }
 159         return status;
 160 }
 161
 162 static inline void
 163 __ipq_reset(void)
 164 {
 165         peer_pid = 0;
 166         net_disable_timestamp();
 167         __ipq_set_mode(IPQ_COPY_NONE, 0);
 168         __ipq_flush(NF_DROP);
 169 }
 170
 171 static struct ipq_queue_entry *
 172 ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 173 {
 174         struct ipq_queue_entry *entry;
 175
 176         write_lock_bh(&queue_lock);
 177         entry = __ipq_find_dequeue_entry(cmpfn, data);
 178         write_unlock_bh(&queue_lock);
 179         return entry;
 180 }
 181
 182 static void
 183 ipq_flush(int verdict)
 184 {
 185         write_lock_bh(&queue_lock);
 186         __ipq_flush(verdict);
 187         write_unlock_bh(&queue_lock);
 188 }
 189
 190 static struct sk_buff *
 191 ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
 192 {
 193         unsigned char *old_tail;
 194         size_t size = 0;
 195         size_t data_len = 0;
 196         struct sk_buff *skb;
 197         struct ipq_packet_msg *pmsg;
 198         struct nlmsghdr *nlh;
 199
 200         read_lock_bh(&queue_lock);
 201
 202         switch (copy_mode) {
 203         case IPQ_COPY_META:
 204         case IPQ_COPY_NONE:
 205                 size = NLMSG_SPACE(sizeof(*pmsg));
 206                 data_len = 0;
 207                 break;
 208
 209         case IPQ_COPY_PACKET:
 210                 if (entry->skb->ip_summed == CHECKSUM_HW &&
 211                     (*errp = skb_checksum_help(entry->skb,
 212                                                entry->info->outdev == NULL))) {
 213                         read_unlock_bh(&queue_lock);
 214                         return NULL;
 215                 }
 216                 if (copy_range == 0 || copy_range > entry->skb->len)
 217                         data_len = entry->skb->len;
 218                 else
 219                         data_len = copy_range;
 220
 221                 size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
 222                 break;
 223
 224         default:
 225                 *errp = -EINVAL;
 226                 read_unlock_bh(&queue_lock);
 227                 return NULL;
 228         }
 229
 230         read_unlock_bh(&queue_lock);
 231
 232         skb = alloc_skb(size, GFP_ATOMIC);
 233         if (!skb)
 234                 goto nlmsg_failure;
 235
 236         old_tail= skb->tail;
 237         nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
 238         pmsg = NLMSG_DATA(nlh);
 239         memset(pmsg, 0, sizeof(*pmsg));
 240
 241         pmsg->packet_id       = (unsigned long )entry;
 242         pmsg->data_len        = data_len;
 243         pmsg->timestamp_sec   = entry->skb->tstamp.off_sec;
 244         pmsg->timestamp_usec  = entry->skb->tstamp.off_usec;
 245         pmsg->mark            = entry->skb->nfmark;
 246         pmsg->hook            = entry->info->hook;
 247         pmsg->hw_protocol     = entry->skb->protocol;
 248
 249         if (entry->info->indev)
 250                 strcpy(pmsg->indev_name, entry->info->indev->name);
 251         else
 252                 pmsg->indev_name[0] = '\0';
 253
 254         if (entry->info->outdev)
 255                 strcpy(pmsg->outdev_name, entry->info->outdev->name);
 256         else
 257                 pmsg->outdev_name[0] = '\0';
 258
 259         if (entry->info->indev && entry->skb->dev) {
 260                 pmsg->hw_type = entry->skb->dev->type;
 261                 if (entry->skb->dev->hard_header_parse)
 262                         pmsg->hw_addrlen =
 263                                 entry->skb->dev->hard_header_parse(entry->skb,
 264                                                                    pmsg->hw_addr);
 265         }
 266
 267         if (data_len)
 268                 if (skb_copy_bits(entry->skb, 0, pmsg->payload, data_len))
 269                         BUG();
 270
 271         nlh->nlmsg_len = skb->tail - old_tail;
 272         return skb;
 273
 274 nlmsg_failure:
 275         if (skb)
 276                 kfree_skb(skb);
 277         *errp = -EINVAL;
 278         printk(KERN_ERR "ip_queue: error creating packet message\n");
 279         return NULL;
 280 }
 281
 282 static int
 283 ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info,
 284                    unsigned int queuenum, void *data)
 285 {
 286         int status = -EINVAL;
 287         struct sk_buff *nskb;
 288         struct ipq_queue_entry *entry;
 289
 290         if (copy_mode == IPQ_COPY_NONE)
 291                 return -EAGAIN;
 292
 293         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 294         if (entry == NULL) {
