Commit | Line | Data |
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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] = { | |
e93b5f9f FW |
44 | [CTA_TIMEOUT_NAME] = { .type = NLA_NUL_STRING, |
45 | .len = CTNL_TIMEOUT_NAME_MAX - 1}, | |
50978462 PNA |
46 | [CTA_TIMEOUT_L3PROTO] = { .type = NLA_U16 }, |
47 | [CTA_TIMEOUT_L4PROTO] = { .type = NLA_U8 }, | |
48 | [CTA_TIMEOUT_DATA] = { .type = NLA_NESTED }, | |
49 | }; | |
50 | ||
51 | static int | |
52 | ctnl_timeout_parse_policy(struct ctnl_timeout *timeout, | |
8264deb8 G |
53 | struct nf_conntrack_l4proto *l4proto, |
54 | struct net *net, | |
55 | const struct nlattr *attr) | |
50978462 PNA |
56 | { |
57 | int ret = 0; | |
58 | ||
59 | if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) { | |
60 | struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1]; | |
61 | ||
62 | nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max, | |
63 | attr, l4proto->ctnl_timeout.nla_policy); | |
64 | ||
8264deb8 G |
65 | ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net, |
66 | &timeout->data); | |
50978462 PNA |
67 | } |
68 | return ret; | |
69 | } | |
70 | ||
71 | static int | |
72 | cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb, | |
73 | const struct nlmsghdr *nlh, | |
74 | const struct nlattr * const cda[]) | |
75 | { | |
76 | __u16 l3num; | |
77 | __u8 l4num; | |
78 | struct nf_conntrack_l4proto *l4proto; | |
79 | struct ctnl_timeout *timeout, *matching = NULL; | |
8264deb8 | 80 | struct net *net = sock_net(skb->sk); |
50978462 PNA |
81 | char *name; |
82 | int ret; | |
83 | ||
84 | if (!cda[CTA_TIMEOUT_NAME] || | |
85 | !cda[CTA_TIMEOUT_L3PROTO] || | |
86 | !cda[CTA_TIMEOUT_L4PROTO] || | |
87 | !cda[CTA_TIMEOUT_DATA]) | |
88 | return -EINVAL; | |
89 | ||
90 | name = nla_data(cda[CTA_TIMEOUT_NAME]); | |
91 | l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO])); | |
92 | l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]); | |
93 | ||
94 | list_for_each_entry(timeout, &cttimeout_list, head) { | |
95 | if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) | |
96 | continue; | |
97 | ||
98 | if (nlh->nlmsg_flags & NLM_F_EXCL) | |
99 | return -EEXIST; | |
100 | ||
101 | matching = timeout; | |
102 | break; | |
103 | } | |
104 | ||
c1ebd7df | 105 | l4proto = nf_ct_l4proto_find_get(l3num, l4num); |
50978462 PNA |
106 | |
107 | /* This protocol is not supportted, skip. */ | |
c1ebd7df PNA |
108 | if (l4proto->l4proto != l4num) { |
109 | ret = -EOPNOTSUPP; | |
110 | goto err_proto_put; | |
111 | } | |
50978462 PNA |
112 | |
113 | if (matching) { | |
114 | if (nlh->nlmsg_flags & NLM_F_REPLACE) { | |
115 | /* You cannot replace one timeout policy by another of | |
116 | * different kind, sorry. | |
117 | */ | |
118 | if (matching->l3num != l3num || | |
c1ebd7df PNA |
119 | matching->l4proto->l4proto != l4num) { |
120 | ret = -EINVAL; | |
121 | goto err_proto_put; | |
122 | } | |
50978462 | 123 | |
8264deb8 | 124 | ret = ctnl_timeout_parse_policy(matching, l4proto, net, |
50978462 PNA |
125 | cda[CTA_TIMEOUT_DATA]); |
126 | return ret; | |
127 | } | |
c1ebd7df PNA |
128 | ret = -EBUSY; |
129 | goto err_proto_put; | |
50978462 PNA |
130 | } |
131 | ||
132 | timeout = kzalloc(sizeof(struct ctnl_timeout) + | |
133 | l4proto->ctnl_timeout.obj_size, GFP_KERNEL); | |
c1ebd7df PNA |
134 | if (timeout == NULL) { |
135 | ret = -ENOMEM; | |
136 | goto err_proto_put; | |
137 | } | |
