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 __read_mostly = IPQ_COPY_NONE;
  56 static unsigned int queue_maxlen __read_mostly = IPQ_QMAX_DEFAULT;
  57 static DEFINE_RWLOCK(queue_lock);
  58 static int peer_pid __read_mostly;
  59 static unsigned int copy_range __read_mostly;
  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 __read_mostly;
  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_PARTIAL ||
 212                      entry->skb->ip_summed == CHECKSUM_COMPLETE) &&
 213                     (*errp = skb_checksum_help(entry->skb))) {
 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->mark;
 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                 if (pskb_trim(e->skb, v->data_len))
 356                         return -ENOMEM;
 357         } else if (diff > 0) {
 358                 if (v->data_len > 0xFFFF)
 359                         return -EINVAL;
 360                 if (diff > skb_tailroom(e->skb)) {
 361                         struct sk_buff *newskb;
 362
 363                         newskb = skb_copy_expand(e->skb,
 364                                                  skb_headroom(e->skb),
 365                                                  diff,
 366                                                  GFP_ATOMIC);
 367                         if (newskb == NULL) {
 368                                 printk(KERN_WARNING "ip_queue: OOM "
 369                                       "in mangle, dropping packet\n");
 370                                 return -ENOMEM;
 371                         }
 372                         if (e->skb->sk)
 373                                 skb_set_owner_w(newskb, e->skb->sk);
 374                         kfree_skb(e->skb);
 375                         e->skb = newskb;
 376                 }
 377                 skb_put(e->skb, diff);
 378         }
 379         if (!skb_make_writable(&e->skb, v->data_len))
 380                 return -ENOMEM;
 381         memcpy(e->skb->data, v->payload, v->data_len);
 382         e->skb->ip_summed = CHECKSUM_NONE;
 383
 384         return 0;
 385 }
 386
 387 static inline int
 388 id_cmp(struct ipq_queue_entry *e, unsigned long id)
 389 {
 390         return (id == (unsigned long )e);
 391 }
 392
 393 static int
 394 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
 395 {
 396         struct ipq_queue_entry *entry;
 397
 398         if (vmsg->value > NF_MAX_VERDICT)
 399                 return -EINVAL;
 400
 401         entry = ipq_find_dequeue_entry(id_cmp, vmsg->id);
 402         if (entry == NULL)
 403                 return -ENOENT;
 404         else {
 405                 int verdict = vmsg->value;
 406
 407                 if (vmsg->data_len && vmsg->data_len == len)
 408                         if (ipq_mangle_ipv4(vmsg, entry) < 0)
 409                                 verdict = NF_DROP;
 410
 411                 ipq_issue_verdict(entry, verdict);
 412                 return 0;
 413         }
 414 }
 415
 416 static int
 417 ipq_set_mode(unsigned char mode, unsigned int range)
 418 {
 419         int status;
 420
 421         write_lock_bh(&queue_lock);
 422         status = __ipq_set_mode(mode, range);
 423         write_unlock_bh(&queue_lock);
 424         return status;
 425 }
 426
 427 static int
 428 ipq_receive_peer(struct ipq_peer_msg *pmsg,
 429                  unsigned char type, unsigned int len)
 430 {
 431         int status = 0;
 432
 433         if (len < sizeof(*pmsg))
 434                 return -EINVAL;
 435
 436         switch (type) {
 437         case IPQM_MODE:
 438                 status = ipq_set_mode(pmsg->msg.mode.value,
 439                                       pmsg->msg.mode.range);
 440                 break;
 441
 442         case IPQM_VERDICT:
 443                 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
 444                         status = -EINVAL;
 445                 else
 446                         status = ipq_set_verdict(&pmsg->msg.verdict,
