[net-next-2.6.git] / net / bridge / netfilter / ebt_stp.c

/*
 *  ebt_stp
 *
 *	Authors:
 *	Bart De Schuymer <bdschuym@pandora.be>
 *	Stephen Hemminger <shemminger@osdl.org>
 *
 *  July, 2003
 */
#include <linux/etherdevice.h>
#include <linux/module.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_stp.h>

#define BPDU_TYPE_CONFIG 0
#define BPDU_TYPE_TCN 0x80

struct stp_header {
	uint8_t dsap;
	uint8_t ssap;
	uint8_t ctrl;
	uint8_t pid;
	uint8_t vers;
	uint8_t type;
};

struct stp_config_pdu {
	uint8_t flags;
	uint8_t root[8];
	uint8_t root_cost[4];
	uint8_t sender[8];
	uint8_t port[2];
	uint8_t msg_age[2];
	uint8_t max_age[2];
	uint8_t hello_time[2];
	uint8_t forward_delay[2];
};

#define NR16(p) (p[0] << 8 | p[1])
#define NR32(p) ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3])

static bool ebt_filter_config(const struct ebt_stp_info *info,
   const struct stp_config_pdu *stpc)
{
	const struct ebt_stp_config_info *c;
	uint16_t v16;
	uint32_t v32;
	int verdict, i;

	c = &info->config;
	if ((info->bitmask & EBT_STP_FLAGS) &&
	    FWINV(c->flags != stpc->flags, EBT_STP_FLAGS))
		return false;
	if (info->bitmask & EBT_STP_ROOTPRIO) {
		v16 = NR16(stpc->root);
		if (FWINV(v16 < c->root_priol ||
		    v16 > c->root_priou, EBT_STP_ROOTPRIO))
			return false;
	}
	if (info->bitmask & EBT_STP_ROOTADDR) {
		verdict = 0;
		for (i = 0; i < 6; i++)
			verdict |= (stpc->root[2+i] ^ c->root_addr[i]) &
				   c->root_addrmsk[i];
		if (FWINV(verdict != 0, EBT_STP_ROOTADDR))
			return false;
	}
	if (info->bitmask & EBT_STP_ROOTCOST) {
		v32 = NR32(stpc->root_cost);
		if (FWINV(v32 < c->root_costl ||
		    v32 > c->root_costu, EBT_STP_ROOTCOST))
			return false;
	}
	if (info->bitmask & EBT_STP_SENDERPRIO) {
		v16 = NR16(stpc->sender);
		if (FWINV(v16 < c->sender_priol ||
		    v16 > c->sender_priou, EBT_STP_SENDERPRIO))
			return false;
	}
	if (info->bitmask & EBT_STP_SENDERADDR) {
		verdict = 0;
		for (i = 0; i < 6; i++)
			verdict |= (stpc->sender[2+i] ^ c->sender_addr[i]) &
				   c->sender_addrmsk[i];
		if (FWINV(verdict != 0, EBT_STP_SENDERADDR))
			return false;
	}
	if (info->bitmask & EBT_STP_PORT) {
		v16 = NR16(stpc->port);
		if (FWINV(v16 < c->portl ||
		    v16 > c->portu, EBT_STP_PORT))
			return false;
	}
	if (info->bitmask & EBT_STP_MSGAGE) {
		v16 = NR16(stpc->msg_age);
		if (FWINV(v16 < c->msg_agel ||
		    v16 > c->msg_ageu, EBT_STP_MSGAGE))
			return false;
	}
	if (info->bitmask & EBT_STP_MAXAGE) {
		v16 = NR16(stpc->max_age);
		if (FWINV(v16 < c->max_agel ||
		    v16 > c->max_ageu, EBT_STP_MAXAGE))
			return false;
	}
	if (info->bitmask & EBT_STP_HELLOTIME) {
		v16 = NR16(stpc->hello_time);
		if (FWINV(v16 < c->hello_timel ||
		    v16 > c->hello_timeu, EBT_STP_HELLOTIME))
			return false;
	}
	if (info->bitmask & EBT_STP_FWDD) {
		v16 = NR16(stpc->forward_delay);
		if (FWINV(v16 < c->forward_delayl ||
		    v16 > c->forward_delayu, EBT_STP_FWDD))
			return false;
	}
	return true;
}

static bool ebt_filter_stp(const struct sk_buff *skb,
   const struct net_device *in,
   const struct net_device *out, const void *data, unsigned int datalen)
{
	const struct ebt_stp_info *info = data;
	const struct stp_header *sp;
	struct stp_header _stph;
	const uint8_t header[6] = {0x42, 0x42, 0x03, 0x00, 0x00, 0x00};

	sp = skb_header_pointer(skb, 0, sizeof(_stph), &_stph);
	if (sp == NULL)
		return false;