50978462 | 138 | |
8264deb8 | 139 | ret = ctnl_timeout_parse_policy(timeout, l4proto, net, |
50978462 PNA |
140 | cda[CTA_TIMEOUT_DATA]); |
141 | if (ret < 0) | |
142 | goto err; | |
143 | ||
144 | strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME])); | |
145 | timeout->l3num = l3num; | |
c1ebd7df | 146 | timeout->l4proto = l4proto; |
50978462 PNA |
147 | atomic_set(&timeout->refcnt, 1); |
148 | list_add_tail_rcu(&timeout->head, &cttimeout_list); | |
149 | ||
150 | return 0; | |
151 | err: | |
152 | kfree(timeout); | |
c1ebd7df PNA |
153 | err_proto_put: |
154 | nf_ct_l4proto_put(l4proto); | |
50978462 PNA |
155 | return ret; |
156 | } | |
157 | ||
158 | static int | |
15e47304 | 159 | ctnl_timeout_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type, |
50978462 PNA |
160 | int event, struct ctnl_timeout *timeout) |
161 | { | |
162 | struct nlmsghdr *nlh; | |
163 | struct nfgenmsg *nfmsg; | |
15e47304 | 164 | unsigned int flags = portid ? NLM_F_MULTI : 0; |
c1ebd7df | 165 | struct nf_conntrack_l4proto *l4proto = timeout->l4proto; |
50978462 PNA |
166 | |
167 | event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8; | |
15e47304 | 168 | nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags); |
50978462 PNA |
169 | if (nlh == NULL) |
170 | goto nlmsg_failure; | |
171 | ||
172 | nfmsg = nlmsg_data(nlh); | |
173 | nfmsg->nfgen_family = AF_UNSPEC; | |
174 | nfmsg->version = NFNETLINK_V0; | |
175 | nfmsg->res_id = 0; | |
176 | ||
48f03bda DM |
177 | if (nla_put_string(skb, CTA_TIMEOUT_NAME, timeout->name) || |
178 | nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num)) || | |
179 | nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4proto->l4proto) || | |
180 | nla_put_be32(skb, CTA_TIMEOUT_USE, | |
181 | htonl(atomic_read(&timeout->refcnt)))) | |
182 | goto nla_put_failure; | |
50978462 | 183 | |
50978462 PNA |
184 | if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) { |
185 | struct nlattr *nest_parms; | |
186 | int ret; | |
187 | ||
188 | nest_parms = nla_nest_start(skb, | |
189 | CTA_TIMEOUT_DATA | NLA_F_NESTED); | |
190 | if (!nest_parms) | |
191 | goto nla_put_failure; | |
192 | ||
193 | ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data); | |
194 | if (ret < 0) | |
195 | goto nla_put_failure; | |
196 | ||
197 | nla_nest_end(skb, nest_parms); | |
198 | } | |
c1ebd7df | 199 | |
50978462 PNA |
200 | nlmsg_end(skb, nlh); |
201 | return skb->len; | |
202 | ||
203 | nlmsg_failure: | |
204 | nla_put_failure: | |
205 | nlmsg_cancel(skb, nlh); | |
206 | return -1; | |
207 | } | |
208 | ||
209 | static int | |
210 | ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb) | |
211 | { | |
212 | struct ctnl_timeout *cur, *last; | |
213 | ||
214 | if (cb->args[2]) | |
215 | return 0; | |
216 | ||
217 | last = (struct ctnl_timeout *)cb->args[1]; | |
218 | if (cb->args[1]) | |
219 | cb->args[1] = 0; | |
220 | ||
221 | rcu_read_lock(); | |
222 | list_for_each_entry_rcu(cur, &cttimeout_list, head) { | |
223 | if (last && cur != last) | |
224 | continue; | |
225 | ||
15e47304 | 226 | if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).portid, |
50978462 PNA |
227 | cb->nlh->nlmsg_seq, |
228 | NFNL_MSG_TYPE(cb->nlh->nlmsg_type), | |
229 | IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) { | |
230 | cb->args[1] = (unsigned long)cur; | |
231 | break; | |
232 | } | |
233 | } | |
234 | if (!cb->args[1]) | |
