[deliverable/linux.git] / net / netfilter / nfnetlink_cttimeout.c

/*
 * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
 * (C) 2012 by Vyatta Inc. <http://www.vyatta.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation (or any later at your option).
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/rculist.h>
#include <linux/rculist_nulls.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/security.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/netlink.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/slab.h>

#include <linux/netfilter.h>
#include <net/netlink.h>
#include <net/sock.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_tuple.h>

#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_cttimeout.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tuning");

struct ctnl_timeout {
	struct list_head	head;
	struct rcu_head		rcu_head;
	atomic_t		refcnt;
	char			name[CTNL_TIMEOUT_NAME_MAX];
	__u16			l3num;
	__u8			l4num;
	char			data[0];
};

static LIST_HEAD(cttimeout_list);

static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = {
	[CTA_TIMEOUT_NAME]	= { .type = NLA_NUL_STRING },
	[CTA_TIMEOUT_L3PROTO]	= { .type = NLA_U16 },
	[CTA_TIMEOUT_L4PROTO]	= { .type = NLA_U8 },
	[CTA_TIMEOUT_DATA]	= { .type = NLA_NESTED },
};

static int
ctnl_timeout_parse_policy(struct ctnl_timeout *timeout,
			       struct nf_conntrack_l4proto *l4proto,
			       const struct nlattr *attr)
{
	int ret = 0;

	if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) {
		struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1];

		nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max,
				 attr, l4proto->ctnl_timeout.nla_policy);

		ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, &timeout->data);
	}
	return ret;
}

static int
cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb,
		      const struct nlmsghdr *nlh,
		      const struct nlattr * const cda[])
{
	__u16 l3num;
	__u8 l4num;
	struct nf_conntrack_l4proto *l4proto;
	struct ctnl_timeout *timeout, *matching = NULL;
	char *name;
	int ret;

	if (!cda[CTA_TIMEOUT_NAME] ||
	    !cda[CTA_TIMEOUT_L3PROTO] ||
	    !cda[CTA_TIMEOUT_L4PROTO] ||
	    !cda[CTA_TIMEOUT_DATA])
		return -EINVAL;

	name = nla_data(cda[CTA_TIMEOUT_NAME]);
	l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
	l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);

	list_for_each_entry(timeout, &cttimeout_list, head) {
		if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
			continue;

		if (nlh->nlmsg_flags & NLM_F_EXCL)
			return -EEXIST;

		matching = timeout;
		break;
	}

	l4proto = __nf_ct_l4proto_find(l3num, l4num);

	/* This protocol is not supportted, skip. */
	if (l4proto->l4proto != l4num)
		return -EOPNOTSUPP;

	if (matching) {
		if (nlh->nlmsg_flags & NLM_F_REPLACE) {
			/* You cannot replace one timeout policy by another of
			 * different kind, sorry.
			 */
			if (matching->l3num != l3num ||
			    matching->l4num != l4num)
				return -EINVAL;

			ret = ctnl_timeout_parse_policy(matching, l4proto,
							cda[CTA_TIMEOUT_DATA]);
			return ret;
		}
		return -EBUSY;
	}

	timeout = kzalloc(sizeof(struct ctnl_timeout) +
			  l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
	if (timeout == NULL)
		return -ENOMEM;

	ret = ctnl_timeout_parse_policy(timeout, l4proto,
					cda[CTA_TIMEOUT_DATA]);
	if (ret < 0)
		goto err;

	strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME]));
	timeout->l3num = l3num;
	timeout->l4num = l4num;
	atomic_set(&timeout->refcnt, 1);
	list_add_tail_rcu(&timeout->head, &cttimeout_list);

	return 0;
err:
	kfree(timeout);
	return ret;
}

static int
ctnl_timeout_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type,
		       int event, struct ctnl_timeout *timeout)
{
	struct nlmsghdr *nlh;
	struct nfgenmsg *nfmsg;
	unsigned int flags = pid ? NLM_F_MULTI : 0;
	struct nf_conntrack_l4proto *l4proto;

	event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8;
	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*nfmsg), flags);
	if (nlh == NULL)
		goto nlmsg_failure;

	nfmsg = nlmsg_data(nlh);
	nfmsg->nfgen_family = AF_UNSPEC;
	nfmsg->version = NFNETLINK_V0;
	nfmsg->res_id = 0;

