net/netfilter/xt_TPROXY.c

   1 /*
   2  * Transparent proxy support for Linux/iptables
   3  *
   4  * Copyright (c) 2006-2010 BalaBit IT Ltd.
   5  * Author: Balazs Scheidler, Krisztian Kovacs
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  */
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13 #include <linux/module.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/ip.h>
  16 #include <net/checksum.h>
  17 #include <net/udp.h>
  18 #include <net/tcp.h>
  19 #include <net/inet_sock.h>
  20 #include <net/inet_hashtables.h>
  21 #include <linux/inetdevice.h>
  22 #include <linux/netfilter/x_tables.h>
  23 #include <linux/netfilter_ipv4/ip_tables.h>
  24
  25 #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
  26
  27 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
  28 #define XT_TPROXY_HAVE_IPV6 1
  29 #include <net/if_inet6.h>
  30 #include <net/addrconf.h>
  31 #include <net/inet6_hashtables.h>
  32 #include <linux/netfilter_ipv6/ip6_tables.h>
  33 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
  34 #endif
  35
  36 #include <linux/netfilter/xt_TPROXY.h>
  37
  38 enum nf_tproxy_lookup_t {
  39          NFT_LOOKUP_LISTENER,
  40          NFT_LOOKUP_ESTABLISHED,
  41 };
  42
  43 static bool tproxy_sk_is_transparent(struct sock *sk)
  44 {
  45         switch (sk->sk_state) {
  46         case TCP_TIME_WAIT:
  47                 if (inet_twsk(sk)->tw_transparent)
  48                         return true;
  49                 break;
  50         case TCP_NEW_SYN_RECV:
  51                 if (inet_rsk(inet_reqsk(sk))->no_srccheck)
  52                         return true;
  53                 break;
  54         default:
  55                 if (inet_sk(sk)->transparent)
  56                         return true;
  57         }
  58
  59         sock_gen_put(sk);
  60         return false;
  61 }
  62
  63 static inline __be32
  64 tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr)
  65 {
  66         struct in_device *indev;
  67         __be32 laddr;
  68
  69         if (user_laddr)
  70                 return user_laddr;
  71
  72         laddr = 0;
  73         rcu_read_lock();
  74         indev = __in_dev_get_rcu(skb->dev);
  75         for_primary_ifa(indev) {
  76                 laddr = ifa->ifa_local;
  77                 break;
  78         } endfor_ifa(indev);
  79         rcu_read_unlock();
  80
  81         return laddr ? laddr : daddr;
  82 }
  83
  84 /*
  85  * This is used when the user wants to intercept a connection matching
  86  * an explicit iptables rule. In this case the sockets are assumed
  87  * matching in preference order:
  88  *
  89  *   - match: if there's a fully established connection matching the
  90  *     _packet_ tuple, it is returned, assuming the redirection
  91  *     already took place and we process a packet belonging to an
  92  *     established connection
  93  *
  94  *   - match: if there's a listening socket matching the redirection
  95  *     (e.g. on-port & on-ip of the connection), it is returned,
  96  *     regardless if it was bound to 0.0.0.0 or an explicit
  97  *     address. The reasoning is that if there's an explicit rule, it
  98  *     does not really matter if the listener is bound to an interface
  99  *     or to 0. The user already stated that he wants redirection
 100  *     (since he added the rule).
 101  *
 102  * Please note that there's an overlap between what a TPROXY target
 103  * and a socket match will match. Normally if you have both rules the
 104  * "socket" match will be the first one, effectively all packets
 105  * belonging to established connections going through that one.
