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  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * 2000-03-27: Simplified code (thanks to Andi Kleen for clues).
  12  * 2000-05-20: Fixed notifier problems (following Miguel Freitas' report).
  13  * 2000-06-19: Fixed so nfmark is copied to metadata (reported by Sebastian
  14  *             Zander).
  15  * 2000-08-01: Added Nick Williams' MAC support.
  16  * 2002-06-25: Code cleanup.
  17  * 2005-01-10: Added /proc counter for dropped packets; fixed so
  18  *             packets aren't delivered to user space if they're going
  19  *             to be dropped.
  20  *
  21  */
  22 #include <linux/module.h>
  23 #include <linux/skbuff.h>
  24 #include <linux/init.h>
  25 #include <linux/ip.h>
  26 #include <linux/notifier.h>
  27 #include <linux/netdevice.h>
  28 #include <linux/netfilter.h>
  29 #include <linux/netfilter_ipv4/ip_queue.h>
  30 #include <linux/netfilter_ipv4/ip_tables.h>
  31 #include <linux/netlink.h>
  32 #include <linux/spinlock.h>
  33 #include <linux/sysctl.h>
  34 #include <linux/proc_fs.h>
  35 #include <linux/security.h>
  36 #include <net/sock.h>
  37 #include <net/route.h>
  38
  39 #define IPQ_QMAX_DEFAULT 1024
  40 #define IPQ_PROC_FS_NAME "ip_queue"
  41 #define NET_IPQ_QMAX 2088
  42 #define NET_IPQ_QMAX_NAME "ip_queue_maxlen"
  43
  44 struct ipq_rt_info {
  45         __u8 tos;
  46         __u32 daddr;
  47         __u32 saddr;
  48 };
  49
  50 struct ipq_queue_entry {
  51         struct list_head list;
  52         struct nf_info *info;
  53         struct sk_buff *skb;
  54         struct ipq_rt_info rt_info;
  55 };
  56
  57 typedef int (*ipq_cmpfn)(struct ipq_queue_entry *, unsigned long);
  58
  59 static unsigned char copy_mode = IPQ_COPY_NONE;
  60 static unsigned int queue_maxlen = IPQ_QMAX_DEFAULT;
  61 static DEFINE_RWLOCK(queue_lock);
  62 static int peer_pid;
  63 static unsigned int copy_range;
  64 static unsigned int queue_total;
  65 static unsigned int queue_dropped = 0;
  66 static unsigned int queue_user_dropped = 0;
  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 void
  79 __ipq_enqueue_entry(struct ipq_queue_entry *entry)
  80 {
  81        list_add(&entry->list, &queue_list);
  82        queue_total++;
  83 }
  84
  85 /*
  86  * Find and return a queued entry matched by cmpfn, or return the last
  87  * entry if cmpfn is NULL.
  88  */
  89 static inline struct ipq_queue_entry *
  90 __ipq_find_entry(ipq_cmpfn cmpfn, unsigned long data)
  91 {
  92         struct list_head *p;
  93
  94         list_for_each_prev(p, &queue_list) {
  95                 struct ipq_queue_entry *entry = (struct ipq_queue_entry *)p;
  96
  97                 if (!cmpfn || cmpfn(entry, data))
  98                         return entry;
  99         }
 100         return NULL;
 101 }
 102
 103 static inline void
 104 __ipq_dequeue_entry(struct ipq_queue_entry *entry)
 105 {
 106         list_del(&entry->list);
 107         queue_total--;
 108 }
 109
 110 static inline struct ipq_queue_entry *
 111 __ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 112 {
 113         struct ipq_queue_entry *entry;
 114
 115         entry = __ipq_find_entry(cmpfn, data);
 116         if (entry == NULL)
 117                 return NULL;
 118
 119         __ipq_dequeue_entry(entry);
 120         return entry;
 121 }
 122
 123
 124 static inline void
 125 __ipq_flush(int verdict)
 126 {
 127         struct ipq_queue_entry *entry;
 128
 129         while ((entry = __ipq_find_dequeue_entry(NULL, 0)))
 130                 ipq_issue_verdict(entry, verdict);
 131 }
 132
 133 static inline int
 134 __ipq_set_mode(unsigned char mode, unsigned int range)
 135 {
 136         int status = 0;
 137
 138         switch(mode) {
 139         case IPQ_COPY_NONE:
 140         case IPQ_COPY_META:
 141                 copy_mode = mode;
 142                 copy_range = 0;
 143                 break;
 144
 145         case IPQ_COPY_PACKET:
 146                 copy_mode = mode;
 147                 copy_range = range;
 148                 if (copy_range > 0xFFFF)
 149                         copy_range = 0xFFFF;
 150                 break;
 151
 152         default:
