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diff -urN linux-2.4.30.orig/Documentation/Configure.help linux-2.4.30/Documentation/Configure.help
--- linux-2.4.30.orig/Documentation/Configure.help 2005-07-01 02:06:36.000000000 +0200
+++ linux-2.4.30/Documentation/Configure.help 2005-07-01 00:41:09.000000000 +0200
@@ -3086,6 +3086,17 @@
If you want to compile it as a module, say M here and read
<file:Documentation/modules.txt>. If unsure, say `N'.
+NETMAP target support
+CONFIG_IP_NF_TARGET_NETMAP
+ NETMAP is an implementation of static 1:1 NAT mapping of network
+ addresses. It maps the network address part, while keeping the
+ host address part intact. It is similar to Fast NAT, except that
+ Netfilter's connection tracking doesn't work well with Fast NAT.
+
+ If you want to compile it as a module, say M here and read
+ Documentation/modules.txt. The module will be called
+ ipt_NETMAP.o. If unsure, say `N'.
+
Packet mangling
CONFIG_IP_NF_MANGLE
This option adds a `mangle' table to iptables: see the man page for
diff -urN linux-2.4.30.orig/net/ipv4/netfilter/Config.in linux-2.4.30/net/ipv4/netfilter/Config.in
--- linux-2.4.30.orig/net/ipv4/netfilter/Config.in 2005-07-01 02:06:35.000000000 +0200
+++ linux-2.4.30/net/ipv4/netfilter/Config.in 2005-07-01 00:41:09.000000000 +0200
@@ -69,6 +69,7 @@
define_bool CONFIG_IP_NF_NAT_NEEDED y
dep_tristate ' MASQUERADE target support' CONFIG_IP_NF_TARGET_MASQUERADE $CONFIG_IP_NF_NAT
dep_tristate ' REDIRECT target support' CONFIG_IP_NF_TARGET_REDIRECT $CONFIG_IP_NF_NAT
+ dep_tristate ' NETMAP target support' CONFIG_IP_NF_TARGET_NETMAP $CONFIG_IP_NF_NAT
if [ "$CONFIG_IP_NF_PPTP" = "m" ]; then
define_tristate CONFIG_IP_NF_NAT_PPTP m
else
diff -urN linux-2.4.30.orig/net/ipv4/netfilter/ipt_NETMAP.c linux-2.4.30/net/ipv4/netfilter/ipt_NETMAP.c
--- linux-2.4.30.orig/net/ipv4/netfilter/ipt_NETMAP.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.4.30/net/ipv4/netfilter/ipt_NETMAP.c 2005-07-01 00:41:09.000000000 +0200
@@ -0,0 +1,112 @@
+/* NETMAP - static NAT mapping of IP network addresses (1:1).
+ The mapping can be applied to source (POSTROUTING),
+ destination (PREROUTING), or both (with separate rules).
+
+ Author: Svenning Soerensen <svenning@post5.tele.dk>
+*/
+
+#include <linux/config.h>
+#include <linux/ip.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter_ipv4/ip_nat_rule.h>
+
+#define MODULENAME "NETMAP"
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Svenning Soerensen <svenning@post5.tele.dk>");
+MODULE_DESCRIPTION("iptables 1:1 NAT mapping of IP networks target");
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+static int
+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 (strcmp(tablename, "nat") != 0) {
+ DEBUGP(MODULENAME":check: bad table `%s'.\n", tablename);
+ return 0;
+ }
+ if (targinfosize != IPT_ALIGN(sizeof(*mr))) {
+ DEBUGP(MODULENAME":check: size %u.\n", targinfosize);
+ return 0;
+ }
+ if (hook_mask & ~((1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_POST_ROUTING))) {
+ DEBUGP(MODULENAME":check: bad hooks %x.\n", hook_mask);
+ return 0;
+ }
+ if (!(mr->range[0].flags & IP_NAT_RANGE_MAP_IPS)) {
+ DEBUGP(MODULENAME":check: bad MAP_IPS.\n");
+ return 0;
+ }
+ if (mr->rangesize != 1) {
+ DEBUGP(MODULENAME":check: bad rangesize %u.\n", mr->rangesize);
+ return 0;
+ }
+ return 1;
+}
+
+static unsigned int
+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 new_ip, netmask;
+ const struct ip_nat_multi_range *mr = targinfo;
+ struct ip_nat_multi_range newrange;
+
+ IP_NF_ASSERT(hooknum == NF_IP_PRE_ROUTING
+ || hooknum == NF_IP_POST_ROUTING);
+ ct = ip_conntrack_get(*pskb, &ctinfo);
+
+ netmask = ~(mr->range[0].min_ip ^ mr->range[0].max_ip);
+
+ if (hooknum == NF_IP_PRE_ROUTING)
+ new_ip = (*pskb)->nh.iph->daddr & ~netmask;
+ else
+ new_ip = (*pskb)->nh.iph->saddr & ~netmask;
+ new_ip |= mr->range[0].min_ip & netmask;
+
+ newrange = ((struct ip_nat_multi_range)
+ { 1, { { mr->range[0].flags | IP_NAT_RANGE_MAP_IPS,
+ new_ip, new_ip,
+ mr->range[0].min, mr->range[0].max } } });
+
+ /* Hand modified range to generic setup. */
+ return ip_nat_setup_info(ct, &newrange, hooknum);
+}
+
+static struct ipt_target target_module = {
+ .name = MODULENAME,
+ .target = target,
+ .checkentry = check,
+ .me = THIS_MODULE
+};
+
+static int __init init(void)
+{
+ return ipt_register_target(&target_module);
+}
+
+static void __exit fini(void)
+{
+ ipt_unregister_target(&target_module);
+}
+
+module_init(init);
+module_exit(fini);
diff -urN linux-2.4.30.orig/net/ipv4/netfilter/Makefile linux-2.4.30/net/ipv4/netfilter/Makefile
--- linux-2.4.30.orig/net/ipv4/netfilter/Makefile 2005-07-01 02:06:35.000000000 +0200
+++ linux-2.4.30/net/ipv4/netfilter/Makefile 2005-07-01 00:41:09.000000000 +0200
@@ -110,6 +110,7 @@
obj-$(CONFIG_IP_NF_TARGET_MARK) += ipt_MARK.o
obj-$(CONFIG_IP_NF_TARGET_MASQUERADE) += ipt_MASQUERADE.o
obj-$(CONFIG_IP_NF_TARGET_REDIRECT) += ipt_REDIRECT.o
+obj-$(CONFIG_IP_NF_TARGET_NETMAP) += ipt_NETMAP.o
obj-$(CONFIG_IP_NF_NAT_SNMP_BASIC) += ip_nat_snmp_basic.o
obj-$(CONFIG_IP_NF_TARGET_LOG) += ipt_LOG.o
obj-$(CONFIG_IP_NF_TARGET_TTL) += ipt_TTL.o
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