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e8439270 KK |
1 | /* |
2 | * Transparent proxy support for Linux/iptables | |
3 | * | |
6ad78893 | 4 | * Copyright (c) 2006-2010 BalaBit IT Ltd. |
e8439270 KK |
5 | * Author: Balazs Scheidler, Krisztian Kovacs |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | */ | |
ff67e4e4 | 12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
e8439270 KK |
13 | #include <linux/module.h> |
14 | #include <linux/skbuff.h> | |
15 | #include <linux/ip.h> | |
16 | #include <net/checksum.h> | |
17 | #include <net/udp.h> | |
93742cf8 | 18 | #include <net/tcp.h> |
e8439270 | 19 | #include <net/inet_sock.h> |
93742cf8 | 20 | #include <net/inet_hashtables.h> |
cc6eb433 | 21 | #include <linux/inetdevice.h> |
e8439270 KK |
22 | #include <linux/netfilter/x_tables.h> |
23 | #include <linux/netfilter_ipv4/ip_tables.h> | |
e8439270 KK |
24 | |
25 | #include <net/netfilter/ipv4/nf_defrag_ipv4.h> | |
f6318e55 | 26 | |
c0cd1156 | 27 | #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) |
f6318e55 | 28 | #define XT_TPROXY_HAVE_IPV6 1 |
cc6eb433 BS |
29 | #include <net/if_inet6.h> |
30 | #include <net/addrconf.h> | |
93742cf8 | 31 | #include <net/inet6_hashtables.h> |
cc6eb433 | 32 | #include <linux/netfilter_ipv6/ip6_tables.h> |
6ad78893 | 33 | #include <net/netfilter/ipv6/nf_defrag_ipv6.h> |
cc6eb433 BS |
34 | #endif |
35 | ||
cc6eb433 BS |
36 | #include <linux/netfilter/xt_TPROXY.h> |
37 | ||
93742cf8 FW |
38 | enum nf_tproxy_lookup_t { |
39 | NFT_LOOKUP_LISTENER, | |
40 | NFT_LOOKUP_ESTABLISHED, | |
41 | }; | |
42 | ||
d503b30b FW |
43 | static bool tproxy_sk_is_transparent(struct sock *sk) |
44 | { | |
8b580147 ED |
45 | switch (sk->sk_state) { |
46 | case TCP_TIME_WAIT: | |
d503b30b FW |
47 | if (inet_twsk(sk)->tw_transparent) |
48 | return true; | |
8b580147 ED |
49 | break; |
50 | case TCP_NEW_SYN_RECV: | |
51 | if (inet_rsk(inet_reqsk(sk))->no_srccheck) | |
52 | return true; | |
53 | break; | |
54 | default: | |
55 | if (inet_sk(sk)->transparent) | |
56 | return true; | |
d503b30b | 57 | } |
8b580147 ED |
58 | |
59 | sock_gen_put(sk); | |
d503b30b FW |
60 | return false; |
61 | } | |
62 | ||
cc6eb433 BS |
63 | static inline __be32 |
64 | tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr) | |
65 | { | |
66 | struct in_device *indev; | |
67 | __be32 laddr; | |
68 | ||
69 | if (user_laddr) | |
70 | return user_laddr; | |
71 | ||
72 | laddr = 0; | |
73 | rcu_read_lock(); | |
74 | indev = __in_dev_get_rcu(skb->dev); | |
75 | for_primary_ifa(indev) { | |
76 | laddr = ifa->ifa_local; | |
77 | break; | |
78 | } endfor_ifa(indev); | |
79 | rcu_read_unlock(); | |
80 | ||
81 | return laddr ? laddr : daddr; | |
82 | } | |
e8439270 | 83 | |
93742cf8 FW |
84 | /* |
85 | * This is used when the user wants to intercept a connection matching | |
86 | * an explicit iptables rule. In this case the sockets are assumed | |
87 | * matching in preference order: | |
88 | * | |
89 | * - match: if there's a fully established connection matching the | |
90 | * _packet_ tuple, it is returned, assuming the redirection | |
91 | * already took place and we process a packet belonging to an | |
92 | * established connection | |
93 | * | |
94 | * - match: if there's a listening socket matching the redirection | |
95 | * (e.g. on-port & on-ip of the connection), it is returned, | |
96 | * regardless if it was bound to 0.0.0.0 or an explicit | |
