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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Transparent proxy support for Linux/iptables
4 *
5 * Copyright (c) 2006-2010 BalaBit IT Ltd.
6 * Author: Balazs Scheidler, Krisztian Kovacs
7 */
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9#include <linux/module.h>
10#include <linux/skbuff.h>
11#include <linux/ip.h>
12#include <net/checksum.h>
13#include <net/udp.h>
14#include <net/tcp.h>
15#include <net/inet_sock.h>
16#include <net/inet_hashtables.h>
17#include <linux/inetdevice.h>
18#include <linux/netfilter/x_tables.h>
19#include <linux/netfilter_ipv4/ip_tables.h>
20
21#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
22
23#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
24#define XT_TPROXY_HAVE_IPV6 1
25#include <net/if_inet6.h>
26#include <net/addrconf.h>
27#include <net/inet6_hashtables.h>
28#include <linux/netfilter_ipv6/ip6_tables.h>
29#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
30#endif
31
32#include <net/netfilter/nf_tproxy.h>
33#include <linux/netfilter/xt_TPROXY.h>
34
35static unsigned int
36tproxy_tg4(struct net *net, struct sk_buff *skb, __be32 laddr, __be16 lport,
37 u_int32_t mark_mask, u_int32_t mark_value)
38{
39 const struct iphdr *iph = ip_hdr(skb);
40 struct udphdr _hdr, *hp;
41 struct sock *sk;
42
43 hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
44 if (hp == NULL)
45 return NF_DROP;
46
47 /* check if there's an ongoing connection on the packet
48 * addresses, this happens if the redirect already happened
49 * and the current packet belongs to an already established
50 * connection */
51 sk = nf_tproxy_get_sock_v4(net, skb, iph->protocol,
52 iph->saddr, iph->daddr,
53 hp->source, hp->dest,
54 skb->dev, NF_TPROXY_LOOKUP_ESTABLISHED);
55
56 laddr = nf_tproxy_laddr4(skb, laddr, iph->daddr);
57 if (!lport)
58 lport = hp->dest;
59
60 /* UDP has no TCP_TIME_WAIT state, so we never enter here */
61 if (sk && sk->sk_state == TCP_TIME_WAIT)
62 /* reopening a TIME_WAIT connection needs special handling */
63 sk = nf_tproxy_handle_time_wait4(net, skb, laddr, lport, sk);
64 else if (!sk)
65 /* no, there's no established connection, check if
66 * there's a listener on the redirected addr/port */
67 sk = nf_tproxy_get_sock_v4(net, skb, iph->protocol,
68 iph->saddr, laddr,
69 hp->source, lport,
70 skb->dev, NF_TPROXY_LOOKUP_LISTENER);
71
72 /* NOTE: assign_sock consumes our sk reference */
73 if (sk && nf_tproxy_sk_is_transparent(sk)) {
74 /* This should be in a separate target, but we don't do multiple
75 targets on the same rule yet */
76 skb->mark = (skb->mark & ~mark_mask) ^ mark_value;
77
78 pr_debug("redirecting: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
79 iph->protocol, &iph->daddr, ntohs(hp->dest),
80 &laddr, ntohs(lport), skb->mark);
81
82 nf_tproxy_assign_sock(skb, sk);
83 return NF_ACCEPT;
84 }
85
86 pr_debug("no socket, dropping: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
87 iph->protocol, &iph->saddr, ntohs(hp->source),
88 &iph->daddr, ntohs(hp->dest), skb->mark);
89 return NF_DROP;
90}
91
92static unsigned int
93tproxy_tg4_v0(struct sk_buff *skb, const struct xt_action_param *par)
94{
95 const struct xt_tproxy_target_info *tgi = par->targinfo;
96
97 return tproxy_tg4(xt_net(par), skb, tgi->laddr, tgi->lport,
98 tgi->mark_mask, tgi->mark_value);
99}
100
101static unsigned int
102tproxy_tg4_v1(struct sk_buff *skb, const struct xt_action_param *par)
103{
104 const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
105
