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         if (sk->sk_state != TCP_TIME_WAIT) {
  46                 if (inet_sk(sk)->transparent)
  47                         return true;
  48                 sock_put(sk);
  49         } else {
  50                 if (inet_twsk(sk)->tw_transparent)
  51                         return true;
  52                 inet_twsk_put(inet_twsk(sk));
  53         }
  54         return false;
  55 }
  56
  57 static inline __be32
  58 tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr)
  59 {
  60         struct in_device *indev;
  61         __be32 laddr;
  62
  63         if (user_laddr)
  64                 return user_laddr;
  65
  66         laddr = 0;
  67         rcu_read_lock();
  68         indev = __in_dev_get_rcu(skb->dev);
  69         for_primary_ifa(indev) {
  70                 laddr = ifa->ifa_local;
  71                 break;
  72         } endfor_ifa(indev);
  73         rcu_read_unlock();
  74
  75         return laddr ? laddr : daddr;
  76 }
  77
  78 /*
  79  * This is used when the user wants to intercept a connection matching
  80  * an explicit iptables rule. In this case the sockets are assumed
  81  * matching in preference order:
  82  *
  83  *   - match: if there's a fully established connection matching the
  84  *     _packet_ tuple, it is returned, assuming the redirection
  85  *     already took place and we process a packet belonging to an
  86  *     established connection
  87  *
  88  *   - match: if there's a listening socket matching the redirection
  89  *     (e.g. on-port & on-ip of the connection), it is returned,
  90  *     regardless if it was bound to 0.0.0.0 or an explicit
  91  *     address. The reasoning is that if there's an explicit rule, it
  92  *     does not really matter if the listener is bound to an interface
  93  *     or to 0. The user already stated that he wants redirection
  94  *     (since he added the rule).
  95  *
  96  * Please note that there's an overlap between what a TPROXY target
  97  * and a socket match will match. Normally if you have both rules the
  98  * "socket" match will be the first one, effectively all packets
  99  * belonging to established connections going through that one.
 100  */
 101 static inline struct sock *
 102 nf_tproxy_get_sock_v4(struct net *net, const u8 protocol,
 103                       const __be32 saddr, const __be32 daddr,
 104                       const __be16 sport, const __be16 dport,
 105                       const struct net_device *in,
 106                       const enum nf_tproxy_lookup_t lookup_type)
 107 {
 108         struct sock *sk;
 109
 110         switch (protocol) {
 111         case IPPROTO_TCP:
 112                 switch (lookup_type) {
 113                 case NFT_LOOKUP_LISTENER:
 114                         sk = inet_lookup_listener(net, &tcp_hashinfo,
 115                                                     saddr, sport,
 116                                                     daddr, dport,
 117                                                     in->ifindex);
 118
 119                         /* NOTE: we return listeners even if bound to
 120                          * 0.0.0.0, those are filtered out in
 121                          * xt_socket, since xt_TPROXY needs 0 bound
 122                          * listeners too
 123                          */
 124                         break;
 125                 case NFT_LOOKUP_ESTABLISHED:
 126                         sk = inet_lookup_established(net, &tcp_hashinfo,
 127                                                     saddr, sport, daddr, dport,
 128                                                     in->ifindex);
 129                         break;
 130                 default:
 131                         BUG();
 132                 }
 133                 break;
 134         case IPPROTO_UDP:
 135                 sk = udp4_lib_lookup(net, saddr, sport, daddr, dport,
 136                                      in->ifindex);
 137                 if (sk) {
 138                         int connected = (sk->sk_state == TCP_ESTABLISHED);
 139                         int wildcard = (inet_sk(sk)->inet_rcv_saddr == 0);
 140
 141                         /* NOTE: we return listeners even if bound to
 142                          * 0.0.0.0, those are filtered out in
 143                          * xt_socket, since xt_TPROXY needs 0 bound
 144                          * listeners too
 145                          */
