[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 <net/netfilter/nf_conntrack_timeout.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");

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_get(l3num, l4num);

	/* This protocol is not supportted, skip. */
	if (l4proto->l4proto != l4num) {
		ret = -EOPNOTSUPP;
		goto err_proto_put;
	}

	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->l4proto->l4proto != l4num) {
				ret = -EINVAL;
				goto err_proto_put;
			}

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

	timeout = kzalloc(sizeof(struct ctnl_timeout) +
			  l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
	if (timeout == NULL) {
		ret = -ENOMEM;
		goto err_proto_put;
	}

	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->l4proto = l4proto;
	atomic_set(&timeout->refcnt, 1);
	list_add_tail_rcu(&timeout->head, &cttimeout_list);

	return 0;
err:
	kfree(timeout);
err_proto_put:
	nf_ct_l4proto_put(l4proto);
	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 = timeout->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->l4proto->l4proto);
	NLA_PUT_BE32(skb, CTA_TIMEOUT_USE,
			htonl(atomic_read(&timeout->refcnt)));

	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);
	}

	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);
		nf_ct_l4proto_put(timeout->l4proto);
		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;
}

#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
static struct ctnl_timeout *ctnl_timeout_find_get(const char *name)
{
	struct ctnl_timeout *timeout, *matching = NULL;

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

		if (!try_module_get(THIS_MODULE))
			goto err;

		if (!atomic_inc_not_zero(&timeout->refcnt)) {
			module_put(THIS_MODULE);
			goto err;
		}
		matching = timeout;
		break;
	}
err:
	rcu_read_unlock();
	return matching;
}

static void ctnl_timeout_put(struct ctnl_timeout *timeout)
{
	atomic_dec(&timeout->refcnt);
	module_put(THIS_MODULE);
}
#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */

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;
	}
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
	RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get);
	RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put);
#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
	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.
		 */
		nf_ct_l4proto_put(cur->l4proto);
		kfree_rcu(cur, rcu_head);
	}
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
	RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL);
	RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL);
#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
}

