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 <net/checksum.h>
  16 #include <net/icmp.h>
  17 #include <net/ip.h>
  18 #include <net/tcp.h>  /* For tcp_prot in getorigdst */
  19 #include <linux/icmp.h>
  20 #include <linux/udp.h>
  21 #include <linux/jhash.h>
  22
  23 #include <linux/netfilter_ipv4.h>
  24 #include <net/netfilter/nf_conntrack.h>
  25 #include <net/netfilter/nf_conntrack_core.h>
  26 #include <net/netfilter/nf_nat.h>
  27 #include <net/netfilter/nf_nat_protocol.h>
  28 #include <net/netfilter/nf_nat_core.h>
  29 #include <net/netfilter/nf_nat_helper.h>
  30 #include <net/netfilter/nf_conntrack_helper.h>
  31 #include <net/netfilter/nf_conntrack_l3proto.h>
  32 #include <net/netfilter/nf_conntrack_l4proto.h>
  33
  34 static DEFINE_RWLOCK(nf_nat_lock);
  35
  36 static struct nf_conntrack_l3proto *l3proto = NULL;
  37
  38 /* Calculated at init based on memory size */
  39 static unsigned int nf_nat_htable_size;
  40 static int nf_nat_vmalloced;
  41
  42 static struct hlist_head *bysource;
  43
  44 #define MAX_IP_NAT_PROTO 256
  45 static struct nf_nat_protocol *nf_nat_protos[MAX_IP_NAT_PROTO];
  46
  47 static inline struct nf_nat_protocol *
  48 __nf_nat_proto_find(u_int8_t protonum)
  49 {
  50         return rcu_dereference(nf_nat_protos[protonum]);
  51 }
  52
  53 struct nf_nat_protocol *
  54 nf_nat_proto_find_get(u_int8_t protonum)
  55 {
  56         struct nf_nat_protocol *p;
  57
  58         rcu_read_lock();
  59         p = __nf_nat_proto_find(protonum);
  60         if (!try_module_get(p->me))
  61                 p = &nf_nat_unknown_protocol;
  62         rcu_read_unlock();
  63
  64         return p;
  65 }
  66 EXPORT_SYMBOL_GPL(nf_nat_proto_find_get);
  67
  68 void
  69 nf_nat_proto_put(struct nf_nat_protocol *p)
  70 {
  71         module_put(p->me);
  72 }
  73 EXPORT_SYMBOL_GPL(nf_nat_proto_put);
  74
  75 /* We keep an extra hash for each conntrack, for fast searching. */
  76 static inline unsigned int
  77 hash_by_src(const struct nf_conntrack_tuple *tuple)
  78 {
  79         /* Original src, to ensure we map it consistently if poss. */
  80         return jhash_3words((__force u32)tuple->src.u3.ip,
  81                             (__force u32)tuple->src.u.all,
  82                             tuple->dst.protonum, 0) % nf_nat_htable_size;
  83 }
  84
  85 /* Is this tuple already taken? (not by us) */
  86 int
  87 nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
  88                   const struct nf_conn *ignored_conntrack)
  89 {
  90         /* Conntrack tracking doesn't keep track of outgoing tuples; only
  91            incoming ones.  NAT means they don't have a fixed mapping,
  92            so we invert the tuple and look for the incoming reply.
