[mirror_ubuntu-zesty-kernel.git] / net / bridge / br_stp_if.c

/*
 *	Spanning tree protocol; interface code
 *	Linux ethernet bridge
 *
 *	Authors:
 *	Lennert Buytenhek		<buytenh@gnu.org>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>

#include "br_private.h"
#include "br_private_stp.h"


/* Port id is composed of priority and port number.
 * NB: some bits of priority are dropped to
 *     make room for more ports.
 */
static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
{
	return ((u16)priority << BR_PORT_BITS)
		| (port_no & ((1<<BR_PORT_BITS)-1));
}

#define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)

/* called under bridge lock */
void br_init_port(struct net_bridge_port *p)
{
	p->port_id = br_make_port_id(p->priority, p->port_no);
	br_become_designated_port(p);
	br_set_state(p, BR_STATE_BLOCKING);
	p->topology_change_ack = 0;
	p->config_pending = 0;
}

/* called under bridge lock */
void br_stp_enable_bridge(struct net_bridge *br)
{
	struct net_bridge_port *p;

	spin_lock_bh(&br->lock);
	if (br->stp_enabled == BR_KERNEL_STP)
		mod_timer(&br->hello_timer, jiffies + br->hello_time);
	mod_timer(&br->gc_timer, jiffies + HZ/10);

	br_config_bpdu_generation(br);

	list_for_each_entry(p, &br->port_list, list) {
		if (netif_running(p->dev) && netif_oper_up(p->dev))
			br_stp_enable_port(p);

	}
	spin_unlock_bh(&br->lock);
}

/* NO locks held */
void br_stp_disable_bridge(struct net_bridge *br)
{
	struct net_bridge_port *p;

	spin_lock_bh(&br->lock);
	list_for_each_entry(p, &br->port_list, list) {
		if (p->state != BR_STATE_DISABLED)
			br_stp_disable_port(p);

	}

	br->topology_change = 0;
	br->topology_change_detected = 0;
	spin_unlock_bh(&br->lock);

	del_timer_sync(&br->hello_timer);
	del_timer_sync(&br->topology_change_timer);
	del_timer_sync(&br->tcn_timer);
	del_timer_sync(&br->gc_timer);
}

/* called under bridge lock */
void br_stp_enable_port(struct net_bridge_port *p)
{
	br_init_port(p);
	br_port_state_selection(p->br);
	br_log_state(p);
	br_ifinfo_notify(RTM_NEWLINK, p);
}

/* called under bridge lock */
void br_stp_disable_port(struct net_bridge_port *p)
{
	struct net_bridge *br = p->br;
	int wasroot;

	wasroot = br_is_root_bridge(br);
	br_become_designated_port(p);
	br_set_state(p, BR_STATE_DISABLED);
	p->topology_change_ack = 0;
	p->config_pending = 0;

	br_log_state(p);
	br_ifinfo_notify(RTM_NEWLINK, p);

	del_timer(&p->message_age_timer);
	del_timer(&p->forward_delay_timer);
	del_timer(&p->hold_timer);

	br_fdb_delete_by_port(br, p, 0, 0);
	br_multicast_disable_port(p);

	br_configuration_update(br);

	br_port_state_selection(br);

	if (br_is_root_bridge(br) && !wasroot)
		br_become_root_bridge(br);
}

static void br_stp_start(struct net_bridge *br)
{
	int r;
	char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
	char *envp[] = { NULL };
	struct net_bridge_port *p;

	r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);

	spin_lock_bh(&br->lock);

	if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
		__br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
	else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
		__br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);

	if (r == 0) {
		br->stp_enabled = BR_USER_STP;
		br_debug(br, "userspace STP started\n");
		/* Stop hello and hold timers */
		del_timer(&br->hello_timer);
		list_for_each_entry(p, &br->port_list, list)
			del_timer(&p->hold_timer);
	} else {
		br->stp_enabled = BR_KERNEL_STP;
		br_debug(br, "using kernel STP\n");

		/* To start timers on any ports left in blocking */
		br_port_state_selection(br);
	}

	spin_unlock_bh(&br->lock);
}

static void br_stp_stop(struct net_bridge *br)
{
	int r;
	char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
	char *envp[] = { NULL };
	struct net_bridge_port *p;

	if (br->stp_enabled == BR_USER_STP) {
		r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
		br_info(br, "userspace STP stopped, return code %d\n", r);