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>
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] = {
	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 },
	48	};
	49
	50	static int
	51	ctnl_timeout_parse_policy(struct ctnl_timeout *timeout,
	52	struct nf_conntrack_l4proto *l4proto,
	53	const struct nlattr *attr)
	54	{
	55	int ret = 0;
	56
	57	if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) {
	58	struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1];
	59
	60	nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max,
	61	attr, l4proto->ctnl_timeout.nla_policy);
	62
	63	ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, &timeout->data);
	64	}
	65	return ret;
	66	}
	67
	68	static int
	69	cttimeout_new_timeout(struct sock ctnl, struct sk_buff skb,
	70	const struct nlmsghdr *nlh,
	71	const struct nlattr * const cda[])
	72	{
	73	__u16 l3num;
	74	__u8 l4num;
	75	struct nf_conntrack_l4proto *l4proto;
	76	struct ctnl_timeout timeout, matching = NULL;
	77	char *name;
	78	int ret;
	79
	80	if (!cda[CTA_TIMEOUT_NAME] \|\|
	81	!cda[CTA_TIMEOUT_L3PROTO] \|\|
	82	!cda[CTA_TIMEOUT_L4PROTO] \|\|
	83	!cda[CTA_TIMEOUT_DATA])
	84	return -EINVAL;
	85
	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]);
	89
	90	list_for_each_entry(timeout, &cttimeout_list, head) {
	91	if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
	92	continue;
	93
	94	if (nlh->nlmsg_flags & NLM_F_EXCL)
	95	return -EEXIST;
	96
	97	matching = timeout;
	98	break;
	99	}
	100
c1ebd7df	101	l4proto = nf_ct_l4proto_find_get(l3num, l4num);
50978462 PNA	102
50978462 PNA	103	/* This protocol is not supportted, skip. */
c1ebd7df PNA	104	if (l4proto->l4proto != l4num) {
	105	ret = -EOPNOTSUPP;
	106	goto err_proto_put;
	107	}
50978462 PNA	108
	109	if (matching) {
	110	if (nlh->nlmsg_flags & NLM_F_REPLACE) {
	111	/* You cannot replace one timeout policy by another of
	112	* different kind, sorry.
	113	*/
	114	if (matching->l3num != l3num \|\|
c1ebd7df PNA	115	matching->l4proto->l4proto != l4num) {
	116	ret = -EINVAL;
	117	goto err_proto_put;
	118	}
50978462 PNA	119
	120	ret = ctnl_timeout_parse_policy(matching, l4proto,
	121	cda[CTA_TIMEOUT_DATA]);
	122	return ret;
	123	}
c1ebd7df PNA	124	ret = -EBUSY;
c1ebd7df PNA	125	goto err_proto_put;
50978462 PNA	126	}
	127
	128	timeout = kzalloc(sizeof(struct ctnl_timeout) +
	129	l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
c1ebd7df PNA	130	if (timeout == NULL) {
	131	ret = -ENOMEM;
	132	goto err_proto_put;
	133	}
50978462 PNA	134
	135	ret = ctnl_timeout_parse_policy(timeout, l4proto,
	136	cda[CTA_TIMEOUT_DATA]);
	137	if (ret < 0)
	138	goto err;
	139
	140	strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME]));
	141	timeout->l3num = l3num;
c1ebd7df	142	timeout->l4proto = l4proto;
50978462 PNA	143	atomic_set(&timeout->refcnt, 1);
	144	list_add_tail_rcu(&timeout->head, &cttimeout_list);
	145
	146	return 0;
	147	err:
	148	kfree(timeout);
c1ebd7df PNA	149	err_proto_put:
c1ebd7df PNA	150	nf_ct_l4proto_put(l4proto);
50978462 PNA	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;
c1ebd7df	161	struct nf_conntrack_l4proto *l4proto = timeout->l4proto;
50978462 PNA	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));
c1ebd7df	175	NLA_PUT_U8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4proto->l4proto);
50978462 PNA	176	NLA_PUT_BE32(skb, CTA_TIMEOUT_USE,
	177	htonl(atomic_read(&timeout->refcnt)));
	178
50978462 PNA	179	if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
	180	struct nlattr *nest_parms;
	181	int ret;
	182
	183	nest_parms = nla_nest_start(skb,
	184	CTA_TIMEOUT_DATA \| NLA_F_NESTED);
	185	if (!nest_parms)
	186	goto nla_put_failure;
	187
	188	ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data);
	189	if (ret < 0)
	190	goto nla_put_failure;
	191
	192	nla_nest_end(skb, nest_parms);
	193	}
c1ebd7df	194
50978462 PNA	195	nlmsg_end(skb, nlh);
	196	return skb->len;
	197
	198	nlmsg_failure:
	199	nla_put_failure:
	200	nlmsg_cancel(skb, nlh);
	201	return -1;
	202	}
	203
	204	static int
	205	ctnl_timeout_dump(struct sk_buff skb, struct netlink_callback cb)
	206	{
	207	struct ctnl_timeout cur, last;
	208
	209	if (cb->args[2])
	210	return 0;
	211
	212	last = (struct ctnl_timeout *)cb->args[1];
	213	if (cb->args[1])
	214	cb->args[1] = 0;
	215
	216	rcu_read_lock();
	217	list_for_each_entry_rcu(cur, &cttimeout_list, head) {
	218	if (last && cur != last)
	219	continue;
	220
	221	if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).pid,
	222	cb->nlh->nlmsg_seq,
	223	NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
	224	IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) {
	225	cb->args[1] = (unsigned long)cur;
	226	break;
	227	}
	228	}
	229	if (!cb->args[1])
	230	cb->args[2] = 1;
	231	rcu_read_unlock();
	232	return skb->len;
	233	}
	234
	235	static int
	236	cttimeout_get_timeout(struct sock ctnl, struct sk_buff skb,
	237	const struct nlmsghdr *nlh,
	238	const struct nlattr * const cda[])
	239	{
	240	int ret = -ENOENT;
	241	char *name;
	242	struct ctnl_timeout *cur;
	243
	244	if (nlh->nlmsg_flags & NLM_F_DUMP) {
	245	struct netlink_dump_control c = {
	246	.dump = ctnl_timeout_dump,
	247	};
	248	return netlink_dump_start(ctnl, skb, nlh, &c);
	249	}
	250
	251	if (!cda[CTA_TIMEOUT_NAME])
