2 * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
3 * (C) 2012 by Vyatta Inc. <http://www.vyatta.com>
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).
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>
24 #include <linux/netfilter.h>
25 #include <net/netlink.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>
34 #include <linux/netfilter/nfnetlink.h>
35 #include <linux/netfilter/nfnetlink_cttimeout.h>
37 MODULE_LICENSE("GPL");
38 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
39 MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tuning");
41 static LIST_HEAD(cttimeout_list);
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 },
51 ctnl_timeout_parse_policy(struct ctnl_timeout *timeout,
52 struct nf_conntrack_l4proto *l4proto,
53 const struct nlattr *attr)
57 if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) {
58 struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1];
60 nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max,
61 attr, l4proto->ctnl_timeout.nla_policy);
63 ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, &timeout->data);
69 cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb,
70 const struct nlmsghdr *nlh,
71 const struct nlattr * const cda[])
75 struct nf_conntrack_l4proto *l4proto;
76 struct ctnl_timeout *timeout, *matching = NULL;
80 if (!cda[CTA_TIMEOUT_NAME] ||
81 !cda[CTA_TIMEOUT_L3PROTO] ||
82 !cda[CTA_TIMEOUT_L4PROTO] ||
83 !cda[CTA_TIMEOUT_DATA])
86 name = nla_data(cda[CTA_TIMEOUT_NAME]);
87 l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
88 l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
90 list_for_each_entry(timeout, &cttimeout_list, head) {
91 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
94 if (nlh->nlmsg_flags & NLM_F_EXCL)
101 l4proto = nf_ct_l4proto_find_get(l3num, l4num);
103 /* This protocol is not supportted, skip. */
104 if (l4proto->l4proto != l4num) {
110 if (nlh->nlmsg_flags & NLM_F_REPLACE) {
111 /* You cannot replace one timeout policy by another of
112 * different kind, sorry.
114 if (matching->l3num != l3num ||
115 matching->l4proto->l4proto != l4num) {
120 ret = ctnl_timeout_parse_policy(matching, l4proto,
121 cda[CTA_TIMEOUT_DATA]);
128 timeout = kzalloc(sizeof(struct ctnl_timeout) +
129 l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
130 if (timeout == NULL) {
135 ret = ctnl_timeout_parse_policy(timeout, l4proto,
136 cda[CTA_TIMEOUT_DATA]);
140 strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME]));
141 timeout->l3num = l3num;
142 timeout->l4proto = l4proto;
143 atomic_set(&timeout->refcnt, 1);
144 list_add_tail_rcu(&timeout->head, &cttimeout_list);
150 nf_ct_l4proto_put(l4proto);
155 ctnl_timeout_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type,
156 int event, struct ctnl_timeout *timeout)
158 struct nlmsghdr *nlh;
159 struct nfgenmsg *nfmsg;
160 unsigned int flags = pid ? NLM_F_MULTI : 0;
161 struct nf_conntrack_l4proto *l4proto = timeout->l4proto;
163 event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8;
164 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*nfmsg), flags);
168 nfmsg = nlmsg_data(nlh);
169 nfmsg->nfgen_family = AF_UNSPEC;
170 nfmsg->version = NFNETLINK_V0;
173 if (nla_put_string(skb, CTA_TIMEOUT_NAME, timeout->name) ||
174 nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num)) ||
175 nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4proto->l4proto) ||
176 nla_put_be32(skb, CTA_TIMEOUT_USE,
177 htonl(atomic_read(&timeout->refcnt))))
178 goto nla_put_failure;
180 if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
181 struct nlattr *nest_parms;
184 nest_parms = nla_nest_start(skb,
185 CTA_TIMEOUT_DATA | NLA_F_NESTED);
187 goto nla_put_failure;
189 ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data);
191 goto nla_put_failure;
193 nla_nest_end(skb, nest_parms);
201 nlmsg_cancel(skb, nlh);
206 ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb)
208 struct ctnl_timeout *cur, *last;
213 last = (struct ctnl_timeout *)cb->args[1];
218 list_for_each_entry_rcu(cur, &cttimeout_list, head) {
219 if (last && cur != last)
222 if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).pid,
224 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
225 IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) {
226 cb->args[1] = (unsigned long)cur;
