net/ipv4/netfilter/ip_nat_core.c

   1 /* NAT for netfilter; shared with compatibility layer. */
   2
   3 /* (C) 1999-2001 Paul `Rusty' Russell
   4  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   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/module.h>
  12 #include <linux/types.h>
  13 #include <linux/timer.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/netfilter_ipv4.h>
  16 #include <linux/vmalloc.h>
  17 #include <net/checksum.h>
  18 #include <net/icmp.h>
  19 #include <net/ip.h>
  20 #include <net/tcp.h>  /* For tcp_prot in getorigdst */
  21 #include <linux/icmp.h>
  22 #include <linux/udp.h>
  23 #include <linux/jhash.h>
  24
  25 #define ASSERT_READ_LOCK(x)
  26 #define ASSERT_WRITE_LOCK(x)
  27
  28 #include <linux/netfilter_ipv4/ip_conntrack.h>
  29 #include <linux/netfilter_ipv4/ip_conntrack_core.h>
  30 #include <linux/netfilter_ipv4/ip_conntrack_protocol.h>
  31 #include <linux/netfilter_ipv4/ip_nat.h>
  32 #include <linux/netfilter_ipv4/ip_nat_protocol.h>
  33 #include <linux/netfilter_ipv4/ip_nat_core.h>
  34 #include <linux/netfilter_ipv4/ip_nat_helper.h>
  35 #include <linux/netfilter_ipv4/ip_conntrack_helper.h>
  36 #include <linux/netfilter_ipv4/listhelp.h>
  37
  38 #if 0
  39 #define DEBUGP printk
  40 #else
  41 #define DEBUGP(format, args...)
  42 #endif
  43
  44 DEFINE_RWLOCK(ip_nat_lock);
  45
  46 /* Calculated at init based on memory size */
  47 static unsigned int ip_nat_htable_size;
  48
  49 static struct list_head *bysource;
  50
  51 #define MAX_IP_NAT_PROTO 256
  52 static struct ip_nat_protocol *ip_nat_protos[MAX_IP_NAT_PROTO];
  53
  54 static inline struct ip_nat_protocol *
  55 __ip_nat_proto_find(u_int8_t protonum)
  56 {
  57         return ip_nat_protos[protonum];
  58 }
  59
  60 struct ip_nat_protocol *
  61 ip_nat_proto_find_get(u_int8_t protonum)
  62 {
  63         struct ip_nat_protocol *p;
  64
  65         /* we need to disable preemption to make sure 'p' doesn't get
  66          * removed until we've grabbed the reference */
  67         preempt_disable();
  68         p = __ip_nat_proto_find(protonum);
  69         if (!try_module_get(p->me))
  70                 p = &ip_nat_unknown_protocol;
  71         preempt_enable();
  72
  73         return p;
  74 }
  75 EXPORT_SYMBOL_GPL(ip_nat_proto_find_get);
  76
  77 void
  78 ip_nat_proto_put(struct ip_nat_protocol *p)
  79 {
  80         module_put(p->me);
  81 }
  82 EXPORT_SYMBOL_GPL(ip_nat_proto_put);
  83
  84 /* We keep an extra hash for each conntrack, for fast searching. */
  85 static inline unsigned int
  86 hash_by_src(const struct ip_conntrack_tuple *tuple)
  87 {
  88         /* Original src, to ensure we map it consistently if poss. */
  89         return jhash_3words(tuple->src.ip, tuple->src.u.all,
  90                             tuple->dst.protonum, 0) % ip_nat_htable_size;
  91 }
  92
  93 /* Noone using conntrack by the time this called. */
  94 static void ip_nat_cleanup_conntrack(struct ip_conntrack *conn)
  95 {
  96         if (!(conn->status & IPS_NAT_DONE_MASK))
  97                 return;
  98
  99         write_lock_bh(&ip_nat_lock);
 100         list_del(&conn->nat.info.bysource);
 101         write_unlock_bh(&ip_nat_lock);
 102 }
 103
 104 /* We do checksum mangling, so if they were wrong before they're still
 105  * wrong.  Also works for incomplete packets (eg. ICMP dest
 106  * unreachables.) */
 107 u_int16_t
 108 ip_nat_cheat_check(u_int32_t oldvalinv, u_int32_t newval, u_int16_t oldcheck)
 109 {
 110         u_int32_t diffs[] = { oldvalinv, newval };
 111         return csum_fold(csum_partial((char *)diffs, sizeof(diffs),
 112                                       oldcheck^0xFFFF));
 113 }
 114 EXPORT_SYMBOL(ip_nat_cheat_check);
 115
 116 /* Is this tuple already taken? (not by us) */
 117 int
 118 ip_nat_used_tuple(const struct ip_conntrack_tuple *tuple,
 119                   const struct ip_conntrack *ignored_conntrack)
 120 {
 121         /* Conntrack tracking doesn't keep track of outgoing tuples; only
 122            incoming ones.  NAT means they don't have a fixed mapping,
 123            so we invert the tuple and look for the incoming reply.