  93
  94            We could keep a separate hash if this proves too slow. */
  95         struct nf_conntrack_tuple reply;
  96
  97         nf_ct_invert_tuplepr(&reply, tuple);
  98         return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
  99 }
 100 EXPORT_SYMBOL(nf_nat_used_tuple);
 101
 102 /* If we source map this tuple so reply looks like reply_tuple, will
 103  * that meet the constraints of range. */
 104 static int
 105 in_range(const struct nf_conntrack_tuple *tuple,
 106          const struct nf_nat_range *range)
 107 {
 108         struct nf_nat_protocol *proto;
 109         int ret = 0;
 110
 111         /* If we are supposed to map IPs, then we must be in the
 112            range specified, otherwise let this drag us onto a new src IP. */
 113         if (range->flags & IP_NAT_RANGE_MAP_IPS) {
 114                 if (ntohl(tuple->src.u3.ip) < ntohl(range->min_ip) ||
 115                     ntohl(tuple->src.u3.ip) > ntohl(range->max_ip))
 116                         return 0;
 117         }
 118
 119         rcu_read_lock();
 120         proto = __nf_nat_proto_find(tuple->dst.protonum);
 121         if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
 122             proto->in_range(tuple, IP_NAT_MANIP_SRC,
 123                             &range->min, &range->max))
 124                 ret = 1;
 125         rcu_read_unlock();
 126
 127         return ret;
 128 }
 129
 130 static inline int
 131 same_src(const struct nf_conn *ct,
 132          const struct nf_conntrack_tuple *tuple)
 133 {
 134         const struct nf_conntrack_tuple *t;
 135
 136         t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
 137         return (t->dst.protonum == tuple->dst.protonum &&
 138                 t->src.u3.ip == tuple->src.u3.ip &&
 139                 t->src.u.all == tuple->src.u.all);
 140 }
 141
 142 /* Only called for SRC manip */
 143 static int
 144 find_appropriate_src(const struct nf_conntrack_tuple *tuple,
 145                      struct nf_conntrack_tuple *result,
 146                      const struct nf_nat_range *range)
 147 {
 148         unsigned int h = hash_by_src(tuple);
 149         struct nf_conn_nat *nat;
 150         struct nf_conn *ct;
 151         struct hlist_node *n;
 152
 153         read_lock_bh(&nf_nat_lock);
 154         hlist_for_each_entry(nat, n, &bysource[h], bysource) {
 155                 ct = nat->ct;
 156                 if (same_src(ct, tuple)) {
 157                         /* Copy source part from reply tuple. */
 158                         nf_ct_invert_tuplepr(result,
 159                                        &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 160                         result->dst = tuple->dst;
 161
 162                         if (in_range(result, range)) {
 163                                 read_unlock_bh(&nf_nat_lock);
 164                                 return 1;
 165                         }
 166                 }
 167         }
 168         read_unlock_bh(&nf_nat_lock);
 169         return 0;
 170 }
 171
 172 /* For [FUTURE] fragmentation handling, we want the least-used
 173    src-ip/dst-ip/proto triple.  Fairness doesn't come into it.  Thus
 174    if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
 175    1-65535, we don't do pro-rata allocation based on ports; we choose
 176    the ip with the lowest src-ip/dst-ip/proto usage.
 177 */
 178 static void
 179 find_best_ips_proto(struct nf_conntrack_tuple *tuple,
 180                     const struct nf_nat_range *range,
 181                     const struct nf_conn *ct,
 182                     enum nf_nat_manip_type maniptype)
 183 {
 184         __be32 *var_ipp;
 185         /* Host order */
 186         u_int32_t minip, maxip, j;
 187
 188         /* No IP mapping?  Do nothing. */
 189         if (!(range->flags & IP_NAT_RANGE_MAP_IPS))
 190                 return;
 191
 192         if (maniptype == IP_NAT_MANIP_SRC)
 193                 var_ipp = &tuple->src.u3.ip;
 194         else
 195                 var_ipp = &tuple->dst.u3.ip;
 196
 197         /* Fast path: only one choice. */
 198         if (range->min_ip == range->max_ip) {
 199                 *var_ipp = range->min_ip;
 200                 return;
 201         }
 202
 203         /* Hashing source and destination IPs gives a fairly even
 204          * spread in practice (if there are a small number of IPs
 205          * involved, there usually aren't that many connections
 206          * anyway).  The consistency means that servers see the same
 207          * client coming from the same IP (some Internet Banking sites
 208          * like this), even across reboots. */
 209         minip = ntohl(range->min_ip);
 210         maxip = ntohl(range->max_ip);
 211         j = jhash_2words((__force u32)tuple->src.u3.ip,
 212                          (__force u32)tuple->dst.u3.ip, 0);
 213         *var_ipp = htonl(minip + j % (maxip - minip + 1));
 214 }
 215
 216 /* Manipulate the tuple into the range given.  For NF_IP_POST_ROUTING,
 217  * we change the source to map into the range.  For NF_IP_PRE_ROUTING
 218  * and NF_IP_LOCAL_OUT, we change the destination to map into the
 219  * range.  It might not be possible to get a unique tuple, but we try.
