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netfilter: nf_nat: fix compiler warning with CONFIG_NF_CT_NETLINK=n
[net-next-2.6.git] / net / ipv4 / netfilter / nf_nat_core.c
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CommitLineData
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_l4proto.h>
34#include <net/netfilter/nf_conntrack_zones.h>
35
36static DEFINE_SPINLOCK(nf_nat_lock);
37
38static struct nf_conntrack_l3proto *l3proto __read_mostly;
39
40#define MAX_IP_NAT_PROTO 256
41static const struct nf_nat_protocol __rcu *nf_nat_protos[MAX_IP_NAT_PROTO]
42 __read_mostly;
43
44static inline const struct nf_nat_protocol *
45__nf_nat_proto_find(u_int8_t protonum)
46{
47 return rcu_dereference(nf_nat_protos[protonum]);
48}
49
50/* We keep an extra hash for each conntrack, for fast searching. */
51static inline unsigned int
52hash_by_src(const struct net *net, u16 zone,
53 const struct nf_conntrack_tuple *tuple)
54{
55 unsigned int hash;
56
57 /* Original src, to ensure we map it consistently if poss. */
58 hash = jhash_3words((__force u32)tuple->src.u3.ip,
59 (__force u32)tuple->src.u.all ^ zone,
60 tuple->dst.protonum, 0);
61 return ((u64)hash * net->ipv4.nat_htable_size) >> 32;
62}
63
64/* Is this tuple already taken? (not by us) */
65int
66nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
67 const struct nf_conn *ignored_conntrack)
68{
69 /* Conntrack tracking doesn't keep track of outgoing tuples; only
70 incoming ones. NAT means they don't have a fixed mapping,
71 so we invert the tuple and look for the incoming reply.
72
73 We could keep a separate hash if this proves too slow. */
74 struct nf_conntrack_tuple reply;
75
76 nf_ct_invert_tuplepr(&reply, tuple);
77 return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
78}
79EXPORT_SYMBOL(nf_nat_used_tuple);
80
81/* If we source map this tuple so reply looks like reply_tuple, will
82 * that meet the constraints of range. */
83static int
84in_range(const struct nf_conntrack_tuple *tuple,
85 const struct nf_nat_range *range)
86{
87 const struct nf_nat_protocol *proto;
88 int ret = 0;
89
90 /* If we are supposed to map IPs, then we must be in the
91 range specified, otherwise let this drag us onto a new src IP. */
92 if (range->flags & IP_NAT_RANGE_MAP_IPS) {
93 if (ntohl(tuple->src.u3.ip) < ntohl(range->min_ip) ||
94 ntohl(tuple->src.u3.ip) > ntohl(range->max_ip))
95 return 0;
96 }
97
98 rcu_read_lock();
99 proto = __nf_nat_proto_find(tuple->dst.protonum);
100 if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
101 proto->in_range(tuple, IP_NAT_MANIP_SRC,
102 &range->min, &range->max))
103 ret = 1;
104 rcu_read_unlock();
105
106 return ret;
107}
108
109static inline int
110same_src(const struct nf_conn *ct,
111 const struct nf_conntrack_tuple *tuple)
112{
113 const struct nf_conntrack_tuple *t;
114
115 t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
116 return (t->dst.protonum == tuple->dst.protonum &&
117 t->src.u3.ip == tuple->src.u3.ip &&
118 t->src.u.all == tuple->src.u.all);
119}
120
121/* Only called for SRC manip */
122static int
123find_appropriate_src(struct net *net, u16 zone,
124 const struct nf_conntrack_tuple *tuple,
125 struct nf_conntrack_tuple *result,
126 const struct nf_nat_range *range)
127{
128 unsigned int h = hash_by_src(net, zone, tuple);
129 const struct nf_conn_nat *nat;
130 const struct nf_conn *ct;
131 const struct hlist_node *n;
132
133 rcu_read_lock();
134 hlist_for_each_entry_rcu(nat, n, &net->ipv4.nat_bysource[h], bysource) {
135 ct = nat->ct;
136 if (same_src(ct, tuple) && nf_ct_zone(ct) == zone) {
137 /* Copy source part from reply tuple. */
138 nf_ct_invert_tuplepr(result,
139 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
140 result->dst = tuple->dst;
141
142 if (in_range(result, range)) {
143 rcu_read_unlock();
144 return 1;
145 }
146 }
147 }
148 rcu_read_unlock();
149 return 0;
150}
151
152/* For [FUTURE] fragmentation handling, we want the least-used
153 src-ip/dst-ip/proto triple. Fairness doesn't come into it. Thus
154 if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
155 1-65535, we don't do pro-rata allocation based on ports; we choose
156 the ip with the lowest src-ip/dst-ip/proto usage.
