Loading...
1/*
2 * Copyright (c) 2010 Patrick McHardy <kaber@trash.net>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9#include <linux/module.h>
10#include <linux/gfp.h>
11#include <linux/skbuff.h>
12#include <linux/netfilter_ipv4/ip_tables.h>
13#include <linux/netfilter_ipv6/ip6_tables.h>
14#include <linux/netfilter/x_tables.h>
15#include <linux/netfilter/xt_CT.h>
16#include <net/netfilter/nf_conntrack.h>
17#include <net/netfilter/nf_conntrack_l4proto.h>
18#include <net/netfilter/nf_conntrack_helper.h>
19#include <net/netfilter/nf_conntrack_ecache.h>
20#include <net/netfilter/nf_conntrack_timeout.h>
21#include <net/netfilter/nf_conntrack_zones.h>
22
23static inline int xt_ct_target(struct sk_buff *skb, struct nf_conn *ct)
24{
25 /* Previously seen (loopback)? Ignore. */
26 if (skb->nfct != NULL)
27 return XT_CONTINUE;
28
29 /* special case the untracked ct : we want the percpu object */
30 if (!ct)
31 ct = nf_ct_untracked_get();
32 atomic_inc(&ct->ct_general.use);
33 skb->nfct = &ct->ct_general;
34 skb->nfctinfo = IP_CT_NEW;
35
36 return XT_CONTINUE;
37}
38
39static unsigned int xt_ct_target_v0(struct sk_buff *skb,
40 const struct xt_action_param *par)
41{
42 const struct xt_ct_target_info *info = par->targinfo;
43 struct nf_conn *ct = info->ct;
44
45 return xt_ct_target(skb, ct);
46}
47
48static unsigned int xt_ct_target_v1(struct sk_buff *skb,
49 const struct xt_action_param *par)
50{
51 const struct xt_ct_target_info_v1 *info = par->targinfo;
52 struct nf_conn *ct = info->ct;
53
54 return xt_ct_target(skb, ct);
55}
56
57static u8 xt_ct_find_proto(const struct xt_tgchk_param *par)
58{
59 if (par->family == NFPROTO_IPV4) {
60 const struct ipt_entry *e = par->entryinfo;
61
62 if (e->ip.invflags & IPT_INV_PROTO)
63 return 0;
64 return e->ip.proto;
65 } else if (par->family == NFPROTO_IPV6) {
66 const struct ip6t_entry *e = par->entryinfo;
67
68 if (e->ipv6.invflags & IP6T_INV_PROTO)
69 return 0;
70 return e->ipv6.proto;
71 } else
72 return 0;
73}
74
75static int
76xt_ct_set_helper(struct nf_conn *ct, const char *helper_name,
77 const struct xt_tgchk_param *par)
78{
79 struct nf_conntrack_helper *helper;
80 struct nf_conn_help *help;
81 u8 proto;
82
83 proto = xt_ct_find_proto(par);
84 if (!proto) {
85 pr_info("You must specify a L4 protocol, and not use "
86 "inversions on it.\n");
87 return -ENOENT;
88 }
89
90 helper = nf_conntrack_helper_try_module_get(helper_name, par->family,
91 proto);
92 if (helper == NULL) {
93 pr_info("No such helper \"%s\"\n", helper_name);
94 return -ENOENT;
95 }
96
97 help = nf_ct_helper_ext_add(ct, helper, GFP_KERNEL);
98 if (help == NULL) {
99 module_put(helper->me);
100 return -ENOMEM;
101 }
102
103 help->helper = helper;
104 return 0;
105}
106
107#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
108static void __xt_ct_tg_timeout_put(struct ctnl_timeout *timeout)
109{
110 typeof(nf_ct_timeout_put_hook) timeout_put;
111
112 timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
113 if (timeout_put)
114 timeout_put(timeout);
115}
116#endif
117
118static int
119xt_ct_set_timeout(struct nf_conn *ct, const struct xt_tgchk_param *par,
120 const char *timeout_name)
121{
122#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
