net/netfilter/nft_meta.c - linux - Git at Google

 /*
  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
  *
  * 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.
  *
  * Development of this code funded by Astaro AG (http://www.astaro.com/)
  */

 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/netlink.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 #include <linux/in.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/smp.h>
 #include <net/dst.h>
 #include <net/sock.h>
 #include <net/tcp_states.h> /* for TCP_TIME_WAIT */
 #include <net/netfilter/nf_tables.h>
 #include <net/netfilter/nft_meta.h>

 void nft_meta_get_eval(const struct nft_expr *expr,
 		       struct nft_data data[NFT_REG_MAX + 1],
 		       const struct nft_pktinfo *pkt)
 {
 	const struct nft_meta *priv = nft_expr_priv(expr);
 	const struct sk_buff *skb = pkt->skb;
 	const struct net_device *in = pkt->in, *out = pkt->out;
 	struct nft_data *dest = &data[priv->dreg];

 	switch (priv->key) {
 	case NFT_META_LEN:
 		dest->data[0] = skb->len;
 		break;
 	case NFT_META_PROTOCOL:
 		*(__be16 *)dest->data = skb->protocol;
 		break;
 	case NFT_META_NFPROTO:
 		dest->data[0] = pkt->ops->pf;
 		break;
 	case NFT_META_L4PROTO:
 		dest->data[0] = pkt->tprot;
 		break;
 	case NFT_META_PRIORITY:
 		dest->data[0] = skb->priority;
 		break;
 	case NFT_META_MARK:
 		dest->data[0] = skb->mark;
 		break;
 	case NFT_META_IIF:
 		if (in == NULL)
 			goto err;
 		dest->data[0] = in->ifindex;
 		break;
 	case NFT_META_OIF:
 		if (out == NULL)
 			goto err;
 		dest->data[0] = out->ifindex;
 		break;
 	case NFT_META_IIFNAME:
 		if (in == NULL)
 			goto err;
 		strncpy((char *)dest->data, in->name, sizeof(dest->data));
 		break;
 	case NFT_META_OIFNAME:
 		if (out == NULL)
 			goto err;
 		strncpy((char *)dest->data, out->name, sizeof(dest->data));
 		break;
 	case NFT_META_IIFTYPE:
 		if (in == NULL)
 			goto err;
 		*(u16 *)dest->data = in->type;
 		break;
 	case NFT_META_OIFTYPE:
 		if (out == NULL)
 			goto err;
 		*(u16 *)dest->data = out->type;
 		break;
 	case NFT_META_SKUID:
 		if (skb->sk == NULL || skb->sk->sk_state == TCP_TIME_WAIT)
 			goto err;

 		read_lock_bh(&skb->sk->sk_callback_lock);
 		if (skb->sk->sk_socket == NULL ||
 		    skb->sk->sk_socket->file == NULL) {
 			read_unlock_bh(&skb->sk->sk_callback_lock);
 			goto err;
 		}

 		dest->data[0] =
 			from_kuid_munged(&init_user_ns,
 				skb->sk->sk_socket->file->f_cred->fsuid);
 		read_unlock_bh(&skb->sk->sk_callback_lock);
 		break;
 	case NFT_META_SKGID:
 		if (skb->sk == NULL || skb->sk->sk_state == TCP_TIME_WAIT)
 			goto err;

 		read_lock_bh(&skb->sk->sk_callback_lock);
 		if (skb->sk->sk_socket == NULL ||
 		    skb->sk->sk_socket->file == NULL) {
 			read_unlock_bh(&skb->sk->sk_callback_lock);
 			goto err;
 		}
 		dest->data[0] =
 			from_kgid_munged(&init_user_ns,
 				 skb->sk->sk_socket->file->f_cred->fsgid);
 		read_unlock_bh(&skb->sk->sk_callback_lock);
 		break;
 #ifdef CONFIG_IP_ROUTE_CLASSID
 	case NFT_META_RTCLASSID: {
 		const struct dst_entry *dst = skb_dst(skb);

 		if (dst == NULL)
 			goto err;
 		dest->data[0] = dst->tclassid;
 		break;
 	}
 #endif
 #ifdef CONFIG_NETWORK_SECMARK
 	case NFT_META_SECMARK:
 		dest->data[0] = skb->secmark;
 		break;
 #endif
 	case NFT_META_PKTTYPE:
 		if (skb->pkt_type != PACKET_LOOPBACK) {
 			dest->data[0] = skb->pkt_type;
 			break;
 		}

