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 rcu_dereference(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         rcu_read_lock();
  65         p = __nf_nat_proto_find(protonum);
  66         if (!try_module_get(p->me))
  67                 p = &nf_nat_unknown_protocol;
  68         rcu_read_unlock();
  69
  70         return p;
  71 }
  72 EXPORT_SYMBOL_GPL(nf_nat_proto_find_get);
  73
  74 void
  75 nf_nat_proto_put(struct nf_nat_protocol *p)
  76 {
  77         module_put(p->me);
  78 }
  79 EXPORT_SYMBOL_GPL(nf_nat_proto_put);
  80
  81 /* We keep an extra hash for each conntrack, for fast searching. */
  82 static inline unsigned int
  83 hash_by_src(const struct nf_conntrack_tuple *tuple)
  84 {
  85         /* Original src, to ensure we map it consistently if poss. */
  86         return jhash_3words((__force u32)tuple->src.u3.ip, tuple->src.u.all,
  87                             tuple->dst.protonum, 0) % nf_nat_htable_size;
  88 }
  89
  90 /* Noone using conntrack by the time this called. */
  91 static void nf_nat_cleanup_conntrack(struct nf_conn *conn)
  92 {
  93         struct nf_conn_nat *nat;
  94         if (!(conn->status & IPS_NAT_DONE_MASK))
  95                 return;
  96
  97         nat = nfct_nat(conn);
  98         write_lock_bh(&nf_nat_lock);
  99         list_del(&nat->info.bysource);
 100         nat->info.ct = NULL;
 101         write_unlock_bh(&nf_nat_lock);
 102 }
 103
 104 /* Is this tuple already taken? (not by us) */
 105 int
 106 nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
 107                   const struct nf_conn *ignored_conntrack)
 108 {
 109         /* Conntrack tracking doesn't keep track of outgoing tuples; only
 110            incoming ones.  NAT means they don't have a fixed mapping,
 111            so we invert the tuple and look for the incoming reply.
 112
 113            We could keep a separate hash if this proves too slow. */
 114         struct nf_conntrack_tuple reply;
 115
 116         nf_ct_invert_tuplepr(&reply, tuple);
 117         return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
 118 }
 119 EXPORT_SYMBOL(nf_nat_used_tuple);
 120
 121 /* If we source map this tuple so reply looks like reply_tuple, will
 122  * that meet the constraints of range. */
 123 static int
 124 in_range(const struct nf_conntrack_tuple *tuple,
 125          const struct nf_nat_range *range)
 126 {
 127         struct nf_nat_protocol *proto;
 128         int ret = 0;
 129
 130         /* If we are supposed to map IPs, then we must be in the
 131            range specified, otherwise let this drag us onto a new src IP. */
 132         if (range->flags & IP_NAT_RANGE_MAP_IPS) {
 133                 if (ntohl(tuple->src.u3.ip) < ntohl(range->min_ip) ||
 134                     ntohl(tuple->src.u3.ip) > ntohl(range->max_ip))
 135                         return 0;
 136         }
 137
 138         rcu_read_lock();
 139         proto = __nf_nat_proto_find(tuple->dst.protonum);
 140         if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
 141             proto->in_range(tuple, IP_NAT_MANIP_SRC,
 142                             &range->min, &range->max))
 143                 ret = 1;
 144         rcu_read_unlock();
 145
 146         return ret;
 147 }
 148
 149 static inline int
 150 same_src(const struct nf_conn *ct,
 151          const struct nf_conntrack_tuple *tuple)
 152 {
 153         const struct nf_conntrack_tuple *t;
 154
 155         t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
 156         return (t->dst.protonum == tuple->dst.protonum &&
 157                 t->src.u3.ip == tuple->src.u3.ip &&
 158                 t->src.u.all == tuple->src.u.all);
 159 }
 160
 161 /* Only called for SRC manip */
 162 static int
 163 find_appropriate_src(const struct nf_conntrack_tuple *tuple,
 164                      struct nf_conntrack_tuple *result,
 165                      const struct nf_nat_range *range)
 166 {
 167         unsigned int h = hash_by_src(tuple);
 168         struct nf_conn_nat *nat;
 169         struct nf_conn *ct;
 170
 171         read_lock_bh(&nf_nat_lock);
 172         list_for_each_entry(nat, &bysource[h], info.bysource) {
 173                 ct = nat->info.ct;
 174                 if (same_src(ct, tuple)) {
 175                         /* Copy source part from reply tuple. */
 176                         nf_ct_invert_tuplepr(result,
 177                                        &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 178                         result->dst = tuple->dst;
 179
 180                         if (in_range(result, range)) {
 181                                 read_unlock_bh(&nf_nat_lock);
 182                                 return 1;
 183                         }
 184                 }
 185         }
 186         read_unlock_bh(&nf_nat_lock);
 187         return 0;
 188 }
 189
 190 /* For [FUTURE] fragmentation handling, we want the least-used
 191    src-ip/dst-ip/proto triple.  Fairness doesn't come into it.  Thus
 192    if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
 193    1-65535, we don't do pro-rata allocation based on ports; we choose
 194    the ip with the lowest src-ip/dst-ip/proto usage.