235 | cb->args[2] = 1; | |
236 | rcu_read_unlock(); | |
237 | return skb->len; | |
238 | } | |
239 | ||
240 | static int | |
241 | cttimeout_get_timeout(struct sock *ctnl, struct sk_buff *skb, | |
242 | const struct nlmsghdr *nlh, | |
243 | const struct nlattr * const cda[]) | |
244 | { | |
245 | int ret = -ENOENT; | |
246 | char *name; | |
247 | struct ctnl_timeout *cur; | |
248 | ||
249 | if (nlh->nlmsg_flags & NLM_F_DUMP) { | |
250 | struct netlink_dump_control c = { | |
251 | .dump = ctnl_timeout_dump, | |
252 | }; | |
253 | return netlink_dump_start(ctnl, skb, nlh, &c); | |
254 | } | |
255 | ||
256 | if (!cda[CTA_TIMEOUT_NAME]) | |
257 | return -EINVAL; | |
258 | name = nla_data(cda[CTA_TIMEOUT_NAME]); | |
259 | ||
260 | list_for_each_entry(cur, &cttimeout_list, head) { | |
261 | struct sk_buff *skb2; | |
262 | ||
263 | if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) | |
264 | continue; | |
265 | ||
266 | skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); | |
267 | if (skb2 == NULL) { | |
268 | ret = -ENOMEM; | |
269 | break; | |
270 | } | |
271 | ||
15e47304 | 272 | ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).portid, |
50978462 PNA |
273 | nlh->nlmsg_seq, |
274 | NFNL_MSG_TYPE(nlh->nlmsg_type), | |
275 | IPCTNL_MSG_TIMEOUT_NEW, cur); | |
276 | if (ret <= 0) { | |
277 | kfree_skb(skb2); | |
278 | break; | |
279 | } | |
15e47304 | 280 | ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid, |
50978462 PNA |
281 | MSG_DONTWAIT); |
282 | if (ret > 0) | |
283 | ret = 0; | |
284 | ||
285 | /* this avoids a loop in nfnetlink. */ | |
286 | return ret == -EAGAIN ? -ENOBUFS : ret; | |
287 | } | |
288 | return ret; | |
289 | } | |
290 | ||
291 | /* try to delete object, fail if it is still in use. */ | |
292 | static int ctnl_timeout_try_del(struct ctnl_timeout *timeout) | |
293 | { | |
294 | int ret = 0; | |
295 | ||
296 | /* we want to avoid races with nf_ct_timeout_find_get. */ | |
297 | if (atomic_dec_and_test(&timeout->refcnt)) { | |
298 | /* We are protected by nfnl mutex. */ | |
299 | list_del_rcu(&timeout->head); | |
c1ebd7df | 300 | nf_ct_l4proto_put(timeout->l4proto); |
50978462 PNA |
301 | kfree_rcu(timeout, rcu_head); |
302 | } else { | |
303 | /* still in use, restore reference counter. */ | |
304 | atomic_inc(&timeout->refcnt); | |
305 | ret = -EBUSY; | |
306 | } | |
307 | return ret; | |
308 | } | |
309 | ||
310 | static int | |
311 | cttimeout_del_timeout(struct sock *ctnl, struct sk_buff *skb, | |
312 | const struct nlmsghdr *nlh, | |
313 | const struct nlattr * const cda[]) | |
314 | { | |
315 | char *name; | |
316 | struct ctnl_timeout *cur; | |
317 | int ret = -ENOENT; | |
318 | ||
319 | if (!cda[CTA_TIMEOUT_NAME]) { | |
320 | list_for_each_entry(cur, &cttimeout_list, head) | |
321 | ctnl_timeout_try_del(cur); | |
322 | ||
323 | return 0; | |
324 | } | |
325 | name = nla_data(cda[CTA_TIMEOUT_NAME]); | |
326 | ||
327 | list_for_each_entry(cur, &cttimeout_list, head) { | |
328 | if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) | |
329 | continue; | |
330 | ||
331 | ret = ctnl_timeout_try_del(cur); | |
332 | if (ret < 0) | |
333 | return ret; | |
334 | ||
335 | break; | |
336 | } | |
337 | return ret; | |
338 | } | |
339 | ||
24de58f4 PNA |
340 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
341 | static struct ctnl_timeout *ctnl_timeout_find_get(const char *name) | |
342 | { | |
