net/ipv6/netfilter/ip6_queue.c

   1 /*
   2  * This is a module which is used for queueing IPv6 packets and
   3  * communicating with userspace via netlink.
   4  *
   5  * (C) 2001 Fernando Anton, this code is GPL.
   6  *     IPv64 Project - Work based in IPv64 draft by Arturo Azcorra.
   7  *     Universidad Carlos III de Madrid - Leganes (Madrid) - Spain
   8  *     Universidad Politecnica de Alcala de Henares - Alcala de H. (Madrid) - Spain
   9  *     email: fanton@it.uc3m.es
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  *
  15  * 2001-11-06: First try. Working with ip_queue.c for IPv4 and trying
  16  *             to adapt it to IPv6
  17  *             HEAVILY based in ipqueue.c by James Morris. It's just
  18  *             a little modified version of it, so he's nearly the
  19  *             real coder of this.
  20  *             Few changes needed, mainly the hard_routing code and
  21  *             the netlink socket protocol (we're NETLINK_IP6_FW).
  22  * 2002-06-25: Code cleanup. [JM: ported cleanup over from ip_queue.c]
  23  * 2005-02-04: Added /proc counter for dropped packets; fixed so
  24  *             packets aren't delivered to user space if they're going
  25  *             to be dropped.
  26  */
  27 #include <linux/module.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/init.h>
  30 #include <linux/ipv6.h>
  31 #include <linux/notifier.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/netfilter.h>
  34 #include <linux/netlink.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/sysctl.h>
  37 #include <linux/proc_fs.h>
  38 #include <net/sock.h>
  39 #include <net/ipv6.h>
  40 #include <net/ip6_route.h>
  41 #include <linux/netfilter_ipv4/ip_queue.h>
  42 #include <linux/netfilter_ipv4/ip_tables.h>
  43 #include <linux/netfilter_ipv6/ip6_tables.h>
  44
  45 #define IPQ_QMAX_DEFAULT 1024
  46 #define IPQ_PROC_FS_NAME "ip6_queue"
  47 #define NET_IPQ_QMAX 2088
  48 #define NET_IPQ_QMAX_NAME "ip6_queue_maxlen"
  49
  50 struct ipq_rt_info {
  51         struct in6_addr daddr;
  52         struct in6_addr saddr;
  53 };
  54
  55 struct ipq_queue_entry {
  56         struct list_head list;
  57         struct nf_info *info;
  58         struct sk_buff *skb;
  59         struct ipq_rt_info rt_info;
  60 };
  61
  62 typedef int (*ipq_cmpfn)(struct ipq_queue_entry *, unsigned long);
  63
  64 static unsigned char copy_mode = IPQ_COPY_NONE;
  65 static unsigned int queue_maxlen = IPQ_QMAX_DEFAULT;
  66 static DEFINE_RWLOCK(queue_lock);
  67 static int peer_pid;
  68 static unsigned int copy_range;
  69 static unsigned int queue_total;
  70 static unsigned int queue_dropped = 0;
  71 static unsigned int queue_user_dropped = 0;
  72 static struct sock *ipqnl;
  73 static LIST_HEAD(queue_list);
  74 static DECLARE_MUTEX(ipqnl_sem);
  75
  76 static void
  77 ipq_issue_verdict(struct ipq_queue_entry *entry, int verdict)
  78 {
  79         nf_reinject(entry->skb, entry->info, verdict);
  80         kfree(entry);
  81 }
  82
  83 static inline void
  84 __ipq_enqueue_entry(struct ipq_queue_entry *entry)
  85 {
  86        list_add(&entry->list, &queue_list);
  87        queue_total++;
  88 }
  89
  90 /*
  91  * Find and return a queued entry matched by cmpfn, or return the last
  92  * entry if cmpfn is NULL.