 195 */
 196 static void
 197 find_best_ips_proto(struct nf_conntrack_tuple *tuple,
 198                     const struct nf_nat_range *range,
 199                     const struct nf_conn *ct,
 200                     enum nf_nat_manip_type maniptype)
 201 {
 202         __be32 *var_ipp;
 203         /* Host order */
 204         u_int32_t minip, maxip, j;
 205
 206         /* No IP mapping?  Do nothing. */
 207         if (!(range->flags & IP_NAT_RANGE_MAP_IPS))
 208                 return;
 209
 210         if (maniptype == IP_NAT_MANIP_SRC)
 211                 var_ipp = &tuple->src.u3.ip;
 212         else
 213                 var_ipp = &tuple->dst.u3.ip;
 214
 215         /* Fast path: only one choice. */
 216         if (range->min_ip == range->max_ip) {
 217                 *var_ipp = range->min_ip;
 218                 return;
 219         }
 220
 221         /* Hashing source and destination IPs gives a fairly even
 222          * spread in practice (if there are a small number of IPs
 223          * involved, there usually aren't that many connections
 224          * anyway).  The consistency means that servers see the same
 225          * client coming from the same IP (some Internet Banking sites
 226          * like this), even across reboots. */
 227         minip = ntohl(range->min_ip);
 228         maxip = ntohl(range->max_ip);
 229         j = jhash_2words((__force u32)tuple->src.u3.ip,
 230                          (__force u32)tuple->dst.u3.ip, 0);
 231         *var_ipp = htonl(minip + j % (maxip - minip + 1));
 232 }
 233
 234 /* Manipulate the tuple into the range given.  For NF_IP_POST_ROUTING,
 235  * we change the source to map into the range.  For NF_IP_PRE_ROUTING
 236  * and NF_IP_LOCAL_OUT, we change the destination to map into the
 237  * range.  It might not be possible to get a unique tuple, but we try.
 238  * At worst (or if we race), we will end up with a final duplicate in
 239  * __ip_conntrack_confirm and drop the packet. */
 240 static void
 241 get_unique_tuple(struct nf_conntrack_tuple *tuple,
 242                  const struct nf_conntrack_tuple *orig_tuple,
 243                  const struct nf_nat_range *range,
 244                  struct nf_conn *ct,
 245                  enum nf_nat_manip_type maniptype)
 246 {
 247         struct nf_nat_protocol *proto;
 248
 249         /* 1) If this srcip/proto/src-proto-part is currently mapped,
 250            and that same mapping gives a unique tuple within the given
 251            range, use that.
