[linux-2.6-block.git] / net / netfilter / nfnetlink_cthelper.c

/*
 * (C) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
 *
 * 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).
 *
 * This software has been sponsored by Vyatta Inc. <http://www.vyatta.com>
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/rculist.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <net/netlink.h>
#include <net/sock.h>

#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_ecache.h>

#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
#include <linux/netfilter/nfnetlink_cthelper.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers");

static int
nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
			struct nf_conn *ct, enum ip_conntrack_info ctinfo)
{
	const struct nf_conn_help *help;
	struct nf_conntrack_helper *helper;

	help = nfct_help(ct);
	if (help == NULL)
		return NF_DROP;

	/* rcu_read_lock()ed by nf_hook_slow */
	helper = rcu_dereference(help->helper);
	if (helper == NULL)
		return NF_DROP;

	/* This is an user-space helper not yet configured, skip. */
	if ((helper->flags &
	    (NF_CT_HELPER_F_USERSPACE | NF_CT_HELPER_F_CONFIGURED)) ==
	     NF_CT_HELPER_F_USERSPACE)
		return NF_ACCEPT;

	/* If the user-space helper is not available, don't block traffic. */
	return NF_QUEUE_NR(helper->queue_num) | NF_VERDICT_FLAG_QUEUE_BYPASS;
}

static const struct nla_policy nfnl_cthelper_tuple_pol[NFCTH_TUPLE_MAX+1] = {
	[NFCTH_TUPLE_L3PROTONUM] = { .type = NLA_U16, },
	[NFCTH_TUPLE_L4PROTONUM] = { .type = NLA_U8, },
};

static int
nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
			  const struct nlattr *attr)
{
	int err;
	struct nlattr *tb[NFCTH_TUPLE_MAX+1];

	err = nla_parse_nested(tb, NFCTH_TUPLE_MAX, attr, nfnl_cthelper_tuple_pol);
	if (err < 0)
		return err;

	if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
		return -EINVAL;

	tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
	tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);

	return 0;
}

static int
nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
{
	struct nf_conn_help *help = nfct_help(ct);

	if (attr == NULL)
		return -EINVAL;

	if (help->helper->data_len == 0)
		return -EINVAL;

	memcpy(help->data, nla_data(attr), help->helper->data_len);
	return 0;
}

static int
nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
{
	const struct nf_conn_help *help = nfct_help(ct);

	if (help->helper->data_len &&
	    nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
		goto nla_put_failure;

	return 0;

nla_put_failure:
	return -ENOSPC;
}

static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
	[NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
				.len = NF_CT_HELPER_NAME_LEN-1 },
	[NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
	[NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
};

static int
nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
			    const struct nlattr *attr)
{
	int err;
	struct nlattr *tb[NFCTH_POLICY_MAX+1];

	err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr, nfnl_cthelper_expect_pol);
	if (err < 0)
		return err;

	if (!tb[NFCTH_POLICY_NAME] ||
	    !tb[NFCTH_POLICY_EXPECT_MAX] ||
	    !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
		return -EINVAL;

	strncpy(expect_policy->name,
		nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
	expect_policy->max_expected =
		ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
	expect_policy->timeout =
		ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));

	return 0;
}

static const struct nla_policy
nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
	[NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
};

static int
nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
				  const struct nlattr *attr)
{
	int i, ret;
	struct nf_conntrack_expect_policy *expect_policy;
	struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];

	ret = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
			       nfnl_cthelper_expect_policy_set);
	if (ret < 0)
		return ret;

	if (!tb[NFCTH_POLICY_SET_NUM])
		return -EINVAL;

	helper->expect_class_max =
		ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));

	if (helper->expect_class_max != 0 &&
	    helper->expect_class_max > NF_CT_MAX_EXPECT_CLASSES)
		return -EOVERFLOW;

	expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
				helper->expect_class_max, GFP_KERNEL);
	if (expect_policy == NULL)
		return -ENOMEM;

	for (i=0; i<helper->expect_class_max; i++) {
		if (!tb[NFCTH_POLICY_SET+i])
			goto err;

		ret = nfnl_cthelper_expect_policy(&expect_policy[i],
						  tb[NFCTH_POLICY_SET+i]);
		if (ret < 0)
			goto err;
	}
	helper->expect_policy = expect_policy;
	return 0;
err:
	kfree(expect_policy);
	return -EINVAL;
}

static int
nfnl_cthelper_create(const struct nlattr * const tb[],
		     struct nf_conntrack_tuple *tuple)
{
	struct nf_conntrack_helper *helper;
	int ret;

	if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
		return -EINVAL;

	helper = kzalloc(sizeof(struct nf_conntrack_helper), GFP_KERNEL);
	if (helper == NULL)
		return -ENOMEM;

	ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
	if (ret < 0)
		goto err;

	strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
	helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
	helper->flags |= NF_CT_HELPER_F_USERSPACE;
	memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));

	helper->me = THIS_MODULE;
	helper->help = nfnl_userspace_cthelper;
	helper->from_nlattr = nfnl_cthelper_from_nlattr;
	helper->to_nlattr = nfnl_cthelper_to_nlattr;

	/* Default to queue number zero, this can be updated at any time. */
	if (tb[NFCTH_QUEUE_NUM])
		helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));

	if (tb[NFCTH_STATUS]) {
		int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));

		switch(status) {
		case NFCT_HELPER_STATUS_ENABLED:
			helper->flags |= NF_CT_HELPER_F_CONFIGURED;
			break;
		case NFCT_HELPER_STATUS_DISABLED:
			helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
			break;
		}
	}

	ret = nf_conntrack_helper_register(helper);
	if (ret < 0)
		goto err;

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

static int
nfnl_cthelper_update(const struct nlattr * const tb[],
		     struct nf_conntrack_helper *helper)
{
	int ret;

	if (tb[NFCTH_PRIV_DATA_LEN])
		return -EBUSY;

	if (tb[NFCTH_POLICY]) {
		ret = nfnl_cthelper_parse_expect_policy(helper,
							tb[NFCTH_POLICY]);
		if (ret < 0)
			return ret;
	}
	if (tb[NFCTH_QUEUE_NUM])
		helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));

	if (tb[NFCTH_STATUS]) {
		int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));

		switch(status) {
		case NFCT_HELPER_STATUS_ENABLED:
			helper->flags |= NF_CT_HELPER_F_CONFIGURED;
			break;
		case NFCT_HELPER_STATUS_DISABLED:
			helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
			break;
		}
	}
	return 0;
}

static int
nfnl_cthelper_new(struct sock *nfnl, struct sk_buff *skb,
		  const struct nlmsghdr *nlh, const struct nlattr * const tb[])
{
	const char *helper_name;
	struct nf_conntrack_helper *cur, *helper = NULL;
	struct nf_conntrack_tuple tuple;
	int ret = 0, i;

	if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
		return -EINVAL;

	helper_name = nla_data(tb[NFCTH_NAME]);

	ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
	if (ret < 0)
		return ret;

	rcu_read_lock();
	for (i = 0; i < nf_ct_helper_hsize && !helper; i++) {
		hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {

			/* skip non-userspace conntrack helpers. */
			if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
				continue;

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

			if ((tuple.src.l3num != cur->tuple.src.l3num ||
			     tuple.dst.protonum != cur->tuple.dst.protonum))
				continue;

			if (nlh->nlmsg_flags & NLM_F_EXCL) {
				ret = -EEXIST;
				goto err;
			}
			helper = cur;
			break;
		}
	}
	rcu_read_unlock();

	if (helper == NULL)
		ret = nfnl_cthelper_create(tb, &tuple);
	else
		ret = nfnl_cthelper_update(tb, helper);

	return ret;
err:
	rcu_read_unlock();
	return ret;
}

static int
nfnl_cthelper_dump_tuple(struct sk_buff *skb,
			 struct nf_conntrack_helper *helper)
{
	struct nlattr *nest_parms;

	nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
	if (nest_parms == NULL)
		goto nla_put_failure;

	if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
			 htons(helper->tuple.src.l3num)))
		goto nla_put_failure;

	if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
		goto nla_put_failure;

	nla_nest_end(skb, nest_parms);
	return 0;

nla_put_failure:
	return -1;
}

static int
nfnl_cthelper_dump_policy(struct sk_buff *skb,
			struct nf_conntrack_helper *helper)
{
	int i;
	struct nlattr *nest_parms1, *nest_parms2;

	nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
	if (nest_parms1 == NULL)
		goto nla_put_failure;

	if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
			 htonl(helper->expect_class_max)))
		goto nla_put_failure;

	for (i=0; i<helper->expect_class_max; i++) {
		nest_parms2 = nla_nest_start(skb,
				(NFCTH_POLICY_SET+i) | NLA_F_NESTED);
		if (nest_parms2 == NULL)
			goto nla_put_failure;

		if (nla_put_string(skb, NFCTH_POLICY_NAME,
				   helper->expect_policy[i].name))
			goto nla_put_failure;

		if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
				 htonl(helper->expect_policy[i].max_expected)))
			goto nla_put_failure;

		if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
				 htonl(helper->expect_policy[i].timeout)))
			goto nla_put_failure;

		nla_nest_end(skb, nest_parms2);
	}
	nla_nest_end(skb, nest_parms1);
	return 0;

nla_put_failure:
	return -1;
}

static int
nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
			int event, struct nf_conntrack_helper *helper)
{
	struct nlmsghdr *nlh;
	struct nfgenmsg *nfmsg;
	unsigned int flags = portid ? NLM_F_MULTI : 0;
	int status;