 		switch (pkt->ops->pf) {
 		case NFPROTO_IPV4:
 			if (ipv4_is_multicast(ip_hdr(skb)->daddr))
 				dest->data[0] = PACKET_MULTICAST;
 			else
 				dest->data[0] = PACKET_BROADCAST;
 			break;
 		case NFPROTO_IPV6:
 			if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
 				dest->data[0] = PACKET_MULTICAST;
 			else
 				dest->data[0] = PACKET_BROADCAST;
 			break;
 		default:
 			WARN_ON(1);
 			goto err;
 		}
 		break;
 	case NFT_META_CPU:
 		dest->data[0] = smp_processor_id();
 		break;
 	case NFT_META_IIFGROUP:
 		if (in == NULL)
 			goto err;
 		dest->data[0] = in->group;
 		break;
 	case NFT_META_OIFGROUP:
 		if (out == NULL)
 			goto err;
 		dest->data[0] = out->group;
 		break;
 	default:
 		WARN_ON(1);
 		goto err;
 	}
 	return;

 err:
 	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
 }
 EXPORT_SYMBOL_GPL(nft_meta_get_eval);

 void nft_meta_set_eval(const struct nft_expr *expr,
 		       struct nft_data data[NFT_REG_MAX + 1],
 		       const struct nft_pktinfo *pkt)
 {
 	const struct nft_meta *meta = nft_expr_priv(expr);
 	struct sk_buff *skb = pkt->skb;
 	u32 value = data[meta->sreg].data[0];

 	switch (meta->key) {
 	case NFT_META_MARK:
 		skb->mark = value;
 		break;
 	case NFT_META_PRIORITY:
 		skb->priority = value;
 		break;
 	case NFT_META_NFTRACE:
 		skb->nf_trace = 1;
 		break;
 	default:
 		WARN_ON(1);
 	}
 }
 EXPORT_SYMBOL_GPL(nft_meta_set_eval);

 const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 	[NFTA_META_DREG]	= { .type = NLA_U32 },
 	[NFTA_META_KEY]		= { .type = NLA_U32 },
 	[NFTA_META_SREG]	= { .type = NLA_U32 },
 };
 EXPORT_SYMBOL_GPL(nft_meta_policy);

 int nft_meta_get_init(const struct nft_ctx *ctx,
 		      const struct nft_expr *expr,
 		      const struct nlattr * const tb[])
 {
 	struct nft_meta *priv = nft_expr_priv(expr);
 	int err;

 	priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 	switch (priv->key) {
 	case NFT_META_LEN:
 	case NFT_META_PROTOCOL:
 	case NFT_META_NFPROTO:
 	case NFT_META_L4PROTO:
 	case NFT_META_PRIORITY:
 	case NFT_META_MARK:
 	case NFT_META_IIF:
 	case NFT_META_OIF:
 	case NFT_META_IIFNAME:
 	case NFT_META_OIFNAME:
 	case NFT_META_IIFTYPE:
 	case NFT_META_OIFTYPE:
 	case NFT_META_SKUID:
 	case NFT_META_SKGID:
 #ifdef CONFIG_IP_ROUTE_CLASSID
 	case NFT_META_RTCLASSID:
 #endif
 #ifdef CONFIG_NETWORK_SECMARK
 	case NFT_META_SECMARK:
 #endif
 	case NFT_META_PKTTYPE:
 	case NFT_META_CPU:
 	case NFT_META_IIFGROUP:
 	case NFT_META_OIFGROUP:
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}

 	priv->dreg = ntohl(nla_get_be32(tb[NFTA_META_DREG]));
 	err = nft_validate_output_register(priv->dreg);
 	if (err < 0)
 		return err;

 	err = nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE);
 	if (err < 0)
 		return err;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(nft_meta_get_init);

 int nft_meta_set_init(const struct nft_ctx *ctx,
 		      const struct nft_expr *expr,
 		      const struct nlattr * const tb[])
 {
 	struct nft_meta *priv = nft_expr_priv(expr);
 	int err;

 	priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 	switch (priv->key) {
 	case NFT_META_MARK:
 	case NFT_META_PRIORITY:
 	case NFT_META_NFTRACE:
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}

 	priv->sreg = ntohl(nla_get_be32(tb[NFTA_META_SREG]));
 	err = nft_validate_input_register(priv->sreg);
 	if (err < 0)
 		return err;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(nft_meta_set_init);

