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50978462 PNA |
1 | /* |
2 | * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org> | |
3 | * (C) 2012 by Vyatta Inc. <http://www.vyatta.com> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation (or any later at your option). | |
8 | */ | |
9 | #include <linux/init.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/kernel.h> | |
12 | #include <linux/rculist.h> | |
13 | #include <linux/rculist_nulls.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/timer.h> | |
16 | #include <linux/security.h> | |
17 | #include <linux/skbuff.h> | |
18 | #include <linux/errno.h> | |
19 | #include <linux/netlink.h> | |
20 | #include <linux/spinlock.h> | |
21 | #include <linux/interrupt.h> | |
22 | #include <linux/slab.h> | |
23 | ||
24 | #include <linux/netfilter.h> | |
25 | #include <net/netlink.h> | |
26 | #include <net/sock.h> | |
27 | #include <net/netfilter/nf_conntrack.h> | |
28 | #include <net/netfilter/nf_conntrack_core.h> | |
29 | #include <net/netfilter/nf_conntrack_l3proto.h> | |
30 | #include <net/netfilter/nf_conntrack_l4proto.h> | |
31 | #include <net/netfilter/nf_conntrack_tuple.h> | |
24de58f4 | 32 | #include <net/netfilter/nf_conntrack_timeout.h> |
50978462 PNA |
33 | |
34 | #include <linux/netfilter/nfnetlink.h> | |
35 | #include <linux/netfilter/nfnetlink_cttimeout.h> | |
36 | ||
37 | MODULE_LICENSE("GPL"); | |
38 | MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); | |
39 | MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tuning"); | |
40 | ||
50978462 PNA |
41 | static LIST_HEAD(cttimeout_list); |
42 | ||
43 | static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = { | |
44 | [CTA_TIMEOUT_NAME] = { .type = NLA_NUL_STRING }, | |
45 | [CTA_TIMEOUT_L3PROTO] = { .type = NLA_U16 }, | |
46 | [CTA_TIMEOUT_L4PROTO] = { .type = NLA_U8 }, | |
47 | [CTA_TIMEOUT_DATA] = { .type = NLA_NESTED }, | |
48 | }; | |
49 | ||
50 | static int | |
51 | ctnl_timeout_parse_policy(struct ctnl_timeout *timeout, | |
8264deb8 G |
52 | struct nf_conntrack_l4proto *l4proto, |
53 | struct net *net, | |
54 | const struct nlattr *attr) | |
50978462 PNA |
55 | { |
56 | int ret = 0; | |
57 | ||
58 | if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) { | |
59 | struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1]; | |
60 | ||
61 | nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max, | |
62 | attr, l4proto->ctnl_timeout.nla_policy); | |
63 | ||
8264deb8 G |
64 | ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net, |
65 | &timeout->data); | |
50978462 PNA |
66 | } |
67 | return ret; | |
68 | } | |
69 | ||
70 | static int | |
71 | cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb, | |
72 | const struct nlmsghdr *nlh, | |
73 | const struct nlattr * const cda[]) | |
74 | { | |
75 | __u16 l3num; | |
76 | __u8 l4num; | |
77 | struct nf_conntrack_l4proto *l4proto; | |
78 | struct ctnl_timeout *timeout, *matching = NULL; | |
8264deb8 | 79 | struct net *net = sock_net(skb->sk); |
50978462 PNA |
80 | char *name; |
81 | int ret; | |
82 | ||
83 | if (!cda[CTA_TIMEOUT_NAME] || | |
84 | !cda[CTA_TIMEOUT_L3PROTO] || | |
85 | !cda[CTA_TIMEOUT_L4PROTO] || | |
86 | !cda[CTA_TIMEOUT_DATA]) | |
87 | return -EINVAL; | |
88 | ||
89 | name = nla_data(cda[CTA_TIMEOUT_NAME]); | |
90 | l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO])); | |
91 | l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]); | |
92 | ||
93 | list_for_each_entry(timeout, &cttimeout_list, head) { | |
94 | if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) | |
95 | continue; | |
96 | ||
97 | if (nlh->nlmsg_flags & NLM_F_EXCL) | |
98 | return -EEXIST; | |
99 | ||
100 | matching = timeout; | |
101 | break; | |
102 | } | |
103 | ||
c1ebd7df | 104 | l4proto = nf_ct_l4proto_find_get(l3num, l4num); |
