[deliverable/linux.git] / net / ipv6 / netfilter / ip6t_mh.c

/*
 * 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 bool
type_match(u_int8_t min, u_int8_t max, u_int8_t type, bool invert)
{
	return (type >= min && type <= max) ^ invert;
}

static bool
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,
	 bool *hotdrop)
{
	struct ip6_mh _mh;
	const struct ip6_mh *mh;
	const struct ip6t_mh *mhinfo = matchinfo;

	/* Must not be a fragment. */
	if (offset)
		return false;

	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 = true;
		return false;
	}

	if (mh->ip6mh_proto != IPPROTO_NONE) {
		duprintf("Dropping invalid MH Payload Proto: %u\n",
			 mh->ip6mh_proto);
		*hotdrop = true;
		return false;
	}

	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 bool
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 __read_mostly = {
	.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);
Commit	Line	Data
a0ca215a MN	1	/*
	2	* Copyright (C)2006 USAGI/WIDE Project
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	* Author:
	9	* Masahide NAKAMURA @USAGI <masahide.nakamura.cz@hitachi.com>
	10	*
	11	* Based on net/netfilter/xt_tcpudp.c
	12	*
	13	*/
	14	#include <linux/types.h>
	15	#include <linux/module.h>
	16	#include <net/ip.h>
	17	#include <linux/ipv6.h>
	18	#include <net/ipv6.h>
	19	#include <net/mip6.h>
	20
	21	#include <linux/netfilter/x_tables.h>
	22	#include <linux/netfilter_ipv6/ip6t_mh.h>
	23
	24	MODULE_DESCRIPTION("ip6t_tables match for MH");
	25	MODULE_LICENSE("GPL");
	26
	27	#ifdef DEBUG_IP_FIREWALL_USER
	28	#define duprintf(format, args...) printk(format , ## args)
	29	#else
	30	#define duprintf(format, args...)
	31	#endif
	32
	33	/* Returns 1 if the type is matched by the range, 0 otherwise */
1d93a9cb JE	34	static inline bool
1d93a9cb JE	35	type_match(u_int8_t min, u_int8_t max, u_int8_t type, bool invert)
a0ca215a	36	{
1d93a9cb	37	return (type >= min && type <= max) ^ invert;
a0ca215a MN	38	}
a0ca215a MN	39
1d93a9cb	40	static bool
a0ca215a MN	41	match(const struct sk_buff *skb,
	42	const struct net_device *in,
	43	const struct net_device *out,
	44	const struct xt_match *match,
	45	const void *matchinfo,
	46	int offset,
	47	unsigned int protoff,
cff533ac	48	bool *hotdrop)
a0ca215a	49	{
a47362a2 JE	50	struct ip6_mh _mh;
a47362a2 JE	51	const struct ip6_mh *mh;
a0ca215a MN	52	const struct ip6t_mh *mhinfo = matchinfo;
	53
	54	/* Must not be a fragment. */
	55	if (offset)
1d93a9cb	56	return false;
a0ca215a MN	57
	58	mh = skb_header_pointer(skb, protoff, sizeof(_mh), &_mh);
	59	if (mh == NULL) {
	60	/* We've been asked to examine this packet, and we
	61	can't. Hence, no choice but to drop. */
	62	duprintf("Dropping evil MH tinygram.\n");
cff533ac	63	*hotdrop = true;
1d93a9cb	64	return false;
a0ca215a MN	65	}
a0ca215a MN	66
138939e0 MN	67	if (mh->ip6mh_proto != IPPROTO_NONE) {
	68	duprintf("Dropping invalid MH Payload Proto: %u\n",
	69	mh->ip6mh_proto);
cff533ac	70	*hotdrop = true;
1d93a9cb	71	return false;
138939e0 MN	72	}
138939e0 MN	73
a0ca215a MN	74	return type_match(mhinfo->types[0], mhinfo->types[1], mh->ip6mh_type,
	75	!!(mhinfo->invflags & IP6T_MH_INV_TYPE));
	76	}
	77
	78	/* Called when user tries to insert an entry of this type. */
ccb79bdc	79	static bool
a0ca215a MN	80	mh_checkentry(const char *tablename,
	81	const void *entry,
	82	const struct xt_match *match,
	83	void *matchinfo,
	84	unsigned int hook_mask)
	85	{
	86	const struct ip6t_mh *mhinfo = matchinfo;
	87
	88	/* Must specify no unknown invflags */
	89	return !(mhinfo->invflags & ~IP6T_MH_INV_MASK);
	90	}
	91
9f15c530	92	static struct xt_match mh_match __read_mostly = {
a0ca215a MN	93	.name = "mh",
	94	.family = AF_INET6,
	95	.checkentry = mh_checkentry,
	96	.match = match,
	97	.matchsize = sizeof(struct ip6t_mh),
	98	.proto = IPPROTO_MH,
	99	.me = THIS_MODULE,
	100	};
	101
	102	static int __init ip6t_mh_init(void)
	103	{
	104	return xt_register_match(&mh_match);
	105	}
	106
	107	static void __exit ip6t_mh_fini(void)
	108	{
	109	xt_unregister_match(&mh_match);
	110	}
	111
	112	module_init(ip6t_mh_init);
	113	module_exit(ip6t_mh_fini);