  93  */
  94 static inline struct ipq_queue_entry *
  95 __ipq_find_entry(ipq_cmpfn cmpfn, unsigned long data)
  96 {
  97         struct list_head *p;
  98
  99         list_for_each_prev(p, &queue_list) {
 100                 struct ipq_queue_entry *entry = (struct ipq_queue_entry *)p;
 101
 102                 if (!cmpfn || cmpfn(entry, data))
 103                         return entry;
 104         }
 105         return NULL;
 106 }
 107
 108 static inline void
 109 __ipq_dequeue_entry(struct ipq_queue_entry *entry)
 110 {
 111         list_del(&entry->list);
 112         queue_total--;
 113 }
 114
 115 static inline struct ipq_queue_entry *
 116 __ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 117 {
 118         struct ipq_queue_entry *entry;
 119
 120         entry = __ipq_find_entry(cmpfn, data);
 121         if (entry == NULL)
 122                 return NULL;
 123
 124         __ipq_dequeue_entry(entry);
 125         return entry;
 126 }
 127
 128
 129 static inline void
 130 __ipq_flush(int verdict)
 131 {
 132         struct ipq_queue_entry *entry;
 133
 134         while ((entry = __ipq_find_dequeue_entry(NULL, 0)))
 135                 ipq_issue_verdict(entry, verdict);
 136 }
 137
 138 static inline int
 139 __ipq_set_mode(unsigned char mode, unsigned int range)
 140 {
 141         int status = 0;
 142
 143         switch(mode) {
 144         case IPQ_COPY_NONE:
 145         case IPQ_COPY_META:
 146                 copy_mode = mode;
 147                 copy_range = 0;
 148                 break;
 149
 150         case IPQ_COPY_PACKET:
 151                 copy_mode = mode;
 152                 copy_range = range;
 153                 if (copy_range > 0xFFFF)
 154                         copy_range = 0xFFFF;
 155                 break;
 156
 157         default:
 158                 status = -EINVAL;
 159
 160         }
 161         return status;
 162 }
 163
 164 static inline void
 165 __ipq_reset(void)
 166 {
 167         peer_pid = 0;
 168         net_disable_timestamp();
 169         __ipq_set_mode(IPQ_COPY_NONE, 0);
 170         __ipq_flush(NF_DROP);
 171 }
 172
 173 static struct ipq_queue_entry *
 174 ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
 175 {
 176         struct ipq_queue_entry *entry;
 177
 178         write_lock_bh(&queue_lock);
 179         entry = __ipq_find_dequeue_entry(cmpfn, data);
 180         write_unlock_bh(&queue_lock);
 181         return entry;
 182 }
 183
 184 static void
 185 ipq_flush(int verdict)
 186 {
 187         write_lock_bh(&queue_lock);
 188         __ipq_flush(verdict);
 189         write_unlock_bh(&queue_lock);
 190 }
 191
 192 static struct sk_buff *
 193 ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
 194 {
 195         unsigned char *old_tail;
 196         size_t size = 0;
 197         size_t data_len = 0;
 198         struct sk_buff *skb;
 199         struct ipq_packet_msg *pmsg;
 200         struct nlmsghdr *nlh;
 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 (copy_range == 0 || copy_range > entry->skb->len)
 213                         data_len = entry->skb->len;
 214                 else
 215                         data_len = copy_range;
 216
 217                 size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
 218                 break;
 219
 220         default:
 221                 *errp = -EINVAL;
 222                 read_unlock_bh(&queue_lock);
 223                 return NULL;
 224         }
 225
 226         read_unlock_bh(&queue_lock);
 227
 228         skb = alloc_skb(size, GFP_ATOMIC);
 229         if (!skb)
 230                 goto nlmsg_failure;
 231
 232         old_tail= skb->tail;
 233         nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
 234         pmsg = NLMSG_DATA(nlh);
 235         memset(pmsg, 0, sizeof(*pmsg));
 236
 237         pmsg->packet_id       = (unsigned long )entry;
 238         pmsg->data_len        = data_len;
 239         pmsg->timestamp_sec   = entry->skb->stamp.tv_sec;
 240         pmsg->timestamp_usec  = entry->skb->stamp.tv_usec;
 241         pmsg->mark            = entry->skb->nfmark;
 242         pmsg->hook            = entry->info->hook;
 243         pmsg->hw_protocol     = entry->skb->protocol;
 244
 245         if (entry->info->indev)