		/* To start timers on any ports left in blocking */
		mod_timer(&br->hello_timer, jiffies + br->hello_time);
		list_for_each_entry(p, &br->port_list, list)
			mod_timer(&p->hold_timer,
				  round_jiffies(jiffies + BR_HOLD_TIME));
		spin_lock_bh(&br->lock);
		br_port_state_selection(br);
		spin_unlock_bh(&br->lock);
	}

	br->stp_enabled = BR_NO_STP;
}

void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
{
	ASSERT_RTNL();

	if (val) {
		if (br->stp_enabled == BR_NO_STP)
			br_stp_start(br);
	} else {
		if (br->stp_enabled != BR_NO_STP)
			br_stp_stop(br);
	}
}

/* called under bridge lock */
void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
{
	/* should be aligned on 2 bytes for ether_addr_equal() */
	unsigned short oldaddr_aligned[ETH_ALEN >> 1];
	unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
	struct net_bridge_port *p;
	int wasroot;

	wasroot = br_is_root_bridge(br);

	br_fdb_change_mac_address(br, addr);

	memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
	memcpy(br->bridge_id.addr, addr, ETH_ALEN);
	memcpy(br->dev->dev_addr, addr, ETH_ALEN);

	list_for_each_entry(p, &br->port_list, list) {
		if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
			memcpy(p->designated_bridge.addr, addr, ETH_ALEN);

		if (ether_addr_equal(p->designated_root.addr, oldaddr))
			memcpy(p->designated_root.addr, addr, ETH_ALEN);
	}

	br_configuration_update(br);
	br_port_state_selection(br);
	if (br_is_root_bridge(br) && !wasroot)
		br_become_root_bridge(br);
}

/* should be aligned on 2 bytes for ether_addr_equal() */
static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];

/* called under bridge lock */
bool br_stp_recalculate_bridge_id(struct net_bridge *br)
{
	const unsigned char *br_mac_zero =
			(const unsigned char *)br_mac_zero_aligned;
	const unsigned char *addr = br_mac_zero;
	struct net_bridge_port *p;

	/* user has chosen a value so keep it */
	if (br->dev->addr_assign_type == NET_ADDR_SET)
		return false;

	list_for_each_entry(p, &br->port_list, list) {
		if (addr == br_mac_zero ||
		    memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
			addr = p->dev->dev_addr;

	}

	if (ether_addr_equal(br->bridge_id.addr, addr))
		return false;	/* no change */

	br_stp_change_bridge_id(br, addr);
	return true;
}

/* Acquires and releases bridge lock */
void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
{
	struct net_bridge_port *p;
	int wasroot;

	spin_lock_bh(&br->lock);
	wasroot = br_is_root_bridge(br);

	list_for_each_entry(p, &br->port_list, list) {
		if (p->state != BR_STATE_DISABLED &&
		    br_is_designated_port(p)) {
			p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
			p->designated_bridge.prio[1] = newprio & 0xFF;
		}

	}

	br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
	br->bridge_id.prio[1] = newprio & 0xFF;
	br_configuration_update(br);
	br_port_state_selection(br);
	if (br_is_root_bridge(br) && !wasroot)
		br_become_root_bridge(br);
	spin_unlock_bh(&br->lock);
}

/* called under bridge lock */
int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
{
	port_id new_port_id;

	if (newprio > BR_MAX_PORT_PRIORITY)
		return -ERANGE;

	new_port_id = br_make_port_id(newprio, p->port_no);
	if (br_is_designated_port(p))
		p->designated_port = new_port_id;

	p->port_id = new_port_id;
	p->priority = newprio;
	if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
	    p->port_id < p->designated_port) {
		br_become_designated_port(p);
		br_port_state_selection(p->br);
	}

	return 0;
}

/* called under bridge lock */
int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
{
	if (path_cost < BR_MIN_PATH_COST ||
	    path_cost > BR_MAX_PATH_COST)
		return -ERANGE;

	p->flags |= BR_ADMIN_COST;
	p->path_cost = path_cost;
	br_configuration_update(p->br);
	br_port_state_selection(p->br);
	return 0;
}

ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
{
	return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
	       id->prio[0], id->prio[1],
	       id->addr[0], id->addr[1], id->addr[2],
	       id->addr[3], id->addr[4], id->addr[5]);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Spanning tree protocol; interface code
	3	* Linux ethernet bridge
	4	*
	5	* Authors:
	6	* Lennert Buytenhek <buytenh@gnu.org>
	7	*
1da177e4 LT	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License
	10	* as published by the Free Software Foundation; either version
	11	* 2 of the License, or (at your option) any later version.
	12	*/
	13
	14	#include <linux/kernel.h>
79bb1ee4	15	#include <linux/kmod.h>
6ede2463	16	#include <linux/etherdevice.h>
11dc1f36	17	#include <linux/rtnetlink.h>
1da177e4 LT	18
	19	#include "br_private.h"
	20	#include "br_private_stp.h"
	21
	22
	23	/* Port id is composed of priority and port number.
14f98f25	24	* NB: some bits of priority are dropped to
1da177e4 LT	25	* make room for more ports.
	26	*/
	27	static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
	28	{
9d6f229f	29	return ((u16)priority << BR_PORT_BITS)
1da177e4 LT	30	\| (port_no & ((1<<BR_PORT_BITS)-1));
	31	}
	32
14f98f25	33	#define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)
14f98f25	34
1da177e4 LT	35	/* called under bridge lock */
	36	void br_init_port(struct net_bridge_port *p)
	37	{
	38	p->port_id = br_make_port_id(p->priority, p->port_no);
	39	br_become_designated_port(p);
775dd692	40	br_set_state(p, BR_STATE_BLOCKING);
1da177e4 LT	41	p->topology_change_ack = 0;
1da177e4 LT	42	p->config_pending = 0;
1da177e4 LT	43	}
	44
	45	/* called under bridge lock */
	46	void br_stp_enable_bridge(struct net_bridge *br)
	47	{
	48	struct net_bridge_port *p;
	49
	50	spin_lock_bh(&br->lock);
76b91c32 NA	51	if (br->stp_enabled == BR_KERNEL_STP)
76b91c32 NA	52	mod_timer(&br->hello_timer, jiffies + br->hello_time);
1da177e4	53	mod_timer(&br->gc_timer, jiffies + HZ/10);
9d6f229f	54
1da177e4 LT	55	br_config_bpdu_generation(br);
	56
	57	list_for_each_entry(p, &br->port_list, list) {
576eb625	58	if (netif_running(p->dev) && netif_oper_up(p->dev))
1da177e4 LT	59	br_stp_enable_port(p);
	60
	61	}
	62	spin_unlock_bh(&br->lock);
	63	}
	64
	65	/* NO locks held */
	66	void br_stp_disable_bridge(struct net_bridge *br)
	67	{
	68	struct net_bridge_port *p;
	69
78872ccb	70	spin_lock_bh(&br->lock);
1da177e4 LT	71	list_for_each_entry(p, &br->port_list, list) {
	72	if (p->state != BR_STATE_DISABLED)
	73	br_stp_disable_port(p);
	74
	75	}
	76
	77	br->topology_change = 0;
	78	br->topology_change_detected = 0;
78872ccb	79	spin_unlock_bh(&br->lock);
1da177e4 LT	80
	81	del_timer_sync(&br->hello_timer);
	82	del_timer_sync(&br->topology_change_timer);
	83	del_timer_sync(&br->tcn_timer);
	84	del_timer_sync(&br->gc_timer);
	85	}
	86
	87	/* called under bridge lock */
	88	void br_stp_enable_port(struct net_bridge_port *p)
	89	{
	90	br_init_port(p);
	91	br_port_state_selection(p->br);
28a16c97	92	br_log_state(p);
4ecb961c	93	br_ifinfo_notify(RTM_NEWLINK, p);
1da177e4 LT	94	}
	95
	96	/* called under bridge lock */
	97	void br_stp_disable_port(struct net_bridge_port *p)
	98	{
28a16c97	99	struct net_bridge *br = p->br;
1da177e4 LT	100	int wasroot;
1da177e4 LT	101
1da177e4 LT	102	wasroot = br_is_root_bridge(br);
1da177e4 LT	103	br_become_designated_port(p);
775dd692	104	br_set_state(p, BR_STATE_DISABLED);
1da177e4 LT	105	p->topology_change_ack = 0;
	106	p->config_pending = 0;
	107
5200959b	108	br_log_state(p);
4ecb961c	109	br_ifinfo_notify(RTM_NEWLINK, p);
4ecb961c	110
1da177e4 LT	111	del_timer(&p->message_age_timer);
