err.no Git - linux-2.6/blob - 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_rt_info {
  47         __u8 tos;
  48         __u32 daddr;
  49         __u32 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 unsigned int queue_dropped = 0;
  68 static unsigned int queue_user_dropped = 0;
  69 static struct sock *ipqnl;
  70 static LIST_HEAD(queue_list);
  71 static DECLARE_MUTEX(ipqnl_sem);
  72
  73 static void
  74 ipq_issue_verdict(struct ipq_queue_entry *entry, int verdict)
  75 {
  76         /* TCP input path (and probably other bits) assume to be called
  77          * from softirq context, not from syscall, like ipq_issue_verdict is
  78          * called.  TCP input path deadlocks with locks taken from timer
  79          * softirq, e.g.  We therefore emulate this by local_bh_disable() */
  80
  81         local_bh_disable();
  82         nf_reinject(entry->skb, entry->info, verdict);
  83         local_bh_enable();
  84
  85         kfree(entry);
  86 }
  87
  88 static inline void
  89 __ipq_enqueue_entry(struct ipq_queue_entry *entry)
  90 {
  91        list_add(&entry->list, &queue_list);
  92        queue_total++;
  93 }
  94
  95 /*
  96  * Find and return a queued entry matched by cmpfn, or return the last
  97  * entry if cmpfn is NULL.
  98  */
  99 static inline struct ipq_queue_entry *
 100 __ipq_find_entry(ipq_cmpfn cmpfn, unsigned long data)
 101 {
 102         struct list_head *p;
 103
 104         list_for_each_prev(p, &queue_list) {
 105                 struct ipq_queue_entry *entry = (struct ipq_queue_entry *)p;
 106
 107                 if (!cmpfn || cmpfn(entry, data))
 108                         return entry;
 109         }
 110         return NULL;
 111 }
 112
 113 static inline void
 114 __ipq_dequeue_entry(struct ipq_queue_entry *entry)
 115 {
 116         list_del(&entry->list);
 117         queue_total--;
 118 }
 119
 120 static inline struct ipq_queue_entry *
 121 __ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 122 {
 123         struct ipq_queue_entry *entry;
 124
 125         entry = __ipq_find_entry(cmpfn, data);
 126         if (entry == NULL)
 127                 return NULL;
 128
 129         __ipq_dequeue_entry(entry);
 130         return entry;
 131 }
 132
 133
 134 static inline void
 135 __ipq_flush(int verdict)
 136 {
 137         struct ipq_queue_entry *entry;
 138
 139         while ((entry = __ipq_find_dequeue_entry(NULL, 0)))
 140                 ipq_issue_verdict(entry, verdict);
 141 }
 142
 143 static inline int
 144 __ipq_set_mode(unsigned char mode, unsigned int range)
 145 {
 146         int status = 0;
 147
 148         switch(mode) {
 149         case IPQ_COPY_NONE:
 150         case IPQ_COPY_META:
 151                 copy_mode = mode;
 152                 copy_range = 0;
 153                 break;
 154
 155         case IPQ_COPY_PACKET:
 156                 copy_mode = mode;
 157                 copy_range = range;
 158                 if (copy_range > 0xFFFF)
 159                         copy_range = 0xFFFF;
 160                 break;
 161
 162         default:
 163                 status = -EINVAL;
 164
 165         }
 166         return status;
 167 }
 168
 169 static inline void
 170 __ipq_reset(void)
 171 {
 172         peer_pid = 0;
 173         net_disable_timestamp();
 174         __ipq_set_mode(IPQ_COPY_NONE, 0);
 175         __ipq_flush(NF_DROP);
 176 }
 177
 178 static struct ipq_queue_entry *
 179 ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 180 {
 181         struct ipq_queue_entry *entry;
 182
 183         write_lock_bh(&queue_lock);
 184         entry = __ipq_find_dequeue_entry(cmpfn, data);
 185         write_unlock_bh(&queue_lock);
 186         return entry;
 187 }
 188
 189 static void
 190 ipq_flush(int verdict)
 191 {
 192         write_lock_bh(&queue_lock);
 193         __ipq_flush(verdict);
 194         write_unlock_bh(&queue_lock);
 195 }
 196
 197 static struct sk_buff *
 198 ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
 199 {
 200         unsigned char *old_tail;
 201         size_t size = 0;
 202         size_t data_len = 0;
 203         struct sk_buff *skb;
 204         struct ipq_packet_msg *pmsg;
 205         struct nlmsghdr *nlh;
 206
 207         read_lock_bh(&queue_lock);
 208
 209         switch (copy_mode) {
 210         case IPQ_COPY_META:
 211         case IPQ_COPY_NONE:
 212                 size = NLMSG_SPACE(sizeof(*pmsg));
 213                 data_len = 0;
 214                 break;
 215
 216         case IPQ_COPY_PACKET:
