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         sk_buff_data_t 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         struct timeval tv;
 201
 202         read_lock_bh(&queue_lock);
 203
 204         switch (copy_mode) {
 205         case IPQ_COPY_META:
 206         case IPQ_COPY_NONE:
 207                 size = NLMSG_SPACE(sizeof(*pmsg));
 208                 data_len = 0;
 209                 break;
 210
 211         case IPQ_COPY_PACKET:
 212                 if ((entry->skb->ip_summed == CHECKSUM_PARTIAL ||
 213                      entry->skb->ip_summed == CHECKSUM_COMPLETE) &&
 214                     (*errp = skb_checksum_help(entry->skb))) {
 215                         read_unlock_bh(&queue_lock);
 216                         return NULL;
 217                 }
 218                 if (copy_range == 0 || copy_range > entry->skb->len)
 219                         data_len = entry->skb->len;
 220                 else
 221                         data_len = copy_range;
 222
 223                 size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
 224                 break;
 225
 226         default:
 227                 *errp = -EINVAL;
 228                 read_unlock_bh(&queue_lock);
 229                 return NULL;
 230         }
 231
 232         read_unlock_bh(&queue_lock);
 233
 234         skb = alloc_skb(size, GFP_ATOMIC);
 235         if (!skb)
 236                 goto nlmsg_failure;
 237
 238         old_tail = skb->tail;
 239         nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
 240         pmsg = NLMSG_DATA(nlh);
 241         memset(pmsg, 0, sizeof(*pmsg));
 242
 243         pmsg->packet_id       = (unsigned long )entry;
 244         pmsg->data_len        = data_len;
 245         tv = ktime_to_timeval(entry->skb->tstamp);
 246         pmsg->timestamp_sec   = tv.tv_sec;
 247         pmsg->timestamp_usec  = tv.tv_usec;
 248         pmsg->mark            = entry->skb->mark;
 249         pmsg->hook            = entry->info->hook;
 250         pmsg->hw_protocol     = entry->skb->protocol;
 251
 252         if (entry->info->indev)
 253                 strcpy(pmsg->indev_name, entry->info->indev->name);
 254         else
 255                 pmsg->indev_name[0] = '\0';
 256
 257         if (entry->info->outdev)
 258                 strcpy(pmsg->outdev_name, entry->info->outdev->name);
 259         else
 260                 pmsg->outdev_name[0] = '\0';
 261
 262         if (entry->info->indev && entry->skb->dev) {
 263                 pmsg->hw_type = entry->skb->dev->type;
 264                 if (entry->skb->dev->hard_header_parse)
 265                         pmsg->hw_addrlen =
 266                                 entry->skb->dev->hard_header_parse(entry->skb,
 267                                                                    pmsg->hw_addr);
 268         }
 269
 270         if (data_len)
 271                 if (skb_copy_bits(entry->skb, 0, pmsg->payload, data_len))
 272                         BUG();
 273
 274         nlh->nlmsg_len = skb->tail - old_tail;
 275         return skb;
 276
 277 nlmsg_failure:
 278         if (skb)
 279                 kfree_skb(skb);
 280         *errp = -EINVAL;
 281         printk(KERN_ERR "ip_queue: error creating packet message\n");
 282         return NULL;
 283 }
 284
 285 static int
 286 ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info,
 287                    unsigned int queuenum, void *data)
 288 {
 289         int status = -EINVAL;
 290         struct sk_buff *nskb;
 291         struct ipq_queue_entry *entry;
 292
 293         if (copy_mode == IPQ_COPY_NONE)
 294                 return -EAGAIN;
 295
 296         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 297         if (entry == NULL) {
 298                 printk(KERN_ERR "ip_queue: OOM in ipq_enqueue_packet()\n");
 299                 return -ENOMEM;
 300         }
 301
 302         entry->info = info;
 303         entry->skb = skb;
 304
 305         nskb = ipq_build_packet_message(entry, &status);
 306         if (nskb == NULL)
 307                 goto err_out_free;
 308
 309         write_lock_bh(&queue_lock);
 310
 311         if (!peer_pid)
 312                 goto err_out_free_nskb;
 313
 314         if (queue_total >= queue_maxlen) {
 315                 queue_dropped++;
 316                 status = -ENOSPC;
 317                 if (net_ratelimit())
 318                           printk (KERN_WARNING "ip_queue: full at %d entries, "
 319                                   "dropping packets(s). Dropped: %d\n", queue_total,
 320                                   queue_dropped);
 321                 goto err_out_free_nskb;
