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

/*
 * Transparent proxy support for Linux/iptables
 *
 * Copyright (c) 2006-2010 BalaBit IT Ltd.
 * Author: Balazs Scheidler, Krisztian Kovacs
 *
 * 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.
 *
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <net/checksum.h>
#include <net/udp.h>
#include <net/inet_sock.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter/xt_TPROXY.h>

#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#include <net/netfilter/nf_tproxy_core.h>

/**
 * tproxy_handle_time_wait4() - handle IPv4 TCP TIME_WAIT reopen redirections
 * @skb:	The skb being processed.
 * @laddr:	IPv4 address to redirect to or zero.
 * @lport:	TCP port to redirect to or zero.
 * @sk:		The TIME_WAIT TCP socket found by the lookup.
 *
 * We have to handle SYN packets arriving to TIME_WAIT sockets
 * differently: instead of reopening the connection we should rather
 * redirect the new connection to the proxy if there's a listener
 * socket present.
 *
 * tproxy_handle_time_wait4() consumes the socket reference passed in.
 *
 * Returns the listener socket if there's one, the TIME_WAIT socket if
 * no such listener is found, or NULL if the TCP header is incomplete.
 */
static struct sock *
tproxy_handle_time_wait4(struct sk_buff *skb, __be32 laddr, __be16 lport,
			struct sock *sk)
{
	const struct iphdr *iph = ip_hdr(skb);
	struct tcphdr _hdr, *hp;

	hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
	if (hp == NULL) {
		inet_twsk_put(inet_twsk(sk));
		return NULL;
	}

	if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
		/* SYN to a TIME_WAIT socket, we'd rather redirect it
		 * to a listener socket if there's one */
		struct sock *sk2;

		sk2 = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
					    iph->saddr, laddr ? laddr : iph->daddr,
					    hp->source, lport ? lport : hp->dest,
					    skb->dev, NFT_LOOKUP_LISTENER);
		if (sk2) {
			inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
			inet_twsk_put(inet_twsk(sk));
			sk = sk2;
		}
	}

	return sk;
}

/**
 * tproxy_handle_time_wait6() - handle IPv6 TCP TIME_WAIT reopen redirections
 * @skb:	The skb being processed.
 * @tproto:	Transport protocol.
 * @thoff:	Transport protocol header offset.
 * @par:	Iptables target parameters.
 * @sk:		The TIME_WAIT TCP socket found by the lookup.
 *
 * We have to handle SYN packets arriving to TIME_WAIT sockets
 * differently: instead of reopening the connection we should rather
 * redirect the new connection to the proxy if there's a listener
 * socket present.
 *
 * tproxy_handle_time_wait6() consumes the socket reference passed in.
 *
 * Returns the listener socket if there's one, the TIME_WAIT socket if
 * no such listener is found, or NULL if the TCP header is incomplete.
 */
static struct sock *
tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
			 const struct xt_action_param *par,
			 struct sock *sk)
{
	const struct ipv6hdr *iph = ipv6_hdr(skb);
	struct tcphdr _hdr, *hp;
	const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;

	hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
	if (hp == NULL) {
		inet_twsk_put(inet_twsk(sk));
		return NULL;
	}

	if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
		/* SYN to a TIME_WAIT socket, we'd rather redirect it
		 * to a listener socket if there's one */
		struct sock *sk2;

		sk2 = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
					    &iph->saddr,
					    !ipv6_addr_any(&tgi->laddr.in6) ? &tgi->laddr.in6 : &iph->daddr,
					    hp->source,
					    tgi->lport ? tgi->lport : hp->dest,
					    skb->dev, NFT_LOOKUP_LISTENER);
		if (sk2) {
			inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
			inet_twsk_put(inet_twsk(sk));
			sk = sk2;
		}
	}

	return sk;
}

static unsigned int
tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
	   u_int32_t mark_mask, u_int32_t mark_value)
{
	const struct iphdr *iph = ip_hdr(skb);
	struct udphdr _hdr, *hp;
	struct sock *sk;

	hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
	if (hp == NULL)
		return NF_DROP;

	/* check if there's an ongoing connection on the packet
	 * addresses, this happens if the redirect already happened
	 * and the current packet belongs to an already established
	 * connection */
	sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
				   iph->saddr, iph->daddr,
				   hp->source, hp->dest,
				   skb->dev, NFT_LOOKUP_ESTABLISHED);