97 | * address. The reasoning is that if there's an explicit rule, it | |
98 | * does not really matter if the listener is bound to an interface | |
99 | * or to 0. The user already stated that he wants redirection | |
100 | * (since he added the rule). | |
101 | * | |
102 | * Please note that there's an overlap between what a TPROXY target | |
103 | * and a socket match will match. Normally if you have both rules the | |
104 | * "socket" match will be the first one, effectively all packets | |
105 | * belonging to established connections going through that one. | |
106 | */ | |
107 | static inline struct sock * | |
a583636a CG |
108 | nf_tproxy_get_sock_v4(struct net *net, struct sk_buff *skb, void *hp, |
109 | const u8 protocol, | |
93742cf8 FW |
110 | const __be32 saddr, const __be32 daddr, |
111 | const __be16 sport, const __be16 dport, | |
112 | const struct net_device *in, | |
113 | const enum nf_tproxy_lookup_t lookup_type) | |
114 | { | |
115 | struct sock *sk; | |
a583636a | 116 | struct tcphdr *tcph; |
93742cf8 FW |
117 | |
118 | switch (protocol) { | |
119 | case IPPROTO_TCP: | |
120 | switch (lookup_type) { | |
121 | case NFT_LOOKUP_LISTENER: | |
a583636a CG |
122 | tcph = hp; |
123 | sk = inet_lookup_listener(net, &tcp_hashinfo, skb, | |
124 | ip_hdrlen(skb) + | |
125 | __tcp_hdrlen(tcph), | |
93742cf8 FW |
126 | saddr, sport, |
127 | daddr, dport, | |
128 | in->ifindex); | |
129 | ||
dcbe3590 ED |
130 | if (sk && !atomic_inc_not_zero(&sk->sk_refcnt)) |
131 | sk = NULL; | |
93742cf8 FW |
132 | /* NOTE: we return listeners even if bound to |
133 | * 0.0.0.0, those are filtered out in | |
134 | * xt_socket, since xt_TPROXY needs 0 bound | |
135 | * listeners too | |
136 | */ | |
137 | break; | |
138 | case NFT_LOOKUP_ESTABLISHED: | |
139 | sk = inet_lookup_established(net, &tcp_hashinfo, | |
140 | saddr, sport, daddr, dport, | |
141 | in->ifindex); | |
142 | break; | |
143 | default: | |
144 | BUG(); | |
145 | } | |
146 | break; | |
147 | case IPPROTO_UDP: | |
148 | sk = udp4_lib_lookup(net, saddr, sport, daddr, dport, | |
149 | in->ifindex); | |
150 | if (sk) { | |
151 | int connected = (sk->sk_state == TCP_ESTABLISHED); | |
152 | int wildcard = (inet_sk(sk)->inet_rcv_saddr == 0); | |
153 | ||
154 | /* NOTE: we return listeners even if bound to | |
155 | * 0.0.0.0, those are filtered out in | |
156 | * xt_socket, since xt_TPROXY needs 0 bound | |
157 | * listeners too | |
158 | */ | |
159 | if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) || | |
160 | (lookup_type == NFT_LOOKUP_LISTENER && connected)) { | |
161 | sock_put(sk); | |
162 | sk = NULL; | |
163 | } | |
164 | } | |
165 | break; | |
166 | default: | |
167 | WARN_ON(1); | |
168 | sk = NULL; | |
169 | } | |
170 | ||
171 | pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, lookup type: %d, sock %p\n", | |
172 | protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), lookup_type, sk); | |
173 | ||
174 | return sk; | |
175 | } | |
176 | ||
d8b3bfc2 | 177 | #ifdef XT_TPROXY_HAVE_IPV6 |
93742cf8 | 178 | static inline struct sock * |
a583636a CG |
179 | nf_tproxy_get_sock_v6(struct net *net, struct sk_buff *skb, int thoff, void *hp, |
180 | const u8 protocol, | |
93742cf8 FW |
181 | const struct in6_addr *saddr, const struct in6_addr *daddr, |
182 | const __be16 sport, const __be16 dport, | |
183 | const struct net_device *in, | |
184 | const enum nf_tproxy_lookup_t lookup_type) | |
185 | { | |
186 | struct sock *sk; | |
