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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 != NULL)
27 return XT_CONTINUE;
28
29
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(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 == 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
184static int xt_ct_tg_check(const struct xt_tgchk_param *par,
185 struct xt_ct_target_info_v1 *info)
186{
187 struct nf_conntrack_tuple t;
188 struct nf_conn *ct;
189 int ret = -EOPNOTSUPP;
190
191 if (info->flags & XT_CT_NOTRACK) {
192 ct = NULL;
193 goto out;
194 }
195
196#ifndef CONFIG_NF_CONNTRACK_ZONES
197 if (info->zone)
198 goto err1;
199#endif
200
201 ret = nf_ct_l3proto_try_module_get(par->family);
202 if (ret < 0)
203 goto err1;
204
205 memset(&t, 0, sizeof(t));
206 ct = nf_conntrack_alloc(par->net, info->zone, &t, &t, GFP_KERNEL);
207 ret = PTR_ERR(ct);
208 if (IS_ERR(ct))
209 goto err2;
210
211 ret = 0;
212 if ((info->ct_events || info->exp_events) &&
213 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
214 GFP_KERNEL)) {
215 ret = -EINVAL;
216 goto err3;
217 }
218
219 if (info->helper[0]) {
220 ret = xt_ct_set_helper(ct, info->helper, par);
221 if (ret < 0)
222 goto err3;
223 }
224
225 if (info->timeout[0]) {
226 ret = xt_ct_set_timeout(ct, par, info->timeout);
227 if (ret < 0)
228 goto err3;
229 }
230
231 nf_conntrack_tmpl_insert(par->net, ct);
232out:
233 info->ct = ct;
234 return 0;
235
236err3:
237 nf_conntrack_free(ct);
238err2:
239 nf_ct_l3proto_module_put(par->family);
240err1:
241 return ret;
242}
243
244static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par)
245{
246 struct xt_ct_target_info *info = par->targinfo;
247 struct xt_ct_target_info_v1 info_v1 = {
248 .flags = info->flags,
249 .zone = info->zone,
250 .ct_events = info->ct_events,
251 .exp_events = info->exp_events,
252 };
253 int ret;
254
255 if (info->flags & ~XT_CT_NOTRACK)
256 return -EINVAL;
257
258 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
259
260 ret = xt_ct_tg_check(par, &info_v1);
261 if (ret < 0)
262 return ret;
263
264 info->ct = info_v1.ct;
265
266 return ret;
267}
268
269static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
270{
271 struct xt_ct_target_info_v1 *info = par->targinfo;
272
273 if (info->flags & ~XT_CT_NOTRACK)
274 return -EINVAL;
275
276 return xt_ct_tg_check(par, par->targinfo);
277}
278
279static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par)
280{
281 struct xt_ct_target_info_v1 *info = par->targinfo;
282
283 if (info->flags & ~XT_CT_MASK)
284 return -EINVAL;
285
286 return xt_ct_tg_check(par, par->targinfo);
287}
288
289static void xt_ct_destroy_timeout(struct nf_conn *ct)
290{
291#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
292 struct nf_conn_timeout *timeout_ext;
293 typeof(nf_ct_timeout_put_hook) timeout_put;
294
295 rcu_read_lock();
296 timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
297
298 if (timeout_put) {
299 timeout_ext = nf_ct_timeout_find(ct);
300 if (timeout_ext)
301 timeout_put(timeout_ext->timeout);
302 }
303 rcu_read_unlock();
304#endif
305}
306
307static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par,
308 struct xt_ct_target_info_v1 *info)
309{
310 struct nf_conn *ct = info->ct;
311 struct nf_conn_help *help;
