[mirror_ubuntu-artful-kernel.git] / include / net / netfilter / nf_tproxy_core.h

#ifndef _NF_TPROXY_CORE_H
#define _NF_TPROXY_CORE_H

#include <linux/types.h>
#include <linux/in.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/inet_hashtables.h>
#include <net/inet6_hashtables.h>
#include <net/tcp.h>

#define NFT_LOOKUP_ANY         0
#define NFT_LOOKUP_LISTENER    1
#define NFT_LOOKUP_ESTABLISHED 2

/* look up and get a reference to a matching socket */


/* This function is used by the 'TPROXY' target and the 'socket'
 * match. The following lookups are supported:
 *
 * Explicit TProxy target rule
 * ===========================
 *
 * This is used when the user wants to intercept a connection matching
 * an explicit iptables rule. In this case the sockets are assumed
 * matching in preference order:
 *
 *   - match: if there's a fully established connection matching the
 *     _packet_ tuple, it is returned, assuming the redirection
 *     already took place and we process a packet belonging to an
 *     established connection
 *
 *   - match: if there's a listening socket matching the redirection
 *     (e.g. on-port & on-ip of the connection), it is returned,
 *     regardless if it was bound to 0.0.0.0 or an explicit
 *     address. The reasoning is that if there's an explicit rule, it
 *     does not really matter if the listener is bound to an interface
 *     or to 0. The user already stated that he wants redirection
 *     (since he added the rule).
 *
 * "socket" match based redirection (no specific rule)
 * ===================================================
 *
 * There are connections with dynamic endpoints (e.g. FTP data
 * connection) that the user is unable to add explicit rules
 * for. These are taken care of by a generic "socket" rule. It is
 * assumed that the proxy application is trusted to open such
 * connections without explicit iptables rule (except of course the
 * generic 'socket' rule). In this case the following sockets are
 * matched in preference order:
 *
 *   - match: if there's a fully established connection matching the
 *     _packet_ tuple
 *
 *   - match: if there's a non-zero bound listener (possibly with a
 *     non-local address) We don't accept zero-bound listeners, since
 *     then local services could intercept traffic going through the
 *     box.
 *
 * Please note that there's an overlap between what a TPROXY target
 * and a socket match will match. Normally if you have both rules the
 * "socket" match will be the first one, effectively all packets
 * belonging to established connections going through that one.
 */
static inline struct sock *
nf_tproxy_get_sock_v4(struct net *net, const u8 protocol,
		      const __be32 saddr, const __be32 daddr,
		      const __be16 sport, const __be16 dport,
		      const struct net_device *in, int lookup_type)
{
	struct sock *sk;

	/* look up socket */
	switch (protocol) {
	case IPPROTO_TCP:
		switch (lookup_type) {
		case NFT_LOOKUP_ANY:
			sk = __inet_lookup(net, &tcp_hashinfo,
					   saddr, sport, daddr, dport,
					   in->ifindex);
			break;
		case NFT_LOOKUP_LISTENER:
			sk = inet_lookup_listener(net, &tcp_hashinfo,
						    saddr, sport,
						    daddr, dport,
						    in->ifindex);

			/* NOTE: we return listeners even if bound to
			 * 0.0.0.0, those are filtered out in
			 * xt_socket, since xt_TPROXY needs 0 bound
			 * listeners too */

			break;
		case NFT_LOOKUP_ESTABLISHED:
			sk = inet_lookup_established(net, &tcp_hashinfo,
						    saddr, sport, daddr, dport,
						    in->ifindex);
			break;
		default:
			WARN_ON(1);
			sk = NULL;
			break;
		}
		break;
	case IPPROTO_UDP:
		sk = udp4_lib_lookup(net, saddr, sport, daddr, dport,
				     in->ifindex);
		if (sk && lookup_type != NFT_LOOKUP_ANY) {
			int connected = (sk->sk_state == TCP_ESTABLISHED);
			int wildcard = (inet_sk(sk)->inet_rcv_saddr == 0);

