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 .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 },
52 ctnl_timeout_parse_policy(struct ctnl_timeout *timeout,
53 struct nf_conntrack_l4proto *l4proto,
55 const struct nlattr *attr)
59 if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) {
60 struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1];
62 nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max,
63 attr, l4proto->ctnl_timeout.nla_policy);
65 ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net,
72 cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb,
73 const struct nlmsghdr *nlh,
74 const struct nlattr * const cda[])
78 struct nf_conntrack_l4proto *l4proto;
79 struct ctnl_timeout *timeout, *matching = NULL;
80 struct net *net = sock_net(skb->sk);
84 if (!cda[CTA_TIMEOUT_NAME] ||
85 !cda[CTA_TIMEOUT_L3PROTO] ||
86 !cda[CTA_TIMEOUT_L4PROTO] ||
87 !cda[CTA_TIMEOUT_DATA])
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]);
94 list_for_each_entry(timeout, &cttimeout_list, head) {
95 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
98 if (nlh->nlmsg_flags & NLM_F_EXCL)
105 l4proto = nf_ct_l4proto_find_get(l3num, l4num);
107 /* This protocol is not supportted, skip. */
108 if (l4proto->l4proto != l4num) {
114 if (nlh->nlmsg_flags & NLM_F_REPLACE) {
115 /* You cannot replace one timeout policy by another of
116 * different kind, sorry.
118 if (matching->l3num != l3num ||
119 matching->l4proto->l4proto != l4num) {
124 ret = ctnl_timeout_parse_policy(matching, l4proto, net,
125 cda[CTA_TIMEOUT_DATA]);
132 timeout = kzalloc(sizeof(struct ctnl_timeout) +
133 l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
134 if (timeout == NULL) {
139 ret = ctnl_timeout_parse_policy(timeout, l4proto, net,
140 cda[CTA_TIMEOUT_DATA]);
144 strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME]));
145 timeout->l3num = l3num;
146 timeout->l4proto = l4proto;
147 atomic_set(&timeout->refcnt, 1);
148 list_add_tail_rcu(&timeout->head, &cttimeout_list);
154 nf_ct_l4proto_put(l4proto);
159 ctnl_timeout_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
160 int event, struct ctnl_timeout *timeout)
162 struct nlmsghdr *nlh;
163 struct nfgenmsg *nfmsg;
164 unsigned int flags = portid ? NLM_F_MULTI : 0;
165 struct nf_conntrack_l4proto *l4proto = timeout->l4proto;
167 event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8;
168 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
172 nfmsg = nlmsg_data(nlh);
173 nfmsg->nfgen_family = AF_UNSPEC;
174 nfmsg->version = NFNETLINK_V0;
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;
184 if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
185 struct nlattr *nest_parms;
188 nest_parms = nla_nest_start(skb,
189 CTA_TIMEOUT_DATA | NLA_F_NESTED);
191 goto nla_put_failure;
193 ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data);
195 goto nla_put_failure;
197 nla_nest_end(skb, nest_parms);
205 nlmsg_cancel(skb, nlh);
210 ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb)
212 struct ctnl_timeout *cur, *last;
217 last = (struct ctnl_timeout *)cb->args[1];
222 list_for_each_entry_rcu(cur, &cttimeout_list, head) {
229 if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).portid,
231 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
232 IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) {
233 cb->args[1] = (unsigned long)cur;
244 cttimeout_get_timeout(struct sock *ctnl, struct sk_buff *skb,
245 const struct nlmsghdr *nlh,
246 const struct nlattr * const cda[])
250 struct ctnl_timeout *cur;
252 if (nlh->nlmsg_flags & NLM_F_DUMP) {
253 struct netlink_dump_control c = {
254 .dump = ctnl_timeout_dump,
256 return netlink_dump_start(ctnl, skb, nlh, &c);
259 if (!cda[CTA_TIMEOUT_NAME])
261 name = nla_data(cda[CTA_TIMEOUT_NAME]);
263 list_for_each_entry(cur, &cttimeout_list, head) {
264 struct sk_buff *skb2;
