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/ipv4/nf_conntrack_ipv4.h>
  29 #include <net/netfilter/nf_nat_helper.h>
  30 #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
  31 #include <net/netfilter/nf_log.h>
  32
  33 static bool ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
  34                               struct nf_conntrack_tuple *tuple)
  35 {
  36         const __be32 *ap;
  37         __be32 _addrs[2];
  38         ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
  39                                 sizeof(u_int32_t) * 2, _addrs);
  40         if (ap == NULL)
  41                 return false;
  42
  43         tuple->src.u3.ip = ap[0];
  44         tuple->dst.u3.ip = ap[1];
  45
  46         return true;
  47 }
  48
  49 static bool ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
  50                               const struct nf_conntrack_tuple *orig)
  51 {
  52         tuple->src.u3.ip = orig->dst.u3.ip;
  53         tuple->dst.u3.ip = orig->src.u3.ip;
  54
  55         return true;
  56 }
  57
  58 static int ipv4_print_tuple(struct seq_file *s,
  59                             const struct nf_conntrack_tuple *tuple)
  60 {
  61         return seq_printf(s, "src=%pI4 dst=%pI4 ",
  62                           &tuple->src.u3.ip, &tuple->dst.u3.ip);
  63 }
  64
  65 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
  66                             unsigned int *dataoff, u_int8_t *protonum)
  67 {
  68         const struct iphdr *iph;
  69         struct iphdr _iph;
  70
  71         iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
  72         if (iph == NULL)
  73                 return -NF_ACCEPT;
  74
  75         /* Conntrack defragments packets, we might still see fragments
  76          * inside ICMP packets though. */
  77         if (iph->frag_off & htons(IP_OFFSET))
  78                 return -NF_ACCEPT;
  79
  80         *dataoff = nhoff + (iph->ihl << 2);
  81         *protonum = iph->protocol;
  82
  83         /* Check bogus IP headers */
  84         if (*dataoff > skb->len) {
  85                 pr_debug("nf_conntrack_ipv4: bogus IPv4 packet: "
  86                          "nhoff %u, ihl %u, skblen %u\n",
  87                          nhoff, iph->ihl << 2, skb->len);
  88                 return -NF_ACCEPT;
  89         }
  90
  91         return NF_ACCEPT;
  92 }
  93
  94 static unsigned int ipv4_helper(unsigned int hooknum,
  95                                 struct sk_buff *skb,
  96                                 const struct net_device *in,
  97                                 const struct net_device *out,
  98                                 int (*okfn)(struct sk_buff *))
  99 {
 100         struct nf_conn *ct;
 101         enum ip_conntrack_info ctinfo;
 102         const struct nf_conn_help *help;
 103         const struct nf_conntrack_helper *helper;
 104
 105         /* This is where we call the helper: as the packet goes out. */
 106         ct = nf_ct_get(skb, &ctinfo);
 107         if (!ct || ctinfo == IP_CT_RELATED_REPLY)
 108                 return NF_ACCEPT;
 109
 110         help = nfct_help(ct);
 111         if (!help)
 112                 return NF_ACCEPT;
 113
 114         /* rcu_read_lock()ed by nf_hook_slow */
 115         helper = rcu_dereference(help->helper);
 116         if (!helper)
 117                 return NF_ACCEPT;
 118
 119         return helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
 120                             ct, ctinfo);
 121 }
 122
 123 static unsigned int ipv4_confirm(unsigned int hooknum,
 124                                  struct sk_buff *skb,
 125                                  const struct net_device *in,
 126                                  const struct net_device *out,
 127                                  int (*okfn)(struct sk_buff *))
 128 {
 129         struct nf_conn *ct;
 130         enum ip_conntrack_info ctinfo;
 131
 132         ct = nf_ct_get(skb, &ctinfo);
 133         if (!ct || ctinfo == IP_CT_RELATED_REPLY)
 134                 goto out;
 135
 136         /* adjust seqs for loopback traffic only in outgoing direction */
 137         if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
 138             !nf_is_loopback_packet(skb)) {
