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 | 37 | |
5b1158e9 | 38 | #define MAX_IP_NAT_PROTO 256 |
ce4b1ceb PM |
39 | static const struct nf_nat_protocol *nf_nat_protos[MAX_IP_NAT_PROTO] |
40 | __read_mostly; | |
5b1158e9 | 41 | |
2b628a08 | 42 | static inline const struct nf_nat_protocol * |
5b1158e9 JK |
43 | __nf_nat_proto_find(u_int8_t protonum) |
44 | { | |
e22a0548 | 45 | return rcu_dereference(nf_nat_protos[protonum]); |
5b1158e9 JK |
46 | } |
47 | ||
2b628a08 | 48 | const struct nf_nat_protocol * |
5b1158e9 JK |
49 | nf_nat_proto_find_get(u_int8_t protonum) |
50 | { | |
2b628a08 | 51 | const struct nf_nat_protocol *p; |
5b1158e9 | 52 | |
e22a0548 | 53 | rcu_read_lock(); |
5b1158e9 JK |
54 | p = __nf_nat_proto_find(protonum); |
55 | if (!try_module_get(p->me)) | |
56 | p = &nf_nat_unknown_protocol; | |
e22a0548 | 57 | rcu_read_unlock(); |
5b1158e9 JK |
58 | |
59 | return p; | |
60 | } | |
61 | EXPORT_SYMBOL_GPL(nf_nat_proto_find_get); | |
62 | ||
63 | void | |
2b628a08 | 64 | nf_nat_proto_put(const struct nf_nat_protocol *p) |
5b1158e9 JK |
65 | { |
66 | module_put(p->me); | |
67 | } | |
68 | EXPORT_SYMBOL_GPL(nf_nat_proto_put); | |
69 | ||
70 | /* We keep an extra hash for each conntrack, for fast searching. */ | |
71 | static inline unsigned int | |
d696c7bd | 72 | hash_by_src(const struct net *net, const struct nf_conntrack_tuple *tuple) |
5b1158e9 | 73 | { |
34498825 PM |
74 | unsigned int hash; |
75 | ||
5b1158e9 | 76 | /* Original src, to ensure we map it consistently if poss. */ |
34498825 | 77 | hash = jhash_3words((__force u32)tuple->src.u3.ip, |
a34c4589 | 78 | (__force u32)tuple->src.u.all, |
34498825 | 79 | tuple->dst.protonum, 0); |
d696c7bd | 80 | return ((u64)hash * net->ipv4.nat_htable_size) >> 32; |
5b1158e9 JK |
81 | } |
82 | ||
5b1158e9 JK |
83 | /* Is this tuple already taken? (not by us) */ |
84 | int | |
85 | nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple, | |
86 | const struct nf_conn *ignored_conntrack) | |
87 | { | |
88 | /* Conntrack tracking doesn't keep track of outgoing tuples; only | |
89 | incoming ones. NAT means they don't have a fixed mapping, | |
90 | so we invert the tuple and look for the incoming reply. | |
91 | ||
92 | We could keep a separate hash if this proves too slow. */ | |
93 | struct nf_conntrack_tuple reply; | |
94 | ||
95 | nf_ct_invert_tuplepr(&reply, tuple); | |
96 | return nf_conntrack_tuple_taken(&reply, ignored_conntrack); | |
97 | } | |
98 | EXPORT_SYMBOL(nf_nat_used_tuple); | |
99 | ||
100 | /* If we source map this tuple so reply looks like reply_tuple, will | |
101 | * that meet the constraints of range. */ | |
102 | static int | |
103 | in_range(const struct nf_conntrack_tuple *tuple, | |
104 | const struct nf_nat_range *range) | |
105 | { | |
2b628a08 | 106 | const struct nf_nat_protocol *proto; |
e22a0548 | 107 | int ret = 0; |
5b1158e9 | 108 | |
5b1158e9 JK |
109 | /* If we are supposed to map IPs, then we must be in the |
110 | range specified, otherwise let this drag us onto a new src IP. */ | |
111 | if (range->flags & IP_NAT_RANGE_MAP_IPS) { | |