 246                 strcpy(pmsg->indev_name, entry->info->indev->name);
 247         else
 248                 pmsg->indev_name[0] = '\0';
 249
 250         if (entry->info->outdev)
 251                 strcpy(pmsg->outdev_name, entry->info->outdev->name);
 252         else
 253                 pmsg->outdev_name[0] = '\0';
 254
 255         if (entry->info->indev && entry->skb->dev) {
 256                 pmsg->hw_type = entry->skb->dev->type;
 257                 if (entry->skb->dev->hard_header_parse)
 258                         pmsg->hw_addrlen =
 259                                 entry->skb->dev->hard_header_parse(entry->skb,
 260                                                                    pmsg->hw_addr);
 261         }
 262
 263         if (data_len)
 264                 if (skb_copy_bits(entry->skb, 0, pmsg->payload, data_len))
 265                         BUG();
 266
 267         nlh->nlmsg_len = skb->tail - old_tail;
 268         return skb;
 269
 270 nlmsg_failure:
 271         if (skb)
 272                 kfree_skb(skb);
 273         *errp = -EINVAL;
 274         printk(KERN_ERR "ip6_queue: error creating packet message\n");
 275         return NULL;
 276 }
 277
 278 static int
 279 ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, void *data)
 280 {
 281         int status = -EINVAL;
 282         struct sk_buff *nskb;
 283         struct ipq_queue_entry *entry;
 284
 285         if (copy_mode == IPQ_COPY_NONE)
 286                 return -EAGAIN;
 287
 288         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 289         if (entry == NULL) {
 290                 printk(KERN_ERR "ip6_queue: OOM in ipq_enqueue_packet()\n");
 291                 return -ENOMEM;
 292         }
 293
 294         entry->info = info;
 295         entry->skb = skb;
 296
 297         if (entry->info->hook == NF_IP_LOCAL_OUT) {
 298                 struct ipv6hdr *iph = skb->nh.ipv6h;
 299
 300                 entry->rt_info.daddr = iph->daddr;
 301                 entry->rt_info.saddr = iph->saddr;
 302         }
 303
 304         nskb = ipq_build_packet_message(entry, &status);
 305         if (nskb == NULL)
 306                 goto err_out_free;
 307
 308         write_lock_bh(&queue_lock);
 309
 310         if (!peer_pid)
 311                 goto err_out_free_nskb;
 312
 313         if (queue_total >= queue_maxlen) {
 314                 queue_dropped++;
 315                 status = -ENOSPC;
 316                 if (net_ratelimit())
 317                         printk (KERN_WARNING "ip6_queue: fill at %d entries, "
 318                                 "dropping packet(s).  Dropped: %d\n", queue_total,
 319                                 queue_dropped);
 320                 goto err_out_free_nskb;
 321         }
 322
 323         /* netlink_unicast will either free the nskb or attach it to a socket */
 324         status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
 325         if (status < 0) {
 326                 queue_user_dropped++;
 327                 goto err_out_unlock;
 328         }
 329
 330         __ipq_enqueue_entry(entry);
 331
 332         write_unlock_bh(&queue_lock);
 333         return status;
 334
 335 err_out_free_nskb:
 336         kfree_skb(nskb);
 337
 338 err_out_unlock:
 339         write_unlock_bh(&queue_lock);
 340
 341 err_out_free:
 342         kfree(entry);
 343         return status;
 344 }
 345
 346 static int
 347 ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
 348 {
 349         int diff;
 350         struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload;
 351
 352         if (v->data_len < sizeof(*user_iph))
 353                 return 0;
 354         diff = v->data_len - e->skb->len;
 355         if (diff < 0)
 356                 skb_trim(e->skb, v->data_len);
 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 "ip6_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_ip_make_writable(&e->skb, v->data_len))
 380                 return -ENOMEM;
 381         memcpy(e->skb->data, v->payload, v->data_len);
 382         e->skb->nfcache |= NFC_ALTERED;
 383
 384         /*
 385          * Extra routing may needed on local out, as the QUEUE target never
 386          * returns control to the table.