106 return tproxy_tg4(xt_net(par), skb, tgi->laddr.ip, tgi->lport,
107 tgi->mark_mask, tgi->mark_value);
108}
109
110#ifdef XT_TPROXY_HAVE_IPV6
111
112static unsigned int
113tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
114{
115 const struct ipv6hdr *iph = ipv6_hdr(skb);
116 const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
117 struct udphdr _hdr, *hp;
118 struct sock *sk;
119 const struct in6_addr *laddr;
120 __be16 lport;
121 int thoff = 0;
122 int tproto;
123
124 tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL);
125 if (tproto < 0) {
126 pr_debug("unable to find transport header in IPv6 packet, dropping\n");
127 return NF_DROP;
128 }
129
130 hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
131 if (hp == NULL) {
132 pr_debug("unable to grab transport header contents in IPv6 packet, dropping\n");
133 return NF_DROP;
134 }
135
136 /* check if there's an ongoing connection on the packet
137 * addresses, this happens if the redirect already happened
138 * and the current packet belongs to an already established
139 * connection */
140 sk = nf_tproxy_get_sock_v6(xt_net(par), skb, thoff, tproto,
141 &iph->saddr, &iph->daddr,
142 hp->source, hp->dest,
143 xt_in(par), NF_TPROXY_LOOKUP_ESTABLISHED);
144
145 laddr = nf_tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr);
146 lport = tgi->lport ? tgi->lport : hp->dest;
147
148 /* UDP has no TCP_TIME_WAIT state, so we never enter here */
149 if (sk && sk->sk_state == TCP_TIME_WAIT) {
150 const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
151 /* reopening a TIME_WAIT connection needs special handling */
152 sk = nf_tproxy_handle_time_wait6(skb, tproto, thoff,
153 xt_net(par),
154 &tgi->laddr.in6,
155 tgi->lport,
156 sk);
157 }
158 else if (!sk)
159 /* no there's no established connection, check if
160 * there's a listener on the redirected addr/port */
161 sk = nf_tproxy_get_sock_v6(xt_net(par), skb, thoff,
162 tproto, &iph->saddr, laddr,
163 hp->source, lport,
164 xt_in(par), NF_TPROXY_LOOKUP_LISTENER);
165
166 /* NOTE: assign_sock consumes our sk reference */
167 if (sk && nf_tproxy_sk_is_transparent(sk)) {
168 /* This should be in a separate target, but we don't do multiple
169 targets on the same rule yet */
170 skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;
171
172 pr_debug("redirecting: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
173 tproto, &iph->saddr, ntohs(hp->source),
174 laddr, ntohs(lport), skb->mark);
175
176 nf_tproxy_assign_sock(skb, sk);
177 return NF_ACCEPT;
178 }
179
180 pr_debug("no socket, dropping: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
181 tproto, &iph->saddr, ntohs(hp->source),
182 &iph->daddr, ntohs(hp->dest), skb->mark);
183
184 return NF_DROP;
185}
186
187static int tproxy_tg6_check(const struct xt_tgchk_param *par)
188{
189 const struct ip6t_ip6 *i = par->entryinfo;
190 int err;
191
192 err = nf_defrag_ipv6_enable(par->net);
193 if (err)
194 return err;
195
196 if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP) &&
197 !(i->invflags & IP6T_INV_PROTO))
198 return 0;
199
200 pr_info_ratelimited("Can be used only with -p tcp or -p udp\n");
201 return -EINVAL;
202}
203
204static void tproxy_tg6_destroy(const struct xt_tgdtor_param *par)
205{
206 nf_defrag_ipv6_disable(par->net);
207}
208#endif
209
210static int tproxy_tg4_check(const struct xt_tgchk_param *par)
211{
212 const struct ipt_ip *i = par->entryinfo;
213 int err;
214
215 err = nf_defrag_ipv4_enable(par->net);
216 if (err)
217 return err;
218
219 if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP)