112 | if (ntohl(tuple->src.u3.ip) < ntohl(range->min_ip) || | |
113 | ntohl(tuple->src.u3.ip) > ntohl(range->max_ip)) | |
114 | return 0; | |
115 | } | |
116 | ||
e22a0548 PM |
117 | rcu_read_lock(); |
118 | proto = __nf_nat_proto_find(tuple->dst.protonum); | |
5b1158e9 JK |
119 | if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) || |
120 | proto->in_range(tuple, IP_NAT_MANIP_SRC, | |
121 | &range->min, &range->max)) | |
e22a0548 PM |
122 | ret = 1; |
123 | rcu_read_unlock(); | |
5b1158e9 | 124 | |
e22a0548 | 125 | return ret; |
5b1158e9 JK |
126 | } |
127 | ||
128 | static inline int | |
129 | same_src(const struct nf_conn *ct, | |
130 | const struct nf_conntrack_tuple *tuple) | |
131 | { | |
132 | const struct nf_conntrack_tuple *t; | |
133 | ||
134 | t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; | |
135 | return (t->dst.protonum == tuple->dst.protonum && | |
136 | t->src.u3.ip == tuple->src.u3.ip && | |
137 | t->src.u.all == tuple->src.u.all); | |
138 | } | |
139 | ||
140 | /* Only called for SRC manip */ | |
141 | static int | |
0c4c9288 AD |
142 | find_appropriate_src(struct net *net, |
143 | const struct nf_conntrack_tuple *tuple, | |
5b1158e9 JK |
144 | struct nf_conntrack_tuple *result, |
145 | const struct nf_nat_range *range) | |
146 | { | |
d696c7bd | 147 | unsigned int h = hash_by_src(net, tuple); |
72b72949 JE |
148 | const struct nf_conn_nat *nat; |
149 | const struct nf_conn *ct; | |
150 | const struct hlist_node *n; | |
5b1158e9 | 151 | |
4d354c57 | 152 | rcu_read_lock(); |
0c4c9288 | 153 | hlist_for_each_entry_rcu(nat, n, &net->ipv4.nat_bysource[h], bysource) { |
b6b84d4a | 154 | ct = nat->ct; |
5b1158e9 JK |
155 | if (same_src(ct, tuple)) { |
156 | /* Copy source part from reply tuple. */ | |
157 | nf_ct_invert_tuplepr(result, | |
158 | &ct->tuplehash[IP_CT_DIR_REPLY].tuple); | |
159 | result->dst = tuple->dst; | |
160 | ||
161 | if (in_range(result, range)) { | |
4d354c57 | 162 | rcu_read_unlock(); |
5b1158e9 JK |
163 | return 1; |
164 | } | |
165 | } | |
166 | } | |
4d354c57 | 167 | rcu_read_unlock(); |
5b1158e9 JK |
168 | return 0; |
169 | } | |
170 | ||
171 | /* For [FUTURE] fragmentation handling, we want the least-used | |
172 | src-ip/dst-ip/proto triple. Fairness doesn't come into it. Thus | |
173 | if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports | |
174 | 1-65535, we don't do pro-rata allocation based on ports; we choose | |
175 | the ip with the lowest src-ip/dst-ip/proto usage. | |
176 | */ | |
177 | static void | |
178 | find_best_ips_proto(struct nf_conntrack_tuple *tuple, | |
179 | const struct nf_nat_range *range, | |
180 | const struct nf_conn *ct, | |
181 | enum nf_nat_manip_type maniptype) | |
182 | { | |
183 | __be32 *var_ipp; | |
184 | /* Host order */ | |
185 | u_int32_t minip, maxip, j; | |
186 | ||
187 | /* No IP mapping? Do nothing. */ | |
188 | if (!(range->flags & IP_NAT_RANGE_MAP_IPS)) | |
189 | return; | |
190 | ||
191 | if (maniptype == IP_NAT_MANIP_SRC) | |
192 | var_ipp = &tuple->src.u3.ip; | |
193 | else | |
194 | var_ipp = &tuple->dst.u3.ip; | |
