netfilter: nf_conntrack: add direction support for zones
[deliverable/linux.git] / net / netfilter / xt_CT.c
CommitLineData
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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 */
a7fed762 8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
84f3bb9a 9#include <linux/module.h>
5a0e3ad6 10#include <linux/gfp.h>
84f3bb9a 11#include <linux/skbuff.h>
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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>
eeb4cb95 17#include <net/netfilter/nf_conntrack_l4proto.h>
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18#include <net/netfilter/nf_conntrack_helper.h>
19#include <net/netfilter/nf_conntrack_ecache.h>
24de58f4 20#include <net/netfilter/nf_conntrack_timeout.h>
5d0aa2cc 21#include <net/netfilter/nf_conntrack_zones.h>
84f3bb9a 22
d52ed437 23static inline int xt_ct_target(struct sk_buff *skb, struct nf_conn *ct)
84f3bb9a 24{
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25 /* Previously seen (loopback)? Ignore. */
26 if (skb->nfct != NULL)
27 return XT_CONTINUE;
28
27e7190e
ED
29 /* special case the untracked ct : we want the percpu object */
30 if (!ct)
31 ct = nf_ct_untracked_get();
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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
d52ed437 39static unsigned int xt_ct_target_v0(struct sk_buff *skb,
24de58f4
PNA
40 const struct xt_action_param *par)
41{
d52ed437 42 const struct xt_ct_target_info *info = par->targinfo;
24de58f4
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43 struct nf_conn *ct = info->ct;
44
d52ed437
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45 return xt_ct_target(skb, ct);
46}
24de58f4 47
d52ed437
PNA
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;
24de58f4 53
d52ed437 54 return xt_ct_target(skb, ct);
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55}
56
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57static u8 xt_ct_find_proto(const struct xt_tgchk_param *par)
58{
076f7839 59 if (par->family == NFPROTO_IPV4) {
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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;
076f7839 65 } else if (par->family == NFPROTO_IPV6) {
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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
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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
ee14186f
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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
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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;
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126 struct nf_conntrack_l4proto *l4proto;
127 int ret = 0;
0153d5a8 128 u8 proto;
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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
0153d5a8
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138 proto = xt_ct_find_proto(par);
139 if (!proto) {
236df005 140 ret = -EINVAL;
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141 pr_info("You must specify a L4 protocol, and not use "
142 "inversions on it.\n");
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143 goto out;
144 }
145
146 timeout = timeout_find_get(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 */
0153d5a8 162 l4proto = __nf_ct_l4proto_find(par->family, proto);
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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
174err_put_timeout:
175 __xt_ct_tg_timeout_put(timeout);
176out:
177 rcu_read_unlock();
178 return ret;
179#else
180 return -EOPNOTSUPP;
181#endif
182}
183
deedb590
DB
184static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info)
185{
186 switch (info->flags & (XT_CT_ZONE_DIR_ORIG |
187 XT_CT_ZONE_DIR_REPL)) {
188 case XT_CT_ZONE_DIR_ORIG:
189 return NF_CT_ZONE_DIR_ORIG;
190 case XT_CT_ZONE_DIR_REPL:
191 return NF_CT_ZONE_DIR_REPL;
192 default:
193 return NF_CT_DEFAULT_ZONE_DIR;
194 }
195}
196
d52ed437
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197static int xt_ct_tg_check(const struct xt_tgchk_param *par,