	event |= NFNL_SUBSYS_CTHELPER << 8;
	nlh = nlmsg_put(skb, portid, 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;

	if (nla_put_string(skb, NFCTH_NAME, helper->name))
		goto nla_put_failure;

	if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
		goto nla_put_failure;

	if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
		goto nla_put_failure;

	if (nfnl_cthelper_dump_policy(skb, helper) < 0)
		goto nla_put_failure;

	if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
		goto nla_put_failure;

	if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
		status = NFCT_HELPER_STATUS_ENABLED;
	else
		status = NFCT_HELPER_STATUS_DISABLED;

	if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
		goto nla_put_failure;

	nlmsg_end(skb, nlh);
	return skb->len;

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

static int
nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct nf_conntrack_helper *cur, *last;

	rcu_read_lock();
	last = (struct nf_conntrack_helper *)cb->args[1];
	for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
restart:
		hlist_for_each_entry_rcu(cur,
				&nf_ct_helper_hash[cb->args[0]], hnode) {

			/* skip non-userspace conntrack helpers. */
			if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
				continue;

			if (cb->args[1]) {
				if (cur != last)
					continue;
				cb->args[1] = 0;
			}
			if (nfnl_cthelper_fill_info(skb,
					    NETLINK_CB(cb->skb).portid,
					    cb->nlh->nlmsg_seq,
					    NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
					    NFNL_MSG_CTHELPER_NEW, cur) < 0) {
				cb->args[1] = (unsigned long)cur;
				goto out;
			}
		}
	}
	if (cb->args[1]) {
		cb->args[1] = 0;
		goto restart;
	}
out:
	rcu_read_unlock();
	return skb->len;
}

static int
nfnl_cthelper_get(struct sock *nfnl, struct sk_buff *skb,
		  const struct nlmsghdr *nlh, const struct nlattr * const tb[])
{
	int ret = -ENOENT, i;
	struct nf_conntrack_helper *cur;
	struct sk_buff *skb2;
	char *helper_name = NULL;
	struct nf_conntrack_tuple tuple;
	bool tuple_set = false;

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

	if (tb[NFCTH_NAME])
		helper_name = nla_data(tb[NFCTH_NAME]);

	if (tb[NFCTH_TUPLE]) {
		ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
		if (ret < 0)
			return ret;

		tuple_set = true;
	}

	for (i = 0; i < nf_ct_helper_hsize; i++) {
		hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {

			/* skip non-userspace conntrack helpers. */
			if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
				continue;

			if (helper_name && strncmp(cur->name, helper_name,
						NF_CT_HELPER_NAME_LEN) != 0) {
				continue;
			}
			if (tuple_set &&
			    (tuple.src.l3num != cur->tuple.src.l3num ||
			     tuple.dst.protonum != cur->tuple.dst.protonum))
				continue;

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

			ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
						nlh->nlmsg_seq,
						NFNL_MSG_TYPE(nlh->nlmsg_type),
						NFNL_MSG_CTHELPER_NEW, cur);
			if (ret <= 0) {
				kfree_skb(skb2);
				break;
			}

			ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
						MSG_DONTWAIT);
			if (ret > 0)
				ret = 0;

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

static int
nfnl_cthelper_del(struct sock *nfnl, struct sk_buff *skb,
	     const struct nlmsghdr *nlh, const struct nlattr * const tb[])
{
	char *helper_name = NULL;
	struct nf_conntrack_helper *cur;
	struct hlist_node *tmp;
	struct nf_conntrack_tuple tuple;
	bool tuple_set = false, found = false;
	int i, j = 0, ret;

	if (tb[NFCTH_NAME])
		helper_name = nla_data(tb[NFCTH_NAME]);

	if (tb[NFCTH_TUPLE]) {
		ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
		if (ret < 0)
			return ret;

		tuple_set = true;
	}

	for (i = 0; i < nf_ct_helper_hsize; i++) {
		hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
								hnode) {
			/* skip non-userspace conntrack helpers. */
			if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
				continue;

			j++;

			if (helper_name && strncmp(cur->name, helper_name,
						NF_CT_HELPER_NAME_LEN) != 0) {
				continue;
			}
			if (tuple_set &&
			    (tuple.src.l3num != cur->tuple.src.l3num ||
			     tuple.dst.protonum != cur->tuple.dst.protonum))
				continue;

			found = true;
			nf_conntrack_helper_unregister(cur);
		}
	}
	/* Make sure we return success if we flush and there is no helpers */
	return (found || j == 0) ? 0 : -ENOENT;
}

static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
	[NFCTH_NAME] = { .type = NLA_NUL_STRING,
			 .len = NF_CT_HELPER_NAME_LEN-1 },
	[NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
};

