add netfilter TTL module

git-svn-id: svn://svn.openwrt.org/openwrt/trunk/openwrt@730 3c298f89-4303-0410-b956-a3cf2f4a3e73

2 files changed, 181 insertions, 0 deletions

diff --git a/package/linux/kernel-patches/312-netfilter-TTL b/package/linux/kernel-patches/312-netfilter-TTL
new file mode 100644
index 0000000000..f630f61e38
--- /dev/null
+++ b/package/linux/kernel-patches/312-netfilter-TTL
@@ -0,0 +1,180 @@
+diff -urN linux-2.4.30.old/Documentation/Configure.help linux-2.4.30.dev/Documentation/Configure.help
+--- linux-2.4.30.old/Documentation/Configure.help	2005-04-27 11:35:46.000000000 +0200
++++ linux-2.4.30.dev/Documentation/Configure.help	2005-04-27 11:43:49.000000000 +0200
+@@ -3209,6 +3209,15 @@
+   If you want to compile it as a module, say M here and read
+   <file:Documentation/modules.txt>.  If unsure, say `N'.
+ 
++TTL target support
++CONFIG_IP_NF_TARGET_TTL
++  This option adds a `TTL' target, which enables the user to set
++  the TTL value or increment / decrement the TTL value by a given
++  amount.
++
++  If you want to compile it as a module, say M here and read
++  Documentation/modules.txt.  If unsure, say `N'.
++
+ ipchains (2.2-style) support
+ CONFIG_IP_NF_COMPAT_IPCHAINS
+   This option places ipchains (with masquerading and redirection
+diff -urN linux-2.4.30.old/include/linux/netfilter_ipv4/ipt_TTL.h linux-2.4.30.dev/include/linux/netfilter_ipv4/ipt_TTL.h
+--- linux-2.4.30.old/include/linux/netfilter_ipv4/ipt_TTL.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-2.4.30.dev/include/linux/netfilter_ipv4/ipt_TTL.h	2005-04-27 11:43:49.000000000 +0200
+@@ -0,0 +1,21 @@
++/* TTL modification module for IP tables
++ * (C) 2000 by Harald Welte <laforge@gnumonks.org> */
++
++#ifndef _IPT_TTL_H
++#define _IPT_TTL_H
++
++enum {
++	IPT_TTL_SET = 0,
++	IPT_TTL_INC,
++	IPT_TTL_DEC
++};
++
++#define IPT_TTL_MAXMODE	IPT_TTL_DEC
++
++struct ipt_TTL_info {
++	u_int8_t	mode;
++	u_int8_t	ttl;
++};
++
++
++#endif
+diff -urN linux-2.4.30.old/net/ipv4/netfilter/Config.in linux-2.4.30.dev/net/ipv4/netfilter/Config.in
+--- linux-2.4.30.old/net/ipv4/netfilter/Config.in	2005-04-27 11:35:45.000000000 +0200
++++ linux-2.4.30.dev/net/ipv4/netfilter/Config.in	2005-04-27 11:43:49.000000000 +0200
+@@ -129,6 +129,7 @@
+     dep_tristate '    MARK target support' CONFIG_IP_NF_TARGET_MARK $CONFIG_IP_NF_MANGLE
+   fi
+   dep_tristate '  LOG target support' CONFIG_IP_NF_TARGET_LOG $CONFIG_IP_NF_IPTABLES
++  dep_tristate '  TTL target support' CONFIG_IP_NF_TARGET_TTL $CONFIG_IP_NF_IPTABLES
+   dep_tristate '  ULOG target support' CONFIG_IP_NF_TARGET_ULOG $CONFIG_IP_NF_IPTABLES
+   dep_tristate '  TCPMSS target support' CONFIG_IP_NF_TARGET_TCPMSS $CONFIG_IP_NF_IPTABLES
+ fi
+diff -urN linux-2.4.30.old/net/ipv4/netfilter/ipt_TTL.c linux-2.4.30.dev/net/ipv4/netfilter/ipt_TTL.c
+--- linux-2.4.30.old/net/ipv4/netfilter/ipt_TTL.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-2.4.30.dev/net/ipv4/netfilter/ipt_TTL.c	2005-04-27 11:43:49.000000000 +0200
+@@ -0,0 +1,110 @@
++/* TTL modification target for IP tables
++ * (C) 2000 by Harald Welte <laforge@gnumonks.org>
++ *
++ * Version: $Revision$
++ *
++ * This software is distributed under the terms of GNU GPL
++ */
++
++#include <linux/module.h>
++#include <linux/skbuff.h>
++#include <linux/ip.h>
++#include <net/checksum.h>
++
++#include <linux/netfilter_ipv4/ip_tables.h>
++#include <linux/netfilter_ipv4/ipt_TTL.h>
