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Date: Mon, 05 Mar 2007 16:46:52 +0100
From: KOVACS Krisztian <hidden@...abit.hu>
To: netdev@...r.kernel.org
Subject: [PATCH/RFC 12/13] iptables TPROXY target
The TPROXY target implements redirection of non-local TCP/UDP traffic
to local sockets. It is simply a wrapper around functionality exported
from iptable_tproxy.
Signed-off-by: KOVACS Krisztian <hidden@...abit.hu>
---
include/linux/netfilter_ipv4/ipt_TPROXY.h | 9 +++
net/ipv4/netfilter/Kconfig | 11 +++
net/ipv4/netfilter/Makefile | 1
net/ipv4/netfilter/ipt_TPROXY.c | 92 +++++++++++++++++++++++++++++
4 files changed, 113 insertions(+), 0 deletions(-)
diff --git a/include/linux/netfilter_ipv4/ipt_TPROXY.h b/include/linux/netfilter_ipv4/ipt_TPROXY.h
new file mode 100644
index 0000000..d05c956
--- /dev/null
+++ b/include/linux/netfilter_ipv4/ipt_TPROXY.h
@@ -0,0 +1,9 @@
+#ifndef _IPT_TPROXY_H_target
+#define _IPT_TPROXY_H_target
+
+struct ipt_tproxy_target_info {
+ u_int16_t lport;
+ u_int32_t laddr;
+};
+
+#endif
diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 17c3ec8..ecd8da5 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -638,6 +638,17 @@ config IP_NF_TPROXY
To compile it as a module, choose M here. If unsure, say N.
+config IP_NF_TARGET_TPROXY
+ tristate "TPROXY target support"
+ depends on IP_NF_TPROXY
+ help
+ This option adds a `TPROXY' target, which is somewhat similar to
+ REDIRECT. It can only be used in the tproxy table and is useful
+ to redirect traffic to a transparent proxy. It does _not_ depend
+ on Netfilter connection tracking.
+
+ To compile it as a module, choose M here. If unsure, say N.
+
# ARP tables
config IP_NF_ARPTABLES
tristate "ARP tables support"
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index 21a29f4..a50a64e 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -106,6 +106,7 @@ obj-$(CONFIG_IP_NF_TARGET_LOG) += ipt_LOG.o
obj-$(CONFIG_IP_NF_TARGET_ULOG) += ipt_ULOG.o
obj-$(CONFIG_IP_NF_TARGET_CLUSTERIP) += ipt_CLUSTERIP.o
obj-$(CONFIG_IP_NF_TARGET_TTL) += ipt_TTL.o
+obj-$(CONFIG_IP_NF_TARGET_TPROXY) += ipt_TPROXY.o
# generic ARP tables
obj-$(CONFIG_IP_NF_ARPTABLES) += arp_tables.o
diff --git a/net/ipv4/netfilter/ipt_TPROXY.c b/net/ipv4/netfilter/ipt_TPROXY.c
new file mode 100644
index 0000000..89a08b1
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_TPROXY.c
@@ -0,0 +1,92 @@
+/*
+ * Transparent proxy support for Linux/iptables
+ *
+ * Copyright (c) 2006-2007 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.
+ *
+ */
+
+#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_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ip_tproxy.h>
+#include <linux/netfilter_ipv4/ipt_TPROXY.h>
+
+static unsigned int
+target(struct sk_buff **pskb,
+ const struct net_device *in,
+ const struct net_device *out,
+ unsigned int hooknum,
+ const struct xt_target *target,
+ const void *targinfo)
+{
+ const struct iphdr *iph = (*pskb)->nh.iph;
+ const struct ipt_tproxy_target_info *tgi =
+ (const struct ipt_tproxy_target_info *) targinfo;
+ unsigned int verdict = NF_ACCEPT;
+ struct sk_buff *skb = *pskb;
+ struct udphdr _hdr, *hp;
+ struct sock *sk;
+ __be32 daddr;
+ __be16 dport;
+
+ /* TCP/UDP only */
+ if ((iph->protocol != IPPROTO_TCP) &&
+ (iph->protocol != IPPROTO_UDP))
+ return NF_ACCEPT;
+
+ hp = skb_header_pointer(*pskb, iph->ihl * 4, sizeof(_hdr), &_hdr);
+ if (hp == NULL)
+ return NF_DROP;
+
+ daddr = tgi->laddr ? : iph->daddr;
+ dport = tgi->lport ? : hp->dest;
+ sk = ip_tproxy_get_sock(iph->protocol,
+ iph->saddr, daddr,
+ hp->source, dport, in);
+ if (sk != NULL) {
+ if (ip_tproxy_do_divert(skb, sk, 0, in) < 0)
+ verdict = NF_DROP;
+
+ if ((iph->protocol == IPPROTO_TCP) && (sk->sk_state == TCP_TIME_WAIT))
+ inet_twsk_put(inet_twsk(sk));
+ else
+ sock_put(sk);
+ }
+
+ return verdict;
+}
+
+static struct xt_target ipt_tproxy_reg = {
+ .name = "TPROXY",
+ .family = AF_INET,
+ .target = target,
+ .targetsize = sizeof(struct ipt_tproxy_target_info),
+ .table = "tproxy",
+ .me = THIS_MODULE,
+};
+
+static int __init init(void)
+{
+ return xt_register_target(&ipt_tproxy_reg);
+}
+
+static void __exit fini(void)
+{
+ xt_unregister_target(&ipt_tproxy_reg);
+}
+
+module_init(init);
+module_exit(fini);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Krisztian Kovacs <hidden@...abit.hu>");
+MODULE_DESCRIPTION("Netfilter transparent proxy TPROXY target module.");
-
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