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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 | ||
02502f62 | 34 | static DEFINE_SPINLOCK(nf_nat_lock); |
5b1158e9 | 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; |
5b1158e9 JK |
40 | |
41 | #define MAX_IP_NAT_PROTO 256 | |
ce4b1ceb PM |
42 | static const struct nf_nat_protocol *nf_nat_protos[MAX_IP_NAT_PROTO] |
43 | __read_mostly; | |
5b1158e9 | 44 | |
2b628a08 | 45 | static inline const struct nf_nat_protocol * |
5b1158e9 JK |
46 | __nf_nat_proto_find(u_int8_t protonum) |
47 | { | |
e22a0548 | 48 | return rcu_dereference(nf_nat_protos[protonum]); |
5b1158e9 JK |
49 | } |
50 | ||
2b628a08 | 51 | const struct nf_nat_protocol * |
5b1158e9 JK |
52 | nf_nat_proto_find_get(u_int8_t protonum) |
53 | { | |
2b628a08 | 54 | const struct nf_nat_protocol *p; |
5b1158e9 | 55 | |
e22a0548 | 56 | rcu_read_lock(); |
5b1158e9 JK |
57 | p = __nf_nat_proto_find(protonum); |
58 | if (!try_module_get(p->me)) | |
59 | p = &nf_nat_unknown_protocol; | |
e22a0548 | 60 | rcu_read_unlock(); |
5b1158e9 JK |
61 | |
62 | return p; | |
63 | } | |
64 | EXPORT_SYMBOL_GPL(nf_nat_proto_find_get); | |
65 | ||
66 | void | |
2b628a08 | 67 | nf_nat_proto_put(const struct nf_nat_protocol *p) |
5b1158e9 JK |
68 | { |
69 | module_put(p->me); | |
70 | } | |
71 | EXPORT_SYMBOL_GPL(nf_nat_proto_put); | |
72 | ||
73 | /* We keep an extra hash for each conntrack, for fast searching. */ | |
74 | static inline unsigned int | |
75 | hash_by_src(const struct nf_conntrack_tuple *tuple) | |
76 | { | |
34498825 PM |
77 | unsigned int hash; |
78 | ||
5b1158e9 | 79 | /* Original src, to ensure we map it consistently if poss. */ |
34498825 | 80 | hash = jhash_3words((__force u32)tuple->src.u3.ip, |
a34c4589 | 81 | (__force u32)tuple->src.u.all, |
34498825 PM |
82 | tuple->dst.protonum, 0); |
83 | return ((u64)hash * nf_nat_htable_size) >> 32; | |
5b1158e9 JK |
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 | |
0c4c9288 AD |
145 | find_appropriate_src(struct net *net, |
146 | const struct nf_conntrack_tuple *tuple, | |
5b1158e9 JK |
147 | struct nf_conntrack_tuple *result, |
148 | const struct nf_nat_range *range) | |
149 | { | |
150 | unsigned int h = hash_by_src(tuple); | |
72b72949 JE |
151 | const struct nf_conn_nat *nat; |
152 | const struct nf_conn *ct; | |
153 | const struct hlist_node *n; | |
5b1158e9 | 154 | |
4d354c57 | 155 | rcu_read_lock(); |
0c4c9288 | 156 | hlist_for_each_entry_rcu(nat, n, &net->ipv4.nat_bysource[h], bysource) { |
b6b84d4a | 157 | ct = nat->ct; |
5b1158e9 JK |
158 | if (same_src(ct, tuple)) { |
159 | /* Copy source part from reply tuple. */ | |
160 | nf_ct_invert_tuplepr(result, | |
161 | &ct->tuplehash[IP_CT_DIR_REPLY].tuple); | |
162 | result->dst = tuple->dst; | |
163 | ||
164 | if (in_range(result, range)) { | |
4d354c57 | 165 | rcu_read_unlock(); |
5b1158e9 JK |
166 | return 1; |
167 | } | |
168 | } | |
169 | } | |
4d354c57 | 170 | rcu_read_unlock(); |
5b1158e9 JK |
171 | return 0; |
172 | } | |
173 | ||
174 | /* For [FUTURE] fragmentation handling, we want the least-used | |
175 | src-ip/dst-ip/proto triple. Fairness doesn't come into it. Thus | |
176 | if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports | |
177 | 1-65535, we don't do pro-rata allocation based on ports; we choose | |
