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> | |
5b1158e9 JK |
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 | ||
5b1158e9 JK |
34 | static DEFINE_RWLOCK(nf_nat_lock); |
35 | ||
ce4b1ceb | 36 | static struct nf_conntrack_l3proto *l3proto __read_mostly; |
5b1158e9 JK |
37 | |
38 | /* Calculated at init based on memory size */ | |
ce4b1ceb | 39 | static unsigned int nf_nat_htable_size __read_mostly; |
53aba597 | 40 | static int nf_nat_vmalloced; |
5b1158e9 | 41 | |
ce4b1ceb | 42 | static struct hlist_head *bysource __read_mostly; |
5b1158e9 JK |
43 | |
44 | #define MAX_IP_NAT_PROTO 256 | |
ce4b1ceb PM |
45 | static const struct nf_nat_protocol *nf_nat_protos[MAX_IP_NAT_PROTO] |
46 | __read_mostly; | |
5b1158e9 | 47 | |
2b628a08 | 48 | static inline const struct nf_nat_protocol * |
5b1158e9 JK |
49 | __nf_nat_proto_find(u_int8_t protonum) |
50 | { | |
e22a0548 | 51 | return rcu_dereference(nf_nat_protos[protonum]); |
5b1158e9 JK |
52 | } |
53 | ||
2b628a08 | 54 | const struct nf_nat_protocol * |
5b1158e9 JK |
55 | nf_nat_proto_find_get(u_int8_t protonum) |
56 | { | |
2b628a08 | 57 | const struct nf_nat_protocol *p; |
5b1158e9 | 58 | |
e22a0548 | 59 | rcu_read_lock(); |
5b1158e9 JK |
60 | p = __nf_nat_proto_find(protonum); |
61 | if (!try_module_get(p->me)) | |
62 | p = &nf_nat_unknown_protocol; | |
e22a0548 | 63 | rcu_read_unlock(); |
5b1158e9 JK |
64 | |
65 | return p; | |
66 | } | |
67 | EXPORT_SYMBOL_GPL(nf_nat_proto_find_get); | |
68 | ||
69 | void | |
2b628a08 | 70 | nf_nat_proto_put(const struct nf_nat_protocol *p) |
5b1158e9 JK |
71 | { |
72 | module_put(p->me); | |
73 | } | |
74 | EXPORT_SYMBOL_GPL(nf_nat_proto_put); | |
75 | ||
76 | /* We keep an extra hash for each conntrack, for fast searching. */ | |
77 | static inline unsigned int | |
78 | hash_by_src(const struct nf_conntrack_tuple *tuple) | |
79 | { | |
80 | /* Original src, to ensure we map it consistently if poss. */ | |
a34c4589 AV |
81 | return jhash_3words((__force u32)tuple->src.u3.ip, |
82 | (__force u32)tuple->src.u.all, | |
5b1158e9 JK |
83 | tuple->dst.protonum, 0) % nf_nat_htable_size; |
84 | } | |
85 | ||
5b1158e9 JK |
86 | /* Is this tuple already taken? (not by us) */ |
87 | int | |
88 | nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple, | |
89 | const struct nf_conn *ignored_conntrack) | |
90 | { | |
91 | /* Conntrack tracking doesn't keep track of outgoing tuples; only | |
92 | incoming ones. NAT means they don't have a fixed mapping, | |
93 | so we invert the tuple and look for the incoming reply. | |
94 | ||
95 | We could keep a separate hash if this proves too slow. */ | |
96 | struct nf_conntrack_tuple reply; | |
97 | ||
98 | nf_ct_invert_tuplepr(&reply, tuple); | |
99 | return nf_conntrack_tuple_taken(&reply, ignored_conntrack); | |
100 | } | |
101 | EXPORT_SYMBOL(nf_nat_used_tuple); | |
102 | ||
103 | /* If we source map this tuple so reply looks like reply_tuple, will | |
104 | * that meet the constraints of range. */ | |
105 | static int | |
106 | in_range(const struct nf_conntrack_tuple *tuple, | |
107 | const struct nf_nat_range *range) | |
108 | { | |
2b628a08 | 109 | const struct nf_nat_protocol *proto; |
e22a0548 | 110 | int ret = 0; |
5b1158e9 | 111 | |
5b1158e9 JK |
112 | /* If we are supposed to map IPs, then we must be in the |