 124
 125            We could keep a separate hash if this proves too slow. */
 126         struct ip_conntrack_tuple reply;
 127
 128         invert_tuplepr(&reply, tuple);
 129         return ip_conntrack_tuple_taken(&reply, ignored_conntrack);
 130 }
 131 EXPORT_SYMBOL(ip_nat_used_tuple);
 132
 133 /* If we source map this tuple so reply looks like reply_tuple, will
 134  * that meet the constraints of range. */
 135 static int
 136 in_range(const struct ip_conntrack_tuple *tuple,
 137          const struct ip_nat_range *range)
 138 {
 139         struct ip_nat_protocol *proto =
 140                                 __ip_nat_proto_find(tuple->dst.protonum);
 141
 142         /* If we are supposed to map IPs, then we must be in the
 143            range specified, otherwise let this drag us onto a new src IP. */
 144         if (range->flags & IP_NAT_RANGE_MAP_IPS) {
 145                 if (ntohl(tuple->src.ip) < ntohl(range->min_ip)
 146                     || ntohl(tuple->src.ip) > ntohl(range->max_ip))
 147                         return 0;
 148         }
 149
 150         if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)
 151             || proto->in_range(tuple, IP_NAT_MANIP_SRC,
 152                                &range->min, &range->max))
 153                 return 1;
 154
 155         return 0;
 156 }
 157
 158 static inline int
 159 same_src(const struct ip_conntrack *ct,
 160          const struct ip_conntrack_tuple *tuple)
 161 {
 162         return (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum
 163                 == tuple->dst.protonum
 164                 && ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip
 165                 == tuple->src.ip
 166                 && ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all
 167                 == tuple->src.u.all);
 168 }
 169
 170 /* Only called for SRC manip */
 171 static int
 172 find_appropriate_src(const struct ip_conntrack_tuple *tuple,
 173                      struct ip_conntrack_tuple *result,
 174                      const struct ip_nat_range *range)
 175 {
 176         unsigned int h = hash_by_src(tuple);
 177         struct ip_conntrack *ct;
 178
 179         read_lock_bh(&ip_nat_lock);
 180         list_for_each_entry(ct, &bysource[h], nat.info.bysource) {
 181                 if (same_src(ct, tuple)) {
 182                         /* Copy source part from reply tuple. */
 183                         invert_tuplepr(result,
 184                                        &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 185                         result->dst = tuple->dst;
 186
 187                         if (in_range(result, range)) {
 188                                 read_unlock_bh(&ip_nat_lock);
 189                                 return 1;
 190                         }
 191                 }
 192         }
 193         read_unlock_bh(&ip_nat_lock);
 194         return 0;
 195 }
 196
 197 /* For [FUTURE] fragmentation handling, we want the least-used
 198    src-ip/dst-ip/proto triple.  Fairness doesn't come into it.  Thus
 199    if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
 200    1-65535, we don't do pro-rata allocation based on ports; we choose
 201    the ip with the lowest src-ip/dst-ip/proto usage.