 252
 253            This is only required for source (ie. NAT/masq) mappings.
 254            So far, we don't do local source mappings, so multiple
 255            manips not an issue.  */
 256         if (maniptype == IP_NAT_MANIP_SRC) {
 257                 if (find_appropriate_src(orig_tuple, tuple, range)) {
 258                         DEBUGP("get_unique_tuple: Found current src map\n");
 259                         if (!(range->flags & IP_NAT_RANGE_PROTO_RANDOM))
 260                                 if (!nf_nat_used_tuple(tuple, ct))
 261                                         return;
 262                 }
 263         }
 264
 265         /* 2) Select the least-used IP/proto combination in the given
 266            range. */
 267         *tuple = *orig_tuple;
 268         find_best_ips_proto(tuple, range, ct, maniptype);
 269
 270         /* 3) The per-protocol part of the manip is made to map into
 271            the range to make a unique tuple. */
 272
 273         rcu_read_lock();
 274         proto = __nf_nat_proto_find(orig_tuple->dst.protonum);
 275
 276         /* Change protocol info to have some randomization */
 277         if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) {
 278                 proto->unique_tuple(tuple, range, maniptype, ct);
 279                 goto out;
 280         }
 281
 282         /* Only bother mapping if it's not already in range and unique */
 283         if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
 284              proto->in_range(tuple, maniptype, &range->min, &range->max)) &&
 285             !nf_nat_used_tuple(tuple, ct))
 286                 goto out;
 287
 288         /* Last change: get protocol to try to obtain unique tuple. */
 289         proto->unique_tuple(tuple, range, maniptype, ct);
 290 out:
 291         rcu_read_unlock();
 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;
 301         struct nf_nat_info *info;
 302         int have_to_hash = !(ct->status & IPS_NAT_DONE_MASK);
 303         enum nf_nat_manip_type maniptype = HOOK2MANIP(hooknum);
 304
 305         /* nat helper or nfctnetlink also setup binding */
 306         nat = nfct_nat(ct);
 307         if (!nat) {
 308                 nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
 309                 if (nat == NULL) {
 310                         DEBUGP("failed to add NAT extension\n");
 311                         return NF_ACCEPT;
 312                 }
 313         }
 314
 315         NF_CT_ASSERT(hooknum == NF_IP_PRE_ROUTING ||
 316                      hooknum == NF_IP_POST_ROUTING ||
 317                      hooknum == NF_IP_LOCAL_IN ||
 318                      hooknum == NF_IP_LOCAL_OUT);
 319         BUG_ON(nf_nat_initialized(ct, maniptype));
 320
 321         /* What we've got will look like inverse of reply. Normally
 322            this is what is in the conntrack, except for prior
 323            manipulations (future optimization: if num_manips == 0,
 324            orig_tp =
 325            conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */
 326         nf_ct_invert_tuplepr(&curr_tuple,
 327                              &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 328
 329         get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
 330
 331         if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
 332                 struct nf_conntrack_tuple reply;
 333
 334                 /* Alter conntrack table so will recognize replies. */
 335                 nf_ct_invert_tuplepr(&reply, &new_tuple);
 336                 nf_conntrack_alter_reply(ct, &reply);
 337
 338                 /* Non-atomic: we own this at the moment. */
 339                 if (maniptype == IP_NAT_MANIP_SRC)
 340                         ct->status |= IPS_SRC_NAT;
 341                 else
 342                         ct->status |= IPS_DST_NAT;
 343         }
 344
 345         /* Place in source hash if this is the first time. */
 346         if (have_to_hash) {
 347                 unsigned int srchash;
 348
 349                 srchash = hash_by_src(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 350                 write_lock_bh(&nf_nat_lock);
 351                 /* nf_conntrack_alter_reply might re-allocate exntension aera */
 352                 info = &nfct_nat(ct)->info;
 353                 info->ct = ct;
 354                 list_add(&info->bysource, &bysource[srchash]);
 355                 write_unlock_bh(&nf_nat_lock);
 356         }
 357
 358         /* It's done. */