 139                 typeof(nf_nat_seq_adjust_hook) seq_adjust;
 140
 141                 seq_adjust = rcu_dereference(nf_nat_seq_adjust_hook);
 142                 if (!seq_adjust ||
 143                     !seq_adjust(skb, ct, ctinfo, ip_hdrlen(skb))) {
 144                         NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
 145                         return NF_DROP;
 146                 }
 147         }
 148 out:
 149         /* We've seen it coming out the other side: confirm it */
 150         return nf_conntrack_confirm(skb);
 151 }
 152
 153 static unsigned int ipv4_conntrack_in(unsigned int hooknum,
 154                                       struct sk_buff *skb,
 155                                       const struct net_device *in,
 156                                       const struct net_device *out,
 157                                       int (*okfn)(struct sk_buff *))
 158 {
 159         return nf_conntrack_in(dev_net(in), PF_INET, hooknum, skb);
 160 }
 161
 162 static unsigned int ipv4_conntrack_local(unsigned int hooknum,
 163                                          struct sk_buff *skb,
 164                                          const struct net_device *in,
 165                                          const struct net_device *out,
 166                                          int (*okfn)(struct sk_buff *))
 167 {
 168         /* root is playing with raw sockets. */
 169         if (skb->len < sizeof(struct iphdr) ||
 170             ip_hdrlen(skb) < sizeof(struct iphdr))
 171                 return NF_ACCEPT;
 172         return nf_conntrack_in(dev_net(out), PF_INET, hooknum, skb);
 173 }
 174
 175 /* Connection tracking may drop packets, but never alters them, so
 176    make it the first hook. */
 177 static struct nf_hook_ops ipv4_conntrack_ops[] __read_mostly = {
 178         {
 179                 .hook           = ipv4_conntrack_in,
 180                 .owner          = THIS_MODULE,
 181                 .pf             = NFPROTO_IPV4,
 182                 .hooknum        = NF_INET_PRE_ROUTING,
 183                 .priority       = NF_IP_PRI_CONNTRACK,
 184         },
 185         {
 186                 .hook           = ipv4_conntrack_local,
 187                 .owner          = THIS_MODULE,
 188                 .pf             = NFPROTO_IPV4,
 189                 .hooknum        = NF_INET_LOCAL_OUT,
 190                 .priority       = NF_IP_PRI_CONNTRACK,
 191         },
 192         {
 193                 .hook           = ipv4_helper,
 194                 .owner          = THIS_MODULE,
 195                 .pf             = NFPROTO_IPV4,
 196                 .hooknum        = NF_INET_POST_ROUTING,
 197                 .priority       = NF_IP_PRI_CONNTRACK_HELPER,
 198         },
 199         {
 200                 .hook           = ipv4_confirm,
 201                 .owner          = THIS_MODULE,
 202                 .pf             = NFPROTO_IPV4,
 203                 .hooknum        = NF_INET_POST_ROUTING,
 204                 .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
 205         },
 206         {
 207                 .hook           = ipv4_helper,
 208                 .owner          = THIS_MODULE,
 209                 .pf             = NFPROTO_IPV4,
 210                 .hooknum        = NF_INET_LOCAL_IN,
 211                 .priority       = NF_IP_PRI_CONNTRACK_HELPER,
 212         },
 213         {
 214                 .hook           = ipv4_confirm,
 215                 .owner          = THIS_MODULE,
 216                 .pf             = NFPROTO_IPV4,
 217                 .hooknum        = NF_INET_LOCAL_IN,
 218                 .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
 219         },
 220 };
 221
 222 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 223 static int log_invalid_proto_min = 0;
 224 static int log_invalid_proto_max = 255;
 225
 226 static struct ctl_table ip_ct_sysctl_table[] = {
 227         {
 228                 .procname       = "ip_conntrack_max",
 229                 .maxlen         = sizeof(int),
 230                 .mode           = 0644,
 231                 .proc_handler   = proc_dointvec,
 232         },
 233         {
 234                 .procname       = "ip_conntrack_count",
