Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
[linux-2.6.git] / 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/gfp.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_zones.h>
34
35 static DEFINE_SPINLOCK(nf_nat_lock);
36
37 static struct nf_conntrack_l3proto *l3proto __read_mostly;
38
39 #define MAX_IP_NAT_PROTO 256
40 static const struct nf_nat_protocol __rcu *nf_nat_protos[MAX_IP_NAT_PROTO]
41                                                 __read_mostly;
42
43 static inline const struct nf_nat_protocol *
44 __nf_nat_proto_find(u_int8_t protonum)
45 {
46         return rcu_dereference(nf_nat_protos[protonum]);
47 }
48
49 /* We keep an extra hash for each conntrack, for fast searching. */
50 static inline unsigned int
51 hash_by_src(const struct net *net, u16 zone,
52             const struct nf_conntrack_tuple *tuple)
53 {
54         unsigned int hash;
55
56         /* Original src, to ensure we map it consistently if poss. */
57         hash = jhash_3words((__force u32)tuple->src.u3.ip,
58                             (__force u32)tuple->src.u.all ^ zone,
59                             tuple->dst.protonum, nf_conntrack_hash_rnd);
60         return ((u64)hash * net->ipv4.nat_htable_size) >> 32;
61 }
62
63 /* Is this tuple already taken? (not by us) */
64 int
65 nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
66                   const struct nf_conn *ignored_conntrack)
67 {
68         /* Conntrack tracking doesn't keep track of outgoing tuples; only
69            incoming ones.  NAT means they don't have a fixed mapping,
70            so we invert the tuple and look for the incoming reply.
71
72            We could keep a separate hash if this proves too slow. */
73         struct nf_conntrack_tuple reply;
74
75         nf_ct_invert_tuplepr(&reply, tuple);
76         return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
77 }
78 EXPORT_SYMBOL(nf_nat_used_tuple);
79
80 /* If we source map this tuple so reply looks like reply_tuple, will
81  * that meet the constraints of range. */
82 static int
83 in_range(const struct nf_conntrack_tuple *tuple,
84          const struct nf_nat_ipv4_range *range)
85 {
86         const struct nf_nat_protocol *proto;
87         int ret = 0;
88
89         /* If we are supposed to map IPs, then we must be in the
90            range specified, otherwise let this drag us onto a new src IP. */
91         if (range->flags & NF_NAT_RANGE_MAP_IPS) {
92                 if (ntohl(tuple->src.u3.ip) < ntohl(range->min_ip) ||
93                     ntohl(tuple->src.u3.ip) > ntohl(range->max_ip))
94                         return 0;
95         }
96
97         rcu_read_lock();
98         proto = __nf_nat_proto_find(tuple->dst.protonum);
99         if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) ||
100             proto->in_range(tuple, NF_NAT_MANIP_SRC,
101                             &range->min, &range->max))
102                 ret = 1;
103         rcu_read_unlock();
104
105         return ret;
106 }
107
108 static inline int
109 same_src(const struct nf_conn *ct,
110          const struct nf_conntrack_tuple *tuple)
111 {
112         const struct nf_conntrack_tuple *t;
113
114         t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
115         return (t->dst.protonum == tuple->dst.protonum &&
116                 t->src.u3.ip == tuple->src.u3.ip &&
117                 t->src.u.all == tuple->src.u.all);
118 }
119
120 /* Only called for SRC manip */
121 static int
122 find_appropriate_src(struct net *net, u16 zone,
123                      const struct nf_conntrack_tuple *tuple,
124                      struct nf_conntrack_tuple *result,
125                      const struct nf_nat_ipv4_range *range)
126 {
127         unsigned int h = hash_by_src(net, zone, tuple);
128         const struct nf_conn_nat *nat;
129         const struct nf_conn *ct;
130         const struct hlist_node *n;
131
132         rcu_read_lock();
133         hlist_for_each_entry_rcu(nat, n, &net->ipv4.nat_bysource[h], bysource) {
134                 ct = nat->ct;
135                 if (same_src(ct, tuple) && nf_ct_zone(ct) == zone) {
136                         /* Copy source part from reply tuple. */
137                         nf_ct_invert_tuplepr(result,
138                                        &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
139                         result->dst = tuple->dst;
140
141                         if (in_range(result, range)) {
142                                 rcu_read_unlock();
143                                 return 1;
144                         }
145                 }
146         }
147         rcu_read_unlock();
148         return 0;
149 }
150
151 /* For [FUTURE] fragmentation handling, we want the least-used
152    src-ip/dst-ip/proto triple.  Fairness doesn't come into it.  Thus
153    if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
154    1-65535, we don't do pro-rata allocation based on ports; we choose
155    the ip with the lowest src-ip/dst-ip/proto usage.