	NLA_PUT_STRING(skb, CTA_TIMEOUT_NAME, timeout->name);
	NLA_PUT_BE16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num));
	NLA_PUT_U8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4num);
	NLA_PUT_BE32(skb, CTA_TIMEOUT_USE,
			htonl(atomic_read(&timeout->refcnt)));

	l4proto = __nf_ct_l4proto_find(timeout->l3num, timeout->l4num);

	/* If the timeout object does not match the layer 4 protocol tracker,
	 * then skip dumping the data part since we don't know how to
	 * interpret it. This may happen for UPDlite, SCTP and DCCP since
	 * you can unload the module.
	 */
	if (timeout->l4num != l4proto->l4proto)
		goto out;

	if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
		struct nlattr *nest_parms;
		int ret;

		nest_parms = nla_nest_start(skb,
					    CTA_TIMEOUT_DATA | NLA_F_NESTED);
		if (!nest_parms)
			goto nla_put_failure;

		ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data);
		if (ret < 0)
			goto nla_put_failure;

		nla_nest_end(skb, nest_parms);
	}
out:
	nlmsg_end(skb, nlh);
	return skb->len;

nlmsg_failure:
nla_put_failure:
	nlmsg_cancel(skb, nlh);
	return -1;
}

static int
ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct ctnl_timeout *cur, *last;

	if (cb->args[2])
		return 0;

	last = (struct ctnl_timeout *)cb->args[1];
	if (cb->args[1])
		cb->args[1] = 0;

	rcu_read_lock();
	list_for_each_entry_rcu(cur, &cttimeout_list, head) {
		if (last && cur != last)
			continue;

		if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).pid,
					   cb->nlh->nlmsg_seq,
					   NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
					   IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) {
			cb->args[1] = (unsigned long)cur;
			break;
		}
	}
	if (!cb->args[1])
		cb->args[2] = 1;
	rcu_read_unlock();
	return skb->len;
}

static int
cttimeout_get_timeout(struct sock *ctnl, struct sk_buff *skb,
		      const struct nlmsghdr *nlh,
		      const struct nlattr * const cda[])
{
	int ret = -ENOENT;
	char *name;
	struct ctnl_timeout *cur;

	if (nlh->nlmsg_flags & NLM_F_DUMP) {
		struct netlink_dump_control c = {
			.dump = ctnl_timeout_dump,
		};
		return netlink_dump_start(ctnl, skb, nlh, &c);
	}

	if (!cda[CTA_TIMEOUT_NAME])
		return -EINVAL;
	name = nla_data(cda[CTA_TIMEOUT_NAME]);

	list_for_each_entry(cur, &cttimeout_list, head) {
		struct sk_buff *skb2;

		if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
			continue;

		skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
		if (skb2 == NULL) {
			ret = -ENOMEM;
			break;
		}

		ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).pid,
					     nlh->nlmsg_seq,
					     NFNL_MSG_TYPE(nlh->nlmsg_type),
					     IPCTNL_MSG_TIMEOUT_NEW, cur);
		if (ret <= 0) {
			kfree_skb(skb2);
			break;
		}
		ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).pid,
					MSG_DONTWAIT);
		if (ret > 0)
			ret = 0;

		/* this avoids a loop in nfnetlink. */
		return ret == -EAGAIN ? -ENOBUFS : ret;
	}
	return ret;
}

/* try to delete object, fail if it is still in use. */
static int ctnl_timeout_try_del(struct ctnl_timeout *timeout)
{
	int ret = 0;