 int nft_meta_get_dump(struct sk_buff *skb,
 		      const struct nft_expr *expr)
 {
 	const struct nft_meta *priv = nft_expr_priv(expr);

 	if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 		goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_META_DREG, htonl(priv->dreg)))
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -1;
 }
 EXPORT_SYMBOL_GPL(nft_meta_get_dump);

 int nft_meta_set_dump(struct sk_buff *skb,
 		      const struct nft_expr *expr)
 {
 	const struct nft_meta *priv = nft_expr_priv(expr);

 	if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 		goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_META_SREG, htonl(priv->sreg)))
 		goto nla_put_failure;

 	return 0;

 nla_put_failure:
 	return -1;
 }
 EXPORT_SYMBOL_GPL(nft_meta_set_dump);

 static struct nft_expr_type nft_meta_type;
 static const struct nft_expr_ops nft_meta_get_ops = {
 	.type		= &nft_meta_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 	.eval		= nft_meta_get_eval,
 	.init		= nft_meta_get_init,
 	.dump		= nft_meta_get_dump,
 };

 static const struct nft_expr_ops nft_meta_set_ops = {
 	.type		= &nft_meta_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 	.eval		= nft_meta_set_eval,
 	.init		= nft_meta_set_init,
 	.dump		= nft_meta_set_dump,
 };

 static const struct nft_expr_ops *
 nft_meta_select_ops(const struct nft_ctx *ctx,
 		    const struct nlattr * const tb[])
 {
 	if (tb[NFTA_META_KEY] == NULL)
 		return ERR_PTR(-EINVAL);

 	if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 		return ERR_PTR(-EINVAL);

 	if (tb[NFTA_META_DREG])
 		return &nft_meta_get_ops;

 	if (tb[NFTA_META_SREG])
 		return &nft_meta_set_ops;

 	return ERR_PTR(-EINVAL);
 }

 static struct nft_expr_type nft_meta_type __read_mostly = {
 	.name		= "meta",
 	.select_ops	= &nft_meta_select_ops,
 	.policy		= nft_meta_policy,
 	.maxattr	= NFTA_META_MAX,
 	.owner		= THIS_MODULE,
 };

 static int __init nft_meta_module_init(void)
 {
 	return nft_register_expr(&nft_meta_type);
 }

 static void __exit nft_meta_module_exit(void)
 {
 	nft_unregister_expr(&nft_meta_type);
 }

 module_init(nft_meta_module_init);
 module_exit(nft_meta_module_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 MODULE_ALIAS_NFT_EXPR("meta");
	/*
	* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
	*
	* 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.
	*
	* Development of this code funded by Astaro AG (http://www.astaro.com/)
	*/

	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/netlink.h>
	#include <linux/netfilter.h>
	#include <linux/netfilter/nf_tables.h>
	#include <linux/in.h>
	#include <linux/ip.h>
	#include <linux/ipv6.h>
	#include <linux/smp.h>
	#include <net/dst.h>
	#include <net/sock.h>
	#include <net/tcp_states.h> /* for TCP_TIME_WAIT */
	#include <net/netfilter/nf_tables.h>
	#include <net/netfilter/nft_meta.h>

	void nft_meta_get_eval(const struct nft_expr *expr,
	struct nft_data data[NFT_REG_MAX + 1],
	const struct nft_pktinfo *pkt)
	{
	const struct nft_meta *priv = nft_expr_priv(expr);
	const struct sk_buff *skb = pkt->skb;
	const struct net_device in = pkt->in, out = pkt->out;
	struct nft_data *dest = &data[priv->dreg];

	switch (priv->key) {
	case NFT_META_LEN:
	dest->data[0] = skb->len;
	break;
	case NFT_META_PROTOCOL:
	(__be16 )dest->data = skb->protocol;
	break;
	case NFT_META_NFPROTO:
	dest->data[0] = pkt->ops->pf;
	break;
	case NFT_META_L4PROTO:
	dest->data[0] = pkt->tprot;
	break;
	case NFT_META_PRIORITY:
	dest->data[0] = skb->priority;
	break;
	case NFT_META_MARK:
	dest->data[0] = skb->mark;
	break;
	case NFT_META_IIF:
	if (in == NULL)
	goto err;
	dest->data[0] = in->ifindex;
	break;
	case NFT_META_OIF:
	if (out == NULL)
	goto err;
	dest->data[0] = out->ifindex;
	break;
	case NFT_META_IIFNAME:
	if (in == NULL)
	goto err;
	strncpy((char *)dest->data, in->name, sizeof(dest->data));
	break;
	case NFT_META_OIFNAME:
	if (out == NULL)
	goto err;
	strncpy((char *)dest->data, out->name, sizeof(dest->data));
	break;
	case NFT_META_IIFTYPE:
	if (in == NULL)
	goto err;
	(u16 )dest->data = in->type;
	break;
	case NFT_META_OIFTYPE:
	if (out == NULL)
	goto err;
	(u16 )dest->data = out->type;
	break;
	case NFT_META_SKUID:
	if (skb->sk == NULL \|\| skb->sk->sk_state == TCP_TIME_WAIT)
	goto err;