156 */
157 static void
158 find_best_ips_proto(u16 zone, struct nf_conntrack_tuple *tuple,
159                     const struct nf_nat_ipv4_range *range,
160                     const struct nf_conn *ct,
161                     enum nf_nat_manip_type maniptype)
162 {
163         __be32 *var_ipp;
164         /* Host order */
165         u_int32_t minip, maxip, j;
166
167         /* No IP mapping?  Do nothing. */
168         if (!(range->flags & NF_NAT_RANGE_MAP_IPS))
169                 return;
170
171         if (maniptype == NF_NAT_MANIP_SRC)
172                 var_ipp = &tuple->src.u3.ip;
173         else
174                 var_ipp = &tuple->dst.u3.ip;
175
176         /* Fast path: only one choice. */
177         if (range->min_ip == range->max_ip) {
178                 *var_ipp = range->min_ip;
179                 return;
180         }
181
182         /* Hashing source and destination IPs gives a fairly even
183          * spread in practice (if there are a small number of IPs
184          * involved, there usually aren't that many connections
185          * anyway).  The consistency means that servers see the same
186          * client coming from the same IP (some Internet Banking sites
187          * like this), even across reboots. */
188         minip = ntohl(range->min_ip);
189         maxip = ntohl(range->max_ip);
190         j = jhash_2words((__force u32)tuple->src.u3.ip,
191                          range->flags & NF_NAT_RANGE_PERSISTENT ?
192                                 0 : (__force u32)tuple->dst.u3.ip ^ zone, 0);
193         j = ((u64)j * (maxip - minip + 1)) >> 32;
194         *var_ipp = htonl(minip + j);
195 }
196
197 /* Manipulate the tuple into the range given.  For NF_INET_POST_ROUTING,
198  * we change the source to map into the range.  For NF_INET_PRE_ROUTING
199  * and NF_INET_LOCAL_OUT, we change the destination to map into the
200  * range.  It might not be possible to get a unique tuple, but we try.
201  * At worst (or if we race), we will end up with a final duplicate in
202  * __ip_conntrack_confirm and drop the packet. */
203 static void
204 get_unique_tuple(struct nf_conntrack_tuple *tuple,
205                  const struct nf_conntrack_tuple *orig_tuple,
206                  const struct nf_nat_ipv4_range *range,
207                  struct nf_conn *ct,
208                  enum nf_nat_manip_type maniptype)
209 {
210         struct net *net = nf_ct_net(ct);
211         const struct nf_nat_protocol *proto;
212         u16 zone = nf_ct_zone(ct);
213
214         /* 1) If this srcip/proto/src-proto-part is currently mapped,
215            and that same mapping gives a unique tuple within the given
216            range, use that.