178 | the ip with the lowest src-ip/dst-ip/proto usage. | |
179 | */ | |
180 | static void | |
181 | find_best_ips_proto(struct nf_conntrack_tuple *tuple, | |
182 | const struct nf_nat_range *range, | |
183 | const struct nf_conn *ct, | |
184 | enum nf_nat_manip_type maniptype) | |
185 | { | |
186 | __be32 *var_ipp; | |
187 | /* Host order */ | |
188 | u_int32_t minip, maxip, j; | |
189 | ||
190 | /* No IP mapping? Do nothing. */ | |
191 | if (!(range->flags & IP_NAT_RANGE_MAP_IPS)) | |
192 | return; | |
193 | ||
194 | if (maniptype == IP_NAT_MANIP_SRC) | |
195 | var_ipp = &tuple->src.u3.ip; | |
196 | else | |
197 | var_ipp = &tuple->dst.u3.ip; | |
198 | ||
199 | /* Fast path: only one choice. */ | |
200 | if (range->min_ip == range->max_ip) { | |
201 | *var_ipp = range->min_ip; | |
202 | return; | |
203 | } | |
204 | ||
205 | /* Hashing source and destination IPs gives a fairly even | |
206 | * spread in practice (if there are a small number of IPs | |
207 | * involved, there usually aren't that many connections | |
208 | * anyway). The consistency means that servers see the same | |
209 | * client coming from the same IP (some Internet Banking sites | |
210 | * like this), even across reboots. */ | |
211 | minip = ntohl(range->min_ip); | |
212 | maxip = ntohl(range->max_ip); | |
213 | j = jhash_2words((__force u32)tuple->src.u3.ip, | |
98d500d6 | 214 | range->flags & IP_NAT_RANGE_PERSISTENT ? |
cce5a5c3 | 215 | 0 : (__force u32)tuple->dst.u3.ip, 0); |
34498825 PM |
216 | j = ((u64)j * (maxip - minip + 1)) >> 32; |
217 | *var_ipp = htonl(minip + j); | |
5b1158e9 JK |
218 | } |
219 | ||
6e23ae2a PM |
220 | /* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING, |
221 | * we change the source to map into the range. For NF_INET_PRE_ROUTING | |
222 | * and NF_INET_LOCAL_OUT, we change the destination to map into the | |
5b1158e9 JK |
223 | * range. It might not be possible to get a unique tuple, but we try. |
224 | * At worst (or if we race), we will end up with a final duplicate in | |
225 | * __ip_conntrack_confirm and drop the packet. */ | |
226 | static void | |
227 | get_unique_tuple(struct nf_conntrack_tuple *tuple, | |
228 | const struct nf_conntrack_tuple *orig_tuple, | |
229 | const struct nf_nat_range *range, | |
230 | struct nf_conn *ct, | |
231 | enum nf_nat_manip_type maniptype) | |
232 | { | |
0c4c9288 | 233 | struct net *net = nf_ct_net(ct); |
2b628a08 | 234 | const struct nf_nat_protocol *proto; |
5b1158e9 JK |
235 | |
236 | /* 1) If this srcip/proto/src-proto-part is currently mapped, | |
237 | and that same mapping gives a unique tuple within the given | |
238 | range, use that. | |
239 | ||
240 | This is only required for source (ie. NAT/masq) mappings. | |
241 | So far, we don't do local source mappings, so multiple | |
242 | manips not an issue. */ | |
0dbff689 CG |
243 | if (maniptype == IP_NAT_MANIP_SRC && |
244 | !(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) { | |
0c4c9288 | 245 | if (find_appropriate_src(net, orig_tuple, tuple, range)) { |
0d53778e | 246 | pr_debug("get_unique_tuple: Found current src map\n"); |
0dbff689 CG |
247 | if (!nf_nat_used_tuple(tuple, ct)) |
248 | return; | |
5b1158e9 JK |
249 | } |
250 | } | |
251 | ||