static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
	[NFNL_MSG_CTHELPER_NEW]		= { .call = nfnl_cthelper_new,
					    .attr_count = NFCTH_MAX,
					    .policy = nfnl_cthelper_policy },
	[NFNL_MSG_CTHELPER_GET]		= { .call = nfnl_cthelper_get,
					    .attr_count = NFCTH_MAX,
					    .policy = nfnl_cthelper_policy },
	[NFNL_MSG_CTHELPER_DEL]		= { .call = nfnl_cthelper_del,
					    .attr_count = NFCTH_MAX,
					    .policy = nfnl_cthelper_policy },
};

static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
	.name				= "cthelper",
	.subsys_id			= NFNL_SUBSYS_CTHELPER,
	.cb_count			= NFNL_MSG_CTHELPER_MAX,
	.cb				= nfnl_cthelper_cb,
};

MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);

static int __init nfnl_cthelper_init(void)
{
	int ret;

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

static void __exit nfnl_cthelper_exit(void)
{
	struct nf_conntrack_helper *cur;
	struct hlist_node *tmp;
	int i;

	nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);

	for (i=0; i<nf_ct_helper_hsize; i++) {
		hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
									hnode) {
			/* skip non-userspace conntrack helpers. */
			if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
				continue;

			nf_conntrack_helper_unregister(cur);
		}
	}
}

module_init(nfnl_cthelper_init);
module_exit(nfnl_cthelper_exit);
Commit	Line	Data
12f7a505 PNA	1	/*
	2	* (C) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation (or any later at your option).
	7	*
	8	* This software has been sponsored by Vyatta Inc. <http://www.vyatta.com>
	9	*/
	10	#include <linux/init.h>
	11	#include <linux/module.h>
	12	#include <linux/kernel.h>
	13	#include <linux/skbuff.h>
	14	#include <linux/netlink.h>
	15	#include <linux/rculist.h>
	16	#include <linux/slab.h>
	17	#include <linux/types.h>
	18	#include <linux/list.h>
	19	#include <linux/errno.h>
	20	#include <net/netlink.h>
	21	#include <net/sock.h>
	22
	23	#include <net/netfilter/nf_conntrack_helper.h>
	24	#include <net/netfilter/nf_conntrack_expect.h>
	25	#include <net/netfilter/nf_conntrack_ecache.h>
	26
	27	#include <linux/netfilter/nfnetlink.h>
	28	#include <linux/netfilter/nfnetlink_conntrack.h>
	29	#include <linux/netfilter/nfnetlink_cthelper.h>
	30
	31	MODULE_LICENSE("GPL");
	32	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
	33	MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers");
	34
	35	static int
	36	nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
	37	struct nf_conn *ct, enum ip_conntrack_info ctinfo)
	38	{
	39	const struct nf_conn_help *help;
	40	struct nf_conntrack_helper *helper;
	41
	42	help = nfct_help(ct);
	43	if (help == NULL)
	44	return NF_DROP;
	45
	46	/* rcu_read_lock()ed by nf_hook_slow */
	47	helper = rcu_dereference(help->helper);
	48	if (helper == NULL)
	49	return NF_DROP;
	50
	51	/* This is an user-space helper not yet configured, skip. */
	52	if ((helper->flags &
	53	(NF_CT_HELPER_F_USERSPACE \| NF_CT_HELPER_F_CONFIGURED)) ==
	54	NF_CT_HELPER_F_USERSPACE)
	55	return NF_ACCEPT;
	56
	57	/* If the user-space helper is not available, don't block traffic. */
	58	return NF_QUEUE_NR(helper->queue_num) \| NF_VERDICT_FLAG_QUEUE_BYPASS;
	59	}
	60
	61	static const struct nla_policy nfnl_cthelper_tuple_pol[NFCTH_TUPLE_MAX+1] = {
	62	[NFCTH_TUPLE_L3PROTONUM] = { .type = NLA_U16, },
	63	[NFCTH_TUPLE_L4PROTONUM] = { .type = NLA_U8, },
	64	};
65
66	static int
67	nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
68	const struct nlattr *attr)
69	{
130ffbc2	70	int err;
12f7a505 PNA	71	struct nlattr *tb[NFCTH_TUPLE_MAX+1];
12f7a505 PNA	72
130ffbc2 DB	73	err = nla_parse_nested(tb, NFCTH_TUPLE_MAX, attr, nfnl_cthelper_tuple_pol);
	74	if (err < 0)
	75	return err;
12f7a505 PNA	76
	77	if (!tb[NFCTH_TUPLE_L3PROTONUM] \|\| !tb[NFCTH_TUPLE_L4PROTONUM])
	78	return -EINVAL;
	79
fe31d1a8	80	tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
12f7a505 PNA	81	tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
	82
	83	return 0;
	84	}
	85
	86	static int
	87	nfnl_cthelper_from_nlattr(struct nlattr attr, struct nf_conn ct)
	88	{
b18c5d15	89	struct nf_conn_help *help = nfct_help(ct);