195 | ||
196 | /* Fast path: only one choice. */ | |
197 | if (range->min_ip == range->max_ip) { | |
198 | *var_ipp = range->min_ip; | |
199 | return; | |
200 | } | |
201 | ||
202 | /* Hashing source and destination IPs gives a fairly even | |
203 | * spread in practice (if there are a small number of IPs | |
204 | * involved, there usually aren't that many connections | |
205 | * anyway). The consistency means that servers see the same | |
206 | * client coming from the same IP (some Internet Banking sites | |
207 | * like this), even across reboots. */ | |
208 | minip = ntohl(range->min_ip); | |
209 | maxip = ntohl(range->max_ip); | |
210 | j = jhash_2words((__force u32)tuple->src.u3.ip, | |
98d500d6 | 211 | range->flags & IP_NAT_RANGE_PERSISTENT ? |
cce5a5c3 | 212 | 0 : (__force u32)tuple->dst.u3.ip, 0); |
34498825 PM |
213 | j = ((u64)j * (maxip - minip + 1)) >> 32; |
214 | *var_ipp = htonl(minip + j); | |
5b1158e9 JK |
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 | { | |
0c4c9288 | 230 | struct net *net = nf_ct_net(ct); |
2b628a08 | 231 | const struct nf_nat_protocol *proto; |
5b1158e9 JK |
232 | |
233 | /* 1) If this srcip/proto/src-proto-part is currently mapped, | |
234 | and that same mapping gives a unique tuple within the given | |
235 | range, use that. | |
236 | ||
237 | This is only required for source (ie. NAT/masq) mappings. | |
238 | So far, we don't do local source mappings, so multiple | |
239 | manips not an issue. */ | |
0dbff689 CG |
240 | if (maniptype == IP_NAT_MANIP_SRC && |
241 | !(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) { | |
0c4c9288 | 242 | if (find_appropriate_src(net, orig_tuple, tuple, range)) { |
0d53778e | 243 | pr_debug("get_unique_tuple: Found current src map\n"); |
0dbff689 CG |
244 | if (!nf_nat_used_tuple(tuple, ct)) |
245 | return; | |
5b1158e9 JK |
246 | } |
247 | } | |
248 | ||
249 | /* 2) Select the least-used IP/proto combination in the given | |
250 | range. */ | |
251 | *tuple = *orig_tuple; | |
252 | find_best_ips_proto(tuple, range, ct, maniptype); | |
253 | ||
254 | /* 3) The per-protocol part of the manip is made to map into | |
255 | the range to make a unique tuple. */ | |
256 | ||
e22a0548 PM |
257 | rcu_read_lock(); |
258 | proto = __nf_nat_proto_find(orig_tuple->dst.protonum); | |
5b1158e9 | 259 | |
41f4689a EL |
260 | /* Change protocol info to have some randomization */ |
261 | if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) { | |
262 | proto->unique_tuple(tuple, range, maniptype, ct); | |
e22a0548 | 263 | goto out; |
41f4689a EL |
264 | } |
265 | ||
5b1158e9 JK |
266 | /* Only bother mapping if it's not already in range and unique */ |
267 | if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) || | |
268 | proto->in_range(tuple, maniptype, &range->min, &range->max)) && | |
e22a0548 PM |
269 | !nf_nat_used_tuple(tuple, ct)) |
270 | goto out; | |
5b1158e9 JK |
271 | |
272 | /* Last change: get protocol to try to obtain unique tuple. */ | |
273 | proto->unique_tuple(tuple, range, maniptype, ct); | |
e22a0548 PM |