a583636a | 187 | struct tcphdr *tcph; |
93742cf8 FW |
188 | |
189 | switch (protocol) { | |
190 | case IPPROTO_TCP: | |
191 | switch (lookup_type) { | |
192 | case NFT_LOOKUP_LISTENER: | |
a583636a CG |
193 | tcph = hp; |
194 | sk = inet6_lookup_listener(net, &tcp_hashinfo, skb, | |
195 | thoff + __tcp_hdrlen(tcph), | |
93742cf8 FW |
196 | saddr, sport, |
197 | daddr, ntohs(dport), | |
198 | in->ifindex); | |
199 | ||
dcbe3590 ED |
200 | if (sk && !atomic_inc_not_zero(&sk->sk_refcnt)) |
201 | sk = NULL; | |
93742cf8 FW |
202 | /* NOTE: we return listeners even if bound to |
203 | * 0.0.0.0, those are filtered out in | |
204 | * xt_socket, since xt_TPROXY needs 0 bound | |
205 | * listeners too | |
206 | */ | |
207 | break; | |
208 | case NFT_LOOKUP_ESTABLISHED: | |
209 | sk = __inet6_lookup_established(net, &tcp_hashinfo, | |
210 | saddr, sport, daddr, ntohs(dport), | |
211 | in->ifindex); | |
212 | break; | |
213 | default: | |
214 | BUG(); | |
215 | } | |
216 | break; | |
217 | case IPPROTO_UDP: | |
218 | sk = udp6_lib_lookup(net, saddr, sport, daddr, dport, | |
219 | in->ifindex); | |
220 | if (sk) { | |
221 | int connected = (sk->sk_state == TCP_ESTABLISHED); | |
efe4208f | 222 | int wildcard = ipv6_addr_any(&sk->sk_v6_rcv_saddr); |
93742cf8 FW |
223 | |
224 | /* NOTE: we return listeners even if bound to | |
225 | * 0.0.0.0, those are filtered out in | |
226 | * xt_socket, since xt_TPROXY needs 0 bound | |
227 | * listeners too | |
228 | */ | |
229 | if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) || | |
230 | (lookup_type == NFT_LOOKUP_LISTENER && connected)) { | |
231 | sock_put(sk); | |
232 | sk = NULL; | |
233 | } | |
234 | } | |
235 | break; | |
236 | default: | |
237 | WARN_ON(1); | |
238 | sk = NULL; | |
239 | } | |
240 | ||
241 | pr_debug("tproxy socket lookup: proto %u %pI6:%u -> %pI6:%u, lookup type: %d, sock %p\n", | |
242 | protocol, saddr, ntohs(sport), daddr, ntohs(dport), lookup_type, sk); | |
243 | ||
244 | return sk; | |
245 | } | |
246 | #endif | |
247 | ||
106e4c26 | 248 | /** |
2c53040f | 249 | * tproxy_handle_time_wait4 - handle IPv4 TCP TIME_WAIT reopen redirections |
106e4c26 | 250 | * @skb: The skb being processed. |
6ad78893 BS |
251 | * @laddr: IPv4 address to redirect to or zero. |
252 | * @lport: TCP port to redirect to or zero. | |
106e4c26 BS |
253 | * @sk: The TIME_WAIT TCP socket found by the lookup. |
254 | * | |
255 | * We have to handle SYN packets arriving to TIME_WAIT sockets | |
256 | * differently: instead of reopening the connection we should rather | |
257 | * redirect the new connection to the proxy if there's a listener | |
258 | * socket present. | |
259 | * | |
6ad78893 | 260 | * tproxy_handle_time_wait4() consumes the socket reference passed in. |
106e4c26 BS |
261 | * |
262 | * Returns the listener socket if there's one, the TIME_WAIT socket if | |
263 | * no such listener is found, or NULL if the TCP header is incomplete. | |
264 | */ | |
265 | static struct sock * | |
686c9b50 EB |
266 | tproxy_handle_time_wait4(struct net *net, struct sk_buff *skb, |
267 | __be32 laddr, __be16 lport, struct sock *sk) | |
106e4c26 BS |
268 | { |
269 | const struct iphdr *iph = ip_hdr(skb); | |
106e4c26 BS |
270 | struct tcphdr _hdr, *hp; |
271 | ||
272 | hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr); | |
273 | if (hp == NULL) { | |
274 | inet_twsk_put(inet_twsk(sk)); | |
275 | return NULL; | |
276 | } | |
277 | ||