 322         }
 323
 324         /* netlink_unicast will either free the nskb or attach it to a socket */
 325         status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
 326         if (status < 0) {
 327                 queue_user_dropped++;
 328                 goto err_out_unlock;
 329         }
 330
 331         __ipq_enqueue_entry(entry);
 332
 333         write_unlock_bh(&queue_lock);
 334         return status;
 335
 336 err_out_free_nskb:
 337         kfree_skb(nskb);
 338
 339 err_out_unlock:
 340         write_unlock_bh(&queue_lock);
 341
 342 err_out_free:
 343         kfree(entry);
 344         return status;
 345 }
 346
 347 static int
 348 ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
 349 {
 350         int diff;
 351         struct iphdr *user_iph = (struct iphdr *)v->payload;
 352
 353         if (v->data_len < sizeof(*user_iph))
 354                 return 0;
 355         diff = v->data_len - e->skb->len;
 356         if (diff < 0) {
 357                 if (pskb_trim(e->skb, v->data_len))
 358                         return -ENOMEM;
 359         } else if (diff > 0) {
 360                 if (v->data_len > 0xFFFF)
 361                         return -EINVAL;
 362                 if (diff > skb_tailroom(e->skb)) {
 363                         struct sk_buff *newskb;
 364
 365                         newskb = skb_copy_expand(e->skb,
 366                                                  skb_headroom(e->skb),
 367                                                  diff,
 368                                                  GFP_ATOMIC);
 369                         if (newskb == NULL) {
 370                                 printk(KERN_WARNING "ip_queue: OOM "
 371                                       "in mangle, dropping packet\n");
 372                                 return -ENOMEM;
 373                         }
 374                         if (e->skb->sk)
 375                                 skb_set_owner_w(newskb, e->skb->sk);
 376                         kfree_skb(e->skb);
 377                         e->skb = newskb;
 378                 }
 379                 skb_put(e->skb, diff);
 380         }
 381         if (!skb_make_writable(&e->skb, v->data_len))
 382                 return -ENOMEM;
 383         memcpy(e->skb->data, v->payload, v->data_len);
 384         e->skb->ip_summed = CHECKSUM_NONE;
 385
 386         return 0;
 387 }
 388
 389 static inline int
 390 id_cmp(struct ipq_queue_entry *e, unsigned long id)
 391 {
 392         return (id == (unsigned long )e);
 393 }
 394
 395 static int
 396 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
 397 {
 398         struct ipq_queue_entry *entry;
 399
 400         if (vmsg->value > NF_MAX_VERDICT)
 401                 return -EINVAL;
 402
 403         entry = ipq_find_dequeue_entry(id_cmp, vmsg->id);
 404         if (entry == NULL)
 405                 return -ENOENT;
 406         else {
 407                 int verdict = vmsg->value;
 408
 409                 if (vmsg->data_len && vmsg->data_len == len)
 410                         if (ipq_mangle_ipv4(vmsg, entry) < 0)
 411                                 verdict = NF_DROP;
 412
 413                 ipq_issue_verdict(entry, verdict);
 414                 return 0;
 415         }
 416 }
 417
 418 static int
 419 ipq_set_mode(unsigned char mode, unsigned int range)
 420 {
 421         int status;
 422
 423         write_lock_bh(&queue_lock);
 424         status = __ipq_set_mode(mode, range);
 425         write_unlock_bh(&queue_lock);
 426         return status;
 427 }
 428
 429 static int
 430 ipq_receive_peer(struct ipq_peer_msg *pmsg,
 431                  unsigned char type, unsigned int len)
 432 {
 433         int status = 0;
 434
 435         if (len < sizeof(*pmsg))
 436                 return -EINVAL;
 437
 438         switch (type) {
 439         case IPQM_MODE:
 440                 status = ipq_set_mode(pmsg->msg.mode.value,
 441                                       pmsg->msg.mode.range);
 442                 break;
 443
 444         case IPQM_VERDICT:
 445                 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
 446                         status = -EINVAL;
 447                 else
 448                         status = ipq_set_verdict(&pmsg->msg.verdict,
 449                                                  len - sizeof(*pmsg));
 450                         break;
 451         default:
 452                 status = -EINVAL;
 453         }
 454         return status;
 455 }
 456
 457 static int
 458 dev_cmp(struct ipq_queue_entry *entry, unsigned long ifindex)
 459 {
 460         if (entry->info->indev)
