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/*
* Copyright (C)2006 USAGI/WIDE Project
*
* 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.
*
* Author:
* Masahide NAKAMURA @USAGI <masahide.nakamura.cz@hitachi.com>
*
* Based on net/netfilter/xt_tcpudp.c
*
*/
#include <linux/types.h>
#include <linux/module.h>
#include <net/ip.h>
#include <linux/ipv6.h>
#include <net/ipv6.h>
#include <net/mip6.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv6/ip6t_mh.h>
MODULE_DESCRIPTION("ip6t_tables match for MH");
MODULE_LICENSE("GPL");
#ifdef DEBUG_IP_FIREWALL_USER
#define duprintf(format, args...) printk(format , ## args)
#else
#define duprintf(format, args...)
#endif
/* Returns 1 if the type is matched by the range, 0 otherwise */
static inline int
type_match(u_int8_t min, u_int8_t max, u_int8_t type, int invert)
{
int ret;
ret = (type >= min && type <= max) ^ invert;
return ret;
}
static int
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const struct xt_match *match,
const void *matchinfo,
int offset,
unsigned int protoff,
int *hotdrop)
{
struct ip6_mh _mh, *mh;
const struct ip6t_mh *mhinfo = matchinfo;
/* Must not be a fragment. */
if (offset)
return 0;
mh = skb_header_pointer(skb, protoff, sizeof(_mh), &_mh);
if (mh == NULL) {
/* We've been asked to examine this packet, and we
can't. Hence, no choice but to drop. */
duprintf("Dropping evil MH tinygram.\n");
*hotdrop = 1;
return 0;
}
if (mh->ip6mh_proto != IPPROTO_NONE) {
duprintf("Dropping invalid MH Payload Proto: %u\n",
mh->ip6mh_proto);
*hotdrop = 1;
return 0;
}
return type_match(mhinfo->types[0], mhinfo->types[1], mh->ip6mh_type,
!!(mhinfo->invflags & IP6T_MH_INV_TYPE));
}
/* Called when user tries to insert an entry of this type. */
static int
mh_checkentry(const char *tablename,
const void *entry,
const struct xt_match *match,
void *matchinfo,
unsigned int hook_mask)
{
const struct ip6t_mh *mhinfo = matchinfo;
/* Must specify no unknown invflags */
return !(mhinfo->invflags & ~IP6T_MH_INV_MASK);
}
static struct xt_match mh_match = {
.name = "mh",
.family = AF_INET6,
.checkentry = mh_checkentry,
.match = match,
.matchsize = sizeof(struct ip6t_mh),
.proto = IPPROTO_MH,
.me = THIS_MODULE,
};
static int __init ip6t_mh_init(void)
{
return xt_register_match(&mh_match);
}
static void __exit ip6t_mh_fini(void)
{
xt_unregister_match(&mh_match);
}
module_init(ip6t_mh_init);
module_exit(ip6t_mh_fini);
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