 146                         if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
 147                             (lookup_type == NFT_LOOKUP_LISTENER && connected)) {
 148                                 sock_put(sk);
 149                                 sk = NULL;
 150                         }
 151                 }
 152                 break;
 153         default:
 154                 WARN_ON(1);
 155                 sk = NULL;
 156         }
 157
 158         pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, lookup type: %d, sock %p\n",
 159                  protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), lookup_type, sk);
 160
 161         return sk;
 162 }
 163
 164 #ifdef XT_TPROXY_HAVE_IPV6
 165 static inline struct sock *
 166 nf_tproxy_get_sock_v6(struct net *net, const u8 protocol,
 167                       const struct in6_addr *saddr, const struct in6_addr *daddr,
 168                       const __be16 sport, const __be16 dport,
 169                       const struct net_device *in,
 170                       const enum nf_tproxy_lookup_t lookup_type)
 171 {
 172         struct sock *sk;
 173
 174         switch (protocol) {
 175         case IPPROTO_TCP:
 176                 switch (lookup_type) {
 177                 case NFT_LOOKUP_LISTENER:
 178                         sk = inet6_lookup_listener(net, &tcp_hashinfo,
 179                                                    saddr, sport,
 180                                                    daddr, ntohs(dport),
 181                                                    in->ifindex);
 182
 183                         /* NOTE: we return listeners even if bound to
 184                          * 0.0.0.0, those are filtered out in
 185                          * xt_socket, since xt_TPROXY needs 0 bound
 186                          * listeners too
 187                          */
 188                         break;
 189                 case NFT_LOOKUP_ESTABLISHED:
 190                         sk = __inet6_lookup_established(net, &tcp_hashinfo,
 191                                                         saddr, sport, daddr, ntohs(dport),
 192                                                         in->ifindex);
 193                         break;
 194                 default:
 195                         BUG();
 196                 }
 197                 break;
 198         case IPPROTO_UDP:
 199                 sk = udp6_lib_lookup(net, saddr, sport, daddr, dport,
 200                                      in->ifindex);
 201                 if (sk) {
 202                         int connected = (sk->sk_state == TCP_ESTABLISHED);
 203                         int wildcard = ipv6_addr_any(&inet6_sk(sk)->rcv_saddr);
 204
 205                         /* NOTE: we return listeners even if bound to
 206                          * 0.0.0.0, those are filtered out in
 207                          * xt_socket, since xt_TPROXY needs 0 bound
 208                          * listeners too
 209                          */
 210                         if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
 211                             (lookup_type == NFT_LOOKUP_LISTENER && connected)) {
 212                                 sock_put(sk);
 213                                 sk = NULL;
 214                         }
 215                 }
 216                 break;
 217         default:
 218                 WARN_ON(1);
 219                 sk = NULL;
 220         }
 221
 222         pr_debug("tproxy socket lookup: proto %u %pI6:%u -> %pI6:%u, lookup type: %d, sock %p\n",
 223                  protocol, saddr, ntohs(sport), daddr, ntohs(dport), lookup_type, sk);
 224
 225         return sk;
 226 }
 227 #endif
 228
 229 /**
 230  * tproxy_handle_time_wait4 - handle IPv4 TCP TIME_WAIT reopen redirections
 231  * @skb:        The skb being processed.
 232  * @laddr:      IPv4 address to redirect to or zero.
 233  * @lport:      TCP port to redirect to or zero.
 234  * @sk:         The TIME_WAIT TCP socket found by the lookup.
 235  *
 236  * We have to handle SYN packets arriving to TIME_WAIT sockets
 237  * differently: instead of reopening the connection we should rather
 238  * redirect the new connection to the proxy if there's a listener
 239  * socket present.
 240  *
 241  * tproxy_handle_time_wait4() consumes the socket reference passed in.
 242  *
 243  * Returns the listener socket if there's one, the TIME_WAIT socket if
 244  * no such listener is found, or NULL if the TCP header is incomplete.