	read_lock_bh(&skb->sk->sk_callback_lock);
	if (skb->sk->sk_socket == NULL \|\|
	skb->sk->sk_socket->file == NULL) {
	read_unlock_bh(&skb->sk->sk_callback_lock);
	goto err;
	}

	dest->data[0] =
	from_kuid_munged(&init_user_ns,
	skb->sk->sk_socket->file->f_cred->fsuid);
	read_unlock_bh(&skb->sk->sk_callback_lock);
	break;
	case NFT_META_SKGID:
	if (skb->sk == NULL \|\| skb->sk->sk_state == TCP_TIME_WAIT)
	goto err;

	read_lock_bh(&skb->sk->sk_callback_lock);
	if (skb->sk->sk_socket == NULL \|\|
	skb->sk->sk_socket->file == NULL) {
	read_unlock_bh(&skb->sk->sk_callback_lock);
	goto err;
	}
	dest->data[0] =
	from_kgid_munged(&init_user_ns,
	skb->sk->sk_socket->file->f_cred->fsgid);
	read_unlock_bh(&skb->sk->sk_callback_lock);
	break;
	#ifdef CONFIG_IP_ROUTE_CLASSID
	case NFT_META_RTCLASSID: {
	const struct dst_entry *dst = skb_dst(skb);

	if (dst == NULL)
	goto err;
	dest->data[0] = dst->tclassid;
	break;
	}
	#endif
	#ifdef CONFIG_NETWORK_SECMARK
	case NFT_META_SECMARK:
	dest->data[0] = skb->secmark;
	break;
	#endif
	case NFT_META_PKTTYPE:
	if (skb->pkt_type != PACKET_LOOPBACK) {
	dest->data[0] = skb->pkt_type;
	break;
	}

	switch (pkt->ops->pf) {
	case NFPROTO_IPV4:
	if (ipv4_is_multicast(ip_hdr(skb)->daddr))
	dest->data[0] = PACKET_MULTICAST;
	else
	dest->data[0] = PACKET_BROADCAST;
	break;
	case NFPROTO_IPV6:
	if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
	dest->data[0] = PACKET_MULTICAST;
	else
	dest->data[0] = PACKET_BROADCAST;
	break;
	default:
	WARN_ON(1);
	goto err;
	}
	break;
	case NFT_META_CPU:
	dest->data[0] = smp_processor_id();
	break;
	case NFT_META_IIFGROUP:
	if (in == NULL)
	goto err;
	dest->data[0] = in->group;
	break;
	case NFT_META_OIFGROUP:
	if (out == NULL)
	goto err;
	dest->data[0] = out->group;
	break;
	default:
	WARN_ON(1);
	goto err;
	}
	return;

	err:
	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
	}
	EXPORT_SYMBOL_GPL(nft_meta_get_eval);

	void nft_meta_set_eval(const struct nft_expr *expr,
	struct nft_data data[NFT_REG_MAX + 1],
	const struct nft_pktinfo *pkt)
	{
	const struct nft_meta *meta = nft_expr_priv(expr);
	struct sk_buff *skb = pkt->skb;
	u32 value = data[meta->sreg].data[0];

	switch (meta->key) {
	case NFT_META_MARK:
	skb->mark = value;
	break;
	case NFT_META_PRIORITY:
	skb->priority = value;
	break;
	case NFT_META_NFTRACE:
	skb->nf_trace = 1;
	break;
	default:
	WARN_ON(1);
	}
	}
	EXPORT_SYMBOL_GPL(nft_meta_set_eval);

	const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
	[NFTA_META_DREG] = { .type = NLA_U32 },
	[NFTA_META_KEY] = { .type = NLA_U32 },
	[NFTA_META_SREG] = { .type = NLA_U32 },
	};
	EXPORT_SYMBOL_GPL(nft_meta_policy);