220 && !(i->invflags & IPT_INV_PROTO))
221 return 0;
222
223 pr_info_ratelimited("Can be used only with -p tcp or -p udp\n");
224 return -EINVAL;
225}
226
227static void tproxy_tg4_destroy(const struct xt_tgdtor_param *par)
228{
229 nf_defrag_ipv4_disable(par->net);
230}
231
232static struct xt_target tproxy_tg_reg[] __read_mostly = {
233 {
234 .name = "TPROXY",
235 .family = NFPROTO_IPV4,
236 .table = "mangle",
237 .target = tproxy_tg4_v0,
238 .revision = 0,
239 .targetsize = sizeof(struct xt_tproxy_target_info),
240 .checkentry = tproxy_tg4_check,
241 .destroy = tproxy_tg4_destroy,
242 .hooks = 1 << NF_INET_PRE_ROUTING,
243 .me = THIS_MODULE,
244 },
245 {
246 .name = "TPROXY",
247 .family = NFPROTO_IPV4,
248 .table = "mangle",
249 .target = tproxy_tg4_v1,
250 .revision = 1,
251 .targetsize = sizeof(struct xt_tproxy_target_info_v1),
252 .checkentry = tproxy_tg4_check,
253 .destroy = tproxy_tg4_destroy,
254 .hooks = 1 << NF_INET_PRE_ROUTING,
255 .me = THIS_MODULE,
256 },
257#ifdef XT_TPROXY_HAVE_IPV6
258 {
259 .name = "TPROXY",
260 .family = NFPROTO_IPV6,
261 .table = "mangle",
262 .target = tproxy_tg6_v1,
263 .revision = 1,
264 .targetsize = sizeof(struct xt_tproxy_target_info_v1),
265 .checkentry = tproxy_tg6_check,
266 .destroy = tproxy_tg6_destroy,
267 .hooks = 1 << NF_INET_PRE_ROUTING,
268 .me = THIS_MODULE,
269 },
270#endif
271
272};
273
274static int __init tproxy_tg_init(void)
275{
276 return xt_register_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
277}
278
279static void __exit tproxy_tg_exit(void)
280{
281 xt_unregister_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
282}
283
284module_init(tproxy_tg_init);
285module_exit(tproxy_tg_exit);
286MODULE_LICENSE("GPL");
287MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
288MODULE_DESCRIPTION("Netfilter transparent proxy (TPROXY) target module.");
289MODULE_ALIAS("ipt_TPROXY");
290MODULE_ALIAS("ip6t_TPROXY");
1/*
2 * Transparent proxy support for Linux/iptables
3 *
4 * Copyright (c) 2006-2010 BalaBit IT Ltd.
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 */
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
18#include <net/inet_sock.h>
19#include <linux/inetdevice.h>
20#include <linux/netfilter/x_tables.h>
21#include <linux/netfilter_ipv4/ip_tables.h>
22
23#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
24
25#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
26#define XT_TPROXY_HAVE_IPV6 1
27#include <net/if_inet6.h>
28#include <net/addrconf.h>
29#include <linux/netfilter_ipv6/ip6_tables.h>
30#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
31#endif
32
33#include <net/netfilter/nf_tproxy_core.h>
34#include <linux/netfilter/xt_TPROXY.h>
35
36static bool tproxy_sk_is_transparent(struct sock *sk)
37{
38 if (sk->sk_state != TCP_TIME_WAIT) {
39 if (inet_sk(sk)->transparent)
40 return true;
41 sock_put(sk);
42 } else {
43 if (inet_twsk(sk)->tw_transparent)
44 return true;
45 inet_twsk_put(inet_twsk(sk));
46 }
47 return false;
48}
49
50static inline __be32
51tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr)
52{
53 struct in_device *indev;
54 __be32 laddr;
55
56 if (user_laddr)
57 return user_laddr;
58
59 laddr = 0;
60 rcu_read_lock();
61 indev = __in_dev_get_rcu(skb->dev);
62 for_primary_ifa(indev) {
63 laddr = ifa->ifa_local;
64 break;
65 } endfor_ifa(indev);
66 rcu_read_unlock();
67
68 return laddr ? laddr : daddr;
69}
70
71/**
72 * tproxy_handle_time_wait4() - handle IPv4 TCP TIME_WAIT reopen redirections
73 * @skb: The skb being processed.
74 * @laddr: IPv4 address to redirect to or zero.