	/* The stp code only considers these */
	if (memcmp(sp, header, sizeof(header)))
		return false;

	if (info->bitmask & EBT_STP_TYPE
	    && FWINV(info->type != sp->type, EBT_STP_TYPE))
		return false;

	if (sp->type == BPDU_TYPE_CONFIG &&
	    info->bitmask & EBT_STP_CONFIG_MASK) {
		const struct stp_config_pdu *st;
		struct stp_config_pdu _stpc;

		st = skb_header_pointer(skb, sizeof(_stph),
					sizeof(_stpc), &_stpc);
		if (st == NULL)
			return false;
		return ebt_filter_config(info, st);
	}
	return true;
}

static bool ebt_stp_check(const char *tablename, unsigned int hookmask,
   const struct ebt_entry *e, void *data, unsigned int datalen)
{
	const struct ebt_stp_info *info = data;
	const uint8_t bridge_ula[6] = {0x01, 0x80, 0xc2, 0x00, 0x00, 0x00};
	const uint8_t msk[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

	if (info->bitmask & ~EBT_STP_MASK || info->invflags & ~EBT_STP_MASK ||
	    !(info->bitmask & EBT_STP_MASK))
		return false;
	/* Make sure the match only receives stp frames */
	if (compare_ether_addr(e->destmac, bridge_ula) ||
	    compare_ether_addr(e->destmsk, msk) || !(e->bitmask & EBT_DESTMAC))
		return false;

	return true;
}

static struct ebt_match filter_stp __read_mostly = {
	.name		= EBT_STP_MATCH,
	.revision	= 0,
	.family		= NFPROTO_BRIDGE,
	.match		= ebt_filter_stp,
	.check		= ebt_stp_check,
	.matchsize	= XT_ALIGN(sizeof(struct ebt_stp_info)),
	.me		= THIS_MODULE,
};

static int __init ebt_stp_init(void)
{
	return ebt_register_match(&filter_stp);
}