 245  */
 246 static struct sock *
 247 tproxy_handle_time_wait4(struct sk_buff *skb, __be32 laddr, __be16 lport,
 248                         struct sock *sk)
 249 {
 250         const struct iphdr *iph = ip_hdr(skb);
 251         struct tcphdr _hdr, *hp;
 252
 253         hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
 254         if (hp == NULL) {
 255                 inet_twsk_put(inet_twsk(sk));
 256                 return NULL;
 257         }
 258
 259         if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
 260                 /* SYN to a TIME_WAIT socket, we'd rather redirect it
 261                  * to a listener socket if there's one */
 262                 struct sock *sk2;
 263
 264                 sk2 = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
 265                                             iph->saddr, laddr ? laddr : iph->daddr,
 266                                             hp->source, lport ? lport : hp->dest,
 267                                             skb->dev, NFT_LOOKUP_LISTENER);
 268                 if (sk2) {
 269                         inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
 270                         inet_twsk_put(inet_twsk(sk));
 271                         sk = sk2;
 272                 }
 273         }
 274
 275         return sk;
 276 }
 277
 278 /* assign a socket to the skb -- consumes sk */
 279 static void
 280 nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk)
 281 {
 282         skb_orphan(skb);
 283         skb->sk = sk;
 284         skb->destructor = sock_edemux;
 285 }
 286
 287 static unsigned int
 288 tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
 289            u_int32_t mark_mask, u_int32_t mark_value)
 290 {
 291         const struct iphdr *iph = ip_hdr(skb);
 292         struct udphdr _hdr, *hp;
 293         struct sock *sk;
 294
 295         hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
 296         if (hp == NULL)
 297                 return NF_DROP;
 298
 299         /* check if there's an ongoing connection on the packet
 300          * addresses, this happens if the redirect already happened
 301          * and the current packet belongs to an already established
 302          * connection */
 303         sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
 304                                    iph->saddr, iph->daddr,
 305                                    hp->source, hp->dest,
 306                                    skb->dev, NFT_LOOKUP_ESTABLISHED);
 307
 308         laddr = tproxy_laddr4(skb, laddr, iph->daddr);
 309         if (!lport)
 310                 lport = hp->dest;
 311
 312         /* UDP has no TCP_TIME_WAIT state, so we never enter here */
 313         if (sk && sk->sk_state == TCP_TIME_WAIT)
 314                 /* reopening a TIME_WAIT connection needs special handling */
 315                 sk = tproxy_handle_time_wait4(skb, laddr, lport, sk);
 316         else if (!sk)
 317                 /* no, there's no established connection, check if
 318                  * there's a listener on the redirected addr/port */
 319                 sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
 320                                            iph->saddr, laddr,
 321                                            hp->source, lport,
 322                                            skb->dev, NFT_LOOKUP_LISTENER);
 323
 324         /* NOTE: assign_sock consumes our sk reference */
 325         if (sk && tproxy_sk_is_transparent(sk)) {
 326                 /* This should be in a separate target, but we don't do multiple
 327                    targets on the same rule yet */
 328                 skb->mark = (skb->mark & ~mark_mask) ^ mark_value;
 329
 330                 pr_debug("redirecting: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
 331                          iph->protocol, &iph->daddr, ntohs(hp->dest),
 332                          &laddr, ntohs(lport), skb->mark);
 333
 334                 nf_tproxy_assign_sock(skb, sk);
 335                 return NF_ACCEPT;
 336         }
 337
 338         pr_debug("no socket, dropping: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
 339                  iph->protocol, &iph->saddr, ntohs(hp->source),
 340                  &iph->daddr, ntohs(hp->dest), skb->mark);
 341         return NF_DROP;
 342 }
 343
 344 static unsigned int
 345 tproxy_tg4_v0(struct sk_buff *skb, const struct xt_action_param *par)
 346 {
 347         const struct xt_tproxy_target_info *tgi = par->targinfo;
 348
 349         return tproxy_tg4(skb, tgi->laddr, tgi->lport, tgi->mark_mask, tgi->mark_value);
 350 }
 351
 352 static unsigned int
 353 tproxy_tg4_v1(struct sk_buff *skb, const struct xt_action_param *par)
 354 {
 355         const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
 356
 357         return tproxy_tg4(skb, tgi->laddr.ip, tgi->lport, tgi->mark_mask, tgi->mark_value);
 358 }
 359
 360 #ifdef XT_TPROXY_HAVE_IPV6
 361
 362 static inline const struct in6_addr *
 363 tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr,
 364               const struct in6_addr *daddr)
 365 {
 366         struct inet6_dev *indev;
 367         struct inet6_ifaddr *ifa;
 368         struct in6_addr *laddr;
 369
 370         if (!ipv6_addr_any(user_laddr))
 371                 return user_laddr;
 372         laddr = NULL;
 373
 374         rcu_read_lock();
 375         indev = __in6_dev_get(skb->dev);
 376         if (indev)
 377                 list_for_each_entry(ifa, &indev->addr_list, if_list) {
 378                         if (ifa->flags & (IFA_F_TENTATIVE | IFA_F_DEPRECATED))
 379                                 continue;
 380
 381                         laddr = &ifa->addr;
 382                         break;
 383                 }
 384         rcu_read_unlock();
 385
 386         return laddr ? laddr : daddr;
 387 }
 388
 389 /**
 390  * tproxy_handle_time_wait6 - handle IPv6 TCP TIME_WAIT reopen redirections
 391  * @skb:        The skb being processed.
