net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c

   1
   2 /* (C) 1999-2001 Paul `Rusty' Russell
   3  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   4  * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/ip.h>
  13 #include <linux/netfilter.h>
  14 #include <linux/module.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/icmp.h>
  17 #include <linux/sysctl.h>
  18 #include <net/route.h>
  19 #include <net/ip.h>
  20
  21 #include <linux/netfilter_ipv4.h>
  22 #include <net/netfilter/nf_conntrack.h>
  23 #include <net/netfilter/nf_conntrack_helper.h>
  24 #include <net/netfilter/nf_conntrack_l4proto.h>
  25 #include <net/netfilter/nf_conntrack_l3proto.h>
  26 #include <net/netfilter/nf_conntrack_zones.h>
  27 #include <net/netfilter/nf_conntrack_core.h>
  28 #include <net/netfilter/nf_conntrack_seqadj.h>
  29 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
  30 #include <net/netfilter/nf_nat_helper.h>
  31 #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
  32 #include <net/netfilter/nf_log.h>
  33
  34 static bool ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
  35                               struct nf_conntrack_tuple *tuple)
  36 {
  37         const __be32 *ap;
  38         __be32 _addrs[2];
  39         ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
  40                                 sizeof(u_int32_t) * 2, _addrs);
  41         if (ap == NULL)
  42                 return false;
  43
  44         tuple->src.u3.ip = ap[0];
  45         tuple->dst.u3.ip = ap[1];
  46
  47         return true;
  48 }
  49
  50 static bool ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
  51                               const struct nf_conntrack_tuple *orig)
  52 {
  53         tuple->src.u3.ip = orig->dst.u3.ip;
  54         tuple->dst.u3.ip = orig->src.u3.ip;
  55
  56         return true;
  57 }
  58
  59 static void ipv4_print_tuple(struct seq_file *s,
  60                             const struct nf_conntrack_tuple *tuple)
  61 {
  62         seq_printf(s, "src=%pI4 dst=%pI4 ",
  63                    &tuple->src.u3.ip, &tuple->dst.u3.ip);
  64 }
  65
  66 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
  67                             unsigned int *dataoff, u_int8_t *protonum)
  68 {
  69         const struct iphdr *iph;
  70         struct iphdr _iph;
  71
  72         iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
  73         if (iph == NULL)
  74                 return -NF_ACCEPT;
  75
  76         /* Conntrack defragments packets, we might still see fragments
  77          * inside ICMP packets though. */
  78         if (iph->frag_off & htons(IP_OFFSET))
  79                 return -NF_ACCEPT;
  80
  81         *dataoff = nhoff + (iph->ihl << 2);
  82         *protonum = iph->protocol;
  83
  84         /* Check bogus IP headers */
  85         if (*dataoff > skb->len) {
  86                 pr_debug("nf_conntrack_ipv4: bogus IPv4 packet: "
  87                          "nhoff %u, ihl %u, skblen %u\n",
  88                          nhoff, iph->ihl << 2, skb->len);
  89                 return -NF_ACCEPT;
  90         }
  91
  92         return NF_ACCEPT;
  93 }
  94
  95 static unsigned int ipv4_helper(const struct nf_hook_ops *ops,
  96                                 struct sk_buff *skb,
  97                                 const struct net_device *in,
  98                                 const struct net_device *out,
  99                                 int (*okfn)(struct sk_buff *))
 100 {
 101         struct nf_conn *ct;
 102         enum ip_conntrack_info ctinfo;
 103         const struct nf_conn_help *help;
 104         const struct nf_conntrack_helper *helper;
 105
 106         /* This is where we call the helper: as the packet goes out. */
 107         ct = nf_ct_get(skb, &ctinfo);
 108         if (!ct || ctinfo == IP_CT_RELATED_REPLY)
 109                 return NF_ACCEPT;
 110
 111         help = nfct_help(ct);
 112         if (!help)
 113                 return NF_ACCEPT;
 114
 115         /* rcu_read_lock()ed by nf_hook_slow */
 116         helper = rcu_dereference(help->helper);
 117         if (!helper)
 118                 return NF_ACCEPT;
 119
 120         return helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
 121                             ct, ctinfo);
 122 }
 123
