patch-2.3.99-pre2 linux/net/ipv4/netfilter/ipt_REDIRECT.c

• Lines: 105
• Date: Fri Mar 17 10:56:20 2000
• Orig file: v2.3.99-pre1/linux/net/ipv4/netfilter/ipt_REDIRECT.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.99-pre1/linux/net/ipv4/netfilter/ipt_REDIRECT.c linux/net/ipv4/netfilter/ipt_REDIRECT.c
@@ -0,0 +1,104 @@
+/* Redirect.  Simple mapping which alters dst to a local IP address. */
+#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_ipv4/ip_nat_rule.h>
+
+EXPORT_NO_SYMBOLS;
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+/* FIXME: Take multiple ranges --RR */
+static int
+redirect_check(const char *tablename,
+	       const struct ipt_entry *e,
+	       void *targinfo,
+	       unsigned int targinfosize,
+	       unsigned int hook_mask)
+{
+	const struct ip_nat_multi_range *mr = targinfo;
+
+	if (targinfosize != IPT_ALIGN(sizeof(*mr))) {
+		DEBUGP("redirect_check: size %u.\n", targinfosize);
+		return 0;
+	}
+	if (hook_mask & ~((1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_LOCAL_OUT))) {
+		DEBUGP("redirect_check: bad hooks %x.\n", hook_mask);
+		return 0;
+	}
+	if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) {
+		DEBUGP("redirect_check: bad MAP_IPS.\n");
+		return 0;
+	}
+	if (mr->rangesize != 1) {
+		DEBUGP("redirect_check: bad rangesize %u.\n", mr->rangesize);
+		return 0;
+	}
+	return 1;
+}
+
+static unsigned int
+redirect_target(struct sk_buff **pskb,
+		unsigned int hooknum,
+		const struct net_device *in,
+		const struct net_device *out,
+		const void *targinfo,
+		void *userinfo)
+{
+	struct ip_conntrack *ct;
+	enum ip_conntrack_info ctinfo;
+	u_int32_t newdst;
+	const struct ip_nat_range *r = targinfo;
+	struct ip_nat_multi_range newrange;
+
+	IP_NF_ASSERT(hooknum == NF_IP_PRE_ROUTING
+		     || hooknum == NF_IP_LOCAL_OUT);
+
+	ct = ip_conntrack_get(*pskb, &ctinfo);
+	IP_NF_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
+
+	/* Local packets: make them go to loopback */
+	if (hooknum == NF_IP_LOCAL_OUT)
+		newdst = htonl(0x7F000001);
+	else
+		/* Grab first address on interface. */
+		newdst = (((struct in_device *)(*pskb)->dev->ip_ptr)
+			  ->ifa_list->ifa_local);
+
+	/* Transfer from original range. */
+	newrange = ((struct ip_nat_multi_range)
+		{ 1, { { r->flags | IP_NAT_RANGE_MAP_IPS,
+			 newdst, newdst,
+			 r->min, r->max } } });
+
+	/* Hand modified range to generic setup. */
+	return ip_nat_setup_info(ct, &newrange, hooknum);
+}
+
+static struct ipt_target redirect_reg
+= { { NULL, NULL }, "REDIRECT", redirect_target, redirect_check, THIS_MODULE };
+
+static int __init init(void)
+{
+	return ipt_register_target(&redirect_reg);
+}
+
+static void __exit fini(void)
+{
+	ipt_unregister_target(&redirect_reg);
+}
+
+module_init(init);
+module_exit(fini);