 202 */
 203 static void
 204 find_best_ips_proto(struct ip_conntrack_tuple *tuple,
 205                     const struct ip_nat_range *range,
 206                     const struct ip_conntrack *conntrack,
 207                     enum ip_nat_manip_type maniptype)
 208 {
 209         u_int32_t *var_ipp;
 210         /* Host order */
 211         u_int32_t minip, maxip, j;
 212
 213         /* No IP mapping?  Do nothing. */
 214         if (!(range->flags & IP_NAT_RANGE_MAP_IPS))
 215                 return;
 216
 217         if (maniptype == IP_NAT_MANIP_SRC)
 218                 var_ipp = &tuple->src.ip;
 219         else
 220                 var_ipp = &tuple->dst.ip;
 221
 222         /* Fast path: only one choice. */
 223         if (range->min_ip == range->max_ip) {
 224                 *var_ipp = range->min_ip;
 225                 return;
 226         }
 227
 228         /* Hashing source and destination IPs gives a fairly even
 229          * spread in practice (if there are a small number of IPs
 230          * involved, there usually aren't that many connections
 231          * anyway).  The consistency means that servers see the same
 232          * client coming from the same IP (some Internet Banking sites
 233          * like this), even across reboots. */
 234         minip = ntohl(range->min_ip);
 235         maxip = ntohl(range->max_ip);
 236         j = jhash_2words(tuple->src.ip, tuple->dst.ip, 0);
 237         *var_ipp = htonl(minip + j % (maxip - minip + 1));
 238 }
 239
 240 /* Manipulate the tuple into the range given.  For NF_IP_POST_ROUTING,
 241  * we change the source to map into the range.  For NF_IP_PRE_ROUTING
 242  * and NF_IP_LOCAL_OUT, we change the destination to map into the
 243  * range.  It might not be possible to get a unique tuple, but we try.
 244  * At worst (or if we race), we will end up with a final duplicate in
 245  * __ip_conntrack_confirm and drop the packet. */
 246 static void
 247 get_unique_tuple(struct ip_conntrack_tuple *tuple,
 248                  const struct ip_conntrack_tuple *orig_tuple,
 249                  const struct ip_nat_range *range,
 250                  struct ip_conntrack *conntrack,
 251                  enum ip_nat_manip_type maniptype)
 252 {
 253         struct ip_nat_protocol *proto;
 254
 255         /* 1) If this srcip/proto/src-proto-part is currently mapped,
 256            and that same mapping gives a unique tuple within the given
 257            range, use that.