217
218            This is only required for source (ie. NAT/masq) mappings.
219            So far, we don't do local source mappings, so multiple
220            manips not an issue.  */
221         if (maniptype == NF_NAT_MANIP_SRC &&
222             !(range->flags & NF_NAT_RANGE_PROTO_RANDOM)) {
223                 /* try the original tuple first */
224                 if (in_range(orig_tuple, range)) {
225                         if (!nf_nat_used_tuple(orig_tuple, ct)) {
226                                 *tuple = *orig_tuple;
227                                 return;
228                         }
229                 } else if (find_appropriate_src(net, zone, orig_tuple, tuple,
230                            range)) {
231                         pr_debug("get_unique_tuple: Found current src map\n");
232                         if (!nf_nat_used_tuple(tuple, ct))
233                                 return;
234                 }
235         }
236
237         /* 2) Select the least-used IP/proto combination in the given
238            range. */
239         *tuple = *orig_tuple;
240         find_best_ips_proto(zone, tuple, range, ct, maniptype);
241
242         /* 3) The per-protocol part of the manip is made to map into
243            the range to make a unique tuple. */
244
245         rcu_read_lock();
246         proto = __nf_nat_proto_find(orig_tuple->dst.protonum);
247
248         /* Only bother mapping if it's not already in range and unique */
249         if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM)) {
250                 if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
251                         if (proto->in_range(tuple, maniptype, &range->min,
252                                             &range->max) &&
253                             (range->min.all == range->max.all ||
254                              !nf_nat_used_tuple(tuple, ct)))
255                                 goto out;
256                 } else if (!nf_nat_used_tuple(tuple, ct)) {
257                         goto out;
258                 }
259         }
260
261         /* Last change: get protocol to try to obtain unique tuple. */
262         proto->unique_tuple(tuple, range, maniptype, ct);
263 out:
264         rcu_read_unlock();
265 }
266
267 unsigned int
268 nf_nat_setup_info(struct nf_conn *ct,
269                   const struct nf_nat_ipv4_range *range,
270                   enum nf_nat_manip_type maniptype)
271 {
272         struct net *net = nf_ct_net(ct);
273         struct nf_conntrack_tuple curr_tuple, new_tuple;
274         struct nf_conn_nat *nat;
275
276         /* nat helper or nfctnetlink also setup binding */
277         nat = nfct_nat(ct);
278         if (!nat) {
279                 nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
280                 if (nat == NULL) {
281                         pr_debug("failed to add NAT extension\n");
282                         return NF_ACCEPT;
283                 }
284         }
285
286         NF_CT_ASSERT(maniptype == NF_NAT_MANIP_SRC ||
287                      maniptype == NF_NAT_MANIP_DST);
288         BUG_ON(nf_nat_initialized(ct, maniptype));
289
290         /* What we've got will look like inverse of reply. Normally
291            this is what is in the conntrack, except for prior
292            manipulations (future optimization: if num_manips == 0,
293            orig_tp =
294            conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */
295         nf_ct_invert_tuplepr(&curr_tuple,
296                              &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
297
298         get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
299
300         if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
301                 struct nf_conntrack_tuple reply;
302
303                 /* Alter conntrack table so will recognize replies. */
304                 nf_ct_invert_tuplepr(&reply, &new_tuple);
305                 nf_conntrack_alter_reply(ct, &reply);
306
307                 /* Non-atomic: we own this at the moment. */
