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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> | |
5a0e3ad6 | 15 | #include <linux/gfp.h> |
5b1158e9 JK |
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> | |
5d0aa2cc | 33 | #include <net/netfilter/nf_conntrack_zones.h> |
5b1158e9 | 34 | |
02502f62 | 35 | static DEFINE_SPINLOCK(nf_nat_lock); |
5b1158e9 | 36 | |
ce4b1ceb | 37 | static struct nf_conntrack_l3proto *l3proto __read_mostly; |
5b1158e9 | 38 | |
5b1158e9 | 39 | #define MAX_IP_NAT_PROTO 256 |
0906a372 | 40 | static const struct nf_nat_protocol __rcu *nf_nat_protos[MAX_IP_NAT_PROTO] |
ce4b1ceb | 41 | __read_mostly; |
5b1158e9 | 42 | |
2b628a08 | 43 | static inline const struct nf_nat_protocol * |
5b1158e9 JK |
44 | __nf_nat_proto_find(u_int8_t protonum) |
45 | { | |
e22a0548 | 46 | return rcu_dereference(nf_nat_protos[protonum]); |
5b1158e9 JK |
47 | } |
48 | ||
5b1158e9 JK |
49 | /* We keep an extra hash for each conntrack, for fast searching. */ |
50 | static inline unsigned int | |
5d0aa2cc PM |
51 | hash_by_src(const struct net *net, u16 zone, |
52 | const struct nf_conntrack_tuple *tuple) | |
5b1158e9 | 53 | { |
34498825 PM |
54 | unsigned int hash; |
55 | ||
5b1158e9 | 56 | /* Original src, to ensure we map it consistently if poss. */ |
34498825 | 57 | hash = jhash_3words((__force u32)tuple->src.u3.ip, |
5d0aa2cc | 58 | (__force u32)tuple->src.u.all ^ zone, |
4d4e61c6 | 59 | tuple->dst.protonum, nf_conntrack_hash_rnd); |
d696c7bd | 60 | return ((u64)hash * net->ipv4.nat_htable_size) >> 32; |
5b1158e9 JK |
61 | } |
62 | ||
5b1158e9 JK |
63 | /* Is this tuple already taken? (not by us) */ |
64 | int | |
65 | nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple, | |
66 | const struct nf_conn *ignored_conntrack) | |
67 | { | |
68 | /* Conntrack tracking doesn't keep track of outgoing tuples; only | |
69 | incoming ones. NAT means they don't have a fixed mapping, | |
70 | so we invert the tuple and look for the incoming reply. | |
71 | ||
72 | We could keep a separate hash if this proves too slow. */ | |
73 | struct nf_conntrack_tuple reply; | |
74 | ||
75 | nf_ct_invert_tuplepr(&reply, tuple); | |
76 | return nf_conntrack_tuple_taken(&reply, ignored_conntrack); | |
77 | } | |
78 | EXPORT_SYMBOL(nf_nat_used_tuple); | |
79 | ||
80 | /* If we source map this tuple so reply looks like reply_tuple, will | |
81 | * that meet the constraints of range. */ | |
82 | static int | |
83 | in_range(const struct nf_conntrack_tuple *tuple, | |
cbc9f2f4 | 84 | const struct nf_nat_ipv4_range *range) |
5b1158e9 | 85 | { |
2b628a08 | 86 | const struct nf_nat_protocol *proto; |
e22a0548 | 87 | int ret = 0; |
5b1158e9 | 88 | |
5b1158e9 JK |
89 | /* If we are supposed to map IPs, then we must be in the |
90 | range specified, otherwise let this drag us onto a new src IP. */ | |
cbc9f2f4 | 91 | if (range->flags & NF_NAT_RANGE_MAP_IPS) { |
5b1158e9 JK |
92 | if (ntohl(tuple->src.u3.ip) < ntohl(range->min_ip) || |
93 | ntohl(tuple->src.u3.ip) > ntohl(range->max_ip)) | |
94 | return 0; | |
95 | } | |
96 | ||
e22a0548 PM |
97 | rcu_read_lock(); |
98 | proto = __nf_nat_proto_find(tuple->dst.protonum); | |
cbc9f2f4 PM |
99 | if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) || |
100 | proto->in_range(tuple, NF_NAT_MANIP_SRC, | |
5b1158e9 | 101 | &range->min, &range->max)) |
e22a0548 PM |
102 | ret = 1; |
103 | rcu_read_unlock(); | |
5b1158e9 | 104 | |
e22a0548 | 105 | return ret; |
5b1158e9 JK |
106 | } |
107 | ||
108 | static inline int | |
109 | same_src(const struct nf_conn *ct, | |
110 | const struct nf_conntrack_tuple *tuple) | |
111 | { | |
112 | const struct nf_conntrack_tuple *t; | |
113 | ||
114 | t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; | |