12f7a505	90
7be54ca4 PNA	91	if (attr == NULL)
	92	return -EINVAL;
	93
12f7a505 PNA	94	if (help->helper->data_len == 0)
	95	return -EINVAL;
	96
b18c5d15	97	memcpy(help->data, nla_data(attr), help->helper->data_len);
12f7a505 PNA	98	return 0;
	99	}
	100
	101	static int
	102	nfnl_cthelper_to_nlattr(struct sk_buff skb, const struct nf_conn ct)
	103	{
	104	const struct nf_conn_help *help = nfct_help(ct);
	105
	106	if (help->helper->data_len &&
	107	nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
	108	goto nla_put_failure;
	109
	110	return 0;
	111
	112	nla_put_failure:
	113	return -ENOSPC;
	114	}
	115
	116	static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
	117	[NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
	118	.len = NF_CT_HELPER_NAME_LEN-1 },
	119	[NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
	120	[NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
	121	};
	122
	123	static int
	124	nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
	125	const struct nlattr *attr)
	126	{
130ffbc2	127	int err;
12f7a505 PNA	128	struct nlattr *tb[NFCTH_POLICY_MAX+1];
12f7a505 PNA	129
130ffbc2 DB	130	err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr, nfnl_cthelper_expect_pol);
	131	if (err < 0)
	132	return err;
12f7a505 PNA	133
	134	if (!tb[NFCTH_POLICY_NAME] \|\|
	135	!tb[NFCTH_POLICY_EXPECT_MAX] \|\|
	136	!tb[NFCTH_POLICY_EXPECT_TIMEOUT])
	137	return -EINVAL;
	138
	139	strncpy(expect_policy->name,
	140	nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
	141	expect_policy->max_expected =
	142	ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
	143	expect_policy->timeout =
	144	ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
	145
	146	return 0;
	147	}
	148
	149	static const struct nla_policy
	150	nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
	151	[NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
	152	};
	153
	154	static int
	155	nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
	156	const struct nlattr *attr)
	157	{
	158	int i, ret;
	159	struct nf_conntrack_expect_policy *expect_policy;
	160	struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
	161
130ffbc2 DB	162	ret = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
	163	nfnl_cthelper_expect_policy_set);
	164	if (ret < 0)
	165	return ret;
12f7a505 PNA	166
	167	if (!tb[NFCTH_POLICY_SET_NUM])
	168	return -EINVAL;
	169
	170	helper->expect_class_max =
	171	ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
	172
	173	if (helper->expect_class_max != 0 &&
	174	helper->expect_class_max > NF_CT_MAX_EXPECT_CLASSES)
	175	return -EOVERFLOW;
	176
	177	expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
	178	helper->expect_class_max, GFP_KERNEL);
	179	if (expect_policy == NULL)
	180	return -ENOMEM;
	181
	182	for (i=0; i<helper->expect_class_max; i++) {
	183	if (!tb[NFCTH_POLICY_SET+i])
	184	goto err;
	185
	186	ret = nfnl_cthelper_expect_policy(&expect_policy[i],
	187	tb[NFCTH_POLICY_SET+i]);
	188	if (ret < 0)
	189	goto err;
	190	}
	191	helper->expect_policy = expect_policy;
	192	return 0;
	193	err:
	194	kfree(expect_policy);
	195	return -EINVAL;
	196	}
	197
	198	static int
	199	nfnl_cthelper_create(const struct nlattr * const tb[],
	200	struct nf_conntrack_tuple *tuple)
	201	{
	202	struct nf_conntrack_helper *helper;
	203	int ret;
	204
	205	if (!tb[NFCTH_TUPLE] \|\| !tb[NFCTH_POLICY] \|\| !tb[NFCTH_PRIV_DATA_LEN])
	206	return -EINVAL;
	207
	208	helper = kzalloc(sizeof(struct nf_conntrack_helper), GFP_KERNEL);
	209	if (helper == NULL)
	210	return -ENOMEM;
	211
	212	ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
	213	if (ret < 0)
	214	goto err;
	215
	216	strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
	217	helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
	218	helper->flags \|= NF_CT_HELPER_F_USERSPACE;
	219	memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
	220
	221	helper->me = THIS_MODULE;
	222	helper->help = nfnl_userspace_cthelper;
	223	helper->from_nlattr = nfnl_cthelper_from_nlattr;
	224	helper->to_nlattr = nfnl_cthelper_to_nlattr;
	225
	226	/* Default to queue number zero, this can be updated at any time. */