	112	del_timer(&p->forward_delay_timer);
	113	del_timer(&p->hold_timer);
	114
1ea2d020	115	br_fdb_delete_by_port(br, p, 0, 0);
3fe2d7c7	116	br_multicast_disable_port(p);
1a620698	117
1da177e4 LT	118	br_configuration_update(br);
	119
	120	br_port_state_selection(br);
	121
	122	if (br_is_root_bridge(br) && !wasroot)
	123	br_become_root_bridge(br);
	124	}
	125
9cde0708 SH	126	static void br_stp_start(struct net_bridge *br)
	127	{
	128	int r;
	129	char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
	130	char *envp[] = { NULL };
76b91c32	131	struct net_bridge_port *p;
9cde0708	132
86313c48	133	r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
be4f154d HX	134
	135	spin_lock_bh(&br->lock);
	136
	137	if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
	138	__br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
4b6c7879	139	else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
be4f154d HX	140	__br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
be4f154d HX	141
9cde0708 SH	142	if (r == 0) {
9cde0708 SH	143	br->stp_enabled = BR_USER_STP;
28a16c97	144	br_debug(br, "userspace STP started\n");
76b91c32 NA	145	/* Stop hello and hold timers */
	146	del_timer(&br->hello_timer);
	147	list_for_each_entry(p, &br->port_list, list)
	148	del_timer(&p->hold_timer);
9cde0708 SH	149	} else {
9cde0708 SH	150	br->stp_enabled = BR_KERNEL_STP;
28a16c97	151	br_debug(br, "using kernel STP\n");
9cde0708 SH	152
9cde0708 SH	153	/* To start timers on any ports left in blocking */
9cde0708	154	br_port_state_selection(br);
9cde0708	155	}
be4f154d HX	156
be4f154d HX	157	spin_unlock_bh(&br->lock);
9cde0708 SH	158	}
	159
	160	static void br_stp_stop(struct net_bridge *br)
	161	{
	162	int r;
	163	char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
	164	char *envp[] = { NULL };
76b91c32	165	struct net_bridge_port *p;
9cde0708 SH	166
9cde0708 SH	167	if (br->stp_enabled == BR_USER_STP) {
1a9180a2	168	r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
28a16c97	169	br_info(br, "userspace STP stopped, return code %d\n", r);
9cde0708 SH	170
9cde0708 SH	171	/* To start timers on any ports left in blocking */
76b91c32 NA	172	mod_timer(&br->hello_timer, jiffies + br->hello_time);
	173	list_for_each_entry(p, &br->port_list, list)
	174	mod_timer(&p->hold_timer,
	175	round_jiffies(jiffies + BR_HOLD_TIME));
9cde0708 SH	176	spin_lock_bh(&br->lock);
	177	br_port_state_selection(br);
	178	spin_unlock_bh(&br->lock);
	179	}
	180
	181	br->stp_enabled = BR_NO_STP;
	182	}
	183
	184	void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
	185	{
	186	ASSERT_RTNL();
	187
	188	if (val) {
	189	if (br->stp_enabled == BR_NO_STP)
	190	br_stp_start(br);
	191	} else {
	192	if (br->stp_enabled != BR_NO_STP)
	193	br_stp_stop(br);
	194	}
	195	}
	196
1da177e4	197	/* called under bridge lock */
4505a3ef	198	void br_stp_change_bridge_id(struct net_bridge br, const unsigned char addr)
1da177e4	199	{
9a7b6ef9	200	/* should be aligned on 2 bytes for ether_addr_equal() */
19bb3506 EK	201	unsigned short oldaddr_aligned[ETH_ALEN >> 1];
19bb3506 EK	202	unsigned char oldaddr = (unsigned char )oldaddr_aligned;
1da177e4 LT	203	struct net_bridge_port *p;
	204	int wasroot;
	205
	206	wasroot = br_is_root_bridge(br);
	207
a4b816d8 TM	208	br_fdb_change_mac_address(br, addr);
a4b816d8 TM	209
1da177e4 LT	210	memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
	211	memcpy(br->bridge_id.addr, addr, ETH_ALEN);
	212	memcpy(br->dev->dev_addr, addr, ETH_ALEN);
	213
	214	list_for_each_entry(p, &br->port_list, list) {
9a7b6ef9	215	if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
1da177e4 LT	216	memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