 106  */
 107 static inline struct sock *
 108 nf_tproxy_get_sock_v4(struct net *net, const u8 protocol,
 109                       const __be32 saddr, const __be32 daddr,
 110                       const __be16 sport, const __be16 dport,
 111                       const struct net_device *in,
 112                       const enum nf_tproxy_lookup_t lookup_type)
 113 {
 114         struct sock *sk;
 115
 116         switch (protocol) {
 117         case IPPROTO_TCP:
 118                 switch (lookup_type) {
 119                 case NFT_LOOKUP_LISTENER:
 120                         sk = inet_lookup_listener(net, &tcp_hashinfo,
 121                                                     saddr, sport,
 122                                                     daddr, dport,
 123                                                     in->ifindex);
 124
 125                         /* NOTE: we return listeners even if bound to
 126                          * 0.0.0.0, those are filtered out in
 127                          * xt_socket, since xt_TPROXY needs 0 bound
 128                          * listeners too
 129                          */
 130                         break;
 131                 case NFT_LOOKUP_ESTABLISHED:
 132                         sk = inet_lookup_established(net, &tcp_hashinfo,
 133                                                     saddr, sport, daddr, dport,
 134                                                     in->ifindex);
 135                         break;
 136                 default:
 137                         BUG();
 138                 }
 139                 break;
 140         case IPPROTO_UDP:
 141                 sk = udp4_lib_lookup(net, saddr, sport, daddr, dport,
 142                                      in->ifindex);
 143                 if (sk) {
 144                         int connected = (sk->sk_state == TCP_ESTABLISHED);
 145                         int wildcard = (inet_sk(sk)->inet_rcv_saddr == 0);
 146
 147                         /* NOTE: we return listeners even if bound to
 148                          * 0.0.0.0, those are filtered out in
 149                          * xt_socket, since xt_TPROXY needs 0 bound
 150                          * listeners too
 151                          */
 152                         if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
 153                             (lookup_type == NFT_LOOKUP_LISTENER && connected)) {
 154                                 sock_put(sk);
 155                                 sk = NULL;
 156                         }
 157                 }
 158                 break;
 159         default:
 160                 WARN_ON(1);
 161                 sk = NULL;
 162         }
 163
 164         pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, lookup type: %d, sock %p\n",
 165                  protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), lookup_type, sk);
 166
 167         return sk;
 168 }
 169
 170 #ifdef XT_TPROXY_HAVE_IPV6
 171 static inline struct sock *
 172 nf_tproxy_get_sock_v6(struct net *net, const u8 protocol,
 173                       const struct in6_addr *saddr, const struct in6_addr *daddr,
 174                       const __be16 sport, const __be16 dport,
 175                       const struct net_device *in,
 176                       const enum nf_tproxy_lookup_t lookup_type)
 177 {
 178         struct sock *sk;
 179
 180         switch (protocol) {
 181         case IPPROTO_TCP:
 182                 switch (lookup_type) {
 183                 case NFT_LOOKUP_LISTENER:
 184                         sk = inet6_lookup_listener(net, &tcp_hashinfo,
 185                                                    saddr, sport,
 186                                                    daddr, ntohs(dport),
 187                                                    in->ifindex);
 188
 189                         /* NOTE: we return listeners even if bound to
 190                          * 0.0.0.0, those are filtered out in
 191                          * xt_socket, since xt_TPROXY needs 0 bound
 192                          * listeners too
 193                          */
 194                         break;
 195                 case NFT_LOOKUP_ESTABLISHED:
 196                         sk = __inet6_lookup_established(net, &tcp_hashinfo,
 197                                                         saddr, sport, daddr, ntohs(dport),
 198                                                         in->ifindex);
 199                         break;
 200                 default:
 201                         BUG();
 202                 }
 203                 break;
 204         case IPPROTO_UDP:
 205                 sk = udp6_lib_lookup(net, saddr, sport, daddr, dport,
 206                                      in->ifindex);
 207                 if (sk) {
 208                         int connected = (sk->sk_state == TCP_ESTABLISHED);
 209                         int wildcard = ipv6_addr_any(&sk->sk_v6_rcv_saddr);
 210
 211                         /* NOTE: we return listeners even if bound to
 212                          * 0.0.0.0, those are filtered out in
 213                          * xt_socket, since xt_TPROXY needs 0 bound
 214                          * listeners too
 215                          */
 216                         if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
 217                             (lookup_type == NFT_LOOKUP_LISTENER && connected)) {
 218                                 sock_put(sk);
 219                                 sk = NULL;
 220                         }
 221                 }
 222                 break;
 223         default:
 224                 WARN_ON(1);
 225                 sk = NULL;
 226         }
 227
 228         pr_debug("tproxy socket lookup: proto %u %pI6:%u -> %pI6:%u, lookup type: %d, sock %p\n",
 229                  protocol, saddr, ntohs(sport), daddr, ntohs(dport), lookup_type, sk);
 230
 231         return sk;
 232 }
 233 #endif
 234
 235 /**
 236  * tproxy_handle_time_wait4 - handle IPv4 TCP TIME_WAIT reopen redirections
 237  * @skb:        The skb being processed.
