tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
32#include <net/netfilter/nf_conntrack_timeout.h>
33
34#include <linux/netfilter/nfnetlink.h>
35#include <linux/netfilter/nfnetlink_cttimeout.h>
36
37MODULE_LICENSE("GPL");
38MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
39MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tuning");
40
41static LIST_HEAD(cttimeout_list);
42
43static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = {
44 [CTA_TIMEOUT_NAME] = { .type = NLA_NUL_STRING,
45 .len = CTNL_TIMEOUT_NAME_MAX - 1},
46 [CTA_TIMEOUT_L3PROTO] = { .type = NLA_U16 },
47 [CTA_TIMEOUT_L4PROTO] = { .type = NLA_U8 },
48 [CTA_TIMEOUT_DATA] = { .type = NLA_NESTED },
49};
50
51static int
52ctnl_timeout_parse_policy(struct ctnl_timeout *timeout,
53 struct nf_conntrack_l4proto *l4proto,
54 struct net *net,
55 const struct nlattr *attr)
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 ret = nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max,
63 attr, l4proto->ctnl_timeout.nla_policy);
64 if (ret < 0)
65 return ret;
66
67 ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net,
68 &timeout->data);
69 }
70 return ret;
71}
72
73static int
74cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb,
75 const struct nlmsghdr *nlh,
76 const struct nlattr * const cda[])
77{
78 __u16 l3num;
79 __u8 l4num;
80 struct nf_conntrack_l4proto *l4proto;
81 struct ctnl_timeout *timeout, *matching = NULL;
82 struct net *net = sock_net(skb->sk);
83 char *name;
84 int ret;
85
86 if (!cda[CTA_TIMEOUT_NAME] ||
87 !cda[CTA_TIMEOUT_L3PROTO] ||
88 !cda[CTA_TIMEOUT_L4PROTO] ||
89 !cda[CTA_TIMEOUT_DATA])
90 return -EINVAL;
91
92 name = nla_data(cda[CTA_TIMEOUT_NAME]);
93 l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
94 l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
95
96 list_for_each_entry(timeout, &cttimeout_list, head) {
97 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
98 continue;
99
100 if (nlh->nlmsg_flags & NLM_F_EXCL)
101 return -EEXIST;
102
103 matching = timeout;
104 break;
105 }
106
107 l4proto = nf_ct_l4proto_find_get(l3num, l4num);
108
109 /* This protocol is not supportted, skip. */
110 if (l4proto->l4proto != l4num) {
111 ret = -EOPNOTSUPP;
112 goto err_proto_put;
113 }
114
115 if (matching) {
116 if (nlh->nlmsg_flags & NLM_F_REPLACE) {
117 /* You cannot replace one timeout policy by another of
118 * different kind, sorry.
119 */
120 if (matching->l3num != l3num ||
121 matching->l4proto->l4proto != l4num) {
122 ret = -EINVAL;
123 goto err_proto_put;
124 }
125
126 ret = ctnl_timeout_parse_policy(matching, l4proto, net,
127 cda[CTA_TIMEOUT_DATA]);
128 return ret;
129 }
130 ret = -EBUSY;
131 goto err_proto_put;
132 }
133
134 timeout = kzalloc(sizeof(struct ctnl_timeout) +
135 l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
136 if (timeout == NULL) {
137 ret = -ENOMEM;
138 goto err_proto_put;
139 }
140
141 ret = ctnl_timeout_parse_policy(timeout, l4proto, net,
142 cda[CTA_TIMEOUT_DATA]);
143 if (ret < 0)
144 goto err;
145
146 strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME]));
147 timeout->l3num = l3num;
148 timeout->l4proto = l4proto;
149 atomic_set(&timeout->refcnt, 1);
150 list_add_tail_rcu(&timeout->head, &cttimeout_list);
151
152 return 0;
153err:
154 kfree(timeout);
155err_proto_put:
156 nf_ct_l4proto_put(l4proto);
157 return ret;
158}
159
160static int
161ctnl_timeout_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
162 int event, struct ctnl_timeout *timeout)
163{
164 struct nlmsghdr *nlh;
165 struct nfgenmsg *nfmsg;
166 unsigned int flags = portid ? NLM_F_MULTI : 0;
167 struct nf_conntrack_l4proto *l4proto = timeout->l4proto;
168