157*/
158static void
159find_best_ips_proto(u16 zone, struct nf_conntrack_tuple *tuple,
160 const struct nf_nat_range *range,
161 const struct nf_conn *ct,
162 enum nf_nat_manip_type maniptype)
163{
164 __be32 *var_ipp;
165 /* Host order */
166 u_int32_t minip, maxip, j;
167
168 /* No IP mapping? Do nothing. */
169 if (!(range->flags & IP_NAT_RANGE_MAP_IPS))
170 return;
171
172 if (maniptype == IP_NAT_MANIP_SRC)
173 var_ipp = &tuple->src.u3.ip;
174 else
175 var_ipp = &tuple->dst.u3.ip;
176
177 /* Fast path: only one choice. */
178 if (range->min_ip == range->max_ip) {
179 *var_ipp = range->min_ip;
180 return;
181 }
182
183 /* Hashing source and destination IPs gives a fairly even
184 * spread in practice (if there are a small number of IPs
185 * involved, there usually aren't that many connections
186 * anyway). The consistency means that servers see the same
187 * client coming from the same IP (some Internet Banking sites
188 * like this), even across reboots. */
189 minip = ntohl(range->min_ip);
190 maxip = ntohl(range->max_ip);
191 j = jhash_2words((__force u32)tuple->src.u3.ip,
192 range->flags & IP_NAT_RANGE_PERSISTENT ?
193 0 : (__force u32)tuple->dst.u3.ip ^ zone, 0);
194 j = ((u64)j * (maxip - minip + 1)) >> 32;
195 *var_ipp = htonl(minip + j);
196}
197
198/* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING,
199 * we change the source to map into the range. For NF_INET_PRE_ROUTING
200 * and NF_INET_LOCAL_OUT, we change the destination to map into the
201 * range. It might not be possible to get a unique tuple, but we try.
202 * At worst (or if we race), we will end up with a final duplicate in
203 * __ip_conntrack_confirm and drop the packet. */
204static void
205get_unique_tuple(struct nf_conntrack_tuple *tuple,
206 const struct nf_conntrack_tuple *orig_tuple,
207 const struct nf_nat_range *range,
208 struct nf_conn *ct,
209 enum nf_nat_manip_type maniptype)
210{
211 struct net *net = nf_ct_net(ct);
212 const struct nf_nat_protocol *proto;
213 u16 zone = nf_ct_zone(ct);
214
215 /* 1) If this srcip/proto/src-proto-part is currently mapped,
216 and that same mapping gives a unique tuple within the given
217 range, use that.