 217                 if (entry->skb->ip_summed == CHECKSUM_HW &&
 218                     (*errp = skb_checksum_help(entry->skb,
 219                                                entry->info->outdev == NULL))) {
 220                         read_unlock_bh(&queue_lock);
 221                         return NULL;
 222                 }
 223                 if (copy_range == 0 || copy_range > entry->skb->len)
 224                         data_len = entry->skb->len;
 225                 else
 226                         data_len = copy_range;
 227
 228                 size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
 229                 break;
 230
 231         default:
 232                 *errp = -EINVAL;
 233                 read_unlock_bh(&queue_lock);
 234                 return NULL;
 235         }
 236
 237         read_unlock_bh(&queue_lock);
 238
 239         skb = alloc_skb(size, GFP_ATOMIC);
 240         if (!skb)
 241                 goto nlmsg_failure;
 242
 243         old_tail= skb->tail;
 244         nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
 245         pmsg = NLMSG_DATA(nlh);
 246         memset(pmsg, 0, sizeof(*pmsg));
 247
 248         pmsg->packet_id       = (unsigned long )entry;
 249         pmsg->data_len        = data_len;
 250         pmsg->timestamp_sec   = entry->skb->stamp.tv_sec;
 251         pmsg->timestamp_usec  = entry->skb->stamp.tv_usec;
 252         pmsg->mark            = entry->skb->nfmark;
 253         pmsg->hook            = entry->info->hook;
 254         pmsg->hw_protocol     = entry->skb->protocol;
 255
 256         if (entry->info->indev)
 257                 strcpy(pmsg->indev_name, entry->info->indev->name);
 258         else
 259                 pmsg->indev_name[0] = '\0';
 260
 261         if (entry->info->outdev)
 262                 strcpy(pmsg->outdev_name, entry->info->outdev->name);
 263         else
 264                 pmsg->outdev_name[0] = '\0';
 265
 266         if (entry->info->indev && entry->skb->dev) {
 267                 pmsg->hw_type = entry->skb->dev->type;
 268                 if (entry->skb->dev->hard_header_parse)
 269                         pmsg->hw_addrlen =
 270                                 entry->skb->dev->hard_header_parse(entry->skb,
 271                                                                    pmsg->hw_addr);
 272         }
 273
 274         if (data_len)
 275                 if (skb_copy_bits(entry->skb, 0, pmsg->payload, data_len))
 276                         BUG();
 277
 278         nlh->nlmsg_len = skb->tail - old_tail;
 279         return skb;
 280
 281 nlmsg_failure:
 282         if (skb)
 283                 kfree_skb(skb);
 284         *errp = -EINVAL;
 285         printk(KERN_ERR "ip_queue: error creating packet message\n");
 286         return NULL;
 287 }
 288
 289 static int
 290 ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, void *data)
 291 {
 292         int status = -EINVAL;
 293         struct sk_buff *nskb;
 294         struct ipq_queue_entry *entry;
 295
 296         if (copy_mode == IPQ_COPY_NONE)
 297                 return -EAGAIN;
 298
 299         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 300         if (entry == NULL) {
 301                 printk(KERN_ERR "ip_queue: OOM in ipq_enqueue_packet()\n");
 302                 return -ENOMEM;
 303         }
 304
 305         entry->info = info;
 306         entry->skb = skb;
 307
 308         if (entry->info->hook == NF_IP_LOCAL_OUT) {
 309                 struct iphdr *iph = skb->nh.iph;
 310
 311                 entry->rt_info.tos = iph->tos;
 312                 entry->rt_info.daddr = iph->daddr;
 313                 entry->rt_info.saddr = iph->saddr;
 314         }
 315
 316         nskb = ipq_build_packet_message(entry, &status);
 317         if (nskb == NULL)
 318                 goto err_out_free;
 319
 320         write_lock_bh(&queue_lock);
 321
 322         if (!peer_pid)
 323                 goto err_out_free_nskb;
 324
 325         if (queue_total >= queue_maxlen) {
 326                 queue_dropped++;
 327                 status = -ENOSPC;
 328                 if (net_ratelimit())
 329                           printk (KERN_WARNING "ip_queue: full at %d entries, "
 330                                   "dropping packets(s). Dropped: %d\n", queue_total,
 331                                   queue_dropped);
 332                 goto err_out_free_nskb;
 333         }
 334
 335         /* netlink_unicast will either free the nskb or attach it to a socket */
