net/ipv4/netfilter/nf_nat_core.c

   1 /* NAT for netfilter; shared with compatibility layer. */
   2
   3 /* (C) 1999-2001 Paul `Rusty' Russell
   4  * (C) 2002-2006 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/vmalloc.h>
  16 #include <net/checksum.h>
  17 #include <net/icmp.h>
  18 #include <net/ip.h>
  19 #include <net/tcp.h>  /* For tcp_prot in getorigdst */
  20 #include <linux/icmp.h>
  21 #include <linux/udp.h>
  22 #include <linux/jhash.h>
  23
  24 #include <linux/netfilter_ipv4.h>
  25 #include <net/netfilter/nf_conntrack.h>
  26 #include <net/netfilter/nf_conntrack_core.h>
  27 #include <net/netfilter/nf_nat.h>
  28 #include <net/netfilter/nf_nat_protocol.h>
  29 #include <net/netfilter/nf_nat_core.h>
  30 #include <net/netfilter/nf_nat_helper.h>
  31 #include <net/netfilter/nf_conntrack_helper.h>
  32 #include <net/netfilter/nf_conntrack_l3proto.h>
  33 #include <net/netfilter/nf_conntrack_l4proto.h>
  34
  35 #if 0
  36 #define DEBUGP printk
  37 #else
  38 #define DEBUGP(format, args...)
  39 #endif
  40
  41 static DEFINE_RWLOCK(nf_nat_lock);
  42
  43 static struct nf_conntrack_l3proto *l3proto = NULL;
  44
  45 /* Calculated at init based on memory size */
  46 static unsigned int nf_nat_htable_size;
  47
  48 static struct list_head *bysource;
  49
  50 #define MAX_IP_NAT_PROTO 256
  51 static struct nf_nat_protocol *nf_nat_protos[MAX_IP_NAT_PROTO];
  52
  53 static inline struct nf_nat_protocol *
  54 __nf_nat_proto_find(u_int8_t protonum)
  55 {
  56         return nf_nat_protos[protonum];
  57 }
  58
  59 struct nf_nat_protocol *
  60 nf_nat_proto_find_get(u_int8_t protonum)
  61 {
  62         struct nf_nat_protocol *p;
  63
  64         /* we need to disable preemption to make sure 'p' doesn't get
  65          * removed until we've grabbed the reference */
  66         preempt_disable();
  67         p = __nf_nat_proto_find(protonum);
  68         if (!try_module_get(p->me))
  69                 p = &nf_nat_unknown_protocol;
  70         preempt_enable();
  71
  72         return p;
  73 }
  74 EXPORT_SYMBOL_GPL(nf_nat_proto_find_get);
  75
  76 void
  77 nf_nat_proto_put(struct nf_nat_protocol *p)
  78 {
  79         module_put(p->me);
  80 }
  81 EXPORT_SYMBOL_GPL(nf_nat_proto_put);
  82
  83 /* We keep an extra hash for each conntrack, for fast searching. */
  84 static inline unsigned int
  85 hash_by_src(const struct nf_conntrack_tuple *tuple)
  86 {
  87         /* Original src, to ensure we map it consistently if poss. */
  88         return jhash_3words((__force u32)tuple->src.u3.ip, tuple->src.u.all,
  89                             tuple->dst.protonum, 0) % nf_nat_htable_size;
  90 }
  91
  92 /* Noone using conntrack by the time this called. */
  93 static void nf_nat_cleanup_conntrack(struct nf_conn *conn)
  94 {
  95         struct nf_conn_nat *nat;
  96         if (!(conn->status & IPS_NAT_DONE_MASK))
  97                 return;
  98
  99         nat = nfct_nat(conn);
 100         write_lock_bh(&nf_nat_lock);
 101         list_del(&nat->info.bysource);
 102         write_unlock_bh(&nf_nat_lock);
 103 }
 104
 105 /* Is this tuple already taken? (not by us) */
 106 int
 107 nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
 108                   const struct nf_conn *ignored_conntrack)
 109 {
 110         /* Conntrack tracking doesn't keep track of outgoing tuples; only
 111            incoming ones.  NAT means they don't have a fixed mapping,
 112            so we invert the tuple and look for the incoming reply.