	/* UDP has no TCP_TIME_WAIT state, so we never enter here */
	if (sk && sk->sk_state == TCP_TIME_WAIT)
		/* reopening a TIME_WAIT connection needs special handling */
		sk = tproxy_handle_time_wait4(skb, laddr, lport, sk);
	else if (!sk)
		/* no, there's no established connection, check if
		 * there's a listener on the redirected addr/port */
		sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
					   iph->saddr, laddr ? laddr : iph->daddr,
					   hp->source, lport ? lport : hp->dest,
					   skb->dev, NFT_LOOKUP_LISTENER);

	/* NOTE: assign_sock consumes our sk reference */
	if (sk && nf_tproxy_assign_sock(skb, sk)) {
		/* This should be in a separate target, but we don't do multiple
		   targets on the same rule yet */
		skb->mark = (skb->mark & ~mark_mask) ^ mark_value;

		pr_debug("redirecting: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
			 iph->protocol, &iph->daddr, ntohs(hp->dest),
			 &laddr, ntohs(lport), skb->mark);
		return NF_ACCEPT;
	}

	pr_debug("no socket, dropping: proto %hhu %08x:%hu -> %08x:%hu, mark: %x\n",
		 iph->protocol, ntohl(iph->daddr), ntohs(hp->dest),
		 ntohl(laddr), ntohs(lport), skb->mark);
	return NF_DROP;
}

static unsigned int
tproxy_tg4_v0(struct sk_buff *skb, const struct xt_action_param *par)
{
	const struct xt_tproxy_target_info *tgi = par->targinfo;

	return tproxy_tg4(skb, tgi->laddr, tgi->lport, tgi->mark_mask, tgi->mark_value);
}

static unsigned int
tproxy_tg4_v1(struct sk_buff *skb, const struct xt_action_param *par)
{
	const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;

	return tproxy_tg4(skb, tgi->laddr.ip, tgi->lport, tgi->mark_mask, tgi->mark_value);
}

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
static unsigned int
tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
{
	const struct ipv6hdr *iph = ipv6_hdr(skb);
	const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
	struct udphdr _hdr, *hp;
	struct sock *sk;
	int thoff;
	int tproto;

	tproto = ipv6_find_hdr(skb, &thoff, -1, NULL);
	if (tproto < 0) {
		pr_debug("unable to find transport header in IPv6 packet, dropping\n");
		return NF_DROP;
	}

	hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
	if (hp == NULL) {
		pr_debug("unable to grab transport header contents in IPv6 packet, dropping\n");
		return NF_DROP;
	}

	/* check if there's an ongoing connection on the packet
	 * addresses, this happens if the redirect already happened
	 * and the current packet belongs to an already established
	 * connection */
	sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
				   &iph->saddr, &iph->daddr,
				   hp->source, hp->dest,
				   par->in, NFT_LOOKUP_ESTABLISHED);

	/* UDP has no TCP_TIME_WAIT state, so we never enter here */
	if (sk && sk->sk_state == TCP_TIME_WAIT)
		/* reopening a TIME_WAIT connection needs special handling */
		sk = tproxy_handle_time_wait6(skb, tproto, thoff, par, sk);
	else if (!sk)
		/* no there's no established connection, check if
		 * there's a listener on the redirected addr/port */
		sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
					   &iph->saddr,
					   !ipv6_addr_any(&tgi->laddr.in6) ? &tgi->laddr.in6 : &iph->daddr,
					   hp->source,
					   tgi->lport ? tgi->lport : hp->dest,
					   par->in, NFT_LOOKUP_LISTENER);

	/* NOTE: assign_sock consumes our sk reference */
	if (sk && nf_tproxy_assign_sock(skb, sk)) {
		/* This should be in a separate target, but we don't do multiple
		   targets on the same rule yet */
		skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;

		pr_debug("redirecting: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
			 tproto, &iph->saddr, ntohs(hp->dest),
			 &tgi->laddr.in6, ntohs(tgi->lport), skb->mark);
		return NF_ACCEPT;
	}

	pr_debug("no socket, dropping: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
		 tproto, &iph->saddr, ntohs(hp->dest),
		 &tgi->laddr.in6, ntohs(tgi->lport), skb->mark);
	return NF_DROP;
}