 387          * Not a nice way to cmp, but works
 388          */
 389         if (e->info->hook == NF_IP_LOCAL_OUT) {
 390                 struct ipv6hdr *iph = e->skb->nh.ipv6h;
 391                 if (!ipv6_addr_equal(&iph->daddr, &e->rt_info.daddr) ||
 392                     !ipv6_addr_equal(&iph->saddr, &e->rt_info.saddr))
 393                         return ip6_route_me_harder(e->skb);
 394         }
 395         return 0;
 396 }
 397
 398 static inline int
 399 id_cmp(struct ipq_queue_entry *e, unsigned long id)
 400 {
 401         return (id == (unsigned long )e);
 402 }
 403
 404 static int
 405 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
 406 {
 407         struct ipq_queue_entry *entry;
 408
 409         if (vmsg->value > NF_MAX_VERDICT)
 410                 return -EINVAL;
 411
 412         entry = ipq_find_dequeue_entry(id_cmp, vmsg->id);
 413         if (entry == NULL)
 414                 return -ENOENT;
 415         else {
 416                 int verdict = vmsg->value;
 417
 418                 if (vmsg->data_len && vmsg->data_len == len)
 419                         if (ipq_mangle_ipv6(vmsg, entry) < 0)
 420                                 verdict = NF_DROP;
 421
 422                 ipq_issue_verdict(entry, verdict);
 423                 return 0;
 424         }
 425 }
 426
 427 static int
 428 ipq_set_mode(unsigned char mode, unsigned int range)
 429 {
 430         int status;
 431
 432         write_lock_bh(&queue_lock);
 433         status = __ipq_set_mode(mode, range);
 434         write_unlock_bh(&queue_lock);
 435         return status;
 436 }
 437
 438 static int
 439 ipq_receive_peer(struct ipq_peer_msg *pmsg,
 440                  unsigned char type, unsigned int len)
 441 {
 442         int status = 0;
 443
 444         if (len < sizeof(*pmsg))
 445                 return -EINVAL;
 446
 447         switch (type) {
 448         case IPQM_MODE:
 449                 status = ipq_set_mode(pmsg->msg.mode.value,
 450                                       pmsg->msg.mode.range);
 451                 break;
 452
 453         case IPQM_VERDICT:
 454                 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
 455                         status = -EINVAL;
 456                 else
 457                         status = ipq_set_verdict(&pmsg->msg.verdict,
 458                                                  len - sizeof(*pmsg));
 459                         break;
 460         default:
 461                 status = -EINVAL;
 462         }
 463         return status;
 464 }
 465
 466 static int
 467 dev_cmp(struct ipq_queue_entry *entry, unsigned long ifindex)
 468 {
 469         if (entry->info->indev)
 470                 if (entry->info->indev->ifindex == ifindex)
 471                         return 1;
 472
 473         if (entry->info->outdev)
 474                 if (entry->info->outdev->ifindex == ifindex)
 475                         return 1;
 476
 477         return 0;
 478 }
 479
 480 static void
 481 ipq_dev_drop(int ifindex)
 482 {
 483         struct ipq_queue_entry *entry;
 484
 485         while ((entry = ipq_find_dequeue_entry(dev_cmp, ifindex)) != NULL)
 486                 ipq_issue_verdict(entry, NF_DROP);
 487 }
 488
 489 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 490
 491 static inline void
 492 ipq_rcv_skb(struct sk_buff *skb)
 493 {
 494         int status, type, pid, flags, nlmsglen, skblen;
 495         struct nlmsghdr *nlh;
 496
 497         skblen = skb->len;
 498         if (skblen < sizeof(*nlh))
 499                 return;
 500
 501         nlh = (struct nlmsghdr *)skb->data;
 502         nlmsglen = nlh->nlmsg_len;
 503         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