 220  * At worst (or if we race), we will end up with a final duplicate in
 221  * __ip_conntrack_confirm and drop the packet. */
 222 static void
 223 get_unique_tuple(struct nf_conntrack_tuple *tuple,
 224                  const struct nf_conntrack_tuple *orig_tuple,
 225                  const struct nf_nat_range *range,
 226                  struct nf_conn *ct,
 227                  enum nf_nat_manip_type maniptype)
 228 {
 229         struct nf_nat_protocol *proto;
 230
 231         /* 1) If this srcip/proto/src-proto-part is currently mapped,
 232            and that same mapping gives a unique tuple within the given
 233            range, use that.
 234
 235            This is only required for source (ie. NAT/masq) mappings.
 236            So far, we don't do local source mappings, so multiple
 237            manips not an issue.  */
 238         if (maniptype == IP_NAT_MANIP_SRC) {
 239                 if (find_appropriate_src(orig_tuple, tuple, range)) {
 240                         pr_debug("get_unique_tuple: Found current src map\n");
 241                         if (!(range->flags & IP_NAT_RANGE_PROTO_RANDOM))
 242                                 if (!nf_nat_used_tuple(tuple, ct))
 243                                         return;
 244                 }
 245         }
 246
 247         /* 2) Select the least-used IP/proto combination in the given
 248            range. */
 249         *tuple = *orig_tuple;
 250         find_best_ips_proto(tuple, range, ct, maniptype);
 251
 252         /* 3) The per-protocol part of the manip is made to map into
 253            the range to make a unique tuple. */
 254
 255         rcu_read_lock();
 256         proto = __nf_nat_proto_find(orig_tuple->dst.protonum);
 257
 258         /* Change protocol info to have some randomization */
 259         if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) {
 260                 proto->unique_tuple(tuple, range, maniptype, ct);
 261                 goto out;
 262         }
 263
 264         /* Only bother mapping if it's not already in range and unique */
 265         if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
 266              proto->in_range(tuple, maniptype, &range->min, &range->max)) &&
 267             !nf_nat_used_tuple(tuple, ct))
 268                 goto out;
 269
 270         /* Last change: get protocol to try to obtain unique tuple. */
 271         proto->unique_tuple(tuple, range, maniptype, ct);
 272 out:
 273         rcu_read_unlock();
 274 }
 275
 276 unsigned int
 277 nf_nat_setup_info(struct nf_conn *ct,
 278                   const struct nf_nat_range *range,
 279                   unsigned int hooknum)
 280 {
 281         struct nf_conntrack_tuple curr_tuple, new_tuple;
 282         struct nf_conn_nat *nat;
 283         int have_to_hash = !(ct->status & IPS_NAT_DONE_MASK);
 284         enum nf_nat_manip_type maniptype = HOOK2MANIP(hooknum);
 285
 286         /* nat helper or nfctnetlink also setup binding */
 287         nat = nfct_nat(ct);
 288         if (!nat) {
 289                 nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
 290                 if (nat == NULL) {
 291                         pr_debug("failed to add NAT extension\n");
 292                         return NF_ACCEPT;
 293                 }
 294         }
 295
 296         NF_CT_ASSERT(hooknum == NF_IP_PRE_ROUTING ||
 297                      hooknum == NF_IP_POST_ROUTING ||
 298                      hooknum == NF_IP_LOCAL_IN ||
 299                      hooknum == NF_IP_LOCAL_OUT);
 300         BUG_ON(nf_nat_initialized(ct, maniptype));
 301
 302         /* What we've got will look like inverse of reply. Normally
 303            this is what is in the conntrack, except for prior
 304            manipulations (future optimization: if num_manips == 0,
 305            orig_tp =