 113
 114            We could keep a separate hash if this proves too slow. */
 115         struct nf_conntrack_tuple reply;
 116
 117         nf_ct_invert_tuplepr(&reply, tuple);
 118         return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
 119 }
 120 EXPORT_SYMBOL(nf_nat_used_tuple);
 121
 122 /* If we source map this tuple so reply looks like reply_tuple, will
 123  * that meet the constraints of range. */
 124 static int
 125 in_range(const struct nf_conntrack_tuple *tuple,
 126          const struct nf_nat_range *range)
 127 {
 128         struct nf_nat_protocol *proto;
 129
 130         proto = __nf_nat_proto_find(tuple->dst.protonum);
 131         /* If we are supposed to map IPs, then we must be in the
 132            range specified, otherwise let this drag us onto a new src IP. */
 133         if (range->flags & IP_NAT_RANGE_MAP_IPS) {
 134                 if (ntohl(tuple->src.u3.ip) < ntohl(range->min_ip) ||
 135                     ntohl(tuple->src.u3.ip) > ntohl(range->max_ip))
 136                         return 0;
 137         }
 138
 139         if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
 140             proto->in_range(tuple, IP_NAT_MANIP_SRC,
 141                             &range->min, &range->max))
 142                 return 1;
 143
 144         return 0;
 145 }
 146
 147 static inline int
 148 same_src(const struct nf_conn *ct,
 149          const struct nf_conntrack_tuple *tuple)
 150 {
 151         const struct nf_conntrack_tuple *t;
 152
 153         t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
 154         return (t->dst.protonum == tuple->dst.protonum &&
 155                 t->src.u3.ip == tuple->src.u3.ip &&
 156                 t->src.u.all == tuple->src.u.all);
 157 }
 158
 159 /* Only called for SRC manip */
 160 static int
 161 find_appropriate_src(const struct nf_conntrack_tuple *tuple,
 162                      struct nf_conntrack_tuple *result,
 163                      const struct nf_nat_range *range)
 164 {
 165         unsigned int h = hash_by_src(tuple);
 166         struct nf_conn_nat *nat;
 167         struct nf_conn *ct;
 168
 169         read_lock_bh(&nf_nat_lock);
 170         list_for_each_entry(nat, &bysource[h], info.bysource) {
 171                 ct = (struct nf_conn *)((char *)nat - offsetof(struct nf_conn, data));
 172                 if (same_src(ct, tuple)) {
 173                         /* Copy source part from reply tuple. */
 174                         nf_ct_invert_tuplepr(result,
 175                                        &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 176                         result->dst = tuple->dst;
 177
 178                         if (in_range(result, range)) {
 179                                 read_unlock_bh(&nf_nat_lock);
 180                                 return 1;
 181                         }
 182                 }
 183         }
 184         read_unlock_bh(&nf_nat_lock);
 185         return 0;
 186 }
 187
 188 /* For [FUTURE] fragmentation handling, we want the least-used
 189    src-ip/dst-ip/proto triple.  Fairness doesn't come into it.  Thus
 190    if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
 191    1-65535, we don't do pro-rata allocation based on ports; we choose
 192    the ip with the lowest src-ip/dst-ip/proto usage.
 193 */
 194 static void
 195 find_best_ips_proto(struct nf_conntrack_tuple *tuple,
 196                     const struct nf_nat_range *range,
 197                     const struct nf_conn *ct,
 198                     enum nf_nat_manip_type maniptype)
 199 {
 200         __be32 *var_ipp;
 201         /* Host order */
 202         u_int32_t minip, maxip, j;
 203
 204         /* No IP mapping?  Do nothing. */
 205         if (!(range->flags & IP_NAT_RANGE_MAP_IPS))
 206                 return;
 207
 208         if (maniptype == IP_NAT_MANIP_SRC)
 209                 var_ipp = &tuple->src.u3.ip;
 210         else
 211                 var_ipp = &tuple->dst.u3.ip;
 212
 213         /* Fast path: only one choice. */
 214         if (range->min_ip == range->max_ip) {
 215                 *var_ipp = range->min_ip;
 216                 return;
 217         }
 218
 219         /* Hashing source and destination IPs gives a fairly even
 220          * spread in practice (if there are a small number of IPs
 221          * involved, there usually aren't that many connections
 222          * anyway).  The consistency means that servers see the same
 223          * client coming from the same IP (some Internet Banking sites
 224          * like this), even across reboots. */
 225         minip = ntohl(range->min_ip);
 226         maxip = ntohl(range->max_ip);
 227         j = jhash_2words((__force u32)tuple->src.u3.ip,
 228                          (__force u32)tuple->dst.u3.ip, 0);
 229         *var_ipp = htonl(minip + j % (maxip - minip + 1));
 230 }
 231
 232 /* Manipulate the tuple into the range given.  For NF_IP_POST_ROUTING,
 233  * we change the source to map into the range.  For NF_IP_PRE_ROUTING
 234  * and NF_IP_LOCAL_OUT, we change the destination to map into the
 235  * range.  It might not be possible to get a unique tuple, but we try.