123 typeof(nf_ct_timeout_find_get_hook) timeout_find_get;
124 struct ctnl_timeout *timeout;
125 struct nf_conn_timeout *timeout_ext;
126 struct nf_conntrack_l4proto *l4proto;
127 int ret = 0;
128 u8 proto;
129
130 rcu_read_lock();
131 timeout_find_get = rcu_dereference(nf_ct_timeout_find_get_hook);
132 if (timeout_find_get == NULL) {
133 ret = -ENOENT;
134 pr_info("Timeout policy base is empty\n");
135 goto out;
136 }
137
138 proto = xt_ct_find_proto(par);
139 if (!proto) {
140 ret = -EINVAL;
141 pr_info("You must specify a L4 protocol, and not use "
142 "inversions on it.\n");
143 goto out;
144 }
145
146 timeout = timeout_find_get(par->net, timeout_name);
147 if (timeout == NULL) {
148 ret = -ENOENT;
149 pr_info("No such timeout policy \"%s\"\n", timeout_name);
150 goto out;
151 }
152
153 if (timeout->l3num != par->family) {
154 ret = -EINVAL;
155 pr_info("Timeout policy `%s' can only be used by L3 protocol "
156 "number %d\n", timeout_name, timeout->l3num);
157 goto err_put_timeout;
158 }
159 /* Make sure the timeout policy matches any existing protocol tracker,
160 * otherwise default to generic.
161 */
162 l4proto = __nf_ct_l4proto_find(par->family, proto);
163 if (timeout->l4proto->l4proto != l4proto->l4proto) {
164 ret = -EINVAL;
165 pr_info("Timeout policy `%s' can only be used by L4 protocol "
166 "number %d\n",
167 timeout_name, timeout->l4proto->l4proto);
168 goto err_put_timeout;
169 }
170 timeout_ext = nf_ct_timeout_ext_add(ct, timeout, GFP_ATOMIC);
171 if (timeout_ext == NULL)
172 ret = -ENOMEM;
173
174 rcu_read_unlock();
175 return ret;
176
177err_put_timeout:
178 __xt_ct_tg_timeout_put(timeout);
179out:
180 rcu_read_unlock();
181 return ret;
182#else
183 return -EOPNOTSUPP;
184#endif
185}
186
187static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info)
188{
189 switch (info->flags & (XT_CT_ZONE_DIR_ORIG |
190 XT_CT_ZONE_DIR_REPL)) {
191 case XT_CT_ZONE_DIR_ORIG:
192 return NF_CT_ZONE_DIR_ORIG;
193 case XT_CT_ZONE_DIR_REPL:
194 return NF_CT_ZONE_DIR_REPL;
195 default:
196 return NF_CT_DEFAULT_ZONE_DIR;
197 }
198}
199
200static int xt_ct_tg_check(const struct xt_tgchk_param *par,
201 struct xt_ct_target_info_v1 *info)
202{
203 struct nf_conntrack_zone zone;
204 struct nf_conn *ct;
205 int ret = -EOPNOTSUPP;
206
207 if (info->flags & XT_CT_NOTRACK) {
208 ct = NULL;
209 goto out;
210 }
211
212#ifndef CONFIG_NF_CONNTRACK_ZONES
213 if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG |
214 XT_CT_ZONE_DIR_REPL |
215 XT_CT_ZONE_MARK))
216 goto err1;
217#endif
218
219 ret = nf_ct_netns_get(par->net, par->family);
220 if (ret < 0)
221 goto err1;
222
223 memset(&zone, 0, sizeof(zone));
224 zone.id = info->zone;
225 zone.dir = xt_ct_flags_to_dir(info);
226 if (info->flags & XT_CT_ZONE_MARK)
227 zone.flags |= NF_CT_FLAG_MARK;
228
229 ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL);
230 if (!ct) {
231 ret = -ENOMEM;
232 goto err2;
233 }
234
235 ret = 0;
236 if ((info->ct_events || info->exp_events) &&
237 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
238 GFP_KERNEL)) {
239 ret = -EINVAL;
240 goto err3;
241 }
242
243 if (info->helper[0]) {
244 ret = xt_ct_set_helper(ct, info->helper, par);
245 if (ret < 0)
246 goto err3;
247 }
248