115 | return (t->dst.protonum == tuple->dst.protonum && | |
116 | t->src.u3.ip == tuple->src.u3.ip && | |
117 | t->src.u.all == tuple->src.u.all); | |
118 | } | |
119 | ||
120 | /* Only called for SRC manip */ | |
121 | static int | |
5d0aa2cc | 122 | find_appropriate_src(struct net *net, u16 zone, |
0c4c9288 | 123 | const struct nf_conntrack_tuple *tuple, |
5b1158e9 | 124 | struct nf_conntrack_tuple *result, |
cbc9f2f4 | 125 | const struct nf_nat_ipv4_range *range) |
5b1158e9 | 126 | { |
5d0aa2cc | 127 | unsigned int h = hash_by_src(net, zone, tuple); |
72b72949 JE |
128 | const struct nf_conn_nat *nat; |
129 | const struct nf_conn *ct; | |
130 | const struct hlist_node *n; | |
5b1158e9 | 131 | |
4d354c57 | 132 | rcu_read_lock(); |
0c4c9288 | 133 | hlist_for_each_entry_rcu(nat, n, &net->ipv4.nat_bysource[h], bysource) { |
b6b84d4a | 134 | ct = nat->ct; |
5d0aa2cc | 135 | if (same_src(ct, tuple) && nf_ct_zone(ct) == zone) { |
5b1158e9 JK |
136 | /* Copy source part from reply tuple. */ |
137 | nf_ct_invert_tuplepr(result, | |
138 | &ct->tuplehash[IP_CT_DIR_REPLY].tuple); | |
139 | result->dst = tuple->dst; | |
140 | ||
141 | if (in_range(result, range)) { | |
4d354c57 | 142 | rcu_read_unlock(); |
5b1158e9 JK |
143 | return 1; |
144 | } | |
145 | } | |
146 | } | |
4d354c57 | 147 | rcu_read_unlock(); |
5b1158e9 JK |
148 | return 0; |
149 | } | |
150 | ||
151 | /* For [FUTURE] fragmentation handling, we want the least-used | |
152 | src-ip/dst-ip/proto triple. Fairness doesn't come into it. Thus | |
153 | if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports | |
154 | 1-65535, we don't do pro-rata allocation based on ports; we choose | |
155 | the ip with the lowest src-ip/dst-ip/proto usage. | |
156 | */ | |
157 | static void | |
5d0aa2cc | 158 | find_best_ips_proto(u16 zone, struct nf_conntrack_tuple *tuple, |
cbc9f2f4 | 159 | const struct nf_nat_ipv4_range *range, |
5b1158e9 JK |
160 | const struct nf_conn *ct, |
161 | enum nf_nat_manip_type maniptype) | |
162 | { | |
163 | __be32 *var_ipp; | |
164 | /* Host order */ | |
165 | u_int32_t minip, maxip, j; | |
166 | ||
167 | /* No IP mapping? Do nothing. */ | |
cbc9f2f4 | 168 | if (!(range->flags & NF_NAT_RANGE_MAP_IPS)) |
5b1158e9 JK |
169 | return; |
170 | ||
cbc9f2f4 | 171 | if (maniptype == NF_NAT_MANIP_SRC) |
5b1158e9 JK |
172 | var_ipp = &tuple->src.u3.ip; |
173 | else | |
174 | var_ipp = &tuple->dst.u3.ip; | |
175 | ||
176 | /* Fast path: only one choice. */ | |
177 | if (range->min_ip == range->max_ip) { | |
178 | *var_ipp = range->min_ip; | |
179 | return; | |
180 | } | |
181 | ||
182 | /* Hashing source and destination IPs gives a fairly even | |
183 | * spread in practice (if there are a small number of IPs | |
184 | * involved, there usually aren't that many connections | |
185 | * anyway). The consistency means that servers see the same | |
186 | * client coming from the same IP (some Internet Banking sites | |
187 | * like this), even across reboots. */ | |
188 | minip = ntohl(range->min_ip); | |
189 | maxip = ntohl(range->max_ip); | |
190 | j = jhash_2words((__force u32)tuple->src.u3.ip, | |
cbc9f2f4 | 191 | range->flags & NF_NAT_RANGE_PERSISTENT ? |
5d0aa2cc | 192 | 0 : (__force u32)tuple->dst.u3.ip ^ zone, 0); |
34498825 PM |
193 | j = ((u64)j * (maxip - minip + 1)) >> 32; |
194 | *var_ipp = htonl(minip + j); | |
5b1158e9 JK |
195 | } |
196 | ||
6e23ae2a PM |
197 | /* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING, |
198 | * we change the source to map into the range. For NF_INET_PRE_ROUTING | |
199 | * and NF_INET_LOCAL_OUT, we change the destination to map into the | |
5b1158e9 JK |
200 | * range. It might not be possible to get a unique tuple, but we try. |