1da177e4 LT	217
9a7b6ef9	218	if (ether_addr_equal(p->designated_root.addr, oldaddr))
1da177e4	219	memcpy(p->designated_root.addr, addr, ETH_ALEN);
1da177e4 LT	220	}
	221
	222	br_configuration_update(br);
	223	br_port_state_selection(br);
	224	if (br_is_root_bridge(br) && !wasroot)
	225	br_become_root_bridge(br);
	226	}
	227
9a7b6ef9	228	/* should be aligned on 2 bytes for ether_addr_equal() */
19bb3506	229	static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
1da177e4 LT	230
1da177e4 LT	231	/* called under bridge lock */
edf947f1	232	bool br_stp_recalculate_bridge_id(struct net_bridge *br)
1da177e4	233	{
19bb3506 EK	234	const unsigned char *br_mac_zero =
19bb3506 EK	235	(const unsigned char *)br_mac_zero_aligned;
1da177e4 LT	236	const unsigned char *addr = br_mac_zero;
	237	struct net_bridge_port *p;
	238
92c0574f	239	/* user has chosen a value so keep it */
b2748267	240	if (br->dev->addr_assign_type == NET_ADDR_SET)
1459a3cc	241	return false;
92c0574f	242
1da177e4 LT	243	list_for_each_entry(p, &br->port_list, list) {
1da177e4 LT	244	if (addr == br_mac_zero \|\|
554c9a8e	245	memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
1da177e4 LT	246	addr = p->dev->dev_addr;
	247
	248	}
	249
9a7b6ef9	250	if (ether_addr_equal(br->bridge_id.addr, addr))
edf947f1	251	return false; /* no change */
	252
	253	br_stp_change_bridge_id(br, addr);
	254	return true;
1da177e4 LT	255	}
1da177e4 LT	256
2dab80a8	257	/* Acquires and releases bridge lock */
1da177e4 LT	258	void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
	259	{
	260	struct net_bridge_port *p;
	261	int wasroot;
	262
2dab80a8	263	spin_lock_bh(&br->lock);
1da177e4 LT	264	wasroot = br_is_root_bridge(br);
	265
	266	list_for_each_entry(p, &br->port_list, list) {
	267	if (p->state != BR_STATE_DISABLED &&
	268	br_is_designated_port(p)) {
	269	p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
	270	p->designated_bridge.prio[1] = newprio & 0xFF;
	271	}
	272
	273	}
	274
	275	br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
	276	br->bridge_id.prio[1] = newprio & 0xFF;
	277	br_configuration_update(br);
	278	br_port_state_selection(br);
	279	if (br_is_root_bridge(br) && !wasroot)
	280	br_become_root_bridge(br);
2dab80a8	281	spin_unlock_bh(&br->lock);
1da177e4 LT	282	}
	283
	284	/* called under bridge lock */
14f98f25	285	int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
1da177e4	286	{
14f98f25	287	port_id new_port_id;
	288
	289	if (newprio > BR_MAX_PORT_PRIORITY)
	290	return -ERANGE;
1da177e4	291
14f98f25	292	new_port_id = br_make_port_id(newprio, p->port_no);
1da177e4 LT	293	if (br_is_designated_port(p))
	294	p->designated_port = new_port_id;
	295
	296	p->port_id = new_port_id;
	297	p->priority = newprio;
	298	if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
	299	p->port_id < p->designated_port) {
	300	br_become_designated_port(p);
	301	br_port_state_selection(p->br);
	302	}
14f98f25	303
14f98f25	304	return 0;
1da177e4 LT	305	}
	306
	307	/* called under bridge lock */
14f98f25	308	int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
1da177e4	309	{
14f98f25	310	if (path_cost < BR_MIN_PATH_COST \|\|
	311	path_cost > BR_MAX_PATH_COST)
	312	return -ERANGE;
	313
8f3359bd	314	p->flags \|= BR_ADMIN_COST;
1da177e4 LT	315	p->path_cost = path_cost;
	316	br_configuration_update(p->br);
	317	br_port_state_selection(p->br);
14f98f25	318	return 0;
1da177e4 LT	319	}
	320
	321	ssize_t br_show_bridge_id(char buf, const struct bridge_id id)
	322	{
	323	return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
	324	id->prio[0], id->prio[1],
	325	id->addr[0], id->addr[1], id->addr[2],
	326	id->addr[3], id->addr[4], id->addr[5]);
	327	}