 235                 .maxlen         = sizeof(int),
 236                 .mode           = 0444,
 237                 .proc_handler   = proc_dointvec,
 238         },
 239         {
 240                 .procname       = "ip_conntrack_buckets",
 241                 .maxlen         = sizeof(unsigned int),
 242                 .mode           = 0444,
 243                 .proc_handler   = proc_dointvec,
 244         },
 245         {
 246                 .procname       = "ip_conntrack_checksum",
 247                 .maxlen         = sizeof(int),
 248                 .mode           = 0644,
 249                 .proc_handler   = proc_dointvec,
 250         },
 251         {
 252                 .procname       = "ip_conntrack_log_invalid",
 253                 .maxlen         = sizeof(unsigned int),
 254                 .mode           = 0644,
 255                 .proc_handler   = proc_dointvec_minmax,
 256                 .extra1         = &log_invalid_proto_min,
 257                 .extra2         = &log_invalid_proto_max,
 258         },
 259         { }
 260 };
 261 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
 262
 263 /* Fast function for those who don't want to parse /proc (and I don't
 264    blame them). */
 265 /* Reversing the socket's dst/src point of view gives us the reply
 266    mapping. */
 267 static int
 268 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
 269 {
 270         const struct inet_sock *inet = inet_sk(sk);
 271         const struct nf_conntrack_tuple_hash *h;
 272         struct nf_conntrack_tuple tuple;
 273
 274         memset(&tuple, 0, sizeof(tuple));
 275         tuple.src.u3.ip = inet->inet_rcv_saddr;
 276         tuple.src.u.tcp.port = inet->inet_sport;
 277         tuple.dst.u3.ip = inet->inet_daddr;
 278         tuple.dst.u.tcp.port = inet->inet_dport;
 279         tuple.src.l3num = PF_INET;
 280         tuple.dst.protonum = sk->sk_protocol;
 281
 282         /* We only do TCP and SCTP at the moment: is there a better way? */
 283         if (sk->sk_protocol != IPPROTO_TCP && sk->sk_protocol != IPPROTO_SCTP) {
 284                 pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n");
 285                 return -ENOPROTOOPT;
 286         }
 287
 288         if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
 289                 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
 290                          *len, sizeof(struct sockaddr_in));
 291                 return -EINVAL;
 292         }
 293
 294         h = nf_conntrack_find_get(sock_net(sk), NF_CT_DEFAULT_ZONE, &tuple);
 295         if (h) {
 296                 struct sockaddr_in sin;
 297                 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 298
 299                 sin.sin_family = AF_INET;
 300                 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
 301                         .tuple.dst.u.tcp.port;
 302                 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
 303                         .tuple.dst.u3.ip;
 304                 memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
 305
 306                 pr_debug("SO_ORIGINAL_DST: %pI4 %u\n",
 307                          &sin.sin_addr.s_addr, ntohs(sin.sin_port));
 308                 nf_ct_put(ct);
 309                 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
 310                         return -EFAULT;
 311                 else
 312                         return 0;
 313         }
 314         pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n",
 315                  &tuple.src.u3.ip, ntohs(tuple.src.u.tcp.port),
 316                  &tuple.dst.u3.ip, ntohs(tuple.dst.u.tcp.port));
 317         return -ENOENT;
 318 }
 319
 320 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 321
 322 #include <linux/netfilter/nfnetlink.h>
 323 #include <linux/netfilter/nfnetlink_conntrack.h>
 324
 325 static int ipv4_tuple_to_nlattr(struct sk_buff *skb,
 326                                 const struct nf_conntrack_tuple *tuple)
 327 {
 328         if (nla_put_be32(skb, CTA_IP_V4_SRC, tuple->src.u3.ip) ||
 329             nla_put_be32(skb, CTA_IP_V4_DST, tuple->dst.u3.ip))
 330                 goto nla_put_failure;
 331         return 0;