201 | * At worst (or if we race), we will end up with a final duplicate in | |
202 | * __ip_conntrack_confirm and drop the packet. */ | |
203 | static void | |
204 | get_unique_tuple(struct nf_conntrack_tuple *tuple, | |
205 | const struct nf_conntrack_tuple *orig_tuple, | |
cbc9f2f4 | 206 | const struct nf_nat_ipv4_range *range, |
5b1158e9 JK |
207 | struct nf_conn *ct, |
208 | enum nf_nat_manip_type maniptype) | |
209 | { | |
0c4c9288 | 210 | struct net *net = nf_ct_net(ct); |
2b628a08 | 211 | const struct nf_nat_protocol *proto; |
5d0aa2cc | 212 | u16 zone = nf_ct_zone(ct); |
5b1158e9 JK |
213 | |
214 | /* 1) If this srcip/proto/src-proto-part is currently mapped, | |
215 | and that same mapping gives a unique tuple within the given | |
216 | range, use that. | |
217 | ||
218 | This is only required for source (ie. NAT/masq) mappings. | |
219 | So far, we don't do local source mappings, so multiple | |
220 | manips not an issue. */ | |
cbc9f2f4 PM |
221 | if (maniptype == NF_NAT_MANIP_SRC && |
222 | !(range->flags & NF_NAT_RANGE_PROTO_RANDOM)) { | |
41a7cab6 CG |
223 | /* try the original tuple first */ |
224 | if (in_range(orig_tuple, range)) { | |
225 | if (!nf_nat_used_tuple(orig_tuple, ct)) { | |
226 | *tuple = *orig_tuple; | |
227 | return; | |
228 | } | |
229 | } else if (find_appropriate_src(net, zone, orig_tuple, tuple, | |
230 | range)) { | |
0d53778e | 231 | pr_debug("get_unique_tuple: Found current src map\n"); |
0dbff689 CG |
232 | if (!nf_nat_used_tuple(tuple, ct)) |
233 | return; | |
5b1158e9 JK |
234 | } |
235 | } | |
236 | ||
237 | /* 2) Select the least-used IP/proto combination in the given | |
238 | range. */ | |
239 | *tuple = *orig_tuple; | |
5d0aa2cc | 240 | find_best_ips_proto(zone, tuple, range, ct, maniptype); |
5b1158e9 JK |
241 | |
242 | /* 3) The per-protocol part of the manip is made to map into | |
243 | the range to make a unique tuple. */ | |
244 | ||
e22a0548 PM |
245 | rcu_read_lock(); |
246 | proto = __nf_nat_proto_find(orig_tuple->dst.protonum); | |
5b1158e9 JK |
247 | |
248 | /* Only bother mapping if it's not already in range and unique */ | |
cbc9f2f4 PM |
249 | if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM)) { |
250 | if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) { | |
99ad3c53 CG |
251 | if (proto->in_range(tuple, maniptype, &range->min, |
252 | &range->max) && | |
253 | (range->min.all == range->max.all || | |
254 | !nf_nat_used_tuple(tuple, ct))) | |
255 | goto out; | |
256 | } else if (!nf_nat_used_tuple(tuple, ct)) { | |
257 | goto out; | |
258 | } | |
259 | } | |
5b1158e9 JK |
260 | |
261 | /* Last change: get protocol to try to obtain unique tuple. */ | |
262 | proto->unique_tuple(tuple, range, maniptype, ct); | |
e22a0548 PM |
263 | out: |
264 | rcu_read_unlock(); | |
5b1158e9 JK |
265 | } |
266 | ||
267 | unsigned int | |
268 | nf_nat_setup_info(struct nf_conn *ct, | |
cbc9f2f4 | 269 | const struct nf_nat_ipv4_range *range, |
cc01dcbd | 270 | enum nf_nat_manip_type maniptype) |
5b1158e9 | 271 | { |
0c4c9288 | 272 | struct net *net = nf_ct_net(ct); |
5b1158e9 | 273 | struct nf_conntrack_tuple curr_tuple, new_tuple; |
2d59e5ca | 274 | struct nf_conn_nat *nat; |
5b1158e9 | 275 | |
2d59e5ca YK |
276 | /* nat helper or nfctnetlink also setup binding */ |
277 | nat = nfct_nat(ct); | |
278 | if (!nat) { | |
279 | nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC); | |
280 | if (nat == NULL) { | |
0d53778e | 281 | pr_debug("failed to add NAT extension\n"); |
2d59e5ca YK |
282 | return NF_ACCEPT; |
283 | } | |
284 | } | |
285 | ||
cbc9f2f4 PM |
286 | NF_CT_ASSERT(maniptype == NF_NAT_MANIP_SRC || |
287 | maniptype == NF_NAT_MANIP_DST); | |
5b1158e9 JK |
288 | BUG_ON(nf_nat_initialized(ct, maniptype)); |