113 | range specified, otherwise let this drag us onto a new src IP. */ | |
114 | if (range->flags & IP_NAT_RANGE_MAP_IPS) { | |
115 | if (ntohl(tuple->src.u3.ip) < ntohl(range->min_ip) || | |
116 | ntohl(tuple->src.u3.ip) > ntohl(range->max_ip)) | |
117 | return 0; | |
118 | } | |
119 | ||
e22a0548 PM |
120 | rcu_read_lock(); |
121 | proto = __nf_nat_proto_find(tuple->dst.protonum); | |
5b1158e9 JK |
122 | if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) || |
123 | proto->in_range(tuple, IP_NAT_MANIP_SRC, | |
124 | &range->min, &range->max)) | |
e22a0548 PM |
125 | ret = 1; |
126 | rcu_read_unlock(); | |
5b1158e9 | 127 | |
e22a0548 | 128 | return ret; |
5b1158e9 JK |
129 | } |
130 | ||
131 | static inline int | |
132 | same_src(const struct nf_conn *ct, | |
133 | const struct nf_conntrack_tuple *tuple) | |
134 | { | |
135 | const struct nf_conntrack_tuple *t; | |
136 | ||
137 | t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; | |
138 | return (t->dst.protonum == tuple->dst.protonum && | |
139 | t->src.u3.ip == tuple->src.u3.ip && | |
140 | t->src.u.all == tuple->src.u.all); | |
141 | } | |
142 | ||
143 | /* Only called for SRC manip */ | |
144 | static int | |
145 | find_appropriate_src(const struct nf_conntrack_tuple *tuple, | |
146 | struct nf_conntrack_tuple *result, | |
147 | const struct nf_nat_range *range) | |
148 | { | |
149 | unsigned int h = hash_by_src(tuple); | |
150 | struct nf_conn_nat *nat; | |
151 | struct nf_conn *ct; | |
53aba597 | 152 | struct hlist_node *n; |
5b1158e9 JK |
153 | |
154 | read_lock_bh(&nf_nat_lock); | |
53aba597 | 155 | hlist_for_each_entry(nat, n, &bysource[h], bysource) { |
b6b84d4a | 156 | ct = nat->ct; |
5b1158e9 JK |
157 | if (same_src(ct, tuple)) { |
158 | /* Copy source part from reply tuple. */ | |
159 | nf_ct_invert_tuplepr(result, | |
160 | &ct->tuplehash[IP_CT_DIR_REPLY].tuple); | |
161 | result->dst = tuple->dst; | |
162 | ||
163 | if (in_range(result, range)) { | |
164 | read_unlock_bh(&nf_nat_lock); | |
165 | return 1; | |
166 | } | |
167 | } | |
168 | } | |
169 | read_unlock_bh(&nf_nat_lock); | |
170 | return 0; | |
171 | } | |
172 | ||
173 | /* For [FUTURE] fragmentation handling, we want the least-used | |
174 | src-ip/dst-ip/proto triple. Fairness doesn't come into it. Thus | |
175 | if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports | |
176 | 1-65535, we don't do pro-rata allocation based on ports; we choose | |
177 | the ip with the lowest src-ip/dst-ip/proto usage. | |
178 | */ | |
179 | static void | |
180 | find_best_ips_proto(struct nf_conntrack_tuple *tuple, | |
181 | const struct nf_nat_range *range, | |
182 | const struct nf_conn *ct, | |
183 | enum nf_nat_manip_type maniptype) | |
184 | { | |
185 | __be32 *var_ipp; | |
186 | /* Host order */ | |
187 | u_int32_t minip, maxip, j; | |
188 | ||
189 | /* No IP mapping? Do nothing. */ | |
190 | if (!(range->flags & IP_NAT_RANGE_MAP_IPS)) | |
191 | return; | |
192 | ||
193 | if (maniptype == IP_NAT_MANIP_SRC) | |
194 | var_ipp = &tuple->src.u3.ip; | |
195 | else | |
196 | var_ipp = &tuple->dst.u3.ip; | |
197 | ||
198 | /* Fast path: only one choice. */ | |
199 | if (range->min_ip == range->max_ip) { | |
200 | *var_ipp = range->min_ip; | |
201 | return; | |
202 | } | |
203 | ||
204 | /* Hashing source and destination IPs gives a fairly even | |