 153                 status = -EINVAL;
 154
 155         }
 156         return status;
 157 }
 158
 159 static inline void
 160 __ipq_reset(void)
 161 {
 162         peer_pid = 0;
 163         net_disable_timestamp();
 164         __ipq_set_mode(IPQ_COPY_NONE, 0);
 165         __ipq_flush(NF_DROP);
 166 }
 167
 168 static struct ipq_queue_entry *
 169 ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 170 {
 171         struct ipq_queue_entry *entry;
 172
 173         write_lock_bh(&queue_lock);
 174         entry = __ipq_find_dequeue_entry(cmpfn, data);
 175         write_unlock_bh(&queue_lock);
 176         return entry;
 177 }
 178
 179 static void
 180 ipq_flush(int verdict)
 181 {
 182         write_lock_bh(&queue_lock);
 183         __ipq_flush(verdict);
 184         write_unlock_bh(&queue_lock);
 185 }
 186
 187 static struct sk_buff *
 188 ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
 189 {
 190         unsigned char *old_tail;
 191         size_t size = 0;
 192         size_t data_len = 0;
 193         struct sk_buff *skb;
 194         struct ipq_packet_msg *pmsg;
 195         struct nlmsghdr *nlh;
 196
 197         read_lock_bh(&queue_lock);
 198
 199         switch (copy_mode) {
 200         case IPQ_COPY_META:
 201         case IPQ_COPY_NONE:
 202                 size = NLMSG_SPACE(sizeof(*pmsg));
 203                 data_len = 0;
 204                 break;
 205
 206         case IPQ_COPY_PACKET:
 207                 if (copy_range == 0 || copy_range > entry->skb->len)
 208                         data_len = entry->skb->len;
 209                 else
 210                         data_len = copy_range;
 211
 212                 size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
 213                 break;
 214
 215         default:
 216                 *errp = -EINVAL;
 217                 read_unlock_bh(&queue_lock);
 218                 return NULL;
 219         }
 220
 221         read_unlock_bh(&queue_lock);
 222
 223         skb = alloc_skb(size, GFP_ATOMIC);
 224         if (!skb)
 225                 goto nlmsg_failure;
 226
 227         old_tail= skb->tail;
 228         nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
 229         pmsg = NLMSG_DATA(nlh);
 230         memset(pmsg, 0, sizeof(*pmsg));
 231
 232         pmsg->packet_id       = (unsigned long )entry;
 233         pmsg->data_len        = data_len;
 234         pmsg->timestamp_sec   = entry->skb->stamp.tv_sec;
 235         pmsg->timestamp_usec  = entry->skb->stamp.tv_usec;
 236         pmsg->mark            = entry->skb->nfmark;
 237         pmsg->hook            = entry->info->hook;
 238         pmsg->hw_protocol     = entry->skb->protocol;
 239
 240         if (entry->info->indev)
 241                 strcpy(pmsg->indev_name, entry->info->indev->name);
 242         else
 243                 pmsg->indev_name[0] = '\0';
 244
 245         if (entry->info->outdev)
 246                 strcpy(pmsg->outdev_name, entry->info->outdev->name);
 247         else
 248                 pmsg->outdev_name[0] = '\0';
 249
 250         if (entry->info->indev && entry->skb->dev) {
 251                 pmsg->hw_type = entry->skb->dev->type;
 252                 if (entry->skb->dev->hard_header_parse)
 253                         pmsg->hw_addrlen =
 254                                 entry->skb->dev->hard_header_parse(entry->skb,
 255                                                                    pmsg->hw_addr);
 256         }
 257
 258         if (data_len)
 259                 if (skb_copy_bits(entry->skb, 0, pmsg->payload, data_len))
 260                         BUG();
 261
 262         nlh->nlmsg_len = skb->tail - old_tail;
 263         return skb;
 264
 265 nlmsg_failure:
 266         if (skb)
 267                 kfree_skb(skb);
 268         *errp = -EINVAL;
 269         printk(KERN_ERR "ip_queue: error creating packet message\n");
 270         return NULL;
 271 }
 272
 273 static int
 274 ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, void *data)
 275 {
 276         int status = -EINVAL;
 277         struct sk_buff *nskb;
 278         struct ipq_queue_entry *entry;
 279
 280         if (copy_mode == IPQ_COPY_NONE)