252 | /* 2) Select the least-used IP/proto combination in the given | |
253 | range. */ | |
254 | *tuple = *orig_tuple; | |
255 | find_best_ips_proto(tuple, range, ct, maniptype); | |
256 | ||
257 | /* 3) The per-protocol part of the manip is made to map into | |
258 | the range to make a unique tuple. */ | |
259 | ||
e22a0548 PM |
260 | rcu_read_lock(); |
261 | proto = __nf_nat_proto_find(orig_tuple->dst.protonum); | |
5b1158e9 | 262 | |
41f4689a EL |
263 | /* Change protocol info to have some randomization */ |
264 | if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) { | |
265 | proto->unique_tuple(tuple, range, maniptype, ct); | |
e22a0548 | 266 | goto out; |
41f4689a EL |
267 | } |
268 | ||
5b1158e9 JK |
269 | /* Only bother mapping if it's not already in range and unique */ |
270 | if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) || | |
271 | proto->in_range(tuple, maniptype, &range->min, &range->max)) && | |
e22a0548 PM |
272 | !nf_nat_used_tuple(tuple, ct)) |
273 | goto out; | |
5b1158e9 JK |
274 | |
275 | /* Last change: get protocol to try to obtain unique tuple. */ | |
276 | proto->unique_tuple(tuple, range, maniptype, ct); | |
e22a0548 PM |
277 | out: |
278 | rcu_read_unlock(); | |
5b1158e9 JK |
279 | } |
280 | ||
281 | unsigned int | |
282 | nf_nat_setup_info(struct nf_conn *ct, | |
283 | const struct nf_nat_range *range, | |
cc01dcbd | 284 | enum nf_nat_manip_type maniptype) |
5b1158e9 | 285 | { |
0c4c9288 | 286 | struct net *net = nf_ct_net(ct); |
5b1158e9 | 287 | struct nf_conntrack_tuple curr_tuple, new_tuple; |
2d59e5ca | 288 | struct nf_conn_nat *nat; |
5b1158e9 | 289 | int have_to_hash = !(ct->status & IPS_NAT_DONE_MASK); |
5b1158e9 | 290 | |
2d59e5ca YK |
291 | /* nat helper or nfctnetlink also setup binding */ |
292 | nat = nfct_nat(ct); | |
293 | if (!nat) { | |
294 | nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC); | |
295 | if (nat == NULL) { | |
0d53778e | 296 | pr_debug("failed to add NAT extension\n"); |
2d59e5ca YK |
297 | return NF_ACCEPT; |
298 | } | |
299 | } | |
300 | ||
cc01dcbd PM |
301 | NF_CT_ASSERT(maniptype == IP_NAT_MANIP_SRC || |
302 | maniptype == IP_NAT_MANIP_DST); | |
5b1158e9 JK |
303 | BUG_ON(nf_nat_initialized(ct, maniptype)); |
304 | ||
305 | /* What we've got will look like inverse of reply. Normally | |
306 | this is what is in the conntrack, except for prior | |
307 | manipulations (future optimization: if num_manips == 0, | |
308 | orig_tp = | |
309 | conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */ | |
310 | nf_ct_invert_tuplepr(&curr_tuple, | |
311 | &ct->tuplehash[IP_CT_DIR_REPLY].tuple); | |
312 | ||
313 | get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype); | |
314 | ||
315 | if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) { | |
316 | struct nf_conntrack_tuple reply; | |
317 | ||
318 | /* Alter conntrack table so will recognize replies. */ | |
319 | nf_ct_invert_tuplepr(&reply, &new_tuple); | |
320 | nf_conntrack_alter_reply(ct, &reply); | |
321 | ||
322 | /* Non-atomic: we own this at the moment. */ | |
323 | if (maniptype == IP_NAT_MANIP_SRC) | |
324 | ct->status |= IPS_SRC_NAT; | |
325 | else | |
326 | ct->status |= IPS_DST_NAT; | |
327 | } | |
328 | ||
329 | /* Place in source hash if this is the first time. */ | |
330 | if (have_to_hash) { | |
