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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
26 if (skb->_nfct != 0)
27 return XT_CONTINUE;
28
29 if (ct) {
30 atomic_inc(&ct->ct_general.use);
31 nf_ct_set(skb, ct, IP_CT_NEW);
32 } else {
33 nf_ct_set(skb, ct, IP_CT_UNTRACKED);
34 }
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 nf_conntrack_helper_put(helper);
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 const struct nf_conntrack_l4proto *l4proto;
125 struct ctnl_timeout *timeout;
126 struct nf_conn_timeout *timeout_ext;
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
160
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) {
172 ret = -ENOMEM;
173 goto err_put_timeout;
174 }
175
176 rcu_read_unlock();
177 return ret;
178
179err_put_timeout:
180 __xt_ct_tg_timeout_put(timeout);
181out:
182 rcu_read_unlock();
183 return ret;
184#else
185 return -EOPNOTSUPP;
186#endif
187}
188
189static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info)
190{
191 switch (info->flags & (XT_CT_ZONE_DIR_ORIG |
192 XT_CT_ZONE_DIR_REPL)) {
193 case XT_CT_ZONE_DIR_ORIG:
194 return NF_CT_ZONE_DIR_ORIG;
195 case XT_CT_ZONE_DIR_REPL:
196 return NF_CT_ZONE_DIR_REPL;
197 default:
198 return NF_CT_DEFAULT_ZONE_DIR;
199 }
200}
201
202static int xt_ct_tg_check(const struct xt_tgchk_param *par,
203 struct xt_ct_target_info_v1 *info)
204{
205 struct nf_conntrack_zone zone;
206 struct nf_conn_help *help;
207 struct nf_conn *ct;
208 int ret = -EOPNOTSUPP;
209
210 if (info->flags & XT_CT_NOTRACK) {
211 ct = NULL;
212 goto out;
213 }
214
215#ifndef CONFIG_NF_CONNTRACK_ZONES
216 if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG |
217 XT_CT_ZONE_DIR_REPL |
218 XT_CT_ZONE_MARK))
219 goto err1;
220#endif
221
222 ret = nf_ct_netns_get(par->net, par->family);
223 if (ret < 0)
224 goto err1;
225
226 memset(&zone, 0, sizeof(zone));
227 zone.id = info->zone;
228 zone.dir = xt_ct_flags_to_dir(info);
229 if (info->flags & XT_CT_ZONE_MARK)
230 zone.flags |= NF_CT_FLAG_MARK;
231
232 ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL);
233 if (!ct) {
234 ret = -ENOMEM;
235 goto err2;
236 }
237
238 ret = 0;
239 if ((info->ct_events || info->exp_events) &&
240 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
241 GFP_KERNEL)) {
242 ret = -EINVAL;
243 goto err3;
244 }
245
246 if (info->helper[0]) {
247 ret = xt_ct_set_helper(ct, info->helper, par);
248 if (ret < 0)
249 goto err3;
250 }
251
252 if (info->timeout[0]) {
253 ret = xt_ct_set_timeout(ct, par, info->timeout);
254 if (ret < 0)
255 goto err4;
256 }
257 __set_bit(IPS_CONFIRMED_BIT, &ct->status);
258 nf_conntrack_get(&ct->ct_general);
259out:
260 info->ct = ct;
261 return 0;
262
263err4:
264 help = nfct_help(ct);
265 if (help)
266 nf_conntrack_helper_put(help->helper);
267err3:
268 nf_ct_tmpl_free(ct);
269err2:
270 nf_ct_netns_put(par->net, par->family);
271err1:
272 return ret;
273}
274
275static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par)
276{
277 struct xt_ct_target_info *info = par->targinfo;
278 struct xt_ct_target_info_v1 info_v1 = {
279 .flags = info->flags,
280 .zone = info->zone,
281 .ct_events = info->ct_events,
282 .exp_events = info->exp_events,
283 };
284 int ret;
285
286 if (info->flags & ~XT_CT_NOTRACK)
287 return -EINVAL;
288
289 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
290
291 ret = xt_ct_tg_check(par, &info_v1);
292 if (ret < 0)
293 return ret;
294
295 info->ct = info_v1.ct;
296
297 return ret;
298}
299
300static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
301{
302 struct xt_ct_target_info_v1 *info = par->targinfo;
303
304 if (info->flags & ~XT_CT_NOTRACK)
305 return -EINVAL;
306
307 return xt_ct_tg_check(par, par->targinfo);
308}
309
310static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par)
311{
312 struct xt_ct_target_info_v1 *info = par->targinfo;
313
314 if (info->flags & ~XT_CT_MASK)
315 return -EINVAL;
316
317 return xt_ct_tg_check(par, par->targinfo);
318}
319
320static void xt_ct_destroy_timeout(struct nf_conn *ct)