static int tproxy_tg6_check(const struct xt_tgchk_param *par)
{
	const struct ip6t_ip6 *i = par->entryinfo;

	if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP)
	    && !(i->flags & IP6T_INV_PROTO))
		return 0;

	pr_info("Can be used only in combination with "
		"either -p tcp or -p udp\n");
	return -EINVAL;
}
#endif

static int tproxy_tg4_check(const struct xt_tgchk_param *par)
{
	const struct ipt_ip *i = par->entryinfo;

	if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP)
	    && !(i->invflags & IPT_INV_PROTO))
		return 0;

	pr_info("Can be used only in combination with "
		"either -p tcp or -p udp\n");
	return -EINVAL;
}

static struct xt_target tproxy_tg_reg[] __read_mostly = {
	{
		.name		= "TPROXY",
		.family		= NFPROTO_IPV4,
		.table		= "mangle",
		.target		= tproxy_tg4_v0,
		.revision	= 0,
		.targetsize	= sizeof(struct xt_tproxy_target_info),
		.checkentry	= tproxy_tg4_check,
		.hooks		= 1 << NF_INET_PRE_ROUTING,
		.me		= THIS_MODULE,
	},
	{
		.name		= "TPROXY",
		.family		= NFPROTO_IPV4,
		.table		= "mangle",
		.target		= tproxy_tg4_v1,
		.revision	= 1,
		.targetsize	= sizeof(struct xt_tproxy_target_info_v1),
		.checkentry	= tproxy_tg4_check,
		.hooks		= 1 << NF_INET_PRE_ROUTING,
		.me		= THIS_MODULE,
	},
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
	{
		.name		= "TPROXY",
		.family		= NFPROTO_IPV6,
		.table		= "mangle",
		.target		= tproxy_tg6_v1,
		.revision	= 1,
		.targetsize	= sizeof(struct xt_tproxy_target_info_v1),
		.checkentry	= tproxy_tg6_check,
		.hooks		= 1 << NF_INET_PRE_ROUTING,
		.me		= THIS_MODULE,
	},
#endif

};

static int __init tproxy_tg_init(void)
{
	nf_defrag_ipv4_enable();
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
	nf_defrag_ipv6_enable();
#endif

	return xt_register_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
}

static void __exit tproxy_tg_exit(void)
{
	xt_unregister_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
}