 238  * @laddr:      IPv4 address to redirect to or zero.
 239  * @lport:      TCP port to redirect to or zero.
 240  * @sk:         The TIME_WAIT TCP socket found by the lookup.
 241  *
 242  * We have to handle SYN packets arriving to TIME_WAIT sockets
 243  * differently: instead of reopening the connection we should rather
 244  * redirect the new connection to the proxy if there's a listener
 245  * socket present.
 246  *
 247  * tproxy_handle_time_wait4() consumes the socket reference passed in.
 248  *
 249  * Returns the listener socket if there's one, the TIME_WAIT socket if
 250  * no such listener is found, or NULL if the TCP header is incomplete.
 251  */
 252 static struct sock *
 253 tproxy_handle_time_wait4(struct net *net, struct sk_buff *skb,
 254                          __be32 laddr, __be16 lport, struct sock *sk)
 255 {
 256         const struct iphdr *iph = ip_hdr(skb);
 257         struct tcphdr _hdr, *hp;
 258
 259         hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
 260         if (hp == NULL) {
 261                 inet_twsk_put(inet_twsk(sk));
 262                 return NULL;
 263         }
 264
 265         if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
 266                 /* SYN to a TIME_WAIT socket, we'd rather redirect it
 267                  * to a listener socket if there's one */
 268                 struct sock *sk2;
 269
 270                 sk2 = nf_tproxy_get_sock_v4(net, iph->protocol,
 271                                             iph->saddr, laddr ? laddr : iph->daddr,
 272                                             hp->source, lport ? lport : hp->dest,
 273                                             skb->dev, NFT_LOOKUP_LISTENER);
 274                 if (sk2) {
 275                         inet_twsk_deschedule_put(inet_twsk(sk));
 276                         sk = sk2;
 277                 }
 278         }
 279
 280         return sk;
 281 }
 282
 283 /* assign a socket to the skb -- consumes sk */
 284 static void
 285 nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk)
 286 {
 287         skb_orphan(skb);
 288         skb->sk = sk;
 289         skb->destructor = sock_edemux;
 290 }
 291
 292 static unsigned int
 293 tproxy_tg4(struct net *net, struct sk_buff *skb, __be32 laddr, __be16 lport,
 294            u_int32_t mark_mask, u_int32_t mark_value)
 295 {
 296         const struct iphdr *iph = ip_hdr(skb);
 297         struct udphdr _hdr, *hp;
 298         struct sock *sk;
 299
 300         hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
 301         if (hp == NULL)
 302                 return NF_DROP;
 303
 304         /* check if there's an ongoing connection on the packet
 305          * addresses, this happens if the redirect already happened
 306          * and the current packet belongs to an already established
 307          * connection */
 308         sk = nf_tproxy_get_sock_v4(net, iph->protocol,
 309                                    iph->saddr, iph->daddr,
 310                                    hp->source, hp->dest,
 311                                    skb->dev, NFT_LOOKUP_ESTABLISHED);
 312
 313         laddr = tproxy_laddr4(skb, laddr, iph->daddr);
 314         if (!lport)
 315                 lport = hp->dest;
 316
 317         /* UDP has no TCP_TIME_WAIT state, so we never enter here */
 318         if (sk && sk->sk_state == TCP_TIME_WAIT)