249 if (info->timeout[0]) {
250 ret = xt_ct_set_timeout(ct, par, info->timeout);
251 if (ret < 0)
252 goto err3;
253 }
254 __set_bit(IPS_CONFIRMED_BIT, &ct->status);
255 nf_conntrack_get(&ct->ct_general);
256out:
257 info->ct = ct;
258 return 0;
259
260err3:
261 nf_ct_tmpl_free(ct);
262err2:
263 nf_ct_netns_put(par->net, par->family);
264err1:
265 return ret;
266}
267
268static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par)
269{
270 struct xt_ct_target_info *info = par->targinfo;
271 struct xt_ct_target_info_v1 info_v1 = {
272 .flags = info->flags,
273 .zone = info->zone,
274 .ct_events = info->ct_events,
275 .exp_events = info->exp_events,
276 };
277 int ret;
278
279 if (info->flags & ~XT_CT_NOTRACK)
280 return -EINVAL;
281
282 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
283
284 ret = xt_ct_tg_check(par, &info_v1);
285 if (ret < 0)
286 return ret;
287
288 info->ct = info_v1.ct;
289
290 return ret;
291}
292
293static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
294{
295 struct xt_ct_target_info_v1 *info = par->targinfo;
296
297 if (info->flags & ~XT_CT_NOTRACK)
298 return -EINVAL;
299
300 return xt_ct_tg_check(par, par->targinfo);
301}
302
303static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par)
304{
305 struct xt_ct_target_info_v1 *info = par->targinfo;
306
307 if (info->flags & ~XT_CT_MASK)
308 return -EINVAL;
309
310 return xt_ct_tg_check(par, par->targinfo);
311}
312
313static void xt_ct_destroy_timeout(struct nf_conn *ct)
314{
315#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
316 struct nf_conn_timeout *timeout_ext;
317 typeof(nf_ct_timeout_put_hook) timeout_put;
318
319 rcu_read_lock();
320 timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
321
322 if (timeout_put) {
323 timeout_ext = nf_ct_timeout_find(ct);
324 if (timeout_ext) {
325 timeout_put(timeout_ext->timeout);
326 RCU_INIT_POINTER(timeout_ext->timeout, NULL);
327 }
328 }
329 rcu_read_unlock();
330#endif
331}
332
333static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par,
334 struct xt_ct_target_info_v1 *info)
335{
336 struct nf_conn *ct = info->ct;
337 struct nf_conn_help *help;
338
339 if (ct && !nf_ct_is_untracked(ct)) {
340 help = nfct_help(ct);
341 if (help)
342 module_put(help->helper->me);
343
344 nf_ct_netns_put(par->net, par->family);
345
346 xt_ct_destroy_timeout(ct);
347 nf_ct_put(info->ct);
348 }
349}
350
351static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par)
352{
353 struct xt_ct_target_info *info = par->targinfo;
354 struct xt_ct_target_info_v1 info_v1 = {
355 .flags = info->flags,
356 .zone = info->zone,
357 .ct_events = info->ct_events,
358 .exp_events = info->exp_events,
359 .ct = info->ct,
360 };
361 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
362
363 xt_ct_tg_destroy(par, &info_v1);
364}
365
366static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par)
367{
368 xt_ct_tg_destroy(par, par->targinfo);
369}
370
371static struct xt_target xt_ct_tg_reg[] __read_mostly = {
372 {
373 .name = "CT",
374 .family = NFPROTO_UNSPEC,
375 .targetsize = sizeof(struct xt_ct_target_info),
376 .checkentry = xt_ct_tg_check_v0,
377 .destroy = xt_ct_tg_destroy_v0,
378 .target = xt_ct_target_v0,
379 .table = "raw",