278 | if (hp->syn && !hp->rst && !hp->ack && !hp->fin) { | |
279 | /* SYN to a TIME_WAIT socket, we'd rather redirect it | |
280 | * to a listener socket if there's one */ | |
281 | struct sock *sk2; | |
282 | ||
a583636a | 283 | sk2 = nf_tproxy_get_sock_v4(net, skb, hp, iph->protocol, |
6ad78893 BS |
284 | iph->saddr, laddr ? laddr : iph->daddr, |
285 | hp->source, lport ? lport : hp->dest, | |
286 | skb->dev, NFT_LOOKUP_LISTENER); | |
287 | if (sk2) { | |
dbe7faa4 | 288 | inet_twsk_deschedule_put(inet_twsk(sk)); |
6ad78893 BS |
289 | sk = sk2; |
290 | } | |
291 | } | |
292 | ||
293 | return sk; | |
294 | } | |
295 | ||
fd158d79 FW |
296 | /* assign a socket to the skb -- consumes sk */ |
297 | static void | |
298 | nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk) | |
299 | { | |
300 | skb_orphan(skb); | |
301 | skb->sk = sk; | |
302 | skb->destructor = sock_edemux; | |
303 | } | |
304 | ||
e8439270 | 305 | static unsigned int |
686c9b50 | 306 | tproxy_tg4(struct net *net, struct sk_buff *skb, __be32 laddr, __be16 lport, |
6ad78893 | 307 | u_int32_t mark_mask, u_int32_t mark_value) |
e8439270 KK |
308 | { |
309 | const struct iphdr *iph = ip_hdr(skb); | |
e8439270 KK |
310 | struct udphdr _hdr, *hp; |
311 | struct sock *sk; | |
312 | ||
313 | hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr); | |
314 | if (hp == NULL) | |
315 | return NF_DROP; | |
316 | ||
6ad78893 BS |
317 | /* check if there's an ongoing connection on the packet |
318 | * addresses, this happens if the redirect already happened | |
319 | * and the current packet belongs to an already established | |
320 | * connection */ | |
a583636a | 321 | sk = nf_tproxy_get_sock_v4(net, skb, hp, iph->protocol, |
106e4c26 BS |
322 | iph->saddr, iph->daddr, |
323 | hp->source, hp->dest, | |
6ad78893 | 324 | skb->dev, NFT_LOOKUP_ESTABLISHED); |
106e4c26 | 325 | |
cc6eb433 BS |
326 | laddr = tproxy_laddr4(skb, laddr, iph->daddr); |
327 | if (!lport) | |
328 | lport = hp->dest; | |
329 | ||
106e4c26 BS |
330 | /* UDP has no TCP_TIME_WAIT state, so we never enter here */ |
331 | if (sk && sk->sk_state == TCP_TIME_WAIT) | |
6ad78893 | 332 | /* reopening a TIME_WAIT connection needs special handling */ |
686c9b50 | 333 | sk = tproxy_handle_time_wait4(net, skb, laddr, lport, sk); |
106e4c26 | 334 | else if (!sk) |
6ad78893 BS |
335 | /* no, there's no established connection, check if |
336 | * there's a listener on the redirected addr/port */ | |
a583636a | 337 | sk = nf_tproxy_get_sock_v4(net, skb, hp, iph->protocol, |
cc6eb433 BS |
338 | iph->saddr, laddr, |
339 | hp->source, lport, | |
6ad78893 BS |
340 | skb->dev, NFT_LOOKUP_LISTENER); |
341 | ||
342 | /* NOTE: assign_sock consumes our sk reference */ | |
d503b30b | 343 | if (sk && tproxy_sk_is_transparent(sk)) { |
6ad78893 BS |
344 | /* This should be in a separate target, but we don't do multiple |
345 | targets on the same rule yet */ | |
346 | skb->mark = (skb->mark & ~mark_mask) ^ mark_value; | |
347 | ||
348 | pr_debug("redirecting: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n", | |
349 | iph->protocol, &iph->daddr, ntohs(hp->dest), | |
350 | &laddr, ntohs(lport), skb->mark); | |
d503b30b FW |
351 | |
352 | nf_tproxy_assign_sock(skb, sk); | |
6ad78893 BS |
353 | return NF_ACCEPT; |
354 | } | |
355 | ||
cc6eb433 BS |
356 | pr_debug("no socket, dropping: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n", |
357 | iph->protocol, &iph->saddr, ntohs(hp->source), | |