50978462 PNA |
105 | |
106 | /* This protocol is not supportted, skip. */ | |
c1ebd7df PNA |
107 | if (l4proto->l4proto != l4num) { |
108 | ret = -EOPNOTSUPP; | |
109 | goto err_proto_put; | |
110 | } | |
50978462 PNA |
111 | |
112 | if (matching) { | |
113 | if (nlh->nlmsg_flags & NLM_F_REPLACE) { | |
114 | /* You cannot replace one timeout policy by another of | |
115 | * different kind, sorry. | |
116 | */ | |
117 | if (matching->l3num != l3num || | |
c1ebd7df PNA |
118 | matching->l4proto->l4proto != l4num) { |
119 | ret = -EINVAL; | |
120 | goto err_proto_put; | |
121 | } | |
50978462 | 122 | |
8264deb8 | 123 | ret = ctnl_timeout_parse_policy(matching, l4proto, net, |
50978462 PNA |
124 | cda[CTA_TIMEOUT_DATA]); |
125 | return ret; | |
126 | } | |
c1ebd7df PNA |
127 | ret = -EBUSY; |
128 | goto err_proto_put; | |
50978462 PNA |
129 | } |
130 | ||
131 | timeout = kzalloc(sizeof(struct ctnl_timeout) + | |
132 | l4proto->ctnl_timeout.obj_size, GFP_KERNEL); | |
c1ebd7df PNA |
133 | if (timeout == NULL) { |
134 | ret = -ENOMEM; | |
135 | goto err_proto_put; | |
136 | } | |
50978462 | 137 | |
8264deb8 | 138 | ret = ctnl_timeout_parse_policy(timeout, l4proto, net, |
50978462 PNA |
139 | cda[CTA_TIMEOUT_DATA]); |
140 | if (ret < 0) | |
141 | goto err; | |
142 | ||
143 | strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME])); | |
144 | timeout->l3num = l3num; | |
c1ebd7df | 145 | timeout->l4proto = l4proto; |
50978462 PNA |
146 | atomic_set(&timeout->refcnt, 1); |
147 | list_add_tail_rcu(&timeout->head, &cttimeout_list); | |
148 | ||
149 | return 0; | |
150 | err: | |
151 | kfree(timeout); | |
c1ebd7df PNA |
152 | err_proto_put: |
153 | nf_ct_l4proto_put(l4proto); | |
50978462 PNA |
154 | return ret; |
155 | } | |
156 | ||
157 | static int | |
15e47304 | 158 | ctnl_timeout_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type, |
50978462 PNA |
159 | int event, struct ctnl_timeout *timeout) |
160 | { | |
161 | struct nlmsghdr *nlh; | |
162 | struct nfgenmsg *nfmsg; | |
15e47304 | 163 | unsigned int flags = portid ? NLM_F_MULTI : 0; |
c1ebd7df | 164 | struct nf_conntrack_l4proto *l4proto = timeout->l4proto; |
50978462 PNA |
165 | |
166 | event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8; | |
15e47304 | 167 | nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags); |
50978462 PNA |
168 | if (nlh == NULL) |
169 | goto nlmsg_failure; | |
170 | ||
171 | nfmsg = nlmsg_data(nlh); | |
172 | nfmsg->nfgen_family = AF_UNSPEC; | |
173 | nfmsg->version = NFNETLINK_V0; | |
174 | nfmsg->res_id = 0; | |
175 | ||
48f03bda DM |
176 | if (nla_put_string(skb, CTA_TIMEOUT_NAME, timeout->name) || |
177 | nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num)) || | |
178 | nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4proto->l4proto) || | |
179 | nla_put_be32(skb, CTA_TIMEOUT_USE, | |
180 | htonl(atomic_read(&timeout->refcnt)))) | |
181 | goto nla_put_failure; | |
50978462 | 182 | |
50978462 PNA |
183 | if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) { |
184 | struct nlattr *nest_parms; | |
185 | int ret; | |
186 | ||
187 | nest_parms = nla_nest_start(skb, | |
188 | CTA_TIMEOUT_DATA | NLA_F_NESTED); | |
189 | if (!nest_parms) | |
190 | goto nla_put_failure; | |
191 | ||
192 | ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data); | |
193 | if (ret < 0) | |
194 | goto nla_put_failure; | |
195 | ||
196 | nla_nest_end(skb, nest_parms); | |
197 | } | |
c1ebd7df | 198 | |
50978462 PNA |
199 | nlmsg_end(skb, nlh); |
200 | return skb->len; | |
201 | ||
202 | nlmsg_failure: | |
203 | nla_put_failure: | |
204 | nlmsg_cancel(skb, nlh); | |
205 | return -1; | |
206 | } | |
207 | ||
208 | static int | |
209 | ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb) | |
210 | { | |