205 | * spread in practice (if there are a small number of IPs | |
206 | * involved, there usually aren't that many connections | |
207 | * anyway). The consistency means that servers see the same | |
208 | * client coming from the same IP (some Internet Banking sites | |
209 | * like this), even across reboots. */ | |
210 | minip = ntohl(range->min_ip); | |
211 | maxip = ntohl(range->max_ip); | |
212 | j = jhash_2words((__force u32)tuple->src.u3.ip, | |
213 | (__force u32)tuple->dst.u3.ip, 0); | |
214 | *var_ipp = htonl(minip + j % (maxip - minip + 1)); | |
215 | } | |
216 | ||
6e23ae2a PM |
217 | /* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING, |
218 | * we change the source to map into the range. For NF_INET_PRE_ROUTING | |
219 | * and NF_INET_LOCAL_OUT, we change the destination to map into the | |
5b1158e9 JK |
220 | * range. It might not be possible to get a unique tuple, but we try. |
221 | * At worst (or if we race), we will end up with a final duplicate in | |
222 | * __ip_conntrack_confirm and drop the packet. */ | |
223 | static void | |
224 | get_unique_tuple(struct nf_conntrack_tuple *tuple, | |
225 | const struct nf_conntrack_tuple *orig_tuple, | |
226 | const struct nf_nat_range *range, | |
227 | struct nf_conn *ct, | |
228 | enum nf_nat_manip_type maniptype) | |
229 | { | |
2b628a08 | 230 | const struct nf_nat_protocol *proto; |
5b1158e9 JK |
231 | |
232 | /* 1) If this srcip/proto/src-proto-part is currently mapped, | |
233 | and that same mapping gives a unique tuple within the given | |
234 | range, use that. | |
235 | ||
236 | This is only required for source (ie. NAT/masq) mappings. | |
237 | So far, we don't do local source mappings, so multiple | |
238 | manips not an issue. */ | |
239 | if (maniptype == IP_NAT_MANIP_SRC) { | |
240 | if (find_appropriate_src(orig_tuple, tuple, range)) { | |
0d53778e | 241 | pr_debug("get_unique_tuple: Found current src map\n"); |
41f4689a EL |
242 | if (!(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) |
243 | if (!nf_nat_used_tuple(tuple, ct)) | |
244 | return; | |
5b1158e9 JK |
245 | } |
246 | } | |
247 | ||
248 | /* 2) Select the least-used IP/proto combination in the given | |
249 | range. */ | |
250 | *tuple = *orig_tuple; | |
251 | find_best_ips_proto(tuple, range, ct, maniptype); | |
252 | ||
253 | /* 3) The per-protocol part of the manip is made to map into | |
254 | the range to make a unique tuple. */ | |
255 | ||
e22a0548 PM |
256 | rcu_read_lock(); |
257 | proto = __nf_nat_proto_find(orig_tuple->dst.protonum); | |
5b1158e9 | 258 | |
41f4689a EL |
259 | /* Change protocol info to have some randomization */ |
260 | if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) { | |
261 | proto->unique_tuple(tuple, range, maniptype, ct); | |
e22a0548 | 262 | goto out; |
41f4689a EL |
263 | } |
264 | ||
5b1158e9 JK |
265 | /* Only bother mapping if it's not already in range and unique */ |
266 | if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) || | |
267 | proto->in_range(tuple, maniptype, &range->min, &range->max)) && | |
e22a0548 PM |
268 | !nf_nat_used_tuple(tuple, ct)) |
269 | goto out; | |
5b1158e9 JK |
270 | |
271 | /* Last change: get protocol to try to obtain unique tuple. */ | |
272 | proto->unique_tuple(tuple, range, maniptype, ct); | |
e22a0548 PM |
273 | out: |
274 | rcu_read_unlock(); | |