	/* we want to avoid races with nf_ct_timeout_find_get. */
	if (atomic_dec_and_test(&timeout->refcnt)) {
		/* We are protected by nfnl mutex. */
		list_del_rcu(&timeout->head);
		kfree_rcu(timeout, rcu_head);
	} else {
		/* still in use, restore reference counter. */
		atomic_inc(&timeout->refcnt);
		ret = -EBUSY;
	}
	return ret;
}

static int
cttimeout_del_timeout(struct sock *ctnl, struct sk_buff *skb,
		      const struct nlmsghdr *nlh,
		      const struct nlattr * const cda[])
{
	char *name;
	struct ctnl_timeout *cur;
	int ret = -ENOENT;

	if (!cda[CTA_TIMEOUT_NAME]) {
		list_for_each_entry(cur, &cttimeout_list, head)
			ctnl_timeout_try_del(cur);

		return 0;
	}
	name = nla_data(cda[CTA_TIMEOUT_NAME]);

	list_for_each_entry(cur, &cttimeout_list, head) {
		if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
			continue;

		ret = ctnl_timeout_try_del(cur);
		if (ret < 0)
			return ret;

		break;
	}
	return ret;
}

static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
	[IPCTNL_MSG_TIMEOUT_NEW]	= { .call = cttimeout_new_timeout,
					    .attr_count = CTA_TIMEOUT_MAX,
					    .policy = cttimeout_nla_policy },
	[IPCTNL_MSG_TIMEOUT_GET]	= { .call = cttimeout_get_timeout,
					    .attr_count = CTA_TIMEOUT_MAX,
					    .policy = cttimeout_nla_policy },
	[IPCTNL_MSG_TIMEOUT_DELETE]	= { .call = cttimeout_del_timeout,
					    .attr_count = CTA_TIMEOUT_MAX,
					    .policy = cttimeout_nla_policy },
};

static const struct nfnetlink_subsystem cttimeout_subsys = {
	.name				= "conntrack_timeout",
	.subsys_id			= NFNL_SUBSYS_CTNETLINK_TIMEOUT,
	.cb_count			= IPCTNL_MSG_TIMEOUT_MAX,
	.cb				= cttimeout_cb,
};

MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);

static int __init cttimeout_init(void)
{
	int ret;

	ret = nfnetlink_subsys_register(&cttimeout_subsys);
	if (ret < 0) {
		pr_err("cttimeout_init: cannot register cttimeout with "
			"nfnetlink.\n");
		goto err_out;
	}
	return 0;

err_out:
	return ret;
}

static void __exit cttimeout_exit(void)
{
	struct ctnl_timeout *cur, *tmp;

	pr_info("cttimeout: unregistering from nfnetlink.\n");

	nfnetlink_subsys_unregister(&cttimeout_subsys);
	list_for_each_entry_safe(cur, tmp, &cttimeout_list, head) {
		list_del_rcu(&cur->head);
		/* We are sure that our objects have no clients at this point,
		 * it's safe to release them all without checking refcnt.
		 */
		kfree_rcu(cur, rcu_head);
	}
}