218
219 This is only required for source (ie. NAT/masq) mappings.
220 So far, we don't do local source mappings, so multiple
221 manips not an issue. */
222 if (maniptype == IP_NAT_MANIP_SRC &&
223 !(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) {
224 if (find_appropriate_src(net, zone, orig_tuple, tuple, range)) {
225 pr_debug("get_unique_tuple: Found current src map\n");
226 if (!nf_nat_used_tuple(tuple, ct))
227 return;
228 }
229 }
230
231 /* 2) Select the least-used IP/proto combination in the given
232 range. */
233 *tuple = *orig_tuple;
234 find_best_ips_proto(zone, tuple, range, ct, maniptype);
235
236 /* 3) The per-protocol part of the manip is made to map into
237 the range to make a unique tuple. */
238
239 rcu_read_lock();
240 proto = __nf_nat_proto_find(orig_tuple->dst.protonum);
241
242 /* Only bother mapping if it's not already in range and unique */
243 if (!(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) {
244 if (range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) {
245 if (proto->in_range(tuple, maniptype, &range->min,
246 &range->max) &&
247 (range->min.all == range->max.all ||
248 !nf_nat_used_tuple(tuple, ct)))
249 goto out;
250 } else if (!nf_nat_used_tuple(tuple, ct)) {
251 goto out;
252 }
253 }
254
255 /* Last change: get protocol to try to obtain unique tuple. */
256 proto->unique_tuple(tuple, range, maniptype, ct);
257out:
258 rcu_read_unlock();
259}
260
261unsigned int
262nf_nat_setup_info(struct nf_conn *ct,
263 const struct nf_nat_range *range,
264 enum nf_nat_manip_type maniptype)
265{
266 struct net *net = nf_ct_net(ct);
267 struct nf_conntrack_tuple curr_tuple, new_tuple;
268 struct nf_conn_nat *nat;
269 int have_to_hash = !(ct->status & IPS_NAT_DONE_MASK);
270
271 /* nat helper or nfctnetlink also setup binding */
272 nat = nfct_nat(ct);
273 if (!nat) {
274 nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
275 if (nat == NULL) {
276 pr_debug("failed to add NAT extension\n");
277 return NF_ACCEPT;
278 }
279 }
280
281 NF_CT_ASSERT(maniptype == IP_NAT_MANIP_SRC ||
282 maniptype == IP_NAT_MANIP_DST);
283 BUG_ON(nf_nat_initialized(ct, maniptype));
284
285 /* What we've got will look like inverse of reply. Normally
286 this is what is in the conntrack, except for prior
287 manipulations (future optimization: if num_manips == 0,
288 orig_tp =
289 conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */
290 nf_ct_invert_tuplepr(&curr_tuple,
291 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
292
293 get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
294
295 if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
296 struct nf_conntrack_tuple reply;
297
298 /* Alter conntrack table so will recognize replies. */
299 nf_ct_invert_tuplepr(&reply, &new_tuple);
300 nf_conntrack_alter_reply(ct, &reply);
301
302 /* Non-atomic: we own this at the moment. */
303 if (maniptype == IP_NAT_MANIP_SRC)
304 ct->status |= IPS_SRC_NAT;
305 else
306 ct->status |= IPS_DST_NAT;
307 }
308
309 /* Place in source hash if this is the first time. */
310 if (have_to_hash) {
311 unsigned int srchash;
312
313 srchash = hash_by_src(net, nf_ct_zone(ct),
314 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
315 spin_lock_bh(&nf_nat_lock);
316 /* nf_conntrack_alter_reply might re-allocate exntension aera */
317 nat = nfct_nat(ct);