 306            conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */
 307         nf_ct_invert_tuplepr(&curr_tuple,
 308                              &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 309
 310         get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
 311
 312         if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
 313                 struct nf_conntrack_tuple reply;
 314
 315                 /* Alter conntrack table so will recognize replies. */
 316                 nf_ct_invert_tuplepr(&reply, &new_tuple);
 317                 nf_conntrack_alter_reply(ct, &reply);
 318
 319                 /* Non-atomic: we own this at the moment. */
 320                 if (maniptype == IP_NAT_MANIP_SRC)
 321                         ct->status |= IPS_SRC_NAT;
 322                 else
 323                         ct->status |= IPS_DST_NAT;
 324         }
 325
 326         /* Place in source hash if this is the first time. */
 327         if (have_to_hash) {
 328                 unsigned int srchash;
 329
 330                 srchash = hash_by_src(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 331                 write_lock_bh(&nf_nat_lock);
 332                 /* nf_conntrack_alter_reply might re-allocate exntension aera */
 333                 nat = nfct_nat(ct);
 334                 nat->ct = ct;
 335                 hlist_add_head(&nat->bysource, &bysource[srchash]);
 336                 write_unlock_bh(&nf_nat_lock);
 337         }
 338
 339         /* It's done. */
 340         if (maniptype == IP_NAT_MANIP_DST)
 341                 set_bit(IPS_DST_NAT_DONE_BIT, &ct->status);
 342         else
 343                 set_bit(IPS_SRC_NAT_DONE_BIT, &ct->status);
 344
 345         return NF_ACCEPT;
 346 }
 347 EXPORT_SYMBOL(nf_nat_setup_info);
 348
 349 /* Returns true if succeeded. */
 350 static int
 351 manip_pkt(u_int16_t proto,
 352           struct sk_buff **pskb,
 353           unsigned int iphdroff,
 354           const struct nf_conntrack_tuple *target,
 355           enum nf_nat_manip_type maniptype)
 356 {
 357         struct iphdr *iph;
 358         struct nf_nat_protocol *p;
 359
 360         if (!skb_make_writable(pskb, iphdroff + sizeof(*iph)))
 361                 return 0;
 362
 363         iph = (void *)(*pskb)->data + iphdroff;
 364
 365         /* Manipulate protcol part. */
 366
 367         /* rcu_read_lock()ed by nf_hook_slow */
 368         p = __nf_nat_proto_find(proto);
 369         if (!p->manip_pkt(pskb, iphdroff, target, maniptype))
 370                 return 0;
 371
 372         iph = (void *)(*pskb)->data + iphdroff;
 373
 374         if (maniptype == IP_NAT_MANIP_SRC) {
 375                 nf_csum_replace4(&iph->check, iph->saddr, target->src.u3.ip);
 376                 iph->saddr = target->src.u3.ip;
 377         } else {
 378                 nf_csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip);
 379                 iph->daddr = target->dst.u3.ip;
 380         }
 381         return 1;
 382 }
 383
 384 /* Do packet manipulations according to nf_nat_setup_info. */
 385 unsigned int nf_nat_packet(struct nf_conn *ct,
 386                            enum ip_conntrack_info ctinfo,
 387                            unsigned int hooknum,
 388                            struct sk_buff **pskb)
 389 {
 390         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 391         unsigned long statusbit;
 392         enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
 393
 394         if (mtype == IP_NAT_MANIP_SRC)
 395                 statusbit = IPS_SRC_NAT;
 396         else
 397                 statusbit = IPS_DST_NAT;
 398
 399         /* Invert if this is reply dir. */
 400         if (dir == IP_CT_DIR_REPLY)
 401                 statusbit ^= IPS_NAT_MASK;
 402
 403         /* Non-atomic: these bits don't change. */
 404         if (ct->status & statusbit) {