331 | unsigned int srchash; | |
332 | ||
333 | srchash = hash_by_src(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); | |
02502f62 | 334 | spin_lock_bh(&nf_nat_lock); |
2d59e5ca | 335 | /* nf_conntrack_alter_reply might re-allocate exntension aera */ |
b6b84d4a YK |
336 | nat = nfct_nat(ct); |
337 | nat->ct = ct; | |
0c4c9288 AD |
338 | hlist_add_head_rcu(&nat->bysource, |
339 | &net->ipv4.nat_bysource[srchash]); | |
02502f62 | 340 | spin_unlock_bh(&nf_nat_lock); |
5b1158e9 JK |
341 | } |
342 | ||
343 | /* It's done. */ | |
344 | if (maniptype == IP_NAT_MANIP_DST) | |
345 | set_bit(IPS_DST_NAT_DONE_BIT, &ct->status); | |
346 | else | |
347 | set_bit(IPS_SRC_NAT_DONE_BIT, &ct->status); | |
348 | ||
349 | return NF_ACCEPT; | |
350 | } | |
351 | EXPORT_SYMBOL(nf_nat_setup_info); | |
352 | ||
353 | /* Returns true if succeeded. */ | |
f2ea825f | 354 | static bool |
5b1158e9 | 355 | manip_pkt(u_int16_t proto, |
3db05fea | 356 | struct sk_buff *skb, |
5b1158e9 JK |
357 | unsigned int iphdroff, |
358 | const struct nf_conntrack_tuple *target, | |
359 | enum nf_nat_manip_type maniptype) | |
360 | { | |
361 | struct iphdr *iph; | |
2b628a08 | 362 | const struct nf_nat_protocol *p; |
5b1158e9 | 363 | |
3db05fea | 364 | if (!skb_make_writable(skb, iphdroff + sizeof(*iph))) |
f2ea825f | 365 | return false; |
5b1158e9 | 366 | |
3db05fea | 367 | iph = (void *)skb->data + iphdroff; |
5b1158e9 JK |
368 | |
369 | /* Manipulate protcol part. */ | |
e22a0548 PM |
370 | |
371 | /* rcu_read_lock()ed by nf_hook_slow */ | |
372 | p = __nf_nat_proto_find(proto); | |
3db05fea | 373 | if (!p->manip_pkt(skb, iphdroff, target, maniptype)) |
f2ea825f | 374 | return false; |
5b1158e9 | 375 | |
3db05fea | 376 | iph = (void *)skb->data + iphdroff; |
5b1158e9 JK |
377 | |
378 | if (maniptype == IP_NAT_MANIP_SRC) { | |
be0ea7d5 | 379 | csum_replace4(&iph->check, iph->saddr, target->src.u3.ip); |
5b1158e9 JK |
380 | iph->saddr = target->src.u3.ip; |
381 | } else { | |
be0ea7d5 | 382 | csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip); |
5b1158e9 JK |
383 | iph->daddr = target->dst.u3.ip; |
384 | } | |
f2ea825f | 385 | return true; |
5b1158e9 JK |
386 | } |
387 | ||
388 | /* Do packet manipulations according to nf_nat_setup_info. */ | |
389 | unsigned int nf_nat_packet(struct nf_conn *ct, | |
390 | enum ip_conntrack_info ctinfo, | |
391 | unsigned int hooknum, | |
3db05fea | 392 | struct sk_buff *skb) |
5b1158e9 JK |
393 | { |
394 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); | |
395 | unsigned long statusbit; | |
396 | enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum); | |
397 | ||
398 | if (mtype == IP_NAT_MANIP_SRC) | |
399 | statusbit = IPS_SRC_NAT; | |
400 | else | |
401 | statusbit = IPS_DST_NAT; | |
402 | ||
403 | /* Invert if this is reply dir. */ | |
404 | if (dir == IP_CT_DIR_REPLY) | |
405 | statusbit ^= IPS_NAT_MASK; | |
406 | ||
407 | /* Non-atomic: these bits don't change. */ | |
408 | if (ct->status & statusbit) { | |
409 | struct nf_conntrack_tuple target; | |
410 | ||
411 | /* We are aiming to look like inverse of other direction. */ | |
412 | nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple); | |
413 | ||
3db05fea | 414 | if (!manip_pkt(target.dst.protonum, skb, 0, &target, mtype)) |