	227	if (tb[NFCTH_QUEUE_NUM])
	228	helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
	229
230	if (tb[NFCTH_STATUS]) {
231	int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
232
233	switch(status) {
234	case NFCT_HELPER_STATUS_ENABLED:
235	helper->flags \|= NF_CT_HELPER_F_CONFIGURED;
236	break;
237	case NFCT_HELPER_STATUS_DISABLED:
238	helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
239	break;
240	}
241	}
242
243	ret = nf_conntrack_helper_register(helper);
244	if (ret < 0)
245	goto err;
246
247	return 0;
248	err:
249	kfree(helper);
250	return ret;
251	}
252
253	static int
254	nfnl_cthelper_update(const struct nlattr * const tb[],
255	struct nf_conntrack_helper *helper)
256	{
257	int ret;
258
259	if (tb[NFCTH_PRIV_DATA_LEN])
260	return -EBUSY;
261
262	if (tb[NFCTH_POLICY]) {
263	ret = nfnl_cthelper_parse_expect_policy(helper,
264	tb[NFCTH_POLICY]);
265	if (ret < 0)
266	return ret;
267	}
268	if (tb[NFCTH_QUEUE_NUM])
269	helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
270
271	if (tb[NFCTH_STATUS]) {
272	int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
273
274	switch(status) {
275	case NFCT_HELPER_STATUS_ENABLED:
276	helper->flags \|= NF_CT_HELPER_F_CONFIGURED;
277	break;
278	case NFCT_HELPER_STATUS_DISABLED:
279	helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
280	break;
281	}
282	}
283	return 0;
284	}
285
286	static int
287	nfnl_cthelper_new(struct sock nfnl, struct sk_buff skb,
288	const struct nlmsghdr nlh, const struct nlattr const tb[])
289	{
290	const char *helper_name;
291	struct nf_conntrack_helper cur, helper = NULL;
292	struct nf_conntrack_tuple tuple;
12f7a505 PNA	293	int ret = 0, i;
	294
	295	if (!tb[NFCTH_NAME] \|\| !tb[NFCTH_TUPLE])
	296	return -EINVAL;
	297
	298	helper_name = nla_data(tb[NFCTH_NAME]);
	299
	300	ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
	301	if (ret < 0)
	302	return ret;
	303
	304	rcu_read_lock();
	305	for (i = 0; i < nf_ct_helper_hsize && !helper; i++) {
b67bfe0d	306	hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {
12f7a505 PNA	307
	308	/* skip non-userspace conntrack helpers. */
	309	if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
	310	continue;
	311
	312	if (strncmp(cur->name, helper_name,
	313	NF_CT_HELPER_NAME_LEN) != 0)
	314	continue;
	315
	316	if ((tuple.src.l3num != cur->tuple.src.l3num \|\|
	317	tuple.dst.protonum != cur->tuple.dst.protonum))
	318	continue;
	319
	320	if (nlh->nlmsg_flags & NLM_F_EXCL) {
	321	ret = -EEXIST;
	322	goto err;
	323	}
	324	helper = cur;
	325	break;
	326	}
	327	}
	328	rcu_read_unlock();
	329
	330	if (helper == NULL)
	331	ret = nfnl_cthelper_create(tb, &tuple);
	332	else
	333	ret = nfnl_cthelper_update(tb, helper);
	334
	335	return ret;
	336	err:
	337	rcu_read_unlock();
	338	return ret;
	339	}
	340
	341	static int
	342	nfnl_cthelper_dump_tuple(struct sk_buff *skb,
	343	struct nf_conntrack_helper *helper)
	344	{
	345	struct nlattr *nest_parms;
	346
	347	nest_parms = nla_nest_start(skb, NFCTH_TUPLE \| NLA_F_NESTED);
	348	if (nest_parms == NULL)
	349	goto nla_put_failure;
	350
	351	if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
	352	htons(helper->tuple.src.l3num)))
	353	goto nla_put_failure;
	354
	355	if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
	356	goto nla_put_failure;
	357
	358	nla_nest_end(skb, nest_parms);
	359	return 0;
	360
	361	nla_put_failure:
	362	return -1;
	363	}
	364
	365	static int
	366	nfnl_cthelper_dump_policy(struct sk_buff *skb,
	367	struct nf_conntrack_helper *helper)
	368	{
	369	int i;
	370	struct nlattr nest_parms1, nest_parms2;
371
372	nest_parms1 = nla_nest_start(skb, NFCTH_POLICY \| NLA_F_NESTED);
373	if (nest_parms1 == NULL)
374	goto nla_put_failure;
375
376	if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
377	htonl(helper->expect_class_max)))
378	goto nla_put_failure;
379
380	for (i=0; i<helper->expect_class_max; i++) {
381	nest_parms2 = nla_nest_start(skb,
382	(NFCTH_POLICY_SET+i) \| NLA_F_NESTED);
383	if (nest_parms2 == NULL)
384	goto nla_put_failure;
385
386	if (nla_put_string(skb, NFCTH_POLICY_NAME,
387	helper->expect_policy[i].name))