 336         status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
 337         if (status < 0) {
 338                 queue_user_dropped++;
 339                 goto err_out_unlock;
 340         }
 341
 342         __ipq_enqueue_entry(entry);
 343
 344         write_unlock_bh(&queue_lock);
 345         return status;
 346
 347 err_out_free_nskb:
 348         kfree_skb(nskb);
 349
 350 err_out_unlock:
 351         write_unlock_bh(&queue_lock);
 352
 353 err_out_free:
 354         kfree(entry);
 355         return status;
 356 }
 357
 358 static int
 359 ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
 360 {
 361         int diff;
 362         struct iphdr *user_iph = (struct iphdr *)v->payload;
 363
 364         if (v->data_len < sizeof(*user_iph))
 365                 return 0;
 366         diff = v->data_len - e->skb->len;
 367         if (diff < 0)
 368                 skb_trim(e->skb, v->data_len);
 369         else if (diff > 0) {
 370                 if (v->data_len > 0xFFFF)
 371                         return -EINVAL;
 372                 if (diff > skb_tailroom(e->skb)) {
 373                         struct sk_buff *newskb;
 374
 375                         newskb = skb_copy_expand(e->skb,
 376                                                  skb_headroom(e->skb),
 377                                                  diff,
 378                                                  GFP_ATOMIC);
 379                         if (newskb == NULL) {
 380                                 printk(KERN_WARNING "ip_queue: OOM "
 381                                       "in mangle, dropping packet\n");
 382                                 return -ENOMEM;
 383                         }
 384                         if (e->skb->sk)
 385                                 skb_set_owner_w(newskb, e->skb->sk);
 386                         kfree_skb(e->skb);
 387                         e->skb = newskb;
 388                 }
 389                 skb_put(e->skb, diff);
 390         }
 391         if (!skb_ip_make_writable(&e->skb, v->data_len))
 392                 return -ENOMEM;
 393         memcpy(e->skb->data, v->payload, v->data_len);
 394         e->skb->ip_summed = CHECKSUM_NONE;
 395         e->skb->nfcache |= NFC_ALTERED;
 396
 397         /*
 398          * Extra routing may needed on local out, as the QUEUE target never
 399          * returns control to the table.
 400          */
 401         if (e->info->hook == NF_IP_LOCAL_OUT) {
 402                 struct iphdr *iph = e->skb->nh.iph;
 403
 404                 if (!(iph->tos == e->rt_info.tos
 405                       && iph->daddr == e->rt_info.daddr
 406                       && iph->saddr == e->rt_info.saddr))
 407                         return ip_route_me_harder(&e->skb);
 408         }
 409         return 0;
 410 }
 411
 412 static inline int
 413 id_cmp(struct ipq_queue_entry *e, unsigned long id)
 414 {
 415         return (id == (unsigned long )e);
 416 }
 417
 418 static int
 419 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
 420 {
 421         struct ipq_queue_entry *entry;
 422
 423         if (vmsg->value > NF_MAX_VERDICT)
 424                 return -EINVAL;
 425
 426         entry = ipq_find_dequeue_entry(id_cmp, vmsg->id);
 427         if (entry == NULL)
 428                 return -ENOENT;
 429         else {
 430                 int verdict = vmsg->value;
 431
 432                 if (vmsg->data_len && vmsg->data_len == len)
 433                         if (ipq_mangle_ipv4(vmsg, entry) < 0)
 434                                 verdict = NF_DROP;
 435
 436                 ipq_issue_verdict(entry, verdict);
 437                 return 0;
 438         }
 439 }
 440
 441 static int
 442 ipq_set_mode(unsigned char mode, unsigned int range)
 443 {
 444         int status;
 445
 446         write_lock_bh(&queue_lock);
 447         status = __ipq_set_mode(mode, range);
 448         write_unlock_bh(&queue_lock);
 449         return status;
 450 }
 451
 452 static int
 453 ipq_receive_peer(struct ipq_peer_msg *pmsg,
 454                  unsigned char type, unsigned int len)
 455 {
 456         int status = 0;
 457
 458         if (len < sizeof(*pmsg))
 459                 return -EINVAL;
 460
 461         switch (type) {
 462         case IPQM_MODE:
 463                 status = ipq_set_mode(pmsg->msg.mode.value,
 464                                       pmsg->msg.mode.range);
 465                 break;
 466
 467         case IPQM_VERDICT:
 468                 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