 236  * At worst (or if we race), we will end up with a final duplicate in
 237  * __ip_conntrack_confirm and drop the packet. */
 238 static void
 239 get_unique_tuple(struct nf_conntrack_tuple *tuple,
 240                  const struct nf_conntrack_tuple *orig_tuple,
 241                  const struct nf_nat_range *range,
 242                  struct nf_conn *ct,
 243                  enum nf_nat_manip_type maniptype)
 244 {
 245         struct nf_nat_protocol *proto;
 246
 247         /* 1) If this srcip/proto/src-proto-part is currently mapped,
 248            and that same mapping gives a unique tuple within the given
 249            range, use that.
 250
 251            This is only required for source (ie. NAT/masq) mappings.
 252            So far, we don't do local source mappings, so multiple
 253            manips not an issue.  */
 254         if (maniptype == IP_NAT_MANIP_SRC) {
 255                 if (find_appropriate_src(orig_tuple, tuple, range)) {
 256                         DEBUGP("get_unique_tuple: Found current src map\n");
 257                         if (!(range->flags & IP_NAT_RANGE_PROTO_RANDOM))
 258                                 if (!nf_nat_used_tuple(tuple, ct))
 259                                         return;
 260                 }
 261         }
 262
 263         /* 2) Select the least-used IP/proto combination in the given
 264            range. */
 265         *tuple = *orig_tuple;
 266         find_best_ips_proto(tuple, range, ct, maniptype);
 267
 268         /* 3) The per-protocol part of the manip is made to map into
 269            the range to make a unique tuple. */
 270
 271         proto = nf_nat_proto_find_get(orig_tuple->dst.protonum);
 272
 273         /* Change protocol info to have some randomization */
 274         if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) {
 275                 proto->unique_tuple(tuple, range, maniptype, ct);
 276                 nf_nat_proto_put(proto);
 277                 return;
 278         }
 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             !nf_nat_used_tuple(tuple, ct)) {
 284                 nf_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, ct);
 290
 291         nf_nat_proto_put(proto);
 292 }
 293
 294 unsigned int
 295 nf_nat_setup_info(struct nf_conn *ct,
 296                   const struct nf_nat_range *range,
 297                   unsigned int hooknum)
 298 {
 299         struct nf_conntrack_tuple curr_tuple, new_tuple;
 300         struct nf_conn_nat *nat = nfct_nat(ct);
 301         struct nf_nat_info *info = &nat->info;
 302         int have_to_hash = !(ct->status & IPS_NAT_DONE_MASK);
 303         enum nf_nat_manip_type maniptype = HOOK2MANIP(hooknum);
 304
 305         NF_CT_ASSERT(hooknum == NF_IP_PRE_ROUTING ||
 306                      hooknum == NF_IP_POST_ROUTING ||
 307                      hooknum == NF_IP_LOCAL_IN ||
 308                      hooknum == NF_IP_LOCAL_OUT);
 309         BUG_ON(nf_nat_initialized(ct, maniptype));
 310
 311         /* What we've got will look like inverse of reply. Normally
 312            this is what is in the conntrack, except for prior
 313            manipulations (future optimization: if num_manips == 0,
 314            orig_tp =
 315            conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */
 316         nf_ct_invert_tuplepr(&curr_tuple,
 317                              &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 318
 319         get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
 320
 321         if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
 322                 struct nf_conntrack_tuple reply;
 323
 324                 /* Alter conntrack table so will recognize replies. */
 325                 nf_ct_invert_tuplepr(&reply, &new_tuple);
 326                 nf_conntrack_alter_reply(ct, &reply);
 327
 328                 /* Non-atomic: we own this at the moment. */
 329                 if (maniptype == IP_NAT_MANIP_SRC)
 330                         ct->status |= IPS_SRC_NAT;
 331                 else
 332                         ct->status |= IPS_DST_NAT;
 333         }
 334