318 nat->ct = ct;
319 hlist_add_head_rcu(&nat->bysource,
320 &net->ipv4.nat_bysource[srchash]);
321 spin_unlock_bh(&nf_nat_lock);
322 }
323
324 /* It's done. */
325 if (maniptype == IP_NAT_MANIP_DST)
326 set_bit(IPS_DST_NAT_DONE_BIT, &ct->status);
327 else
328 set_bit(IPS_SRC_NAT_DONE_BIT, &ct->status);
329
330 return NF_ACCEPT;
331}
332EXPORT_SYMBOL(nf_nat_setup_info);
333
334/* Returns true if succeeded. */
335static bool
336manip_pkt(u_int16_t proto,
337 struct sk_buff *skb,
338 unsigned int iphdroff,
339 const struct nf_conntrack_tuple *target,
340 enum nf_nat_manip_type maniptype)
341{
342 struct iphdr *iph;
343 const struct nf_nat_protocol *p;
344
345 if (!skb_make_writable(skb, iphdroff + sizeof(*iph)))
346 return false;
347
348 iph = (void *)skb->data + iphdroff;
349
350 /* Manipulate protcol part. */
351
352 /* rcu_read_lock()ed by nf_hook_slow */
353 p = __nf_nat_proto_find(proto);
354 if (!p->manip_pkt(skb, iphdroff, target, maniptype))
355 return false;
356
357 iph = (void *)skb->data + iphdroff;
358
359 if (maniptype == IP_NAT_MANIP_SRC) {
360 csum_replace4(&iph->check, iph->saddr, target->src.u3.ip);
361 iph->saddr = target->src.u3.ip;
362 } else {
363 csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip);
364 iph->daddr = target->dst.u3.ip;
365 }
366 return true;
367}
368
369/* Do packet manipulations according to nf_nat_setup_info. */
370unsigned int nf_nat_packet(struct nf_conn *ct,
371 enum ip_conntrack_info ctinfo,
372 unsigned int hooknum,
373 struct sk_buff *skb)
374{
375 enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
376 unsigned long statusbit;
377 enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
378
379 if (mtype == IP_NAT_MANIP_SRC)
380 statusbit = IPS_SRC_NAT;
381 else
382 statusbit = IPS_DST_NAT;
383
384 /* Invert if this is reply dir. */
385 if (dir == IP_CT_DIR_REPLY)
386 statusbit ^= IPS_NAT_MASK;
387
388 /* Non-atomic: these bits don't change. */
389 if (ct->status & statusbit) {
390 struct nf_conntrack_tuple target;
391
392 /* We are aiming to look like inverse of other direction. */
393 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
394
395 if (!manip_pkt(target.dst.protonum, skb, 0, &target, mtype))
396 return NF_DROP;
397 }
398 return NF_ACCEPT;
399}
400EXPORT_SYMBOL_GPL(nf_nat_packet);
401
402/* Dir is direction ICMP is coming from (opposite to packet it contains) */
403int nf_nat_icmp_reply_translation(struct nf_conn *ct,
404 enum ip_conntrack_info ctinfo,
405 unsigned int hooknum,
406 struct sk_buff *skb)
407{
408 struct {
409 struct icmphdr icmp;
410 struct iphdr ip;
411 } *inside;
412 const struct nf_conntrack_l4proto *l4proto;
413 struct nf_conntrack_tuple inner, target;
414 int hdrlen = ip_hdrlen(skb);
415 enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
416 unsigned long statusbit;
417 enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
418
419 if (!skb_make_writable(skb, hdrlen + sizeof(*inside)))
420 return 0;
421
422 inside = (void *)skb->data + hdrlen;
423
424 /* We're actually going to mangle it beyond trivial checksum
425 adjustment, so make sure the current checksum is correct. */
426 if (nf_ip_checksum(skb, hooknum, hdrlen, 0))
427 return 0;
428
429 /* Must be RELATED */
430 NF_CT_ASSERT(skb->nfctinfo == IP_CT_RELATED ||
431 skb->nfctinfo == IP_CT_RELATED+IP_CT_IS_REPLY);