308                 if (maniptype == NF_NAT_MANIP_SRC)
309                         ct->status |= IPS_SRC_NAT;
310                 else
311                         ct->status |= IPS_DST_NAT;
312         }
313
314         if (maniptype == NF_NAT_MANIP_SRC) {
315                 unsigned int srchash;
316
317                 srchash = hash_by_src(net, nf_ct_zone(ct),
318                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
319                 spin_lock_bh(&nf_nat_lock);
320                 /* nf_conntrack_alter_reply might re-allocate extension area */
321                 nat = nfct_nat(ct);
322                 nat->ct = ct;
323                 hlist_add_head_rcu(&nat->bysource,
324                                    &net->ipv4.nat_bysource[srchash]);
325                 spin_unlock_bh(&nf_nat_lock);
326         }
327
328         /* It's done. */
329         if (maniptype == NF_NAT_MANIP_DST)
330                 ct->status |= IPS_DST_NAT_DONE;
331         else
332                 ct->status |= IPS_SRC_NAT_DONE;
333
334         return NF_ACCEPT;
335 }
336 EXPORT_SYMBOL(nf_nat_setup_info);
337
338 /* Returns true if succeeded. */
339 static bool
340 manip_pkt(u_int16_t proto,
341           struct sk_buff *skb,
342           unsigned int iphdroff,
343           const struct nf_conntrack_tuple *target,
344           enum nf_nat_manip_type maniptype)
345 {
346         struct iphdr *iph;
347         const struct nf_nat_protocol *p;
348
349         if (!skb_make_writable(skb, iphdroff + sizeof(*iph)))
350                 return false;
351
352         iph = (void *)skb->data + iphdroff;
353
354         /* Manipulate protcol part. */
355
356         /* rcu_read_lock()ed by nf_hook_slow */
357         p = __nf_nat_proto_find(proto);
358         if (!p->manip_pkt(skb, iphdroff, target, maniptype))
359                 return false;
360
361         iph = (void *)skb->data + iphdroff;
362
363         if (maniptype == NF_NAT_MANIP_SRC) {
364                 csum_replace4(&iph->check, iph->saddr, target->src.u3.ip);
365                 iph->saddr = target->src.u3.ip;
366         } else {
367                 csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip);
368                 iph->daddr = target->dst.u3.ip;
369         }
370         return true;
371 }
372
373 /* Do packet manipulations according to nf_nat_setup_info. */
374 unsigned int nf_nat_packet(struct nf_conn *ct,
375                            enum ip_conntrack_info ctinfo,
376                            unsigned int hooknum,
377                            struct sk_buff *skb)
378 {
379         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
380         unsigned long statusbit;
381         enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
382
383         if (mtype == NF_NAT_MANIP_SRC)
384                 statusbit = IPS_SRC_NAT;
385         else
386                 statusbit = IPS_DST_NAT;
387
388         /* Invert if this is reply dir. */
389         if (dir == IP_CT_DIR_REPLY)
390                 statusbit ^= IPS_NAT_MASK;
391
392         /* Non-atomic: these bits don't change. */
393         if (ct->status & statusbit) {
394                 struct nf_conntrack_tuple target;
395
396                 /* We are aiming to look like inverse of other direction. */
397                 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
398
399                 if (!manip_pkt(target.dst.protonum, skb, 0, &target, mtype))
400                         return NF_DROP;
401         }
402         return NF_ACCEPT;
403 }
404 EXPORT_SYMBOL_GPL(nf_nat_packet);
405
406 /* Dir is direction ICMP is coming from (opposite to packet it contains) */
407 int nf_nat_icmp_reply_translation(struct nf_conn *ct,
408                                   enum ip_conntrack_info ctinfo,
409                                   unsigned int hooknum,
410                                   struct sk_buff *skb)
411 {
412         struct {
413                 struct icmphdr icmp;
414                 struct iphdr ip;
415         } *inside;
416         struct nf_conntrack_tuple target;