 319                 /* reopening a TIME_WAIT connection needs special handling */
 320                 sk = tproxy_handle_time_wait4(net, skb, laddr, lport, sk);
 321         else if (!sk)
 322                 /* no, there's no established connection, check if
 323                  * there's a listener on the redirected addr/port */
 324                 sk = nf_tproxy_get_sock_v4(net, iph->protocol,
 325                                            iph->saddr, laddr,
 326                                            hp->source, lport,
 327                                            skb->dev, NFT_LOOKUP_LISTENER);
 328
 329         /* NOTE: assign_sock consumes our sk reference */
 330         if (sk && tproxy_sk_is_transparent(sk)) {
 331                 /* This should be in a separate target, but we don't do multiple
 332                    targets on the same rule yet */
 333                 skb->mark = (skb->mark & ~mark_mask) ^ mark_value;
 334
 335                 pr_debug("redirecting: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
 336                          iph->protocol, &iph->daddr, ntohs(hp->dest),
 337                          &laddr, ntohs(lport), skb->mark);
 338
 339                 nf_tproxy_assign_sock(skb, sk);
 340                 return NF_ACCEPT;
 341         }
 342
 343         pr_debug("no socket, dropping: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
 344                  iph->protocol, &iph->saddr, ntohs(hp->source),
 345                  &iph->daddr, ntohs(hp->dest), skb->mark);
 346         return NF_DROP;
 347 }
 348
 349 static unsigned int
 350 tproxy_tg4_v0(struct sk_buff *skb, const struct xt_action_param *par)
 351 {
 352         const struct xt_tproxy_target_info *tgi = par->targinfo;
 353
 354         return tproxy_tg4(par->net, skb, tgi->laddr, tgi->lport, tgi->mark_mask, tgi->mark_value);
 355 }
 356
 357 static unsigned int
 358 tproxy_tg4_v1(struct sk_buff *skb, const struct xt_action_param *par)
 359 {
 360         const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
 361
 362         return tproxy_tg4(par->net, skb, tgi->laddr.ip, tgi->lport, tgi->mark_mask, tgi->mark_value);
 363 }
 364
 365 #ifdef XT_TPROXY_HAVE_IPV6
 366
 367 static inline const struct in6_addr *
 368 tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr,
 369               const struct in6_addr *daddr)
 370 {
 371         struct inet6_dev *indev;
 372         struct inet6_ifaddr *ifa;
 373         struct in6_addr *laddr;
 374
 375         if (!ipv6_addr_any(user_laddr))
 376                 return user_laddr;
 377         laddr = NULL;
 378
 379         rcu_read_lock();
 380         indev = __in6_dev_get(skb->dev);
 381         if (indev)
 382                 list_for_each_entry(ifa, &indev->addr_list, if_list) {
 383                         if (ifa->flags & (IFA_F_TENTATIVE | IFA_F_DEPRECATED))
 384                                 continue;
 385
 386                         laddr = &ifa->addr;
 387                         break;
 388                 }
 389         rcu_read_unlock();
 390
 391         return laddr ? laddr : daddr;
 392 }
 393
 394 /**
 395  * tproxy_handle_time_wait6 - handle IPv6 TCP TIME_WAIT reopen redirections
 396  * @skb:        The skb being processed.
 397  * @tproto:     Transport protocol.
 398  * @thoff:      Transport protocol header offset.
 399  * @par:        Iptables target parameters.
 400  * @sk:         The TIME_WAIT TCP socket found by the lookup.