 281                 return -EAGAIN;
 282
 283         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 284         if (entry == NULL) {
 285                 printk(KERN_ERR "ip_queue: OOM in ipq_enqueue_packet()\n");
 286                 return -ENOMEM;
 287         }
 288
 289         entry->info = info;
 290         entry->skb = skb;
 291
 292         if (entry->info->hook == NF_IP_LOCAL_OUT) {
 293                 struct iphdr *iph = skb->nh.iph;
 294
 295                 entry->rt_info.tos = iph->tos;
 296                 entry->rt_info.daddr = iph->daddr;
 297                 entry->rt_info.saddr = iph->saddr;
 298         }
 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 "ip_queue: full at %d entries, "
 314                                   "dropping packets(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_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
 344 {
 345         int diff;
 346         struct iphdr *user_iph = (struct iphdr *)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 "ip_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_ip_make_writable(&e->skb, v->data_len))
 376                 return -ENOMEM;
 377         memcpy(e->skb->data, v->payload, v->data_len);
 378         e->skb->nfcache |= NFC_ALTERED;
 379
 380         /*
 381          * Extra routing may needed on local out, as the QUEUE target never
 382          * returns control to the table.
 383          */
 384         if (e->info->hook == NF_IP_LOCAL_OUT) {
 385                 struct iphdr *iph = e->skb->nh.iph;
 386
 387                 if (!(iph->tos == e->rt_info.tos
 388                       && iph->daddr == e->rt_info.daddr
 389                       && iph->saddr == e->rt_info.saddr))
 390                         return ip_route_me_harder(&e->skb);
 391         }
 392         return 0;
 393 }
 394
 395 static inline int
 396 id_cmp(struct ipq_queue_entry *e, unsigned long id)
 397 {
 398         return (id == (unsigned long )e);
 399 }
 400
 401 static int
 402 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
 403 {
 404         struct ipq_queue_entry *entry;
 405
 406         if (vmsg->value > NF_MAX_VERDICT)
 407                 return -EINVAL;
 408
 409         entry = ipq_find_dequeue_entry(id_cmp, vmsg->id);
 410         if (entry == NULL)
 411                 return -ENOENT;
 412         else {
 413                 int verdict = vmsg->value;
 414
 415                 if (vmsg->data_len && vmsg->data_len == len)
 416                         if (ipq_mangle_ipv4(vmsg, entry) < 0)
 417                                 verdict = NF_DROP;
 418
 419                 ipq_issue_verdict(entry, verdict);
 420                 return 0;
 421         }
 422 }
 423
 424 static int
 425 ipq_set_mode(unsigned char mode, unsigned int range)
 426 {
 427         int status;
 428
 429         write_lock_bh(&queue_lock);
 430         status = __ipq_set_mode(mode, range);
 431         write_unlock_bh(&queue_lock);
 432         return status;
 433 }
 434
 435 static int
 436 ipq_receive_peer(struct ipq_peer_msg *pmsg,
 437                  unsigned char type, unsigned int len)
 438 {
 439         int status = 0;
 440
 441         if (len < sizeof(*pmsg))
 442                 return -EINVAL;
 443
 444         switch (type) {
 445         case IPQM_MODE:
 446                 status = ipq_set_mode(pmsg->msg.mode.value,
 447                                       pmsg->msg.mode.range);
 448                 break;
 449
 450         case IPQM_VERDICT:
 451                 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
 452                         status = -EINVAL;
 453                 else
 454                         status = ipq_set_verdict(&pmsg->msg.verdict,
 455                                                  len - sizeof(*pmsg));
 456                         break;
 457         default:
 458                 status = -EINVAL;
 459         }
 460         return status;
 461 }
 462
 463 static int
 464 dev_cmp(struct ipq_queue_entry *entry, unsigned long ifindex)
 465 {
 466         if (entry->info->indev)
 467                 if (entry->info->indev->ifindex == ifindex)
 468                         return 1;
 469
 470         if (entry->info->outdev)