module_init(cttimeout_init);
module_exit(cttimeout_exit);
Commit	Line	Data
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>
	32
	33	#include <linux/netfilter/nfnetlink.h>
	34	#include <linux/netfilter/nfnetlink_cttimeout.h>
	35
	36	MODULE_LICENSE("GPL");
	37	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
	38	MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tuning");
	39
	40	struct ctnl_timeout {
	41	struct list_head head;
	42	struct rcu_head rcu_head;
	43	atomic_t refcnt;
	44	char name[CTNL_TIMEOUT_NAME_MAX];
	45	__u16 l3num;
	46	__u8 l4num;
	47	char data[0];
	48	};
	49
	50	static LIST_HEAD(cttimeout_list);
	51
	52	static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = {
	53	[CTA_TIMEOUT_NAME] = { .type = NLA_NUL_STRING },
	54	[CTA_TIMEOUT_L3PROTO] = { .type = NLA_U16 },
	55	[CTA_TIMEOUT_L4PROTO] = { .type = NLA_U8 },
	56	[CTA_TIMEOUT_DATA] = { .type = NLA_NESTED },
	57	};
	58
	59	static int
	60	ctnl_timeout_parse_policy(struct ctnl_timeout *timeout,
	61	struct nf_conntrack_l4proto *l4proto,
	62	const struct nlattr *attr)
	63	{
	64	int ret = 0;
65
66	if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) {
67	struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1];
68
69	nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max,
70	attr, l4proto->ctnl_timeout.nla_policy);
71
72	ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, &timeout->data);
73	}
74	return ret;
75	}
76
77	static int
78	cttimeout_new_timeout(struct sock ctnl, struct sk_buff skb,
79	const struct nlmsghdr *nlh,
80	const struct nlattr * const cda[])
81	{
82	__u16 l3num;
83	__u8 l4num;
84	struct nf_conntrack_l4proto *l4proto;
85	struct ctnl_timeout timeout, matching = NULL;
86	char *name;
87	int ret;
88
89	if (!cda[CTA_TIMEOUT_NAME] \|\|
90	!cda[CTA_TIMEOUT_L3PROTO] \|\|
91	!cda[CTA_TIMEOUT_L4PROTO] \|\|
92	!cda[CTA_TIMEOUT_DATA])
93	return -EINVAL;
94
95	name = nla_data(cda[CTA_TIMEOUT_NAME]);
96	l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
97	l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
98
99	list_for_each_entry(timeout, &cttimeout_list, head) {
100	if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
101	continue;
102
103	if (nlh->nlmsg_flags & NLM_F_EXCL)
104	return -EEXIST;
105
106	matching = timeout;
107	break;
108	}
109
110	l4proto = __nf_ct_l4proto_find(l3num, l4num);
111
112	/* This protocol is not supportted, skip. */
113	if (l4proto->l4proto != l4num)
114	return -EOPNOTSUPP;
115
116	if (matching) {
117	if (nlh->nlmsg_flags & NLM_F_REPLACE) {
118	/* You cannot replace one timeout policy by another of
119	* different kind, sorry.
120	*/
121	if (matching->l3num != l3num \|\|
122	matching->l4num != l4num)
123	return -EINVAL;
124
125	ret = ctnl_timeout_parse_policy(matching, l4proto,
126	cda[CTA_TIMEOUT_DATA]);
127	return ret;
128	}
129	return -EBUSY;
130	}
131
132	timeout = kzalloc(sizeof(struct ctnl_timeout) +
133	l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
134	if (timeout == NULL)
135	return -ENOMEM;
136
137	ret = ctnl_timeout_parse_policy(timeout, l4proto,
138	cda[CTA_TIMEOUT_DATA]);
139	if (ret < 0)
140	goto err;
141
142	strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME]));
143	timeout->l3num = l3num;
144	timeout->l4num = l4num;
145	atomic_set(&timeout->refcnt, 1);
146	list_add_tail_rcu(&timeout->head, &cttimeout_list);
147
148	return 0;
149	err:
150	kfree(timeout);
151	return ret;
152	}
153
154	static int
155	ctnl_timeout_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type,
156	int event, struct ctnl_timeout *timeout)
157	{
158	struct nlmsghdr *nlh;
159	struct nfgenmsg *nfmsg;
160	unsigned int flags = pid ? NLM_F_MULTI : 0;
161	struct nf_conntrack_l4proto *l4proto;
162
163	event \|= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8;
164	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*nfmsg), flags);
165	if (nlh == NULL)
166	goto nlmsg_failure;
167
168	nfmsg = nlmsg_data(nlh);
169	nfmsg->nfgen_family = AF_UNSPEC;
170	nfmsg->version = NFNETLINK_V0;
171	nfmsg->res_id = 0;
172
173	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->l4num);
176	NLA_PUT_BE32(skb, CTA_TIMEOUT_USE,
177	htonl(atomic_read(&timeout->refcnt)));
178