 332
 333 nla_put_failure:
 334         return -1;
 335 }
 336
 337 static const struct nla_policy ipv4_nla_policy[CTA_IP_MAX+1] = {
 338         [CTA_IP_V4_SRC] = { .type = NLA_U32 },
 339         [CTA_IP_V4_DST] = { .type = NLA_U32 },
 340 };
 341
 342 static int ipv4_nlattr_to_tuple(struct nlattr *tb[],
 343                                 struct nf_conntrack_tuple *t)
 344 {
 345         if (!tb[CTA_IP_V4_SRC] || !tb[CTA_IP_V4_DST])
 346                 return -EINVAL;
 347
 348         t->src.u3.ip = nla_get_be32(tb[CTA_IP_V4_SRC]);
 349         t->dst.u3.ip = nla_get_be32(tb[CTA_IP_V4_DST]);
 350
 351         return 0;
 352 }
 353
 354 static int ipv4_nlattr_tuple_size(void)
 355 {
 356         return nla_policy_len(ipv4_nla_policy, CTA_IP_MAX + 1);
 357 }
 358 #endif
 359
 360 static struct nf_sockopt_ops so_getorigdst = {
 361         .pf             = PF_INET,
 362         .get_optmin     = SO_ORIGINAL_DST,
 363         .get_optmax     = SO_ORIGINAL_DST+1,
 364         .get            = &getorigdst,
 365         .owner          = THIS_MODULE,
 366 };
 367
 368 static int ipv4_init_net(struct net *net)
 369 {
 370 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 371         struct nf_ip_net *in = &net->ct.nf_ct_proto;
 372         in->ctl_table = kmemdup(ip_ct_sysctl_table,
 373                                 sizeof(ip_ct_sysctl_table),
 374                                 GFP_KERNEL);
 375         if (!in->ctl_table)
 376                 return -ENOMEM;
 377
 378         in->ctl_table[0].data = &nf_conntrack_max;
 379         in->ctl_table[1].data = &net->ct.count;
 380         in->ctl_table[2].data = &net->ct.htable_size;
 381         in->ctl_table[3].data = &net->ct.sysctl_checksum;
 382         in->ctl_table[4].data = &net->ct.sysctl_log_invalid;
 383 #endif
 384         return 0;
 385 }
 386
 387 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly = {
 388         .l3proto         = PF_INET,
 389         .name            = "ipv4",
 390         .pkt_to_tuple    = ipv4_pkt_to_tuple,
 391         .invert_tuple    = ipv4_invert_tuple,
 392         .print_tuple     = ipv4_print_tuple,
 393         .get_l4proto     = ipv4_get_l4proto,
 394 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 395         .tuple_to_nlattr = ipv4_tuple_to_nlattr,
 396         .nlattr_tuple_size = ipv4_nlattr_tuple_size,
 397         .nlattr_to_tuple = ipv4_nlattr_to_tuple,
 398         .nla_policy      = ipv4_nla_policy,
 399 #endif
 400 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 401         .ctl_table_path  = "net/ipv4/netfilter",
 402 #endif
 403         .init_net        = ipv4_init_net,
 404         .me              = THIS_MODULE,
 405 };
 406
 407 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
 408                   &nf_conntrack_htable_size, 0600);
 409
 410 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
 411 MODULE_ALIAS("ip_conntrack");
 412 MODULE_LICENSE("GPL");
 413
 414 static int ipv4_net_init(struct net *net)
 415 {
 416         int ret = 0;
 417
 418         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_tcp4);
 419         if (ret < 0) {
 420                 pr_err("nf_conntrack_tcp4: pernet registration failed\n");
 421                 goto out_tcp;
 422         }
 423         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udp4);
 424         if (ret < 0) {
 425                 pr_err("nf_conntrack_udp4: pernet registration failed\n");
 426                 goto out_udp;
 427         }
 428         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_icmp);
 429         if (ret < 0) {
 430                 pr_err("nf_conntrack_icmp4: pernet registration failed\n");
 431                 goto out_icmp;
 432         }
 433         ret = nf_ct_l3proto_pernet_register(net, &nf_conntrack_l3proto_ipv4);
 434         if (ret < 0) {
 435                 pr_err("nf_conntrack_ipv4: pernet registration failed\n");
 436                 goto out_ipv4;
 437         }
 438         return 0;
 439 out_ipv4:
 440         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmp);
 441 out_icmp:
 442         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp4);
 443 out_udp:
 444         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp4);