 335         /* Place in source hash if this is the first time. */
 336         if (have_to_hash) {
 337                 unsigned int srchash;
 338
 339                 srchash = hash_by_src(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 340                 write_lock_bh(&nf_nat_lock);
 341                 list_add(&info->bysource, &bysource[srchash]);
 342                 write_unlock_bh(&nf_nat_lock);
 343         }
 344
 345         /* It's done. */
 346         if (maniptype == IP_NAT_MANIP_DST)
 347                 set_bit(IPS_DST_NAT_DONE_BIT, &ct->status);
 348         else
 349                 set_bit(IPS_SRC_NAT_DONE_BIT, &ct->status);
 350
 351         return NF_ACCEPT;
 352 }
 353 EXPORT_SYMBOL(nf_nat_setup_info);
 354
 355 /* Returns true if succeeded. */
 356 static int
 357 manip_pkt(u_int16_t proto,
 358           struct sk_buff **pskb,
 359           unsigned int iphdroff,
 360           const struct nf_conntrack_tuple *target,
 361           enum nf_nat_manip_type maniptype)
 362 {
 363         struct iphdr *iph;
 364         struct nf_nat_protocol *p;
 365
 366         if (!skb_make_writable(pskb, iphdroff + sizeof(*iph)))
 367                 return 0;
 368
 369         iph = (void *)(*pskb)->data + iphdroff;
 370
 371         /* Manipulate protcol part. */
 372         p = nf_nat_proto_find_get(proto);
 373         if (!p->manip_pkt(pskb, iphdroff, target, maniptype)) {
 374                 nf_nat_proto_put(p);
 375                 return 0;
 376         }
 377         nf_nat_proto_put(p);
 378
 379         iph = (void *)(*pskb)->data + iphdroff;
 380
 381         if (maniptype == IP_NAT_MANIP_SRC) {
 382                 nf_csum_replace4(&iph->check, iph->saddr, target->src.u3.ip);
 383                 iph->saddr = target->src.u3.ip;
 384         } else {
 385                 nf_csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip);
 386                 iph->daddr = target->dst.u3.ip;
 387         }
 388         return 1;
 389 }
 390
 391 /* Do packet manipulations according to nf_nat_setup_info. */
 392 unsigned int nf_nat_packet(struct nf_conn *ct,
 393                            enum ip_conntrack_info ctinfo,
 394                            unsigned int hooknum,
 395                            struct sk_buff **pskb)
 396 {
 397         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 398         unsigned long statusbit;
 399         enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
 400
 401         if (mtype == IP_NAT_MANIP_SRC)
 402                 statusbit = IPS_SRC_NAT;
 403         else
 404                 statusbit = IPS_DST_NAT;
 405
 406         /* Invert if this is reply dir. */
 407         if (dir == IP_CT_DIR_REPLY)
 408                 statusbit ^= IPS_NAT_MASK;
 409
 410         /* Non-atomic: these bits don't change. */
 411         if (ct->status & statusbit) {
 412                 struct nf_conntrack_tuple target;
 413
 414                 /* We are aiming to look like inverse of other direction. */
 415                 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
 416
 417                 if (!manip_pkt(target.dst.protonum, pskb, 0, &target, mtype))
 418                         return NF_DROP;
 419         }
 420         return NF_ACCEPT;
 421 }
 422 EXPORT_SYMBOL_GPL(nf_nat_packet);
 423
 424 /* Dir is direction ICMP is coming from (opposite to packet it contains) */
 425 int nf_nat_icmp_reply_translation(struct nf_conn *ct,
 426                                   enum ip_conntrack_info ctinfo,
 427                                   unsigned int hooknum,
 428                                   struct sk_buff **pskb)
 429 {
 430         struct {
 431                 struct icmphdr icmp;
 432                 struct iphdr ip;
 433         } *inside;
 434         struct nf_conntrack_tuple inner, target;
 435         int hdrlen = (*pskb)->nh.iph->ihl * 4;
 436         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 437         unsigned long statusbit;
 438         enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
 439
 440         if (!skb_make_writable(pskb, hdrlen + sizeof(*inside)))
 441                 return 0;
 442