289 | ||
290 | /* What we've got will look like inverse of reply. Normally | |
291 | this is what is in the conntrack, except for prior | |
292 | manipulations (future optimization: if num_manips == 0, | |
293 | orig_tp = | |
294 | conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */ | |
295 | nf_ct_invert_tuplepr(&curr_tuple, | |
296 | &ct->tuplehash[IP_CT_DIR_REPLY].tuple); | |
297 | ||
298 | get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype); | |
299 | ||
300 | if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) { | |
301 | struct nf_conntrack_tuple reply; | |
302 | ||
303 | /* Alter conntrack table so will recognize replies. */ | |
304 | nf_ct_invert_tuplepr(&reply, &new_tuple); | |
305 | nf_conntrack_alter_reply(ct, &reply); | |
306 | ||
307 | /* Non-atomic: we own this at the moment. */ | |
cbc9f2f4 | 308 | if (maniptype == NF_NAT_MANIP_SRC) |
5b1158e9 JK |
309 | ct->status |= IPS_SRC_NAT; |
310 | else | |
311 | ct->status |= IPS_DST_NAT; | |
312 | } | |
313 | ||
cbc9f2f4 | 314 | if (maniptype == NF_NAT_MANIP_SRC) { |
5b1158e9 JK |
315 | unsigned int srchash; |
316 | ||
5d0aa2cc PM |
317 | srchash = hash_by_src(net, nf_ct_zone(ct), |
318 | &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); | |
02502f62 | 319 | spin_lock_bh(&nf_nat_lock); |
819a693b | 320 | /* nf_conntrack_alter_reply might re-allocate extension area */ |
b6b84d4a YK |
321 | nat = nfct_nat(ct); |
322 | nat->ct = ct; | |
0c4c9288 AD |
323 | hlist_add_head_rcu(&nat->bysource, |
324 | &net->ipv4.nat_bysource[srchash]); | |
02502f62 | 325 | spin_unlock_bh(&nf_nat_lock); |
5b1158e9 JK |
326 | } |
327 | ||
328 | /* It's done. */ | |
cbc9f2f4 | 329 | if (maniptype == NF_NAT_MANIP_DST) |
a7c2f4d7 | 330 | ct->status |= IPS_DST_NAT_DONE; |
5b1158e9 | 331 | else |
a7c2f4d7 | 332 | ct->status |= IPS_SRC_NAT_DONE; |
5b1158e9 JK |
333 | |
334 | return NF_ACCEPT; | |
335 | } | |
336 | EXPORT_SYMBOL(nf_nat_setup_info); | |
337 | ||
338 | /* Returns true if succeeded. */ | |
f2ea825f | 339 | static bool |
5b1158e9 | 340 | manip_pkt(u_int16_t proto, |
3db05fea | 341 | struct sk_buff *skb, |
5b1158e9 JK |
342 | unsigned int iphdroff, |
343 | const struct nf_conntrack_tuple *target, | |
344 | enum nf_nat_manip_type maniptype) | |
345 | { | |
346 | struct iphdr *iph; | |
2b628a08 | 347 | const struct nf_nat_protocol *p; |
5b1158e9 | 348 | |
3db05fea | 349 | if (!skb_make_writable(skb, iphdroff + sizeof(*iph))) |
f2ea825f | 350 | return false; |
5b1158e9 | 351 | |
3db05fea | 352 | iph = (void *)skb->data + iphdroff; |
5b1158e9 JK |
353 | |
354 | /* Manipulate protcol part. */ | |
e22a0548 PM |
355 | |
356 | /* rcu_read_lock()ed by nf_hook_slow */ | |
357 | p = __nf_nat_proto_find(proto); | |
3db05fea | 358 | if (!p->manip_pkt(skb, iphdroff, target, maniptype)) |
f2ea825f | 359 | return false; |
5b1158e9 | 360 | |
3db05fea | 361 | iph = (void *)skb->data + iphdroff; |
5b1158e9 | 362 | |
cbc9f2f4 | 363 | if (maniptype == NF_NAT_MANIP_SRC) { |
be0ea7d5 | 364 | csum_replace4(&iph->check, iph->saddr, target->src.u3.ip); |
5b1158e9 JK |
365 | iph->saddr = target->src.u3.ip; |
366 | } else { | |
be0ea7d5 | 367 | csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip); |
5b1158e9 JK |
368 | iph->daddr = target->dst.u3.ip; |
369 | } | |
f2ea825f | 370 | return true; |
5b1158e9 JK |
371 | } |
372 | ||
373 | /* Do packet manipulations according to nf_nat_setup_info. */ | |
374 | unsigned int nf_nat_packet(struct nf_conn *ct, | |
375 | enum ip_conntrack_info ctinfo, | |
376 | unsigned int hooknum, | |
3db05fea | 377 | struct sk_buff *skb) |
5b1158e9 JK |
378 | { |
379 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); | |
380 | unsigned long statusbit; | |