 471                 if (entry->info->outdev->ifindex == ifindex)
 472                         return 1;
 473
 474         return 0;
 475 }
 476
 477 static void
 478 ipq_dev_drop(int ifindex)
 479 {
 480         struct ipq_queue_entry *entry;
 481
 482         while ((entry = ipq_find_dequeue_entry(dev_cmp, ifindex)) != NULL)
 483                 ipq_issue_verdict(entry, NF_DROP);
 484 }
 485
 486 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 487
 488 static inline void
 489 ipq_rcv_skb(struct sk_buff *skb)
 490 {
 491         int status, type, pid, flags, nlmsglen, skblen;
 492         struct nlmsghdr *nlh;
 493
 494         skblen = skb->len;
 495         if (skblen < sizeof(*nlh))
 496                 return;
 497
 498         nlh = (struct nlmsghdr *)skb->data;
 499         nlmsglen = nlh->nlmsg_len;
 500         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
 501                 return;
 502
 503         pid = nlh->nlmsg_pid;
 504         flags = nlh->nlmsg_flags;
 505
 506         if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
 507                 RCV_SKB_FAIL(-EINVAL);
 508
 509         if (flags & MSG_TRUNC)
 510                 RCV_SKB_FAIL(-ECOMM);
 511
 512         type = nlh->nlmsg_type;
 513         if (type < NLMSG_NOOP || type >= IPQM_MAX)
 514                 RCV_SKB_FAIL(-EINVAL);
 515
 516         if (type <= IPQM_BASE)
 517                 return;
 518
 519         if (security_netlink_recv(skb))
 520                 RCV_SKB_FAIL(-EPERM);
 521
 522         write_lock_bh(&queue_lock);
 523
 524         if (peer_pid) {
 525                 if (peer_pid != pid) {
 526                         write_unlock_bh(&queue_lock);
 527                         RCV_SKB_FAIL(-EBUSY);
 528                 }
 529         } else {
 530                 net_enable_timestamp();
 531                 peer_pid = pid;
 532         }
 533
 534         write_unlock_bh(&queue_lock);
 535
 536         status = ipq_receive_peer(NLMSG_DATA(nlh), type,
 537                                   skblen - NLMSG_LENGTH(0));
 538         if (status < 0)
 539                 RCV_SKB_FAIL(status);
 540
 541         if (flags & NLM_F_ACK)
 542                 netlink_ack(skb, nlh, 0);
 543         return;
 544 }
 545
 546 static void
 547 ipq_rcv_sk(struct sock *sk, int len)
 548 {
 549         struct sk_buff *skb;
 550         unsigned int qlen;
 551
 552         down(&ipqnl_sem);
 553
 554         for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
 555                 skb = skb_dequeue(&sk->sk_receive_queue);
 556                 ipq_rcv_skb(skb);
 557                 kfree_skb(skb);
 558         }
 559
 560         up(&ipqnl_sem);
 561 }
 562
 563 static int
 564 ipq_rcv_dev_event(struct notifier_block *this,
 565                   unsigned long event, void *ptr)
 566 {
 567         struct net_device *dev = ptr;
 568
 569         /* Drop any packets associated with the downed device */
 570         if (event == NETDEV_DOWN)
 571                 ipq_dev_drop(dev->ifindex);
 572         return NOTIFY_DONE;
 573 }
 574
 575 static struct notifier_block ipq_dev_notifier = {
 576         .notifier_call  = ipq_rcv_dev_event,
 577 };
 578
 579 static int
 580 ipq_rcv_nl_event(struct notifier_block *this,
 581                  unsigned long event, void *ptr)
 582 {
 583         struct netlink_notify *n = ptr;
 584
 585         if (event == NETLINK_URELEASE &&
 586             n->protocol == NETLINK_FIREWALL && n->pid) {
 587                 write_lock_bh(&queue_lock);
 588                 if (n->pid == peer_pid)
 589                         __ipq_reset();
 590                 write_unlock_bh(&queue_lock);
 591         }
 592         return NOTIFY_DONE;
 593 }
 594
 595 static struct notifier_block ipq_nl_notifier = {
 596         .notifier_call  = ipq_rcv_nl_event,
 597 };
 598
 599 static struct ctl_table_header *ipq_sysctl_header;
 600
 601 static ctl_table ipq_table[] = {
 602         {
 603                 .ctl_name       = NET_IPQ_QMAX,
 604                 .procname       = NET_IPQ_QMAX_NAME,
 605                 .data           = &queue_maxlen,
 606                 .maxlen         = sizeof(queue_maxlen),