 295                 printk(KERN_ERR "ip_queue: OOM in ipq_enqueue_packet()\n");
 296                 return -ENOMEM;
 297         }
 298
 299         entry->info = info;
 300         entry->skb = skb;
 301
 302         nskb = ipq_build_packet_message(entry, &status);
 303         if (nskb == NULL)
 304                 goto err_out_free;
 305
 306         write_lock_bh(&queue_lock);
 307
 308         if (!peer_pid)
 309                 goto err_out_free_nskb;
 310
 311         if (queue_total >= queue_maxlen) {
 312                 queue_dropped++;
 313                 status = -ENOSPC;
 314                 if (net_ratelimit())
 315                           printk (KERN_WARNING "ip_queue: full at %d entries, "
 316                                   "dropping packets(s). Dropped: %d\n", queue_total,
 317                                   queue_dropped);
 318                 goto err_out_free_nskb;
 319         }
 320
 321         /* netlink_unicast will either free the nskb or attach it to a socket */
 322         status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
 323         if (status < 0) {
 324                 queue_user_dropped++;
 325                 goto err_out_unlock;
 326         }
 327
 328         __ipq_enqueue_entry(entry);
 329
 330         write_unlock_bh(&queue_lock);
 331         return status;
 332
 333 err_out_free_nskb:
 334         kfree_skb(nskb);
 335
 336 err_out_unlock:
 337         write_unlock_bh(&queue_lock);
 338
 339 err_out_free:
 340         kfree(entry);
 341         return status;
 342 }
 343
 344 static int
 345 ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
 346 {
 347         int diff;
 348         struct iphdr *user_iph = (struct iphdr *)v->payload;
 349
 350         if (v->data_len < sizeof(*user_iph))
 351                 return 0;
 352         diff = v->data_len - e->skb->len;
 353         if (diff < 0)
 354                 skb_trim(e->skb, v->data_len);
 355         else if (diff > 0) {
 356                 if (v->data_len > 0xFFFF)
 357                         return -EINVAL;
 358                 if (diff > skb_tailroom(e->skb)) {
 359                         struct sk_buff *newskb;
 360
 361                         newskb = skb_copy_expand(e->skb,
 362                                                  skb_headroom(e->skb),
 363                                                  diff,
 364                                                  GFP_ATOMIC);
 365                         if (newskb == NULL) {
 366                                 printk(KERN_WARNING "ip_queue: OOM "
 367                                       "in mangle, dropping packet\n");
 368                                 return -ENOMEM;
 369                         }
 370                         if (e->skb->sk)
 371                                 skb_set_owner_w(newskb, e->skb->sk);
 372                         kfree_skb(e->skb);
 373                         e->skb = newskb;
 374                 }
 375                 skb_put(e->skb, diff);
 376         }
 377         if (!skb_make_writable(&e->skb, v->data_len))
 378                 return -ENOMEM;
 379         memcpy(e->skb->data, v->payload, v->data_len);
 380         e->skb->ip_summed = CHECKSUM_NONE;
 381
 382         return 0;
 383 }
 384
 385 static inline int
 386 id_cmp(struct ipq_queue_entry *e, unsigned long id)
 387 {
 388         return (id == (unsigned long )e);
 389 }
 390
 391 static int
 392 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
 393 {
 394         struct ipq_queue_entry *entry;
 395
 396         if (vmsg->value > NF_MAX_VERDICT)
 397                 return -EINVAL;
 398
 399         entry = ipq_find_dequeue_entry(id_cmp, vmsg->id);
 400         if (entry == NULL)
 401                 return -ENOENT;
 402         else {
 403                 int verdict = vmsg->value;
 404
 405                 if (vmsg->data_len && vmsg->data_len == len)
 406                         if (ipq_mangle_ipv4(vmsg, entry) < 0)
 407                                 verdict = NF_DROP;
 408
 409                 ipq_issue_verdict(entry, verdict);
 410                 return 0;
 411         }
 412 }
 413
 414 static int
 415 ipq_set_mode(unsigned char mode, unsigned int range)
 416 {
 417         int status;
 418
 419         write_lock_bh(&queue_lock);
 420         status = __ipq_set_mode(mode, range);
 421         write_unlock_bh(&queue_lock);
 422         return status;
 423 }
 424
 425 static int
 426 ipq_receive_peer(struct ipq_peer_msg *pmsg,
 427                  unsigned char type, unsigned int len)
 428 {
 429         int status = 0;
