[linux.git] / net / netfilter / xt_TEE.c

/*
 *	"TEE" target extension for Xtables
 *	Copyright © Sebastian Claßen, 2007
 *	Jan Engelhardt, 2007-2010
 *
 *	based on ipt_ROUTE.c from Cédric de Launois
 *	<[email protected]>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	version 2 or later, as published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/route.h>
#include <linux/netfilter/x_tables.h>
#include <net/route.h>
#include <net/netfilter/ipv4/nf_dup_ipv4.h>
#include <net/netfilter/ipv6/nf_dup_ipv6.h>
#include <linux/netfilter/xt_TEE.h>

struct xt_tee_priv {
	struct notifier_block	notifier;
	struct xt_tee_tginfo	*tginfo;
	int			oif;
};

static const union nf_inet_addr tee_zero_address;

static unsigned int
tee_tg4(struct sk_buff *skb, const struct xt_action_param *par)
{
	const struct xt_tee_tginfo *info = par->targinfo;
	int oif = info->priv ? info->priv->oif : 0;

	nf_dup_ipv4(xt_net(par), skb, xt_hooknum(par), &info->gw.in, oif);

	return XT_CONTINUE;
}

#if IS_ENABLED(CONFIG_IPV6)
static unsigned int
tee_tg6(struct sk_buff *skb, const struct xt_action_param *par)
{
	const struct xt_tee_tginfo *info = par->targinfo;
	int oif = info->priv ? info->priv->oif : 0;

	nf_dup_ipv6(xt_net(par), skb, xt_hooknum(par), &info->gw.in6, oif);

	return XT_CONTINUE;
}
#endif

static int tee_netdev_event(struct notifier_block *this, unsigned long event,
			    void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
	struct xt_tee_priv *priv;

	priv = container_of(this, struct xt_tee_priv, notifier);
	switch (event) {
	case NETDEV_REGISTER:
		if (!strcmp(dev->name, priv->tginfo->oif))
			priv->oif = dev->ifindex;
		break;
	case NETDEV_UNREGISTER:
		if (dev->ifindex == priv->oif)
			priv->oif = -1;
		break;
	case NETDEV_CHANGENAME:
		if (!strcmp(dev->name, priv->tginfo->oif))
			priv->oif = dev->ifindex;
		else if (dev->ifindex == priv->oif)
			priv->oif = -1;
		break;
	}

	return NOTIFY_DONE;
}

static int tee_tg_check(const struct xt_tgchk_param *par)
{
	struct xt_tee_tginfo *info = par->targinfo;
	struct xt_tee_priv *priv;

	/* 0.0.0.0 and :: not allowed */
	if (memcmp(&info->gw, &tee_zero_address,
		   sizeof(tee_zero_address)) == 0)
		return -EINVAL;

	if (info->oif[0]) {
		int ret;

		if (info->oif[sizeof(info->oif)-1] != '\0')
			return -EINVAL;

		priv = kzalloc(sizeof(*priv), GFP_KERNEL);
		if (priv == NULL)
			return -ENOMEM;

		priv->tginfo  = info;
		priv->oif     = -1;
		priv->notifier.notifier_call = tee_netdev_event;
		info->priv    = priv;

		ret = register_netdevice_notifier(&priv->notifier);
		if (ret) {
			kfree(priv);
			return ret;
		}
	} else
		info->priv = NULL;

	static_key_slow_inc(&xt_tee_enabled);
	return 0;
}

static void tee_tg_destroy(const struct xt_tgdtor_param *par)
{
	struct xt_tee_tginfo *info = par->targinfo;

	if (info->priv) {
		unregister_netdevice_notifier(&info->priv->notifier);
		kfree(info->priv);
	}
	static_key_slow_dec(&xt_tee_enabled);
}