5b1158e9 JK |
415 | return NF_DROP; |
416 | } | |
417 | return NF_ACCEPT; | |
418 | } | |
419 | EXPORT_SYMBOL_GPL(nf_nat_packet); | |
420 | ||
421 | /* Dir is direction ICMP is coming from (opposite to packet it contains) */ | |
422 | int nf_nat_icmp_reply_translation(struct nf_conn *ct, | |
423 | enum ip_conntrack_info ctinfo, | |
424 | unsigned int hooknum, | |
3db05fea | 425 | struct sk_buff *skb) |
5b1158e9 JK |
426 | { |
427 | struct { | |
428 | struct icmphdr icmp; | |
429 | struct iphdr ip; | |
430 | } *inside; | |
72b72949 | 431 | const struct nf_conntrack_l4proto *l4proto; |
5b1158e9 | 432 | struct nf_conntrack_tuple inner, target; |
3db05fea | 433 | int hdrlen = ip_hdrlen(skb); |
5b1158e9 JK |
434 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
435 | unsigned long statusbit; | |
436 | enum nf_nat_manip_type manip = HOOK2MANIP(hooknum); | |
437 | ||
3db05fea | 438 | if (!skb_make_writable(skb, hdrlen + sizeof(*inside))) |
5b1158e9 JK |
439 | return 0; |
440 | ||
3db05fea | 441 | inside = (void *)skb->data + ip_hdrlen(skb); |
5b1158e9 JK |
442 | |
443 | /* We're actually going to mangle it beyond trivial checksum | |
444 | adjustment, so make sure the current checksum is correct. */ | |
3db05fea | 445 | if (nf_ip_checksum(skb, hooknum, hdrlen, 0)) |
5b1158e9 JK |
446 | return 0; |
447 | ||
448 | /* Must be RELATED */ | |
3db05fea HX |
449 | NF_CT_ASSERT(skb->nfctinfo == IP_CT_RELATED || |
450 | skb->nfctinfo == IP_CT_RELATED+IP_CT_IS_REPLY); | |
5b1158e9 JK |
451 | |
452 | /* Redirects on non-null nats must be dropped, else they'll | |
e905a9ed YH |
453 | start talking to each other without our translation, and be |
454 | confused... --RR */ | |
5b1158e9 JK |
455 | if (inside->icmp.type == ICMP_REDIRECT) { |
456 | /* If NAT isn't finished, assume it and drop. */ | |
457 | if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK) | |
458 | return 0; | |
459 | ||
460 | if (ct->status & IPS_NAT_MASK) | |
461 | return 0; | |
462 | } | |
463 | ||
0d53778e | 464 | pr_debug("icmp_reply_translation: translating error %p manip %u " |
3db05fea | 465 | "dir %s\n", skb, manip, |
0d53778e | 466 | dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY"); |
5b1158e9 | 467 | |
923f4902 PM |
468 | /* rcu_read_lock()ed by nf_hook_slow */ |
469 | l4proto = __nf_ct_l4proto_find(PF_INET, inside->ip.protocol); | |
470 | ||
3db05fea HX |
471 | if (!nf_ct_get_tuple(skb, |
472 | ip_hdrlen(skb) + sizeof(struct icmphdr), | |
473 | (ip_hdrlen(skb) + | |
c9bdd4b5 | 474 | sizeof(struct icmphdr) + inside->ip.ihl * 4), |
e905a9ed YH |
475 | (u_int16_t)AF_INET, |
476 | inside->ip.protocol, | |
923f4902 | 477 | &inner, l3proto, l4proto)) |
5b1158e9 JK |
478 | return 0; |
479 | ||
480 | /* Change inner back to look like incoming packet. We do the | |
481 | opposite manip on this hook to normal, because it might not | |
482 | pass all hooks (locally-generated ICMP). Consider incoming | |
483 | packet: PREROUTING (DST manip), routing produces ICMP, goes | |
484 | through POSTROUTING (which must correct the DST manip). */ | |
3db05fea HX |
485 | if (!manip_pkt(inside->ip.protocol, skb, |
486 | ip_hdrlen(skb) + sizeof(inside->icmp), | |
5b1158e9 JK |
487 | &ct->tuplehash[!dir].tuple, |
488 | !manip)) | |
489 | return 0; | |
490 | ||