module_init(tproxy_tg_init);
module_exit(tproxy_tg_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
MODULE_DESCRIPTION("Netfilter transparent proxy (TPROXY) target module.");
MODULE_ALIAS("ipt_TPROXY");
MODULE_ALIAS("ip6t_TPROXY");
Commit	Line	Data
e8439270 KK	1	/*
	2	* Transparent proxy support for Linux/iptables
	3	*
6ad78893	4	* Copyright (c) 2006-2010 BalaBit IT Ltd.
e8439270 KK	5	* Author: Balazs Scheidler, Krisztian Kovacs
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*
	11	*/
ff67e4e4	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
e8439270 KK	13	#include <linux/module.h>
	14	#include <linux/skbuff.h>
	15	#include <linux/ip.h>
	16	#include <net/checksum.h>
	17	#include <net/udp.h>
	18	#include <net/inet_sock.h>
	19
	20	#include <linux/netfilter/x_tables.h>
	21	#include <linux/netfilter_ipv4/ip_tables.h>
6ad78893	22	#include <linux/netfilter_ipv6/ip6_tables.h>
e8439270 KK	23	#include <linux/netfilter/xt_TPROXY.h>
	24
	25	#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
6ad78893	26	#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
e8439270 KK	27	#include <net/netfilter/nf_tproxy_core.h>
e8439270 KK	28
106e4c26	29	/**
6ad78893	30	* tproxy_handle_time_wait4() - handle IPv4 TCP TIME_WAIT reopen redirections
106e4c26	31	* @skb: The skb being processed.
6ad78893 BS	32	* @laddr: IPv4 address to redirect to or zero.
6ad78893 BS	33	* @lport: TCP port to redirect to or zero.
106e4c26 BS	34	* @sk: The TIME_WAIT TCP socket found by the lookup.
	35	*
	36	* We have to handle SYN packets arriving to TIME_WAIT sockets
	37	* differently: instead of reopening the connection we should rather
	38	* redirect the new connection to the proxy if there's a listener
	39	* socket present.
	40	*
6ad78893	41	* tproxy_handle_time_wait4() consumes the socket reference passed in.
106e4c26 BS	42	*
	43	* Returns the listener socket if there's one, the TIME_WAIT socket if
	44	* no such listener is found, or NULL if the TCP header is incomplete.
	45	*/
	46	static struct sock *
6ad78893 BS	47	tproxy_handle_time_wait4(struct sk_buff *skb, __be32 laddr, __be16 lport,
6ad78893 BS	48	struct sock *sk)
106e4c26 BS	49	{
106e4c26 BS	50	const struct iphdr *iph = ip_hdr(skb);
106e4c26 BS	51	struct tcphdr _hdr, *hp;
	52
	53	hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
	54	if (hp == NULL) {
	55	inet_twsk_put(inet_twsk(sk));
	56	return NULL;
	57	}
	58
	59	if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
	60	/* SYN to a TIME_WAIT socket, we'd rather redirect it
	61	* to a listener socket if there's one */
	62	struct sock *sk2;
	63
	64	sk2 = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
6ad78893 BS	65	iph->saddr, laddr ? laddr : iph->daddr,
	66	hp->source, lport ? lport : hp->dest,
	67	skb->dev, NFT_LOOKUP_LISTENER);
	68	if (sk2) {
	69	inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
	70	inet_twsk_put(inet_twsk(sk));
	71	sk = sk2;
	72	}
	73	}
	74
	75	return sk;
	76	}
	77
	78	/**
	79	* tproxy_handle_time_wait6() - handle IPv6 TCP TIME_WAIT reopen redirections
	80	* @skb: The skb being processed.
	81	* @tproto: Transport protocol.
	82	* @thoff: Transport protocol header offset.
	83	* @par: Iptables target parameters.
	84	* @sk: The TIME_WAIT TCP socket found by the lookup.
	85	*
	86	* We have to handle SYN packets arriving to TIME_WAIT sockets
	87	* differently: instead of reopening the connection we should rather
	88	* redirect the new connection to the proxy if there's a listener
	89	* socket present.
	90	*
	91	* tproxy_handle_time_wait6() consumes the socket reference passed in.
	92	*
	93	* Returns the listener socket if there's one, the TIME_WAIT socket if
	94	* no such listener is found, or NULL if the TCP header is incomplete.
	95	*/
	96	static struct sock *
	97	tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
	98	const struct xt_action_param *par,
	99	struct sock *sk)
	100	{
	101	const struct ipv6hdr *iph = ipv6_hdr(skb);
	102	struct tcphdr _hdr, *hp;
	103	const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
	104
	105	hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
	106	if (hp == NULL) {
	107	inet_twsk_put(inet_twsk(sk));
	108	return NULL;
	109	}
	110
	111	if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
