[deliverable/linux.git] / net / bridge / br_stp.c

/*
 *	Spanning tree protocol; generic parts
 *	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 "br_private.h"
#include "br_private_stp.h"

/* since time values in bpdu are in jiffies and then scaled (1/256)
 * before sending, make sure that is at least one.
 */
#define MESSAGE_AGE_INCR	((HZ < 256) ? 1 : (HZ/256))

static const char *br_port_state_names[] = {
	[BR_STATE_DISABLED] = "disabled",
	[BR_STATE_LISTENING] = "listening",
	[BR_STATE_LEARNING] = "learning",
	[BR_STATE_FORWARDING] = "forwarding",
	[BR_STATE_BLOCKING] = "blocking",
};

void br_log_state(const struct net_bridge_port *p)
{
	pr_info("%s: port %d(%s) entering %s state\n",
		p->br->dev->name, p->port_no, p->dev->name,
		br_port_state_names[p->state]);

}

/* called under bridge lock */
struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no)
{
	struct net_bridge_port *p;

	list_for_each_entry_rcu(p, &br->port_list, list) {
		if (p->port_no == port_no)
			return p;
	}

	return NULL;
}

/* called under bridge lock */
static int br_should_become_root_port(const struct net_bridge_port *p,
				      u16 root_port)
{
	struct net_bridge *br;
	struct net_bridge_port *rp;
	int t;

	br = p->br;
	if (p->state == BR_STATE_DISABLED ||
	    br_is_designated_port(p))
		return 0;

	if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
		return 0;

	if (!root_port)
		return 1;

	rp = br_get_port(br, root_port);

	t = memcmp(&p->designated_root, &rp->designated_root, 8);
	if (t < 0)
		return 1;
	else if (t > 0)
		return 0;

	if (p->designated_cost + p->path_cost <
	    rp->designated_cost + rp->path_cost)
		return 1;
	else if (p->designated_cost + p->path_cost >
		 rp->designated_cost + rp->path_cost)
		return 0;

	t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
	if (t < 0)
		return 1;
	else if (t > 0)
		return 0;

	if (p->designated_port < rp->designated_port)
		return 1;
	else if (p->designated_port > rp->designated_port)
		return 0;

	if (p->port_id < rp->port_id)
		return 1;

	return 0;
}

/* called under bridge lock */
static void br_root_selection(struct net_bridge *br)
{
	struct net_bridge_port *p;
	u16 root_port = 0;

	list_for_each_entry(p, &br->port_list, list) {
		if (br_should_become_root_port(p, root_port))
			root_port = p->port_no;

	}

	br->root_port = root_port;

	if (!root_port) {
		br->designated_root = br->bridge_id;
		br->root_path_cost = 0;
	} else {
		p = br_get_port(br, root_port);
		br->designated_root = p->designated_root;
		br->root_path_cost = p->designated_cost + p->path_cost;
	}
}

/* called under bridge lock */
void br_become_root_bridge(struct net_bridge *br)
{
	br->max_age = br->bridge_max_age;
	br->hello_time = br->bridge_hello_time;
	br->forward_delay = br->bridge_forward_delay;
	br_topology_change_detection(br);
	del_timer(&br->tcn_timer);

	if (br->dev->flags & IFF_UP) {
		br_config_bpdu_generation(br);
		mod_timer(&br->hello_timer, jiffies + br->hello_time);
	}
}

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


	if (timer_pending(&p->hold_timer)) {
		p->config_pending = 1;
		return;
	}

	br = p->br;

	bpdu.topology_change = br->topology_change;
	bpdu.topology_change_ack = p->topology_change_ack;
	bpdu.root = br->designated_root;
	bpdu.root_path_cost = br->root_path_cost;
	bpdu.bridge_id = br->bridge_id;
	bpdu.port_id = p->port_id;
	if (br_is_root_bridge(br))
		bpdu.message_age = 0;
	else {
		struct net_bridge_port *root
			= br_get_port(br, br->root_port);
		bpdu.message_age = br->max_age
			- (root->message_age_timer.expires - jiffies)
			+ MESSAGE_AGE_INCR;
	}
	bpdu.max_age = br->max_age;
	bpdu.hello_time = br->hello_time;
	bpdu.forward_delay = br->forward_delay;

	if (bpdu.message_age < br->max_age) {
		br_send_config_bpdu(p, &bpdu);
		p->topology_change_ack = 0;
		p->config_pending = 0;
		mod_timer(&p->hold_timer,
			  round_jiffies(jiffies + BR_HOLD_TIME));
	}
}