 469                         status = -EINVAL;
 470                 else
 471                         status = ipq_set_verdict(&pmsg->msg.verdict,
 472                                                  len - sizeof(*pmsg));
 473                         break;
 474         default:
 475                 status = -EINVAL;
 476         }
 477         return status;
 478 }
 479
 480 static int
 481 dev_cmp(struct ipq_queue_entry *entry, unsigned long ifindex)
 482 {
 483         if (entry->info->indev)
 484                 if (entry->info->indev->ifindex == ifindex)
 485                         return 1;
 486
 487         if (entry->info->outdev)
 488                 if (entry->info->outdev->ifindex == ifindex)
 489                         return 1;
 490
 491         return 0;
 492 }
 493
 494 static void
 495 ipq_dev_drop(int ifindex)
 496 {
 497         struct ipq_queue_entry *entry;
 498
 499         while ((entry = ipq_find_dequeue_entry(dev_cmp, ifindex)) != NULL)
 500                 ipq_issue_verdict(entry, NF_DROP);
 501 }
 502
 503 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 504
 505 static inline void
 506 ipq_rcv_skb(struct sk_buff *skb)
 507 {
 508         int status, type, pid, flags, nlmsglen, skblen;
 509         struct nlmsghdr *nlh;
 510
 511         skblen = skb->len;
 512         if (skblen < sizeof(*nlh))
 513                 return;
 514
 515         nlh = (struct nlmsghdr *)skb->data;
 516         nlmsglen = nlh->nlmsg_len;
 517         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
 518                 return;
 519
 520         pid = nlh->nlmsg_pid;
 521         flags = nlh->nlmsg_flags;
 522
 523         if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
 524                 RCV_SKB_FAIL(-EINVAL);
 525
 526         if (flags & MSG_TRUNC)
 527                 RCV_SKB_FAIL(-ECOMM);
 528
 529         type = nlh->nlmsg_type;
 530         if (type < NLMSG_NOOP || type >= IPQM_MAX)
 531                 RCV_SKB_FAIL(-EINVAL);
 532
 533         if (type <= IPQM_BASE)
 534                 return;
 535
 536         if (security_netlink_recv(skb))
 537                 RCV_SKB_FAIL(-EPERM);
 538
 539         write_lock_bh(&queue_lock);
 540
 541         if (peer_pid) {
 542                 if (peer_pid != pid) {
 543                         write_unlock_bh(&queue_lock);
 544                         RCV_SKB_FAIL(-EBUSY);
 545                 }
 546         } else {
 547                 net_enable_timestamp();
 548                 peer_pid = pid;
 549         }
 550
 551         write_unlock_bh(&queue_lock);
 552
 553         status = ipq_receive_peer(NLMSG_DATA(nlh), type,
 554                                   skblen - NLMSG_LENGTH(0));
 555         if (status < 0)
 556                 RCV_SKB_FAIL(status);
 557
 558         if (flags & NLM_F_ACK)
 559                 netlink_ack(skb, nlh, 0);
 560         return;
 561 }
 562
 563 static void
 564 ipq_rcv_sk(struct sock *sk, int len)
 565 {
 566         struct sk_buff *skb;
 567         unsigned int qlen;
 568
 569         down(&ipqnl_sem);
 570
 571         for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
 572                 skb = skb_dequeue(&sk->sk_receive_queue);
 573                 ipq_rcv_skb(skb);
 574                 kfree_skb(skb);
 575         }
 576
 577         up(&ipqnl_sem);
 578 }
 579
 580 static int
 581 ipq_rcv_dev_event(struct notifier_block *this,
 582                   unsigned long event, void *ptr)
 583 {
 584         struct net_device *dev = ptr;
 585
 586         /* Drop any packets associated with the downed device */
 587         if (event == NETDEV_DOWN)
 588                 ipq_dev_drop(dev->ifindex);
 589         return NOTIFY_DONE;
 590 }
 591
 592 static struct notifier_block ipq_dev_notifier = {
 593         .notifier_call  = ipq_rcv_dev_event,
 594 };
 595
 596 static int
 597 ipq_rcv_nl_event(struct notifier_block *this,
 598                  unsigned long event, void *ptr)
 599 {
 600         struct netlink_notify *n = ptr;
 601
 602         if (event == NETLINK_URELEASE &&
 603             n->protocol == NETLINK_FIREWALL && n->pid) {
 604                 write_lock_bh(&queue_lock);
 605                 if (n->pid == peer_pid)
 606                         __ipq_reset();
 607                 write_unlock_bh(&queue_lock);
 608         }
 609         return NOTIFY_DONE;
 610 }
 611
 612 static struct notifier_block ipq_nl_notifier = {
 613         .notifier_call  = ipq_rcv_nl_event,
 614 };
 615