	int nft_meta_get_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_meta *priv = nft_expr_priv(expr);
	int err;

	priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
	switch (priv->key) {
	case NFT_META_LEN:
	case NFT_META_PROTOCOL:
	case NFT_META_NFPROTO:
	case NFT_META_L4PROTO:
	case NFT_META_PRIORITY:
	case NFT_META_MARK:
	case NFT_META_IIF:
	case NFT_META_OIF:
	case NFT_META_IIFNAME:
	case NFT_META_OIFNAME:
	case NFT_META_IIFTYPE:
	case NFT_META_OIFTYPE:
	case NFT_META_SKUID:
	case NFT_META_SKGID:
	#ifdef CONFIG_IP_ROUTE_CLASSID
	case NFT_META_RTCLASSID:
	#endif
	#ifdef CONFIG_NETWORK_SECMARK
	case NFT_META_SECMARK:
	#endif
	case NFT_META_PKTTYPE:
	case NFT_META_CPU:
	case NFT_META_IIFGROUP:
	case NFT_META_OIFGROUP:
	break;
	default:
	return -EOPNOTSUPP;
	}

	priv->dreg = ntohl(nla_get_be32(tb[NFTA_META_DREG]));
	err = nft_validate_output_register(priv->dreg);
	if (err < 0)
	return err;

	err = nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE);
	if (err < 0)
	return err;

	return 0;
	}
	EXPORT_SYMBOL_GPL(nft_meta_get_init);

	int nft_meta_set_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_meta *priv = nft_expr_priv(expr);
	int err;

	priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
	switch (priv->key) {
	case NFT_META_MARK:
	case NFT_META_PRIORITY:
	case NFT_META_NFTRACE:
	break;
	default:
	return -EOPNOTSUPP;
	}

	priv->sreg = ntohl(nla_get_be32(tb[NFTA_META_SREG]));
	err = nft_validate_input_register(priv->sreg);
	if (err < 0)
	return err;

	return 0;
	}
	EXPORT_SYMBOL_GPL(nft_meta_set_init);

	int nft_meta_get_dump(struct sk_buff *skb,
	const struct nft_expr *expr)
	{
	const struct nft_meta *priv = nft_expr_priv(expr);

	if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_META_DREG, htonl(priv->dreg)))
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -1;
	}
	EXPORT_SYMBOL_GPL(nft_meta_get_dump);

	int nft_meta_set_dump(struct sk_buff *skb,
	const struct nft_expr *expr)
	{
	const struct nft_meta *priv = nft_expr_priv(expr);

	if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_META_SREG, htonl(priv->sreg)))
	goto nla_put_failure;

	return 0;

	nla_put_failure:
	return -1;
	}
	EXPORT_SYMBOL_GPL(nft_meta_set_dump);

	static struct nft_expr_type nft_meta_type;
	static const struct nft_expr_ops nft_meta_get_ops = {
	.type = &nft_meta_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
	.eval = nft_meta_get_eval,
	.init = nft_meta_get_init,
	.dump = nft_meta_get_dump,
	};

	static const struct nft_expr_ops nft_meta_set_ops = {
	.type = &nft_meta_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
	.eval = nft_meta_set_eval,
	.init = nft_meta_set_init,
	.dump = nft_meta_set_dump,
	};

	static const struct nft_expr_ops *
	nft_meta_select_ops(const struct nft_ctx *ctx,
	const struct nlattr * const tb[])
	{
	if (tb[NFTA_META_KEY] == NULL)
	return ERR_PTR(-EINVAL);

	if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
	return ERR_PTR(-EINVAL);

	if (tb[NFTA_META_DREG])
	return &nft_meta_get_ops;

	if (tb[NFTA_META_SREG])
	return &nft_meta_set_ops;

	return ERR_PTR(-EINVAL);
	}

	static struct nft_expr_type nft_meta_type __read_mostly = {
	.name = "meta",
	.select_ops = &nft_meta_select_ops,
	.policy = nft_meta_policy,
	.maxattr = NFTA_META_MAX,
	.owner = THIS_MODULE,
	};

	static int __init nft_meta_module_init(void)
	{
	return nft_register_expr(&nft_meta_type);
	}

	static void __exit nft_meta_module_exit(void)
	{
	nft_unregister_expr(&nft_meta_type);
	}

	module_init(nft_meta_module_init);
	module_exit(nft_meta_module_exit);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
	MODULE_ALIAS_NFT_EXPR("meta");