 461                 if (entry->info->indev->ifindex == ifindex)
 462                         return 1;
 463         if (entry->info->outdev)
 464                 if (entry->info->outdev->ifindex == ifindex)
 465                         return 1;
 466 #ifdef CONFIG_BRIDGE_NETFILTER
 467         if (entry->skb->nf_bridge) {
 468                 if (entry->skb->nf_bridge->physindev &&
 469                     entry->skb->nf_bridge->physindev->ifindex == ifindex)
 470                         return 1;
 471                 if (entry->skb->nf_bridge->physoutdev &&
 472                     entry->skb->nf_bridge->physoutdev->ifindex == ifindex)
 473                         return 1;
 474         }
 475 #endif
 476         return 0;
 477 }
 478
 479 static void
 480 ipq_dev_drop(int ifindex)
 481 {
 482         struct ipq_queue_entry *entry;
 483
 484         while ((entry = ipq_find_dequeue_entry(dev_cmp, ifindex)) != NULL)
 485                 ipq_issue_verdict(entry, NF_DROP);
 486 }
 487
 488 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 489
 490 static inline void
 491 ipq_rcv_skb(struct sk_buff *skb)
 492 {
 493         int status, type, pid, flags, nlmsglen, skblen;
 494         struct nlmsghdr *nlh;
 495
 496         skblen = skb->len;
 497         if (skblen < sizeof(*nlh))
 498                 return;
 499
 500         nlh = nlmsg_hdr(skb);
 501         nlmsglen = nlh->nlmsg_len;
 502         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
 503                 return;
 504
 505         pid = nlh->nlmsg_pid;
 506         flags = nlh->nlmsg_flags;
 507
 508         if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
 509                 RCV_SKB_FAIL(-EINVAL);
 510
 511         if (flags & MSG_TRUNC)
 512                 RCV_SKB_FAIL(-ECOMM);
 513
 514         type = nlh->nlmsg_type;
 515         if (type < NLMSG_NOOP || type >= IPQM_MAX)
 516                 RCV_SKB_FAIL(-EINVAL);
 517
 518         if (type <= IPQM_BASE)
 519                 return;
 520
 521         if (security_netlink_recv(skb, CAP_NET_ADMIN))
 522                 RCV_SKB_FAIL(-EPERM);
 523
 524         write_lock_bh(&queue_lock);
 525
 526         if (peer_pid) {
 527                 if (peer_pid != pid) {
 528                         write_unlock_bh(&queue_lock);
 529                         RCV_SKB_FAIL(-EBUSY);
 530                 }
 531         } else {
 532                 net_enable_timestamp();
 533                 peer_pid = pid;
 534         }
 535
 536         write_unlock_bh(&queue_lock);
 537
 538         status = ipq_receive_peer(NLMSG_DATA(nlh), type,
 539                                   nlmsglen - NLMSG_LENGTH(0));
 540         if (status < 0)
 541                 RCV_SKB_FAIL(status);
 542
 543         if (flags & NLM_F_ACK)
 544                 netlink_ack(skb, nlh, 0);
 545         return;
 546 }
 547
 548 static void
 549 ipq_rcv_sk(struct sock *sk, int len)
 550 {
 551         struct sk_buff *skb;
 552         unsigned int qlen;
 553
 554         mutex_lock(&ipqnl_mutex);
 555
 556         for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
 557                 skb = skb_dequeue(&sk->sk_receive_queue);
 558                 ipq_rcv_skb(skb);
 559                 kfree_skb(skb);
 560         }
 561
 562         mutex_unlock(&ipqnl_mutex);
 563 }
 564
 565 static int
 566 ipq_rcv_dev_event(struct notifier_block *this,
 567                   unsigned long event, void *ptr)
 568 {
 569         struct net_device *dev = ptr;
 570
 571         /* Drop any packets associated with the downed device */
 572         if (event == NETDEV_DOWN)
 573                 ipq_dev_drop(dev->ifindex);
 574         return NOTIFY_DONE;
 575 }
 576
 577 static struct notifier_block ipq_dev_notifier = {
 578         .notifier_call  = ipq_rcv_dev_event,
 579 };
 580
 581 static int
 582 ipq_rcv_nl_event(struct notifier_block *this,
 583                  unsigned long event, void *ptr)
 584 {
 585         struct netlink_notify *n = ptr;
 586
 587         if (event == NETLINK_URELEASE &&
 588             n->protocol == NETLINK_FIREWALL && n->pid) {
 589                 write_lock_bh(&queue_lock);
 590                 if (n->pid == peer_pid)
 591                         __ipq_reset();
 592                 write_unlock_bh(&queue_lock);
 593         }
 594         return NOTIFY_DONE;
 595 }
 596
 597 static struct notifier_block ipq_nl_notifier = {
 598         .notifier_call  = ipq_rcv_nl_event,
 599 };
 600
 601 static struct ctl_table_header *ipq_sysctl_header;
 602
 603 static ctl_table ipq_table[] = {
 604         {
 605                 .ctl_name       = NET_IPQ_QMAX,
 606                 .procname       = NET_IPQ_QMAX_NAME,
