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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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17
net/ipv6/netfilter/Kconfig
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@@ -170,23 +170,6 @@ config IP6_NF_MANGLE
To compile it as a module, choose M here. If unsure, say N.
config IP6_NF_TARGET_HL
tristate 'HL (hoplimit) target support'
depends on IP6_NF_MANGLE
depends on NETFILTER_ADVANCED
help
This option adds a `HL' target, which enables the user to decrement
the hoplimit value of the IPv6 header or set it to a given (lower)
value.
While it is safe to decrement the hoplimit value, this option also
enables functionality to increment and set the hoplimit value of the
IPv6 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.
config IP6_NF_RAW
tristate 'raw table support (required for TRACE)'
depends on NETFILTER_ADVANCED

1
net/ipv6/netfilter/Makefile
View File

@@ -27,6 +27,5 @@ obj-$(CONFIG_IP6_NF_MATCH_OPTS) += ip6t_hbh.o
obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o
# targets
obj-$(CONFIG_IP6_NF_TARGET_HL) += ip6t_HL.o
obj-$(CONFIG_IP6_NF_TARGET_LOG) += ip6t_LOG.o
obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o

95
net/ipv6/netfilter/ip6t_HL.c
View File

@@ -1,95 +0,0 @@
/*
* Hop Limit modification target for ip6tables
* Maciej Soltysiak <solt@dns.toxicfilms.tv>
* Based on HW's TTL module
*
* This software is distributed under the terms of GNU GPL
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv6/ip6t_HL.h>
MODULE_AUTHOR("Maciej Soltysiak <solt@dns.toxicfilms.tv>");
MODULE_DESCRIPTION("Xtables: IPv6 Hop Limit field modification target");
MODULE_LICENSE("GPL");
static unsigned int
hl_tg6(struct sk_buff *skb, const struct xt_target_param *par)
{
struct ipv6hdr *ip6h;
const struct ip6t_HL_info *info = par->targinfo;
int new_hl;
if (!skb_make_writable(skb, skb->len))
return NF_DROP;
ip6h = ipv6_hdr(skb);
switch (info->mode) {
case IP6T_HL_SET:
new_hl = info->hop_limit;
break;
case IP6T_HL_INC:
new_hl = ip6h->hop_limit + info->hop_limit;
if (new_hl > 255)
new_hl = 255;
break;
case IP6T_HL_DEC:
new_hl = ip6h->hop_limit - info->hop_limit;
if (new_hl < 0)
new_hl = 0;
break;
default:
new_hl = ip6h->hop_limit;
break;
}
ip6h->hop_limit = new_hl;
return XT_CONTINUE;
}
static bool hl_tg6_check(const struct xt_tgchk_param *par)
{
const struct ip6t_HL_info *info = par->targinfo;
if (info->mode > IP6T_HL_MAXMODE) {
printk(KERN_WARNING "ip6t_HL: invalid or unknown Mode %u\n",
info->mode);
return false;
}
if (info->mode != IP6T_HL_SET && info->hop_limit == 0) {
printk(KERN_WARNING "ip6t_HL: increment/decrement doesn't "
"make sense with value 0\n");
return false;
}
return true;
}
static struct xt_target hl_tg6_reg __read_mostly = {
.name = "HL",
.family = NFPROTO_IPV6,
.target = hl_tg6,
.targetsize = sizeof(struct ip6t_HL_info),
.table = "mangle",
.checkentry = hl_tg6_check,
.me = THIS_MODULE
};
static int __init hl_tg6_init(void)
{
return xt_register_target(&hl_tg6_reg);
}
static void __exit hl_tg6_exit(void)
{
xt_unregister_target(&hl_tg6_reg);
}
module_init(hl_tg6_init);
module_exit(hl_tg6_exit);