169 event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8;
170 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
171 if (nlh == NULL)
172 goto nlmsg_failure;
173
174 nfmsg = nlmsg_data(nlh);
175 nfmsg->nfgen_family = AF_UNSPEC;
176 nfmsg->version = NFNETLINK_V0;
177 nfmsg->res_id = 0;
178
179 if (nla_put_string(skb, CTA_TIMEOUT_NAME, timeout->name) ||
180 nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num)) ||
181 nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4proto->l4proto) ||
182 nla_put_be32(skb, CTA_TIMEOUT_USE,
183 htonl(atomic_read(&timeout->refcnt))))
184 goto nla_put_failure;
185
186 if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
187 struct nlattr *nest_parms;
188 int ret;
189
190 nest_parms = nla_nest_start(skb,
191 CTA_TIMEOUT_DATA | NLA_F_NESTED);
192 if (!nest_parms)
193 goto nla_put_failure;
194
195 ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data);
196 if (ret < 0)
197 goto nla_put_failure;
198
199 nla_nest_end(skb, nest_parms);
200 }
201
202 nlmsg_end(skb, nlh);
203 return skb->len;
204
205nlmsg_failure:
206nla_put_failure:
207 nlmsg_cancel(skb, nlh);
208 return -1;
209}
210
211static int
212ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb)
213{
214 struct ctnl_timeout *cur, *last;
215
216 if (cb->args[2])
217 return 0;
218
219 last = (struct ctnl_timeout *)cb->args[1];
220 if (cb->args[1])
221 cb->args[1] = 0;
222
223 rcu_read_lock();
224 list_for_each_entry_rcu(cur, &cttimeout_list, head) {
225 if (last) {
226 if (cur != last)
227 continue;
228
229 last = NULL;
230 }
231 if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).portid,
232 cb->nlh->nlmsg_seq,
233 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
234 IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) {
235 cb->args[1] = (unsigned long)cur;
236 break;
237 }
238 }
239 if (!cb->args[1])
240 cb->args[2] = 1;
241 rcu_read_unlock();
242 return skb->len;
243}
244
245static int
246cttimeout_get_timeout(struct sock *ctnl, struct sk_buff *skb,
247 const struct nlmsghdr *nlh,
248 const struct nlattr * const cda[])
249{
250 int ret = -ENOENT;
251 char *name;
252 struct ctnl_timeout *cur;
253
254 if (nlh->nlmsg_flags & NLM_F_DUMP) {
255 struct netlink_dump_control c = {
256 .dump = ctnl_timeout_dump,
257 };
258 return netlink_dump_start(ctnl, skb, nlh, &c);
259 }
260
261 if (!cda[CTA_TIMEOUT_NAME])
262 return -EINVAL;
263 name = nla_data(cda[CTA_TIMEOUT_NAME]);
264
265 list_for_each_entry(cur, &cttimeout_list, head) {
266 struct sk_buff *skb2;
267
268 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
269 continue;
270
271 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
272 if (skb2 == NULL) {
273 ret = -ENOMEM;
274 break;
275 }
276
277 ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).portid,
278 nlh->nlmsg_seq,
279 NFNL_MSG_TYPE(nlh->nlmsg_type),
280 IPCTNL_MSG_TIMEOUT_NEW, cur);
281 if (ret <= 0) {
282 kfree_skb(skb2);
283 break;
284 }
285 ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid,
286 MSG_DONTWAIT);
287 if (ret > 0)
288 ret = 0;
289
290 /* this avoids a loop in nfnetlink. */
291 return ret == -EAGAIN ? -ENOBUFS : ret;
292 }
293 return ret;
294}
295
296/* try to delete object, fail if it is still in use. */
297static int ctnl_timeout_try_del(struct ctnl_timeout *timeout)
298{
299 int ret = 0;
300
301 /* we want to avoid races with nf_ct_timeout_find_get. */
302 if (atomic_dec_and_test(&timeout->refcnt)) {
303 /* We are protected by nfnl mutex. */
304 list_del_rcu(&timeout->head);
305 nf_ct_l4proto_put(timeout->l4proto);
306 kfree_rcu(timeout, rcu_head);
307 } else {
308 /* still in use, restore reference counter. */
309 atomic_inc(&timeout->refcnt);