static void __exit ebt_stp_fini(void)
{
	ebt_unregister_match(&filter_stp);
}

module_init(ebt_stp_init);
module_exit(ebt_stp_fini);
MODULE_DESCRIPTION("Ebtables: Spanning Tree Protocol packet match");
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* ebt_stp
	3	*
	4	* Authors:
	5	* Bart De Schuymer <bdschuym@pandora.be>
	6	* Stephen Hemminger <shemminger@osdl.org>
	7	*
	8	* July, 2003
	9	*/
82bf7e97	10	#include <linux/etherdevice.h>
1da177e4	11	#include <linux/module.h>
18219d3f JE	12	#include <linux/netfilter/x_tables.h>
	13	#include <linux/netfilter_bridge/ebtables.h>
	14	#include <linux/netfilter_bridge/ebt_stp.h>
1da177e4 LT	15
	16	#define BPDU_TYPE_CONFIG 0
	17	#define BPDU_TYPE_TCN 0x80
	18
	19	struct stp_header {
	20	uint8_t dsap;
	21	uint8_t ssap;
	22	uint8_t ctrl;
	23	uint8_t pid;
	24	uint8_t vers;
	25	uint8_t type;
	26	};
	27
	28	struct stp_config_pdu {
	29	uint8_t flags;
	30	uint8_t root[8];
	31	uint8_t root_cost[4];
	32	uint8_t sender[8];
	33	uint8_t port[2];
	34	uint8_t msg_age[2];
	35	uint8_t max_age[2];
	36	uint8_t hello_time[2];
	37	uint8_t forward_delay[2];
	38	};
	39
	40	#define NR16(p) (p[0] << 8 \| p[1])
	41	#define NR32(p) ((p[0] << 24) \| (p[1] << 16) \| (p[2] << 8) \| p[3])
	42
8cc784ee	43	static bool ebt_filter_config(const struct ebt_stp_info *info,
abfdf1c4	44	const struct stp_config_pdu *stpc)
1da177e4	45	{
abfdf1c4	46	const struct ebt_stp_config_info *c;
1da177e4 LT	47	uint16_t v16;
	48	uint32_t v32;
	49	int verdict, i;
	50
	51	c = &info->config;
	52	if ((info->bitmask & EBT_STP_FLAGS) &&
	53	FWINV(c->flags != stpc->flags, EBT_STP_FLAGS))
8cc784ee	54	return false;
1da177e4 LT	55	if (info->bitmask & EBT_STP_ROOTPRIO) {
	56	v16 = NR16(stpc->root);
	57	if (FWINV(v16 < c->root_priol \|\|
	58	v16 > c->root_priou, EBT_STP_ROOTPRIO))
8cc784ee	59	return false;
1da177e4 LT	60	}
	61	if (info->bitmask & EBT_STP_ROOTADDR) {
	62	verdict = 0;
	63	for (i = 0; i < 6; i++)
	64	verdict \|= (stpc->root[2+i] ^ c->root_addr[i]) &
9d6f229f	65	c->root_addrmsk[i];
1da177e4	66	if (FWINV(verdict != 0, EBT_STP_ROOTADDR))
8cc784ee	67	return false;
1da177e4 LT	68	}
	69	if (info->bitmask & EBT_STP_ROOTCOST) {
	70	v32 = NR32(stpc->root_cost);
	71	if (FWINV(v32 < c->root_costl \|\|
	72	v32 > c->root_costu, EBT_STP_ROOTCOST))
8cc784ee	73	return false;
1da177e4 LT	74	}
	75	if (info->bitmask & EBT_STP_SENDERPRIO) {
	76	v16 = NR16(stpc->sender);
	77	if (FWINV(v16 < c->sender_priol \|\|
	78	v16 > c->sender_priou, EBT_STP_SENDERPRIO))
8cc784ee	79	return false;
1da177e4 LT	80	}
	81	if (info->bitmask & EBT_STP_SENDERADDR) {
	82	verdict = 0;
	83	for (i = 0; i < 6; i++)
	84	verdict \|= (stpc->sender[2+i] ^ c->sender_addr[i]) &
9d6f229f	85	c->sender_addrmsk[i];
1da177e4	86	if (FWINV(verdict != 0, EBT_STP_SENDERADDR))
8cc784ee	87	return false;
1da177e4 LT	88	}
	89	if (info->bitmask & EBT_STP_PORT) {
	90	v16 = NR16(stpc->port);
	91	if (FWINV(v16 < c->portl \|\|
	92	v16 > c->portu, EBT_STP_PORT))
8cc784ee	93	return false;
1da177e4 LT	94	}
	95	if (info->bitmask & EBT_STP_MSGAGE) {
	96	v16 = NR16(stpc->msg_age);
	97	if (FWINV(v16 < c->msg_agel \|\|
	98	v16 > c->msg_ageu, EBT_STP_MSGAGE))
8cc784ee	99	return false;
1da177e4 LT	100	}
	101	if (info->bitmask & EBT_STP_MAXAGE) {
	102	v16 = NR16(stpc->max_age);
	103	if (FWINV(v16 < c->max_agel \|\|
	104	v16 > c->max_ageu, EBT_STP_MAXAGE))
8cc784ee	105	return false;
1da177e4 LT	106	}
	107	if (info->bitmask & EBT_STP_HELLOTIME) {