 607                 .data           = &queue_maxlen,
 608                 .maxlen         = sizeof(queue_maxlen),
 609                 .mode           = 0644,
 610                 .proc_handler   = proc_dointvec
 611         },
 612         { .ctl_name = 0 }
 613 };
 614
 615 static ctl_table ipq_dir_table[] = {
 616         {
 617                 .ctl_name       = NET_IPV4,
 618                 .procname       = "ipv4",
 619                 .mode           = 0555,
 620                 .child          = ipq_table
 621         },
 622         { .ctl_name = 0 }
 623 };
 624
 625 static ctl_table ipq_root_table[] = {
 626         {
 627                 .ctl_name       = CTL_NET,
 628                 .procname       = "net",
 629                 .mode           = 0555,
 630                 .child          = ipq_dir_table
 631         },
 632         { .ctl_name = 0 }
 633 };
 634
 635 #ifdef CONFIG_PROC_FS
 636 static int
 637 ipq_get_info(char *buffer, char **start, off_t offset, int length)
 638 {
 639         int len;
 640
 641         read_lock_bh(&queue_lock);
 642
 643         len = sprintf(buffer,
 644                       "Peer PID          : %d\n"
 645                       "Copy mode         : %hu\n"
 646                       "Copy range        : %u\n"
 647                       "Queue length      : %u\n"
 648                       "Queue max. length : %u\n"
 649                       "Queue dropped     : %u\n"
 650                       "Netlink dropped   : %u\n",
 651                       peer_pid,
 652                       copy_mode,
 653                       copy_range,
 654                       queue_total,
 655                       queue_maxlen,
 656                       queue_dropped,
 657                       queue_user_dropped);
 658
 659         read_unlock_bh(&queue_lock);
 660
 661         *start = buffer + offset;
 662         len -= offset;
 663         if (len > length)
 664                 len = length;
 665         else if (len < 0)
 666                 len = 0;
 667         return len;
 668 }
 669 #endif /* CONFIG_PROC_FS */
 670
 671 static struct nf_queue_handler nfqh = {
 672         .name   = "ip_queue",
 673         .outfn  = &ipq_enqueue_packet,
 674 };
 675
 676 static int __init ip_queue_init(void)
 677 {
 678         int status = -ENOMEM;
 679         struct proc_dir_entry *proc;
 680
 681         netlink_register_notifier(&ipq_nl_notifier);
 682         ipqnl = netlink_kernel_create(NETLINK_FIREWALL, 0, ipq_rcv_sk,
 683                                       THIS_MODULE);
 684         if (ipqnl == NULL) {
 685                 printk(KERN_ERR "ip_queue: failed to create netlink socket\n");
 686                 goto cleanup_netlink_notifier;
 687         }
 688
 689         proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
 690         if (proc)
 691                 proc->owner = THIS_MODULE;
 692         else {
 693                 printk(KERN_ERR "ip_queue: failed to create proc entry\n");
 694                 goto cleanup_ipqnl;
 695         }
 696
 697         register_netdevice_notifier(&ipq_dev_notifier);
 698         ipq_sysctl_header = register_sysctl_table(ipq_root_table);
 699
 700         status = nf_register_queue_handler(PF_INET, &nfqh);
 701         if (status < 0) {
 702                 printk(KERN_ERR "ip_queue: failed to register queue handler\n");
 703                 goto cleanup_sysctl;
 704         }
 705         return status;
 706
 707 cleanup_sysctl:
 708         unregister_sysctl_table(ipq_sysctl_header);
 709         unregister_netdevice_notifier(&ipq_dev_notifier);
 710         proc_net_remove(IPQ_PROC_FS_NAME);
 711
 712 cleanup_ipqnl:
 713         sock_release(ipqnl->sk_socket);
 714         mutex_lock(&ipqnl_mutex);
 715         mutex_unlock(&ipqnl_mutex);
 716
 717 cleanup_netlink_notifier:
 718         netlink_unregister_notifier(&ipq_nl_notifier);
 719         return status;
 720 }
 721
 722 static void __exit ip_queue_fini(void)
 723 {
 724         nf_unregister_queue_handlers(&nfqh);
 725         synchronize_net();
 726         ipq_flush(NF_DROP);
 727
 728         unregister_sysctl_table(ipq_sysctl_header);
 729         unregister_netdevice_notifier(&ipq_dev_notifier);
 730         proc_net_remove(IPQ_PROC_FS_NAME);
 731
 732         sock_release(ipqnl->sk_socket);
 733         mutex_lock(&ipqnl_mutex);
 734         mutex_unlock(&ipqnl_mutex);
 735
 736         netlink_unregister_notifier(&ipq_nl_notifier);
 737 }
 738
 739 MODULE_DESCRIPTION("IPv4 packet queue handler");
 740 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
 741 MODULE_LICENSE("GPL");
 742
 743 module_init(ip_queue_init);
 744 module_exit(ip_queue_fini);