 443         inside = (void *)(*pskb)->data + (*pskb)->nh.iph->ihl*4;
 444
 445         /* We're actually going to mangle it beyond trivial checksum
 446            adjustment, so make sure the current checksum is correct. */
 447         if (nf_ip_checksum(*pskb, hooknum, hdrlen, 0))
 448                 return 0;
 449
 450         /* Must be RELATED */
 451         NF_CT_ASSERT((*pskb)->nfctinfo == IP_CT_RELATED ||
 452                      (*pskb)->nfctinfo == IP_CT_RELATED+IP_CT_IS_REPLY);
 453
 454         /* Redirects on non-null nats must be dropped, else they'll
 455            start talking to each other without our translation, and be
 456            confused... --RR */
 457         if (inside->icmp.type == ICMP_REDIRECT) {
 458                 /* If NAT isn't finished, assume it and drop. */
 459                 if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
 460                         return 0;
 461
 462                 if (ct->status & IPS_NAT_MASK)
 463                         return 0;
 464         }
 465
 466         DEBUGP("icmp_reply_translation: translating error %p manp %u dir %s\n",
 467                *pskb, manip, dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY");
 468
 469         if (!nf_ct_get_tuple(*pskb,
 470                              (*pskb)->nh.iph->ihl*4 + sizeof(struct icmphdr),
 471                              (*pskb)->nh.iph->ihl*4 +
 472                              sizeof(struct icmphdr) + inside->ip.ihl*4,
 473                              (u_int16_t)AF_INET,
 474                              inside->ip.protocol,
 475                              &inner,
 476                              l3proto,
 477                              __nf_ct_l4proto_find((u_int16_t)PF_INET,
 478                                                   inside->ip.protocol)))
 479                 return 0;
 480
 481         /* Change inner back to look like incoming packet.  We do the
 482            opposite manip on this hook to normal, because it might not
 483            pass all hooks (locally-generated ICMP).  Consider incoming
 484            packet: PREROUTING (DST manip), routing produces ICMP, goes
 485            through POSTROUTING (which must correct the DST manip). */
 486         if (!manip_pkt(inside->ip.protocol, pskb,
 487                        (*pskb)->nh.iph->ihl*4 + sizeof(inside->icmp),
 488                        &ct->tuplehash[!dir].tuple,
 489                        !manip))
 490                 return 0;
 491
 492         if ((*pskb)->ip_summed != CHECKSUM_PARTIAL) {
 493                 /* Reloading "inside" here since manip_pkt inner. */
 494                 inside = (void *)(*pskb)->data + (*pskb)->nh.iph->ihl*4;
 495                 inside->icmp.checksum = 0;
 496                 inside->icmp.checksum =
 497                         csum_fold(skb_checksum(*pskb, hdrlen,
 498                                                (*pskb)->len - hdrlen, 0));
 499         }
 500
 501         /* Change outer to look the reply to an incoming packet
 502          * (proto 0 means don't invert per-proto part). */
 503         if (manip == IP_NAT_MANIP_SRC)
 504                 statusbit = IPS_SRC_NAT;
 505         else
 506                 statusbit = IPS_DST_NAT;
 507
 508         /* Invert if this is reply dir. */
 509         if (dir == IP_CT_DIR_REPLY)
 510                 statusbit ^= IPS_NAT_MASK;
 511
 512         if (ct->status & statusbit) {
 513                 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
 514                 if (!manip_pkt(0, pskb, 0, &target, manip))
 515                         return 0;
 516         }
 517
 518         return 1;
 519 }
 520 EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation);
 521
 522 /* Protocol registration. */
 523 int nf_nat_protocol_register(struct nf_nat_protocol *proto)
 524 {
 525         int ret = 0;
 526
 527         write_lock_bh(&nf_nat_lock);
 528         if (nf_nat_protos[proto->protonum] != &nf_nat_unknown_protocol) {
 529                 ret = -EBUSY;
 530                 goto out;
 531         }
 532         nf_nat_protos[proto->protonum] = proto;
 533  out:
 534         write_unlock_bh(&nf_nat_lock);