 124 static unsigned int ipv4_confirm(const struct nf_hook_ops *ops,
 125                                  struct sk_buff *skb,
 126                                  const struct net_device *in,
 127                                  const struct net_device *out,
 128                                  int (*okfn)(struct sk_buff *))
 129 {
 130         struct nf_conn *ct;
 131         enum ip_conntrack_info ctinfo;
 132
 133         ct = nf_ct_get(skb, &ctinfo);
 134         if (!ct || ctinfo == IP_CT_RELATED_REPLY)
 135                 goto out;
 136
 137         /* adjust seqs for loopback traffic only in outgoing direction */
 138         if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
 139             !nf_is_loopback_packet(skb)) {
 140                 if (!nf_ct_seq_adjust(skb, ct, ctinfo, ip_hdrlen(skb))) {
 141                         NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
 142                         return NF_DROP;
 143                 }
 144         }
 145 out:
 146         /* We've seen it coming out the other side: confirm it */
 147         return nf_conntrack_confirm(skb);
 148 }
 149
 150 static unsigned int ipv4_conntrack_in(const struct nf_hook_ops *ops,
 151                                       struct sk_buff *skb,
 152                                       const struct net_device *in,
 153                                       const struct net_device *out,
 154                                       int (*okfn)(struct sk_buff *))
 155 {
 156         return nf_conntrack_in(dev_net(in), PF_INET, ops->hooknum, skb);
 157 }
 158
 159 static unsigned int ipv4_conntrack_local(const struct nf_hook_ops *ops,
 160                                          struct sk_buff *skb,
 161                                          const struct net_device *in,
 162                                          const struct net_device *out,
 163                                          int (*okfn)(struct sk_buff *))
 164 {
 165         /* root is playing with raw sockets. */
 166         if (skb->len < sizeof(struct iphdr) ||
 167             ip_hdrlen(skb) < sizeof(struct iphdr))
 168                 return NF_ACCEPT;
 169         return nf_conntrack_in(dev_net(out), PF_INET, ops->hooknum, skb);
 170 }
 171
 172 /* Connection tracking may drop packets, but never alters them, so
 173    make it the first hook. */
 174 static struct nf_hook_ops ipv4_conntrack_ops[] __read_mostly = {
 175         {
 176                 .hook           = ipv4_conntrack_in,
 177                 .owner          = THIS_MODULE,
 178                 .pf             = NFPROTO_IPV4,
 179                 .hooknum        = NF_INET_PRE_ROUTING,
 180                 .priority       = NF_IP_PRI_CONNTRACK,
 181         },
 182         {
 183                 .hook           = ipv4_conntrack_local,
 184                 .owner          = THIS_MODULE,
 185                 .pf             = NFPROTO_IPV4,
 186                 .hooknum        = NF_INET_LOCAL_OUT,
 187                 .priority       = NF_IP_PRI_CONNTRACK,
 188         },
 189         {
 190                 .hook           = ipv4_helper,
 191                 .owner          = THIS_MODULE,
 192                 .pf             = NFPROTO_IPV4,
 193                 .hooknum        = NF_INET_POST_ROUTING,
 194                 .priority       = NF_IP_PRI_CONNTRACK_HELPER,
 195         },
 196         {
 197                 .hook           = ipv4_confirm,
 198                 .owner          = THIS_MODULE,
 199                 .pf             = NFPROTO_IPV4,
 200                 .hooknum        = NF_INET_POST_ROUTING,
 201                 .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
 202         },
 203         {
 204                 .hook           = ipv4_helper,
 205                 .owner          = THIS_MODULE,
 206                 .pf             = NFPROTO_IPV4,
 207                 .hooknum        = NF_INET_LOCAL_IN,
 208                 .priority       = NF_IP_PRI_CONNTRACK_HELPER,
 209         },
 210         {
 211                 .hook           = ipv4_confirm,
 212                 .owner          = THIS_MODULE,
 213                 .pf             = NFPROTO_IPV4,
 214                 .hooknum        = NF_INET_LOCAL_IN,
 215                 .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
 216         },
 217 };
 218