198 struct xt_ct_target_info_v1 *info)
24de58f4 199{
308ac914 200 struct nf_conntrack_zone zone;
24de58f4 201 struct nf_conn *ct;
4610476d 202 int ret = -EOPNOTSUPP;
236df005 203
24de58f4 204 if (info->flags & XT_CT_NOTRACK) {
27e7190e 205 ct = NULL;
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206 goto out;
207 }
208
209#ifndef CONFIG_NF_CONNTRACK_ZONES
deedb590
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210 if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG |
211 XT_CT_ZONE_DIR_REPL))
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212 goto err1;
213#endif
214
215 ret = nf_ct_l3proto_try_module_get(par->family);
216 if (ret < 0)
217 goto err1;
218
308ac914
DB
219 memset(&zone, 0, sizeof(zone));
220 zone.id = info->zone;
deedb590 221 zone.dir = xt_ct_flags_to_dir(info);
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222
223 ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL);
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224 ret = PTR_ERR(ct);
225 if (IS_ERR(ct))
226 goto err2;
227
228 ret = 0;
229 if ((info->ct_events || info->exp_events) &&
230 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
14abfa16
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231 GFP_KERNEL)) {
232 ret = -EINVAL;
24de58f4 233 goto err3;
14abfa16 234 }
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235
236 if (info->helper[0]) {
236df005
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237 ret = xt_ct_set_helper(ct, info->helper, par);
238 if (ret < 0)
1afc5679 239 goto err3;
24de58f4
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240 }
241
6cf51852 242 if (info->timeout[0]) {
236df005
PNA
243 ret = xt_ct_set_timeout(ct, par, info->timeout);
244 if (ret < 0)
245 goto err3;
24de58f4 246 }
0838aa7f
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247 __set_bit(IPS_CONFIRMED_BIT, &ct->status);
248 nf_conntrack_get(&ct->ct_general);
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249out:
250 info->ct = ct;
251 return 0;
252
253err3:
254 nf_conntrack_free(ct);
255err2:
256 nf_ct_l3proto_module_put(par->family);
257err1:
258 return ret;
259}
260
d52ed437 261static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par)
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262{
263 struct xt_ct_target_info *info = par->targinfo;
d52ed437
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264 struct xt_ct_target_info_v1 info_v1 = {
265 .flags = info->flags,
266 .zone = info->zone,
267 .ct_events = info->ct_events,
268 .exp_events = info->exp_events,
269 };
270 int ret;
84f3bb9a 271
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272 if (info->flags & ~XT_CT_NOTRACK)
273 return -EINVAL;
274
d52ed437 275 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
84f3bb9a 276
d52ed437
PNA
277 ret = xt_ct_tg_check(par, &info_v1);
278 if (ret < 0)
279 return ret;
280
281 info->ct = info_v1.ct;
282
283 return ret;
284}
285
286static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
287{
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288 struct xt_ct_target_info_v1 *info = par->targinfo;
289
290 if (info->flags & ~XT_CT_NOTRACK)
291 return -EINVAL;
292
293 return xt_ct_tg_check(par, par->targinfo);
294}
295
296static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par)
297{
298 struct xt_ct_target_info_v1 *info = par->targinfo;
299
300 if (info->flags & ~XT_CT_MASK)
301 return -EINVAL;
302
d52ed437 303 return xt_ct_tg_check(par, par->targinfo);
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304}
305
236df005 306static void xt_ct_destroy_timeout(struct nf_conn *ct)
24de58f4 307{
24de58f4
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308#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
309 struct nf_conn_timeout *timeout_ext;
310 typeof(nf_ct_timeout_put_hook) timeout_put;
236df005
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311
312 rcu_read_lock();
313 timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
314
315 if (timeout_put) {
316 timeout_ext = nf_ct_timeout_find(ct);
317 if (timeout_ext)
318 timeout_put(timeout_ext->timeout);
319 }
320 rcu_read_unlock();
24de58f4 321#endif
236df005