381 | enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum); | |
382 | ||
cbc9f2f4 | 383 | if (mtype == NF_NAT_MANIP_SRC) |
5b1158e9 JK |
384 | statusbit = IPS_SRC_NAT; |
385 | else | |
386 | statusbit = IPS_DST_NAT; | |
387 | ||
388 | /* Invert if this is reply dir. */ | |
389 | if (dir == IP_CT_DIR_REPLY) | |
390 | statusbit ^= IPS_NAT_MASK; | |
391 | ||
392 | /* Non-atomic: these bits don't change. */ | |
393 | if (ct->status & statusbit) { | |
394 | struct nf_conntrack_tuple target; | |
395 | ||
396 | /* We are aiming to look like inverse of other direction. */ | |
397 | nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple); | |
398 | ||
3db05fea | 399 | if (!manip_pkt(target.dst.protonum, skb, 0, &target, mtype)) |
5b1158e9 JK |
400 | return NF_DROP; |
401 | } | |
402 | return NF_ACCEPT; | |
403 | } | |
404 | EXPORT_SYMBOL_GPL(nf_nat_packet); | |
405 | ||
406 | /* Dir is direction ICMP is coming from (opposite to packet it contains) */ | |
407 | int nf_nat_icmp_reply_translation(struct nf_conn *ct, | |
408 | enum ip_conntrack_info ctinfo, | |
409 | unsigned int hooknum, | |
3db05fea | 410 | struct sk_buff *skb) |
5b1158e9 JK |
411 | { |
412 | struct { | |
413 | struct icmphdr icmp; | |
414 | struct iphdr ip; | |
415 | } *inside; | |
40cfb706 | 416 | struct nf_conntrack_tuple target; |
3db05fea | 417 | int hdrlen = ip_hdrlen(skb); |
5b1158e9 JK |
418 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
419 | unsigned long statusbit; | |
420 | enum nf_nat_manip_type manip = HOOK2MANIP(hooknum); | |
421 | ||
3db05fea | 422 | if (!skb_make_writable(skb, hdrlen + sizeof(*inside))) |
5b1158e9 JK |
423 | return 0; |
424 | ||
794dbc1d | 425 | inside = (void *)skb->data + hdrlen; |
5b1158e9 JK |
426 | |
427 | /* We're actually going to mangle it beyond trivial checksum | |
428 | adjustment, so make sure the current checksum is correct. */ | |
3db05fea | 429 | if (nf_ip_checksum(skb, hooknum, hdrlen, 0)) |
5b1158e9 JK |
430 | return 0; |
431 | ||
432 | /* Must be RELATED */ | |
3db05fea | 433 | NF_CT_ASSERT(skb->nfctinfo == IP_CT_RELATED || |
fb048833 | 434 | skb->nfctinfo == IP_CT_RELATED_REPLY); |
5b1158e9 JK |
435 | |
436 | /* Redirects on non-null nats must be dropped, else they'll | |
e905a9ed YH |
437 | start talking to each other without our translation, and be |
438 | confused... --RR */ | |
5b1158e9 JK |
439 | if (inside->icmp.type == ICMP_REDIRECT) { |
440 | /* If NAT isn't finished, assume it and drop. */ | |
441 | if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK) | |
442 | return 0; | |
443 | ||
444 | if (ct->status & IPS_NAT_MASK) | |
445 | return 0; | |
446 | } | |
447 | ||
cbc9f2f4 | 448 | if (manip == NF_NAT_MANIP_SRC) |
b0aeef30 JA |
449 | statusbit = IPS_SRC_NAT; |
450 | else | |
451 | statusbit = IPS_DST_NAT; | |
452 | ||
453 | /* Invert if this is reply dir. */ | |
454 | if (dir == IP_CT_DIR_REPLY) | |
455 | statusbit ^= IPS_NAT_MASK; | |
456 | ||
457 | if (!(ct->status & statusbit)) | |
458 | return 1; | |
459 | ||
0d53778e | 460 | pr_debug("icmp_reply_translation: translating error %p manip %u " |
3db05fea | 461 | "dir %s\n", skb, manip, |
0d53778e | 462 | dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY"); |
5b1158e9 | 463 | |
5b1158e9 JK |
464 | /* Change inner back to look like incoming packet. We do the |
465 | opposite manip on this hook to normal, because it might not | |
466 | pass all hooks (locally-generated ICMP). Consider incoming | |
467 | packet: PREROUTING (DST manip), routing produces ICMP, goes | |
468 | through POSTROUTING (which must correct the DST manip). */ | |
794dbc1d CG |
469 | if (!manip_pkt(inside->ip.protocol, skb, hdrlen + sizeof(inside->icmp), |
470 | &ct->tuplehash[!dir].tuple, !manip)) | |