388	goto nla_put_failure;
389
390	if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
391	htonl(helper->expect_policy[i].max_expected)))
392	goto nla_put_failure;
393
394	if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
395	htonl(helper->expect_policy[i].timeout)))
396	goto nla_put_failure;
397
398	nla_nest_end(skb, nest_parms2);
399	}
400	nla_nest_end(skb, nest_parms1);
401	return 0;
402
403	nla_put_failure:
404	return -1;
405	}
406
407	static int
15e47304	408	nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
12f7a505 PNA	409	int event, struct nf_conntrack_helper *helper)
	410	{
	411	struct nlmsghdr *nlh;
	412	struct nfgenmsg *nfmsg;
15e47304	413	unsigned int flags = portid ? NLM_F_MULTI : 0;
12f7a505 PNA	414	int status;
	415
	416	event \|= NFNL_SUBSYS_CTHELPER << 8;
15e47304	417	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
12f7a505 PNA	418	if (nlh == NULL)
	419	goto nlmsg_failure;
	420
	421	nfmsg = nlmsg_data(nlh);
	422	nfmsg->nfgen_family = AF_UNSPEC;
	423	nfmsg->version = NFNETLINK_V0;
	424	nfmsg->res_id = 0;
	425
	426	if (nla_put_string(skb, NFCTH_NAME, helper->name))
	427	goto nla_put_failure;
	428
	429	if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
	430	goto nla_put_failure;
	431
	432	if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
	433	goto nla_put_failure;
	434
	435	if (nfnl_cthelper_dump_policy(skb, helper) < 0)
	436	goto nla_put_failure;
	437
	438	if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
	439	goto nla_put_failure;
	440
	441	if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
	442	status = NFCT_HELPER_STATUS_ENABLED;
	443	else
	444	status = NFCT_HELPER_STATUS_DISABLED;
	445
	446	if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
	447	goto nla_put_failure;
	448
	449	nlmsg_end(skb, nlh);
	450	return skb->len;
	451
	452	nlmsg_failure:
	453	nla_put_failure:
	454	nlmsg_cancel(skb, nlh);
	455	return -1;
	456	}
	457
	458	static int
	459	nfnl_cthelper_dump_table(struct sk_buff skb, struct netlink_callback cb)
	460	{
	461	struct nf_conntrack_helper cur, last;
12f7a505 PNA	462
	463	rcu_read_lock();
	464	last = (struct nf_conntrack_helper *)cb->args[1];
	465	for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
	466	restart:
b67bfe0d	467	hlist_for_each_entry_rcu(cur,
12f7a505 PNA	468	&nf_ct_helper_hash[cb->args[0]], hnode) {
	469
	470	/* skip non-userspace conntrack helpers. */
	471	if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
	472	continue;
	473
	474	if (cb->args[1]) {
	475	if (cur != last)
	476	continue;
	477	cb->args[1] = 0;
	478	}
	479	if (nfnl_cthelper_fill_info(skb,
15e47304	480	NETLINK_CB(cb->skb).portid,
12f7a505 PNA	481	cb->nlh->nlmsg_seq,
	482	NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
	483	NFNL_MSG_CTHELPER_NEW, cur) < 0) {
	484	cb->args[1] = (unsigned long)cur;
	485	goto out;
	486	}
	487	}
	488	}
	489	if (cb->args[1]) {
	490	cb->args[1] = 0;
	491	goto restart;
	492	}
	493	out:
	494	rcu_read_unlock();
	495	return skb->len;
	496	}
	497
	498	static int
	499	nfnl_cthelper_get(struct sock nfnl, struct sk_buff skb,
	500	const struct nlmsghdr nlh, const struct nlattr const tb[])
	501	{
	502	int ret = -ENOENT, i;
	503	struct nf_conntrack_helper *cur;
12f7a505 PNA	504	struct sk_buff *skb2;
	505	char *helper_name = NULL;
	506	struct nf_conntrack_tuple tuple;
	507	bool tuple_set = false;
	508
	509	if (nlh->nlmsg_flags & NLM_F_DUMP) {
	510	struct netlink_dump_control c = {
	511	.dump = nfnl_cthelper_dump_table,
	512	};
	513	return netlink_dump_start(nfnl, skb, nlh, &c);
	514	}
	515
	516	if (tb[NFCTH_NAME])
	517	helper_name = nla_data(tb[NFCTH_NAME]);
	518
	519	if (tb[NFCTH_TUPLE]) {
	520	ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
	521	if (ret < 0)
	522	return ret;
	523
	524	tuple_set = true;
	525	}
	526
	527	for (i = 0; i < nf_ct_helper_hsize; i++) {
b67bfe0d	528	hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {
12f7a505 PNA	529
	530	/* skip non-userspace conntrack helpers. */
	531	if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
	532	continue;
	533
	534	if (helper_name && strncmp(cur->name, helper_name,