/* called under bridge lock */
static inline void br_record_config_information(struct net_bridge_port *p,
						const struct br_config_bpdu *bpdu)
{
	p->designated_root = bpdu->root;
	p->designated_cost = bpdu->root_path_cost;
	p->designated_bridge = bpdu->bridge_id;
	p->designated_port = bpdu->port_id;

	mod_timer(&p->message_age_timer, jiffies
		  + (p->br->max_age - bpdu->message_age));
}

/* called under bridge lock */
static inline void br_record_config_timeout_values(struct net_bridge *br,
					    const struct br_config_bpdu *bpdu)
{
	br->max_age = bpdu->max_age;
	br->hello_time = bpdu->hello_time;
	br->forward_delay = bpdu->forward_delay;
	br->topology_change = bpdu->topology_change;
}

/* called under bridge lock */
void br_transmit_tcn(struct net_bridge *br)
{
	br_send_tcn_bpdu(br_get_port(br, br->root_port));
}

/* called under bridge lock */
static int br_should_become_designated_port(const struct net_bridge_port *p)
{
	struct net_bridge *br;
	int t;

	br = p->br;
	if (br_is_designated_port(p))
		return 1;

	if (memcmp(&p->designated_root, &br->designated_root, 8))
		return 1;

	if (br->root_path_cost < p->designated_cost)
		return 1;
	else if (br->root_path_cost > p->designated_cost)
		return 0;

	t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
	if (t < 0)
		return 1;
	else if (t > 0)
		return 0;

	if (p->port_id < p->designated_port)
		return 1;

	return 0;
}

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

	list_for_each_entry(p, &br->port_list, list) {
		if (p->state != BR_STATE_DISABLED &&
		    br_should_become_designated_port(p))
			br_become_designated_port(p);

	}
}

/* called under bridge lock */
static int br_supersedes_port_info(struct net_bridge_port *p, struct br_config_bpdu *bpdu)
{
	int t;

	t = memcmp(&bpdu->root, &p->designated_root, 8);
	if (t < 0)
		return 1;
	else if (t > 0)
		return 0;

	if (bpdu->root_path_cost < p->designated_cost)
		return 1;
	else if (bpdu->root_path_cost > p->designated_cost)
		return 0;

	t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
	if (t < 0)
		return 1;
	else if (t > 0)
		return 0;

	if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
		return 1;

	if (bpdu->port_id <= p->designated_port)
		return 1;

	return 0;
}

/* called under bridge lock */
static inline void br_topology_change_acknowledged(struct net_bridge *br)
{
	br->topology_change_detected = 0;
	del_timer(&br->tcn_timer);
}

/* called under bridge lock */
void br_topology_change_detection(struct net_bridge *br)
{
	int isroot = br_is_root_bridge(br);

	pr_info("%s: topology change detected, %s\n", br->dev->name,
		isroot ? "propagating" : "sending tcn bpdu");

	if (isroot) {
		br->topology_change = 1;
		mod_timer(&br->topology_change_timer, jiffies
			  + br->bridge_forward_delay + br->bridge_max_age);
	} else if (!br->topology_change_detected) {
		br_transmit_tcn(br);
		mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
	}

	br->topology_change_detected = 1;
}

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

	list_for_each_entry(p, &br->port_list, list) {
		if (p->state != BR_STATE_DISABLED &&
		    br_is_designated_port(p))
			br_transmit_config(p);
	}
}