358 | &iph->daddr, ntohs(hp->dest), skb->mark); | |
6ad78893 BS |
359 | return NF_DROP; |
360 | } | |
361 | ||
362 | static unsigned int | |
363 | tproxy_tg4_v0(struct sk_buff *skb, const struct xt_action_param *par) | |
364 | { | |
365 | const struct xt_tproxy_target_info *tgi = par->targinfo; | |
366 | ||
613dbd95 PNA |
367 | return tproxy_tg4(xt_net(par), skb, tgi->laddr, tgi->lport, |
368 | tgi->mark_mask, tgi->mark_value); | |
6ad78893 BS |
369 | } |
370 | ||
371 | static unsigned int | |
372 | tproxy_tg4_v1(struct sk_buff *skb, const struct xt_action_param *par) | |
373 | { | |
374 | const struct xt_tproxy_target_info_v1 *tgi = par->targinfo; | |
375 | ||
613dbd95 PNA |
376 | return tproxy_tg4(xt_net(par), skb, tgi->laddr.ip, tgi->lport, |
377 | tgi->mark_mask, tgi->mark_value); | |
6ad78893 BS |
378 | } |
379 | ||
f6318e55 | 380 | #ifdef XT_TPROXY_HAVE_IPV6 |
cc6eb433 BS |
381 | |
382 | static inline const struct in6_addr * | |
383 | tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr, | |
384 | const struct in6_addr *daddr) | |
385 | { | |
386 | struct inet6_dev *indev; | |
387 | struct inet6_ifaddr *ifa; | |
388 | struct in6_addr *laddr; | |
389 | ||
390 | if (!ipv6_addr_any(user_laddr)) | |
391 | return user_laddr; | |
392 | laddr = NULL; | |
393 | ||
394 | rcu_read_lock(); | |
395 | indev = __in6_dev_get(skb->dev); | |
396 | if (indev) | |
397 | list_for_each_entry(ifa, &indev->addr_list, if_list) { | |
398 | if (ifa->flags & (IFA_F_TENTATIVE | IFA_F_DEPRECATED)) | |
399 | continue; | |
400 | ||
401 | laddr = &ifa->addr; | |
402 | break; | |
403 | } | |
404 | rcu_read_unlock(); | |
405 | ||
406 | return laddr ? laddr : daddr; | |
407 | } | |
408 | ||
409 | /** | |
2c53040f | 410 | * tproxy_handle_time_wait6 - handle IPv6 TCP TIME_WAIT reopen redirections |
cc6eb433 BS |
411 | * @skb: The skb being processed. |
412 | * @tproto: Transport protocol. | |
413 | * @thoff: Transport protocol header offset. | |
414 | * @par: Iptables target parameters. | |
415 | * @sk: The TIME_WAIT TCP socket found by the lookup. | |
416 | * | |
417 | * We have to handle SYN packets arriving to TIME_WAIT sockets | |
418 | * differently: instead of reopening the connection we should rather | |
419 | * redirect the new connection to the proxy if there's a listener | |
420 | * socket present. | |
421 | * | |
422 | * tproxy_handle_time_wait6() consumes the socket reference passed in. | |
423 | * | |
424 | * Returns the listener socket if there's one, the TIME_WAIT socket if | |
425 | * no such listener is found, or NULL if the TCP header is incomplete. | |
426 | */ | |
427 | static struct sock * | |
428 | tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff, | |
429 | const struct xt_action_param *par, | |
430 | struct sock *sk) | |
431 | { | |
432 | const struct ipv6hdr *iph = ipv6_hdr(skb); | |
433 | struct tcphdr _hdr, *hp; | |
434 | const struct xt_tproxy_target_info_v1 *tgi = par->targinfo; | |
435 | ||
436 | hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr); | |
437 | if (hp == NULL) { | |
438 | inet_twsk_put(inet_twsk(sk)); | |
439 | return NULL; | |
440 | } | |
441 | ||
442 | if (hp->syn && !hp->rst && !hp->ack && !hp->fin) { | |
443 | /* SYN to a TIME_WAIT socket, we'd rather redirect it | |
444 | * to a listener socket if there's one */ | |
445 | struct sock *sk2; | |
446 | ||
613dbd95 | 447 | sk2 = nf_tproxy_get_sock_v6(xt_net(par), skb, thoff, hp, tproto, |