432
433 /* Redirects on non-null nats must be dropped, else they'll
434 start talking to each other without our translation, and be
435 confused... --RR */
436 if (inside->icmp.type == ICMP_REDIRECT) {
437 /* If NAT isn't finished, assume it and drop. */
438 if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
439 return 0;
440
441 if (ct->status & IPS_NAT_MASK)
442 return 0;
443 }
444
445 if (manip == IP_NAT_MANIP_SRC)
446 statusbit = IPS_SRC_NAT;
447 else
448 statusbit = IPS_DST_NAT;
449
450 /* Invert if this is reply dir. */
451 if (dir == IP_CT_DIR_REPLY)
452 statusbit ^= IPS_NAT_MASK;
453
454 if (!(ct->status & statusbit))
455 return 1;
456
457 pr_debug("icmp_reply_translation: translating error %p manip %u "
458 "dir %s\n", skb, manip,
459 dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY");
460
461 /* rcu_read_lock()ed by nf_hook_slow */
462 l4proto = __nf_ct_l4proto_find(PF_INET, inside->ip.protocol);
463
464 if (!nf_ct_get_tuple(skb, hdrlen + sizeof(struct icmphdr),
465 (hdrlen +
466 sizeof(struct icmphdr) + inside->ip.ihl * 4),
467 (u_int16_t)AF_INET, inside->ip.protocol,
468 &inner, l3proto, l4proto))
469 return 0;
470
471 /* Change inner back to look like incoming packet. We do the
472 opposite manip on this hook to normal, because it might not
473 pass all hooks (locally-generated ICMP). Consider incoming
474 packet: PREROUTING (DST manip), routing produces ICMP, goes
475 through POSTROUTING (which must correct the DST manip). */
476 if (!manip_pkt(inside->ip.protocol, skb, hdrlen + sizeof(inside->icmp),
477 &ct->tuplehash[!dir].tuple, !manip))
478 return 0;
479
480 if (skb->ip_summed != CHECKSUM_PARTIAL) {
481 /* Reloading "inside" here since manip_pkt inner. */
482 inside = (void *)skb->data + hdrlen;
483 inside->icmp.checksum = 0;
484 inside->icmp.checksum =
485 csum_fold(skb_checksum(skb, hdrlen,
486 skb->len - hdrlen, 0));
487 }
488
489 /* Change outer to look the reply to an incoming packet
490 * (proto 0 means don't invert per-proto part). */
491 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
492 if (!manip_pkt(0, skb, 0, &target, manip))
493 return 0;
494
495 return 1;
496}
497EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation);
498
499/* Protocol registration. */
500int nf_nat_protocol_register(const struct nf_nat_protocol *proto)
501{
502 int ret = 0;
503
504 spin_lock_bh(&nf_nat_lock);
505 if (nf_nat_protos[proto->protonum] != &nf_nat_unknown_protocol) {
506 ret = -EBUSY;
507 goto out;
508 }
509 rcu_assign_pointer(nf_nat_protos[proto->protonum], proto);
510 out:
511 spin_unlock_bh(&nf_nat_lock);
512 return ret;
513}
514EXPORT_SYMBOL(nf_nat_protocol_register);
515
516/* Noone stores the protocol anywhere; simply delete it. */
517void nf_nat_protocol_unregister(const struct nf_nat_protocol *proto)
518{
519 spin_lock_bh(&nf_nat_lock);
520 rcu_assign_pointer(nf_nat_protos[proto->protonum],
521 &nf_nat_unknown_protocol);
522 spin_unlock_bh(&nf_nat_lock);
523 synchronize_rcu();
524}
525EXPORT_SYMBOL(nf_nat_protocol_unregister);
526
527/* Noone using conntrack by the time this called. */
528static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
529{
530 struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT);
531
532 if (nat == NULL || nat->ct == NULL)
533 return;
534
535 NF_CT_ASSERT(nat->ct->status & IPS_NAT_DONE_MASK);