 359         if (maniptype == IP_NAT_MANIP_DST)
 360                 set_bit(IPS_DST_NAT_DONE_BIT, &ct->status);
 361         else
 362                 set_bit(IPS_SRC_NAT_DONE_BIT, &ct->status);
 363
 364         return NF_ACCEPT;
 365 }
 366 EXPORT_SYMBOL(nf_nat_setup_info);
 367
 368 /* Returns true if succeeded. */
 369 static int
 370 manip_pkt(u_int16_t proto,
 371           struct sk_buff **pskb,
 372           unsigned int iphdroff,
 373           const struct nf_conntrack_tuple *target,
 374           enum nf_nat_manip_type maniptype)
 375 {
 376         struct iphdr *iph;
 377         struct nf_nat_protocol *p;
 378
 379         if (!skb_make_writable(pskb, iphdroff + sizeof(*iph)))
 380                 return 0;
 381
 382         iph = (void *)(*pskb)->data + iphdroff;
 383
 384         /* Manipulate protcol part. */
 385
 386         /* rcu_read_lock()ed by nf_hook_slow */
 387         p = __nf_nat_proto_find(proto);
 388         if (!p->manip_pkt(pskb, iphdroff, target, maniptype))
 389                 return 0;
 390
 391         iph = (void *)(*pskb)->data + iphdroff;
 392
 393         if (maniptype == IP_NAT_MANIP_SRC) {
 394                 nf_csum_replace4(&iph->check, iph->saddr, target->src.u3.ip);
 395                 iph->saddr = target->src.u3.ip;
 396         } else {
 397                 nf_csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip);
 398                 iph->daddr = target->dst.u3.ip;
 399         }
 400         return 1;
 401 }
 402
 403 /* Do packet manipulations according to nf_nat_setup_info. */
 404 unsigned int nf_nat_packet(struct nf_conn *ct,
 405                            enum ip_conntrack_info ctinfo,
 406                            unsigned int hooknum,
 407                            struct sk_buff **pskb)
 408 {
 409         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 410         unsigned long statusbit;
 411         enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
 412
 413         if (mtype == IP_NAT_MANIP_SRC)
 414                 statusbit = IPS_SRC_NAT;
 415         else
 416                 statusbit = IPS_DST_NAT;
 417
 418         /* Invert if this is reply dir. */
 419         if (dir == IP_CT_DIR_REPLY)
 420                 statusbit ^= IPS_NAT_MASK;
 421
 422         /* Non-atomic: these bits don't change. */
 423         if (ct->status & statusbit) {
 424                 struct nf_conntrack_tuple target;
 425
 426                 /* We are aiming to look like inverse of other direction. */
 427                 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
 428
 429                 if (!manip_pkt(target.dst.protonum, pskb, 0, &target, mtype))
 430                         return NF_DROP;
 431         }
 432         return NF_ACCEPT;
 433 }
 434 EXPORT_SYMBOL_GPL(nf_nat_packet);
 435
 436 /* Dir is direction ICMP is coming from (opposite to packet it contains) */
 437 int nf_nat_icmp_reply_translation(struct nf_conn *ct,
 438                                   enum ip_conntrack_info ctinfo,
 439                                   unsigned int hooknum,
 440                                   struct sk_buff **pskb)
 441 {
 442         struct {
 443                 struct icmphdr icmp;
 444                 struct iphdr ip;
 445         } *inside;
 446         struct nf_conntrack_l4proto *l4proto;
 447         struct nf_conntrack_tuple inner, target;
 448         int hdrlen = ip_hdrlen(*pskb);
 449         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 450         unsigned long statusbit;
 451         enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
 452
 453         if (!skb_make_writable(pskb, hdrlen + sizeof(*inside)))
 454                 return 0;
 455
 456         inside = (void *)(*pskb)->data + ip_hdrlen(*pskb);
 457
 458         /* We're actually going to mangle it beyond trivial checksum
 459            adjustment, so make sure the current checksum is correct. */
 460         if (nf_ip_checksum(*pskb, hooknum, hdrlen, 0))
 461                 return 0;
 462
 463         /* Must be RELATED */
 464         NF_CT_ASSERT((*pskb)->nfctinfo == IP_CT_RELATED ||
 465                      (*pskb)->nfctinfo == IP_CT_RELATED+IP_CT_IS_REPLY);
 466
 467         /* Redirects on non-null nats must be dropped, else they'll
 468            start talking to each other without our translation, and be
 469            confused... --RR */
 470         if (inside->icmp.type == ICMP_REDIRECT) {
 471                 /* If NAT isn't finished, assume it and drop. */