417         int hdrlen = ip_hdrlen(skb);
418         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
419         unsigned long statusbit;
420         enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
421
422         if (!skb_make_writable(skb, hdrlen + sizeof(*inside)))
423                 return 0;
424
425         inside = (void *)skb->data + hdrlen;
426
427         /* We're actually going to mangle it beyond trivial checksum
428            adjustment, so make sure the current checksum is correct. */
429         if (nf_ip_checksum(skb, hooknum, hdrlen, 0))
430                 return 0;
431
432         /* Must be RELATED */
433         NF_CT_ASSERT(skb->nfctinfo == IP_CT_RELATED ||
434                      skb->nfctinfo == IP_CT_RELATED_REPLY);
435
436         /* Redirects on non-null nats must be dropped, else they'll
437            start talking to each other without our translation, and be
438            confused... --RR */
439         if (inside->icmp.type == ICMP_REDIRECT) {
440                 /* If NAT isn't finished, assume it and drop. */
441                 if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
442                         return 0;
443
444                 if (ct->status & IPS_NAT_MASK)
445                         return 0;
446         }
447
448         if (manip == NF_NAT_MANIP_SRC)
449                 statusbit = IPS_SRC_NAT;
450         else
451                 statusbit = IPS_DST_NAT;
452
453         /* Invert if this is reply dir. */
454         if (dir == IP_CT_DIR_REPLY)
455                 statusbit ^= IPS_NAT_MASK;
456
457         if (!(ct->status & statusbit))
458                 return 1;
459
460         pr_debug("icmp_reply_translation: translating error %p manip %u "
461                  "dir %s\n", skb, manip,
462                  dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY");
463
464         /* Change inner back to look like incoming packet.  We do the
465            opposite manip on this hook to normal, because it might not
466            pass all hooks (locally-generated ICMP).  Consider incoming
467            packet: PREROUTING (DST manip), routing produces ICMP, goes
468            through POSTROUTING (which must correct the DST manip). */
469         if (!manip_pkt(inside->ip.protocol, skb, hdrlen + sizeof(inside->icmp),
470                        &ct->tuplehash[!dir].tuple, !manip))
471                 return 0;
472
473         if (skb->ip_summed != CHECKSUM_PARTIAL) {
474                 /* Reloading "inside" here since manip_pkt inner. */
475                 inside = (void *)skb->data + hdrlen;
476                 inside->icmp.checksum = 0;
477                 inside->icmp.checksum =
478                         csum_fold(skb_checksum(skb, hdrlen,
479                                                skb->len - hdrlen, 0));
480         }
481
482         /* Change outer to look the reply to an incoming packet
483          * (proto 0 means don't invert per-proto part). */
484         nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
485         if (!manip_pkt(0, skb, 0, &target, manip))
486                 return 0;
487
488         return 1;
489 }
490 EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation);
491
492 /* Protocol registration. */
493 int nf_nat_protocol_register(const struct nf_nat_protocol *proto)
494 {
495         int ret = 0;
496
497         spin_lock_bh(&nf_nat_lock);
498         if (rcu_dereference_protected(
499                         nf_nat_protos[proto->protonum],
500                         lockdep_is_held(&nf_nat_lock)
501                         ) != &nf_nat_unknown_protocol) {
502                 ret = -EBUSY;
503                 goto out;
504         }
505         RCU_INIT_POINTER(nf_nat_protos[proto->protonum], proto);
506  out:
507         spin_unlock_bh(&nf_nat_lock);
508         return ret;
509 }
510 EXPORT_SYMBOL(nf_nat_protocol_register);
511
512 /* No one stores the protocol anywhere; simply delete it. */
513 void nf_nat_protocol_unregister(const struct nf_nat_protocol *proto)
514 {
515         spin_lock_bh(&nf_nat_lock);