5b1158e9 JK |
471 | return 0; |
472 | ||
3db05fea | 473 | if (skb->ip_summed != CHECKSUM_PARTIAL) { |
5b1158e9 | 474 | /* Reloading "inside" here since manip_pkt inner. */ |
794dbc1d | 475 | inside = (void *)skb->data + hdrlen; |
5b1158e9 JK |
476 | inside->icmp.checksum = 0; |
477 | inside->icmp.checksum = | |
3db05fea HX |
478 | csum_fold(skb_checksum(skb, hdrlen, |
479 | skb->len - hdrlen, 0)); | |
5b1158e9 JK |
480 | } |
481 | ||
482 | /* Change outer to look the reply to an incoming packet | |
483 | * (proto 0 means don't invert per-proto part). */ | |
b0aeef30 JA |
484 | nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple); |
485 | if (!manip_pkt(0, skb, 0, &target, manip)) | |
486 | return 0; | |
5b1158e9 JK |
487 | |
488 | return 1; | |
489 | } | |
490 | EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation); | |
491 | ||
492 | /* Protocol registration. */ | |
2b628a08 | 493 | int nf_nat_protocol_register(const struct nf_nat_protocol *proto) |
5b1158e9 JK |
494 | { |
495 | int ret = 0; | |
496 | ||
02502f62 | 497 | spin_lock_bh(&nf_nat_lock); |
eb733162 ED |
498 | if (rcu_dereference_protected( |
499 | nf_nat_protos[proto->protonum], | |
500 | lockdep_is_held(&nf_nat_lock) | |
501 | ) != &nf_nat_unknown_protocol) { | |
5b1158e9 JK |
502 | ret = -EBUSY; |
503 | goto out; | |
504 | } | |
a9b3cd7f | 505 | RCU_INIT_POINTER(nf_nat_protos[proto->protonum], proto); |
5b1158e9 | 506 | out: |
02502f62 | 507 | spin_unlock_bh(&nf_nat_lock); |
5b1158e9 JK |
508 | return ret; |
509 | } | |
510 | EXPORT_SYMBOL(nf_nat_protocol_register); | |
511 | ||
25985edc | 512 | /* No one stores the protocol anywhere; simply delete it. */ |
2b628a08 | 513 | void nf_nat_protocol_unregister(const struct nf_nat_protocol *proto) |
5b1158e9 | 514 | { |
02502f62 | 515 | spin_lock_bh(&nf_nat_lock); |
a9b3cd7f | 516 | RCU_INIT_POINTER(nf_nat_protos[proto->protonum], |
e22a0548 | 517 | &nf_nat_unknown_protocol); |
02502f62 | 518 | spin_unlock_bh(&nf_nat_lock); |
e22a0548 | 519 | synchronize_rcu(); |
5b1158e9 JK |
520 | } |
521 | EXPORT_SYMBOL(nf_nat_protocol_unregister); | |
522 | ||
25985edc | 523 | /* No one using conntrack by the time this called. */ |
d8a0509a YK |
524 | static void nf_nat_cleanup_conntrack(struct nf_conn *ct) |
525 | { | |
526 | struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT); | |
527 | ||
b6b84d4a | 528 | if (nat == NULL || nat->ct == NULL) |
d8a0509a YK |
529 | return; |
530 | ||
41a7cab6 | 531 | NF_CT_ASSERT(nat->ct->status & IPS_SRC_NAT_DONE); |
d8a0509a | 532 | |
02502f62 | 533 | spin_lock_bh(&nf_nat_lock); |
4d354c57 | 534 | hlist_del_rcu(&nat->bysource); |
02502f62 | 535 | spin_unlock_bh(&nf_nat_lock); |
d8a0509a YK |
536 | } |
537 | ||
86577c66 | 538 | static void nf_nat_move_storage(void *new, void *old) |
2d59e5ca | 539 | { |
86577c66 PM |
540 | struct nf_conn_nat *new_nat = new; |
541 | struct nf_conn_nat *old_nat = old; | |
b6b84d4a | 542 | struct nf_conn *ct = old_nat->ct; |
2d59e5ca | 543 | |
41a7cab6 | 544 | if (!ct || !(ct->status & IPS_SRC_NAT_DONE)) |
2d59e5ca YK |
545 | return; |
546 | ||
02502f62 | 547 | spin_lock_bh(&nf_nat_lock); |
68b80f11 | 548 | hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource); |
02502f62 | 549 | spin_unlock_bh(&nf_nat_lock); |
2d59e5ca YK |
550 | } |
551 | ||
61eb3107 | 552 | static struct nf_ct_ext_type nat_extend __read_mostly = { |
d8a0509a YK |
553 | .len = sizeof(struct nf_conn_nat), |
554 | .align = __alignof__(struct nf_conn_nat), | |
555 | .destroy = nf_nat_cleanup_conntrack, | |
556 | .move = nf_nat_move_storage, | |
557 | .id = NF_CT_EXT_NAT, | |
558 | .flags = NF_CT_EXT_F_PREALLOC, | |
2d59e5ca YK |
559 | }; |
560 | ||
e6a7d3c0 PNA |
561 | #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