 405                 struct nf_conntrack_tuple target;
 406
 407                 /* We are aiming to look like inverse of other direction. */
 408                 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
 409
 410                 if (!manip_pkt(target.dst.protonum, pskb, 0, &target, mtype))
 411                         return NF_DROP;
 412         }
 413         return NF_ACCEPT;
 414 }
 415 EXPORT_SYMBOL_GPL(nf_nat_packet);
 416
 417 /* Dir is direction ICMP is coming from (opposite to packet it contains) */
 418 int nf_nat_icmp_reply_translation(struct nf_conn *ct,
 419                                   enum ip_conntrack_info ctinfo,
 420                                   unsigned int hooknum,
 421                                   struct sk_buff **pskb)
 422 {
 423         struct {
 424                 struct icmphdr icmp;
 425                 struct iphdr ip;
 426         } *inside;
 427         struct nf_conntrack_l4proto *l4proto;
 428         struct nf_conntrack_tuple inner, target;
 429         int hdrlen = ip_hdrlen(*pskb);
 430         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 431         unsigned long statusbit;
 432         enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
 433
 434         if (!skb_make_writable(pskb, hdrlen + sizeof(*inside)))
 435                 return 0;
 436
 437         inside = (void *)(*pskb)->data + ip_hdrlen(*pskb);
 438
 439         /* We're actually going to mangle it beyond trivial checksum
 440            adjustment, so make sure the current checksum is correct. */
 441         if (nf_ip_checksum(*pskb, hooknum, hdrlen, 0))
 442                 return 0;
 443
 444         /* Must be RELATED */
 445         NF_CT_ASSERT((*pskb)->nfctinfo == IP_CT_RELATED ||
 446                      (*pskb)->nfctinfo == IP_CT_RELATED+IP_CT_IS_REPLY);
 447
 448         /* Redirects on non-null nats must be dropped, else they'll
 449            start talking to each other without our translation, and be
 450            confused... --RR */
 451         if (inside->icmp.type == ICMP_REDIRECT) {
 452                 /* If NAT isn't finished, assume it and drop. */
 453                 if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
 454                         return 0;
 455
 456                 if (ct->status & IPS_NAT_MASK)
 457                         return 0;
 458         }
 459
 460         pr_debug("icmp_reply_translation: translating error %p manip %u "
 461                  "dir %s\n", *pskb, manip,
 462                  dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY");
 463
 464         /* rcu_read_lock()ed by nf_hook_slow */
 465         l4proto = __nf_ct_l4proto_find(PF_INET, inside->ip.protocol);
 466
 467         if (!nf_ct_get_tuple(*pskb,
 468                              ip_hdrlen(*pskb) + sizeof(struct icmphdr),
 469                              (ip_hdrlen(*pskb) +
 470                               sizeof(struct icmphdr) + inside->ip.ihl * 4),
 471                              (u_int16_t)AF_INET,
 472                              inside->ip.protocol,
 473                              &inner, l3proto, l4proto))
 474                 return 0;
 475
 476         /* Change inner back to look like incoming packet.  We do the
 477            opposite manip on this hook to normal, because it might not
 478            pass all hooks (locally-generated ICMP).  Consider incoming
 479            packet: PREROUTING (DST manip), routing produces ICMP, goes
 480            through POSTROUTING (which must correct the DST manip). */
 481         if (!manip_pkt(inside->ip.protocol, pskb,
 482                        ip_hdrlen(*pskb) + sizeof(inside->icmp),
 483                        &ct->tuplehash[!dir].tuple,
 484                        !manip))
 485                 return 0;
 486
 487         if ((*pskb)->ip_summed != CHECKSUM_PARTIAL) {