266 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
269 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
275 ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).portid,
277 NFNL_MSG_TYPE(nlh->nlmsg_type),
278 IPCTNL_MSG_TIMEOUT_NEW, cur);
283 ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid,
288 /* this avoids a loop in nfnetlink. */
289 return ret == -EAGAIN ? -ENOBUFS : ret;
294 /* try to delete object, fail if it is still in use. */
295 static int ctnl_timeout_try_del(struct ctnl_timeout *timeout)
299 /* we want to avoid races with nf_ct_timeout_find_get. */
300 if (atomic_dec_and_test(&timeout->refcnt)) {
301 /* We are protected by nfnl mutex. */
302 list_del_rcu(&timeout->head);
303 nf_ct_l4proto_put(timeout->l4proto);
304 kfree_rcu(timeout, rcu_head);
306 /* still in use, restore reference counter. */
307 atomic_inc(&timeout->refcnt);
314 cttimeout_del_timeout(struct sock *ctnl, struct sk_buff *skb,
315 const struct nlmsghdr *nlh,
316 const struct nlattr * const cda[])
319 struct ctnl_timeout *cur;
322 if (!cda[CTA_TIMEOUT_NAME]) {
323 list_for_each_entry(cur, &cttimeout_list, head)
324 ctnl_timeout_try_del(cur);
328 name = nla_data(cda[CTA_TIMEOUT_NAME]);
330 list_for_each_entry(cur, &cttimeout_list, head) {
331 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
334 ret = ctnl_timeout_try_del(cur);
343 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
344 static struct ctnl_timeout *ctnl_timeout_find_get(const char *name)
346 struct ctnl_timeout *timeout, *matching = NULL;
349 list_for_each_entry_rcu(timeout, &cttimeout_list, head) {
350 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
353 if (!try_module_get(THIS_MODULE))
356 if (!atomic_inc_not_zero(&timeout->refcnt)) {
357 module_put(THIS_MODULE);
368 static void ctnl_timeout_put(struct ctnl_timeout *timeout)
370 atomic_dec(&timeout->refcnt);
371 module_put(THIS_MODULE);
373 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
375 static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
376 [IPCTNL_MSG_TIMEOUT_NEW] = { .call = cttimeout_new_timeout,
377 .attr_count = CTA_TIMEOUT_MAX,
378 .policy = cttimeout_nla_policy },
379 [IPCTNL_MSG_TIMEOUT_GET] = { .call = cttimeout_get_timeout,
380 .attr_count = CTA_TIMEOUT_MAX,
381 .policy = cttimeout_nla_policy },
382 [IPCTNL_MSG_TIMEOUT_DELETE] = { .call = cttimeout_del_timeout,
383 .attr_count = CTA_TIMEOUT_MAX,
384 .policy = cttimeout_nla_policy },
387 static const struct nfnetlink_subsystem cttimeout_subsys = {
388 .name = "conntrack_timeout",
389 .subsys_id = NFNL_SUBSYS_CTNETLINK_TIMEOUT,
390 .cb_count = IPCTNL_MSG_TIMEOUT_MAX,
394 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);
396 static int __init cttimeout_init(void)
400 ret = nfnetlink_subsys_register(&cttimeout_subsys);
402 pr_err("cttimeout_init: cannot register cttimeout with "
406 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
407 RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get);
408 RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put);
409 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
416 static void __exit cttimeout_exit(void)
418 struct ctnl_timeout *cur, *tmp;
420 pr_info("cttimeout: unregistering from nfnetlink.\n");
422 nfnetlink_subsys_unregister(&cttimeout_subsys);
423 list_for_each_entry_safe(cur, tmp, &cttimeout_list, head) {
424 list_del_rcu(&cur->head);
425 /* We are sure that our objects have no clients at this point,
426 * it's safe to release them all without checking refcnt.
428 nf_ct_l4proto_put(cur->l4proto);
429 kfree_rcu(cur, rcu_head);
431 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
432 RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL);
433 RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL);
434 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
437 module_init(cttimeout_init);
438 module_exit(cttimeout_exit);