321{
322#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
323 struct nf_conn_timeout *timeout_ext;
324 typeof(nf_ct_timeout_put_hook) timeout_put;
325
326 rcu_read_lock();
327 timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
328
329 if (timeout_put) {
330 timeout_ext = nf_ct_timeout_find(ct);
331 if (timeout_ext) {
332 timeout_put(timeout_ext->timeout);
333 RCU_INIT_POINTER(timeout_ext->timeout, NULL);
334 }
335 }
336 rcu_read_unlock();
337#endif
338}
339
340static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par,
341 struct xt_ct_target_info_v1 *info)
342{
343 struct nf_conn *ct = info->ct;
344 struct nf_conn_help *help;
345
346 if (ct) {
347 help = nfct_help(ct);
348 if (help)
349 nf_conntrack_helper_put(help->helper);
350
351 nf_ct_netns_put(par->net, par->family);
352
353 xt_ct_destroy_timeout(ct);
354 nf_ct_put(info->ct);
355 }
356}
357
358static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par)
359{
360 struct xt_ct_target_info *info = par->targinfo;
361 struct xt_ct_target_info_v1 info_v1 = {
362 .flags = info->flags,
363 .zone = info->zone,
364 .ct_events = info->ct_events,
365 .exp_events = info->exp_events,
366 .ct = info->ct,
367 };
368 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
369
370 xt_ct_tg_destroy(par, &info_v1);
371}
372
373static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par)
374{
375 xt_ct_tg_destroy(par, par->targinfo);
376}
377
378static struct xt_target xt_ct_tg_reg[] __read_mostly = {
379 {
380 .name = "CT",
381 .family = NFPROTO_UNSPEC,
382 .targetsize = sizeof(struct xt_ct_target_info),
383 .usersize = offsetof(struct xt_ct_target_info, ct),
384 .checkentry = xt_ct_tg_check_v0,
385 .destroy = xt_ct_tg_destroy_v0,
386 .target = xt_ct_target_v0,
387 .table = "raw",
388 .me = THIS_MODULE,
389 },
390 {
391 .name = "CT",
392 .family = NFPROTO_UNSPEC,
393 .revision = 1,
394 .targetsize = sizeof(struct xt_ct_target_info_v1),
395 .usersize = offsetof(struct xt_ct_target_info, ct),
396 .checkentry = xt_ct_tg_check_v1,
397 .destroy = xt_ct_tg_destroy_v1,
398 .target = xt_ct_target_v1,
399 .table = "raw",
400 .me = THIS_MODULE,
401 },
402 {
403 .name = "CT",
404 .family = NFPROTO_UNSPEC,
405 .revision = 2,
406 .targetsize = sizeof(struct xt_ct_target_info_v1),
407 .usersize = offsetof(struct xt_ct_target_info, ct),
408 .checkentry = xt_ct_tg_check_v2,
409 .destroy = xt_ct_tg_destroy_v1,
410 .target = xt_ct_target_v1,
411 .table = "raw",
412 .me = THIS_MODULE,
413 },
414};
415
416static unsigned int
417notrack_tg(struct sk_buff *skb, const struct xt_action_param *par)
418{
419
420 if (skb->_nfct != 0)
421 return XT_CONTINUE;
422
423 nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
424
425 return XT_CONTINUE;
426}
427
428static int notrack_chk(const struct xt_tgchk_param *par)
429{
430 if (!par->net->xt.notrack_deprecated_warning) {
431 pr_info("netfilter: NOTRACK target is deprecated, "
432 "use CT instead or upgrade iptables\n");
433 par->net->xt.notrack_deprecated_warning = true;
434 }
435 return 0;
436}
437
438static struct xt_target notrack_tg_reg __read_mostly = {
439 .name = "NOTRACK",
440 .revision = 0,
441 .family = NFPROTO_UNSPEC,
442 .checkentry = notrack_chk,
443 .target = notrack_tg,
444 .table = "raw",
445 .me = THIS_MODULE,
446};
447
448static int __init xt_ct_tg_init(void)
449{
450 int ret;
451
452 ret = xt_register_target(¬rack_tg_reg);
453 if (ret < 0)
454 return ret;
455
456 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
457 if (ret < 0) {
458 xt_unregister_target(¬rack_tg_reg);
459 return ret;
460 }
461 return 0;
462}
463
464static void __exit xt_ct_tg_exit(void)
465{
466 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
467 xt_unregister_target(¬rack_tg_reg);
468}
469
470module_init(xt_ct_tg_init);
471module_exit(xt_ct_tg_exit);
472
473MODULE_LICENSE("GPL");
474MODULE_DESCRIPTION("Xtables: connection tracking target");
475MODULE_ALIAS("ipt_CT");
476MODULE_ALIAS("ip6t_CT");
477MODULE_ALIAS("ipt_NOTRACK");
478MODULE_ALIAS("ip6t_NOTRACK");
479