 219 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 220 static int log_invalid_proto_min = 0;
 221 static int log_invalid_proto_max = 255;
 222
 223 static struct ctl_table ip_ct_sysctl_table[] = {
 224         {
 225                 .procname       = "ip_conntrack_max",
 226                 .maxlen         = sizeof(int),
 227                 .mode           = 0644,
 228                 .proc_handler   = proc_dointvec,
 229         },
 230         {
 231                 .procname       = "ip_conntrack_count",
 232                 .maxlen         = sizeof(int),
 233                 .mode           = 0444,
 234                 .proc_handler   = proc_dointvec,
 235         },
 236         {
 237                 .procname       = "ip_conntrack_buckets",
 238                 .maxlen         = sizeof(unsigned int),
 239                 .mode           = 0444,
 240                 .proc_handler   = proc_dointvec,
 241         },
 242         {
 243                 .procname       = "ip_conntrack_checksum",
 244                 .maxlen         = sizeof(int),
 245                 .mode           = 0644,
 246                 .proc_handler   = proc_dointvec,
 247         },
 248         {
 249                 .procname       = "ip_conntrack_log_invalid",
 250                 .maxlen         = sizeof(unsigned int),
 251                 .mode           = 0644,
 252                 .proc_handler   = proc_dointvec_minmax,
 253                 .extra1         = &log_invalid_proto_min,
 254                 .extra2         = &log_invalid_proto_max,
 255         },
 256         { }
 257 };
 258 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
 259
 260 /* Fast function for those who don't want to parse /proc (and I don't
 261    blame them). */
 262 /* Reversing the socket's dst/src point of view gives us the reply
 263    mapping. */
 264 static int
 265 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
 266 {
 267         const struct inet_sock *inet = inet_sk(sk);
 268         const struct nf_conntrack_tuple_hash *h;
 269         struct nf_conntrack_tuple tuple;
 270
 271         memset(&tuple, 0, sizeof(tuple));
 272         tuple.src.u3.ip = inet->inet_rcv_saddr;
 273         tuple.src.u.tcp.port = inet->inet_sport;
 274         tuple.dst.u3.ip = inet->inet_daddr;
 275         tuple.dst.u.tcp.port = inet->inet_dport;
 276         tuple.src.l3num = PF_INET;
 277         tuple.dst.protonum = sk->sk_protocol;
 278
 279         /* We only do TCP and SCTP at the moment: is there a better way? */
 280         if (sk->sk_protocol != IPPROTO_TCP && sk->sk_protocol != IPPROTO_SCTP) {
 281                 pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n");
 282                 return -ENOPROTOOPT;
 283         }
 284
 285         if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
 286                 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
 287                          *len, sizeof(struct sockaddr_in));
 288                 return -EINVAL;
 289         }
 290
 291         h = nf_conntrack_find_get(sock_net(sk), NF_CT_DEFAULT_ZONE, &tuple);
 292         if (h) {
 293                 struct sockaddr_in sin;
 294                 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 295
 296                 sin.sin_family = AF_INET;
 297                 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
 298                         .tuple.dst.u.tcp.port;
 299                 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
 300                         .tuple.dst.u3.ip;
 301                 memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
 302
 303                 pr_debug("SO_ORIGINAL_DST: %pI4 %u\n",
 304                          &sin.sin_addr.s_addr, ntohs(sin.sin_port));
 305                 nf_ct_put(ct);
 306                 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
 307                         return -EFAULT;
 308                 else
 309                         return 0;
 310         }
 311         pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n",
 312                  &tuple.src.u3.ip, ntohs(tuple.src.u.tcp.port),
 313                  &tuple.dst.u3.ip, ntohs(tuple.dst.u.tcp.port));
 314         return -ENOENT;
 315 }
 316
 317 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 318
 319 #include <linux/netfilter/nfnetlink.h>
 320 #include <linux/netfilter/nfnetlink_conntrack.h>
 321