 488                 /* Reloading "inside" here since manip_pkt inner. */
 489                 inside = (void *)(*pskb)->data + ip_hdrlen(*pskb);
 490                 inside->icmp.checksum = 0;
 491                 inside->icmp.checksum =
 492                         csum_fold(skb_checksum(*pskb, hdrlen,
 493                                                (*pskb)->len - hdrlen, 0));
 494         }
 495
 496         /* Change outer to look the reply to an incoming packet
 497          * (proto 0 means don't invert per-proto part). */
 498         if (manip == IP_NAT_MANIP_SRC)
 499                 statusbit = IPS_SRC_NAT;
 500         else
 501                 statusbit = IPS_DST_NAT;
 502
 503         /* Invert if this is reply dir. */
 504         if (dir == IP_CT_DIR_REPLY)
 505                 statusbit ^= IPS_NAT_MASK;
 506
 507         if (ct->status & statusbit) {
 508                 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
 509                 if (!manip_pkt(0, pskb, 0, &target, manip))
 510                         return 0;
 511         }
 512
 513         return 1;
 514 }
 515 EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation);
 516
 517 /* Protocol registration. */
 518 int nf_nat_protocol_register(struct nf_nat_protocol *proto)
 519 {
 520         int ret = 0;
 521
 522         write_lock_bh(&nf_nat_lock);
 523         if (nf_nat_protos[proto->protonum] != &nf_nat_unknown_protocol) {
 524                 ret = -EBUSY;
 525                 goto out;
 526         }
 527         rcu_assign_pointer(nf_nat_protos[proto->protonum], proto);
 528  out:
 529         write_unlock_bh(&nf_nat_lock);
 530         return ret;
 531 }
 532 EXPORT_SYMBOL(nf_nat_protocol_register);
 533
 534 /* Noone stores the protocol anywhere; simply delete it. */
 535 void nf_nat_protocol_unregister(struct nf_nat_protocol *proto)
 536 {
 537         write_lock_bh(&nf_nat_lock);
 538         rcu_assign_pointer(nf_nat_protos[proto->protonum],
 539                            &nf_nat_unknown_protocol);
 540         write_unlock_bh(&nf_nat_lock);
 541         synchronize_rcu();
 542 }
 543 EXPORT_SYMBOL(nf_nat_protocol_unregister);
 544
 545 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 546 int
 547 nf_nat_port_range_to_nfattr(struct sk_buff *skb,
 548                             const struct nf_nat_range *range)
 549 {
 550         NFA_PUT(skb, CTA_PROTONAT_PORT_MIN, sizeof(__be16),
 551                 &range->min.tcp.port);
 552         NFA_PUT(skb, CTA_PROTONAT_PORT_MAX, sizeof(__be16),
 553                 &range->max.tcp.port);
 554
 555         return 0;
 556
 557 nfattr_failure:
 558         return -1;
 559 }
 560 EXPORT_SYMBOL_GPL(nf_nat_port_nfattr_to_range);
 561
 562 int
 563 nf_nat_port_nfattr_to_range(struct nfattr *tb[], struct nf_nat_range *range)
 564 {
 565         int ret = 0;
 566
 567         /* we have to return whether we actually parsed something or not */
 568
 569         if (tb[CTA_PROTONAT_PORT_MIN-1]) {
 570                 ret = 1;
 571                 range->min.tcp.port =
 572                         *(__be16 *)NFA_DATA(tb[CTA_PROTONAT_PORT_MIN-1]);
 573         }
 574
 575         if (!tb[CTA_PROTONAT_PORT_MAX-1]) {
 576                 if (ret)
 577                         range->max.tcp.port = range->min.tcp.port;
 578         } else {
 579                 ret = 1;
 580                 range->max.tcp.port =
 581                         *(__be16 *)NFA_DATA(tb[CTA_PROTONAT_PORT_MAX-1]);
 582         }
 583
 584         return ret;
 585 }
 586 EXPORT_SYMBOL_GPL(nf_nat_port_range_to_nfattr);
 587 #endif
 588
 589 /* Noone using conntrack by the time this called. */
 590 static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
 591 {
 592         struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT);
 593
 594         if (nat == NULL || nat->ct == NULL)
 595                 return;
 596