	112	/* SYN to a TIME_WAIT socket, we'd rather redirect it
	113	* to a listener socket if there's one */
	114	struct sock *sk2;
	115
	116	sk2 = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
	117	&iph->saddr,
	118	!ipv6_addr_any(&tgi->laddr.in6) ? &tgi->laddr.in6 : &iph->daddr,
	119	hp->source,
	120	tgi->lport ? tgi->lport : hp->dest,
	121	skb->dev, NFT_LOOKUP_LISTENER);
106e4c26	122	if (sk2) {
106e4c26 BS	123	inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
	124	inet_twsk_put(inet_twsk(sk));
	125	sk = sk2;
	126	}
	127	}
	128
	129	return sk;
	130	}
	131
e8439270	132	static unsigned int
6ad78893 BS	133	tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
6ad78893 BS	134	u_int32_t mark_mask, u_int32_t mark_value)
e8439270 KK	135	{
e8439270 KK	136	const struct iphdr *iph = ip_hdr(skb);
e8439270 KK	137	struct udphdr _hdr, *hp;
	138	struct sock *sk;
	139
	140	hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
	141	if (hp == NULL)
	142	return NF_DROP;
	143
6ad78893 BS	144	/* check if there's an ongoing connection on the packet
	145	* addresses, this happens if the redirect already happened
	146	* and the current packet belongs to an already established
	147	* connection */
e8439270	148	sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
106e4c26 BS	149	iph->saddr, iph->daddr,
106e4c26 BS	150	hp->source, hp->dest,
6ad78893	151	skb->dev, NFT_LOOKUP_ESTABLISHED);
106e4c26 BS	152
	153	/* UDP has no TCP_TIME_WAIT state, so we never enter here */
	154	if (sk && sk->sk_state == TCP_TIME_WAIT)
6ad78893 BS	155	/* reopening a TIME_WAIT connection needs special handling */
6ad78893 BS	156	sk = tproxy_handle_time_wait4(skb, laddr, lport, sk);
106e4c26	157	else if (!sk)
6ad78893 BS	158	/* no, there's no established connection, check if
6ad78893 BS	159	* there's a listener on the redirected addr/port */
106e4c26	160	sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
6ad78893 BS	161	iph->saddr, laddr ? laddr : iph->daddr,
	162	hp->source, lport ? lport : hp->dest,
	163	skb->dev, NFT_LOOKUP_LISTENER);
	164
	165	/* NOTE: assign_sock consumes our sk reference */
	166	if (sk && nf_tproxy_assign_sock(skb, sk)) {
	167	/* This should be in a separate target, but we don't do multiple
	168	targets on the same rule yet */
	169	skb->mark = (skb->mark & ~mark_mask) ^ mark_value;
	170
	171	pr_debug("redirecting: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
	172	iph->protocol, &iph->daddr, ntohs(hp->dest),
	173	&laddr, ntohs(lport), skb->mark);
	174	return NF_ACCEPT;
	175	}
	176
	177	pr_debug("no socket, dropping: proto %hhu %08x:%hu -> %08x:%hu, mark: %x\n",
	178	iph->protocol, ntohl(iph->daddr), ntohs(hp->dest),
	179	ntohl(laddr), ntohs(lport), skb->mark);
	180	return NF_DROP;
	181	}
	182
	183	static unsigned int
	184	tproxy_tg4_v0(struct sk_buff skb, const struct xt_action_param par)
	185	{
	186	const struct xt_tproxy_target_info *tgi = par->targinfo;
	187
	188	return tproxy_tg4(skb, tgi->laddr, tgi->lport, tgi->mark_mask, tgi->mark_value);
	189	}
	190
	191	static unsigned int
	192	tproxy_tg4_v1(struct sk_buff skb, const struct xt_action_param par)
	193	{
	194	const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
	195
	196	return tproxy_tg4(skb, tgi->laddr.ip, tgi->lport, tgi->mark_mask, tgi->mark_value);
	197	}
	198
	199	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
	200	static unsigned int
	201	tproxy_tg6_v1(struct sk_buff skb, const struct xt_action_param par)
	202	{
	203	const struct ipv6hdr *iph = ipv6_hdr(skb);
	204	const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
	205	struct udphdr _hdr, *hp;
	206	struct sock *sk;
	207	int thoff;
	208	int tproto;
	209
	210	tproto = ipv6_find_hdr(skb, &thoff, -1, NULL);
	211	if (tproto < 0) {
	212	pr_debug("unable to find transport header in IPv6 packet, dropping\n");
	213	return NF_DROP;
	214	}
	215
	216	hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
	217	if (hp == NULL) {
	218	pr_debug("unable to grab transport header contents in IPv6 packet, dropping\n");
	219	return NF_DROP;
	220	}
	221
	222	/* check if there's an ongoing connection on the packet
	223	* addresses, this happens if the redirect already happened
	224	* and the current packet belongs to an already established
225	* connection */