 401  *
 402  * We have to handle SYN packets arriving to TIME_WAIT sockets
 403  * differently: instead of reopening the connection we should rather
 404  * redirect the new connection to the proxy if there's a listener
 405  * socket present.
 406  *
 407  * tproxy_handle_time_wait6() consumes the socket reference passed in.
 408  *
 409  * Returns the listener socket if there's one, the TIME_WAIT socket if
 410  * no such listener is found, or NULL if the TCP header is incomplete.
 411  */
 412 static struct sock *
 413 tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
 414                          const struct xt_action_param *par,
 415                          struct sock *sk)
 416 {
 417         const struct ipv6hdr *iph = ipv6_hdr(skb);
 418         struct tcphdr _hdr, *hp;
 419         const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
 420
 421         hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
 422         if (hp == NULL) {
 423                 inet_twsk_put(inet_twsk(sk));
 424                 return NULL;
 425         }
 426
 427         if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
 428                 /* SYN to a TIME_WAIT socket, we'd rather redirect it
 429                  * to a listener socket if there's one */
 430                 struct sock *sk2;
 431
 432                 sk2 = nf_tproxy_get_sock_v6(par->net, tproto,
 433                                             &iph->saddr,
 434                                             tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr),
 435                                             hp->source,
 436                                             tgi->lport ? tgi->lport : hp->dest,
 437                                             skb->dev, NFT_LOOKUP_LISTENER);
 438                 if (sk2) {
 439                         inet_twsk_deschedule_put(inet_twsk(sk));
 440                         sk = sk2;
 441                 }
 442         }
 443
 444         return sk;
 445 }
 446
 447 static unsigned int
 448 tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
 449 {
 450         const struct ipv6hdr *iph = ipv6_hdr(skb);
 451         const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
 452         struct udphdr _hdr, *hp;
 453         struct sock *sk;
 454         const struct in6_addr *laddr;
 455         __be16 lport;
 456         int thoff = 0;
 457         int tproto;
 458
 459         tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL);
 460         if (tproto < 0) {
 461                 pr_debug("unable to find transport header in IPv6 packet, dropping\n");
 462                 return NF_DROP;
 463         }
 464
 465         hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
 466         if (hp == NULL) {
 467                 pr_debug("unable to grab transport header contents in IPv6 packet, dropping\n");
 468                 return NF_DROP;
 469         }
 470
 471         /* check if there's an ongoing connection on the packet
 472          * addresses, this happens if the redirect already happened
 473          * and the current packet belongs to an already established
 474          * connection */
 475         sk = nf_tproxy_get_sock_v6(par->net, tproto,
 476                                    &iph->saddr, &iph->daddr,
 477                                    hp->source, hp->dest,
 478                                    par->in, NFT_LOOKUP_ESTABLISHED);
 479
 480         laddr = tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr);
 481         lport = tgi->lport ? tgi->lport : hp->dest;
 482
 483         /* UDP has no TCP_TIME_WAIT state, so we never enter here */
 484         if (sk && sk->sk_state == TCP_TIME_WAIT)
 485                 /* reopening a TIME_WAIT connection needs special handling */
 486                 sk = tproxy_handle_time_wait6(skb, tproto, thoff, par, sk);
 487         else if (!sk)
 488                 /* no there's no established connection, check if
 489                  * there's a listener on the redirected addr/port */
 490                 sk = nf_tproxy_get_sock_v6(par->net, tproto,
 491                                            &iph->saddr, laddr,
 492                                            hp->source, lport,
 493                                            par->in, NFT_LOOKUP_LISTENER);