/* called under bridge lock */
static inline void br_reply(struct net_bridge_port *p)
{
	br_transmit_config(p);
}

/* called under bridge lock */
void br_configuration_update(struct net_bridge *br)
{
	br_root_selection(br);
	br_designated_port_selection(br);
}

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

	br = p->br;
	p->designated_root = br->designated_root;
	p->designated_cost = br->root_path_cost;
	p->designated_bridge = br->bridge_id;
	p->designated_port = p->port_id;
}


/* called under bridge lock */
static void br_make_blocking(struct net_bridge_port *p)
{
	if (p->state != BR_STATE_DISABLED &&
	    p->state != BR_STATE_BLOCKING) {
		if (p->state == BR_STATE_FORWARDING ||
		    p->state == BR_STATE_LEARNING)
			br_topology_change_detection(p->br);

		p->state = BR_STATE_BLOCKING;
		br_log_state(p);
		del_timer(&p->forward_delay_timer);
	}
}

/* called under bridge lock */
static void br_make_forwarding(struct net_bridge_port *p)
{
	if (p->state == BR_STATE_BLOCKING) {
		if (p->br->stp_enabled == BR_KERNEL_STP)
			p->state = BR_STATE_LISTENING;
		else
			p->state = BR_STATE_LEARNING;

		br_log_state(p);
		mod_timer(&p->forward_delay_timer, jiffies + p->br->forward_delay);	}
}

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

	/* Don't change port states if userspace is handling STP */
	if (br->stp_enabled == BR_USER_STP)
		return;

	list_for_each_entry(p, &br->port_list, list) {
		if (p->state != BR_STATE_DISABLED) {
			if (p->port_no == br->root_port) {
				p->config_pending = 0;
				p->topology_change_ack = 0;
				br_make_forwarding(p);
			} else if (br_is_designated_port(p)) {
				del_timer(&p->message_age_timer);
				br_make_forwarding(p);
			} else {
				p->config_pending = 0;
				p->topology_change_ack = 0;
				br_make_blocking(p);
			}
		}

	}
}

/* called under bridge lock */
static inline void br_topology_change_acknowledge(struct net_bridge_port *p)
{
	p->topology_change_ack = 1;
	br_transmit_config(p);
}

/* called under bridge lock */
void br_received_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu)
{
	struct net_bridge *br;
	int was_root;

	br = p->br;
	was_root = br_is_root_bridge(br);

	if (br_supersedes_port_info(p, bpdu)) {
		br_record_config_information(p, bpdu);
		br_configuration_update(br);
		br_port_state_selection(br);

		if (!br_is_root_bridge(br) && was_root) {
			del_timer(&br->hello_timer);
			if (br->topology_change_detected) {
				del_timer(&br->topology_change_timer);
				br_transmit_tcn(br);

				mod_timer(&br->tcn_timer,
					  jiffies + br->bridge_hello_time);
			}
		}

		if (p->port_no == br->root_port) {
			br_record_config_timeout_values(br, bpdu);
			br_config_bpdu_generation(br);
			if (bpdu->topology_change_ack)
				br_topology_change_acknowledged(br);
		}
	} else if (br_is_designated_port(p)) {
		br_reply(p);
	}
}

/* called under bridge lock */
void br_received_tcn_bpdu(struct net_bridge_port *p)
{
	if (br_is_designated_port(p)) {
		pr_info("%s: received tcn bpdu on port %i(%s)\n",
		       p->br->dev->name, p->port_no, p->dev->name);