5b1158e9 JK |
275 | } |
276 | ||
277 | unsigned int | |
278 | nf_nat_setup_info(struct nf_conn *ct, | |
279 | const struct nf_nat_range *range, | |
280 | unsigned int hooknum) | |
281 | { | |
282 | struct nf_conntrack_tuple curr_tuple, new_tuple; | |
2d59e5ca | 283 | struct nf_conn_nat *nat; |
5b1158e9 JK |
284 | int have_to_hash = !(ct->status & IPS_NAT_DONE_MASK); |
285 | enum nf_nat_manip_type maniptype = HOOK2MANIP(hooknum); | |
286 | ||
2d59e5ca YK |
287 | /* nat helper or nfctnetlink also setup binding */ |
288 | nat = nfct_nat(ct); | |
289 | if (!nat) { | |
290 | nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC); | |
291 | if (nat == NULL) { | |
0d53778e | 292 | pr_debug("failed to add NAT extension\n"); |
2d59e5ca YK |
293 | return NF_ACCEPT; |
294 | } | |
295 | } | |
296 | ||
6e23ae2a PM |
297 | NF_CT_ASSERT(hooknum == NF_INET_PRE_ROUTING || |
298 | hooknum == NF_INET_POST_ROUTING || | |
299 | hooknum == NF_INET_LOCAL_IN || | |
300 | hooknum == NF_INET_LOCAL_OUT); | |
5b1158e9 JK |
301 | BUG_ON(nf_nat_initialized(ct, maniptype)); |
302 | ||
303 | /* What we've got will look like inverse of reply. Normally | |
304 | this is what is in the conntrack, except for prior | |
305 | manipulations (future optimization: if num_manips == 0, | |
306 | orig_tp = | |
307 | conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */ | |
308 | nf_ct_invert_tuplepr(&curr_tuple, | |
309 | &ct->tuplehash[IP_CT_DIR_REPLY].tuple); | |
310 | ||
311 | get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype); | |
312 | ||
313 | if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) { | |
314 | struct nf_conntrack_tuple reply; | |
315 | ||
316 | /* Alter conntrack table so will recognize replies. */ | |
317 | nf_ct_invert_tuplepr(&reply, &new_tuple); | |
318 | nf_conntrack_alter_reply(ct, &reply); | |
319 | ||
320 | /* Non-atomic: we own this at the moment. */ | |
321 | if (maniptype == IP_NAT_MANIP_SRC) | |
322 | ct->status |= IPS_SRC_NAT; | |
323 | else | |
324 | ct->status |= IPS_DST_NAT; | |
325 | } | |
326 | ||
327 | /* Place in source hash if this is the first time. */ | |
328 | if (have_to_hash) { | |
329 | unsigned int srchash; | |
330 | ||
331 | srchash = hash_by_src(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); | |
332 | write_lock_bh(&nf_nat_lock); | |
2d59e5ca | 333 | /* nf_conntrack_alter_reply might re-allocate exntension aera */ |
b6b84d4a YK |
334 | nat = nfct_nat(ct); |
335 | nat->ct = ct; | |
53aba597 | 336 | hlist_add_head(&nat->bysource, &bysource[srchash]); |
5b1158e9 JK |
337 | write_unlock_bh(&nf_nat_lock); |
338 | } | |
339 | ||
340 | /* It's done. */ | |
341 | if (maniptype == IP_NAT_MANIP_DST) | |
342 | set_bit(IPS_DST_NAT_DONE_BIT, &ct->status); | |
343 | else | |
344 | set_bit(IPS_SRC_NAT_DONE_BIT, &ct->status); | |
345 | ||
346 | return NF_ACCEPT; | |
347 | } | |
348 | EXPORT_SYMBOL(nf_nat_setup_info); | |
349 | ||
350 | /* Returns true if succeeded. */ | |
351 | static int | |
352 | manip_pkt(u_int16_t proto, | |
3db05fea | 353 | struct sk_buff *skb, |
5b1158e9 JK |
354 | unsigned int iphdroff, |
355 | const struct nf_conntrack_tuple *target, | |
356 | enum nf_nat_manip_type maniptype) | |
357 | { | |
358 | struct iphdr *iph; | |
2b628a08 | 359 | const struct nf_nat_protocol *p; |
5b1158e9 | 360 | |