static struct xt_target tee_tg_reg[] __read_mostly = {
	{
		.name       = "TEE",
		.revision   = 1,
		.family     = NFPROTO_IPV4,
		.target     = tee_tg4,
		.targetsize = sizeof(struct xt_tee_tginfo),
		.usersize   = offsetof(struct xt_tee_tginfo, priv),
		.checkentry = tee_tg_check,
		.destroy    = tee_tg_destroy,
		.me         = THIS_MODULE,
	},
#if IS_ENABLED(CONFIG_IPV6)
	{
		.name       = "TEE",
		.revision   = 1,
		.family     = NFPROTO_IPV6,
		.target     = tee_tg6,
		.targetsize = sizeof(struct xt_tee_tginfo),
		.usersize   = offsetof(struct xt_tee_tginfo, priv),
		.checkentry = tee_tg_check,
		.destroy    = tee_tg_destroy,
		.me         = THIS_MODULE,
	},
#endif
};

static int __init tee_tg_init(void)
{
	return xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
}

static void __exit tee_tg_exit(void)
{
	xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
}

module_init(tee_tg_init);
module_exit(tee_tg_exit);
MODULE_AUTHOR("Sebastian Claßen <[email protected]>");
MODULE_AUTHOR("Jan Engelhardt <[email protected]>");
MODULE_DESCRIPTION("Xtables: Reroute packet copy");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_TEE");
MODULE_ALIAS("ip6t_TEE");
Commit	Line	Data
e281b198 JE	1	/*
	2	* "TEE" target extension for Xtables
	3	* Copyright © Sebastian Claßen, 2007
	4	* Jan Engelhardt, 2007-2010
	5	*
	6	* based on ipt_ROUTE.c from Cédric de Launois
	7	* <[email protected]>
	8	*
	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License
	11	* version 2 or later, as published by the Free Software Foundation.
	12	*/
e281b198	13	#include <linux/module.h>
e281b198	14	#include <linux/skbuff.h>
bbde9fc1	15	#include <linux/route.h>
e281b198	16	#include <linux/netfilter/x_tables.h>
bbde9fc1 PNA	17	#include <net/route.h>
	18	#include <net/netfilter/ipv4/nf_dup_ipv4.h>
	19	#include <net/netfilter/ipv6/nf_dup_ipv6.h>
e281b198	20	#include <linux/netfilter/xt_TEE.h>
e281b198	21
22265a5c PM	22	struct xt_tee_priv {
	23	struct notifier_block notifier;
	24	struct xt_tee_tginfo *tginfo;
	25	int oif;
	26	};
	27
e281b198 JE	28	static const union nf_inet_addr tee_zero_address;
e281b198 JE	29
e281b198	30	static unsigned int
4b560b44	31	tee_tg4(struct sk_buff skb, const struct xt_action_param par)
e281b198 JE	32	{
e281b198 JE	33	const struct xt_tee_tginfo *info = par->targinfo;
45efccdb	34	int oif = info->priv ? info->priv->oif : 0;
e281b198	35
613dbd95	36	nf_dup_ipv4(xt_net(par), skb, xt_hooknum(par), &info->gw.in, oif);
e281b198	37
e281b198 JE	38	return XT_CONTINUE;
	39	}
	40
08a7f5d3	41	#if IS_ENABLED(CONFIG_IPV6)
e281b198	42	static unsigned int
4b560b44	43	tee_tg6(struct sk_buff skb, const struct xt_action_param par)
e281b198 JE	44	{
e281b198 JE	45	const struct xt_tee_tginfo *info = par->targinfo;
45efccdb	46	int oif = info->priv ? info->priv->oif : 0;
e281b198	47
613dbd95	48	nf_dup_ipv6(xt_net(par), skb, xt_hooknum(par), &info->gw.in6, oif);
e281b198	49
e281b198 JE	50	return XT_CONTINUE;
e281b198 JE	51	}
dfd56b8b	52	#endif
e281b198	53
22265a5c PM	54	static int tee_netdev_event(struct notifier_block *this, unsigned long event,
	55	void *ptr)
	56	{
351638e7	57	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
22265a5c PM	58	struct xt_tee_priv *priv;
	59