cc6eb433 BS |
448 | &iph->saddr, |
449 | tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr), | |
450 | hp->source, | |
451 | tgi->lport ? tgi->lport : hp->dest, | |
452 | skb->dev, NFT_LOOKUP_LISTENER); | |
453 | if (sk2) { | |
dbe7faa4 | 454 | inet_twsk_deschedule_put(inet_twsk(sk)); |
cc6eb433 BS |
455 | sk = sk2; |
456 | } | |
457 | } | |
458 | ||
459 | return sk; | |
460 | } | |
461 | ||
6ad78893 BS |
462 | static unsigned int |
463 | tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par) | |
464 | { | |
465 | const struct ipv6hdr *iph = ipv6_hdr(skb); | |
466 | const struct xt_tproxy_target_info_v1 *tgi = par->targinfo; | |
467 | struct udphdr _hdr, *hp; | |
468 | struct sock *sk; | |
cc6eb433 BS |
469 | const struct in6_addr *laddr; |
470 | __be16 lport; | |
84018f55 | 471 | int thoff = 0; |
6ad78893 BS |
472 | int tproto; |
473 | ||
84018f55 | 474 | tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL); |
6ad78893 BS |
475 | if (tproto < 0) { |
476 | pr_debug("unable to find transport header in IPv6 packet, dropping\n"); | |
477 | return NF_DROP; | |
478 | } | |
479 | ||
480 | hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr); | |
481 | if (hp == NULL) { | |
482 | pr_debug("unable to grab transport header contents in IPv6 packet, dropping\n"); | |
483 | return NF_DROP; | |
484 | } | |
485 | ||
486 | /* check if there's an ongoing connection on the packet | |
487 | * addresses, this happens if the redirect already happened | |
488 | * and the current packet belongs to an already established | |
489 | * connection */ | |
613dbd95 | 490 | sk = nf_tproxy_get_sock_v6(xt_net(par), skb, thoff, hp, tproto, |
6ad78893 BS |
491 | &iph->saddr, &iph->daddr, |
492 | hp->source, hp->dest, | |
613dbd95 | 493 | xt_in(par), NFT_LOOKUP_ESTABLISHED); |
6ad78893 | 494 | |
cc6eb433 BS |
495 | laddr = tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr); |
496 | lport = tgi->lport ? tgi->lport : hp->dest; | |
497 | ||
6ad78893 BS |
498 | /* UDP has no TCP_TIME_WAIT state, so we never enter here */ |
499 | if (sk && sk->sk_state == TCP_TIME_WAIT) | |
500 | /* reopening a TIME_WAIT connection needs special handling */ | |
501 | sk = tproxy_handle_time_wait6(skb, tproto, thoff, par, sk); | |
502 | else if (!sk) | |
503 | /* no there's no established connection, check if | |
504 | * there's a listener on the redirected addr/port */ | |
613dbd95 | 505 | sk = nf_tproxy_get_sock_v6(xt_net(par), skb, thoff, hp, |
a583636a | 506 | tproto, &iph->saddr, laddr, |
cc6eb433 | 507 | hp->source, lport, |
613dbd95 | 508 | xt_in(par), NFT_LOOKUP_LISTENER); |
e8439270 KK |
509 | |
510 | /* NOTE: assign_sock consumes our sk reference */ | |
d503b30b | 511 | if (sk && tproxy_sk_is_transparent(sk)) { |
e8439270 KK |
512 | /* This should be in a separate target, but we don't do multiple |
513 | targets on the same rule yet */ | |
514 | skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value; | |
515 | ||
6ad78893 | 516 | pr_debug("redirecting: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n", |
cc6eb433 BS |
517 | tproto, &iph->saddr, ntohs(hp->source), |
518 | laddr, ntohs(lport), skb->mark); | |
d503b30b FW |
519 | |
520 | nf_tproxy_assign_sock(skb, sk); | |
e8439270 KK |
521 | return NF_ACCEPT; |
522 | } | |
523 | ||
6ad78893 | 524 | pr_debug("no socket, dropping: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n", |
cc6eb433 BS |