 392  * @tproto:     Transport protocol.
 393  * @thoff:      Transport protocol header offset.
 394  * @par:        Iptables target parameters.
 395  * @sk:         The TIME_WAIT TCP socket found by the lookup.
 396  *
 397  * We have to handle SYN packets arriving to TIME_WAIT sockets
 398  * differently: instead of reopening the connection we should rather
 399  * redirect the new connection to the proxy if there's a listener
 400  * socket present.
 401  *
 402  * tproxy_handle_time_wait6() consumes the socket reference passed in.
 403  *
 404  * Returns the listener socket if there's one, the TIME_WAIT socket if
 405  * no such listener is found, or NULL if the TCP header is incomplete.
 406  */
 407 static struct sock *
 408 tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
 409                          const struct xt_action_param *par,
 410                          struct sock *sk)
 411 {
 412         const struct ipv6hdr *iph = ipv6_hdr(skb);
 413         struct tcphdr _hdr, *hp;
 414         const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
 415
 416         hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
 417         if (hp == NULL) {
 418                 inet_twsk_put(inet_twsk(sk));
 419                 return NULL;
 420         }
 421
 422         if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
 423                 /* SYN to a TIME_WAIT socket, we'd rather redirect it
 424                  * to a listener socket if there's one */
 425                 struct sock *sk2;
 426
 427                 sk2 = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
 428                                             &iph->saddr,
 429                                             tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr),
 430                                             hp->source,
 431                                             tgi->lport ? tgi->lport : hp->dest,
 432                                             skb->dev, NFT_LOOKUP_LISTENER);
 433                 if (sk2) {
 434                         inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
 435                         inet_twsk_put(inet_twsk(sk));
 436                         sk = sk2;
 437                 }
 438         }
 439
 440         return sk;
 441 }
 442
 443 static unsigned int
 444 tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
 445 {
 446         const struct ipv6hdr *iph = ipv6_hdr(skb);
 447         const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
 448         struct udphdr _hdr, *hp;
 449         struct sock *sk;
 450         const struct in6_addr *laddr;
 451         __be16 lport;
 452         int thoff = 0;
 453         int tproto;
 454
 455         tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL);
 456         if (tproto < 0) {
 457                 pr_debug("unable to find transport header in IPv6 packet, dropping\n");
 458                 return NF_DROP;
 459         }
 460
 461         hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
 462         if (hp == NULL) {
 463                 pr_debug("unable to grab transport header contents in IPv6 packet, dropping\n");
 464                 return NF_DROP;
 465         }
 466
 467         /* check if there's an ongoing connection on the packet
 468          * addresses, this happens if the redirect already happened
 469          * and the current packet belongs to an already established
 470          * connection */
 471         sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
 472                                    &iph->saddr, &iph->daddr,
 473                                    hp->source, hp->dest,
 474                                    par->in, NFT_LOOKUP_ESTABLISHED);
 475
 476         laddr = tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr);
 477         lport = tgi->lport ? tgi->lport : hp->dest;
 478
 479         /* UDP has no TCP_TIME_WAIT state, so we never enter here */
 480         if (sk && sk->sk_state == TCP_TIME_WAIT)
 481                 /* reopening a TIME_WAIT connection needs special handling */
 482                 sk = tproxy_handle_time_wait6(skb, tproto, thoff, par, sk);
 483         else if (!sk)
 484                 /* no there's no established connection, check if
 485                  * there's a listener on the redirected addr/port */
 486                 sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
 487                                            &iph->saddr, laddr,
