From: Balazs Scheidler <bazsi@xxxxxxxxxx>
This requires a new revision as the old target structure was
IPv4 specific.
Signed-off-by: Balazs Scheidler <bazsi@xxxxxxxxxx>
Signed-off-by: KOVACS Krisztian <hidden@xxxxxxxxxx>
---
include/linux/netfilter/xt_TPROXY.h | 15 +-
net/netfilter/xt_TPROXY.c | 262 ++++++++++++++++++++++++++++++-----
2 files changed, 236 insertions(+), 41 deletions(-)
diff --git a/include/linux/netfilter/xt_TPROXY.h b/include/linux/netfilter/xt_TPROXY.h
index 152e8f9..7b4e06d 100644
--- a/include/linux/netfilter/xt_TPROXY.h
+++ b/include/linux/netfilter/xt_TPROXY.h
@@ -1,14 +1,21 @@
-#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
* mutliple targets in the same rule. */
-struct xt_tproxy_target_info {
+struct xt_tproxy_target_info_v0 {
u_int32_t mark_mask;
u_int32_t mark_value;
__be32 laddr;
__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 */
diff --git a/net/netfilter/xt_TPROXY.c b/net/netfilter/xt_TPROXY.c
index 67cbed8..6ce76d6 100644
--- a/net/netfilter/xt_TPROXY.c
+++ b/net/netfilter/xt_TPROXY.c
@@ -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;
@@ -87,39 +141,140 @@ 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,
- par->in, NFT_LOOKUP_ESTABLISHED);
+ 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)
- sk = tproxy_handle_time_wait(skb, par, sk);
+ /* 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, 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);
/* 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;
+ skb->mark = (skb->mark & ~mark_mask) ^ 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 %u %pI4:%u -> %pI4:%u, mark: %x\n",
+ iph->protocol, &iph->daddr, ntohs(hp->dest),
+ &laddr, ntohs(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);
+ 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_v0 *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 %u %pI6:%u -> %pI6:%u, 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 %pI6:%u -> %pI6:%u, 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 = AF_INET,
- .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_v0),
+ .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");
--
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