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Message-Id: <1416835674-11871-2-git-send-email-pablo@netfilter.org>
Date: Mon, 24 Nov 2014 14:27:38 +0100
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 01/17] netfilter: refactor NAT redirect IPv4 to use it from nf_tables
From: Arturo Borrero <arturo.borrero.glez@...il.com>
This patch refactors the IPv4 code so it can be usable both from xt and
nf_tables.
A similar patch follows-up to handle IPv6.
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@...il.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
include/net/netfilter/ipv4/nf_nat_redirect.h | 9 +++
net/ipv4/netfilter/Kconfig | 6 ++
net/ipv4/netfilter/Makefile | 1 +
net/ipv4/netfilter/nf_nat_redirect_ipv4.c | 82 ++++++++++++++++++++++++++
net/netfilter/Kconfig | 1 +
net/netfilter/xt_REDIRECT.c | 44 +-------------
6 files changed, 101 insertions(+), 42 deletions(-)
create mode 100644 include/net/netfilter/ipv4/nf_nat_redirect.h
create mode 100644 net/ipv4/netfilter/nf_nat_redirect_ipv4.c
diff --git a/include/net/netfilter/ipv4/nf_nat_redirect.h b/include/net/netfilter/ipv4/nf_nat_redirect.h
new file mode 100644
index 0000000..19e1df3
--- /dev/null
+++ b/include/net/netfilter/ipv4/nf_nat_redirect.h
@@ -0,0 +1,9 @@
+#ifndef _NF_NAT_REDIRECT_IPV4_H_
+#define _NF_NAT_REDIRECT_IPV4_H_
+
+unsigned int
+nf_nat_redirect_ipv4(struct sk_buff *skb,
+ const struct nf_nat_ipv4_multi_range_compat *mr,
+ unsigned int hooknum);
+
+#endif /* _NF_NAT_REDIRECT_IPV4_H_ */
diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 4c019d5..a300e2c 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -104,6 +104,12 @@ config NF_NAT_MASQUERADE_IPV4
This is the kernel functionality to provide NAT in the masquerade
flavour (automatic source address selection).
+config NF_NAT_REDIRECT_IPV4
+ tristate "IPv4 redirect support"
+ help
+ This is the kernel functionality to provide NAT in the redirect
+ flavour (redirect packets to local machine).
+
config NFT_MASQ_IPV4
tristate "IPv4 masquerading support for nf_tables"
depends on NF_TABLES_IPV4
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index f4cef5a..34e436c 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -31,6 +31,7 @@ obj-$(CONFIG_NF_NAT_H323) += nf_nat_h323.o
obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o
obj-$(CONFIG_NF_NAT_SNMP_BASIC) += nf_nat_snmp_basic.o
obj-$(CONFIG_NF_NAT_MASQUERADE_IPV4) += nf_nat_masquerade_ipv4.o
+obj-$(CONFIG_NF_NAT_REDIRECT_IPV4) += nf_nat_redirect_ipv4.o
# NAT protocols (nf_nat)
obj-$(CONFIG_NF_NAT_PROTO_GRE) += nf_nat_proto_gre.o
diff --git a/net/ipv4/netfilter/nf_nat_redirect_ipv4.c b/net/ipv4/netfilter/nf_nat_redirect_ipv4.c
new file mode 100644
index 0000000..a220552
--- /dev/null
+++ b/net/ipv4/netfilter/nf_nat_redirect_ipv4.c
@@ -0,0 +1,82 @@
+/*
+ * (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@...filter.org>
+ * Copyright (c) 2011 Patrick McHardy <kaber@...sh.net>
+ *
+ * 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.
+ *
+ * Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6
+ * NAT funded by Astaro.