 597         NF_CT_ASSERT(nat->ct->status & IPS_NAT_DONE_MASK);
 598
 599         write_lock_bh(&nf_nat_lock);
 600         hlist_del(&nat->bysource);
 601         nat->ct = NULL;
 602         write_unlock_bh(&nf_nat_lock);
 603 }
 604
 605 static void nf_nat_move_storage(struct nf_conn *conntrack, void *old)
 606 {
 607         struct nf_conn_nat *new_nat = nf_ct_ext_find(conntrack, NF_CT_EXT_NAT);
 608         struct nf_conn_nat *old_nat = (struct nf_conn_nat *)old;
 609         struct nf_conn *ct = old_nat->ct;
 610         unsigned int srchash;
 611
 612         if (!(ct->status & IPS_NAT_DONE_MASK))
 613                 return;
 614
 615         srchash = hash_by_src(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 616
 617         write_lock_bh(&nf_nat_lock);
 618         hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource);
 619         new_nat->ct = ct;
 620         write_unlock_bh(&nf_nat_lock);
 621 }
 622
 623 static struct nf_ct_ext_type nat_extend __read_mostly = {
 624         .len            = sizeof(struct nf_conn_nat),
 625         .align          = __alignof__(struct nf_conn_nat),
 626         .destroy        = nf_nat_cleanup_conntrack,
 627         .move           = nf_nat_move_storage,
 628         .id             = NF_CT_EXT_NAT,
 629         .flags          = NF_CT_EXT_F_PREALLOC,
 630 };
 631
 632 static int __init nf_nat_init(void)
 633 {
 634         size_t i;
 635         int ret;
 636
 637         ret = nf_ct_extend_register(&nat_extend);
 638         if (ret < 0) {
 639                 printk(KERN_ERR "nf_nat_core: Unable to register extension\n");
 640                 return ret;
 641         }
 642
 643         /* Leave them the same for the moment. */
 644         nf_nat_htable_size = nf_conntrack_htable_size;
 645
 646         bysource = nf_ct_alloc_hashtable(&nf_nat_htable_size,
 647                                          &nf_nat_vmalloced);
 648         if (!bysource) {
 649                 ret = -ENOMEM;
 650                 goto cleanup_extend;
 651         }
 652
 653         /* Sew in builtin protocols. */
 654         write_lock_bh(&nf_nat_lock);
 655         for (i = 0; i < MAX_IP_NAT_PROTO; i++)
 656                 rcu_assign_pointer(nf_nat_protos[i], &nf_nat_unknown_protocol);
 657         rcu_assign_pointer(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp);
 658         rcu_assign_pointer(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp);
 659         rcu_assign_pointer(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp);
 660         write_unlock_bh(&nf_nat_lock);
 661
 662         for (i = 0; i < nf_nat_htable_size; i++) {
 663                 INIT_HLIST_HEAD(&bysource[i]);
 664         }
 665
 666         /* Initialize fake conntrack so that NAT will skip it */
 667         nf_conntrack_untracked.status |= IPS_NAT_DONE_MASK;
 668
 669         l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET);
 670         return 0;
 671
 672  cleanup_extend:
 673         nf_ct_extend_unregister(&nat_extend);
 674         return ret;
 675 }
 676
 677 /* Clear NAT section of all conntracks, in case we're loaded again. */
 678 static int clean_nat(struct nf_conn *i, void *data)
 679 {
 680         struct nf_conn_nat *nat = nfct_nat(i);
 681
 682         if (!nat)
 683                 return 0;
 684         memset(nat, 0, sizeof(nat));
 685         i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST);
 686         return 0;
 687 }
 688
 689 static void __exit nf_nat_cleanup(void)
 690 {
 691         nf_ct_iterate_cleanup(&clean_nat, NULL);
 692         synchronize_rcu();
 693         nf_ct_free_hashtable(bysource, nf_nat_vmalloced, nf_nat_htable_size);
 694         nf_ct_l3proto_put(l3proto);
 695         nf_ct_extend_unregister(&nat_extend);
 696 }
 697
 698 MODULE_LICENSE("GPL");
 699
 700 module_init(nf_nat_init);
 701 module_exit(nf_nat_cleanup);