226	sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
227	&iph->saddr, &iph->daddr,
228	hp->source, hp->dest,
229	par->in, NFT_LOOKUP_ESTABLISHED);
230
231	/* UDP has no TCP_TIME_WAIT state, so we never enter here */
232	if (sk && sk->sk_state == TCP_TIME_WAIT)
233	/* reopening a TIME_WAIT connection needs special handling */
234	sk = tproxy_handle_time_wait6(skb, tproto, thoff, par, sk);
235	else if (!sk)
236	/* no there's no established connection, check if
237	* there's a listener on the redirected addr/port */
238	sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
239	&iph->saddr,
240	!ipv6_addr_any(&tgi->laddr.in6) ? &tgi->laddr.in6 : &iph->daddr,
241	hp->source,
242	tgi->lport ? tgi->lport : hp->dest,
106e4c26	243	par->in, NFT_LOOKUP_LISTENER);
e8439270 KK	244
	245	/* NOTE: assign_sock consumes our sk reference */
	246	if (sk && nf_tproxy_assign_sock(skb, sk)) {
	247	/* This should be in a separate target, but we don't do multiple
	248	targets on the same rule yet */
	249	skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;
	250
6ad78893 BS	251	pr_debug("redirecting: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
	252	tproto, &iph->saddr, ntohs(hp->dest),
	253	&tgi->laddr.in6, ntohs(tgi->lport), skb->mark);
e8439270 KK	254	return NF_ACCEPT;
	255	}
	256
6ad78893 BS	257	pr_debug("no socket, dropping: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
	258	tproto, &iph->saddr, ntohs(hp->dest),
	259	&tgi->laddr.in6, ntohs(tgi->lport), skb->mark);
e8439270 KK	260	return NF_DROP;
	261	}
	262
6ad78893 BS	263	static int tproxy_tg6_check(const struct xt_tgchk_param *par)
	264	{
	265	const struct ip6t_ip6 *i = par->entryinfo;
	266
	267	if ((i->proto == IPPROTO_TCP \|\| i->proto == IPPROTO_UDP)
	268	&& !(i->flags & IP6T_INV_PROTO))
	269	return 0;
	270
	271	pr_info("Can be used only in combination with "
	272	"either -p tcp or -p udp\n");
	273	return -EINVAL;
	274	}
	275	#endif
	276
	277	static int tproxy_tg4_check(const struct xt_tgchk_param *par)
e8439270	278	{
af5d6dc2	279	const struct ipt_ip *i = par->entryinfo;
e8439270 KK	280
	281	if ((i->proto == IPPROTO_TCP \|\| i->proto == IPPROTO_UDP)
	282	&& !(i->invflags & IPT_INV_PROTO))
d6b00a53	283	return 0;
e8439270	284
ff67e4e4	285	pr_info("Can be used only in combination with "
e8439270	286	"either -p tcp or -p udp\n");
d6b00a53	287	return -EINVAL;
e8439270 KK	288	}
e8439270 KK	289
6ad78893 BS	290	static struct xt_target tproxy_tg_reg[] __read_mostly = {
	291	{
	292	.name = "TPROXY",
	293	.family = NFPROTO_IPV4,
	294	.table = "mangle",
	295	.target = tproxy_tg4_v0,
	296	.revision = 0,
	297	.targetsize = sizeof(struct xt_tproxy_target_info),
	298	.checkentry = tproxy_tg4_check,
	299	.hooks = 1 << NF_INET_PRE_ROUTING,
	300	.me = THIS_MODULE,
	301	},
	302	{
	303	.name = "TPROXY",
	304	.family = NFPROTO_IPV4,
	305	.table = "mangle",
	306	.target = tproxy_tg4_v1,
	307	.revision = 1,
	308	.targetsize = sizeof(struct xt_tproxy_target_info_v1),
	309	.checkentry = tproxy_tg4_check,
	310	.hooks = 1 << NF_INET_PRE_ROUTING,
	311	.me = THIS_MODULE,
	312	},
	313	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
	314	{
	315	.name = "TPROXY",
	316	.family = NFPROTO_IPV6,
	317	.table = "mangle",
	318	.target = tproxy_tg6_v1,
	319	.revision = 1,
	320	.targetsize = sizeof(struct xt_tproxy_target_info_v1),
	321	.checkentry = tproxy_tg6_check,
	322	.hooks = 1 << NF_INET_PRE_ROUTING,
	323	.me = THIS_MODULE,
	324	},
	325	#endif
	326
e8439270 KK	327	};
	328
	329	static int __init tproxy_tg_init(void)
	330	{
	331	nf_defrag_ipv4_enable();
6ad78893 BS	332	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
	333	nf_defrag_ipv6_enable();
	334	#endif
	335
	336	return xt_register_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
e8439270 KK	337	}
	338
	339	static void __exit tproxy_tg_exit(void)
	340	{
6ad78893	341	xt_unregister_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
e8439270 KK	342	}
	343
	344	module_init(tproxy_tg_init);
	345	module_exit(tproxy_tg_exit);
	346	MODULE_LICENSE("GPL");
6ad78893	347	MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
e8439270 KK	348	MODULE_DESCRIPTION("Netfilter transparent proxy (TPROXY) target module.");
e8439270 KK	349	MODULE_ALIAS("ipt_TPROXY");
6ad78893	350	MODULE_ALIAS("ip6t_TPROXY");