			/* NOTE: we return listeners even if bound to
			 * 0.0.0.0, those are filtered out in
			 * xt_socket, since xt_TPROXY needs 0 bound
			 * listeners too */
			if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
			    (lookup_type == NFT_LOOKUP_LISTENER && connected)) {
				sock_put(sk);
				sk = NULL;
			}
		}
		break;
	default:
		WARN_ON(1);
		sk = NULL;
	}

	pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, lookup type: %d, sock %p\n",
		 protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), lookup_type, sk);

	return sk;
}

#if IS_ENABLED(CONFIG_IPV6)
static inline struct sock *
nf_tproxy_get_sock_v6(struct net *net, const u8 protocol,
		      const struct in6_addr *saddr, const struct in6_addr *daddr,
		      const __be16 sport, const __be16 dport,
		      const struct net_device *in, int lookup_type)
{
	struct sock *sk;

	/* look up socket */
	switch (protocol) {
	case IPPROTO_TCP:
		switch (lookup_type) {
		case NFT_LOOKUP_ANY:
			sk = inet6_lookup(net, &tcp_hashinfo,
					  saddr, sport, daddr, dport,
					  in->ifindex);
			break;
		case NFT_LOOKUP_LISTENER:
			sk = inet6_lookup_listener(net, &tcp_hashinfo,
						   daddr, ntohs(dport),
						   in->ifindex);

			/* NOTE: we return listeners even if bound to
			 * 0.0.0.0, those are filtered out in
			 * xt_socket, since xt_TPROXY needs 0 bound
			 * listeners too */

			break;
		case NFT_LOOKUP_ESTABLISHED:
			sk = __inet6_lookup_established(net, &tcp_hashinfo,
							saddr, sport, daddr, ntohs(dport),
							in->ifindex);
			break;
		default:
			WARN_ON(1);
			sk = NULL;
			break;
		}
		break;
	case IPPROTO_UDP:
		sk = udp6_lib_lookup(net, saddr, sport, daddr, dport,
				     in->ifindex);
		if (sk && lookup_type != NFT_LOOKUP_ANY) {
			int connected = (sk->sk_state == TCP_ESTABLISHED);
			int wildcard = ipv6_addr_any(&inet6_sk(sk)->rcv_saddr);

			/* NOTE: we return listeners even if bound to
			 * 0.0.0.0, those are filtered out in
			 * xt_socket, since xt_TPROXY needs 0 bound
			 * listeners too */
			if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
			    (lookup_type == NFT_LOOKUP_LISTENER && connected)) {
				sock_put(sk);
				sk = NULL;
			}
		}
		break;
	default:
		WARN_ON(1);
		sk = NULL;
	}

	pr_debug("tproxy socket lookup: proto %u %pI6:%u -> %pI6:%u, lookup type: %d, sock %p\n",
		 protocol, saddr, ntohs(sport), daddr, ntohs(dport), lookup_type, sk);

	return sk;
}
#endif

/* assign a socket to the skb -- consumes sk */
void
nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk);