237 cttimeout_get_timeout(struct sock *ctnl, struct sk_buff *skb,
238 const struct nlmsghdr *nlh,
239 const struct nlattr * const cda[])
243 struct ctnl_timeout *cur;
245 if (nlh->nlmsg_flags & NLM_F_DUMP) {
246 struct netlink_dump_control c = {
247 .dump = ctnl_timeout_dump,
249 return netlink_dump_start(ctnl, skb, nlh, &c);
252 if (!cda[CTA_TIMEOUT_NAME])
254 name = nla_data(cda[CTA_TIMEOUT_NAME]);
256 list_for_each_entry(cur, &cttimeout_list, head) {
257 struct sk_buff *skb2;
259 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
262 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
268 ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).pid,
270 NFNL_MSG_TYPE(nlh->nlmsg_type),
271 IPCTNL_MSG_TIMEOUT_NEW, cur);
276 ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).pid,
281 /* this avoids a loop in nfnetlink. */
282 return ret == -EAGAIN ? -ENOBUFS : ret;
287 /* try to delete object, fail if it is still in use. */
288 static int ctnl_timeout_try_del(struct ctnl_timeout *timeout)
292 /* we want to avoid races with nf_ct_timeout_find_get. */
293 if (atomic_dec_and_test(&timeout->refcnt)) {
294 /* We are protected by nfnl mutex. */
295 list_del_rcu(&timeout->head);
296 nf_ct_l4proto_put(timeout->l4proto);
297 kfree_rcu(timeout, rcu_head);
299 /* still in use, restore reference counter. */
300 atomic_inc(&timeout->refcnt);
307 cttimeout_del_timeout(struct sock *ctnl, struct sk_buff *skb,
308 const struct nlmsghdr *nlh,
309 const struct nlattr * const cda[])
312 struct ctnl_timeout *cur;
315 if (!cda[CTA_TIMEOUT_NAME]) {
316 list_for_each_entry(cur, &cttimeout_list, head)
317 ctnl_timeout_try_del(cur);
321 name = nla_data(cda[CTA_TIMEOUT_NAME]);
323 list_for_each_entry(cur, &cttimeout_list, head) {
324 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
327 ret = ctnl_timeout_try_del(cur);
336 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
337 static struct ctnl_timeout *ctnl_timeout_find_get(const char *name)
339 struct ctnl_timeout *timeout, *matching = NULL;
342 list_for_each_entry_rcu(timeout, &cttimeout_list, head) {
343 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
346 if (!try_module_get(THIS_MODULE))
349 if (!atomic_inc_not_zero(&timeout->refcnt)) {
350 module_put(THIS_MODULE);
361 static void ctnl_timeout_put(struct ctnl_timeout *timeout)
363 atomic_dec(&timeout->refcnt);
364 module_put(THIS_MODULE);
366 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
368 static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
369 [IPCTNL_MSG_TIMEOUT_NEW] = { .call = cttimeout_new_timeout,
370 .attr_count = CTA_TIMEOUT_MAX,
371 .policy = cttimeout_nla_policy },
372 [IPCTNL_MSG_TIMEOUT_GET] = { .call = cttimeout_get_timeout,
373 .attr_count = CTA_TIMEOUT_MAX,
374 .policy = cttimeout_nla_policy },
375 [IPCTNL_MSG_TIMEOUT_DELETE] = { .call = cttimeout_del_timeout,
376 .attr_count = CTA_TIMEOUT_MAX,
377 .policy = cttimeout_nla_policy },
380 static const struct nfnetlink_subsystem cttimeout_subsys = {
381 .name = "conntrack_timeout",
382 .subsys_id = NFNL_SUBSYS_CTNETLINK_TIMEOUT,
383 .cb_count = IPCTNL_MSG_TIMEOUT_MAX,
387 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);
389 static int __init cttimeout_init(void)
393 ret = nfnetlink_subsys_register(&cttimeout_subsys);
395 pr_err("cttimeout_init: cannot register cttimeout with "
399 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
400 RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get);
401 RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put);
402 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
409 static void __exit cttimeout_exit(void)
411 struct ctnl_timeout *cur, *tmp;
413 pr_info("cttimeout: unregistering from nfnetlink.\n");
415 nfnetlink_subsys_unregister(&cttimeout_subsys);
416 list_for_each_entry_safe(cur, tmp, &cttimeout_list, head) {
417 list_del_rcu(&cur->head);
418 /* We are sure that our objects have no clients at this point,
419 * it's safe to release them all without checking refcnt.
421 nf_ct_l4proto_put(cur->l4proto);
422 kfree_rcu(cur, rcu_head);
424 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
425 RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL);
426 RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL);
427 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
430 module_init(cttimeout_init);
431 module_exit(cttimeout_exit);