diff -Naur linux-2.6.3-orig/include/linux/netfilter_ipv4/ipt_TTL.h linux-2.6.3/include/linux/netfilter_ipv4/ipt_TTL.h --- linux-2.6.3-orig/include/linux/netfilter_ipv4/ipt_TTL.h 1970-01-01 01:00:00.000000000 +0100 +++ linux-2.6.3/include/linux/netfilter_ipv4/ipt_TTL.h 2004-02-18 22:20:01.000000000 +0100 @@ -0,0 +1,21 @@ +/* TTL modification module for IP tables + * (C) 2000 by Harald Welte */ + +#ifndef _IPT_TTL_H +#define _IPT_TTL_H + +enum ipt_TTL_mode { + 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 -Naur linux-2.6.3-orig/net/ipv4/netfilter/ipt_TTL.c linux-2.6.3/net/ipv4/netfilter/ipt_TTL.c --- linux-2.6.3-orig/net/ipv4/netfilter/ipt_TTL.c 1970-01-01 01:00:00.000000000 +0100 +++ linux-2.6.3/net/ipv4/netfilter/ipt_TTL.c 2004-02-18 22:10:35.000000000 +0100 @@ -0,0 +1,119 @@ +/* TTL modification target for IP tables + * (C) 2000 by Harald Welte + * + * Version: 1.8 + * + * This software is distributed under the terms of GNU GPL + */ + +#include +#include +#include +#include + +#include +#include + +MODULE_AUTHOR("Harald Welte "); +MODULE_DESCRIPTION("IP tables TTL modification module"); +MODULE_LICENSE("GPL"); + +static unsigned int +target(struct sk_buff **pskb, + const struct net_device *in, + const struct net_device *out, + unsigned int hooknum, + 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 +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_reg = { + .name = "TTL", + .target = target, + .checkentry = checkentry, + .me = THIS_MODULE, +}; + +static int __init init(void) +{ + return ipt_register_target(&ipt_ttl_reg); +} + +static void __exit fini(void) +{ + ipt_unregister_target(&ipt_ttl_reg); +} + +module_init(init); +module_exit(fini); diff -Naur linux-2.6.3-orig/net/ipv4/netfilter/Kconfig linux-2.6.3/net/ipv4/netfilter/Kconfig --- linux-2.6.3-orig/net/ipv4/netfilter/Kconfig 2004-02-18 17:21:29.000000000 +0100 +++ linux-2.6.3/net/ipv4/netfilter/Kconfig 2004-02-18 23:06:53.000000000 +0100 @@ -487,6 +487,16 @@ To compile it as a module, choose M here. If unsure, say N. +config IP_NF_TARGET_TTL + tristate "TTL target support" + depends on IP_NF_IPTABLES + help + 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. + + To compile it as a module, choose M here. If unsure, say N. + config IP_NF_TARGET_ULOG tristate "ULOG target support" depends on IP_NF_IPTABLES diff -Naur linux-2.6.3-orig/net/ipv4/netfilter/Makefile linux-2.6.3/net/ipv4/netfilter/Makefile --- linux-2.6.3-orig/net/ipv4/netfilter/Makefile 2004-02-18 17:21:29.000000000 +0100 +++ linux-2.6.3/net/ipv4/netfilter/Makefile 2004-02-18 23:06:53.000000000 +0100 @@ -81,6 +81,7 @@ obj-$(CONFIG_IP_NF_TARGET_LOG) += ipt_LOG.o obj-$(CONFIG_IP_NF_TARGET_ULOG) += ipt_ULOG.o obj-$(CONFIG_IP_NF_TARGET_TCPMSS) += ipt_TCPMSS.o +obj-$(CONFIG_IP_NF_TARGET_TTL) += ipt_TTL.o # generic ARP tables obj-$(CONFIG_IP_NF_ARPTABLES) += arp_tables.o @@ -94,3 +95,4 @@ obj-$(CONFIG_IP_NF_COMPAT_IPFWADM) += ipfwadm.o obj-$(CONFIG_IP_NF_QUEUE) += ip_queue.o +