		br_topology_change_detection(p->br);
		br_topology_change_acknowledge(p);
	}
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Spanning tree protocol; generic parts
	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	#include <linux/kernel.h>
1da177e4 LT	14
	15	#include "br_private.h"
	16	#include "br_private_stp.h"
	17
	18	/* since time values in bpdu are in jiffies and then scaled (1/256)
	19	* before sending, make sure that is at least one.
	20	*/
	21	#define MESSAGE_AGE_INCR ((HZ < 256) ? 1 : (HZ/256))
	22
	23	static const char *br_port_state_names[] = {
9d6f229f	24	[BR_STATE_DISABLED] = "disabled",
1da177e4	25	[BR_STATE_LISTENING] = "listening",
9d6f229f YH	26	[BR_STATE_LEARNING] = "learning",
9d6f229f YH	27	[BR_STATE_FORWARDING] = "forwarding",
1da177e4 LT	28	[BR_STATE_BLOCKING] = "blocking",
	29	};
	30
	31	void br_log_state(const struct net_bridge_port *p)
	32	{
	33	pr_info("%s: port %d(%s) entering %s state\n",
9d6f229f	34	p->br->dev->name, p->port_no, p->dev->name,
1da177e4 LT	35	br_port_state_names[p->state]);
	36
	37	}
	38
	39	/* called under bridge lock */
	40	struct net_bridge_port br_get_port(struct net_bridge br, u16 port_no)
	41	{
	42	struct net_bridge_port *p;
	43
	44	list_for_each_entry_rcu(p, &br->port_list, list) {
	45	if (p->port_no == port_no)
	46	return p;
	47	}
	48
	49	return NULL;
	50	}
	51
	52	/* called under bridge lock */
9d6f229f	53	static int br_should_become_root_port(const struct net_bridge_port *p,
1da177e4 LT	54	u16 root_port)
	55	{
	56	struct net_bridge *br;
	57	struct net_bridge_port *rp;
	58	int t;
	59
	60	br = p->br;
	61	if (p->state == BR_STATE_DISABLED \|\|
	62	br_is_designated_port(p))
	63	return 0;
	64
	65	if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
	66	return 0;
	67
	68	if (!root_port)
	69	return 1;
	70
	71	rp = br_get_port(br, root_port);
	72
	73	t = memcmp(&p->designated_root, &rp->designated_root, 8);
	74	if (t < 0)
	75	return 1;
	76	else if (t > 0)
	77	return 0;
	78
	79	if (p->designated_cost + p->path_cost <
	80	rp->designated_cost + rp->path_cost)
	81	return 1;
	82	else if (p->designated_cost + p->path_cost >
	83	rp->designated_cost + rp->path_cost)
	84	return 0;
	85
	86	t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
	87	if (t < 0)
	88	return 1;
	89	else if (t > 0)
	90	return 0;
	91
	92	if (p->designated_port < rp->designated_port)
	93	return 1;
	94	else if (p->designated_port > rp->designated_port)
	95	return 0;
	96
	97	if (p->port_id < rp->port_id)
	98	return 1;
	99
	100	return 0;
	101	}
	102
	103	/* called under bridge lock */
	104	static void br_root_selection(struct net_bridge *br)
	105	{
	106	struct net_bridge_port *p;
	107	u16 root_port = 0;
	108
	109	list_for_each_entry(p, &br->port_list, list) {
	110	if (br_should_become_root_port(p, root_port))
	111	root_port = p->port_no;
	112
	113	}
	114
	115	br->root_port = root_port;
	116
	117	if (!root_port) {
118	br->designated_root = br->bridge_id;
119	br->root_path_cost = 0;
120	} else {
121	p = br_get_port(br, root_port);
122	br->designated_root = p->designated_root;
123	br->root_path_cost = p->designated_cost + p->path_cost;
124	}
125	}
126
127	/* called under bridge lock */
128	void br_become_root_bridge(struct net_bridge *br)
129	{
130	br->max_age = br->bridge_max_age;
131	br->hello_time = br->bridge_hello_time;
132	br->forward_delay = br->bridge_forward_delay;
133	br_topology_change_detection(br);
134	del_timer(&br->tcn_timer);
135
136	if (br->dev->flags & IFF_UP) {