 607                 .mode           = 0644,
 608                 .proc_handler   = proc_dointvec
 609         },
 610         { .ctl_name = 0 }
 611 };
 612
 613 static ctl_table ipq_dir_table[] = {
 614         {
 615                 .ctl_name       = NET_IPV4,
 616                 .procname       = "ipv4",
 617                 .mode           = 0555,
 618                 .child          = ipq_table
 619         },
 620         { .ctl_name = 0 }
 621 };
 622
 623 static ctl_table ipq_root_table[] = {
 624         {
 625                 .ctl_name       = CTL_NET,
 626                 .procname       = "net",
 627                 .mode           = 0555,
 628                 .child          = ipq_dir_table
 629         },
 630         { .ctl_name = 0 }
 631 };
 632
 633 #ifdef CONFIG_PROC_FS
 634 static int
 635 ipq_get_info(char *buffer, char **start, off_t offset, int length)
 636 {
 637         int len;
 638
 639         read_lock_bh(&queue_lock);
 640
 641         len = sprintf(buffer,
 642                       "Peer PID          : %d\n"
 643                       "Copy mode         : %hu\n"
 644                       "Copy range        : %u\n"
 645                       "Queue length      : %u\n"
 646                       "Queue max. length : %u\n"
 647                       "Queue dropped     : %u\n"
 648                       "Netlink dropped   : %u\n",
 649                       peer_pid,
 650                       copy_mode,
 651                       copy_range,
 652                       queue_total,
 653                       queue_maxlen,
 654                       queue_dropped,
 655                       queue_user_dropped);
 656
 657         read_unlock_bh(&queue_lock);
 658
 659         *start = buffer + offset;
 660         len -= offset;
 661         if (len > length)
 662                 len = length;
 663         else if (len < 0)
 664                 len = 0;
 665         return len;
 666 }
 667 #endif /* CONFIG_PROC_FS */
 668
 669 static int
 670 init_or_cleanup(int init)
 671 {
 672         int status = -ENOMEM;
 673         struct proc_dir_entry *proc;
 674
 675         if (!init)
 676                 goto cleanup;
 677
 678         netlink_register_notifier(&ipq_nl_notifier);
 679         ipqnl = netlink_kernel_create(NETLINK_FIREWALL, ipq_rcv_sk);
 680         if (ipqnl == NULL) {
 681                 printk(KERN_ERR "ip_queue: failed to create netlink socket\n");
 682                 goto cleanup_netlink_notifier;
 683         }
 684
 685         proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
 686         if (proc)
 687                 proc->owner = THIS_MODULE;
 688         else {
 689                 printk(KERN_ERR "ip_queue: failed to create proc entry\n");
 690                 goto cleanup_ipqnl;
 691         }
 692
 693         register_netdevice_notifier(&ipq_dev_notifier);
 694         ipq_sysctl_header = register_sysctl_table(ipq_root_table, 0);
 695
 696         status = nf_register_queue_handler(PF_INET, ipq_enqueue_packet, NULL);
 697         if (status < 0) {
 698                 printk(KERN_ERR "ip_queue: failed to register queue handler\n");
 699                 goto cleanup_sysctl;
 700         }
 701         return status;
 702
 703 cleanup:
 704         nf_unregister_queue_handler(PF_INET);
 705         synchronize_net();
 706         ipq_flush(NF_DROP);
 707
 708 cleanup_sysctl:
 709         unregister_sysctl_table(ipq_sysctl_header);
 710         unregister_netdevice_notifier(&ipq_dev_notifier);
 711         proc_net_remove(IPQ_PROC_FS_NAME);
 712
 713 cleanup_ipqnl:
 714         sock_release(ipqnl->sk_socket);
 715         down(&ipqnl_sem);
 716         up(&ipqnl_sem);
 717
 718 cleanup_netlink_notifier:
 719         netlink_unregister_notifier(&ipq_nl_notifier);
 720         return status;
 721 }
 722
 723 static int __init init(void)
 724 {
 725
 726         return init_or_cleanup(1);
 727 }
 728
 729 static void __exit fini(void)
 730 {
 731         init_or_cleanup(0);
 732 }
 733
 734 MODULE_DESCRIPTION("IPv4 packet queue handler");
 735 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
 736 MODULE_LICENSE("GPL");
 737
 738 module_init(init);
 739 module_exit(fini);