310 ret = -EBUSY;
311 }
312 return ret;
313}
314
315static int
316cttimeout_del_timeout(struct sock *ctnl, struct sk_buff *skb,
317 const struct nlmsghdr *nlh,
318 const struct nlattr * const cda[])
319{
320 char *name;
321 struct ctnl_timeout *cur;
322 int ret = -ENOENT;
323
324 if (!cda[CTA_TIMEOUT_NAME]) {
325 list_for_each_entry(cur, &cttimeout_list, head)
326 ctnl_timeout_try_del(cur);
327
328 return 0;
329 }
330 name = nla_data(cda[CTA_TIMEOUT_NAME]);
331
332 list_for_each_entry(cur, &cttimeout_list, head) {
333 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
334 continue;
335
336 ret = ctnl_timeout_try_del(cur);
337 if (ret < 0)
338 return ret;
339
340 break;
341 }
342 return ret;
343}
344
345#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
346static struct ctnl_timeout *ctnl_timeout_find_get(const char *name)
347{
348 struct ctnl_timeout *timeout, *matching = NULL;
349
350 rcu_read_lock();
351 list_for_each_entry_rcu(timeout, &cttimeout_list, head) {
352 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
353 continue;
354
355 if (!try_module_get(THIS_MODULE))
356 goto err;
357
358 if (!atomic_inc_not_zero(&timeout->refcnt)) {
359 module_put(THIS_MODULE);
360 goto err;
361 }
362 matching = timeout;
363 break;
364 }
365err:
366 rcu_read_unlock();
367 return matching;
368}
369
370static void ctnl_timeout_put(struct ctnl_timeout *timeout)
371{
372 atomic_dec(&timeout->refcnt);
373 module_put(THIS_MODULE);
374}
375#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
376
377static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
378 [IPCTNL_MSG_TIMEOUT_NEW] = { .call = cttimeout_new_timeout,
379 .attr_count = CTA_TIMEOUT_MAX,
380 .policy = cttimeout_nla_policy },
381 [IPCTNL_MSG_TIMEOUT_GET] = { .call = cttimeout_get_timeout,
382 .attr_count = CTA_TIMEOUT_MAX,
383 .policy = cttimeout_nla_policy },
384 [IPCTNL_MSG_TIMEOUT_DELETE] = { .call = cttimeout_del_timeout,
385 .attr_count = CTA_TIMEOUT_MAX,
386 .policy = cttimeout_nla_policy },
387};
388
389static const struct nfnetlink_subsystem cttimeout_subsys = {
390 .name = "conntrack_timeout",
391 .subsys_id = NFNL_SUBSYS_CTNETLINK_TIMEOUT,
392 .cb_count = IPCTNL_MSG_TIMEOUT_MAX,
393 .cb = cttimeout_cb,
394};
395
396MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);
397
398static int __init cttimeout_init(void)
399{
400 int ret;
401
402 ret = nfnetlink_subsys_register(&cttimeout_subsys);
403 if (ret < 0) {
404 pr_err("cttimeout_init: cannot register cttimeout with "
405 "nfnetlink.\n");
406 goto err_out;
407 }
408#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
409 RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get);
410 RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put);
411#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
412 return 0;
413
414err_out:
415 return ret;
416}
417
418static void __exit cttimeout_exit(void)
419{
420 struct ctnl_timeout *cur, *tmp;
421
422 pr_info("cttimeout: unregistering from nfnetlink.\n");
423
424 nfnetlink_subsys_unregister(&cttimeout_subsys);
425 list_for_each_entry_safe(cur, tmp, &cttimeout_list, head) {
426 list_del_rcu(&cur->head);
427 /* We are sure that our objects have no clients at this point,
428 * it's safe to release them all without checking refcnt.
429 */
430 nf_ct_l4proto_put(cur->l4proto);
431 kfree_rcu(cur, rcu_head);
432 }
433#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
434 RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL);
435 RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL);
436#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
437}
438
439module_init(cttimeout_init);
440module_exit(cttimeout_exit);