274 | out: |
275 | rcu_read_unlock(); | |
5b1158e9 JK |
276 | } |
277 | ||
278 | unsigned int | |
279 | nf_nat_setup_info(struct nf_conn *ct, | |
280 | const struct nf_nat_range *range, | |
cc01dcbd | 281 | enum nf_nat_manip_type maniptype) |
5b1158e9 | 282 | { |
0c4c9288 | 283 | struct net *net = nf_ct_net(ct); |
5b1158e9 | 284 | struct nf_conntrack_tuple curr_tuple, new_tuple; |
2d59e5ca | 285 | struct nf_conn_nat *nat; |
5b1158e9 | 286 | int have_to_hash = !(ct->status & IPS_NAT_DONE_MASK); |
5b1158e9 | 287 | |
2d59e5ca YK |
288 | /* nat helper or nfctnetlink also setup binding */ |
289 | nat = nfct_nat(ct); | |
290 | if (!nat) { | |
291 | nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC); | |
292 | if (nat == NULL) { | |
0d53778e | 293 | pr_debug("failed to add NAT extension\n"); |
2d59e5ca YK |
294 | return NF_ACCEPT; |
295 | } | |
296 | } | |
297 | ||
cc01dcbd PM |
298 | NF_CT_ASSERT(maniptype == IP_NAT_MANIP_SRC || |
299 | maniptype == IP_NAT_MANIP_DST); | |
5b1158e9 JK |
300 | BUG_ON(nf_nat_initialized(ct, maniptype)); |
301 | ||
302 | /* What we've got will look like inverse of reply. Normally | |
303 | this is what is in the conntrack, except for prior | |
304 | manipulations (future optimization: if num_manips == 0, | |
305 | orig_tp = | |
306 | conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */ | |
307 | nf_ct_invert_tuplepr(&curr_tuple, | |
308 | &ct->tuplehash[IP_CT_DIR_REPLY].tuple); | |
309 | ||
310 | get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype); | |
311 | ||
312 | if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) { | |
313 | struct nf_conntrack_tuple reply; | |
314 | ||
315 | /* Alter conntrack table so will recognize replies. */ | |
316 | nf_ct_invert_tuplepr(&reply, &new_tuple); | |
317 | nf_conntrack_alter_reply(ct, &reply); | |
318 | ||
319 | /* Non-atomic: we own this at the moment. */ | |
320 | if (maniptype == IP_NAT_MANIP_SRC) | |
321 | ct->status |= IPS_SRC_NAT; | |
322 | else | |
323 | ct->status |= IPS_DST_NAT; | |
324 | } | |
325 | ||
326 | /* Place in source hash if this is the first time. */ | |
327 | if (have_to_hash) { | |
328 | unsigned int srchash; | |
329 | ||
d696c7bd | 330 | srchash = hash_by_src(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); |
02502f62 | 331 | spin_lock_bh(&nf_nat_lock); |
2d59e5ca | 332 | /* nf_conntrack_alter_reply might re-allocate exntension aera */ |
b6b84d4a YK |
333 | nat = nfct_nat(ct); |
334 | nat->ct = ct; | |
0c4c9288 AD |
335 | hlist_add_head_rcu(&nat->bysource, |
336 | &net->ipv4.nat_bysource[srchash]); | |
02502f62 | 337 | spin_unlock_bh(&nf_nat_lock); |
5b1158e9 JK |
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. */ | |
f2ea825f | 351 | static bool |
5b1158e9 | 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))) |
f2ea825f | 362 | return false; |
5b1158e9 | 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)) |
f2ea825f | 371 | return false; |
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 | } | |
f2ea825f | 382 | return true; |
5b1158e9 JK |
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; | |
