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netfilter: Combine ipt_TTL and ip6t_HL source

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Suggested by: James King <t.james.king@gmail.com>

Similarly to commit c9fd496809, merge
TTL and HL. Since HL does not depend on any IPv6-specific function,
no new module dependencies would arise.

With slight adjustments to the Kconfig help text.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Jan Engelhardt
2009-02-18 18:38:40 +01:00
committed by Patrick McHardy
parent ddc214c43a
commit 563d36eb3f
9 changed files with 187 additions and 226 deletions
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15
net/ipv4/netfilter/Kconfig
View File

@@ -322,21 +322,6 @@ config IP_NF_TARGET_ECN
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_MANGLE
depends on NETFILTER_ADVANCED
help
This option adds a `TTL' target, which enables the user to modify
the TTL value of the IP header.
While it is safe to decrement/lower the TTL, this target also enables
functionality to increment and set the TTL value of the IP header to
arbitrary values. This is EXTREMELY DANGEROUS since you can easily
create immortal packets that loop forever on the network.
To compile it as a module, choose M here. If unsure, say N.
# raw + specific targets
config IP_NF_RAW
tristate 'raw table support (required for NOTRACK/TRACE)'

1
net/ipv4/netfilter/Makefile
View File

@@ -61,7 +61,6 @@ obj-$(CONFIG_IP_NF_TARGET_MASQUERADE) += ipt_MASQUERADE.o
obj-$(CONFIG_IP_NF_TARGET_NETMAP) += ipt_NETMAP.o
obj-$(CONFIG_IP_NF_TARGET_REDIRECT) += ipt_REDIRECT.o
obj-$(CONFIG_IP_NF_TARGET_REJECT) += ipt_REJECT.o
obj-$(CONFIG_IP_NF_TARGET_TTL) += ipt_TTL.o
obj-$(CONFIG_IP_NF_TARGET_ULOG) += ipt_ULOG.o
# generic ARP tables

97
net/ipv4/netfilter/ipt_TTL.c
View File

@@ -1,97 +0,0 @@
/* TTL modification target for IP tables
* (C) 2000,2005 by Harald Welte <laforge@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/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <net/checksum.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ipt_TTL.h>
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_DESCRIPTION("Xtables: IPv4 TTL field modification target");
MODULE_LICENSE("GPL");
static unsigned int
ttl_tg(struct sk_buff *skb, const struct xt_target_param *par)
{
struct iphdr *iph;
const struct ipt_TTL_info *info = par->targinfo;
int new_ttl;
if (!skb_make_writable(skb, skb->len))
return NF_DROP;
iph = ip_hdr(skb);
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) {
csum_replace2(&iph->check, htons(iph->ttl << 8),
htons(new_ttl << 8));
iph->ttl = new_ttl;
}
return XT_CONTINUE;
}
static bool ttl_tg_check(const struct xt_tgchk_param *par)
{
const struct ipt_TTL_info *info = par->targinfo;
if (info->mode > IPT_TTL_MAXMODE) {
printk(KERN_WARNING "ipt_TTL: invalid or unknown Mode %u\n",
info->mode);
return false;
}
if (info->mode != IPT_TTL_SET && info->ttl == 0)
return false;
return true;
}
static struct xt_target ttl_tg_reg __read_mostly = {
.name = "TTL",
.family = NFPROTO_IPV4,
.target = ttl_tg,
.targetsize = sizeof(struct ipt_TTL_info),
.table = "mangle",
.checkentry = ttl_tg_check,
.me = THIS_MODULE,
};
static int __init ttl_tg_init(void)
{
return xt_register_target(&ttl_tg_reg);
}
static void __exit ttl_tg_exit(void)
{
xt_unregister_target(&ttl_tg_reg);
}
module_init(ttl_tg_init);
module_exit(ttl_tg_exit);