211 | struct ctnl_timeout *cur, *last; | |
212 | ||
213 | if (cb->args[2]) | |
214 | return 0; | |
215 | ||
216 | last = (struct ctnl_timeout *)cb->args[1]; | |
217 | if (cb->args[1]) | |
218 | cb->args[1] = 0; | |
219 | ||
220 | rcu_read_lock(); | |
221 | list_for_each_entry_rcu(cur, &cttimeout_list, head) { | |
222 | if (last && cur != last) | |
223 | continue; | |
224 | ||
15e47304 | 225 | if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).portid, |
50978462 PNA |
226 | cb->nlh->nlmsg_seq, |
227 | NFNL_MSG_TYPE(cb->nlh->nlmsg_type), | |
228 | IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) { | |
229 | cb->args[1] = (unsigned long)cur; | |
230 | break; | |
231 | } | |
232 | } | |
233 | if (!cb->args[1]) | |
234 | cb->args[2] = 1; | |
235 | rcu_read_unlock(); | |
236 | return skb->len; | |
237 | } | |
238 | ||
239 | static int | |
240 | cttimeout_get_timeout(struct sock *ctnl, struct sk_buff *skb, | |
241 | const struct nlmsghdr *nlh, | |
242 | const struct nlattr * const cda[]) | |
243 | { | |
244 | int ret = -ENOENT; | |
245 | char *name; | |
246 | struct ctnl_timeout *cur; | |
247 | ||
248 | if (nlh->nlmsg_flags & NLM_F_DUMP) { | |
249 | struct netlink_dump_control c = { | |
250 | .dump = ctnl_timeout_dump, | |
251 | }; | |
252 | return netlink_dump_start(ctnl, skb, nlh, &c); | |
253 | } | |
254 | ||
255 | if (!cda[CTA_TIMEOUT_NAME]) | |
256 | return -EINVAL; | |
257 | name = nla_data(cda[CTA_TIMEOUT_NAME]); | |
258 | ||
259 | list_for_each_entry(cur, &cttimeout_list, head) { | |
260 | struct sk_buff *skb2; | |
261 | ||
262 | if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) | |
263 | continue; | |
264 | ||
265 | skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); | |
266 | if (skb2 == NULL) { | |
267 | ret = -ENOMEM; | |
268 | break; | |
269 | } | |
270 | ||
15e47304 | 271 | ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).portid, |
50978462 PNA |
272 | nlh->nlmsg_seq, |
273 | NFNL_MSG_TYPE(nlh->nlmsg_type), | |
274 | IPCTNL_MSG_TIMEOUT_NEW, cur); | |
275 | if (ret <= 0) { | |
276 | kfree_skb(skb2); | |
277 | break; | |
278 | } | |
15e47304 | 279 | ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid, |
50978462 PNA |
280 | MSG_DONTWAIT); |
281 | if (ret > 0) | |
282 | ret = 0; | |
283 | ||
284 | /* this avoids a loop in nfnetlink. */ | |
285 | return ret == -EAGAIN ? -ENOBUFS : ret; | |
286 | } | |
287 | return ret; | |
288 | } | |
289 | ||
290 | /* try to delete object, fail if it is still in use. */ | |
291 | static int ctnl_timeout_try_del(struct ctnl_timeout *timeout) | |
292 | { | |
293 | int ret = 0; | |
294 | ||
295 | /* we want to avoid races with nf_ct_timeout_find_get. */ | |
296 | if (atomic_dec_and_test(&timeout->refcnt)) { | |
297 | /* We are protected by nfnl mutex. */ | |
298 | list_del_rcu(&timeout->head); | |
c1ebd7df | 299 | nf_ct_l4proto_put(timeout->l4proto); |
50978462 PNA |
300 | kfree_rcu(timeout, rcu_head); |
301 | } else { | |
302 | /* still in use, restore reference counter. */ | |
303 | atomic_inc(&timeout->refcnt); | |
304 | ret = -EBUSY; | |
305 | } | |
306 | return ret; | |
307 | } | |
308 | ||
309 | static int | |
310 | cttimeout_del_timeout(struct sock *ctnl, struct sk_buff *skb, | |
311 | const struct nlmsghdr *nlh, | |
312 | const struct nlattr * const cda[]) | |
313 | { | |
314 | char *name; | |
315 | struct ctnl_timeout *cur; | |
316 | int ret = -ENOENT; | |
317 | ||
318 | if (!cda[CTA_TIMEOUT_NAME]) { | |
319 | list_for_each_entry(cur, &cttimeout_list, head) | |
320 | ctnl_timeout_try_del(cur); | |
321 | ||
322 | return 0; | |
323 | } | |
324 | name = nla_data(cda[CTA_TIMEOUT_NAME]); | |
325 | ||
326 | list_for_each_entry(cur, &cttimeout_list, head) { | |
327 | if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) | |
328 | continue; | |