72b72949 | 428 | const 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 | ||
02502f62 | 523 | spin_lock_bh(&nf_nat_lock); |
5b1158e9 JK |
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 | 529 | out: |
02502f62 | 530 | spin_unlock_bh(&nf_nat_lock); |
5b1158e9 JK |
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 | 537 | { |
02502f62 | 538 | spin_lock_bh(&nf_nat_lock); |
e22a0548 PM |
539 | rcu_assign_pointer(nf_nat_protos[proto->protonum], |
540 | &nf_nat_unknown_protocol); | |
02502f62 | 541 | spin_unlock_bh(&nf_nat_lock); |
e22a0548 | 542 | synchronize_rcu(); |
5b1158e9 JK |
543 | } |
544 | EXPORT_SYMBOL(nf_nat_protocol_unregister); | |
545 | ||
d8a0509a YK |
546 | /* Noone using conntrack by the time this called. */ |
547 | static void nf_nat_cleanup_conntrack(struct nf_conn *ct) | |
548 | { | |
549 | struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT); | |
550 | ||
b6b84d4a | 551 | if (nat == NULL || nat->ct == NULL) |
d8a0509a YK |
552 | return; |
553 | ||
b6b84d4a | 554 | NF_CT_ASSERT(nat->ct->status & IPS_NAT_DONE_MASK); |
d8a0509a | 555 | |
02502f62 | 556 | spin_lock_bh(&nf_nat_lock); |
4d354c57 | 557 | hlist_del_rcu(&nat->bysource); |
02502f62 | 558 | spin_unlock_bh(&nf_nat_lock); |
d8a0509a YK |
559 | } |
560 | ||
86577c66 | 561 | static void nf_nat_move_storage(void *new, void *old) |
2d59e5ca | 562 | { |
86577c66 PM |
563 | struct nf_conn_nat *new_nat = new; |
564 | struct nf_conn_nat *old_nat = old; | |
b6b84d4a | 565 | struct nf_conn *ct = old_nat->ct; |
2d59e5ca | 566 | |
1f305323 | 567 | if (!ct || !(ct->status & IPS_NAT_DONE_MASK)) |
2d59e5ca YK |
568 | return; |
569 | ||
02502f62 | 570 | spin_lock_bh(&nf_nat_lock); |
b6b84d4a | 571 | new_nat->ct = ct; |
68b80f11 | 572 | hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource); |
02502f62 | 573 | spin_unlock_bh(&nf_nat_lock); |
2d59e5ca YK |
574 | } |
575 | ||
61eb3107 | 576 | static struct nf_ct_ext_type nat_extend __read_mostly = { |
d8a0509a YK |
577 | .len = sizeof(struct nf_conn_nat), |
578 | .align = __alignof__(struct nf_conn_nat), | |
579 | .destroy = nf_nat_cleanup_conntrack, | |
580 | .move = nf_nat_move_storage, | |
581 | .id = NF_CT_EXT_NAT, | |
582 | .flags = NF_CT_EXT_F_PREALLOC, | |
2d59e5ca YK |
583 | }; |
584 | ||
e6a7d3c0 PNA |
585 | #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
586 | ||
587 | #include <linux/netfilter/nfnetlink.h> | |
588 | #include <linux/netfilter/nfnetlink_conntrack.h> | |
589 | ||
590 | static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = { | |
591 | [CTA_PROTONAT_PORT_MIN] = { .type = NLA_U16 }, | |
592 | [CTA_PROTONAT_PORT_MAX] = { .type = NLA_U16 }, | |
593 | }; | |
594 | ||
595 | static int nfnetlink_parse_nat_proto(struct nlattr *attr, | |
596 | const struct nf_conn *ct, | |
597 | struct nf_nat_range *range) | |
598 | { | |
599 | struct nlattr *tb[CTA_PROTONAT_MAX+1]; | |
600 | const struct nf_nat_protocol *npt; | |
601 | int err; | |
602 | ||
603 | err = nla_parse_nested(tb, CTA_PROTONAT_MAX, attr, protonat_nla_policy); | |
604 | if (err < 0) | |