380 .me = THIS_MODULE,
381 },
382 {
383 .name = "CT",
384 .family = NFPROTO_UNSPEC,
385 .revision = 1,
386 .targetsize = sizeof(struct xt_ct_target_info_v1),
387 .checkentry = xt_ct_tg_check_v1,
388 .destroy = xt_ct_tg_destroy_v1,
389 .target = xt_ct_target_v1,
390 .table = "raw",
391 .me = THIS_MODULE,
392 },
393 {
394 .name = "CT",
395 .family = NFPROTO_UNSPEC,
396 .revision = 2,
397 .targetsize = sizeof(struct xt_ct_target_info_v1),
398 .checkentry = xt_ct_tg_check_v2,
399 .destroy = xt_ct_tg_destroy_v1,
400 .target = xt_ct_target_v1,
401 .table = "raw",
402 .me = THIS_MODULE,
403 },
404};
405
406static unsigned int
407notrack_tg(struct sk_buff *skb, const struct xt_action_param *par)
408{
409 /* Previously seen (loopback)? Ignore. */
410 if (skb->nfct != NULL)
411 return XT_CONTINUE;
412
413 skb->nfct = &nf_ct_untracked_get()->ct_general;
414 skb->nfctinfo = IP_CT_NEW;
415 nf_conntrack_get(skb->nfct);
416
417 return XT_CONTINUE;
418}
419
420static int notrack_chk(const struct xt_tgchk_param *par)
421{
422 if (!par->net->xt.notrack_deprecated_warning) {
423 pr_info("netfilter: NOTRACK target is deprecated, "
424 "use CT instead or upgrade iptables\n");
425 par->net->xt.notrack_deprecated_warning = true;
426 }
427 return 0;
428}
429
430static struct xt_target notrack_tg_reg __read_mostly = {
431 .name = "NOTRACK",
432 .revision = 0,
433 .family = NFPROTO_UNSPEC,
434 .checkentry = notrack_chk,
435 .target = notrack_tg,
436 .table = "raw",
437 .me = THIS_MODULE,
438};
439
440static int __init xt_ct_tg_init(void)
441{
442 int ret;
443
444 ret = xt_register_target(¬rack_tg_reg);
445 if (ret < 0)
446 return ret;
447
448 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
449 if (ret < 0) {
450 xt_unregister_target(¬rack_tg_reg);
451 return ret;
452 }
453 return 0;
454}
455
456static void __exit xt_ct_tg_exit(void)
457{
458 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
459 xt_unregister_target(¬rack_tg_reg);
460}
461
462module_init(xt_ct_tg_init);
463module_exit(xt_ct_tg_exit);
464
465MODULE_LICENSE("GPL");
466MODULE_DESCRIPTION("Xtables: connection tracking target");
467MODULE_ALIAS("ipt_CT");
468MODULE_ALIAS("ip6t_CT");
469MODULE_ALIAS("ipt_NOTRACK");
470MODULE_ALIAS("ip6t_NOTRACK");
1/*
2 * Copyright (c) 2010 Patrick McHardy <kaber@trash.net>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9#include <linux/module.h>
10#include <linux/gfp.h>
11#include <linux/skbuff.h>
12#include <linux/netfilter_ipv4/ip_tables.h>
13#include <linux/netfilter_ipv6/ip6_tables.h>
14#include <linux/netfilter/x_tables.h>
15#include <linux/netfilter/xt_CT.h>
16#include <net/netfilter/nf_conntrack.h>
17#include <net/netfilter/nf_conntrack_helper.h>
18#include <net/netfilter/nf_conntrack_ecache.h>
19#include <net/netfilter/nf_conntrack_zones.h>
20
21static unsigned int xt_ct_target(struct sk_buff *skb,
22 const struct xt_action_param *par)
23{
24 const struct xt_ct_target_info *info = par->targinfo;
25 struct nf_conn *ct = info->ct;
26
27 /* Previously seen (loopback)? Ignore. */
28 if (skb->nfct != NULL)
29 return XT_CONTINUE;
30
31 atomic_inc(&ct->ct_general.use);
32 skb->nfct = &ct->ct_general;
33 skb->nfctinfo = IP_CT_NEW;
34
35 return XT_CONTINUE;
36}
37