3db05fea | 361 | if (!skb_make_writable(skb, iphdroff + sizeof(*iph))) |
5b1158e9 JK |
362 | return 0; |
363 | ||
3db05fea | 364 | iph = (void *)skb->data + iphdroff; |
5b1158e9 JK |
365 | |
366 | /* Manipulate protcol part. */ | |
e22a0548 PM |
367 | |
368 | /* rcu_read_lock()ed by nf_hook_slow */ | |
369 | p = __nf_nat_proto_find(proto); | |
3db05fea | 370 | if (!p->manip_pkt(skb, iphdroff, target, maniptype)) |
5b1158e9 | 371 | return 0; |
5b1158e9 | 372 | |
3db05fea | 373 | iph = (void *)skb->data + iphdroff; |
5b1158e9 JK |
374 | |
375 | if (maniptype == IP_NAT_MANIP_SRC) { | |
be0ea7d5 | 376 | csum_replace4(&iph->check, iph->saddr, target->src.u3.ip); |
5b1158e9 JK |
377 | iph->saddr = target->src.u3.ip; |
378 | } else { | |
be0ea7d5 | 379 | csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip); |
5b1158e9 JK |
380 | iph->daddr = target->dst.u3.ip; |
381 | } | |
382 | return 1; | |
383 | } | |
384 | ||
385 | /* Do packet manipulations according to nf_nat_setup_info. */ | |
386 | unsigned int nf_nat_packet(struct nf_conn *ct, | |
387 | enum ip_conntrack_info ctinfo, | |
388 | unsigned int hooknum, | |
3db05fea | 389 | struct sk_buff *skb) |
5b1158e9 JK |
390 | { |
391 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); | |
392 | unsigned long statusbit; | |
393 | enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum); | |
394 | ||
395 | if (mtype == IP_NAT_MANIP_SRC) | |
396 | statusbit = IPS_SRC_NAT; | |
397 | else | |
398 | statusbit = IPS_DST_NAT; | |
399 | ||
400 | /* Invert if this is reply dir. */ | |
401 | if (dir == IP_CT_DIR_REPLY) | |
402 | statusbit ^= IPS_NAT_MASK; | |
403 | ||
404 | /* Non-atomic: these bits don't change. */ | |
405 | if (ct->status & statusbit) { | |
406 | struct nf_conntrack_tuple target; | |
407 | ||
408 | /* We are aiming to look like inverse of other direction. */ | |
409 | nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple); | |
410 | ||
3db05fea | 411 | if (!manip_pkt(target.dst.protonum, skb, 0, &target, mtype)) |
5b1158e9 JK |
412 | return NF_DROP; |
413 | } | |
414 | return NF_ACCEPT; | |
415 | } | |
416 | EXPORT_SYMBOL_GPL(nf_nat_packet); | |
417 | ||
418 | /* Dir is direction ICMP is coming from (opposite to packet it contains) */ | |
419 | int nf_nat_icmp_reply_translation(struct nf_conn *ct, | |
420 | enum ip_conntrack_info ctinfo, | |
421 | unsigned int hooknum, | |
3db05fea | 422 | struct sk_buff *skb) |
5b1158e9 JK |
423 | { |
424 | struct { | |
425 | struct icmphdr icmp; | |
426 | struct iphdr ip; | |
427 | } *inside; | |
923f4902 | 428 | struct nf_conntrack_l4proto *l4proto; |
5b1158e9 | 429 | struct nf_conntrack_tuple inner, target; |
3db05fea | 430 | int hdrlen = ip_hdrlen(skb); |
5b1158e9 JK |
431 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
432 | unsigned long statusbit; | |
433 | enum nf_nat_manip_type manip = HOOK2MANIP(hooknum); | |
434 | ||
3db05fea | 435 | if (!skb_make_writable(skb, hdrlen + sizeof(*inside))) |
5b1158e9 JK |
436 | return 0; |
437 | ||
3db05fea | 438 | inside = (void *)skb->data + ip_hdrlen(skb); |
5b1158e9 JK |
439 | |
440 | /* We're actually going to mangle it beyond trivial checksum | |
441 | adjustment, so make sure the current checksum is correct. */ | |
3db05fea | 442 | if (nf_ip_checksum(skb, hooknum, hdrlen, 0)) |
5b1158e9 JK |
443 | return 0; |
444 | ||