605 | return err; | |
606 | ||
607 | npt = nf_nat_proto_find_get(nf_ct_protonum(ct)); | |
608 | if (npt->nlattr_to_range) | |
609 | err = npt->nlattr_to_range(tb, range); | |
610 | nf_nat_proto_put(npt); | |
611 | return err; | |
612 | } | |
613 | ||
614 | static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = { | |
615 | [CTA_NAT_MINIP] = { .type = NLA_U32 }, | |
616 | [CTA_NAT_MAXIP] = { .type = NLA_U32 }, | |
617 | }; | |
618 | ||
619 | static int | |
39938324 | 620 | nfnetlink_parse_nat(const struct nlattr *nat, |
e6a7d3c0 PNA |
621 | const struct nf_conn *ct, struct nf_nat_range *range) |
622 | { | |
623 | struct nlattr *tb[CTA_NAT_MAX+1]; | |
624 | int err; | |
625 | ||
626 | memset(range, 0, sizeof(*range)); | |
627 | ||
628 | err = nla_parse_nested(tb, CTA_NAT_MAX, nat, nat_nla_policy); | |
629 | if (err < 0) | |
630 | return err; | |
631 | ||
632 | if (tb[CTA_NAT_MINIP]) | |
633 | range->min_ip = nla_get_be32(tb[CTA_NAT_MINIP]); | |
634 | ||
635 | if (!tb[CTA_NAT_MAXIP]) | |
636 | range->max_ip = range->min_ip; | |
637 | else | |
638 | range->max_ip = nla_get_be32(tb[CTA_NAT_MAXIP]); | |
639 | ||
640 | if (range->min_ip) | |
641 | range->flags |= IP_NAT_RANGE_MAP_IPS; | |
642 | ||
643 | if (!tb[CTA_NAT_PROTO]) | |
644 | return 0; | |
645 | ||
646 | err = nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range); | |
647 | if (err < 0) | |
648 | return err; | |
649 | ||
650 | return 0; | |
651 | } | |
652 | ||
653 | static int | |
654 | nfnetlink_parse_nat_setup(struct nf_conn *ct, | |
655 | enum nf_nat_manip_type manip, | |
39938324 | 656 | const struct nlattr *attr) |
e6a7d3c0 PNA |
657 | { |
658 | struct nf_nat_range range; | |
659 | ||
660 | if (nfnetlink_parse_nat(attr, ct, &range) < 0) | |
661 | return -EINVAL; | |
662 | if (nf_nat_initialized(ct, manip)) | |
663 | return -EEXIST; | |
664 | ||
665 | return nf_nat_setup_info(ct, &range, manip); | |
666 | } | |
667 | #else | |
668 | static int | |
669 | nfnetlink_parse_nat_setup(struct nf_conn *ct, | |
670 | enum nf_nat_manip_type manip, | |
39938324 | 671 | const struct nlattr *attr) |
e6a7d3c0 PNA |
672 | { |
673 | return -EOPNOTSUPP; | |
674 | } | |
675 | #endif | |
676 | ||
0c4c9288 AD |
677 | static int __net_init nf_nat_net_init(struct net *net) |
678 | { | |
d696c7bd PM |
679 | /* Leave them the same for the moment. */ |
680 | net->ipv4.nat_htable_size = net->ct.htable_size; | |
681 | net->ipv4.nat_bysource = nf_ct_alloc_hashtable(&net->ipv4.nat_htable_size, | |
682 | &net->ipv4.nat_vmalloced, 0); | |
0c4c9288 AD |
683 | if (!net->ipv4.nat_bysource) |
684 | return -ENOMEM; | |
685 | return 0; | |
686 | } | |
687 | ||
688 | /* Clear NAT section of all conntracks, in case we're loaded again. */ | |
689 | static int clean_nat(struct nf_conn *i, void *data) | |
690 | { | |
691 | struct nf_conn_nat *nat = nfct_nat(i); | |
692 | ||
693 | if (!nat) | |
694 | return 0; | |
695 | memset(nat, 0, sizeof(*nat)); | |
696 | i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST); | |
697 | return 0; | |
698 | } | |
699 | ||
700 | static void __net_exit nf_nat_net_exit(struct net *net) | |