3db05fea | 491 | if (skb->ip_summed != CHECKSUM_PARTIAL) { |
5b1158e9 | 492 | /* Reloading "inside" here since manip_pkt inner. */ |
3db05fea | 493 | inside = (void *)skb->data + ip_hdrlen(skb); |
5b1158e9 JK |
494 | inside->icmp.checksum = 0; |
495 | inside->icmp.checksum = | |
3db05fea HX |
496 | csum_fold(skb_checksum(skb, hdrlen, |
497 | skb->len - hdrlen, 0)); | |
5b1158e9 JK |
498 | } |
499 | ||
500 | /* Change outer to look the reply to an incoming packet | |
501 | * (proto 0 means don't invert per-proto part). */ | |
502 | if (manip == IP_NAT_MANIP_SRC) | |
503 | statusbit = IPS_SRC_NAT; | |
504 | else | |
505 | statusbit = IPS_DST_NAT; | |
506 | ||
507 | /* Invert if this is reply dir. */ | |
508 | if (dir == IP_CT_DIR_REPLY) | |
509 | statusbit ^= IPS_NAT_MASK; | |
510 | ||
511 | if (ct->status & statusbit) { | |
512 | nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple); | |
3db05fea | 513 | if (!manip_pkt(0, skb, 0, &target, manip)) |
5b1158e9 JK |
514 | return 0; |
515 | } | |
516 | ||
517 | return 1; | |
518 | } | |
519 | EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation); | |
520 | ||
521 | /* Protocol registration. */ | |
2b628a08 | 522 | int nf_nat_protocol_register(const struct nf_nat_protocol *proto) |
5b1158e9 JK |
523 | { |
524 | int ret = 0; | |
525 | ||
02502f62 | 526 | spin_lock_bh(&nf_nat_lock); |
5b1158e9 JK |
527 | if (nf_nat_protos[proto->protonum] != &nf_nat_unknown_protocol) { |
528 | ret = -EBUSY; | |
529 | goto out; | |
530 | } | |
e22a0548 | 531 | rcu_assign_pointer(nf_nat_protos[proto->protonum], proto); |
5b1158e9 | 532 | out: |
02502f62 | 533 | spin_unlock_bh(&nf_nat_lock); |
5b1158e9 JK |
534 | return ret; |
535 | } | |
536 | EXPORT_SYMBOL(nf_nat_protocol_register); | |
537 | ||
538 | /* Noone stores the protocol anywhere; simply delete it. */ | |
2b628a08 | 539 | void nf_nat_protocol_unregister(const struct nf_nat_protocol *proto) |
5b1158e9 | 540 | { |
02502f62 | 541 | spin_lock_bh(&nf_nat_lock); |
e22a0548 PM |
542 | rcu_assign_pointer(nf_nat_protos[proto->protonum], |
543 | &nf_nat_unknown_protocol); | |
02502f62 | 544 | spin_unlock_bh(&nf_nat_lock); |
e22a0548 | 545 | synchronize_rcu(); |
5b1158e9 JK |
546 | } |
547 | EXPORT_SYMBOL(nf_nat_protocol_unregister); | |
548 | ||
d8a0509a YK |
549 | /* Noone using conntrack by the time this called. */ |
550 | static void nf_nat_cleanup_conntrack(struct nf_conn *ct) | |
551 | { | |
552 | struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT); | |
553 | ||
b6b84d4a | 554 | if (nat == NULL || nat->ct == NULL) |
d8a0509a YK |
555 | return; |
556 | ||
b6b84d4a | 557 | NF_CT_ASSERT(nat->ct->status & IPS_NAT_DONE_MASK); |
d8a0509a | 558 | |
02502f62 | 559 | spin_lock_bh(&nf_nat_lock); |
4d354c57 | 560 | hlist_del_rcu(&nat->bysource); |
02502f62 | 561 | spin_unlock_bh(&nf_nat_lock); |
d8a0509a YK |
562 | } |
563 | ||
86577c66 | 564 | static void nf_nat_move_storage(void *new, void *old) |
2d59e5ca | 565 | { |
86577c66 PM |
566 | struct nf_conn_nat *new_nat = new; |
567 | struct nf_conn_nat *old_nat = old; | |
b6b84d4a | 568 | struct nf_conn *ct = old_nat->ct; |
2d59e5ca | 569 | |
1f305323 | 570 | if (!ct || !(ct->status & IPS_NAT_DONE_MASK)) |
2d59e5ca YK |
571 | return; |
572 | ||
02502f62 | 573 | spin_lock_bh(&nf_nat_lock); |