 488                                            hp->source, lport,
 489                                            par->in, NFT_LOOKUP_LISTENER);
 490
 491         /* NOTE: assign_sock consumes our sk reference */
 492         if (sk && tproxy_sk_is_transparent(sk)) {
 493                 /* This should be in a separate target, but we don't do multiple
 494                    targets on the same rule yet */
 495                 skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;
 496
 497                 pr_debug("redirecting: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
 498                          tproto, &iph->saddr, ntohs(hp->source),
 499                          laddr, ntohs(lport), skb->mark);
 500
 501                 nf_tproxy_assign_sock(skb, sk);
 502                 return NF_ACCEPT;
 503         }
 504
 505         pr_debug("no socket, dropping: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
 506                  tproto, &iph->saddr, ntohs(hp->source),
 507                  &iph->daddr, ntohs(hp->dest), skb->mark);
 508
 509         return NF_DROP;
 510 }
 511
 512 static int tproxy_tg6_check(const struct xt_tgchk_param *par)
 513 {
 514         const struct ip6t_ip6 *i = par->entryinfo;
 515
 516         if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP)
 517             && !(i->flags & IP6T_INV_PROTO))
 518                 return 0;
 519
 520         pr_info("Can be used only in combination with "
 521                 "either -p tcp or -p udp\n");
 522         return -EINVAL;
 523 }
 524 #endif
 525
 526 static int tproxy_tg4_check(const struct xt_tgchk_param *par)
 527 {
 528         const struct ipt_ip *i = par->entryinfo;
 529
 530         if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP)
 531             && !(i->invflags & IPT_INV_PROTO))
 532                 return 0;
 533
 534         pr_info("Can be used only in combination with "
 535                 "either -p tcp or -p udp\n");
 536         return -EINVAL;
 537 }
 538
 539 static struct xt_target tproxy_tg_reg[] __read_mostly = {
 540         {
 541                 .name           = "TPROXY",
 542                 .family         = NFPROTO_IPV4,
 543                 .table          = "mangle",
 544                 .target         = tproxy_tg4_v0,
 545                 .revision       = 0,
 546                 .targetsize     = sizeof(struct xt_tproxy_target_info),
 547                 .checkentry     = tproxy_tg4_check,
 548                 .hooks          = 1 << NF_INET_PRE_ROUTING,
 549                 .me             = THIS_MODULE,
 550         },
 551         {
 552                 .name           = "TPROXY",
 553                 .family         = NFPROTO_IPV4,
 554                 .table          = "mangle",
 555                 .target         = tproxy_tg4_v1,
 556                 .revision       = 1,
 557                 .targetsize     = sizeof(struct xt_tproxy_target_info_v1),
 558                 .checkentry     = tproxy_tg4_check,
 559                 .hooks          = 1 << NF_INET_PRE_ROUTING,
 560                 .me             = THIS_MODULE,
 561         },
 562 #ifdef XT_TPROXY_HAVE_IPV6
 563         {
 564                 .name           = "TPROXY",
 565                 .family         = NFPROTO_IPV6,
 566                 .table          = "mangle",
 567                 .target         = tproxy_tg6_v1,
 568                 .revision       = 1,
 569                 .targetsize     = sizeof(struct xt_tproxy_target_info_v1),
 570                 .checkentry     = tproxy_tg6_check,
 571                 .hooks          = 1 << NF_INET_PRE_ROUTING,
 572                 .me             = THIS_MODULE,
 573         },
 574 #endif
 575
 576 };
 577
 578 static int __init tproxy_tg_init(void)
 579 {
 580         nf_defrag_ipv4_enable();
 581 #ifdef XT_TPROXY_HAVE_IPV6
 582         nf_defrag_ipv6_enable();
 583 #endif
 584
 585         return xt_register_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
 586 }
 587
 588 static void __exit tproxy_tg_exit(void)
 589 {
 590         xt_unregister_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
 591 }
 592
 593 module_init(tproxy_tg_init);
 594 module_exit(tproxy_tg_exit);
 595 MODULE_LICENSE("GPL");
 596 MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
 597 MODULE_DESCRIPTION("Netfilter transparent proxy (TPROXY) target module.");
 598 MODULE_ALIAS("ipt_TPROXY");
 599 MODULE_ALIAS("ip6t_TPROXY");