312
313 if (ct && !nf_ct_is_untracked(ct)) {
314 help = nfct_help(ct);
315 if (help)
316 module_put(help->helper->me);
317
318 nf_ct_l3proto_module_put(par->family);
319
320 xt_ct_destroy_timeout(ct);
321 nf_ct_put(info->ct);
322 }
323}
324
325static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par)
326{
327 struct xt_ct_target_info *info = par->targinfo;
328 struct xt_ct_target_info_v1 info_v1 = {
329 .flags = info->flags,
330 .zone = info->zone,
331 .ct_events = info->ct_events,
332 .exp_events = info->exp_events,
333 .ct = info->ct,
334 };
335 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
336
337 xt_ct_tg_destroy(par, &info_v1);
338}
339
340static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par)
341{
342 xt_ct_tg_destroy(par, par->targinfo);
343}
344
345static struct xt_target xt_ct_tg_reg[] __read_mostly = {
346 {
347 .name = "CT",
348 .family = NFPROTO_UNSPEC,
349 .targetsize = sizeof(struct xt_ct_target_info),
350 .checkentry = xt_ct_tg_check_v0,
351 .destroy = xt_ct_tg_destroy_v0,
352 .target = xt_ct_target_v0,
353 .table = "raw",
354 .me = THIS_MODULE,
355 },
356 {
357 .name = "CT",
358 .family = NFPROTO_UNSPEC,
359 .revision = 1,
360 .targetsize = sizeof(struct xt_ct_target_info_v1),
361 .checkentry = xt_ct_tg_check_v1,
362 .destroy = xt_ct_tg_destroy_v1,
363 .target = xt_ct_target_v1,
364 .table = "raw",
365 .me = THIS_MODULE,
366 },
367 {
368 .name = "CT",
369 .family = NFPROTO_UNSPEC,
370 .revision = 2,
371 .targetsize = sizeof(struct xt_ct_target_info_v1),
372 .checkentry = xt_ct_tg_check_v2,
373 .destroy = xt_ct_tg_destroy_v1,
374 .target = xt_ct_target_v1,
375 .table = "raw",
376 .me = THIS_MODULE,
377 },
378};
379
380static unsigned int
381notrack_tg(struct sk_buff *skb, const struct xt_action_param *par)
382{
383
384 if (skb->nfct != NULL)
385 return XT_CONTINUE;
386
387 skb->nfct = &nf_ct_untracked_get()->ct_general;
388 skb->nfctinfo = IP_CT_NEW;
389 nf_conntrack_get(skb->nfct);
390
391 return XT_CONTINUE;
392}
393
394static int notrack_chk(const struct xt_tgchk_param *par)
395{
396 if (!par->net->xt.notrack_deprecated_warning) {
397 pr_info("netfilter: NOTRACK target is deprecated, "
398 "use CT instead or upgrade iptables\n");
399 par->net->xt.notrack_deprecated_warning = true;
400 }
401 return 0;
402}
403
404static struct xt_target notrack_tg_reg __read_mostly = {
405 .name = "NOTRACK",
406 .revision = 0,
407 .family = NFPROTO_UNSPEC,
408 .checkentry = notrack_chk,
409 .target = notrack_tg,
410 .table = "raw",
411 .me = THIS_MODULE,
412};
413
414static int __init xt_ct_tg_init(void)
415{
416 int ret;
417
418 ret = xt_register_target(¬rack_tg_reg);
419 if (ret < 0)
420 return ret;
421
422 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
423 if (ret < 0) {
424 xt_unregister_target(¬rack_tg_reg);
425 return ret;
426 }
427 return 0;
428}
429
430static void __exit xt_ct_tg_exit(void)
431{
432 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
433 xt_unregister_target(¬rack_tg_reg);
434}
435
436module_init(xt_ct_tg_init);
437module_exit(xt_ct_tg_exit);
438
439MODULE_LICENSE("GPL");
440MODULE_DESCRIPTION("Xtables: connection tracking target");
441MODULE_ALIAS("ipt_CT");
442MODULE_ALIAS("ip6t_CT");
443MODULE_ALIAS("ipt_NOTRACK");
444MODULE_ALIAS("ip6t_NOTRACK");
445