+ */
+
+#include <linux/if.h>
+#include <linux/inetdevice.h>
+#include <linux/ip.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/netfilter.h>
+#include <linux/types.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter/x_tables.h>
+#include <net/addrconf.h>
+#include <net/checksum.h>
+#include <net/protocol.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/ipv4/nf_nat_redirect.h>
+
+unsigned int
+nf_nat_redirect_ipv4(struct sk_buff *skb,
+ const struct nf_nat_ipv4_multi_range_compat *mr,
+ unsigned int hooknum)
+{
+ struct nf_conn *ct;
+ enum ip_conntrack_info ctinfo;
+ __be32 newdst;
+ struct nf_nat_range newrange;
+
+ NF_CT_ASSERT(hooknum == NF_INET_PRE_ROUTING ||
+ hooknum == NF_INET_LOCAL_OUT);
+
+ ct = nf_ct_get(skb, &ctinfo);
+ NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
+
+ /* Local packets: make them go to loopback */
+ if (hooknum == NF_INET_LOCAL_OUT) {
+ newdst = htonl(0x7F000001);
+ } else {
+ struct in_device *indev;
+ struct in_ifaddr *ifa;
+
+ newdst = 0;
+
+ rcu_read_lock();
+ indev = __in_dev_get_rcu(skb->dev);
+ if (indev != NULL) {
+ ifa = indev->ifa_list;
+ newdst = ifa->ifa_local;
+ }
+ rcu_read_unlock();
+
+ if (!newdst)
+ return NF_DROP;
+ }
+
+ /* Transfer from original range. */
+ memset(&newrange.min_addr, 0, sizeof(newrange.min_addr));
+ memset(&newrange.max_addr, 0, sizeof(newrange.max_addr));
+ newrange.flags = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS;
+ newrange.min_addr.ip = newdst;
+ newrange.max_addr.ip = newdst;
+ newrange.min_proto = mr->range[0].min;
+ newrange.max_proto = mr->range[0].max;
+
+ /* Hand modified range to generic setup. */
+ return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
+}
+EXPORT_SYMBOL_GPL(nf_nat_redirect_ipv4);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <kaber@...sh.net>");
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index ae5096a..a0716a3 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -835,6 +835,7 @@ config NETFILTER_XT_TARGET_RATEEST
config NETFILTER_XT_TARGET_REDIRECT
tristate "REDIRECT target support"
depends on NF_NAT
+ select NF_NAT_REDIRECT_IPV4
---help---
REDIRECT is a special case of NAT: all incoming connections are
mapped onto the incoming interface's address, causing the packets to
diff --git a/net/netfilter/xt_REDIRECT.c b/net/netfilter/xt_REDIRECT.c
index 22a1030..b4ffac5 100644
--- a/net/netfilter/xt_REDIRECT.c
+++ b/net/netfilter/xt_REDIRECT.c
@@ -26,6 +26,7 @@
#include <net/checksum.h>
#include <net/protocol.h>
#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/ipv4/nf_nat_redirect.h>
static const struct in6_addr loopback_addr = IN6ADDR_LOOPBACK_INIT;
@@ -98,48 +99,7 @@ static int redirect_tg4_check(const struct xt_tgchk_param *par)
static unsigned int
redirect_tg4(struct sk_buff *skb, const struct xt_action_param *par)
{
- struct nf_conn *ct;
- enum ip_conntrack_info ctinfo;
- __be32 newdst;
- const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
- struct nf_nat_range newrange;
-
- NF_CT_ASSERT(par->hooknum == NF_INET_PRE_ROUTING ||
- par->hooknum == NF_INET_LOCAL_OUT);
-
- ct = nf_ct_get(skb, &ctinfo);
- NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
-
- /* Local packets: make them go to loopback */
- if (par->hooknum == NF_INET_LOCAL_OUT)
- newdst = htonl(0x7F000001);
- else {
- struct in_device *indev;
- struct in_ifaddr *ifa;
-
- newdst = 0;
-
- rcu_read_lock();
- indev = __in_dev_get_rcu(skb->dev);
- if (indev && (ifa = indev->ifa_list))
- newdst = ifa->ifa_local;
- rcu_read_unlock();
-
- if (!newdst)
- return NF_DROP;
- }
-
- /* Transfer from original range. */
- memset(&newrange.min_addr, 0, sizeof(newrange.min_addr));
- memset(&newrange.max_addr, 0, sizeof(newrange.max_addr));
- newrange.flags = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS;
- newrange.min_addr.ip = newdst;
- newrange.max_addr.ip = newdst;
- newrange.min_proto = mr->range[0].min;
- newrange.max_proto = mr->range[0].max;
-
- /* Hand modified range to generic setup. */
- return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
+ return nf_nat_redirect_ipv4(skb, par->targinfo, par->hooknum);
}
static struct xt_target redirect_tg_reg[] __read_mostly = {
--
1.7.10.4
--
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