445 | /* Must be RELATED */ | |
3db05fea HX |
446 | NF_CT_ASSERT(skb->nfctinfo == IP_CT_RELATED || |
447 | skb->nfctinfo == IP_CT_RELATED+IP_CT_IS_REPLY); | |
5b1158e9 JK |
448 | |
449 | /* Redirects on non-null nats must be dropped, else they'll | |
e905a9ed YH |
450 | start talking to each other without our translation, and be |
451 | confused... --RR */ | |
5b1158e9 JK |
452 | if (inside->icmp.type == ICMP_REDIRECT) { |
453 | /* If NAT isn't finished, assume it and drop. */ | |
454 | if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK) | |
455 | return 0; | |
456 | ||
457 | if (ct->status & IPS_NAT_MASK) | |
458 | return 0; | |
459 | } | |
460 | ||
0d53778e | 461 | pr_debug("icmp_reply_translation: translating error %p manip %u " |
3db05fea | 462 | "dir %s\n", skb, manip, |
0d53778e | 463 | dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY"); |
5b1158e9 | 464 | |
923f4902 PM |
465 | /* rcu_read_lock()ed by nf_hook_slow */ |
466 | l4proto = __nf_ct_l4proto_find(PF_INET, inside->ip.protocol); | |
467 | ||
3db05fea HX |
468 | if (!nf_ct_get_tuple(skb, |
469 | ip_hdrlen(skb) + sizeof(struct icmphdr), | |
470 | (ip_hdrlen(skb) + | |
c9bdd4b5 | 471 | sizeof(struct icmphdr) + inside->ip.ihl * 4), |
e905a9ed YH |
472 | (u_int16_t)AF_INET, |
473 | inside->ip.protocol, | |
923f4902 | 474 | &inner, l3proto, l4proto)) |
5b1158e9 JK |
475 | return 0; |
476 | ||
477 | /* Change inner back to look like incoming packet. We do the | |
478 | opposite manip on this hook to normal, because it might not | |
479 | pass all hooks (locally-generated ICMP). Consider incoming | |
480 | packet: PREROUTING (DST manip), routing produces ICMP, goes | |
481 | through POSTROUTING (which must correct the DST manip). */ | |
3db05fea HX |
482 | if (!manip_pkt(inside->ip.protocol, skb, |
483 | ip_hdrlen(skb) + sizeof(inside->icmp), | |
5b1158e9 JK |
484 | &ct->tuplehash[!dir].tuple, |
485 | !manip)) | |
486 | return 0; | |
487 | ||
3db05fea | 488 | if (skb->ip_summed != CHECKSUM_PARTIAL) { |
5b1158e9 | 489 | /* Reloading "inside" here since manip_pkt inner. */ |
3db05fea | 490 | inside = (void *)skb->data + ip_hdrlen(skb); |
5b1158e9 JK |
491 | inside->icmp.checksum = 0; |
492 | inside->icmp.checksum = | |
3db05fea HX |
493 | csum_fold(skb_checksum(skb, hdrlen, |
494 | skb->len - hdrlen, 0)); | |
5b1158e9 JK |
495 | } |
496 | ||
497 | /* Change outer to look the reply to an incoming packet | |
498 | * (proto 0 means don't invert per-proto part). */ | |
499 | if (manip == IP_NAT_MANIP_SRC) | |
500 | statusbit = IPS_SRC_NAT; | |
501 | else | |
502 | statusbit = IPS_DST_NAT; | |
503 | ||
504 | /* Invert if this is reply dir. */ | |
505 | if (dir == IP_CT_DIR_REPLY) | |
506 | statusbit ^= IPS_NAT_MASK; | |
507 | ||
508 | if (ct->status & statusbit) { | |
509 | nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple); | |
3db05fea | 510 | if (!manip_pkt(0, skb, 0, &target, manip)) |
5b1158e9 JK |
511 | return 0; |
512 | } | |
513 | ||
514 | return 1; | |
515 | } | |
516 | EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation); | |
517 | ||
518 | /* Protocol registration. */ | |
2b628a08 | 519 | int nf_nat_protocol_register(const struct nf_nat_protocol *proto) |
5b1158e9 JK |
520 | { |
521 | int ret = 0; | |
522 | ||
523 | write_lock_bh(&nf_nat_lock); | |
524 | if (nf_nat_protos[proto->protonum] != &nf_nat_unknown_protocol) { | |