 504                 return;
 505
 506         pid = nlh->nlmsg_pid;
 507         flags = nlh->nlmsg_flags;
 508
 509         if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
 510                 RCV_SKB_FAIL(-EINVAL);
 511
 512         if (flags & MSG_TRUNC)
 513                 RCV_SKB_FAIL(-ECOMM);
 514
 515         type = nlh->nlmsg_type;
 516         if (type < NLMSG_NOOP || type >= IPQM_MAX)
 517                 RCV_SKB_FAIL(-EINVAL);
 518
 519         if (type <= IPQM_BASE)
 520                 return;
 521
 522         if (security_netlink_recv(skb))
 523                 RCV_SKB_FAIL(-EPERM);
 524
 525         write_lock_bh(&queue_lock);
 526
 527         if (peer_pid) {
 528                 if (peer_pid != pid) {
 529                         write_unlock_bh(&queue_lock);
 530                         RCV_SKB_FAIL(-EBUSY);
 531                 }
 532         } else {
 533                 net_enable_timestamp();
 534                 peer_pid = pid;
 535         }
 536
 537         write_unlock_bh(&queue_lock);
 538
 539         status = ipq_receive_peer(NLMSG_DATA(nlh), type,
 540                                   skblen - NLMSG_LENGTH(0));
 541         if (status < 0)
 542                 RCV_SKB_FAIL(status);
 543
 544         if (flags & NLM_F_ACK)
 545                 netlink_ack(skb, nlh, 0);
 546         return;
 547 }
 548
 549 static void
 550 ipq_rcv_sk(struct sock *sk, int len)
 551 {
 552         do {
 553                 struct sk_buff *skb;
 554
 555                 if (down_trylock(&ipqnl_sem))
 556                         return;
 557
 558                 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
 559                         ipq_rcv_skb(skb);
 560                         kfree_skb(skb);
 561                 }
 562
 563                 up(&ipqnl_sem);
 564
 565         } while (ipqnl && ipqnl->sk_receive_queue.qlen);
 566 }
 567
 568 static int
 569 ipq_rcv_dev_event(struct notifier_block *this,
 570                   unsigned long event, void *ptr)
 571 {
 572         struct net_device *dev = ptr;
 573
 574         /* Drop any packets associated with the downed device */
 575         if (event == NETDEV_DOWN)
 576                 ipq_dev_drop(dev->ifindex);
 577         return NOTIFY_DONE;
 578 }
 579
 580 static struct notifier_block ipq_dev_notifier = {
 581         .notifier_call  = ipq_rcv_dev_event,
 582 };
 583
 584 static int
 585 ipq_rcv_nl_event(struct notifier_block *this,
 586                  unsigned long event, void *ptr)
 587 {
 588         struct netlink_notify *n = ptr;
 589
 590         if (event == NETLINK_URELEASE &&
 591             n->protocol == NETLINK_IP6_FW && n->pid) {
 592                 write_lock_bh(&queue_lock);
 593                 if (n->pid == peer_pid)
 594                         __ipq_reset();
 595                 write_unlock_bh(&queue_lock);
 596         }
 597         return NOTIFY_DONE;
 598 }
 599
 600 static struct notifier_block ipq_nl_notifier = {
 601         .notifier_call  = ipq_rcv_nl_event,
 602 };
 603
 604 static struct ctl_table_header *ipq_sysctl_header;
 605
 606 static ctl_table ipq_table[] = {
 607         {
 608                 .ctl_name       = NET_IPQ_QMAX,
 609                 .procname       = NET_IPQ_QMAX_NAME,
 610                 .data           = &queue_maxlen,
 611                 .maxlen         = sizeof(queue_maxlen),
 612                 .mode           = 0644,
 613                 .proc_handler   = proc_dointvec
 614         },
 615         { .ctl_name = 0 }
 616 };
 617
 618 static ctl_table ipq_dir_table[] = {
 619         {
 620                 .ctl_name       = NET_IPV6,
 621                 .procname       = "ipv6",
 622                 .mode           = 0555,
