1 files changed, 110 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_REDIRECT.c b/net/ipv4/netfilter/ipt_REDIRECT.c
new file mode 100644
index 0000000..698e5e7
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_REDIRECT.c
@@ -0,0 +1,110 @@
+/* Redirect.  Simple mapping which alters dst to a local IP address. */
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ *
+ * 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/types.h>
+#include <linux/ip.h>
+#include <linux/timer.h>
+#include <linux/module.h>
+#include <linux/netfilter.h>
+#include <linux/netdevice.h>
+#include <linux/if.h>
+#include <linux/inetdevice.h>
+#include <net/protocol.h>
+#include <net/checksum.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter/x_tables.h>
+#include <net/netfilter/nf_nat_rule.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
+MODULE_DESCRIPTION("Xtables: Connection redirection to localhost");
+
+/* FIXME: Take multiple ranges --RR */
+static bool redirect_tg_check(const struct xt_tgchk_param *par)
+{
+	const struct nf_nat_multi_range_compat *mr = par->targinfo;
+
+	if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) {
+		pr_debug("redirect_check: bad MAP_IPS.\n");
+		return false;
+	}
+	if (mr->rangesize != 1) {
+		pr_debug("redirect_check: bad rangesize %u.\n", mr->rangesize);
+		return false;
+	}
+	return true;
+}
+
+static unsigned int
+redirect_tg(struct sk_buff *skb, const struct xt_target_param *par)
+{
+	struct nf_conn *ct;
+	enum ip_conntrack_info ctinfo;
+	__be32 newdst;
+	const struct nf_nat_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. */
+	newrange = ((struct nf_nat_range)
+		{ mr->range[0].flags | IP_NAT_RANGE_MAP_IPS,
+		  newdst, newdst,
+		  mr->range[0].min, mr->range[0].max });
+
+	/* Hand modified range to generic setup. */
+	return nf_nat_setup_info(ct, &newrange, IP_NAT_MANIP_DST);
+}
+
+static struct xt_target redirect_tg_reg __read_mostly = {
+	.name		= "REDIRECT",
+	.family		= NFPROTO_IPV4,
+	.target		= redirect_tg,
+	.targetsize	= sizeof(struct nf_nat_multi_range_compat),
+	.table		= "nat",
+	.hooks		= (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT),
+	.checkentry	= redirect_tg_check,
+	.me		= THIS_MODULE,
+};
+
+static int __init redirect_tg_init(void)
+{
+	return xt_register_target(&redirect_tg_reg);
+}
+
+static void __exit redirect_tg_exit(void)
+{
+	xt_unregister_target(&redirect_tg_reg);
+}
+
+module_init(redirect_tg_init);
+module_exit(redirect_tg_exit);