 258
 259            This is only required for source (ie. NAT/masq) mappings.
 260            So far, we don't do local source mappings, so multiple
 261            manips not an issue.  */
 262         if (maniptype == IP_NAT_MANIP_SRC) {
 263                 if (find_appropriate_src(orig_tuple, tuple, range)) {
 264                         DEBUGP("get_unique_tuple: Found current src map\n");
 265                         if (!ip_nat_used_tuple(tuple, conntrack))
 266                                 return;
 267                 }
 268         }
 269
 270         /* 2) Select the least-used IP/proto combination in the given
 271            range. */
 272         *tuple = *orig_tuple;
 273         find_best_ips_proto(tuple, range, conntrack, maniptype);
 274
 275         /* 3) The per-protocol part of the manip is made to map into
 276            the range to make a unique tuple. */
 277
 278         proto = ip_nat_proto_find_get(orig_tuple->dst.protonum);
 279
 280         /* Only bother mapping if it's not already in range and unique */
 281         if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)
 282              || proto->in_range(tuple, maniptype, &range->min, &range->max))
 283             && !ip_nat_used_tuple(tuple, conntrack)) {
 284                 ip_nat_proto_put(proto);
 285                 return;
 286         }
 287
 288         /* Last change: get protocol to try to obtain unique tuple. */
 289         proto->unique_tuple(tuple, range, maniptype, conntrack);
 290
 291         ip_nat_proto_put(proto);
 292 }
 293
 294 unsigned int
 295 ip_nat_setup_info(struct ip_conntrack *conntrack,
 296                   const struct ip_nat_range *range,
 297                   unsigned int hooknum)
 298 {
 299         struct ip_conntrack_tuple curr_tuple, new_tuple;
 300         struct ip_nat_info *info = &conntrack->nat.info;
 301         int have_to_hash = !(conntrack->status & IPS_NAT_DONE_MASK);
 302         enum ip_nat_manip_type maniptype = HOOK2MANIP(hooknum);
 303
 304         IP_NF_ASSERT(hooknum == NF_IP_PRE_ROUTING
 305                      || hooknum == NF_IP_POST_ROUTING
 306                      || hooknum == NF_IP_LOCAL_IN
 307                      || hooknum == NF_IP_LOCAL_OUT);
 308         BUG_ON(ip_nat_initialized(conntrack, maniptype));
 309
 310         /* What we've got will look like inverse of reply. Normally
 311            this is what is in the conntrack, except for prior
 312            manipulations (future optimization: if num_manips == 0,
 313            orig_tp =
 314            conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */
 315         invert_tuplepr(&curr_tuple,
 316                        &conntrack->tuplehash[IP_CT_DIR_REPLY].tuple);
 317
 318         get_unique_tuple(&new_tuple, &curr_tuple, range, conntrack, maniptype);
 319
 320         if (!ip_ct_tuple_equal(&new_tuple, &curr_tuple)) {
 321                 struct ip_conntrack_tuple reply;
 322
 323                 /* Alter conntrack table so will recognize replies. */
 324                 invert_tuplepr(&reply, &new_tuple);
 325                 ip_conntrack_alter_reply(conntrack, &reply);
 326
 327                 /* Non-atomic: we own this at the moment. */
 328                 if (maniptype == IP_NAT_MANIP_SRC)
 329                         conntrack->status |= IPS_SRC_NAT;
 330                 else
 331                         conntrack->status |= IPS_DST_NAT;
 332         }
 333
 334         /* Place in source hash if this is the first time. */
 335         if (have_to_hash) {
 336                 unsigned int srchash
 337                         = hash_by_src(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL]
 338                                       .tuple);
 339                 write_lock_bh(&ip_nat_lock);
 340                 list_add(&info->bysource, &bysource[srchash]);
 341                 write_unlock_bh(&ip_nat_lock);
 342         }