525 | ret = -EBUSY; | |
526 | goto out; | |
527 | } | |
e22a0548 | 528 | rcu_assign_pointer(nf_nat_protos[proto->protonum], proto); |
5b1158e9 JK |
529 | out: |
530 | write_unlock_bh(&nf_nat_lock); | |
531 | return ret; | |
532 | } | |
533 | EXPORT_SYMBOL(nf_nat_protocol_register); | |
534 | ||
535 | /* Noone stores the protocol anywhere; simply delete it. */ | |
2b628a08 | 536 | void nf_nat_protocol_unregister(const struct nf_nat_protocol *proto) |
5b1158e9 JK |
537 | { |
538 | write_lock_bh(&nf_nat_lock); | |
e22a0548 PM |
539 | rcu_assign_pointer(nf_nat_protos[proto->protonum], |
540 | &nf_nat_unknown_protocol); | |
5b1158e9 | 541 | write_unlock_bh(&nf_nat_lock); |
e22a0548 | 542 | synchronize_rcu(); |
5b1158e9 JK |
543 | } |
544 | EXPORT_SYMBOL(nf_nat_protocol_unregister); | |
545 | ||
e281db5c | 546 | #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
5b1158e9 | 547 | int |
fdf70832 | 548 | nf_nat_port_range_to_nlattr(struct sk_buff *skb, |
5b1158e9 JK |
549 | const struct nf_nat_range *range) |
550 | { | |
77236b6e PM |
551 | NLA_PUT_BE16(skb, CTA_PROTONAT_PORT_MIN, range->min.tcp.port); |
552 | NLA_PUT_BE16(skb, CTA_PROTONAT_PORT_MAX, range->max.tcp.port); | |
5b1158e9 JK |
553 | |
554 | return 0; | |
555 | ||
df6fb868 | 556 | nla_put_failure: |
5b1158e9 JK |
557 | return -1; |
558 | } | |
fdf70832 | 559 | EXPORT_SYMBOL_GPL(nf_nat_port_nlattr_to_range); |
5b1158e9 JK |
560 | |
561 | int | |
fdf70832 | 562 | nf_nat_port_nlattr_to_range(struct nlattr *tb[], struct nf_nat_range *range) |
5b1158e9 JK |
563 | { |
564 | int ret = 0; | |
565 | ||
566 | /* we have to return whether we actually parsed something or not */ | |
567 | ||
df6fb868 | 568 | if (tb[CTA_PROTONAT_PORT_MIN]) { |
5b1158e9 | 569 | ret = 1; |
77236b6e | 570 | range->min.tcp.port = nla_get_be16(tb[CTA_PROTONAT_PORT_MIN]); |
5b1158e9 JK |
571 | } |
572 | ||
df6fb868 | 573 | if (!tb[CTA_PROTONAT_PORT_MAX]) { |
5b1158e9 JK |
574 | if (ret) |
575 | range->max.tcp.port = range->min.tcp.port; | |
576 | } else { | |
577 | ret = 1; | |
77236b6e | 578 | range->max.tcp.port = nla_get_be16(tb[CTA_PROTONAT_PORT_MAX]); |
5b1158e9 JK |
579 | } |
580 | ||
581 | return ret; | |
582 | } | |
fdf70832 | 583 | EXPORT_SYMBOL_GPL(nf_nat_port_range_to_nlattr); |
5b1158e9 JK |
584 | #endif |
585 | ||
d8a0509a YK |
586 | /* Noone using conntrack by the time this called. */ |
587 | static void nf_nat_cleanup_conntrack(struct nf_conn *ct) | |
588 | { | |
589 | struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT); | |
590 | ||
b6b84d4a | 591 | if (nat == NULL || nat->ct == NULL) |
d8a0509a YK |
592 | return; |
593 | ||
b6b84d4a | 594 | NF_CT_ASSERT(nat->ct->status & IPS_NAT_DONE_MASK); |
d8a0509a YK |
595 | |
596 | write_lock_bh(&nf_nat_lock); | |
53aba597 | 597 | hlist_del(&nat->bysource); |
b6b84d4a | 598 | nat->ct = NULL; |
d8a0509a YK |
599 | write_unlock_bh(&nf_nat_lock); |
600 | } | |
601 | ||
2d59e5ca YK |
602 | static void nf_nat_move_storage(struct nf_conn *conntrack, void *old) |
603 | { | |
604 | struct nf_conn_nat *new_nat = nf_ct_ext_find(conntrack, NF_CT_EXT_NAT); | |
605 | struct nf_conn_nat *old_nat = (struct nf_conn_nat *)old; | |
b6b84d4a | 606 | struct nf_conn *ct = old_nat->ct; |
2d59e5ca | 607 | |
1f305323 | 608 | if (!ct || !(ct->status & IPS_NAT_DONE_MASK)) |