137	br_config_bpdu_generation(br);
138	mod_timer(&br->hello_timer, jiffies + br->hello_time);
139	}
140	}
141
142	/* called under bridge lock */
143	void br_transmit_config(struct net_bridge_port *p)
144	{
145	struct br_config_bpdu bpdu;
146	struct net_bridge *br;
147
148
149	if (timer_pending(&p->hold_timer)) {
150	p->config_pending = 1;
151	return;
152	}
153
154	br = p->br;
155
156	bpdu.topology_change = br->topology_change;
157	bpdu.topology_change_ack = p->topology_change_ack;
158	bpdu.root = br->designated_root;
159	bpdu.root_path_cost = br->root_path_cost;
160	bpdu.bridge_id = br->bridge_id;
161	bpdu.port_id = p->port_id;
162	if (br_is_root_bridge(br))
163	bpdu.message_age = 0;
164	else {
165	struct net_bridge_port *root
166	= br_get_port(br, br->root_port);
167	bpdu.message_age = br->max_age
168	- (root->message_age_timer.expires - jiffies)
169	+ MESSAGE_AGE_INCR;
170	}
171	bpdu.max_age = br->max_age;
172	bpdu.hello_time = br->hello_time;
173	bpdu.forward_delay = br->forward_delay;
174
175	if (bpdu.message_age < br->max_age) {
176	br_send_config_bpdu(p, &bpdu);
177	p->topology_change_ack = 0;
178	p->config_pending = 0;
9a834b87 SH	179	mod_timer(&p->hold_timer,
9a834b87 SH	180	round_jiffies(jiffies + BR_HOLD_TIME));
1da177e4 LT	181	}
	182	}
	183
	184	/* called under bridge lock */
9d6f229f	185	static inline void br_record_config_information(struct net_bridge_port *p,
1da177e4 LT	186	const struct br_config_bpdu *bpdu)
	187	{
	188	p->designated_root = bpdu->root;
	189	p->designated_cost = bpdu->root_path_cost;
	190	p->designated_bridge = bpdu->bridge_id;
	191	p->designated_port = bpdu->port_id;
	192
9d6f229f	193	mod_timer(&p->message_age_timer, jiffies
1da177e4 LT	194	+ (p->br->max_age - bpdu->message_age));
	195	}
	196
	197	/* called under bridge lock */
9d6f229f	198	static inline void br_record_config_timeout_values(struct net_bridge *br,
1da177e4 LT	199	const struct br_config_bpdu *bpdu)
	200	{
	201	br->max_age = bpdu->max_age;
	202	br->hello_time = bpdu->hello_time;
	203	br->forward_delay = bpdu->forward_delay;
	204	br->topology_change = bpdu->topology_change;
	205	}
	206
	207	/* called under bridge lock */
	208	void br_transmit_tcn(struct net_bridge *br)
	209	{
	210	br_send_tcn_bpdu(br_get_port(br, br->root_port));
	211	}
	212
	213	/* called under bridge lock */
	214	static int br_should_become_designated_port(const struct net_bridge_port *p)
	215	{
	216	struct net_bridge *br;
	217	int t;
	218
	219	br = p->br;
	220	if (br_is_designated_port(p))
	221	return 1;
	222
	223	if (memcmp(&p->designated_root, &br->designated_root, 8))
	224	return 1;
	225
	226	if (br->root_path_cost < p->designated_cost)
	227	return 1;
	228	else if (br->root_path_cost > p->designated_cost)
	229	return 0;
	230
	231	t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
	232	if (t < 0)
	233	return 1;
	234	else if (t > 0)
	235	return 0;
	236
	237	if (p->port_id < p->designated_port)
	238	return 1;
	239
	240	return 0;
	241	}
	242
	243	/* called under bridge lock */
	244	static void br_designated_port_selection(struct net_bridge *br)
	245	{
	246	struct net_bridge_port *p;
	247
	248	list_for_each_entry(p, &br->port_list, list) {
	249	if (p->state != BR_STATE_DISABLED &&
	250	br_should_become_designated_port(p))
	251	br_become_designated_port(p);
	252
	253	}
	254	}
	255
	256	/* called under bridge lock */
	257	static int br_supersedes_port_info(struct net_bridge_port p, struct br_config_bpdu bpdu)
	258	{