 494
 495         /* NOTE: assign_sock consumes our sk reference */
 496         if (sk && tproxy_sk_is_transparent(sk)) {
 497                 /* This should be in a separate target, but we don't do multiple
 498                    targets on the same rule yet */
 499                 skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;
 500
 501                 pr_debug("redirecting: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
 502                          tproto, &iph->saddr, ntohs(hp->source),
 503                          laddr, ntohs(lport), skb->mark);
 504
 505                 nf_tproxy_assign_sock(skb, sk);
 506                 return NF_ACCEPT;
 507         }
 508
 509         pr_debug("no socket, dropping: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
 510                  tproto, &iph->saddr, ntohs(hp->source),
 511                  &iph->daddr, ntohs(hp->dest), skb->mark);
 512
 513         return NF_DROP;
 514 }
 515
 516 static int tproxy_tg6_check(const struct xt_tgchk_param *par)
 517 {
 518         const struct ip6t_ip6 *i = par->entryinfo;
 519
 520         if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP) &&
 521             !(i->invflags & IP6T_INV_PROTO))
 522                 return 0;
 523
 524         pr_info("Can be used only in combination with "
 525                 "either -p tcp or -p udp\n");
 526         return -EINVAL;
 527 }
 528 #endif
 529
 530 static int tproxy_tg4_check(const struct xt_tgchk_param *par)
 531 {
 532         const struct ipt_ip *i = par->entryinfo;
 533
 534         if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP)
 535             && !(i->invflags & IPT_INV_PROTO))
 536                 return 0;
 537
 538         pr_info("Can be used only in combination with "
 539                 "either -p tcp or -p udp\n");
 540         return -EINVAL;
 541 }
 542
 543 static struct xt_target tproxy_tg_reg[] __read_mostly = {
 544         {
 545                 .name           = "TPROXY",
 546                 .family         = NFPROTO_IPV4,
 547                 .table          = "mangle",
 548                 .target         = tproxy_tg4_v0,
 549                 .revision       = 0,
 550                 .targetsize     = sizeof(struct xt_tproxy_target_info),
 551                 .checkentry     = tproxy_tg4_check,
 552                 .hooks          = 1 << NF_INET_PRE_ROUTING,
 553                 .me             = THIS_MODULE,
 554         },
 555         {
 556                 .name           = "TPROXY",
 557                 .family         = NFPROTO_IPV4,
 558                 .table          = "mangle",
 559                 .target         = tproxy_tg4_v1,
 560                 .revision       = 1,
 561                 .targetsize     = sizeof(struct xt_tproxy_target_info_v1),
 562                 .checkentry     = tproxy_tg4_check,
 563                 .hooks          = 1 << NF_INET_PRE_ROUTING,
 564                 .me             = THIS_MODULE,
 565         },
 566 #ifdef XT_TPROXY_HAVE_IPV6
 567         {
 568                 .name           = "TPROXY",
 569                 .family         = NFPROTO_IPV6,
 570                 .table          = "mangle",
 571                 .target         = tproxy_tg6_v1,
 572                 .revision       = 1,
 573                 .targetsize     = sizeof(struct xt_tproxy_target_info_v1),
 574                 .checkentry     = tproxy_tg6_check,
 575                 .hooks          = 1 << NF_INET_PRE_ROUTING,
 576                 .me             = THIS_MODULE,
 577         },
 578 #endif
 579
 580 };
 581
 582 static int __init tproxy_tg_init(void)
 583 {
 584         nf_defrag_ipv4_enable();
 585 #ifdef XT_TPROXY_HAVE_IPV6
 586         nf_defrag_ipv6_enable();
 587 #endif
 588
 589         return xt_register_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
 590 }
 591
 592 static void __exit tproxy_tg_exit(void)
 593 {
 594         xt_unregister_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
 595 }
 596
 597 module_init(tproxy_tg_init);
 598 module_exit(tproxy_tg_exit);
 599 MODULE_LICENSE("GPL");
 600 MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
 601 MODULE_DESCRIPTION("Netfilter transparent proxy (TPROXY) target module.");
 602 MODULE_ALIAS("ipt_TPROXY");
 603 MODULE_ALIAS("ip6t_TPROXY");