75 * @lport: TCP port to redirect to or zero.
76 * @sk: The TIME_WAIT TCP socket found by the lookup.
77 *
78 * We have to handle SYN packets arriving to TIME_WAIT sockets
79 * differently: instead of reopening the connection we should rather
80 * redirect the new connection to the proxy if there's a listener
81 * socket present.
82 *
83 * tproxy_handle_time_wait4() consumes the socket reference passed in.
84 *
85 * Returns the listener socket if there's one, the TIME_WAIT socket if
86 * no such listener is found, or NULL if the TCP header is incomplete.
87 */
88static struct sock *
89tproxy_handle_time_wait4(struct sk_buff *skb, __be32 laddr, __be16 lport,
90 struct sock *sk)
91{
92 const struct iphdr *iph = ip_hdr(skb);
93 struct tcphdr _hdr, *hp;
94
95 hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
96 if (hp == NULL) {
97 inet_twsk_put(inet_twsk(sk));
98 return NULL;
99 }
100
101 if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
102 /* SYN to a TIME_WAIT socket, we'd rather redirect it
103 * to a listener socket if there's one */
104 struct sock *sk2;
105
106 sk2 = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
107 iph->saddr, laddr ? laddr : iph->daddr,
108 hp->source, lport ? lport : hp->dest,
109 skb->dev, NFT_LOOKUP_LISTENER);
110 if (sk2) {
111 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
112 inet_twsk_put(inet_twsk(sk));
113 sk = sk2;
114 }
115 }
116
117 return sk;
118}
119
120static unsigned int
121tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
122 u_int32_t mark_mask, u_int32_t mark_value)
123{
124 const struct iphdr *iph = ip_hdr(skb);
125 struct udphdr _hdr, *hp;
126 struct sock *sk;
127
128 hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
129 if (hp == NULL)
130 return NF_DROP;
131
132 /* check if there's an ongoing connection on the packet
133 * addresses, this happens if the redirect already happened
134 * and the current packet belongs to an already established
135 * connection */
136 sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
137 iph->saddr, iph->daddr,
138 hp->source, hp->dest,
139 skb->dev, NFT_LOOKUP_ESTABLISHED);
140
141 laddr = tproxy_laddr4(skb, laddr, iph->daddr);
142 if (!lport)
143 lport = hp->dest;
144
145 /* UDP has no TCP_TIME_WAIT state, so we never enter here */
146 if (sk && sk->sk_state == TCP_TIME_WAIT)
147 /* reopening a TIME_WAIT connection needs special handling */
148 sk = tproxy_handle_time_wait4(skb, laddr, lport, sk);
149 else if (!sk)
150 /* no, there's no established connection, check if
151 * there's a listener on the redirected addr/port */
152 sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
153 iph->saddr, laddr,
154 hp->source, lport,
155 skb->dev, NFT_LOOKUP_LISTENER);
156
157 /* NOTE: assign_sock consumes our sk reference */
158 if (sk && tproxy_sk_is_transparent(sk)) {
159 /* This should be in a separate target, but we don't do multiple
160 targets on the same rule yet */
161 skb->mark = (skb->mark & ~mark_mask) ^ mark_value;
162
163 pr_debug("redirecting: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
164 iph->protocol, &iph->daddr, ntohs(hp->dest),
165 &laddr, ntohs(lport), skb->mark);
166
167 nf_tproxy_assign_sock(skb, sk);
168 return NF_ACCEPT;
169 }
170
171 pr_debug("no socket, dropping: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
172 iph->protocol, &iph->saddr, ntohs(hp->source),
173 &iph->daddr, ntohs(hp->dest), skb->mark);
174 return NF_DROP;
175}
176
177static unsigned int
178tproxy_tg4_v0(struct sk_buff *skb, const struct xt_action_param *par)
179{
180 const struct xt_tproxy_target_info *tgi = par->targinfo;
181
182 return tproxy_tg4(skb, tgi->laddr, tgi->lport, tgi->mark_mask, tgi->mark_value);
183}
184
185static unsigned int