516         RCU_INIT_POINTER(nf_nat_protos[proto->protonum],
517                            &nf_nat_unknown_protocol);
518         spin_unlock_bh(&nf_nat_lock);
519         synchronize_rcu();
520 }
521 EXPORT_SYMBOL(nf_nat_protocol_unregister);
522
523 /* No one using conntrack by the time this called. */
524 static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
525 {
526         struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT);
527
528         if (nat == NULL || nat->ct == NULL)
529                 return;
530
531         NF_CT_ASSERT(nat->ct->status & IPS_SRC_NAT_DONE);
532
533         spin_lock_bh(&nf_nat_lock);
534         hlist_del_rcu(&nat->bysource);
535         spin_unlock_bh(&nf_nat_lock);
536 }
537
538 static void nf_nat_move_storage(void *new, void *old)
539 {
540         struct nf_conn_nat *new_nat = new;
541         struct nf_conn_nat *old_nat = old;
542         struct nf_conn *ct = old_nat->ct;
543
544         if (!ct || !(ct->status & IPS_SRC_NAT_DONE))
545                 return;
546
547         spin_lock_bh(&nf_nat_lock);
548         hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource);
549         spin_unlock_bh(&nf_nat_lock);
550 }
551
552 static struct nf_ct_ext_type nat_extend __read_mostly = {
553         .len            = sizeof(struct nf_conn_nat),
554         .align          = __alignof__(struct nf_conn_nat),
555         .destroy        = nf_nat_cleanup_conntrack,
556         .move           = nf_nat_move_storage,
557         .id             = NF_CT_EXT_NAT,
558         .flags          = NF_CT_EXT_F_PREALLOC,
559 };
560
561 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
562
563 #include <linux/netfilter/nfnetlink.h>
564 #include <linux/netfilter/nfnetlink_conntrack.h>
565
566 static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = {
567         [CTA_PROTONAT_PORT_MIN] = { .type = NLA_U16 },
568         [CTA_PROTONAT_PORT_MAX] = { .type = NLA_U16 },
569 };
570
571 static int nfnetlink_parse_nat_proto(struct nlattr *attr,
572                                      const struct nf_conn *ct,
573                                      struct nf_nat_ipv4_range *range)
574 {
575         struct nlattr *tb[CTA_PROTONAT_MAX+1];
576         const struct nf_nat_protocol *npt;
577         int err;
578
579         err = nla_parse_nested(tb, CTA_PROTONAT_MAX, attr, protonat_nla_policy);
580         if (err < 0)
581                 return err;
582
583         rcu_read_lock();
584         npt = __nf_nat_proto_find(nf_ct_protonum(ct));
585         if (npt->nlattr_to_range)
586                 err = npt->nlattr_to_range(tb, range);
587         rcu_read_unlock();
588         return err;
589 }
590
591 static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
592         [CTA_NAT_MINIP]         = { .type = NLA_U32 },
593         [CTA_NAT_MAXIP]         = { .type = NLA_U32 },
594         [CTA_NAT_PROTO]         = { .type = NLA_NESTED },
595 };
596
597 static int
598 nfnetlink_parse_nat(const struct nlattr *nat,
599                     const struct nf_conn *ct, struct nf_nat_ipv4_range *range)
600 {
601         struct nlattr *tb[CTA_NAT_MAX+1];
602         int err;
603
604         memset(range, 0, sizeof(*range));
605
606         err = nla_parse_nested(tb, CTA_NAT_MAX, nat, nat_nla_policy);
607         if (err < 0)
608                 return err;
609
610         if (tb[CTA_NAT_MINIP])
611                 range->min_ip = nla_get_be32(tb[CTA_NAT_MINIP]);
612
613         if (!tb[CTA_NAT_MAXIP])
614                 range->max_ip = range->min_ip;
615         else
616                 range->max_ip = nla_get_be32(tb[CTA_NAT_MAXIP]);
617
618         if (range->min_ip)
619                 range->flags |= NF_NAT_RANGE_MAP_IPS;
620
621         if (!tb[CTA_NAT_PROTO])
622                 return 0;
623
624         err = nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range);
625         if (err < 0)
626                 return err;
627
628         return 0;
629 }
630
631 static int
632 nfnetlink_parse_nat_setup(struct nf_conn *ct,
633                           enum nf_nat_manip_type manip,