562 | ||
563 | #include <linux/netfilter/nfnetlink.h> | |
564 | #include <linux/netfilter/nfnetlink_conntrack.h> | |
565 | ||
566 | static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = { | |
567 | [CTA_PROTONAT_PORT_MIN] = { .type = NLA_U16 }, | |
568 | [CTA_PROTONAT_PORT_MAX] = { .type = NLA_U16 }, | |
569 | }; | |
570 | ||
571 | static int nfnetlink_parse_nat_proto(struct nlattr *attr, | |
572 | const struct nf_conn *ct, | |
cbc9f2f4 | 573 | struct nf_nat_ipv4_range *range) |
e6a7d3c0 PNA |
574 | { |
575 | struct nlattr *tb[CTA_PROTONAT_MAX+1]; | |
576 | const struct nf_nat_protocol *npt; | |
577 | int err; | |
578 | ||
579 | err = nla_parse_nested(tb, CTA_PROTONAT_MAX, attr, protonat_nla_policy); | |
580 | if (err < 0) | |
581 | return err; | |
582 | ||
d70308f7 PM |
583 | rcu_read_lock(); |
584 | npt = __nf_nat_proto_find(nf_ct_protonum(ct)); | |
e6a7d3c0 PNA |
585 | if (npt->nlattr_to_range) |
586 | err = npt->nlattr_to_range(tb, range); | |
d70308f7 | 587 | rcu_read_unlock(); |
e6a7d3c0 PNA |
588 | return err; |
589 | } | |
590 | ||
591 | static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = { | |
592 | [CTA_NAT_MINIP] = { .type = NLA_U32 }, | |
593 | [CTA_NAT_MAXIP] = { .type = NLA_U32 }, | |
329fb58a | 594 | [CTA_NAT_PROTO] = { .type = NLA_NESTED }, |
e6a7d3c0 PNA |
595 | }; |
596 | ||
597 | static int | |
39938324 | 598 | nfnetlink_parse_nat(const struct nlattr *nat, |
cbc9f2f4 | 599 | const struct nf_conn *ct, struct nf_nat_ipv4_range *range) |
e6a7d3c0 PNA |
600 | { |
601 | struct nlattr *tb[CTA_NAT_MAX+1]; | |
602 | int err; | |
603 | ||
604 | memset(range, 0, sizeof(*range)); | |
605 | ||
606 | err = nla_parse_nested(tb, CTA_NAT_MAX, nat, nat_nla_policy); | |
607 | if (err < 0) | |
608 | return err; | |
609 | ||
610 | if (tb[CTA_NAT_MINIP]) | |
611 | range->min_ip = nla_get_be32(tb[CTA_NAT_MINIP]); | |
612 | ||
613 | if (!tb[CTA_NAT_MAXIP]) | |
614 | range->max_ip = range->min_ip; | |
615 | else | |
616 | range->max_ip = nla_get_be32(tb[CTA_NAT_MAXIP]); | |
617 | ||
618 | if (range->min_ip) | |
cbc9f2f4 | 619 | range->flags |= NF_NAT_RANGE_MAP_IPS; |
e6a7d3c0 PNA |
620 | |
621 | if (!tb[CTA_NAT_PROTO]) | |
622 | return 0; | |
623 | ||
624 | err = nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range); | |
625 | if (err < 0) | |
626 | return err; | |
627 | ||
628 | return 0; | |
629 | } | |
630 | ||
631 | static int | |
632 | nfnetlink_parse_nat_setup(struct nf_conn *ct, | |
633 | enum nf_nat_manip_type manip, | |
39938324 | 634 | const struct nlattr *attr) |
e6a7d3c0 | 635 | { |
cbc9f2f4 | 636 | struct nf_nat_ipv4_range range; |
e6a7d3c0 PNA |
637 | |
638 | if (nfnetlink_parse_nat(attr, ct, &range) < 0) | |
639 | return -EINVAL; | |
640 | if (nf_nat_initialized(ct, manip)) | |
641 | return -EEXIST; | |
642 | ||
643 | return nf_nat_setup_info(ct, &range, manip); | |
644 | } | |
645 | #else | |
646 | static int | |
647 | nfnetlink_parse_nat_setup(struct nf_conn *ct, | |
648 | enum nf_nat_manip_type manip, | |
39938324 | 649 | const struct nlattr *attr) |
e6a7d3c0 PNA |
650 | { |
651 | return -EOPNOTSUPP; | |
652 | } | |
653 | #endif | |
654 | ||
0c4c9288 AD |
655 | static int __net_init nf_nat_net_init(struct net *net) |
656 | { | |
d696c7bd PM |
657 | /* Leave them the same for the moment. */ |
658 | net->ipv4.nat_htable_size = net->ct.htable_size; | |
d862a662 | 659 | net->ipv4.nat_bysource = nf_ct_alloc_hashtable(&net->ipv4.nat_htable_size, 0); |
0c4c9288 AD |
660 | if (!net->ipv4.nat_bysource) |
661 | return -ENOMEM; | |
662 | return 0; | |
663 | } | |
664 | ||
665 | /* Clear NAT section of all conntracks, in case we're loaded again. */ | |
666 | static int clean_nat(struct nf_conn *i, void *data) | |