536
537 spin_lock_bh(&nf_nat_lock);
538 hlist_del_rcu(&nat->bysource);
539 spin_unlock_bh(&nf_nat_lock);
540}
541
542static void nf_nat_move_storage(void *new, void *old)
543{
544 struct nf_conn_nat *new_nat = new;
545 struct nf_conn_nat *old_nat = old;
546 struct nf_conn *ct = old_nat->ct;
547
548 if (!ct || !(ct->status & IPS_NAT_DONE_MASK))
549 return;
550
551 spin_lock_bh(&nf_nat_lock);
552 new_nat->ct = ct;
553 hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource);
554 spin_unlock_bh(&nf_nat_lock);
555}
556
557static struct nf_ct_ext_type nat_extend __read_mostly = {
558 .len = sizeof(struct nf_conn_nat),
559 .align = __alignof__(struct nf_conn_nat),
560 .destroy = nf_nat_cleanup_conntrack,
561 .move = nf_nat_move_storage,
562 .id = NF_CT_EXT_NAT,
563 .flags = NF_CT_EXT_F_PREALLOC,
564};
565
566#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
567
568#include <linux/netfilter/nfnetlink.h>
569#include <linux/netfilter/nfnetlink_conntrack.h>
570
571static const struct nf_nat_protocol *
572nf_nat_proto_find_get(u_int8_t protonum)
573{
574 const struct nf_nat_protocol *p;
575
576 rcu_read_lock();
577 p = __nf_nat_proto_find(protonum);
578 if (!try_module_get(p->me))
579 p = &nf_nat_unknown_protocol;
580 rcu_read_unlock();
581
582 return p;
583}
584
585static void
586nf_nat_proto_put(const struct nf_nat_protocol *p)
587{
588 module_put(p->me);
589}
590
591static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = {
592 [CTA_PROTONAT_PORT_MIN] = { .type = NLA_U16 },
593 [CTA_PROTONAT_PORT_MAX] = { .type = NLA_U16 },
594};
595
596static int nfnetlink_parse_nat_proto(struct nlattr *attr,
597 const struct nf_conn *ct,
598 struct nf_nat_range *range)
599{
600 struct nlattr *tb[CTA_PROTONAT_MAX+1];
601 const struct nf_nat_protocol *npt;
602 int err;
603
604 err = nla_parse_nested(tb, CTA_PROTONAT_MAX, attr, protonat_nla_policy);
605 if (err < 0)
606 return err;
607
608 npt = nf_nat_proto_find_get(nf_ct_protonum(ct));
609 if (npt->nlattr_to_range)
610 err = npt->nlattr_to_range(tb, range);
611 nf_nat_proto_put(npt);
612 return err;
613}
614
615static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
616 [CTA_NAT_MINIP] = { .type = NLA_U32 },
617 [CTA_NAT_MAXIP] = { .type = NLA_U32 },
618};
619
620static int
621nfnetlink_parse_nat(const struct nlattr *nat,
622 const struct nf_conn *ct, struct nf_nat_range *range)
623{
624 struct nlattr *tb[CTA_NAT_MAX+1];
625 int err;
626
627 memset(range, 0, sizeof(*range));
628
629 err = nla_parse_nested(tb, CTA_NAT_MAX, nat, nat_nla_policy);
630 if (err < 0)
631 return err;
632
633 if (tb[CTA_NAT_MINIP])
634 range->min_ip = nla_get_be32(tb[CTA_NAT_MINIP]);
635
636 if (!tb[CTA_NAT_MAXIP])
637 range->max_ip = range->min_ip;
638 else
639 range->max_ip = nla_get_be32(tb[CTA_NAT_MAXIP]);
640
641 if (range->min_ip)
642 range->flags |= IP_NAT_RANGE_MAP_IPS;
643
644 if (!tb[CTA_NAT_PROTO])
645 return 0;
646
647 err = nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range);
648 if (err < 0)
649 return err;
650
651 return 0;
652}
653
654static int
655nfnetlink_parse_nat_setup(struct nf_conn *ct,
656 enum nf_nat_manip_type manip,
657 const struct nlattr *attr)
658{
659 struct nf_nat_range range;
660
661 if (nfnetlink_parse_nat(attr, ct, &range) < 0)
662 return -EINVAL;
663 if (nf_nat_initialized(ct, manip))