 447                                                  len - sizeof(*pmsg));
 448                         break;
 449         default:
 450                 status = -EINVAL;
 451         }
 452         return status;
 453 }
 454
 455 static int
 456 dev_cmp(struct ipq_queue_entry *entry, unsigned long ifindex)
 457 {
 458         if (entry->info->indev)
 459                 if (entry->info->indev->ifindex == ifindex)
 460                         return 1;
 461         if (entry->info->outdev)
 462                 if (entry->info->outdev->ifindex == ifindex)
 463                         return 1;
 464 #ifdef CONFIG_BRIDGE_NETFILTER
 465         if (entry->skb->nf_bridge) {
 466                 if (entry->skb->nf_bridge->physindev &&
 467                     entry->skb->nf_bridge->physindev->ifindex == ifindex)
 468                         return 1;
 469                 if (entry->skb->nf_bridge->physoutdev &&
 470                     entry->skb->nf_bridge->physoutdev->ifindex == ifindex)
 471                         return 1;
 472         }
 473 #endif
 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, CAP_NET_ADMIN))
 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                                   nlmsglen - 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         mutex_lock(&ipqnl_mutex);
 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         mutex_unlock(&ipqnl_mutex);
 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 struct nf_queue_handler nfqh = {
 670         .name   = "ip_queue",
 671         .outfn  = &ipq_enqueue_packet,
 672 };
 673
 674 static int __init ip_queue_init(void)
 675 {
 676         int status = -ENOMEM;
 677         struct proc_dir_entry *proc;
 678
 679         netlink_register_notifier(&ipq_nl_notifier);
 680         ipqnl = netlink_kernel_create(NETLINK_FIREWALL, 0, ipq_rcv_sk,
 681                                       THIS_MODULE);
 682         if (ipqnl == NULL) {
 683                 printk(KERN_ERR "ip_queue: failed to create netlink socket\n");
 684                 goto cleanup_netlink_notifier;
 685         }
 686
 687         proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
 688         if (proc)
 689                 proc->owner = THIS_MODULE;
 690         else {
 691                 printk(KERN_ERR "ip_queue: failed to create proc entry\n");
 692                 goto cleanup_ipqnl;
 693         }
 694
 695         register_netdevice_notifier(&ipq_dev_notifier);
 696         ipq_sysctl_header = register_sysctl_table(ipq_root_table, 0);
 697
 698         status = nf_register_queue_handler(PF_INET, &nfqh);
 699         if (status < 0) {
 700                 printk(KERN_ERR "ip_queue: failed to register queue handler\n");
 701                 goto cleanup_sysctl;
 702         }
 703         return status;
 704
 705 cleanup_sysctl:
 706         unregister_sysctl_table(ipq_sysctl_header);
 707         unregister_netdevice_notifier(&ipq_dev_notifier);
 708         proc_net_remove(IPQ_PROC_FS_NAME);
 709
 710 cleanup_ipqnl:
 711         sock_release(ipqnl->sk_socket);
 712         mutex_lock(&ipqnl_mutex);
 713         mutex_unlock(&ipqnl_mutex);
 714
 715 cleanup_netlink_notifier:
 716         netlink_unregister_notifier(&ipq_nl_notifier);
 717         return status;
 718 }
 719
 720 static void __exit ip_queue_fini(void)
 721 {
 722         nf_unregister_queue_handlers(&nfqh);
 723         synchronize_net();
 724         ipq_flush(NF_DROP);
 725
 726         unregister_sysctl_table(ipq_sysctl_header);
 727         unregister_netdevice_notifier(&ipq_dev_notifier);
 728         proc_net_remove(IPQ_PROC_FS_NAME);
 729
 730         sock_release(ipqnl->sk_socket);
 731         mutex_lock(&ipqnl_mutex);
 732         mutex_unlock(&ipqnl_mutex);
 733
 734         netlink_unregister_notifier(&ipq_nl_notifier);
 735 }
 736
 737 MODULE_DESCRIPTION("IPv4 packet queue handler");
 738 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
 739 MODULE_LICENSE("GPL");
 740
 741 module_init(ip_queue_init);
 742 module_exit(ip_queue_fini);