 535         return ret;
 536 }
 537 EXPORT_SYMBOL(nf_nat_protocol_register);
 538
 539 /* Noone stores the protocol anywhere; simply delete it. */
 540 void nf_nat_protocol_unregister(struct nf_nat_protocol *proto)
 541 {
 542         write_lock_bh(&nf_nat_lock);
 543         nf_nat_protos[proto->protonum] = &nf_nat_unknown_protocol;
 544         write_unlock_bh(&nf_nat_lock);
 545
 546         /* Someone could be still looking at the proto in a bh. */
 547         synchronize_net();
 548 }
 549 EXPORT_SYMBOL(nf_nat_protocol_unregister);
 550
 551 #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
 552     defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
 553 int
 554 nf_nat_port_range_to_nfattr(struct sk_buff *skb,
 555                             const struct nf_nat_range *range)
 556 {
 557         NFA_PUT(skb, CTA_PROTONAT_PORT_MIN, sizeof(__be16),
 558                 &range->min.tcp.port);
 559         NFA_PUT(skb, CTA_PROTONAT_PORT_MAX, sizeof(__be16),
 560                 &range->max.tcp.port);
 561
 562         return 0;
 563
 564 nfattr_failure:
 565         return -1;
 566 }
 567 EXPORT_SYMBOL_GPL(nf_nat_port_nfattr_to_range);
 568
 569 int
 570 nf_nat_port_nfattr_to_range(struct nfattr *tb[], struct nf_nat_range *range)
 571 {
 572         int ret = 0;
 573
 574         /* we have to return whether we actually parsed something or not */
 575
 576         if (tb[CTA_PROTONAT_PORT_MIN-1]) {
 577                 ret = 1;
 578                 range->min.tcp.port =
 579                         *(__be16 *)NFA_DATA(tb[CTA_PROTONAT_PORT_MIN-1]);
 580         }
 581
 582         if (!tb[CTA_PROTONAT_PORT_MAX-1]) {
 583                 if (ret)
 584                         range->max.tcp.port = range->min.tcp.port;
 585         } else {
 586                 ret = 1;
 587                 range->max.tcp.port =
 588                         *(__be16 *)NFA_DATA(tb[CTA_PROTONAT_PORT_MAX-1]);
 589         }
 590
 591         return ret;
 592 }
 593 EXPORT_SYMBOL_GPL(nf_nat_port_range_to_nfattr);
 594 #endif
 595
 596 static int __init nf_nat_init(void)
 597 {
 598         size_t i;
 599
 600         /* Leave them the same for the moment. */
 601         nf_nat_htable_size = nf_conntrack_htable_size;
 602
 603         /* One vmalloc for both hash tables */
 604         bysource = vmalloc(sizeof(struct list_head) * nf_nat_htable_size);
 605         if (!bysource)
 606                 return -ENOMEM;
 607
 608         /* Sew in builtin protocols. */
 609         write_lock_bh(&nf_nat_lock);
 610         for (i = 0; i < MAX_IP_NAT_PROTO; i++)
 611                 nf_nat_protos[i] = &nf_nat_unknown_protocol;
 612         nf_nat_protos[IPPROTO_TCP] = &nf_nat_protocol_tcp;
 613         nf_nat_protos[IPPROTO_UDP] = &nf_nat_protocol_udp;
 614         nf_nat_protos[IPPROTO_ICMP] = &nf_nat_protocol_icmp;
 615         write_unlock_bh(&nf_nat_lock);
 616
 617         for (i = 0; i < nf_nat_htable_size; i++) {
 618                 INIT_LIST_HEAD(&bysource[i]);
 619         }
 620
 621         /* FIXME: Man, this is a hack.  <SIGH> */
 622         NF_CT_ASSERT(nf_conntrack_destroyed == NULL);
 623         nf_conntrack_destroyed = &nf_nat_cleanup_conntrack;
 624
 625         /* Initialize fake conntrack so that NAT will skip it */
 626         nf_conntrack_untracked.status |= IPS_NAT_DONE_MASK;
 627
 628         l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET);
 629         return 0;
 630 }
 631
 632 /* Clear NAT section of all conntracks, in case we're loaded again. */
 633 static int clean_nat(struct nf_conn *i, void *data)
 634 {
 635         struct nf_conn_nat *nat = nfct_nat(i);
 636
 637         if (!nat)
 638                 return 0;
 639         memset(nat, 0, sizeof(nat));
 640         i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST);
 641         return 0;
 642 }
 643
 644 static void __exit nf_nat_cleanup(void)
 645 {
 646         nf_ct_iterate_cleanup(&clean_nat, NULL);
 647         nf_conntrack_destroyed = NULL;
 648         vfree(bysource);
 649         nf_ct_l3proto_put(l3proto);
 650 }
 651
 652 MODULE_LICENSE("GPL");
 653
 654 module_init(nf_nat_init);
 655 module_exit(nf_nat_cleanup);