 445 out_tcp:
 446         return ret;
 447 }
 448
 449 static void ipv4_net_exit(struct net *net)
 450 {
 451         nf_ct_l3proto_pernet_unregister(net, &nf_conntrack_l3proto_ipv4);
 452         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmp);
 453         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp4);
 454         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp4);
 455 }
 456
 457 static struct pernet_operations ipv4_net_ops = {
 458         .init = ipv4_net_init,
 459         .exit = ipv4_net_exit,
 460 };
 461
 462 static int __init nf_conntrack_l3proto_ipv4_init(void)
 463 {
 464         int ret = 0;
 465
 466         need_conntrack();
 467         nf_defrag_ipv4_enable();
 468
 469         ret = nf_register_sockopt(&so_getorigdst);
 470         if (ret < 0) {
 471                 printk(KERN_ERR "Unable to register netfilter socket option\n");
 472                 return ret;
 473         }
 474
 475         ret = register_pernet_subsys(&ipv4_net_ops);
 476         if (ret < 0) {
 477                 pr_err("nf_conntrack_ipv4: can't register pernet ops\n");
 478                 goto cleanup_sockopt;
 479         }
 480
 481         ret = nf_register_hooks(ipv4_conntrack_ops,
 482                                 ARRAY_SIZE(ipv4_conntrack_ops));
 483         if (ret < 0) {
 484                 pr_err("nf_conntrack_ipv4: can't register hooks.\n");
 485                 goto cleanup_pernet;
 486         }
 487
 488         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_tcp4);
 489         if (ret < 0) {
 490                 pr_err("nf_conntrack_ipv4: can't register tcp4 proto.\n");
 491                 goto cleanup_hooks;
 492         }
 493
 494         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udp4);
 495         if (ret < 0) {
 496                 pr_err("nf_conntrack_ipv4: can't register udp4 proto.\n");
 497                 goto cleanup_tcp4;
 498         }
 499
 500         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_icmp);
 501         if (ret < 0) {
 502                 pr_err("nf_conntrack_ipv4: can't register icmpv4 proto.\n");
 503                 goto cleanup_udp4;
 504         }
 505
 506         ret = nf_ct_l3proto_register(&nf_conntrack_l3proto_ipv4);
 507         if (ret < 0) {
 508                 pr_err("nf_conntrack_ipv4: can't register ipv4 proto.\n");
 509                 goto cleanup_icmpv4;
 510         }
 511
 512 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 513         ret = nf_conntrack_ipv4_compat_init();
 514         if (ret < 0)
 515                 goto cleanup_proto;
 516 #endif
 517         return ret;
 518 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 519  cleanup_proto:
 520         nf_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
 521 #endif
 522  cleanup_icmpv4:
 523         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmp);
 524  cleanup_udp4:
 525         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp4);
 526  cleanup_tcp4:
 527         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
 528  cleanup_hooks:
 529         nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
 530  cleanup_pernet:
 531         unregister_pernet_subsys(&ipv4_net_ops);
 532  cleanup_sockopt:
 533         nf_unregister_sockopt(&so_getorigdst);
 534         return ret;
 535 }
 536
 537 static void __exit nf_conntrack_l3proto_ipv4_fini(void)
 538 {
 539         synchronize_net();
 540 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
 541         nf_conntrack_ipv4_compat_fini();
 542 #endif
 543         nf_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
 544         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmp);
 545         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp4);
 546         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
 547         nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
 548         unregister_pernet_subsys(&ipv4_net_ops);
 549         nf_unregister_sockopt(&so_getorigdst);
 550 }
 551
 552 module_init(nf_conntrack_l3proto_ipv4_init);
 553 module_exit(nf_conntrack_l3proto_ipv4_fini);
 554
 555 void need_ipv4_conntrack(void)
 556 {
 557         return;
 558 }
 559 EXPORT_SYMBOL_GPL(need_ipv4_conntrack);