667 | { | |
668 | struct nf_conn_nat *nat = nfct_nat(i); | |
669 | ||
670 | if (!nat) | |
671 | return 0; | |
672 | memset(nat, 0, sizeof(*nat)); | |
673 | i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST); | |
674 | return 0; | |
675 | } | |
676 | ||
677 | static void __net_exit nf_nat_net_exit(struct net *net) | |
678 | { | |
679 | nf_ct_iterate_cleanup(net, &clean_nat, NULL); | |
680 | synchronize_rcu(); | |
d862a662 | 681 | nf_ct_free_hashtable(net->ipv4.nat_bysource, net->ipv4.nat_htable_size); |
0c4c9288 AD |
682 | } |
683 | ||
684 | static struct pernet_operations nf_nat_net_ops = { | |
685 | .init = nf_nat_net_init, | |
686 | .exit = nf_nat_net_exit, | |
687 | }; | |
688 | ||
544d5c7d PNA |
689 | static struct nf_ct_helper_expectfn follow_master_nat = { |
690 | .name = "nat-follow-master", | |
691 | .expectfn = nf_nat_follow_master, | |
692 | }; | |
693 | ||
5b1158e9 JK |
694 | static int __init nf_nat_init(void) |
695 | { | |
696 | size_t i; | |
2d59e5ca YK |
697 | int ret; |
698 | ||
475959d4 JE |
699 | need_ipv4_conntrack(); |
700 | ||
2d59e5ca YK |
701 | ret = nf_ct_extend_register(&nat_extend); |
702 | if (ret < 0) { | |
703 | printk(KERN_ERR "nf_nat_core: Unable to register extension\n"); | |
704 | return ret; | |
705 | } | |
5b1158e9 | 706 | |
0c4c9288 AD |
707 | ret = register_pernet_subsys(&nf_nat_net_ops); |
708 | if (ret < 0) | |
2d59e5ca | 709 | goto cleanup_extend; |
5b1158e9 JK |
710 | |
711 | /* Sew in builtin protocols. */ | |
02502f62 | 712 | spin_lock_bh(&nf_nat_lock); |
5b1158e9 | 713 | for (i = 0; i < MAX_IP_NAT_PROTO; i++) |
a9b3cd7f SH |
714 | RCU_INIT_POINTER(nf_nat_protos[i], &nf_nat_unknown_protocol); |
715 | RCU_INIT_POINTER(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp); | |
716 | RCU_INIT_POINTER(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp); | |
717 | RCU_INIT_POINTER(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp); | |
02502f62 | 718 | spin_unlock_bh(&nf_nat_lock); |
5b1158e9 | 719 | |
5b1158e9 | 720 | /* Initialize fake conntrack so that NAT will skip it */ |
5bfddbd4 | 721 | nf_ct_untracked_status_or(IPS_NAT_DONE_MASK); |
5b1158e9 JK |
722 | |
723 | l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET); | |
dd13b010 | 724 | |
544d5c7d PNA |
725 | nf_ct_helper_expectfn_register(&follow_master_nat); |
726 | ||
dd13b010 | 727 | BUG_ON(nf_nat_seq_adjust_hook != NULL); |
a9b3cd7f | 728 | RCU_INIT_POINTER(nf_nat_seq_adjust_hook, nf_nat_seq_adjust); |
e6a7d3c0 | 729 | BUG_ON(nfnetlink_parse_nat_setup_hook != NULL); |
a9b3cd7f | 730 | RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook, |
e6a7d3c0 | 731 | nfnetlink_parse_nat_setup); |
f9dd09c7 | 732 | BUG_ON(nf_ct_nat_offset != NULL); |
a9b3cd7f | 733 | RCU_INIT_POINTER(nf_ct_nat_offset, nf_nat_get_offset); |
5b1158e9 | 734 | return 0; |
2d59e5ca YK |
735 | |
736 | cleanup_extend: | |
737 | nf_ct_extend_unregister(&nat_extend); | |
738 | return ret; | |
5b1158e9 JK |
739 | } |
740 | ||
5b1158e9 JK |
741 | static void __exit nf_nat_cleanup(void) |
742 | { | |
0c4c9288 | 743 | unregister_pernet_subsys(&nf_nat_net_ops); |
5b1158e9 | 744 | nf_ct_l3proto_put(l3proto); |
2d59e5ca | 745 | nf_ct_extend_unregister(&nat_extend); |
544d5c7d | 746 | nf_ct_helper_expectfn_unregister(&follow_master_nat); |
a9b3cd7f SH |
747 | RCU_INIT_POINTER(nf_nat_seq_adjust_hook, NULL); |
748 | RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook, NULL); | |
749 | RCU_INIT_POINTER(nf_ct_nat_offset, NULL); | |
dd13b010 | 750 | synchronize_net(); |
5b1158e9 JK |
751 | } |
752 | ||
753 | MODULE_LICENSE("GPL"); | |
e6a7d3c0 | 754 | MODULE_ALIAS("nf-nat-ipv4"); |
5b1158e9 JK |
755 | |
756 | module_init(nf_nat_init); | |
757 | module_exit(nf_nat_cleanup); |