343 | struct ctnl_timeout *timeout, *matching = NULL; | |
344 | ||
345 | rcu_read_lock(); | |
346 | list_for_each_entry_rcu(timeout, &cttimeout_list, head) { | |
347 | if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) | |
348 | continue; | |
349 | ||
350 | if (!try_module_get(THIS_MODULE)) | |
351 | goto err; | |
352 | ||
353 | if (!atomic_inc_not_zero(&timeout->refcnt)) { | |
354 | module_put(THIS_MODULE); | |
355 | goto err; | |
356 | } | |
357 | matching = timeout; | |
358 | break; | |
359 | } | |
360 | err: | |
361 | rcu_read_unlock(); | |
362 | return matching; | |
363 | } | |
364 | ||
365 | static void ctnl_timeout_put(struct ctnl_timeout *timeout) | |
366 | { | |
367 | atomic_dec(&timeout->refcnt); | |
368 | module_put(THIS_MODULE); | |
369 | } | |
370 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ | |
371 | ||
50978462 PNA |
372 | static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = { |
373 | [IPCTNL_MSG_TIMEOUT_NEW] = { .call = cttimeout_new_timeout, | |
374 | .attr_count = CTA_TIMEOUT_MAX, | |
375 | .policy = cttimeout_nla_policy }, | |
376 | [IPCTNL_MSG_TIMEOUT_GET] = { .call = cttimeout_get_timeout, | |
377 | .attr_count = CTA_TIMEOUT_MAX, | |
378 | .policy = cttimeout_nla_policy }, | |
379 | [IPCTNL_MSG_TIMEOUT_DELETE] = { .call = cttimeout_del_timeout, | |
380 | .attr_count = CTA_TIMEOUT_MAX, | |
381 | .policy = cttimeout_nla_policy }, | |
382 | }; | |
383 | ||
384 | static const struct nfnetlink_subsystem cttimeout_subsys = { | |
385 | .name = "conntrack_timeout", | |
386 | .subsys_id = NFNL_SUBSYS_CTNETLINK_TIMEOUT, | |
387 | .cb_count = IPCTNL_MSG_TIMEOUT_MAX, | |
388 | .cb = cttimeout_cb, | |
389 | }; | |
390 | ||
391 | MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT); | |
392 | ||
393 | static int __init cttimeout_init(void) | |
394 | { | |
395 | int ret; | |
396 | ||
397 | ret = nfnetlink_subsys_register(&cttimeout_subsys); | |
398 | if (ret < 0) { | |
399 | pr_err("cttimeout_init: cannot register cttimeout with " | |
400 | "nfnetlink.\n"); | |
401 | goto err_out; | |
402 | } | |
24de58f4 PNA |
403 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
404 | RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get); | |
405 | RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put); | |
406 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ | |
50978462 PNA |
407 | return 0; |
408 | ||
409 | err_out: | |
410 | return ret; | |
411 | } | |
412 | ||
413 | static void __exit cttimeout_exit(void) | |
414 | { | |
415 | struct ctnl_timeout *cur, *tmp; | |
416 | ||
417 | pr_info("cttimeout: unregistering from nfnetlink.\n"); | |
418 | ||
419 | nfnetlink_subsys_unregister(&cttimeout_subsys); | |
420 | list_for_each_entry_safe(cur, tmp, &cttimeout_list, head) { | |
421 | list_del_rcu(&cur->head); | |
422 | /* We are sure that our objects have no clients at this point, | |
423 | * it's safe to release them all without checking refcnt. | |
424 | */ | |
c1ebd7df | 425 | nf_ct_l4proto_put(cur->l4proto); |
50978462 PNA |
426 | kfree_rcu(cur, rcu_head); |
427 | } | |
24de58f4 PNA |
428 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
429 | RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL); | |
430 | RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL); | |
431 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ | |
50978462 PNA |
432 | } |
433 | ||
434 | module_init(cttimeout_init); | |
435 | module_exit(cttimeout_exit); |