	108	v16 = NR16(stpc->hello_time);
	109	if (FWINV(v16 < c->hello_timel \|\|
	110	v16 > c->hello_timeu, EBT_STP_HELLOTIME))
8cc784ee	111	return false;
1da177e4 LT	112	}
	113	if (info->bitmask & EBT_STP_FWDD) {
	114	v16 = NR16(stpc->forward_delay);
	115	if (FWINV(v16 < c->forward_delayl \|\|
	116	v16 > c->forward_delayu, EBT_STP_FWDD))
8cc784ee	117	return false;
1da177e4	118	}
8cc784ee	119	return true;
1da177e4 LT	120	}
1da177e4 LT	121
8cc784ee JE	122	static bool ebt_filter_stp(const struct sk_buff *skb,
8cc784ee JE	123	const struct net_device *in,
1da177e4 LT	124	const struct net_device out, const void data, unsigned int datalen)
1da177e4 LT	125	{
abfdf1c4 JE	126	const struct ebt_stp_info *info = data;
	127	const struct stp_header *sp;
	128	struct stp_header _stph;
	129	const uint8_t header[6] = {0x42, 0x42, 0x03, 0x00, 0x00, 0x00};
1da177e4 LT	130
	131	sp = skb_header_pointer(skb, 0, sizeof(_stph), &_stph);
	132	if (sp == NULL)
8cc784ee	133	return false;
1da177e4 LT	134
	135	/* The stp code only considers these */
	136	if (memcmp(sp, header, sizeof(header)))
8cc784ee	137	return false;
1da177e4 LT	138
	139	if (info->bitmask & EBT_STP_TYPE
	140	&& FWINV(info->type != sp->type, EBT_STP_TYPE))
8cc784ee	141	return false;
1da177e4 LT	142
	143	if (sp->type == BPDU_TYPE_CONFIG &&
	144	info->bitmask & EBT_STP_CONFIG_MASK) {
abfdf1c4 JE	145	const struct stp_config_pdu *st;
abfdf1c4 JE	146	struct stp_config_pdu _stpc;
1da177e4 LT	147
	148	st = skb_header_pointer(skb, sizeof(_stph),
	149	sizeof(_stpc), &_stpc);
	150	if (st == NULL)
8cc784ee	151	return false;
1da177e4 LT	152	return ebt_filter_config(info, st);
1da177e4 LT	153	}
8cc784ee	154	return true;
1da177e4 LT	155	}
1da177e4 LT	156
19eda879	157	static bool ebt_stp_check(const char *tablename, unsigned int hookmask,
1da177e4 LT	158	const struct ebt_entry e, void data, unsigned int datalen)
1da177e4 LT	159	{
abfdf1c4	160	const struct ebt_stp_info *info = data;
abfdf1c4 JE	161	const uint8_t bridge_ula[6] = {0x01, 0x80, 0xc2, 0x00, 0x00, 0x00};
abfdf1c4 JE	162	const uint8_t msk[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
1da177e4 LT	163
	164	if (info->bitmask & ~EBT_STP_MASK \|\| info->invflags & ~EBT_STP_MASK \|\|
	165	!(info->bitmask & EBT_STP_MASK))
19eda879	166	return false;
1da177e4	167	/* Make sure the match only receives stp frames */
d3f4a687 KK	168	if (compare_ether_addr(e->destmac, bridge_ula) \|\|
d3f4a687 KK	169	compare_ether_addr(e->destmsk, msk) \|\| !(e->bitmask & EBT_DESTMAC))
19eda879	170	return false;
1da177e4	171
19eda879	172	return true;
1da177e4 LT	173	}
1da177e4 LT	174
30083c95	175	static struct ebt_match filter_stp __read_mostly = {
1da177e4	176	.name = EBT_STP_MATCH,
001a18d3 JE	177	.revision = 0,
001a18d3 JE	178	.family = NFPROTO_BRIDGE,
1da177e4 LT	179	.match = ebt_filter_stp,
1da177e4 LT	180	.check = ebt_stp_check,
18219d3f	181	.matchsize = XT_ALIGN(sizeof(struct ebt_stp_info)),
1da177e4 LT	182	.me = THIS_MODULE,
	183	};
	184
65b4b4e8	185	static int __init ebt_stp_init(void)
1da177e4 LT	186	{
	187	return ebt_register_match(&filter_stp);
	188	}
	189
65b4b4e8	190	static void __exit ebt_stp_fini(void)
1da177e4 LT	191	{
	192	ebt_unregister_match(&filter_stp);
	193	}
	194
65b4b4e8 AM	195	module_init(ebt_stp_init);
65b4b4e8 AM	196	module_exit(ebt_stp_fini);
f776c4cd	197	MODULE_DESCRIPTION("Ebtables: Spanning Tree Protocol packet match");
1da177e4	198	MODULE_LICENSE("GPL");