 322 static int ipv4_tuple_to_nlattr(struct sk_buff *skb,
 323                                 const struct nf_conntrack_tuple *tuple)
 324 {
 325         if (nla_put_in_addr(skb, CTA_IP_V4_SRC, tuple->src.u3.ip) ||
 326             nla_put_in_addr(skb, CTA_IP_V4_DST, tuple->dst.u3.ip))
 327                 goto nla_put_failure;
 328         return 0;
 329
 330 nla_put_failure:
 331         return -1;
 332 }
 333
 334 static const struct nla_policy ipv4_nla_policy[CTA_IP_MAX+1] = {
 335         [CTA_IP_V4_SRC] = { .type = NLA_U32 },
 336         [CTA_IP_V4_DST] = { .type = NLA_U32 },
 337 };
 338
 339 static int ipv4_nlattr_to_tuple(struct nlattr *tb[],
 340                                 struct nf_conntrack_tuple *t)
 341 {
 342         if (!tb[CTA_IP_V4_SRC] || !tb[CTA_IP_V4_DST])
 343                 return -EINVAL;
 344
 345         t->src.u3.ip = nla_get_be32(tb[CTA_IP_V4_SRC]);
 346         t->dst.u3.ip = nla_get_be32(tb[CTA_IP_V4_DST]);
 347
 348         return 0;
 349 }
 350
 351 static int ipv4_nlattr_tuple_size(void)
 352 {
 353         return nla_policy_len(ipv4_nla_policy, CTA_IP_MAX + 1);
 354 }
 355 #endif
 356
 357 static struct nf_sockopt_ops so_getorigdst = {
 358         .pf             = PF_INET,
 359         .get_optmin     = SO_ORIGINAL_DST,
 360         .get_optmax     = SO_ORIGINAL_DST+1,
 361         .get            = getorigdst,
 362         .owner          = THIS_MODULE,
 363 };
 364
 365 static int ipv4_init_net(struct net *net)
 366 {
 367 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 368         struct nf_ip_net *in = &net->ct.nf_ct_proto;
 369         in->ctl_table = kmemdup(ip_ct_sysctl_table,
 370                                 sizeof(ip_ct_sysctl_table),
 371                                 GFP_KERNEL);
 372         if (!in->ctl_table)
 373                 return -ENOMEM;
 374
 375         in->ctl_table[0].data = &nf_conntrack_max;
 376         in->ctl_table[1].data = &net->ct.count;
 377         in->ctl_table[2].data = &net->ct.htable_size;
 378         in->ctl_table[3].data = &net->ct.sysctl_checksum;
 379         in->ctl_table[4].data = &net->ct.sysctl_log_invalid;
 380 #endif
 381         return 0;
 382 }
 383
 384 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly = {
 385         .l3proto         = PF_INET,
 386         .name            = "ipv4",
 387         .pkt_to_tuple    = ipv4_pkt_to_tuple,
 388         .invert_tuple    = ipv4_invert_tuple,
 389         .print_tuple     = ipv4_print_tuple,
 390         .get_l4proto     = ipv4_get_l4proto,
 391 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 392         .tuple_to_nlattr = ipv4_tuple_to_nlattr,
 393         .nlattr_tuple_size = ipv4_nlattr_tuple_size,
 394         .nlattr_to_tuple = ipv4_nlattr_to_tuple,
 395         .nla_policy      = ipv4_nla_policy,
 396 #endif
 397 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 398         .ctl_table_path  = "net/ipv4/netfilter",
 399 #endif
 400         .init_net        = ipv4_init_net,
 401         .me              = THIS_MODULE,
 402 };
 403
 404 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
 405                   &nf_conntrack_htable_size, 0600);
 406
 407 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
 408 MODULE_ALIAS("ip_conntrack");
 409 MODULE_LICENSE("GPL");
 410
 411 static int ipv4_net_init(struct net *net)
 412 {
 413         int ret = 0;
 414
 415         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_tcp4);
 416         if (ret < 0) {
 417                 pr_err("nf_conntrack_tcp4: pernet registration failed\n");
 418                 goto out_tcp;
 419         }
 420         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udp4);
 421         if (ret < 0) {
 422                 pr_err("nf_conntrack_udp4: pernet registration failed\n");
 423                 goto out_udp;
 424         }
 425         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_icmp);
 426         if (ret < 0) {
 427                 pr_err("nf_conntrack_icmp4: pernet registration failed\n");
 428                 goto out_icmp;
 429         }
 430         ret = nf_ct_l3proto_pernet_register(net, &nf_conntrack_l3proto_ipv4);
 431         if (ret < 0) {
 432                 pr_err("nf_conntrack_ipv4: pernet registration failed\n");
 433                 goto out_ipv4;
 434         }
 435         return 0;
 436 out_ipv4:
 437         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmp);
 438 out_icmp:
 439         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp4);
 440 out_udp:
 441         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp4);
 442 out_tcp:
 443         return ret;
 444 }
 445
 446 static void ipv4_net_exit(struct net *net)
 447 {
 448         nf_ct_l3proto_pernet_unregister(net, &nf_conntrack_l3proto_ipv4);
 449         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmp);
 450         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp4);
 451         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp4);
 452 }
 453
 454 static struct pernet_operations ipv4_net_ops = {
 455         .init = ipv4_net_init,
 456         .exit = ipv4_net_exit,
 457 };
 458
 459 static int __init nf_conntrack_l3proto_ipv4_init(void)
 460 {
 461         int ret = 0;
 462
 463         need_conntrack();
 464         nf_defrag_ipv4_enable();
 465
 466         ret = nf_register_sockopt(&so_getorigdst);
 467         if (ret < 0) {
 468                 printk(KERN_ERR "Unable to register netfilter socket option\n");
 469                 return ret;
 470         }
 471
 472         ret = register_pernet_subsys(&ipv4_net_ops);
 473         if (ret < 0) {
 474                 pr_err("nf_conntrack_ipv4: can't register pernet ops\n");
 475                 goto cleanup_sockopt;
 476         }
 477
 478         ret = nf_register_hooks(ipv4_conntrack_ops,
 479                                 ARRAY_SIZE(ipv4_conntrack_ops));
 480         if (ret < 0) {
 481                 pr_err("nf_conntrack_ipv4: can't register hooks.\n");
 482                 goto cleanup_pernet;
 483         }
 484
 485         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_tcp4);
 486         if (ret < 0) {
 487                 pr_err("nf_conntrack_ipv4: can't register tcp4 proto.\n");
 488                 goto cleanup_hooks;
 489         }
 490
 491         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udp4);
 492         if (ret < 0) {
 493                 pr_err("nf_conntrack_ipv4: can't register udp4 proto.\n");
 494                 goto cleanup_tcp4;
 495         }
 496
 497         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_icmp);
 498         if (ret < 0) {
 499                 pr_err("nf_conntrack_ipv4: can't register icmpv4 proto.\n");
 500                 goto cleanup_udp4;
 501         }
 502
 503         ret = nf_ct_l3proto_register(&nf_conntrack_l3proto_ipv4);
 504         if (ret < 0) {
 505                 pr_err("nf_conntrack_ipv4: can't register ipv4 proto.\n");
 506                 goto cleanup_icmpv4;
 507         }
 508
 509 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 510         ret = nf_conntrack_ipv4_compat_init();
 511         if (ret < 0)
 512                 goto cleanup_proto;
 513 #endif
 514         return ret;
 515 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 516  cleanup_proto:
 517         nf_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
 518 #endif
 519  cleanup_icmpv4:
 520         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmp);
 521  cleanup_udp4:
 522         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp4);
 523  cleanup_tcp4:
 524         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
 525  cleanup_hooks:
 526         nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
 527  cleanup_pernet:
 528         unregister_pernet_subsys(&ipv4_net_ops);
 529  cleanup_sockopt:
 530         nf_unregister_sockopt(&so_getorigdst);
 531         return ret;
 532 }
 533
 534 static void __exit nf_conntrack_l3proto_ipv4_fini(void)
 535 {
 536         synchronize_net();
 537 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 538         nf_conntrack_ipv4_compat_fini();
 539 #endif
 540         nf_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
 541         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmp);
 542         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp4);
 543         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
 544         nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
 545         unregister_pernet_subsys(&ipv4_net_ops);
 546         nf_unregister_sockopt(&so_getorigdst);
 547 }
 548
 549 module_init(nf_conntrack_l3proto_ipv4_init);
 550 module_exit(nf_conntrack_l3proto_ipv4_fini);