 430
 431         if (len < sizeof(*pmsg))
 432                 return -EINVAL;
 433
 434         switch (type) {
 435         case IPQM_MODE:
 436                 status = ipq_set_mode(pmsg->msg.mode.value,
 437                                       pmsg->msg.mode.range);
 438                 break;
 439
 440         case IPQM_VERDICT:
 441                 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
 442                         status = -EINVAL;
 443                 else
 444                         status = ipq_set_verdict(&pmsg->msg.verdict,
 445                                                  len - sizeof(*pmsg));
 446                         break;
 447         default:
 448                 status = -EINVAL;
 449         }
 450         return status;
 451 }
 452
 453 static int
 454 dev_cmp(struct ipq_queue_entry *entry, unsigned long ifindex)
 455 {
 456         if (entry->info->indev)
 457                 if (entry->info->indev->ifindex == ifindex)
 458                         return 1;
 459
 460         if (entry->info->outdev)
 461                 if (entry->info->outdev->ifindex == ifindex)
 462                         return 1;
 463
 464         return 0;
 465 }
 466
 467 static void
 468 ipq_dev_drop(int ifindex)
 469 {
 470         struct ipq_queue_entry *entry;
 471
 472         while ((entry = ipq_find_dequeue_entry(dev_cmp, ifindex)) != NULL)
 473                 ipq_issue_verdict(entry, NF_DROP);
 474 }
 475
 476 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 477
 478 static inline void
 479 ipq_rcv_skb(struct sk_buff *skb)
 480 {
 481         int status, type, pid, flags, nlmsglen, skblen;
 482         struct nlmsghdr *nlh;
 483
 484         skblen = skb->len;
 485         if (skblen < sizeof(*nlh))
 486                 return;
 487
 488         nlh = (struct nlmsghdr *)skb->data;
 489         nlmsglen = nlh->nlmsg_len;
 490         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
 491                 return;
 492
 493         pid = nlh->nlmsg_pid;
 494         flags = nlh->nlmsg_flags;
 495
 496         if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
 497                 RCV_SKB_FAIL(-EINVAL);
 498
 499         if (flags & MSG_TRUNC)
 500                 RCV_SKB_FAIL(-ECOMM);
 501
 502         type = nlh->nlmsg_type;
 503         if (type < NLMSG_NOOP || type >= IPQM_MAX)
 504                 RCV_SKB_FAIL(-EINVAL);
 505
 506         if (type <= IPQM_BASE)
 507                 return;
 508
 509         if (security_netlink_recv(skb))
 510                 RCV_SKB_FAIL(-EPERM);
 511
 512         write_lock_bh(&queue_lock);
 513
 514         if (peer_pid) {
 515                 if (peer_pid != pid) {
 516                         write_unlock_bh(&queue_lock);
 517                         RCV_SKB_FAIL(-EBUSY);
 518                 }
 519         } else {
 520                 net_enable_timestamp();
 521                 peer_pid = pid;
 522         }
 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         struct sk_buff *skb;
 540         unsigned int qlen;
 541
 542         down(&ipqnl_sem);
 543
 544         for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
 545                 skb = skb_dequeue(&sk->sk_receive_queue);
 546                 ipq_rcv_skb(skb);
 547                 kfree_skb(skb);
 548         }
 549
 550         up(&ipqnl_sem);
 551 }
 552
 553 static int
 554 ipq_rcv_dev_event(struct notifier_block *this,
 555                   unsigned long event, void *ptr)
 556 {
 557         struct net_device *dev = ptr;
 558
 559         /* Drop any packets associated with the downed device */
 560         if (event == NETDEV_DOWN)
 561                 ipq_dev_drop(dev->ifindex);
 562         return NOTIFY_DONE;
 563 }
 564
 565 static struct notifier_block ipq_dev_notifier = {
 566         .notifier_call  = ipq_rcv_dev_event,
 567 };
 568
 569 static int
 570 ipq_rcv_nl_event(struct notifier_block *this,
 571                  unsigned long event, void *ptr)
 572 {
 573         struct netlink_notify *n = ptr;
 574
 575         if (event == NETLINK_URELEASE &&
 576             n->protocol == NETLINK_FIREWALL && n->pid) {
 577                 write_lock_bh(&queue_lock);
 578                 if (n->pid == peer_pid)
 579                         __ipq_reset();
 580                 write_unlock_bh(&queue_lock);
 581         }
 582         return NOTIFY_DONE;
 583 }
 584
 585 static struct notifier_block ipq_nl_notifier = {
 586         .notifier_call  = ipq_rcv_nl_event,
 587 };
 588
 589 static struct ctl_table_header *ipq_sysctl_header;
 590
 591 static ctl_table ipq_table[] = {