 343
 344         /* It's done. */
 345         if (maniptype == IP_NAT_MANIP_DST)
 346                 set_bit(IPS_DST_NAT_DONE_BIT, &conntrack->status);
 347         else
 348                 set_bit(IPS_SRC_NAT_DONE_BIT, &conntrack->status);
 349
 350         return NF_ACCEPT;
 351 }
 352 EXPORT_SYMBOL(ip_nat_setup_info);
 353
 354 /* Returns true if succeeded. */
 355 static int
 356 manip_pkt(u_int16_t proto,
 357           struct sk_buff **pskb,
 358           unsigned int iphdroff,
 359           const struct ip_conntrack_tuple *target,
 360           enum ip_nat_manip_type maniptype)
 361 {
 362         struct iphdr *iph;
 363         struct ip_nat_protocol *p;
 364
 365         if (!skb_make_writable(pskb, iphdroff + sizeof(*iph)))
 366                 return 0;
 367
 368         iph = (void *)(*pskb)->data + iphdroff;
 369
 370         /* Manipulate protcol part. */
 371         p = ip_nat_proto_find_get(proto);
 372         if (!p->manip_pkt(pskb, iphdroff, target, maniptype)) {
 373                 ip_nat_proto_put(p);
 374                 return 0;
 375         }
 376         ip_nat_proto_put(p);
 377
 378         iph = (void *)(*pskb)->data + iphdroff;
 379
 380         if (maniptype == IP_NAT_MANIP_SRC) {
 381                 iph->check = ip_nat_cheat_check(~iph->saddr, target->src.ip,
 382                                                 iph->check);
 383                 iph->saddr = target->src.ip;
 384         } else {
 385                 iph->check = ip_nat_cheat_check(~iph->daddr, target->dst.ip,
 386                                                 iph->check);
 387                 iph->daddr = target->dst.ip;
 388         }
 389         return 1;
 390 }
 391
 392 /* Do packet manipulations according to ip_nat_setup_info. */
 393 unsigned int ip_nat_packet(struct ip_conntrack *ct,
 394                            enum ip_conntrack_info ctinfo,
 395                            unsigned int hooknum,
 396                            struct sk_buff **pskb)
 397 {
 398         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 399         unsigned long statusbit;
 400         enum ip_nat_manip_type mtype = HOOK2MANIP(hooknum);
 401
 402         if (mtype == IP_NAT_MANIP_SRC)
 403                 statusbit = IPS_SRC_NAT;
 404         else
 405                 statusbit = IPS_DST_NAT;
 406
 407         /* Invert if this is reply dir. */
 408         if (dir == IP_CT_DIR_REPLY)
 409                 statusbit ^= IPS_NAT_MASK;
 410
 411         /* Non-atomic: these bits don't change. */
 412         if (ct->status & statusbit) {
 413                 struct ip_conntrack_tuple target;
 414
 415                 /* We are aiming to look like inverse of other direction. */
 416                 invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
 417
 418                 if (!manip_pkt(target.dst.protonum, pskb, 0, &target, mtype))
 419                         return NF_DROP;
 420         }
 421         return NF_ACCEPT;
 422 }
 423 EXPORT_SYMBOL_GPL(ip_nat_packet);
 424
 425 /* Dir is direction ICMP is coming from (opposite to packet it contains) */
 426 int ip_nat_icmp_reply_translation(struct sk_buff **pskb,
 427                                   struct ip_conntrack *ct,
 428                                   enum ip_nat_manip_type manip,
 429                                   enum ip_conntrack_dir dir)
 430 {
 431         struct {
 432                 struct icmphdr icmp;
 433                 struct iphdr ip;
 434         } *inside;
 435         struct ip_conntrack_tuple inner, target;
 436         int hdrlen = (*pskb)->nh.iph->ihl * 4;
 437         unsigned long statusbit;
 438
 439         if (!skb_make_writable(pskb, hdrlen + sizeof(*inside)))
 440                 return 0;
 441
 442         inside = (void *)(*pskb)->data + (*pskb)->nh.iph->ihl*4;
 443
 444         /* We're actually going to mangle it beyond trivial checksum