179	l4proto = __nf_ct_l4proto_find(timeout->l3num, timeout->l4num);
180
181	/* If the timeout object does not match the layer 4 protocol tracker,
182	* then skip dumping the data part since we don't know how to
183	* interpret it. This may happen for UPDlite, SCTP and DCCP since
184	* you can unload the module.
185	*/
186	if (timeout->l4num != l4proto->l4proto)
187	goto out;
188
189	if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
190	struct nlattr *nest_parms;
191	int ret;
192
193	nest_parms = nla_nest_start(skb,
194	CTA_TIMEOUT_DATA \| NLA_F_NESTED);
195	if (!nest_parms)
196	goto nla_put_failure;
197
198	ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data);
199	if (ret < 0)
200	goto nla_put_failure;
201
202	nla_nest_end(skb, nest_parms);
203	}
204	out:
205	nlmsg_end(skb, nlh);
206	return skb->len;
207
208	nlmsg_failure:
209	nla_put_failure:
210	nlmsg_cancel(skb, nlh);
211	return -1;
212	}
213
214	static int
215	ctnl_timeout_dump(struct sk_buff skb, struct netlink_callback cb)
216	{
217	struct ctnl_timeout cur, last;
218
219	if (cb->args[2])
220	return 0;
221
222	last = (struct ctnl_timeout *)cb->args[1];
223	if (cb->args[1])
224	cb->args[1] = 0;
225
226	rcu_read_lock();
227	list_for_each_entry_rcu(cur, &cttimeout_list, head) {
228	if (last && cur != last)
229	continue;
230
231	if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).pid,
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
245	static int
246	cttimeout_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).pid,
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).pid,
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. */
297	static 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	kfree_rcu(timeout, rcu_head);
306	} else {
307	/* still in use, restore reference counter. */
308	atomic_inc(&timeout->refcnt);
309	ret = -EBUSY;
310	}
311	return ret;
312	}
313
314	static int
315	cttimeout_del_timeout(struct sock ctnl, struct sk_buff skb,
316	const struct nlmsghdr *nlh,
317	const struct nlattr * const cda[])
318	{
319	char *name;
320	struct ctnl_timeout *cur;
321	int ret = -ENOENT;
322
323	if (!cda[CTA_TIMEOUT_NAME]) {
324	list_for_each_entry(cur, &cttimeout_list, head)
325	ctnl_timeout_try_del(cur);
326
327	return 0;
328	}
329	name = nla_data(cda[CTA_TIMEOUT_NAME]);
330
331	list_for_each_entry(cur, &cttimeout_list, head) {
332	if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
333	continue;
334
335	ret = ctnl_timeout_try_del(cur);
336	if (ret < 0)
337	return ret;
338
339	break;
340	}
341	return ret;
342	}
343
344	static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
345	[IPCTNL_MSG_TIMEOUT_NEW] = { .call = cttimeout_new_timeout,
346	.attr_count = CTA_TIMEOUT_MAX,
347	.policy = cttimeout_nla_policy },
348	[IPCTNL_MSG_TIMEOUT_GET] = { .call = cttimeout_get_timeout,
349	.attr_count = CTA_TIMEOUT_MAX,
350	.policy = cttimeout_nla_policy },
351	[IPCTNL_MSG_TIMEOUT_DELETE] = { .call = cttimeout_del_timeout,
352	.attr_count = CTA_TIMEOUT_MAX,
353	.policy = cttimeout_nla_policy },
354	};
355
356	static const struct nfnetlink_subsystem cttimeout_subsys = {
357	.name = "conntrack_timeout",
358	.subsys_id = NFNL_SUBSYS_CTNETLINK_TIMEOUT,
359	.cb_count = IPCTNL_MSG_TIMEOUT_MAX,
360	.cb = cttimeout_cb,
361	};
362
363	MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);
364
365	static int __init cttimeout_init(void)
366	{
367	int ret;
368
369	ret = nfnetlink_subsys_register(&cttimeout_subsys);
370	if (ret < 0) {
371	pr_err("cttimeout_init: cannot register cttimeout with "
372	"nfnetlink.\n");
373	goto err_out;
374	}
375	return 0;
376
377	err_out:
378	return ret;
379	}
380
381	static void __exit cttimeout_exit(void)
382	{
383	struct ctnl_timeout cur, tmp;
384
385	pr_info("cttimeout: unregistering from nfnetlink.\n");
386
387	nfnetlink_subsys_unregister(&cttimeout_subsys);
388	list_for_each_entry_safe(cur, tmp, &cttimeout_list, head) {
389	list_del_rcu(&cur->head);
390	/* We are sure that our objects have no clients at this point,
391	* it's safe to release them all without checking refcnt.
392	*/
393	kfree_rcu(cur, rcu_head);
394	}
395	}
396
397	module_init(cttimeout_init);
398	module_exit(cttimeout_exit);