186tproxy_tg4_v1(struct sk_buff *skb, const struct xt_action_param *par)
187{
188 const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
189
190 return tproxy_tg4(skb, tgi->laddr.ip, tgi->lport, tgi->mark_mask, tgi->mark_value);
191}
192
193#ifdef XT_TPROXY_HAVE_IPV6
194
195static inline const struct in6_addr *
196tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr,
197 const struct in6_addr *daddr)
198{
199 struct inet6_dev *indev;
200 struct inet6_ifaddr *ifa;
201 struct in6_addr *laddr;
202
203 if (!ipv6_addr_any(user_laddr))
204 return user_laddr;
205 laddr = NULL;
206
207 rcu_read_lock();
208 indev = __in6_dev_get(skb->dev);
209 if (indev)
210 list_for_each_entry(ifa, &indev->addr_list, if_list) {
211 if (ifa->flags & (IFA_F_TENTATIVE | IFA_F_DEPRECATED))
212 continue;
213
214 laddr = &ifa->addr;
215 break;
216 }
217 rcu_read_unlock();
218
219 return laddr ? laddr : daddr;
220}
221
222/**
223 * tproxy_handle_time_wait6() - handle IPv6 TCP TIME_WAIT reopen redirections
224 * @skb: The skb being processed.
225 * @tproto: Transport protocol.
226 * @thoff: Transport protocol header offset.
227 * @par: Iptables target parameters.
228 * @sk: The TIME_WAIT TCP socket found by the lookup.
229 *
230 * We have to handle SYN packets arriving to TIME_WAIT sockets
231 * differently: instead of reopening the connection we should rather
232 * redirect the new connection to the proxy if there's a listener
233 * socket present.
234 *
235 * tproxy_handle_time_wait6() consumes the socket reference passed in.
236 *
237 * Returns the listener socket if there's one, the TIME_WAIT socket if
238 * no such listener is found, or NULL if the TCP header is incomplete.
239 */
240static struct sock *
241tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
242 const struct xt_action_param *par,
243 struct sock *sk)
244{
245 const struct ipv6hdr *iph = ipv6_hdr(skb);
246 struct tcphdr _hdr, *hp;
247 const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
248
249 hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
250 if (hp == NULL) {
251 inet_twsk_put(inet_twsk(sk));
252 return NULL;
253 }
254
255 if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
256 /* SYN to a TIME_WAIT socket, we'd rather redirect it
257 * to a listener socket if there's one */
258 struct sock *sk2;
259
260 sk2 = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
261 &iph->saddr,
262 tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr),
263 hp->source,
264 tgi->lport ? tgi->lport : hp->dest,
265 skb->dev, NFT_LOOKUP_LISTENER);
266 if (sk2) {
267 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
268 inet_twsk_put(inet_twsk(sk));
269 sk = sk2;
270 }
271 }
272
273 return sk;
274}
275
276static unsigned int
277tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
278{
279 const struct ipv6hdr *iph = ipv6_hdr(skb);
280 const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
281 struct udphdr _hdr, *hp;
282 struct sock *sk;
283 const struct in6_addr *laddr;
284 __be16 lport;
285 int thoff;
286 int tproto;
287
288 tproto = ipv6_find_hdr(skb, &thoff, -1, NULL);
289 if (tproto < 0) {
290 pr_debug("unable to find transport header in IPv6 packet, dropping\n");
291 return NF_DROP;
292 }
293
294 hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
295 if (hp == NULL) {
296 pr_debug("unable to grab transport header contents in IPv6 packet, dropping\n");
297 return NF_DROP;
298 }
299
300 /* check if there's an ongoing connection on the packet
301 * addresses, this happens if the redirect already happened
302 * and the current packet belongs to an already established
303 * connection */
304 sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
305 &iph->saddr, &iph->daddr,
306 hp->source, hp->dest,