	535	NF_CT_HELPER_NAME_LEN) != 0) {
	536	continue;
	537	}
	538	if (tuple_set &&
	539	(tuple.src.l3num != cur->tuple.src.l3num \|\|
	540	tuple.dst.protonum != cur->tuple.dst.protonum))
	541	continue;
	542
	543	skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	544	if (skb2 == NULL) {
	545	ret = -ENOMEM;
	546	break;
	547	}
	548
15e47304	549	ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
12f7a505 PNA	550	nlh->nlmsg_seq,
	551	NFNL_MSG_TYPE(nlh->nlmsg_type),
	552	NFNL_MSG_CTHELPER_NEW, cur);
	553	if (ret <= 0) {
	554	kfree_skb(skb2);
	555	break;
	556	}
	557
15e47304	558	ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
12f7a505 PNA	559	MSG_DONTWAIT);
	560	if (ret > 0)
	561	ret = 0;
	562
	563	/* this avoids a loop in nfnetlink. */
	564	return ret == -EAGAIN ? -ENOBUFS : ret;
	565	}
	566	}
	567	return ret;
	568	}
	569
	570	static int
	571	nfnl_cthelper_del(struct sock nfnl, struct sk_buff skb,
	572	const struct nlmsghdr nlh, const struct nlattr const tb[])
	573	{
	574	char *helper_name = NULL;
	575	struct nf_conntrack_helper *cur;
b67bfe0d	576	struct hlist_node *tmp;
12f7a505 PNA	577	struct nf_conntrack_tuple tuple;
	578	bool tuple_set = false, found = false;
	579	int i, j = 0, ret;
	580
	581	if (tb[NFCTH_NAME])
	582	helper_name = nla_data(tb[NFCTH_NAME]);
	583
	584	if (tb[NFCTH_TUPLE]) {
	585	ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
	586	if (ret < 0)
	587	return ret;
	588
	589	tuple_set = true;
	590	}
	591
	592	for (i = 0; i < nf_ct_helper_hsize; i++) {
b67bfe0d	593	hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
12f7a505 PNA	594	hnode) {
	595	/* skip non-userspace conntrack helpers. */
	596	if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
	597	continue;
	598
	599	j++;
	600
	601	if (helper_name && strncmp(cur->name, helper_name,
	602	NF_CT_HELPER_NAME_LEN) != 0) {
	603	continue;
	604	}
	605	if (tuple_set &&
	606	(tuple.src.l3num != cur->tuple.src.l3num \|\|
	607	tuple.dst.protonum != cur->tuple.dst.protonum))
	608	continue;
	609
	610	found = true;
	611	nf_conntrack_helper_unregister(cur);
	612	}
	613	}
	614	/* Make sure we return success if we flush and there is no helpers */
	615	return (found \|\| j == 0) ? 0 : -ENOENT;
	616	}
	617
	618	static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
	619	[NFCTH_NAME] = { .type = NLA_NUL_STRING,
	620	.len = NF_CT_HELPER_NAME_LEN-1 },
	621	[NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
	622	};
	623
	624	static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
	625	[NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new,
	626	.attr_count = NFCTH_MAX,
	627	.policy = nfnl_cthelper_policy },
	628	[NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get,
	629	.attr_count = NFCTH_MAX,
	630	.policy = nfnl_cthelper_policy },
	631	[NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del,
	632	.attr_count = NFCTH_MAX,
	633	.policy = nfnl_cthelper_policy },
	634	};
	635
	636	static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
	637	.name = "cthelper",
	638	.subsys_id = NFNL_SUBSYS_CTHELPER,
	639	.cb_count = NFNL_MSG_CTHELPER_MAX,
	640	.cb = nfnl_cthelper_cb,
	641	};
	642
	643	MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
	644
	645	static int __init nfnl_cthelper_init(void)
	646	{
	647	int ret;
	648
	649	ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
	650	if (ret < 0) {
	651	pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
	652	goto err_out;
	653	}
	654	return 0;
	655	err_out:
	656	return ret;
	657	}
658
659	static void __exit nfnl_cthelper_exit(void)
660	{
661	struct nf_conntrack_helper *cur;
b67bfe0d	662	struct hlist_node *tmp;
12f7a505 PNA	663	int i;
	664
	665	nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
	666
	667	for (i=0; i<nf_ct_helper_hsize; i++) {
b67bfe0d	668	hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
12f7a505 PNA	669	hnode) {
	670	/* skip non-userspace conntrack helpers. */
	671	if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
	672	continue;
	673
	674	nf_conntrack_helper_unregister(cur);
	675	}
	676	}
	677	}
	678
	679	module_init(nfnl_cthelper_init);
	680	module_exit(nfnl_cthelper_exit);