 592         {
 593                 .ctl_name       = NET_IPQ_QMAX,
 594                 .procname       = NET_IPQ_QMAX_NAME,
 595                 .data           = &queue_maxlen,
 596                 .maxlen         = sizeof(queue_maxlen),
 597                 .mode           = 0644,
 598                 .proc_handler   = proc_dointvec
 599         },
 600         { .ctl_name = 0 }
 601 };
 602
 603 static ctl_table ipq_dir_table[] = {
 604         {
 605                 .ctl_name       = NET_IPV4,
 606                 .procname       = "ipv4",
 607                 .mode           = 0555,
 608                 .child          = ipq_table
 609         },
 610         { .ctl_name = 0 }
 611 };
 612
 613 static ctl_table ipq_root_table[] = {
 614         {
 615                 .ctl_name       = CTL_NET,
 616                 .procname       = "net",
 617                 .mode           = 0555,
 618                 .child          = ipq_dir_table
 619         },
 620         { .ctl_name = 0 }
 621 };
 622
 623 #ifdef CONFIG_PROC_FS
 624 static int
 625 ipq_get_info(char *buffer, char **start, off_t offset, int length)
 626 {
 627         int len;
 628
 629         read_lock_bh(&queue_lock);
 630
 631         len = sprintf(buffer,
 632                       "Peer PID          : %d\n"
 633                       "Copy mode         : %hu\n"
 634                       "Copy range        : %u\n"
 635                       "Queue length      : %u\n"
 636                       "Queue max. length : %u\n"
 637                       "Queue dropped     : %u\n"
 638                       "Netlink dropped   : %u\n",
 639                       peer_pid,
 640                       copy_mode,
 641                       copy_range,
 642                       queue_total,
 643                       queue_maxlen,
 644                       queue_dropped,
 645                       queue_user_dropped);
 646
 647         read_unlock_bh(&queue_lock);
 648
 649         *start = buffer + offset;
 650         len -= offset;
 651         if (len > length)
 652                 len = length;
 653         else if (len < 0)
 654                 len = 0;
 655         return len;
 656 }
 657 #endif /* CONFIG_PROC_FS */
 658
 659 static struct nf_queue_handler nfqh = {
 660         .name   = "ip_queue",
 661         .outfn  = &ipq_enqueue_packet,
 662 };
 663
 664 static int
 665 init_or_cleanup(int init)
 666 {
 667         int status = -ENOMEM;
 668         struct proc_dir_entry *proc;
 669
 670         if (!init)
 671                 goto cleanup;
 672
 673         netlink_register_notifier(&ipq_nl_notifier);
 674         ipqnl = netlink_kernel_create(NETLINK_FIREWALL, 0, ipq_rcv_sk,
 675                                       THIS_MODULE);
 676         if (ipqnl == NULL) {
 677                 printk(KERN_ERR "ip_queue: failed to create netlink socket\n");
 678                 goto cleanup_netlink_notifier;
 679         }
 680
 681         proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
 682         if (proc)
 683                 proc->owner = THIS_MODULE;
 684         else {
 685                 printk(KERN_ERR "ip_queue: failed to create proc entry\n");
 686                 goto cleanup_ipqnl;
 687         }
 688
 689         register_netdevice_notifier(&ipq_dev_notifier);
 690         ipq_sysctl_header = register_sysctl_table(ipq_root_table, 0);
 691
 692         status = nf_register_queue_handler(PF_INET, &nfqh);
 693         if (status < 0) {
 694                 printk(KERN_ERR "ip_queue: failed to register queue handler\n");
 695                 goto cleanup_sysctl;
 696         }
 697         return status;
 698
 699 cleanup:
 700         nf_unregister_queue_handlers(&nfqh);
 701         synchronize_net();
 702         ipq_flush(NF_DROP);
 703
 704 cleanup_sysctl:
 705         unregister_sysctl_table(ipq_sysctl_header);
 706         unregister_netdevice_notifier(&ipq_dev_notifier);
 707         proc_net_remove(IPQ_PROC_FS_NAME);
 708
 709 cleanup_ipqnl:
 710         sock_release(ipqnl->sk_socket);
 711         down(&ipqnl_sem);
 712         up(&ipqnl_sem);
 713
 714 cleanup_netlink_notifier:
 715         netlink_unregister_notifier(&ipq_nl_notifier);
 716         return status;
 717 }
 718
 719 static int __init init(void)
 720 {
 721
 722         return init_or_cleanup(1);
 723 }
 724
 725 static void __exit fini(void)
 726 {
 727         init_or_cleanup(0);
 728 }
 729
 730 MODULE_DESCRIPTION("IPv4 packet queue handler");
 731 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
 732 MODULE_LICENSE("GPL");
 733
 734 module_init(init);
 735 module_exit(fini);