 623                 .child          = ipq_table
 624         },
 625         { .ctl_name = 0 }
 626 };
 627
 628 static ctl_table ipq_root_table[] = {
 629         {
 630                 .ctl_name       = CTL_NET,
 631                 .procname       = "net",
 632                 .mode           = 0555,
 633                 .child          = ipq_dir_table
 634         },
 635         { .ctl_name = 0 }
 636 };
 637
 638 static int
 639 ipq_get_info(char *buffer, char **start, off_t offset, int length)
 640 {
 641         int len;
 642
 643         read_lock_bh(&queue_lock);
 644
 645         len = sprintf(buffer,
 646                       "Peer PID          : %d\n"
 647                       "Copy mode         : %hu\n"
 648                       "Copy range        : %u\n"
 649                       "Queue length      : %u\n"
 650                       "Queue max. length : %u\n"
 651                       "Queue dropped     : %u\n"
 652                       "Netfilter dropped : %u\n",
 653                       peer_pid,
 654                       copy_mode,
 655                       copy_range,
 656                       queue_total,
 657                       queue_maxlen,
 658                       queue_dropped,
 659                       queue_user_dropped);
 660
 661         read_unlock_bh(&queue_lock);
 662
 663         *start = buffer + offset;
 664         len -= offset;
 665         if (len > length)
 666                 len = length;
 667         else if (len < 0)
 668                 len = 0;
 669         return len;
 670 }
 671
 672 static int
 673 init_or_cleanup(int init)
 674 {
 675         int status = -ENOMEM;
 676         struct proc_dir_entry *proc;
 677
 678         if (!init)
 679                 goto cleanup;
 680
 681         netlink_register_notifier(&ipq_nl_notifier);
 682         ipqnl = netlink_kernel_create(NETLINK_IP6_FW, ipq_rcv_sk);
 683         if (ipqnl == NULL) {
 684                 printk(KERN_ERR "ip6_queue: failed to create netlink socket\n");
 685                 goto cleanup_netlink_notifier;
 686         }
 687
 688         proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
 689         if (proc)
 690                 proc->owner = THIS_MODULE;
 691         else {
 692                 printk(KERN_ERR "ip6_queue: failed to create proc entry\n");
 693                 goto cleanup_ipqnl;
 694         }
 695
 696         register_netdevice_notifier(&ipq_dev_notifier);
 697         ipq_sysctl_header = register_sysctl_table(ipq_root_table, 0);
 698
 699         status = nf_register_queue_handler(PF_INET6, ipq_enqueue_packet, NULL);
 700         if (status < 0) {
 701                 printk(KERN_ERR "ip6_queue: failed to register queue handler\n");
 702                 goto cleanup_sysctl;
 703         }
 704         return status;
 705
 706 cleanup:
 707         nf_unregister_queue_handler(PF_INET6);
 708         synchronize_net();
 709         ipq_flush(NF_DROP);
 710
 711 cleanup_sysctl:
 712         unregister_sysctl_table(ipq_sysctl_header);
 713         unregister_netdevice_notifier(&ipq_dev_notifier);
 714         proc_net_remove(IPQ_PROC_FS_NAME);
 715
 716 cleanup_ipqnl:
 717         sock_release(ipqnl->sk_socket);
 718         down(&ipqnl_sem);
 719         up(&ipqnl_sem);
 720
 721 cleanup_netlink_notifier:
 722         netlink_unregister_notifier(&ipq_nl_notifier);
 723         return status;
 724 }
 725
 726 static int __init init(void)
 727 {
 728
 729         return init_or_cleanup(1);
 730 }
 731
 732 static void __exit fini(void)
 733 {
 734         init_or_cleanup(0);
 735 }
 736
 737 MODULE_DESCRIPTION("IPv6 packet queue handler");
 738 MODULE_LICENSE("GPL");
 739
 740 module_init(init);
 741 module_exit(fini);