b6b84d4a | 574 | new_nat->ct = ct; |
68b80f11 | 575 | hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource); |
02502f62 | 576 | spin_unlock_bh(&nf_nat_lock); |
2d59e5ca YK |
577 | } |
578 | ||
61eb3107 | 579 | static struct nf_ct_ext_type nat_extend __read_mostly = { |
d8a0509a YK |
580 | .len = sizeof(struct nf_conn_nat), |
581 | .align = __alignof__(struct nf_conn_nat), | |
582 | .destroy = nf_nat_cleanup_conntrack, | |
583 | .move = nf_nat_move_storage, | |
584 | .id = NF_CT_EXT_NAT, | |
585 | .flags = NF_CT_EXT_F_PREALLOC, | |
2d59e5ca YK |
586 | }; |
587 | ||
e6a7d3c0 PNA |
588 | #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
589 | ||
590 | #include <linux/netfilter/nfnetlink.h> | |
591 | #include <linux/netfilter/nfnetlink_conntrack.h> | |
592 | ||
593 | static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = { | |
594 | [CTA_PROTONAT_PORT_MIN] = { .type = NLA_U16 }, | |
595 | [CTA_PROTONAT_PORT_MAX] = { .type = NLA_U16 }, | |
596 | }; | |
597 | ||
598 | static int nfnetlink_parse_nat_proto(struct nlattr *attr, | |
599 | const struct nf_conn *ct, | |
600 | struct nf_nat_range *range) | |
601 | { | |
602 | struct nlattr *tb[CTA_PROTONAT_MAX+1]; | |
603 | const struct nf_nat_protocol *npt; | |
604 | int err; | |
605 | ||
606 | err = nla_parse_nested(tb, CTA_PROTONAT_MAX, attr, protonat_nla_policy); | |
607 | if (err < 0) | |
608 | return err; | |
609 | ||
610 | npt = nf_nat_proto_find_get(nf_ct_protonum(ct)); | |
611 | if (npt->nlattr_to_range) | |
612 | err = npt->nlattr_to_range(tb, range); | |
613 | nf_nat_proto_put(npt); | |
614 | return err; | |
615 | } | |
616 | ||
617 | static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = { | |
618 | [CTA_NAT_MINIP] = { .type = NLA_U32 }, | |
619 | [CTA_NAT_MAXIP] = { .type = NLA_U32 }, | |
620 | }; | |
621 | ||
622 | static int | |
623 | nfnetlink_parse_nat(struct nlattr *nat, | |
624 | const struct nf_conn *ct, struct nf_nat_range *range) | |
625 | { | |
626 | struct nlattr *tb[CTA_NAT_MAX+1]; | |
627 | int err; | |
628 | ||
629 | memset(range, 0, sizeof(*range)); | |
630 | ||
631 | err = nla_parse_nested(tb, CTA_NAT_MAX, nat, nat_nla_policy); | |
632 | if (err < 0) | |
633 | return err; | |
634 | ||
635 | if (tb[CTA_NAT_MINIP]) | |
636 | range->min_ip = nla_get_be32(tb[CTA_NAT_MINIP]); | |
637 | ||
638 | if (!tb[CTA_NAT_MAXIP]) | |
639 | range->max_ip = range->min_ip; | |
640 | else | |
641 | range->max_ip = nla_get_be32(tb[CTA_NAT_MAXIP]); | |
642 | ||
643 | if (range->min_ip) | |
644 | range->flags |= IP_NAT_RANGE_MAP_IPS; | |
645 | ||
646 | if (!tb[CTA_NAT_PROTO]) | |
647 | return 0; | |
648 | ||
649 | err = nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range); | |
650 | if (err < 0) | |
651 | return err; | |
652 | ||
653 | return 0; | |
654 | } | |
655 | ||
656 | static int | |
657 | nfnetlink_parse_nat_setup(struct nf_conn *ct, | |
658 | enum nf_nat_manip_type manip, | |
659 | struct nlattr *attr) | |
660 | { | |
661 | struct nf_nat_range range; | |
662 | ||
663 | if (nfnetlink_parse_nat(attr, ct, &range) < 0) | |
664 | return -EINVAL; | |
665 | if (nf_nat_initialized(ct, manip)) | |
666 | return -EEXIST; | |
667 | ||
668 | return nf_nat_setup_info(ct, &range, manip); | |
669 | } | |
670 | #else | |
671 | static int | |
