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netfilter: tproxy: remove nf_tproxy_core.h

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We've removed nf_tproxy_core.ko, so also remove its header.
The lookup helpers are split and then moved to tproxy target/socket match.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2013-07-29 15:41:53 +02:00 • committed by Pablo Neira Ayuso
commit 93742cf8af
3 changed files with 220 additions and 212 deletions
Download patch file Download diff file Expand all files Collapse all files

206
include/net/netfilter/nf_tproxy_core.h
View file

@ -1,206 +0,0 @@
#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,
saddr, sport,
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
#endif

160
net/netfilter/xt_TPROXY.c
View file

@ -15,7 +15,9 @@
#include <linux/ip.h>
#include <net/checksum.h>
#include <net/udp.h>
#include <net/tcp.h>
#include <net/inet_sock.h>
#include <net/inet_hashtables.h>
#include <linux/inetdevice.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
@ -26,13 +28,18 @@
#define XT_TPROXY_HAVE_IPV6 1
#include <net/if_inet6.h>
#include <net/addrconf.h>
#include <net/inet6_hashtables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#endif
#include <net/netfilter/nf_tproxy_core.h>
#include <linux/netfilter/xt_TPROXY.h>
enum nf_tproxy_lookup_t {
NFT_LOOKUP_LISTENER,
NFT_LOOKUP_ESTABLISHED,
};
static bool tproxy_sk_is_transparent(struct sock *sk)
{
if (sk->sk_state != TCP_TIME_WAIT) {
@ -68,6 +75,157 @@ tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr)
return laddr ? laddr : daddr;
}
/*
* 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).
*
* 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,
const enum nf_tproxy_lookup_t lookup_type)
{
struct sock *sk;
switch (protocol) {
case IPPROTO_TCP:
switch (lookup_type) {
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:
BUG();
}
break;
case IPPROTO_UDP:
sk = udp4_lib_lookup(net, saddr, sport, daddr, dport,
in->ifindex);
if (sk) {
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,
const enum nf_tproxy_lookup_t lookup_type)
{
struct sock *sk;
switch (protocol) {
case IPPROTO_TCP:
switch (lookup_type) {
case NFT_LOOKUP_LISTENER:
sk = inet6_lookup_listener(net, &tcp_hashinfo,
saddr, sport,
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:
BUG();
}
break;
case IPPROTO_UDP:
sk = udp6_lib_lookup(net, saddr, sport, daddr, dport,
in->ifindex);
if (sk) {
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
/**
* tproxy_handle_time_wait4 - handle IPv4 TCP TIME_WAIT reopen redirections
* @skb: The skb being processed.

66
net/netfilter/xt_socket.c
View file

@ -19,12 +19,12 @@
#include <net/icmp.h>
#include <net/sock.h>
#include <net/inet_sock.h>
#include <net/netfilter/nf_tproxy_core.h>
#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
#define XT_SOCKET_HAVE_IPV6 1
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <net/inet6_hashtables.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#endif
@ -101,6 +101,43 @@ extract_icmp4_fields(const struct sk_buff *skb,
return 0;
}
/* "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.
*/
static struct sock *
xt_socket_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)
{
switch (protocol) {
case IPPROTO_TCP:
return __inet_lookup(net, &tcp_hashinfo,
saddr, sport, daddr, dport,
in->ifindex);
case IPPROTO_UDP:
return udp4_lib_lookup(net, saddr, sport, daddr, dport,
in->ifindex);
}
return NULL;
}
static bool
socket_match(const struct sk_buff *skb, struct xt_action_param *par,
const struct xt_socket_mtinfo1 *info)
@ -156,9 +193,9 @@ socket_match(const struct sk_buff *skb, struct xt_action_param *par,
#endif
if (!sk)
sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), protocol,
sk = xt_socket_get_sock_v4(dev_net(skb->dev), protocol,
saddr, daddr, sport, dport,
par->in, NFT_LOOKUP_ANY);
par->in);
if (sk) {
bool wildcard;
bool transparent = true;
@ -261,6 +298,25 @@ extract_icmp6_fields(const struct sk_buff *skb,
return 0;
}
static struct sock *
xt_socket_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)
{
switch (protocol) {
case IPPROTO_TCP:
return inet6_lookup(net, &tcp_hashinfo,
saddr, sport, daddr, dport,
in->ifindex);
case IPPROTO_UDP:
return udp6_lib_lookup(net, saddr, sport, daddr, dport,
in->ifindex);
}
return NULL;
}
static bool
socket_mt6_v1_v2(const struct sk_buff *skb, struct xt_action_param *par)
{
@ -298,9 +354,9 @@ socket_mt6_v1_v2(const struct sk_buff *skb, struct xt_action_param *par)
}
if (!sk)
sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
sk = xt_socket_get_sock_v6(dev_net(skb->dev), tproto,
saddr, daddr, sport, dport,
par->in, NFT_LOOKUP_ANY);
par->in);
if (sk) {
bool wildcard;
bool transparent = true;