2d59e5ca YK |
609 | return; |
610 | ||
2d59e5ca | 611 | write_lock_bh(&nf_nat_lock); |
53aba597 | 612 | hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource); |
b6b84d4a | 613 | new_nat->ct = ct; |
2d59e5ca YK |
614 | write_unlock_bh(&nf_nat_lock); |
615 | } | |
616 | ||
61eb3107 | 617 | static struct nf_ct_ext_type nat_extend __read_mostly = { |
d8a0509a YK |
618 | .len = sizeof(struct nf_conn_nat), |
619 | .align = __alignof__(struct nf_conn_nat), | |
620 | .destroy = nf_nat_cleanup_conntrack, | |
621 | .move = nf_nat_move_storage, | |
622 | .id = NF_CT_EXT_NAT, | |
623 | .flags = NF_CT_EXT_F_PREALLOC, | |
2d59e5ca YK |
624 | }; |
625 | ||
5b1158e9 JK |
626 | static int __init nf_nat_init(void) |
627 | { | |
628 | size_t i; | |
2d59e5ca YK |
629 | int ret; |
630 | ||
631 | ret = nf_ct_extend_register(&nat_extend); | |
632 | if (ret < 0) { | |
633 | printk(KERN_ERR "nf_nat_core: Unable to register extension\n"); | |
634 | return ret; | |
635 | } | |
5b1158e9 JK |
636 | |
637 | /* Leave them the same for the moment. */ | |
638 | nf_nat_htable_size = nf_conntrack_htable_size; | |
639 | ||
53aba597 PM |
640 | bysource = nf_ct_alloc_hashtable(&nf_nat_htable_size, |
641 | &nf_nat_vmalloced); | |
2d59e5ca YK |
642 | if (!bysource) { |
643 | ret = -ENOMEM; | |
644 | goto cleanup_extend; | |
645 | } | |
5b1158e9 JK |
646 | |
647 | /* Sew in builtin protocols. */ | |
648 | write_lock_bh(&nf_nat_lock); | |
649 | for (i = 0; i < MAX_IP_NAT_PROTO; i++) | |
e22a0548 PM |
650 | rcu_assign_pointer(nf_nat_protos[i], &nf_nat_unknown_protocol); |
651 | rcu_assign_pointer(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp); | |
652 | rcu_assign_pointer(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp); | |
653 | rcu_assign_pointer(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp); | |
5b1158e9 JK |
654 | write_unlock_bh(&nf_nat_lock); |
655 | ||
656 | for (i = 0; i < nf_nat_htable_size; i++) { | |
53aba597 | 657 | INIT_HLIST_HEAD(&bysource[i]); |
5b1158e9 JK |
658 | } |
659 | ||
5b1158e9 JK |
660 | /* Initialize fake conntrack so that NAT will skip it */ |
661 | nf_conntrack_untracked.status |= IPS_NAT_DONE_MASK; | |
662 | ||
663 | l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET); | |
664 | return 0; | |
2d59e5ca YK |
665 | |
666 | cleanup_extend: | |
667 | nf_ct_extend_unregister(&nat_extend); | |
668 | return ret; | |
5b1158e9 JK |
669 | } |
670 | ||
671 | /* Clear NAT section of all conntracks, in case we're loaded again. */ | |
672 | static int clean_nat(struct nf_conn *i, void *data) | |
673 | { | |
674 | struct nf_conn_nat *nat = nfct_nat(i); | |
675 | ||
676 | if (!nat) | |
677 | return 0; | |
e0bf9cf1 | 678 | memset(nat, 0, sizeof(*nat)); |
5b1158e9 JK |
679 | i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST); |
680 | return 0; | |
681 | } | |
682 | ||
683 | static void __exit nf_nat_cleanup(void) | |
684 | { | |
685 | nf_ct_iterate_cleanup(&clean_nat, NULL); | |
982d9a9c | 686 | synchronize_rcu(); |
53aba597 | 687 | nf_ct_free_hashtable(bysource, nf_nat_vmalloced, nf_nat_htable_size); |
5b1158e9 | 688 | nf_ct_l3proto_put(l3proto); |
2d59e5ca | 689 | nf_ct_extend_unregister(&nat_extend); |
5b1158e9 JK |
690 | } |
691 | ||
692 | MODULE_LICENSE("GPL"); | |
693 | ||
694 | module_init(nf_nat_init); | |
695 | module_exit(nf_nat_cleanup); |