Release 4.7 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;
}

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static bool

ebt_stp_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct ebt_stp_info *info = par->matchinfo;
	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;
}

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david s. miller
37
19.27%
1
14.29%
jan engelhardt
jan engelhardt
24
12.50%
5
71.43%
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192
100.00%
7
100.00%



static int ebt_stp_mt_check(const struct xt_mtchk_param *par)
{
	const struct ebt_stp_info *info = par->matchinfo;
	const uint8_t bridge_ula[6] = {0x01, 0x80, 0xc2, 0x00, 0x00, 0x00};
	const uint8_t msk[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
	const struct ebt_entry *e = par->entryinfo;

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

	return 0;
}

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jan engelhardt
jan engelhardt
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16.78%
5
62.50%
pablo neira ayuso
pablo neira ayuso
7
4.70%
1
12.50%
joe perches
joe perches
4
2.68%
1
12.50%
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149
100.00%
8
100.00%


static struct xt_match ebt_stp_mt_reg __read_mostly = {
	.name		= "stp",
	.revision	= 0,
	.family		= NFPROTO_BRIDGE,
	.match		= ebt_stp_mt,
	.checkentry	= ebt_stp_mt_check,
	.matchsize	= sizeof(struct ebt_stp_info),
	.me		= THIS_MODULE,
};



static int __init ebt_stp_init(void)
{
	return xt_register_match(&ebt_stp_mt_reg);
}

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jan engelhardt
2
12.50%
1
33.33%
andrew morton
andrew morton
1
6.25%
1
33.33%
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static void __exit ebt_stp_fini(void)
{
	xt_unregister_match(&ebt_stp_mt_reg);
}

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bart de schuymer
bart de schuymer
12
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1
33.33%
jan engelhardt
jan engelhardt
2
13.33%
1
33.33%
andrew morton
andrew morton
1
6.67%
1
33.33%
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100.00%
3
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module_init(ebt_stp_init);

module_exit(ebt_stp_fini);
MODULE_DESCRIPTION("Ebtables: Spanning Tree Protocol packet match");
MODULE_LICENSE("GPL");
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bart de schuymer
930
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5.26%
jan engelhardt
jan engelhardt
107
9.81%
13
68.42%
david s. miller
david s. miller
39
3.57%
2
10.53%
pablo neira ayuso
pablo neira ayuso
7
0.64%
1
5.26%
joe perches
joe perches
4
0.37%
1
5.26%
andrew morton
andrew morton
4
0.37%
1
5.26%
Total
1091
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19
100.00%
  
Directory: net/bridge/netfilter

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