634                           const struct nlattr *attr)
635 {
636         struct nf_nat_ipv4_range range;
637
638         if (nfnetlink_parse_nat(attr, ct, &range) < 0)
639                 return -EINVAL;
640         if (nf_nat_initialized(ct, manip))
641                 return -EEXIST;
642
643         return nf_nat_setup_info(ct, &range, manip);
644 }
645 #else
646 static int
647 nfnetlink_parse_nat_setup(struct nf_conn *ct,
648                           enum nf_nat_manip_type manip,
649                           const struct nlattr *attr)
650 {
651         return -EOPNOTSUPP;
652 }
653 #endif
654
655 static int __net_init nf_nat_net_init(struct net *net)
656 {
657         /* Leave them the same for the moment. */
658         net->ipv4.nat_htable_size = net->ct.htable_size;
659         net->ipv4.nat_bysource = nf_ct_alloc_hashtable(&net->ipv4.nat_htable_size, 0);
660         if (!net->ipv4.nat_bysource)
661                 return -ENOMEM;
662         return 0;
663 }
664
665 /* Clear NAT section of all conntracks, in case we're loaded again. */
666 static int clean_nat(struct nf_conn *i, void *data)
667 {
668         struct nf_conn_nat *nat = nfct_nat(i);
669
670         if (!nat)
671                 return 0;
672         memset(nat, 0, sizeof(*nat));
673         i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST);
674         return 0;
675 }
676
677 static void __net_exit nf_nat_net_exit(struct net *net)
678 {
679         nf_ct_iterate_cleanup(net, &clean_nat, NULL);
680         synchronize_rcu();
681         nf_ct_free_hashtable(net->ipv4.nat_bysource, net->ipv4.nat_htable_size);
682 }
683
684 static struct pernet_operations nf_nat_net_ops = {
685         .init = nf_nat_net_init,
686         .exit = nf_nat_net_exit,
687 };
688
689 static int __init nf_nat_init(void)
690 {
691         size_t i;
692         int ret;
693
694         need_ipv4_conntrack();
695
696         ret = nf_ct_extend_register(&nat_extend);
697         if (ret < 0) {
698                 printk(KERN_ERR "nf_nat_core: Unable to register extension\n");
699                 return ret;
700         }
701
702         ret = register_pernet_subsys(&nf_nat_net_ops);
703         if (ret < 0)
704                 goto cleanup_extend;
705
706         /* Sew in builtin protocols. */
707         spin_lock_bh(&nf_nat_lock);
708         for (i = 0; i < MAX_IP_NAT_PROTO; i++)
709                 RCU_INIT_POINTER(nf_nat_protos[i], &nf_nat_unknown_protocol);
710         RCU_INIT_POINTER(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp);
711         RCU_INIT_POINTER(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp);
712         RCU_INIT_POINTER(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp);
713         spin_unlock_bh(&nf_nat_lock);
714
715         /* Initialize fake conntrack so that NAT will skip it */
716         nf_ct_untracked_status_or(IPS_NAT_DONE_MASK);
717
718         l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET);
719
720         BUG_ON(nf_nat_seq_adjust_hook != NULL);
721         RCU_INIT_POINTER(nf_nat_seq_adjust_hook, nf_nat_seq_adjust);
722         BUG_ON(nfnetlink_parse_nat_setup_hook != NULL);
723         RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook,
724                            nfnetlink_parse_nat_setup);
725         BUG_ON(nf_ct_nat_offset != NULL);
726         RCU_INIT_POINTER(nf_ct_nat_offset, nf_nat_get_offset);
727         return 0;
728
729  cleanup_extend:
730         nf_ct_extend_unregister(&nat_extend);
731         return ret;
732 }
733
734 static void __exit nf_nat_cleanup(void)
735 {
736         unregister_pernet_subsys(&nf_nat_net_ops);
737         nf_ct_l3proto_put(l3proto);
738         nf_ct_extend_unregister(&nat_extend);
739         RCU_INIT_POINTER(nf_nat_seq_adjust_hook, NULL);
740         RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook, NULL);
741         RCU_INIT_POINTER(nf_ct_nat_offset, NULL);
742         synchronize_net();
743 }
744
745 MODULE_LICENSE("GPL");
746 MODULE_ALIAS("nf-nat-ipv4");
747
748 module_init(nf_nat_init);
749 module_exit(nf_nat_cleanup);