664 return -EEXIST;
665
666 return nf_nat_setup_info(ct, &range, manip);
667}
668#else
669static int
670nfnetlink_parse_nat_setup(struct nf_conn *ct,
671 enum nf_nat_manip_type manip,
672 const struct nlattr *attr)
673{
674 return -EOPNOTSUPP;
675}
676#endif
677
678static int __net_init nf_nat_net_init(struct net *net)
679{
680 /* Leave them the same for the moment. */
681 net->ipv4.nat_htable_size = net->ct.htable_size;
682 net->ipv4.nat_bysource = nf_ct_alloc_hashtable(&net->ipv4.nat_htable_size,
683 &net->ipv4.nat_vmalloced, 0);
684 if (!net->ipv4.nat_bysource)
685 return -ENOMEM;
686 return 0;
687}
688
689/* Clear NAT section of all conntracks, in case we're loaded again. */
690static int clean_nat(struct nf_conn *i, void *data)
691{
692 struct nf_conn_nat *nat = nfct_nat(i);
693
694 if (!nat)
695 return 0;
696 memset(nat, 0, sizeof(*nat));
697 i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST);
698 return 0;
699}
700
701static void __net_exit nf_nat_net_exit(struct net *net)
702{
703 nf_ct_iterate_cleanup(net, &clean_nat, NULL);
704 synchronize_rcu();
705 nf_ct_free_hashtable(net->ipv4.nat_bysource, net->ipv4.nat_vmalloced,
706 net->ipv4.nat_htable_size);
707}
708
709static struct pernet_operations nf_nat_net_ops = {
710 .init = nf_nat_net_init,
711 .exit = nf_nat_net_exit,
712};
713
714static int __init nf_nat_init(void)
715{
716 size_t i;
717 int ret;
718
719 need_ipv4_conntrack();
720
721 ret = nf_ct_extend_register(&nat_extend);
722 if (ret < 0) {
723 printk(KERN_ERR "nf_nat_core: Unable to register extension\n");
724 return ret;
725 }
726
727 ret = register_pernet_subsys(&nf_nat_net_ops);
728 if (ret < 0)
729 goto cleanup_extend;
730
731 /* Sew in builtin protocols. */
732 spin_lock_bh(&nf_nat_lock);
733 for (i = 0; i < MAX_IP_NAT_PROTO; i++)
734 rcu_assign_pointer(nf_nat_protos[i], &nf_nat_unknown_protocol);
735 rcu_assign_pointer(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp);
736 rcu_assign_pointer(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp);
737 rcu_assign_pointer(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp);
738 spin_unlock_bh(&nf_nat_lock);
739
740 /* Initialize fake conntrack so that NAT will skip it */
741 nf_ct_untracked_status_or(IPS_NAT_DONE_MASK);
742
743 l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET);
744
745 BUG_ON(nf_nat_seq_adjust_hook != NULL);
746 rcu_assign_pointer(nf_nat_seq_adjust_hook, nf_nat_seq_adjust);
747 BUG_ON(nfnetlink_parse_nat_setup_hook != NULL);
748 rcu_assign_pointer(nfnetlink_parse_nat_setup_hook,
749 nfnetlink_parse_nat_setup);
750 BUG_ON(nf_ct_nat_offset != NULL);
751 rcu_assign_pointer(nf_ct_nat_offset, nf_nat_get_offset);
752 return 0;
753
754 cleanup_extend:
755 nf_ct_extend_unregister(&nat_extend);
756 return ret;
757}
758
759static void __exit nf_nat_cleanup(void)
760{
761 unregister_pernet_subsys(&nf_nat_net_ops);
762 nf_ct_l3proto_put(l3proto);
763 nf_ct_extend_unregister(&nat_extend);
764 rcu_assign_pointer(nf_nat_seq_adjust_hook, NULL);
765 rcu_assign_pointer(nfnetlink_parse_nat_setup_hook, NULL);
766 rcu_assign_pointer(nf_ct_nat_offset, NULL);
767 synchronize_net();
768}
769
770MODULE_LICENSE("GPL");
771MODULE_ALIAS("nf-nat-ipv4");
772
773module_init(nf_nat_init);
774module_exit(nf_nat_cleanup);
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