#endif
Commit	Line	Data
9ad2d745 KK	1	#ifndef _NF_TPROXY_CORE_H
	2	#define _NF_TPROXY_CORE_H
	3
	4	#include <linux/types.h>
	5	#include <linux/in.h>
	6	#include <linux/skbuff.h>
	7	#include <net/sock.h>
3b9afb29 BS	8	#include <net/inet_hashtables.h>
3b9afb29 BS	9	#include <net/inet6_hashtables.h>
9ad2d745 KK	10	#include <net/tcp.h>
9ad2d745 KK	11
106e4c26 BS	12	#define NFT_LOOKUP_ANY 0
	13	#define NFT_LOOKUP_LISTENER 1
	14	#define NFT_LOOKUP_ESTABLISHED 2
	15
9ad2d745	16	/* look up and get a reference to a matching socket */
6006db84 BS	17
	18
	19	/* This function is used by the 'TPROXY' target and the 'socket'
	20	* match. The following lookups are supported:
	21	*
	22	* Explicit TProxy target rule
	23	* ===========================
	24	*
	25	* This is used when the user wants to intercept a connection matching
	26	* an explicit iptables rule. In this case the sockets are assumed
	27	* matching in preference order:
	28	*
	29	* - match: if there's a fully established connection matching the
	30	* _packet_ tuple, it is returned, assuming the redirection
	31	* already took place and we process a packet belonging to an
	32	* established connection
	33	*
	34	* - match: if there's a listening socket matching the redirection
	35	* (e.g. on-port & on-ip of the connection), it is returned,
	36	* regardless if it was bound to 0.0.0.0 or an explicit
	37	* address. The reasoning is that if there's an explicit rule, it
	38	* does not really matter if the listener is bound to an interface
	39	* or to 0. The user already stated that he wants redirection
	40	* (since he added the rule).
	41	*
	42	* "socket" match based redirection (no specific rule)
	43	* ===================================================
	44	*
	45	* There are connections with dynamic endpoints (e.g. FTP data
	46	* connection) that the user is unable to add explicit rules
	47	* for. These are taken care of by a generic "socket" rule. It is
	48	* assumed that the proxy application is trusted to open such
	49	* connections without explicit iptables rule (except of course the
	50	* generic 'socket' rule). In this case the following sockets are
	51	* matched in preference order:
	52	*
	53	* - match: if there's a fully established connection matching the
	54	* _packet_ tuple
	55	*
	56	* - match: if there's a non-zero bound listener (possibly with a
	57	* non-local address) We don't accept zero-bound listeners, since
	58	* then local services could intercept traffic going through the
	59	* box.
	60	*
	61	* Please note that there's an overlap between what a TPROXY target
	62	* and a socket match will match. Normally if you have both rules the
	63	* "socket" match will be the first one, effectively all packets
	64	* belonging to established connections going through that one.
	65	*/
	66	static inline struct sock *
9ad2d745 KK	67	nf_tproxy_get_sock_v4(struct net *net, const u8 protocol,
	68	const __be32 saddr, const __be32 daddr,
	69	const __be16 sport, const __be16 dport,
6006db84 BS	70	const struct net_device *in, int lookup_type)
	71	{
	72	struct sock *sk;
	73
	74	/* look up socket */
	75	switch (protocol) {
	76	case IPPROTO_TCP:
	77	switch (lookup_type) {
	78	case NFT_LOOKUP_ANY:
	79	sk = __inet_lookup(net, &tcp_hashinfo,
	80	saddr, sport, daddr, dport,
	81	in->ifindex);
	82	break;
	83	case NFT_LOOKUP_LISTENER:
	84	sk = inet_lookup_listener(net, &tcp_hashinfo,
da5e3630	85	saddr, sport,
6006db84 BS	86	daddr, dport,
	87	in->ifindex);
	88
	89	/* NOTE: we return listeners even if bound to
