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tproxy: added IPv6 support to the TPROXY target

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This requires a new revision as the old target structure was
IPv4 specific.

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>
Signed-off-by: KOVACS Krisztian <hidden@balabit.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Balazs Scheidler 2010-10-21 16:17:26 +02:00 committed by Patrick McHardy
parent 3b9afb2991
commit 6ad7889327
2 changed files with 235 additions and 40 deletions
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13
include/linux/netfilter/xt_TPROXY.h
View File

@ -1,5 +1,5 @@
#ifndef _XT_TPROXY_H_target
#define _XT_TPROXY_H_target
#ifndef _XT_TPROXY_H
#define _XT_TPROXY_H
/* TPROXY target is capable of marking the packet to perform
* redirection. We can get rid of that whenever we get support for
@ -11,4 +11,11 @@ struct xt_tproxy_target_info {
__be16 lport;
};
#endif /* _XT_TPROXY_H_target */
struct xt_tproxy_target_info_v1 {
u_int32_t mark_mask;
u_int32_t mark_value;
union nf_inet_addr laddr;
__be16 lport;
};
#endif /* _XT_TPROXY_H */

262
net/netfilter/xt_TPROXY.c
View File

@ -1,7 +1,7 @@
/*
* Transparent proxy support for Linux/iptables
*
* Copyright (c) 2006-2007 BalaBit IT Ltd.
* Copyright (c) 2006-2010 BalaBit IT Ltd.
* Author: Balazs Scheidler, Krisztian Kovacs
*
* This program is free software; you can redistribute it and/or modify
@ -19,15 +19,18 @@
#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_wait() - handle TCP TIME_WAIT reopen redirections
* tproxy_handle_time_wait4() - handle IPv4 TCP TIME_WAIT reopen redirections
* @skb: The skb being processed.
* @par: Iptables target parameters.
* @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
@ -35,16 +38,16 @@
* redirect the new connection to the proxy if there's a listener
* socket present.
*
* tproxy_handle_time_wait() consumes the socket reference passed in.
* 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_wait(struct sk_buff *skb, const struct xt_action_param *par, struct sock *sk)
tproxy_handle_time_wait4(struct sk_buff *skb, __be32 laddr, __be16 lport,
struct sock *sk)
{
const struct iphdr *iph = ip_hdr(skb);
const struct xt_tproxy_target_info *tgi = par->targinfo;
struct tcphdr _hdr, *hp;
hp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_hdr), &_hdr);
@ -59,13 +62,64 @@ tproxy_handle_time_wait(struct sk_buff *skb, const struct xt_action_param *par,
struct sock *sk2;
sk2 = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
iph->saddr, tgi->laddr ? tgi->laddr : iph->daddr,
hp->source, tgi->lport ? tgi->lport : hp->dest,
par->in, NFT_LOOKUP_LISTENER);
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) {
/* yeah, there's one, let's kill the TIME_WAIT
* socket and redirect to the listener
*/
inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
inet_twsk_put(inet_twsk(sk));
sk = sk2;
@ -76,10 +130,10 @@ tproxy_handle_time_wait(struct sk_buff *skb, const struct xt_action_param *par,
}
static unsigned int
tproxy_tg(struct sk_buff *skb, const struct xt_action_param *par)
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);
const struct xt_tproxy_target_info *tgi = par->targinfo;
struct udphdr _hdr, *hp;
struct sock *sk;
@ -87,18 +141,105 @@ tproxy_tg(struct sk_buff *skb, const struct xt_action_param *par)
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)
sk = tproxy_handle_time_wait(skb, par, sk);
/* reopening a TIME_WAIT connection needs special handling */
sk = tproxy_handle_time_wait6(skb, tproto, thoff, par, sk);
else if (!sk)
sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
iph->saddr, tgi->laddr ? tgi->laddr : iph->daddr,
hp->source, tgi->lport ? tgi->lport : hp->dest,
/* 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 */
@ -107,19 +248,33 @@ tproxy_tg(struct sk_buff *skb, const struct xt_action_param *par)
targets on the same rule yet */
skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;
pr_debug("redirecting: proto %u %08x:%u -> %08x:%u, mark: %x\n",
iph->protocol, ntohl(iph->daddr), ntohs(hp->dest),
ntohl(tgi->laddr), ntohs(tgi->lport), skb->mark);
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 %u %08x:%u -> %08x:%u, mark: %x\n",
iph->protocol, ntohl(iph->daddr), ntohs(hp->dest),
ntohl(tgi->laddr), ntohs(tgi->lport), skb->mark);
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_tg_check(const struct xt_tgchk_param *par)
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;
@ -132,31 +287,64 @@ static int tproxy_tg_check(const struct xt_tgchk_param *par)
return -EINVAL;
}
static struct xt_target tproxy_tg_reg __read_mostly = {
.name = "TPROXY",
.family = NFPROTO_IPV4,
.table = "mangle",
.target = tproxy_tg,
.targetsize = sizeof(struct xt_tproxy_target_info),
.checkentry = tproxy_tg_check,
.hooks = 1 << NF_INET_PRE_ROUTING,
.me = THIS_MODULE,
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();
return xt_register_target(&tproxy_tg_reg);
#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_target(&tproxy_tg_reg);
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("Krisztian Kovacs");
MODULE_AUTHOR("Balazs Scheidler, Krisztian Kovacs");
MODULE_DESCRIPTION("Netfilter transparent proxy (TPROXY) target module.");
MODULE_ALIAS("ipt_TPROXY");
MODULE_ALIAS("ip6t_TPROXY");