 472                 if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
 473                         return 0;
 474
 475                 if (ct->status & IPS_NAT_MASK)
 476                         return 0;
 477         }
 478
 479         DEBUGP("icmp_reply_translation: translating error %p manp %u dir %s\n",
 480                *pskb, manip, dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY");
 481
 482         /* rcu_read_lock()ed by nf_hook_slow */
 483         l4proto = __nf_ct_l4proto_find(PF_INET, inside->ip.protocol);
 484
 485         if (!nf_ct_get_tuple(*pskb,
 486                              ip_hdrlen(*pskb) + sizeof(struct icmphdr),
 487                              (ip_hdrlen(*pskb) +
 488                               sizeof(struct icmphdr) + inside->ip.ihl * 4),
 489                              (u_int16_t)AF_INET,
 490                              inside->ip.protocol,
 491                              &inner, l3proto, l4proto))
 492                 return 0;
 493
 494         /* Change inner back to look like incoming packet.  We do the
 495            opposite manip on this hook to normal, because it might not
 496            pass all hooks (locally-generated ICMP).  Consider incoming
 497            packet: PREROUTING (DST manip), routing produces ICMP, goes
 498            through POSTROUTING (which must correct the DST manip). */
 499         if (!manip_pkt(inside->ip.protocol, pskb,
 500                        ip_hdrlen(*pskb) + sizeof(inside->icmp),
 501                        &ct->tuplehash[!dir].tuple,
 502                        !manip))
 503                 return 0;
 504
 505         if ((*pskb)->ip_summed != CHECKSUM_PARTIAL) {
 506                 /* Reloading "inside" here since manip_pkt inner. */
 507                 inside = (void *)(*pskb)->data + ip_hdrlen(*pskb);
 508                 inside->icmp.checksum = 0;
 509                 inside->icmp.checksum =
 510                         csum_fold(skb_checksum(*pskb, hdrlen,
 511                                                (*pskb)->len - hdrlen, 0));
 512         }
 513
 514         /* Change outer to look the reply to an incoming packet
 515          * (proto 0 means don't invert per-proto part). */
 516         if (manip == IP_NAT_MANIP_SRC)
 517                 statusbit = IPS_SRC_NAT;
 518         else
 519                 statusbit = IPS_DST_NAT;
 520
 521         /* Invert if this is reply dir. */
 522         if (dir == IP_CT_DIR_REPLY)
 523                 statusbit ^= IPS_NAT_MASK;
 524
 525         if (ct->status & statusbit) {
 526                 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
 527                 if (!manip_pkt(0, pskb, 0, &target, manip))
 528                         return 0;
 529         }
 530
 531         return 1;
 532 }
 533 EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation);
 534
 535 /* Protocol registration. */
 536 int nf_nat_protocol_register(struct nf_nat_protocol *proto)
 537 {
 538         int ret = 0;
 539
 540         write_lock_bh(&nf_nat_lock);
 541         if (nf_nat_protos[proto->protonum] != &nf_nat_unknown_protocol) {
 542                 ret = -EBUSY;
 543                 goto out;
 544         }
 545         rcu_assign_pointer(nf_nat_protos[proto->protonum], proto);
 546  out:
 547         write_unlock_bh(&nf_nat_lock);
 548         return ret;
 549 }
 550 EXPORT_SYMBOL(nf_nat_protocol_register);
 551
 552 /* Noone stores the protocol anywhere; simply delete it. */
 553 void nf_nat_protocol_unregister(struct nf_nat_protocol *proto)
 554 {
 555         write_lock_bh(&nf_nat_lock);
 556         rcu_assign_pointer(nf_nat_protos[proto->protonum],
 557                            &nf_nat_unknown_protocol);
 558         write_unlock_bh(&nf_nat_lock);
 559         synchronize_rcu();
 560 }
 561 EXPORT_SYMBOL(nf_nat_protocol_unregister);
 562
 563 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 564 int
 565 nf_nat_port_range_to_nfattr(struct sk_buff *skb,
 566                             const struct nf_nat_range *range)
 567 {
 568         NFA_PUT(skb, CTA_PROTONAT_PORT_MIN, sizeof(__be16),
 569                 &range->min.tcp.port);
 570         NFA_PUT(skb, CTA_PROTONAT_PORT_MAX, sizeof(__be16),
 571                 &range->max.tcp.port);
 572
 573         return 0;
 574
 575 nfattr_failure:
 576         return -1;
 577 }
 578 EXPORT_SYMBOL_GPL(nf_nat_port_nfattr_to_range);
 579
 580 int
 581 nf_nat_port_nfattr_to_range(struct nfattr *tb[], struct nf_nat_range *range)
 582 {
 583         int ret = 0;