307 par->in, NFT_LOOKUP_ESTABLISHED);
308
309 laddr = tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr);
310 lport = tgi->lport ? tgi->lport : hp->dest;
311
312 /* UDP has no TCP_TIME_WAIT state, so we never enter here */
313 if (sk && sk->sk_state == TCP_TIME_WAIT)
314 /* reopening a TIME_WAIT connection needs special handling */
315 sk = tproxy_handle_time_wait6(skb, tproto, thoff, par, sk);
316 else if (!sk)
317 /* no there's no established connection, check if
318 * there's a listener on the redirected addr/port */
319 sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
320 &iph->saddr, laddr,
321 hp->source, lport,
322 par->in, NFT_LOOKUP_LISTENER);
323
324 /* NOTE: assign_sock consumes our sk reference */
325 if (sk && tproxy_sk_is_transparent(sk)) {
326 /* This should be in a separate target, but we don't do multiple
327 targets on the same rule yet */
328 skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;
329
330 pr_debug("redirecting: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
331 tproto, &iph->saddr, ntohs(hp->source),
332 laddr, ntohs(lport), skb->mark);
333
334 nf_tproxy_assign_sock(skb, sk);
335 return NF_ACCEPT;
336 }
337
338 pr_debug("no socket, dropping: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
339 tproto, &iph->saddr, ntohs(hp->source),
340 &iph->daddr, ntohs(hp->dest), skb->mark);
341
342 return NF_DROP;
343}
344
345static int tproxy_tg6_check(const struct xt_tgchk_param *par)
346{
347 const struct ip6t_ip6 *i = par->entryinfo;
348
349 if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP)
350 && !(i->flags & IP6T_INV_PROTO))
351 return 0;
352
353 pr_info("Can be used only in combination with "
354 "either -p tcp or -p udp\n");
355 return -EINVAL;
356}
357#endif
358
359static int tproxy_tg4_check(const struct xt_tgchk_param *par)
360{
361 const struct ipt_ip *i = par->entryinfo;
362
363 if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP)
364 && !(i->invflags & IPT_INV_PROTO))
365 return 0;
366
367 pr_info("Can be used only in combination with "
368 "either -p tcp or -p udp\n");
369 return -EINVAL;
370}
371
372static struct xt_target tproxy_tg_reg[] __read_mostly = {
373 {
374 .name = "TPROXY",
375 .family = NFPROTO_IPV4,
376 .table = "mangle",
377 .target = tproxy_tg4_v0,
378 .revision = 0,
379 .targetsize = sizeof(struct xt_tproxy_target_info),
380 .checkentry = tproxy_tg4_check,
381 .hooks = 1 << NF_INET_PRE_ROUTING,
382 .me = THIS_MODULE,
383 },
384 {
385 .name = "TPROXY",
386 .family = NFPROTO_IPV4,
387 .table = "mangle",
388 .target = tproxy_tg4_v1,
389 .revision = 1,
390 .targetsize = sizeof(struct xt_tproxy_target_info_v1),
391 .checkentry = tproxy_tg4_check,
392 .hooks = 1 << NF_INET_PRE_ROUTING,
393 .me = THIS_MODULE,
394 },
395#ifdef XT_TPROXY_HAVE_IPV6
396 {
397 .name = "TPROXY",
398 .family = NFPROTO_IPV6,
399 .table = "mangle",
400 .target = tproxy_tg6_v1,
401 .revision = 1,
402 .targetsize = sizeof(struct xt_tproxy_target_info_v1),
403 .checkentry = tproxy_tg6_check,
404 .hooks = 1 << NF_INET_PRE_ROUTING,
405 .me = THIS_MODULE,
406 },
407#endif
408
409};
410
411static int __init tproxy_tg_init(void)
412{
413 nf_defrag_ipv4_enable();
414#ifdef XT_TPROXY_HAVE_IPV6
415 nf_defrag_ipv6_enable();
416#endif
417
418 return xt_register_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
419}
420
421static void __exit tproxy_tg_exit(void)
422{
423 xt_unregister_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
424}
425
426module_init(tproxy_tg_init);
427module_exit(tproxy_tg_exit);
428MODULE_LICENSE("GPL");
429MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
430MODULE_DESCRIPTION("Netfilter transparent proxy (TPROXY) target module.");
431MODULE_ALIAS("ipt_TPROXY");
432MODULE_ALIAS("ip6t_TPROXY");