 616 static struct ctl_table_header *ipq_sysctl_header;
 617
 618 static ctl_table ipq_table[] = {
 619         {
 620                 .ctl_name       = NET_IPQ_QMAX,
 621                 .procname       = NET_IPQ_QMAX_NAME,
 622                 .data           = &queue_maxlen,
 623                 .maxlen         = sizeof(queue_maxlen),
 624                 .mode           = 0644,
 625                 .proc_handler   = proc_dointvec
 626         },
 627         { .ctl_name = 0 }
 628 };
 629
 630 static ctl_table ipq_dir_table[] = {
 631         {
 632                 .ctl_name       = NET_IPV4,
 633                 .procname       = "ipv4",
 634                 .mode           = 0555,
 635                 .child          = ipq_table
 636         },
 637         { .ctl_name = 0 }
 638 };
 639
 640 static ctl_table ipq_root_table[] = {
 641         {
 642                 .ctl_name       = CTL_NET,
 643                 .procname       = "net",
 644                 .mode           = 0555,
 645                 .child          = ipq_dir_table
 646         },
 647         { .ctl_name = 0 }
 648 };
 649
 650 #ifdef CONFIG_PROC_FS
 651 static int
 652 ipq_get_info(char *buffer, char **start, off_t offset, int length)
 653 {
 654         int len;
 655
 656         read_lock_bh(&queue_lock);
 657
 658         len = sprintf(buffer,
 659                       "Peer PID          : %d\n"
 660                       "Copy mode         : %hu\n"
 661                       "Copy range        : %u\n"
 662                       "Queue length      : %u\n"
 663                       "Queue max. length : %u\n"
 664                       "Queue dropped     : %u\n"
 665                       "Netlink dropped   : %u\n",
 666                       peer_pid,
 667                       copy_mode,
 668                       copy_range,
 669                       queue_total,
 670                       queue_maxlen,
 671                       queue_dropped,
 672                       queue_user_dropped);
 673
 674         read_unlock_bh(&queue_lock);
 675
 676         *start = buffer + offset;
 677         len -= offset;
 678         if (len > length)
 679                 len = length;
 680         else if (len < 0)
 681                 len = 0;
 682         return len;
 683 }
 684 #endif /* CONFIG_PROC_FS */
 685
 686 static int
 687 init_or_cleanup(int init)
 688 {
 689         int status = -ENOMEM;
 690         struct proc_dir_entry *proc;
 691
 692         if (!init)
 693                 goto cleanup;
 694
 695         netlink_register_notifier(&ipq_nl_notifier);
 696         ipqnl = netlink_kernel_create(NETLINK_FIREWALL, ipq_rcv_sk);
 697         if (ipqnl == NULL) {
 698                 printk(KERN_ERR "ip_queue: failed to create netlink socket\n");
 699                 goto cleanup_netlink_notifier;
 700         }
 701
 702         proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
 703         if (proc)
 704                 proc->owner = THIS_MODULE;
 705         else {
 706                 printk(KERN_ERR "ip_queue: failed to create proc entry\n");
 707                 goto cleanup_ipqnl;
 708         }
 709
 710         register_netdevice_notifier(&ipq_dev_notifier);
 711         ipq_sysctl_header = register_sysctl_table(ipq_root_table, 0);
 712
 713         status = nf_register_queue_handler(PF_INET, ipq_enqueue_packet, NULL);
 714         if (status < 0) {
 715                 printk(KERN_ERR "ip_queue: failed to register queue handler\n");
 716                 goto cleanup_sysctl;
 717         }
 718         return status;
 719
 720 cleanup:
 721         nf_unregister_queue_handler(PF_INET);
 722         synchronize_net();
 723         ipq_flush(NF_DROP);
 724
 725 cleanup_sysctl:
 726         unregister_sysctl_table(ipq_sysctl_header);
 727         unregister_netdevice_notifier(&ipq_dev_notifier);
 728         proc_net_remove(IPQ_PROC_FS_NAME);
 729
 730 cleanup_ipqnl:
 731         sock_release(ipqnl->sk_socket);
 732         down(&ipqnl_sem);
 733         up(&ipqnl_sem);
 734
 735 cleanup_netlink_notifier:
 736         netlink_unregister_notifier(&ipq_nl_notifier);
 737         return status;
 738 }
 739
 740 static int __init init(void)
 741 {
 742
 743         return init_or_cleanup(1);
 744 }
 745
 746 static void __exit fini(void)
 747 {
 748         init_or_cleanup(0);
 749 }
 750
 751 MODULE_DESCRIPTION("IPv4 packet queue handler");
 752 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
 753 MODULE_LICENSE("GPL");
 754
 755 module_init(init);
 756 module_exit(fini);