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322}
323
d52ed437
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324static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par,
325 struct xt_ct_target_info_v1 *info)
236df005 326{
236df005
PNA
327 struct nf_conn *ct = info->ct;
328 struct nf_conn_help *help;
329
27e7190e 330 if (ct && !nf_ct_is_untracked(ct)) {
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PNA
331 help = nfct_help(ct);
332 if (help)
333 module_put(help->helper->me);
334
335 nf_ct_l3proto_module_put(par->family);
336
236df005 337 xt_ct_destroy_timeout(ct);
27e7190e 338 nf_ct_put(info->ct);
24de58f4 339 }
d52ed437
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340}
341
342static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par)
343{
344 struct xt_ct_target_info *info = par->targinfo;
345 struct xt_ct_target_info_v1 info_v1 = {
346 .flags = info->flags,
347 .zone = info->zone,
348 .ct_events = info->ct_events,
349 .exp_events = info->exp_events,
350 .ct = info->ct,
351 };
352 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
353
354 xt_ct_tg_destroy(par, &info_v1);
355}
356
357static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par)
358{
359 xt_ct_tg_destroy(par, par->targinfo);
24de58f4
PNA
360}
361
362static struct xt_target xt_ct_tg_reg[] __read_mostly = {
363 {
364 .name = "CT",
365 .family = NFPROTO_UNSPEC,
366 .targetsize = sizeof(struct xt_ct_target_info),
367 .checkentry = xt_ct_tg_check_v0,
368 .destroy = xt_ct_tg_destroy_v0,
369 .target = xt_ct_target_v0,
370 .table = "raw",
371 .me = THIS_MODULE,
372 },
373 {
374 .name = "CT",
375 .family = NFPROTO_UNSPEC,
376 .revision = 1,
377 .targetsize = sizeof(struct xt_ct_target_info_v1),
378 .checkentry = xt_ct_tg_check_v1,
379 .destroy = xt_ct_tg_destroy_v1,
380 .target = xt_ct_target_v1,
381 .table = "raw",
382 .me = THIS_MODULE,
383 },
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PNA
384 {
385 .name = "CT",
386 .family = NFPROTO_UNSPEC,
387 .revision = 2,
388 .targetsize = sizeof(struct xt_ct_target_info_v1),
389 .checkentry = xt_ct_tg_check_v2,
390 .destroy = xt_ct_tg_destroy_v1,
391 .target = xt_ct_target_v1,
392 .table = "raw",
393 .me = THIS_MODULE,
394 },
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395};
396
10db9069
PNA
397static unsigned int
398notrack_tg(struct sk_buff *skb, const struct xt_action_param *par)
399{
400 /* Previously seen (loopback)? Ignore. */
401 if (skb->nfct != NULL)
402 return XT_CONTINUE;
403
404 skb->nfct = &nf_ct_untracked_get()->ct_general;
405 skb->nfctinfo = IP_CT_NEW;
406 nf_conntrack_get(skb->nfct);
407
408 return XT_CONTINUE;
409}
410
411static int notrack_chk(const struct xt_tgchk_param *par)
412{
413 if (!par->net->xt.notrack_deprecated_warning) {
414 pr_info("netfilter: NOTRACK target is deprecated, "
415 "use CT instead or upgrade iptables\n");
416 par->net->xt.notrack_deprecated_warning = true;
417 }
418 return 0;
419}
420
421static struct xt_target notrack_tg_reg __read_mostly = {
422 .name = "NOTRACK",
423 .revision = 0,
424 .family = NFPROTO_UNSPEC,
425 .checkentry = notrack_chk,
426 .target = notrack_tg,
427 .table = "raw",
428 .me = THIS_MODULE,
429};
430
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431static int __init xt_ct_tg_init(void)
432{
10db9069
PNA
433 int ret;
434
435 ret = xt_register_target(&notrack_tg_reg);
436 if (ret < 0)
437 return ret;
438
439 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
440 if (ret < 0) {
441 xt_unregister_target(&notrack_tg_reg);
442 return ret;
443 }
444 return 0;
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445}
446
447static void __exit xt_ct_tg_exit(void)
448{
24de58f4 449 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
10db9069 450 xt_unregister_target(&notrack_tg_reg);
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451}
452
453module_init(xt_ct_tg_init);
454module_exit(xt_ct_tg_exit);
455
456MODULE_LICENSE("GPL");
457MODULE_DESCRIPTION("Xtables: connection tracking target");
458MODULE_ALIAS("ipt_CT");
459MODULE_ALIAS("ip6t_CT");
10db9069
PNA
460MODULE_ALIAS("ipt_NOTRACK");
461MODULE_ALIAS("ip6t_NOTRACK");
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