Commit | Line | Data |
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5b1158e9 JK |
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 | { | |
e22a0548 | 56 | return rcu_dereference(nf_nat_protos[protonum]); |
5b1158e9 JK |
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 | ||
e22a0548 | 64 | rcu_read_lock(); |
5b1158e9 JK |
65 | p = __nf_nat_proto_find(protonum); |
66 | if (!try_module_get(p->me)) | |
67 | p = &nf_nat_unknown_protocol; | |
e22a0548 | 68 | rcu_read_unlock(); |
5b1158e9 JK |
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); | |
e54cbc1f | 100 | nat->info.ct = NULL; |
5b1158e9 JK |
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; | |
e22a0548 | 128 | int ret = 0; |
5b1158e9 | 129 | |
5b1158e9 JK |
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 | ||
e22a0548 PM |
138 | rcu_read_lock(); |
139 | proto = __nf_nat_proto_find(tuple->dst.protonum); | |
5b1158e9 JK |
140 | if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) || |
141 | proto->in_range(tuple, IP_NAT_MANIP_SRC, | |
142 | &range->min, &range->max)) | |
e22a0548 PM |
143 | ret = 1; |
144 | rcu_read_unlock(); | |
5b1158e9 | 145 | |
e22a0548 | 146 | return ret; |
5b1158e9 JK |
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) { | |
e54cbc1f | 173 | ct = nat->info.ct; |
5b1158e9 JK |
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"); | |
41f4689a EL |
259 | if (!(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) |
260 | if (!nf_nat_used_tuple(tuple, ct)) | |
261 | return; | |
5b1158e9 JK |
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 | ||
e22a0548 PM |
273 | rcu_read_lock(); |
274 | proto = __nf_nat_proto_find(orig_tuple->dst.protonum); | |
5b1158e9 | 275 | |
41f4689a EL |
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); | |
e22a0548 | 279 | goto out; |
41f4689a EL |
280 | } |
281 | ||
5b1158e9 JK |
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)) && | |
e22a0548 PM |
285 | !nf_nat_used_tuple(tuple, ct)) |
286 | goto out; | |
5b1158e9 JK |
287 | |
288 | /* Last change: get protocol to try to obtain unique tuple. */ | |
289 | proto->unique_tuple(tuple, range, maniptype, ct); | |
e22a0548 PM |
290 | out: |
291 | rcu_read_unlock(); | |
5b1158e9 JK |
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; | |
2d59e5ca YK |
300 | struct nf_conn_nat *nat; |
301 | struct nf_nat_info *info; | |
5b1158e9 JK |
302 | int have_to_hash = !(ct->status & IPS_NAT_DONE_MASK); |
303 | enum nf_nat_manip_type maniptype = HOOK2MANIP(hooknum); | |
304 | ||
2d59e5ca YK |
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 | ||
5b1158e9 JK |
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); | |
2d59e5ca YK |
351 | /* nf_conntrack_alter_reply might re-allocate exntension aera */ |
352 | info = &nfct_nat(ct)->info; | |
e54cbc1f | 353 | info->ct = ct; |
5b1158e9 JK |
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. */ | |
e22a0548 PM |
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)) | |
5b1158e9 | 389 | return 0; |
5b1158e9 JK |
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; | |
923f4902 | 446 | struct nf_conntrack_l4proto *l4proto; |
5b1158e9 | 447 | struct nf_conntrack_tuple inner, target; |
c9bdd4b5 | 448 | int hdrlen = ip_hdrlen(*pskb); |
5b1158e9 JK |
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 | ||
c9bdd4b5 | 456 | inside = (void *)(*pskb)->data + ip_hdrlen(*pskb); |
5b1158e9 JK |
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 | |
e905a9ed YH |
468 | start talking to each other without our translation, and be |
469 | confused... --RR */ | |
5b1158e9 JK |
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 | ||
923f4902 PM |
482 | /* rcu_read_lock()ed by nf_hook_slow */ |
483 | l4proto = __nf_ct_l4proto_find(PF_INET, inside->ip.protocol); | |
484 | ||
5b1158e9 | 485 | if (!nf_ct_get_tuple(*pskb, |
c9bdd4b5 ACM |
486 | ip_hdrlen(*pskb) + sizeof(struct icmphdr), |
487 | (ip_hdrlen(*pskb) + | |
488 | sizeof(struct icmphdr) + inside->ip.ihl * 4), | |
e905a9ed YH |
489 | (u_int16_t)AF_INET, |
490 | inside->ip.protocol, | |
923f4902 | 491 | &inner, l3proto, l4proto)) |
5b1158e9 JK |
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, | |
c9bdd4b5 | 500 | ip_hdrlen(*pskb) + sizeof(inside->icmp), |
5b1158e9 JK |
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. */ | |
c9bdd4b5 | 507 | inside = (void *)(*pskb)->data + ip_hdrlen(*pskb); |
5b1158e9 JK |
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 | } | |
e22a0548 | 545 | rcu_assign_pointer(nf_nat_protos[proto->protonum], proto); |
5b1158e9 JK |
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); | |
e22a0548 PM |
556 | rcu_assign_pointer(nf_nat_protos[proto->protonum], |
557 | &nf_nat_unknown_protocol); | |
5b1158e9 | 558 | write_unlock_bh(&nf_nat_lock); |
e22a0548 | 559 | synchronize_rcu(); |
5b1158e9 JK |
560 | } |
561 | EXPORT_SYMBOL(nf_nat_protocol_unregister); | |
562 | ||
e281db5c | 563 | #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
5b1158e9 JK |
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 | ||
2d59e5ca YK |
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 | ||
5b1158e9 JK |
633 | static int __init nf_nat_init(void) |
634 | { | |
635 | size_t i; | |
2d59e5ca YK |
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 | } | |
5b1158e9 JK |
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); | |
2d59e5ca YK |
649 | if (!bysource) { |
650 | ret = -ENOMEM; | |
651 | goto cleanup_extend; | |
652 | } | |
5b1158e9 JK |
653 | |
654 | /* Sew in builtin protocols. */ | |
655 | write_lock_bh(&nf_nat_lock); | |
656 | for (i = 0; i < MAX_IP_NAT_PROTO; i++) | |
e22a0548 PM |
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); | |
5b1158e9 JK |
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> */ | |
982d9a9c PM |
668 | NF_CT_ASSERT(rcu_dereference(nf_conntrack_destroyed) == NULL); |
669 | rcu_assign_pointer(nf_conntrack_destroyed, nf_nat_cleanup_conntrack); | |
5b1158e9 JK |
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; | |
2d59e5ca YK |
676 | |
677 | cleanup_extend: | |
678 | nf_ct_extend_unregister(&nat_extend); | |
679 | return ret; | |
5b1158e9 JK |
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); | |
982d9a9c PM |
697 | rcu_assign_pointer(nf_conntrack_destroyed, NULL); |
698 | synchronize_rcu(); | |
5b1158e9 JK |
699 | vfree(bysource); |
700 | nf_ct_l3proto_put(l3proto); | |
2d59e5ca | 701 | nf_ct_extend_unregister(&nat_extend); |
5b1158e9 JK |
702 | } |
703 | ||
704 | MODULE_LICENSE("GPL"); | |
705 | ||
706 | module_init(nf_nat_init); | |
707 | module_exit(nf_nat_cleanup); |