 445            adjustment, so make sure the current checksum is correct. */
 446         if ((*pskb)->ip_summed != CHECKSUM_UNNECESSARY) {
 447                 hdrlen = (*pskb)->nh.iph->ihl * 4;
 448                 if ((u16)csum_fold(skb_checksum(*pskb, hdrlen,
 449                                                 (*pskb)->len - hdrlen, 0)))
 450                         return 0;
 451         }
 452
 453         /* Must be RELATED */
 454         IP_NF_ASSERT((*pskb)->nfctinfo == IP_CT_RELATED ||
 455                      (*pskb)->nfctinfo == IP_CT_RELATED+IP_CT_IS_REPLY);
 456
 457         /* Redirects on non-null nats must be dropped, else they'll
 458            start talking to each other without our translation, and be
 459            confused... --RR */
 460         if (inside->icmp.type == ICMP_REDIRECT) {
 461                 /* If NAT isn't finished, assume it and drop. */
 462                 if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
 463                         return 0;
 464
 465                 if (ct->status & IPS_NAT_MASK)
 466                         return 0;
 467         }
 468
 469         DEBUGP("icmp_reply_translation: translating error %p manp %u dir %s\n",
 470                *pskb, manip, dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY");
 471
 472         if (!ip_ct_get_tuple(&inside->ip, *pskb, (*pskb)->nh.iph->ihl*4 +
 473                              sizeof(struct icmphdr) + inside->ip.ihl*4,
 474                              &inner,
 475                              __ip_conntrack_proto_find(inside->ip.protocol)))
 476                 return 0;
 477
 478         /* Change inner back to look like incoming packet.  We do the
 479            opposite manip on this hook to normal, because it might not
 480            pass all hooks (locally-generated ICMP).  Consider incoming
 481            packet: PREROUTING (DST manip), routing produces ICMP, goes
 482            through POSTROUTING (which must correct the DST manip). */
 483         if (!manip_pkt(inside->ip.protocol, pskb,
 484                        (*pskb)->nh.iph->ihl*4
 485                        + sizeof(inside->icmp),
 486                        &ct->tuplehash[!dir].tuple,
 487                        !manip))
 488                 return 0;
 489
 490         /* Reloading "inside" here since manip_pkt inner. */
 491         inside = (void *)(*pskb)->data + (*pskb)->nh.iph->ihl*4;
 492         inside->icmp.checksum = 0;
 493         inside->icmp.checksum = csum_fold(skb_checksum(*pskb, hdrlen,
 494                                                        (*pskb)->len - hdrlen,
 495                                                        0));
 496
 497         /* Change outer to look the reply to an incoming packet
 498          * (proto 0 means don't invert per-proto part). */
 499         if (manip == IP_NAT_MANIP_SRC)
 500                 statusbit = IPS_SRC_NAT;
 501         else
 502                 statusbit = IPS_DST_NAT;
 503
 504         /* Invert if this is reply dir. */
 505         if (dir == IP_CT_DIR_REPLY)
 506                 statusbit ^= IPS_NAT_MASK;
 507
 508         if (ct->status & statusbit) {
 509                 invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
 510                 if (!manip_pkt(0, pskb, 0, &target, manip))
 511                         return 0;
 512         }
 513
 514         return 1;
 515 }
 516 EXPORT_SYMBOL_GPL(ip_nat_icmp_reply_translation);
 517
 518 /* Protocol registration. */
 519 int ip_nat_protocol_register(struct ip_nat_protocol *proto)
 520 {
 521         int ret = 0;
 522
 523         write_lock_bh(&ip_nat_lock);
 524         if (ip_nat_protos[proto->protonum] != &ip_nat_unknown_protocol) {
 525                 ret = -EBUSY;
 526                 goto out;
 527         }
 528         ip_nat_protos[proto->protonum] = proto;
 529  out:
 530         write_unlock_bh(&ip_nat_lock);
 531         return ret;
 532 }