701 | { | |
702 | nf_ct_iterate_cleanup(net, &clean_nat, NULL); | |
703 | synchronize_rcu(); | |
704 | nf_ct_free_hashtable(net->ipv4.nat_bysource, net->ipv4.nat_vmalloced, | |
d696c7bd | 705 | net->ipv4.nat_htable_size); |
0c4c9288 AD |
706 | } |
707 | ||
708 | static struct pernet_operations nf_nat_net_ops = { | |
709 | .init = nf_nat_net_init, | |
710 | .exit = nf_nat_net_exit, | |
711 | }; | |
712 | ||
5b1158e9 JK |
713 | static int __init nf_nat_init(void) |
714 | { | |
715 | size_t i; | |
2d59e5ca YK |
716 | int ret; |
717 | ||
475959d4 JE |
718 | need_ipv4_conntrack(); |
719 | ||
2d59e5ca YK |
720 | ret = nf_ct_extend_register(&nat_extend); |
721 | if (ret < 0) { | |
722 | printk(KERN_ERR "nf_nat_core: Unable to register extension\n"); | |
723 | return ret; | |
724 | } | |
5b1158e9 | 725 | |
0c4c9288 AD |
726 | ret = register_pernet_subsys(&nf_nat_net_ops); |
727 | if (ret < 0) | |
2d59e5ca | 728 | goto cleanup_extend; |
5b1158e9 JK |
729 | |
730 | /* Sew in builtin protocols. */ | |
02502f62 | 731 | spin_lock_bh(&nf_nat_lock); |
5b1158e9 | 732 | for (i = 0; i < MAX_IP_NAT_PROTO; i++) |
e22a0548 PM |
733 | rcu_assign_pointer(nf_nat_protos[i], &nf_nat_unknown_protocol); |
734 | rcu_assign_pointer(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp); | |
735 | rcu_assign_pointer(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp); | |
736 | rcu_assign_pointer(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp); | |
02502f62 | 737 | spin_unlock_bh(&nf_nat_lock); |
5b1158e9 | 738 | |
5b1158e9 JK |
739 | /* Initialize fake conntrack so that NAT will skip it */ |
740 | nf_conntrack_untracked.status |= IPS_NAT_DONE_MASK; | |
741 | ||
742 | l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET); | |
dd13b010 PM |
743 | |
744 | BUG_ON(nf_nat_seq_adjust_hook != NULL); | |
745 | rcu_assign_pointer(nf_nat_seq_adjust_hook, nf_nat_seq_adjust); | |
e6a7d3c0 PNA |
746 | BUG_ON(nfnetlink_parse_nat_setup_hook != NULL); |
747 | rcu_assign_pointer(nfnetlink_parse_nat_setup_hook, | |
748 | nfnetlink_parse_nat_setup); | |
f9dd09c7 JK |
749 | BUG_ON(nf_ct_nat_offset != NULL); |
750 | rcu_assign_pointer(nf_ct_nat_offset, nf_nat_get_offset); | |
5b1158e9 | 751 | return 0; |
2d59e5ca YK |
752 | |
753 | cleanup_extend: | |
754 | nf_ct_extend_unregister(&nat_extend); | |
755 | return ret; | |
5b1158e9 JK |
756 | } |
757 | ||
5b1158e9 JK |
758 | static void __exit nf_nat_cleanup(void) |
759 | { | |
0c4c9288 | 760 | unregister_pernet_subsys(&nf_nat_net_ops); |
5b1158e9 | 761 | nf_ct_l3proto_put(l3proto); |
2d59e5ca | 762 | nf_ct_extend_unregister(&nat_extend); |
dd13b010 | 763 | rcu_assign_pointer(nf_nat_seq_adjust_hook, NULL); |
e6a7d3c0 | 764 | rcu_assign_pointer(nfnetlink_parse_nat_setup_hook, NULL); |
f9dd09c7 | 765 | rcu_assign_pointer(nf_ct_nat_offset, NULL); |
dd13b010 | 766 | synchronize_net(); |
5b1158e9 JK |
767 | } |
768 | ||
769 | MODULE_LICENSE("GPL"); | |
e6a7d3c0 | 770 | MODULE_ALIAS("nf-nat-ipv4"); |
5b1158e9 JK |
771 | |
772 | module_init(nf_nat_init); | |
773 | module_exit(nf_nat_cleanup); |