38static u8 xt_ct_find_proto(const struct xt_tgchk_param *par)
39{
40 if (par->family == NFPROTO_IPV4) {
41 const struct ipt_entry *e = par->entryinfo;
42
43 if (e->ip.invflags & IPT_INV_PROTO)
44 return 0;
45 return e->ip.proto;
46 } else if (par->family == NFPROTO_IPV6) {
47 const struct ip6t_entry *e = par->entryinfo;
48
49 if (e->ipv6.invflags & IP6T_INV_PROTO)
50 return 0;
51 return e->ipv6.proto;
52 } else
53 return 0;
54}
55
56static int xt_ct_tg_check(const struct xt_tgchk_param *par)
57{
58 struct xt_ct_target_info *info = par->targinfo;
59 struct nf_conntrack_tuple t;
60 struct nf_conn_help *help;
61 struct nf_conn *ct;
62 int ret = 0;
63 u8 proto;
64
65 if (info->flags & ~XT_CT_NOTRACK)
66 return -EINVAL;
67
68 if (info->flags & XT_CT_NOTRACK) {
69 ct = nf_ct_untracked_get();
70 atomic_inc(&ct->ct_general.use);
71 goto out;
72 }
73
74#ifndef CONFIG_NF_CONNTRACK_ZONES
75 if (info->zone)
76 goto err1;
77#endif
78
79 ret = nf_ct_l3proto_try_module_get(par->family);
80 if (ret < 0)
81 goto err1;
82
83 memset(&t, 0, sizeof(t));
84 ct = nf_conntrack_alloc(par->net, info->zone, &t, &t, GFP_KERNEL);
85 ret = PTR_ERR(ct);
86 if (IS_ERR(ct))
87 goto err2;
88
89 ret = 0;
90 if ((info->ct_events || info->exp_events) &&
91 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
92 GFP_KERNEL))
93 goto err3;
94
95 if (info->helper[0]) {
96 ret = -ENOENT;
97 proto = xt_ct_find_proto(par);
98 if (!proto) {
99 pr_info("You must specify a L4 protocol, "
100 "and not use inversions on it.\n");
101 goto err3;
102 }
103
104 ret = -ENOMEM;
105 help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
106 if (help == NULL)
107 goto err3;
108
109 ret = -ENOENT;
110 help->helper = nf_conntrack_helper_try_module_get(info->helper,
111 par->family,
112 proto);
113 if (help->helper == NULL) {
114 pr_info("No such helper \"%s\"\n", info->helper);
115 goto err3;
116 }
117 }
118
119 __set_bit(IPS_TEMPLATE_BIT, &ct->status);
120 __set_bit(IPS_CONFIRMED_BIT, &ct->status);
121out:
122 info->ct = ct;
123 return 0;
124
125err3:
126 nf_conntrack_free(ct);
127err2:
128 nf_ct_l3proto_module_put(par->family);
129err1:
130 return ret;
131}
132
133static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par)
134{
135 struct xt_ct_target_info *info = par->targinfo;
136 struct nf_conn *ct = info->ct;
137 struct nf_conn_help *help;
138
139 if (!nf_ct_is_untracked(ct)) {
140 help = nfct_help(ct);
141 if (help)
142 module_put(help->helper->me);
143
144 nf_ct_l3proto_module_put(par->family);
145 }
146 nf_ct_put(info->ct);
147}
148
149static struct xt_target xt_ct_tg __read_mostly = {
150 .name = "CT",
151 .family = NFPROTO_UNSPEC,
152 .targetsize = sizeof(struct xt_ct_target_info),
153 .checkentry = xt_ct_tg_check,
154 .destroy = xt_ct_tg_destroy,
155 .target = xt_ct_target,
156 .table = "raw",
157 .me = THIS_MODULE,
158};
159
160static int __init xt_ct_tg_init(void)
161{
162 return xt_register_target(&xt_ct_tg);
163}
164
165static void __exit xt_ct_tg_exit(void)
166{
167 xt_unregister_target(&xt_ct_tg);
168}
169
170module_init(xt_ct_tg_init);
171module_exit(xt_ct_tg_exit);
172
173MODULE_LICENSE("GPL");
174MODULE_DESCRIPTION("Xtables: connection tracking target");
175MODULE_ALIAS("ipt_CT");
176MODULE_ALIAS("ip6t_CT");