	60	priv = container_of(this, struct xt_tee_priv, notifier);
	61	switch (event) {
	62	case NETDEV_REGISTER:
	63	if (!strcmp(dev->name, priv->tginfo->oif))
	64	priv->oif = dev->ifindex;
	65	break;
	66	case NETDEV_UNREGISTER:
	67	if (dev->ifindex == priv->oif)
	68	priv->oif = -1;
	69	break;
	70	case NETDEV_CHANGENAME:
	71	if (!strcmp(dev->name, priv->tginfo->oif))
	72	priv->oif = dev->ifindex;
	73	else if (dev->ifindex == priv->oif)
	74	priv->oif = -1;
	75	break;
	76	}
	77
	78	return NOTIFY_DONE;
	79	}
	80
e281b198 JE	81	static int tee_tg_check(const struct xt_tgchk_param *par)
e281b198 JE	82	{
22265a5c PM	83	struct xt_tee_tginfo *info = par->targinfo;
22265a5c PM	84	struct xt_tee_priv *priv;
e281b198	85
e281b198	86	/* 0.0.0.0 and :: not allowed */
22265a5c PM	87	if (memcmp(&info->gw, &tee_zero_address,
	88	sizeof(tee_zero_address)) == 0)
	89	return -EINVAL;
	90
	91	if (info->oif[0]) {
4e6577de GF	92	int ret;
4e6577de GF	93
22265a5c PM	94	if (info->oif[sizeof(info->oif)-1] != '\0')
	95	return -EINVAL;
	96
	97	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	98	if (priv == NULL)
	99	return -ENOMEM;
	100
	101	priv->tginfo = info;
	102	priv->oif = -1;
	103	priv->notifier.notifier_call = tee_netdev_event;
	104	info->priv = priv;
	105
4e6577de GF	106	ret = register_netdevice_notifier(&priv->notifier);
	107	if (ret) {
	108	kfree(priv);
	109	return ret;
	110	}
22265a5c PM	111	} else
	112	info->priv = NULL;
	113
dcebd315	114	static_key_slow_inc(&xt_tee_enabled);
22265a5c PM	115	return 0;
	116	}
	117
	118	static void tee_tg_destroy(const struct xt_tgdtor_param *par)
	119	{
	120	struct xt_tee_tginfo *info = par->targinfo;
	121
	122	if (info->priv) {
	123	unregister_netdevice_notifier(&info->priv->notifier);
	124	kfree(info->priv);
	125	}
dcebd315	126	static_key_slow_dec(&xt_tee_enabled);
e281b198 JE	127	}
	128
	129	static struct xt_target tee_tg_reg[] __read_mostly = {
	130	{
	131	.name = "TEE",
	132	.revision = 1,
	133	.family = NFPROTO_IPV4,
	134	.target = tee_tg4,
	135	.targetsize = sizeof(struct xt_tee_tginfo),
ec231890	136	.usersize = offsetof(struct xt_tee_tginfo, priv),
e281b198	137	.checkentry = tee_tg_check,
22265a5c	138	.destroy = tee_tg_destroy,
e281b198 JE	139	.me = THIS_MODULE,
e281b198 JE	140	},
08a7f5d3	141	#if IS_ENABLED(CONFIG_IPV6)
e281b198 JE	142	{
	143	.name = "TEE",
	144	.revision = 1,
	145	.family = NFPROTO_IPV6,
	146	.target = tee_tg6,
	147	.targetsize = sizeof(struct xt_tee_tginfo),
ec231890	148	.usersize = offsetof(struct xt_tee_tginfo, priv),
e281b198	149	.checkentry = tee_tg_check,
22265a5c	150	.destroy = tee_tg_destroy,
e281b198 JE	151	.me = THIS_MODULE,
	152	},
	153	#endif
	154	};
	155
	156	static int __init tee_tg_init(void)
	157	{
	158	return xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
	159	}
	160
	161	static void __exit tee_tg_exit(void)
	162	{
	163	xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
	164	}
	165
	166	module_init(tee_tg_init);
	167	module_exit(tee_tg_exit);
	168	MODULE_AUTHOR("Sebastian Claßen <[email protected]>");
	169	MODULE_AUTHOR("Jan Engelhardt <[email protected]>");
	170	MODULE_DESCRIPTION("Xtables: Reroute packet copy");
	171	MODULE_LICENSE("GPL");
	172	MODULE_ALIAS("ipt_TEE");
	173	MODULE_ALIAS("ip6t_TEE");