	252	return -EINVAL;
	253	name = nla_data(cda[CTA_TIMEOUT_NAME]);
	254
	255	list_for_each_entry(cur, &cttimeout_list, head) {
	256	struct sk_buff *skb2;
	257
	258	if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
259	continue;
260
261	skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
262	if (skb2 == NULL) {
263	ret = -ENOMEM;
264	break;
265	}
266
267	ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).pid,
268	nlh->nlmsg_seq,
269	NFNL_MSG_TYPE(nlh->nlmsg_type),
270	IPCTNL_MSG_TIMEOUT_NEW, cur);
271	if (ret <= 0) {
272	kfree_skb(skb2);
273	break;
274	}
275	ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).pid,
276	MSG_DONTWAIT);
277	if (ret > 0)
278	ret = 0;
279
280	/* this avoids a loop in nfnetlink. */
281	return ret == -EAGAIN ? -ENOBUFS : ret;
282	}
283	return ret;
284	}
285
286	/* try to delete object, fail if it is still in use. */
287	static int ctnl_timeout_try_del(struct ctnl_timeout *timeout)
288	{
289	int ret = 0;
290
291	/* we want to avoid races with nf_ct_timeout_find_get. */
292	if (atomic_dec_and_test(&timeout->refcnt)) {
293	/* We are protected by nfnl mutex. */
294	list_del_rcu(&timeout->head);
c1ebd7df	295	nf_ct_l4proto_put(timeout->l4proto);
50978462 PNA	296	kfree_rcu(timeout, rcu_head);
	297	} else {
	298	/* still in use, restore reference counter. */
	299	atomic_inc(&timeout->refcnt);
	300	ret = -EBUSY;
	301	}
	302	return ret;
	303	}
	304
	305	static int
	306	cttimeout_del_timeout(struct sock ctnl, struct sk_buff skb,
	307	const struct nlmsghdr *nlh,
	308	const struct nlattr * const cda[])
	309	{
	310	char *name;
	311	struct ctnl_timeout *cur;
	312	int ret = -ENOENT;
	313
	314	if (!cda[CTA_TIMEOUT_NAME]) {
	315	list_for_each_entry(cur, &cttimeout_list, head)
	316	ctnl_timeout_try_del(cur);
	317
	318	return 0;
	319	}
	320	name = nla_data(cda[CTA_TIMEOUT_NAME]);
	321
	322	list_for_each_entry(cur, &cttimeout_list, head) {
	323	if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
	324	continue;
	325
	326	ret = ctnl_timeout_try_del(cur);
	327	if (ret < 0)
	328	return ret;
	329
	330	break;
	331	}
	332	return ret;
	333	}
	334
24de58f4 PNA	335	#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
	336	static struct ctnl_timeout ctnl_timeout_find_get(const char name)
	337	{
	338	struct ctnl_timeout timeout, matching = NULL;
	339
	340	rcu_read_lock();
	341	list_for_each_entry_rcu(timeout, &cttimeout_list, head) {
	342	if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
	343	continue;
	344
	345	if (!try_module_get(THIS_MODULE))
	346	goto err;
	347
	348	if (!atomic_inc_not_zero(&timeout->refcnt)) {
	349	module_put(THIS_MODULE);
	350	goto err;
	351	}
	352	matching = timeout;
	353	break;
	354	}
	355	err:
	356	rcu_read_unlock();
	357	return matching;
	358	}
	359
	360	static void ctnl_timeout_put(struct ctnl_timeout *timeout)
	361	{
	362	atomic_dec(&timeout->refcnt);
	363	module_put(THIS_MODULE);
	364	}
	365	#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
	366
50978462 PNA	367	static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
	368	[IPCTNL_MSG_TIMEOUT_NEW] = { .call = cttimeout_new_timeout,
	369	.attr_count = CTA_TIMEOUT_MAX,
	370	.policy = cttimeout_nla_policy },
	371	[IPCTNL_MSG_TIMEOUT_GET] = { .call = cttimeout_get_timeout,
	372	.attr_count = CTA_TIMEOUT_MAX,
	373	.policy = cttimeout_nla_policy },
	374	[IPCTNL_MSG_TIMEOUT_DELETE] = { .call = cttimeout_del_timeout,
	375	.attr_count = CTA_TIMEOUT_MAX,
	376	.policy = cttimeout_nla_policy },
	377	};
	378
	379	static const struct nfnetlink_subsystem cttimeout_subsys = {
	380	.name = "conntrack_timeout",
	381	.subsys_id = NFNL_SUBSYS_CTNETLINK_TIMEOUT,
	382	.cb_count = IPCTNL_MSG_TIMEOUT_MAX,
	383	.cb = cttimeout_cb,
	384	};
	385
	386	MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);
	387
	388	static int __init cttimeout_init(void)
	389	{
	390	int ret;
	391
	392	ret = nfnetlink_subsys_register(&cttimeout_subsys);
	393	if (ret < 0) {
	394	pr_err("cttimeout_init: cannot register cttimeout with "
	395	"nfnetlink.\n");
	396	goto err_out;
	397	}
24de58f4 PNA	398	#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
	399	RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get);
	400	RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put);
	401	#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
50978462 PNA	402	return 0;
	403
	404	err_out:
	405	return ret;
	406	}
	407
	408	static void __exit cttimeout_exit(void)
	409	{
	410	struct ctnl_timeout cur, tmp;
	411
	412	pr_info("cttimeout: unregistering from nfnetlink.\n");
	413
	414	nfnetlink_subsys_unregister(&cttimeout_subsys);
	415	list_for_each_entry_safe(cur, tmp, &cttimeout_list, head) {
	416	list_del_rcu(&cur->head);
	417	/* We are sure that our objects have no clients at this point,
	418	* it's safe to release them all without checking refcnt.
	419	*/
c1ebd7df	420	nf_ct_l4proto_put(cur->l4proto);
50978462 PNA	421	kfree_rcu(cur, rcu_head);
50978462 PNA	422	}
24de58f4 PNA	423	#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
	424	RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL);
	425	RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL);
	426	#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
50978462 PNA	427	}
	428
	429	module_init(cttimeout_init);
	430	module_exit(cttimeout_exit);