672 | nfnetlink_parse_nat_setup(struct nf_conn *ct, | |
673 | enum nf_nat_manip_type manip, | |
674 | struct nlattr *attr) | |
675 | { | |
676 | return -EOPNOTSUPP; | |
677 | } | |
678 | #endif | |
679 | ||
0c4c9288 AD |
680 | static int __net_init nf_nat_net_init(struct net *net) |
681 | { | |
682 | net->ipv4.nat_bysource = nf_ct_alloc_hashtable(&nf_nat_htable_size, | |
ea781f19 | 683 | &net->ipv4.nat_vmalloced, 0); |
0c4c9288 AD |
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. */ | |
690 | static 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 | ||
701 | static 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 | nf_nat_htable_size); | |
707 | } | |
708 | ||
709 | static struct pernet_operations nf_nat_net_ops = { | |
710 | .init = nf_nat_net_init, | |
711 | .exit = nf_nat_net_exit, | |
712 | }; | |
713 | ||
5b1158e9 JK |
714 | static int __init nf_nat_init(void) |
715 | { | |
716 | size_t i; | |
2d59e5ca YK |
717 | int ret; |
718 | ||
475959d4 JE |
719 | need_ipv4_conntrack(); |
720 | ||
2d59e5ca YK |
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 | } | |
5b1158e9 JK |
726 | |
727 | /* Leave them the same for the moment. */ | |
728 | nf_nat_htable_size = nf_conntrack_htable_size; | |
729 | ||
0c4c9288 AD |
730 | ret = register_pernet_subsys(&nf_nat_net_ops); |
731 | if (ret < 0) | |
2d59e5ca | 732 | goto cleanup_extend; |
5b1158e9 JK |
733 | |
734 | /* Sew in builtin protocols. */ | |
02502f62 | 735 | spin_lock_bh(&nf_nat_lock); |
5b1158e9 | 736 | for (i = 0; i < MAX_IP_NAT_PROTO; i++) |
e22a0548 PM |
737 | rcu_assign_pointer(nf_nat_protos[i], &nf_nat_unknown_protocol); |
738 | rcu_assign_pointer(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp); | |
739 | rcu_assign_pointer(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp); | |
740 | rcu_assign_pointer(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp); | |
02502f62 | 741 | spin_unlock_bh(&nf_nat_lock); |
5b1158e9 | 742 | |
5b1158e9 JK |
743 | /* Initialize fake conntrack so that NAT will skip it */ |
744 | nf_conntrack_untracked.status |= IPS_NAT_DONE_MASK; | |
745 | ||
746 | l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET); | |
dd13b010 PM |
747 | |
748 | BUG_ON(nf_nat_seq_adjust_hook != NULL); | |
749 | rcu_assign_pointer(nf_nat_seq_adjust_hook, nf_nat_seq_adjust); | |
e6a7d3c0 PNA |
750 | BUG_ON(nfnetlink_parse_nat_setup_hook != NULL); |
751 | rcu_assign_pointer(nfnetlink_parse_nat_setup_hook, | |
752 | nfnetlink_parse_nat_setup); | |
5b1158e9 | 753 | return 0; |
2d59e5ca YK |
754 | |
755 | cleanup_extend: | |
756 | nf_ct_extend_unregister(&nat_extend); | |
757 | return ret; | |
5b1158e9 JK |
758 | } |
759 | ||
5b1158e9 JK |
760 | static void __exit nf_nat_cleanup(void) |
761 | { | |
0c4c9288 | 762 | unregister_pernet_subsys(&nf_nat_net_ops); |
5b1158e9 | 763 | nf_ct_l3proto_put(l3proto); |
2d59e5ca | 764 | nf_ct_extend_unregister(&nat_extend); |
dd13b010 | 765 | rcu_assign_pointer(nf_nat_seq_adjust_hook, NULL); |
e6a7d3c0 | 766 | rcu_assign_pointer(nfnetlink_parse_nat_setup_hook, NULL); |
dd13b010 | 767 | synchronize_net(); |
5b1158e9 JK |
768 | } |
769 | ||
770 | MODULE_LICENSE("GPL"); | |
e6a7d3c0 | 771 | MODULE_ALIAS("nf-nat-ipv4"); |
5b1158e9 JK |
772 | |
773 | module_init(nf_nat_init); | |
774 | module_exit(nf_nat_cleanup); |