 533 EXPORT_SYMBOL(ip_nat_protocol_register);
 534
 535 /* Noone stores the protocol anywhere; simply delete it. */
 536 void ip_nat_protocol_unregister(struct ip_nat_protocol *proto)
 537 {
 538         write_lock_bh(&ip_nat_lock);
 539         ip_nat_protos[proto->protonum] = &ip_nat_unknown_protocol;
 540         write_unlock_bh(&ip_nat_lock);
 541
 542         /* Someone could be still looking at the proto in a bh. */
 543         synchronize_net();
 544 }
 545 EXPORT_SYMBOL(ip_nat_protocol_unregister);
 546
 547 #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
 548     defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
 549 int
 550 ip_nat_port_range_to_nfattr(struct sk_buff *skb,
 551                             const struct ip_nat_range *range)
 552 {
 553         NFA_PUT(skb, CTA_PROTONAT_PORT_MIN, sizeof(u_int16_t),
 554                 &range->min.tcp.port);
 555         NFA_PUT(skb, CTA_PROTONAT_PORT_MAX, sizeof(u_int16_t),
 556                 &range->max.tcp.port);
 557
 558         return 0;
 559
 560 nfattr_failure:
 561         return -1;
 562 }
 563
 564 int
 565 ip_nat_port_nfattr_to_range(struct nfattr *tb[], struct ip_nat_range *range)
 566 {
 567         int ret = 0;
 568
 569         /* we have to return whether we actually parsed something or not */
 570
 571         if (tb[CTA_PROTONAT_PORT_MIN-1]) {
 572                 ret = 1;
 573                 range->min.tcp.port =
 574                         *(u_int16_t *)NFA_DATA(tb[CTA_PROTONAT_PORT_MIN-1]);
 575         }
 576
 577         if (!tb[CTA_PROTONAT_PORT_MAX-1]) {
 578                 if (ret)
 579                         range->max.tcp.port = range->min.tcp.port;
 580         } else {
 581                 ret = 1;
 582                 range->max.tcp.port =
 583                         *(u_int16_t *)NFA_DATA(tb[CTA_PROTONAT_PORT_MAX-1]);
 584         }
 585
 586         return ret;
 587 }
 588 EXPORT_SYMBOL_GPL(ip_nat_port_nfattr_to_range);
 589 EXPORT_SYMBOL_GPL(ip_nat_port_range_to_nfattr);
 590 #endif
 591
 592 static int __init ip_nat_init(void)
 593 {
 594         size_t i;
 595
 596         /* Leave them the same for the moment. */
 597         ip_nat_htable_size = ip_conntrack_htable_size;
 598
 599         /* One vmalloc for both hash tables */
 600         bysource = vmalloc(sizeof(struct list_head) * ip_nat_htable_size);
 601         if (!bysource)
 602                 return -ENOMEM;
 603
 604         /* Sew in builtin protocols. */
 605         write_lock_bh(&ip_nat_lock);
 606         for (i = 0; i < MAX_IP_NAT_PROTO; i++)
 607                 ip_nat_protos[i] = &ip_nat_unknown_protocol;
 608         ip_nat_protos[IPPROTO_TCP] = &ip_nat_protocol_tcp;
 609         ip_nat_protos[IPPROTO_UDP] = &ip_nat_protocol_udp;
 610         ip_nat_protos[IPPROTO_ICMP] = &ip_nat_protocol_icmp;
 611         write_unlock_bh(&ip_nat_lock);
 612
 613         for (i = 0; i < ip_nat_htable_size; i++) {
 614                 INIT_LIST_HEAD(&bysource[i]);
 615         }
 616
 617         /* FIXME: Man, this is a hack.  <SIGH> */
 618         IP_NF_ASSERT(ip_conntrack_destroyed == NULL);
 619         ip_conntrack_destroyed = &ip_nat_cleanup_conntrack;
 620
 621         /* Initialize fake conntrack so that NAT will skip it */
 622         ip_conntrack_untracked.status |= IPS_NAT_DONE_MASK;
 623         return 0;
 624 }
 625
 626 /* Clear NAT section of all conntracks, in case we're loaded again. */
 627 static int clean_nat(struct ip_conntrack *i, void *data)
 628 {
 629         memset(&i->nat, 0, sizeof(i->nat));
 630         i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST);
 631         return 0;
 632 }
 633
 634 static void __exit ip_nat_cleanup(void)
 635 {
 636         ip_ct_iterate_cleanup(&clean_nat, NULL);
 637         ip_conntrack_destroyed = NULL;
 638         vfree(bysource);
 639 }
 640
 641 MODULE_LICENSE("GPL");
 642
 643 module_init(ip_nat_init);
 644 module_exit(ip_nat_cleanup);