329 | ||
330 | ret = ctnl_timeout_try_del(cur); | |
331 | if (ret < 0) | |
332 | return ret; | |
333 | ||
334 | break; | |
335 | } | |
336 | return ret; | |
337 | } | |
338 | ||
24de58f4 PNA |
339 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
340 | static struct ctnl_timeout *ctnl_timeout_find_get(const char *name) | |
341 | { | |
342 | struct ctnl_timeout *timeout, *matching = NULL; | |
343 | ||
344 | rcu_read_lock(); | |
345 | list_for_each_entry_rcu(timeout, &cttimeout_list, head) { | |
346 | if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) | |
347 | continue; | |
348 | ||
349 | if (!try_module_get(THIS_MODULE)) | |
350 | goto err; | |
351 | ||
352 | if (!atomic_inc_not_zero(&timeout->refcnt)) { | |
353 | module_put(THIS_MODULE); | |
354 | goto err; | |
355 | } | |
356 | matching = timeout; | |
357 | break; | |
358 | } | |
359 | err: | |
360 | rcu_read_unlock(); | |
361 | return matching; | |
362 | } | |
363 | ||
364 | static void ctnl_timeout_put(struct ctnl_timeout *timeout) | |
365 | { | |
366 | atomic_dec(&timeout->refcnt); | |
367 | module_put(THIS_MODULE); | |
368 | } | |
369 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ | |
370 | ||
50978462 PNA |
371 | static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = { |
372 | [IPCTNL_MSG_TIMEOUT_NEW] = { .call = cttimeout_new_timeout, | |
373 | .attr_count = CTA_TIMEOUT_MAX, | |
374 | .policy = cttimeout_nla_policy }, | |
375 | [IPCTNL_MSG_TIMEOUT_GET] = { .call = cttimeout_get_timeout, | |
376 | .attr_count = CTA_TIMEOUT_MAX, | |
377 | .policy = cttimeout_nla_policy }, | |
378 | [IPCTNL_MSG_TIMEOUT_DELETE] = { .call = cttimeout_del_timeout, | |
379 | .attr_count = CTA_TIMEOUT_MAX, | |
380 | .policy = cttimeout_nla_policy }, | |
381 | }; | |
382 | ||
383 | static const struct nfnetlink_subsystem cttimeout_subsys = { | |
384 | .name = "conntrack_timeout", | |
385 | .subsys_id = NFNL_SUBSYS_CTNETLINK_TIMEOUT, | |
386 | .cb_count = IPCTNL_MSG_TIMEOUT_MAX, | |
387 | .cb = cttimeout_cb, | |
388 | }; | |
389 | ||
390 | MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT); | |
391 | ||
392 | static int __init cttimeout_init(void) | |
393 | { | |
394 | int ret; | |
395 | ||
396 | ret = nfnetlink_subsys_register(&cttimeout_subsys); | |
397 | if (ret < 0) { | |
398 | pr_err("cttimeout_init: cannot register cttimeout with " | |
399 | "nfnetlink.\n"); | |
400 | goto err_out; | |
401 | } | |
24de58f4 PNA |
402 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
403 | RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get); | |
404 | RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put); | |
405 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ | |
50978462 PNA |
406 | return 0; |
407 | ||
408 | err_out: | |
409 | return ret; | |
410 | } | |
411 | ||
412 | static void __exit cttimeout_exit(void) | |
413 | { | |
414 | struct ctnl_timeout *cur, *tmp; | |
415 | ||
416 | pr_info("cttimeout: unregistering from nfnetlink.\n"); | |
417 | ||
418 | nfnetlink_subsys_unregister(&cttimeout_subsys); | |
419 | list_for_each_entry_safe(cur, tmp, &cttimeout_list, head) { | |
420 | list_del_rcu(&cur->head); | |
421 | /* We are sure that our objects have no clients at this point, | |
422 | * it's safe to release them all without checking refcnt. | |
423 | */ | |
c1ebd7df | 424 | nf_ct_l4proto_put(cur->l4proto); |
50978462 PNA |
425 | kfree_rcu(cur, rcu_head); |
426 | } | |
24de58f4 PNA |
427 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
428 | RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL); | |
429 | RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL); | |
430 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ | |
50978462 PNA |
431 | } |
432 | ||
433 | module_init(cttimeout_init); | |
434 | module_exit(cttimeout_exit); |