++
++MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
++MODULE_DESCRIPTION("IP tables TTL modification module");
++MODULE_LICENSE("GPL");
++
++static unsigned int ipt_ttl_target(struct sk_buff **pskb, unsigned int hooknum,
++		const struct net_device *in, const struct net_device *out,
++		const void *targinfo, void *userinfo)
++{
++	struct iphdr *iph = (*pskb)->nh.iph;
++	const struct ipt_TTL_info *info = targinfo;
++	u_int16_t diffs[2];
++	int new_ttl;
++			 
++	switch (info->mode) {
++		case IPT_TTL_SET:
++			new_ttl = info->ttl;
++			break;
++		case IPT_TTL_INC:
++			new_ttl = iph->ttl + info->ttl;
++			if (new_ttl > 255)
++				new_ttl = 255;
++			break;
++		case IPT_TTL_DEC:
++			new_ttl = iph->ttl - info->ttl;
++			if (new_ttl < 0)
++				new_ttl = 0;
++			break;
++		default:
++			new_ttl = iph->ttl;
++			break;
++	}
++
++	if (new_ttl != iph->ttl) {
++		diffs[0] = htons(((unsigned)iph->ttl) << 8) ^ 0xFFFF;
++		iph->ttl = new_ttl;
++		diffs[1] = htons(((unsigned)iph->ttl) << 8);
++		iph->check = csum_fold(csum_partial((char *)diffs,
++						    sizeof(diffs),
++				 	            iph->check^0xFFFF));
++									                	(*pskb)->nfcache |= NFC_ALTERED;
++	}
++
++	return IPT_CONTINUE;
++}
++
++static int ipt_ttl_checkentry(const char *tablename,
++		const struct ipt_entry *e,
++		void *targinfo,
++		unsigned int targinfosize,
++		unsigned int hook_mask)
++{
++	struct ipt_TTL_info *info = targinfo;
++
++	if (targinfosize != IPT_ALIGN(sizeof(struct ipt_TTL_info))) {
++		printk(KERN_WARNING "TTL: targinfosize %u != %Zu\n",
++				targinfosize,
++				IPT_ALIGN(sizeof(struct ipt_TTL_info)));
++		return 0;	
++	}	
++
++	if (strcmp(tablename, "mangle")) {
++		printk(KERN_WARNING "TTL: can only be called from \"mangle\" table, not \"%s\"\n", tablename);
++		return 0;
++	}
++
++	if (info->mode > IPT_TTL_MAXMODE) {
++		printk(KERN_WARNING "TTL: invalid or unknown Mode %u\n", 
++			info->mode);
++		return 0;
++	}
++
++	if ((info->mode != IPT_TTL_SET) && (info->ttl == 0)) {
++		printk(KERN_WARNING "TTL: increment/decrement doesn't make sense with value 0\n");
++		return 0;
++	}
++	
++	return 1;
++}
++
++static struct ipt_target ipt_TTL = { { NULL, NULL }, "TTL", 
++	ipt_ttl_target, ipt_ttl_checkentry, NULL, THIS_MODULE };
++
++static int __init init(void)
++{
++	return ipt_register_target(&ipt_TTL);
++}
++
++static void __exit fini(void)
++{
++	ipt_unregister_target(&ipt_TTL);
++}
++
++module_init(init);
++module_exit(fini);
+diff -urN linux-2.4.30.old/net/ipv4/netfilter/Makefile linux-2.4.30.dev/net/ipv4/netfilter/Makefile
+--- linux-2.4.30.old/net/ipv4/netfilter/Makefile	2005-04-27 11:35:45.000000000 +0200
++++ linux-2.4.30.dev/net/ipv4/netfilter/Makefile	2005-04-27 11:43:49.000000000 +0200
+@@ -112,6 +112,7 @@
+ obj-$(CONFIG_IP_NF_TARGET_REDIRECT) += ipt_REDIRECT.o
+ obj-$(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
+ obj-$(CONFIG_IP_NF_TARGET_ULOG) += ipt_ULOG.o
+ obj-$(CONFIG_IP_NF_TARGET_TCPMSS) += ipt_TCPMSS.o
+ 
diff --git a/package/linux/linux.config b/package/linux/linux.config
index abbafc19b7..d71a44df39 100644
--- a/package/linux/linux.config
+++ b/package/linux/linux.config
@@ -399,6 +399,7 @@ CONFIG_IP_NF_TARGET_ECN=m
 CONFIG_IP_NF_TARGET_DSCP=m
 CONFIG_IP_NF_TARGET_MARK=y
 CONFIG_IP_NF_TARGET_LOG=y
+CONFIG_IP_NF_TARGET_TTL=m
 CONFIG_IP_NF_TARGET_ULOG=m
 CONFIG_IP_NF_TARGET_TCPMSS=y
 CONFIG_IP_NF_ARPTABLES=m