525 | tproto, &iph->saddr, ntohs(hp->source), |
526 | &iph->daddr, ntohs(hp->dest), skb->mark); | |
527 | ||
e8439270 KK |
528 | return NF_DROP; |
529 | } | |
530 | ||
6ad78893 BS |
531 | static int tproxy_tg6_check(const struct xt_tgchk_param *par) |
532 | { | |
533 | const struct ip6t_ip6 *i = par->entryinfo; | |
834184b1 FW |
534 | int err; |
535 | ||
536 | err = nf_defrag_ipv6_enable(par->net); | |
537 | if (err) | |
538 | return err; | |
6ad78893 | 539 | |
3d8c6dce PNA |
540 | if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP) && |
541 | !(i->invflags & IP6T_INV_PROTO)) | |
6ad78893 BS |
542 | return 0; |
543 | ||
544 | pr_info("Can be used only in combination with " | |
545 | "either -p tcp or -p udp\n"); | |
546 | return -EINVAL; | |
547 | } | |
548 | #endif | |
549 | ||
550 | static int tproxy_tg4_check(const struct xt_tgchk_param *par) | |
e8439270 | 551 | { |
af5d6dc2 | 552 | const struct ipt_ip *i = par->entryinfo; |
834184b1 FW |
553 | int err; |
554 | ||
555 | err = nf_defrag_ipv4_enable(par->net); | |
556 | if (err) | |
557 | return err; | |
e8439270 KK |
558 | |
559 | if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP) | |
560 | && !(i->invflags & IPT_INV_PROTO)) | |
d6b00a53 | 561 | return 0; |
e8439270 | 562 | |
ff67e4e4 | 563 | pr_info("Can be used only in combination with " |
e8439270 | 564 | "either -p tcp or -p udp\n"); |
d6b00a53 | 565 | return -EINVAL; |
e8439270 KK |
566 | } |
567 | ||
6ad78893 BS |
568 | static struct xt_target tproxy_tg_reg[] __read_mostly = { |
569 | { | |
570 | .name = "TPROXY", | |
571 | .family = NFPROTO_IPV4, | |
572 | .table = "mangle", | |
573 | .target = tproxy_tg4_v0, | |
574 | .revision = 0, | |
575 | .targetsize = sizeof(struct xt_tproxy_target_info), | |
576 | .checkentry = tproxy_tg4_check, | |
577 | .hooks = 1 << NF_INET_PRE_ROUTING, | |
578 | .me = THIS_MODULE, | |
579 | }, | |
580 | { | |
581 | .name = "TPROXY", | |
582 | .family = NFPROTO_IPV4, | |
583 | .table = "mangle", | |
584 | .target = tproxy_tg4_v1, | |
585 | .revision = 1, | |
586 | .targetsize = sizeof(struct xt_tproxy_target_info_v1), | |
587 | .checkentry = tproxy_tg4_check, | |
588 | .hooks = 1 << NF_INET_PRE_ROUTING, | |
589 | .me = THIS_MODULE, | |
590 | }, | |
f6318e55 | 591 | #ifdef XT_TPROXY_HAVE_IPV6 |
6ad78893 BS |
592 | { |
593 | .name = "TPROXY", | |
594 | .family = NFPROTO_IPV6, | |
595 | .table = "mangle", | |
596 | .target = tproxy_tg6_v1, | |
597 | .revision = 1, | |
598 | .targetsize = sizeof(struct xt_tproxy_target_info_v1), | |
599 | .checkentry = tproxy_tg6_check, | |
600 | .hooks = 1 << NF_INET_PRE_ROUTING, | |
601 | .me = THIS_MODULE, | |
602 | }, | |
603 | #endif | |
604 | ||
e8439270 KK |
605 | }; |
606 | ||
607 | static int __init tproxy_tg_init(void) | |
608 | { | |
6ad78893 | 609 | return xt_register_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg)); |
e8439270 KK |
610 | } |
611 | ||
612 | static void __exit tproxy_tg_exit(void) | |
613 | { | |
6ad78893 | 614 | xt_unregister_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg)); |
e8439270 KK |
615 | } |
616 | ||
617 | module_init(tproxy_tg_init); | |
618 | module_exit(tproxy_tg_exit); | |
619 | MODULE_LICENSE("GPL"); | |
6ad78893 | 620 | MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs"); |
e8439270 KK |
621 | MODULE_DESCRIPTION("Netfilter transparent proxy (TPROXY) target module."); |
622 | MODULE_ALIAS("ipt_TPROXY"); | |
6ad78893 | 623 | MODULE_ALIAS("ip6t_TPROXY"); |