 584
 585         /* we have to return whether we actually parsed something or not */
 586
 587         if (tb[CTA_PROTONAT_PORT_MIN-1]) {
 588                 ret = 1;
 589                 range->min.tcp.port =
 590                         *(__be16 *)NFA_DATA(tb[CTA_PROTONAT_PORT_MIN-1]);
 591         }
 592
 593         if (!tb[CTA_PROTONAT_PORT_MAX-1]) {
 594                 if (ret)
 595                         range->max.tcp.port = range->min.tcp.port;
 596         } else {
 597                 ret = 1;
 598                 range->max.tcp.port =
 599                         *(__be16 *)NFA_DATA(tb[CTA_PROTONAT_PORT_MAX-1]);
 600         }
 601
 602         return ret;
 603 }
 604 EXPORT_SYMBOL_GPL(nf_nat_port_range_to_nfattr);
 605 #endif
 606
 607 static void nf_nat_move_storage(struct nf_conn *conntrack, void *old)
 608 {
 609         struct nf_conn_nat *new_nat = nf_ct_ext_find(conntrack, NF_CT_EXT_NAT);
 610         struct nf_conn_nat *old_nat = (struct nf_conn_nat *)old;
 611         struct nf_conn *ct = old_nat->info.ct;
 612         unsigned int srchash;
 613
 614         if (!(ct->status & IPS_NAT_DONE_MASK))
 615                 return;
 616
 617         srchash = hash_by_src(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 618
 619         write_lock_bh(&nf_nat_lock);
 620         list_replace(&old_nat->info.bysource, &new_nat->info.bysource);
 621         new_nat->info.ct = ct;
 622         write_unlock_bh(&nf_nat_lock);
 623 }
 624
 625 struct nf_ct_ext_type nat_extend = {
 626         .len    = sizeof(struct nf_conn_nat),
 627         .align  = __alignof__(struct nf_conn_nat),
 628         .move   = nf_nat_move_storage,
 629         .id     = NF_CT_EXT_NAT,
 630         .flags  = NF_CT_EXT_F_PREALLOC,
 631 };
 632
 633 static int __init nf_nat_init(void)
 634 {
 635         size_t i;
 636         int ret;
 637
 638         ret = nf_ct_extend_register(&nat_extend);
 639         if (ret < 0) {
 640                 printk(KERN_ERR "nf_nat_core: Unable to register extension\n");
 641                 return ret;
 642         }
 643
 644         /* Leave them the same for the moment. */
 645         nf_nat_htable_size = nf_conntrack_htable_size;
 646
 647         /* One vmalloc for both hash tables */
 648         bysource = vmalloc(sizeof(struct list_head) * nf_nat_htable_size);
 649         if (!bysource) {
 650                 ret = -ENOMEM;
 651                 goto cleanup_extend;
 652         }
 653
 654         /* Sew in builtin protocols. */
 655         write_lock_bh(&nf_nat_lock);
 656         for (i = 0; i < MAX_IP_NAT_PROTO; i++)
 657                 rcu_assign_pointer(nf_nat_protos[i], &nf_nat_unknown_protocol);
 658         rcu_assign_pointer(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp);
 659         rcu_assign_pointer(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp);
 660         rcu_assign_pointer(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp);
 661         write_unlock_bh(&nf_nat_lock);
 662
 663         for (i = 0; i < nf_nat_htable_size; i++) {
 664                 INIT_LIST_HEAD(&bysource[i]);
 665         }
 666
 667         /* FIXME: Man, this is a hack.  <SIGH> */
 668         NF_CT_ASSERT(rcu_dereference(nf_conntrack_destroyed) == NULL);
 669         rcu_assign_pointer(nf_conntrack_destroyed, nf_nat_cleanup_conntrack);
 670
 671         /* Initialize fake conntrack so that NAT will skip it */
 672         nf_conntrack_untracked.status |= IPS_NAT_DONE_MASK;
 673
 674         l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET);
 675         return 0;
 676
 677  cleanup_extend:
 678         nf_ct_extend_unregister(&nat_extend);
 679         return ret;
 680 }
 681
 682 /* Clear NAT section of all conntracks, in case we're loaded again. */
 683 static int clean_nat(struct nf_conn *i, void *data)
 684 {
 685         struct nf_conn_nat *nat = nfct_nat(i);
 686
 687         if (!nat)
 688                 return 0;
 689         memset(nat, 0, sizeof(nat));
 690         i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST);
 691         return 0;
 692 }
 693
 694 static void __exit nf_nat_cleanup(void)
 695 {
 696         nf_ct_iterate_cleanup(&clean_nat, NULL);
 697         rcu_assign_pointer(nf_conntrack_destroyed, NULL);
 698         synchronize_rcu();
 699         vfree(bysource);
 700         nf_ct_l3proto_put(l3proto);
 701         nf_ct_extend_unregister(&nat_extend);
 702 }
 703
 704 MODULE_LICENSE("GPL");
 705
 706 module_init(nf_nat_init);
 707 module_exit(nf_nat_cleanup);