	90	* 0.0.0.0, those are filtered out in
	91	* xt_socket, since xt_TPROXY needs 0 bound
	92	* listeners too */
	93
	94	break;
	95	case NFT_LOOKUP_ESTABLISHED:
	96	sk = inet_lookup_established(net, &tcp_hashinfo,
	97	saddr, sport, daddr, dport,
	98	in->ifindex);
	99	break;
	100	default:
	101	WARN_ON(1);
	102	sk = NULL;
	103	break;
	104	}
	105	break;
	106	case IPPROTO_UDP:
	107	sk = udp4_lib_lookup(net, saddr, sport, daddr, dport,
	108	in->ifindex);
	109	if (sk && lookup_type != NFT_LOOKUP_ANY) {
	110	int connected = (sk->sk_state == TCP_ESTABLISHED);
	111	int wildcard = (inet_sk(sk)->inet_rcv_saddr == 0);
	112
	113	/* NOTE: we return listeners even if bound to
	114	* 0.0.0.0, those are filtered out in
	115	* xt_socket, since xt_TPROXY needs 0 bound
	116	* listeners too */
	117	if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected \|\| wildcard)) \|\|
	118	(lookup_type == NFT_LOOKUP_LISTENER && connected)) {
	119	sock_put(sk);
	120	sk = NULL;
	121	}
	122	}
	123	break;
	124	default:
	125	WARN_ON(1);
	126	sk = NULL;
	127	}
	128
	129	pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, lookup type: %d, sock %p\n",
	130	protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), lookup_type, sk);
	131
	132	return sk;
	133	}
	134
dfd56b8b	135	#if IS_ENABLED(CONFIG_IPV6)
3b9afb29 BS	136	static inline struct sock *
	137	nf_tproxy_get_sock_v6(struct net *net, const u8 protocol,
	138	const struct in6_addr saddr, const struct in6_addr daddr,
	139	const __be16 sport, const __be16 dport,
	140	const struct net_device *in, int lookup_type)
	141	{
	142	struct sock *sk;
	143
	144	/* look up socket */
	145	switch (protocol) {
	146	case IPPROTO_TCP:
	147	switch (lookup_type) {
	148	case NFT_LOOKUP_ANY:
	149	sk = inet6_lookup(net, &tcp_hashinfo,
	150	saddr, sport, daddr, dport,
	151	in->ifindex);
	152	break;
	153	case NFT_LOOKUP_LISTENER:
	154	sk = inet6_lookup_listener(net, &tcp_hashinfo,
	155	daddr, ntohs(dport),
	156	in->ifindex);
	157
	158	/* NOTE: we return listeners even if bound to
	159	* 0.0.0.0, those are filtered out in
	160	* xt_socket, since xt_TPROXY needs 0 bound
	161	* listeners too */
	162
	163	break;
	164	case NFT_LOOKUP_ESTABLISHED:
	165	sk = __inet6_lookup_established(net, &tcp_hashinfo,
	166	saddr, sport, daddr, ntohs(dport),
	167	in->ifindex);
	168	break;
	169	default:
	170	WARN_ON(1);
	171	sk = NULL;
	172	break;
	173	}
	174	break;
	175	case IPPROTO_UDP:
	176	sk = udp6_lib_lookup(net, saddr, sport, daddr, dport,
	177	in->ifindex);
	178	if (sk && lookup_type != NFT_LOOKUP_ANY) {
	179	int connected = (sk->sk_state == TCP_ESTABLISHED);
	180	int wildcard = ipv6_addr_any(&inet6_sk(sk)->rcv_saddr);
	181
	182	/* NOTE: we return listeners even if bound to
	183	* 0.0.0.0, those are filtered out in
	184	* xt_socket, since xt_TPROXY needs 0 bound
	185	* listeners too */
	186	if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected \|\| wildcard)) \|\|
	187	(lookup_type == NFT_LOOKUP_LISTENER && connected)) {
	188	sock_put(sk);
	189	sk = NULL;
	190	}
	191	}
	192	break;
	193	default:
	194	WARN_ON(1);
	195	sk = NULL;
	196	}
	197
	198	pr_debug("tproxy socket lookup: proto %u %pI6:%u -> %pI6:%u, lookup type: %d, sock %p\n",
	199	protocol, saddr, ntohs(sport), daddr, ntohs(dport), lookup_type, sk);
200
201	return sk;
202	}
203	#endif
9ad2d745	204
9ad2d745	205	/* assign a socket to the skb -- consumes sk */
d503b30b	206	void
9ad2d745 KK	207	nf_tproxy_assign_sock(struct sk_buff skb, struct sock sk);
	208
	209	#endif