	259	int t;
	260
	261	t = memcmp(&bpdu->root, &p->designated_root, 8);
	262	if (t < 0)
263	return 1;
264	else if (t > 0)
265	return 0;
266
267	if (bpdu->root_path_cost < p->designated_cost)
268	return 1;
269	else if (bpdu->root_path_cost > p->designated_cost)
270	return 0;
271
272	t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
273	if (t < 0)
274	return 1;
275	else if (t > 0)
276	return 0;
277
278	if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
279	return 1;
280
281	if (bpdu->port_id <= p->designated_port)
282	return 1;
283
284	return 0;
285	}
286
287	/* called under bridge lock */
288	static inline void br_topology_change_acknowledged(struct net_bridge *br)
289	{
290	br->topology_change_detected = 0;
291	del_timer(&br->tcn_timer);
292	}
293
294	/* called under bridge lock */
295	void br_topology_change_detection(struct net_bridge *br)
296	{
297	int isroot = br_is_root_bridge(br);
298
299	pr_info("%s: topology change detected, %s\n", br->dev->name,
300	isroot ? "propagating" : "sending tcn bpdu");
301
302	if (isroot) {
303	br->topology_change = 1;
304	mod_timer(&br->topology_change_timer, jiffies
305	+ br->bridge_forward_delay + br->bridge_max_age);
306	} else if (!br->topology_change_detected) {
307	br_transmit_tcn(br);
308	mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
309	}
310
311	br->topology_change_detected = 1;
312	}
313
314	/* called under bridge lock */
315	void br_config_bpdu_generation(struct net_bridge *br)
316	{
317	struct net_bridge_port *p;
318
319	list_for_each_entry(p, &br->port_list, list) {
320	if (p->state != BR_STATE_DISABLED &&
321	br_is_designated_port(p))
322	br_transmit_config(p);
323	}
324	}
325
326	/* called under bridge lock */
327	static inline void br_reply(struct net_bridge_port *p)
328	{
329	br_transmit_config(p);
330	}
331
332	/* called under bridge lock */
333	void br_configuration_update(struct net_bridge *br)
334	{
335	br_root_selection(br);
336	br_designated_port_selection(br);
337	}
338
339	/* called under bridge lock */
340	void br_become_designated_port(struct net_bridge_port *p)
341	{
342	struct net_bridge *br;
343
344	br = p->br;
345	p->designated_root = br->designated_root;
346	p->designated_cost = br->root_path_cost;
347	p->designated_bridge = br->bridge_id;
348	p->designated_port = p->port_id;
349	}
350
351
352	/* called under bridge lock */
353	static void br_make_blocking(struct net_bridge_port *p)
354	{
355	if (p->state != BR_STATE_DISABLED &&
356	p->state != BR_STATE_BLOCKING) {
357	if (p->state == BR_STATE_FORWARDING \|\|
358	p->state == BR_STATE_LEARNING)
359	br_topology_change_detection(p->br);
360
361	p->state = BR_STATE_BLOCKING;
362	br_log_state(p);
363	del_timer(&p->forward_delay_timer);
364	}
365	}
366
367	/* called under bridge lock */
368	static void br_make_forwarding(struct net_bridge_port *p)
369	{
370	if (p->state == BR_STATE_BLOCKING) {
9cde0708	371	if (p->br->stp_enabled == BR_KERNEL_STP)
1da177e4	372	p->state = BR_STATE_LISTENING;
9cde0708	373	else
1da177e4	374	p->state = BR_STATE_LEARNING;
9cde0708	375
1da177e4 LT	376	br_log_state(p);
	377	mod_timer(&p->forward_delay_timer, jiffies + p->br->forward_delay); }
	378	}
	379
	380	/* called under bridge lock */
	381	void br_port_state_selection(struct net_bridge *br)
	382	{
	383	struct net_bridge_port *p;
	384
9cde0708 SH	385	/* Don't change port states if userspace is handling STP */
	386	if (br->stp_enabled == BR_USER_STP)
	387	return;
	388
1da177e4 LT	389	list_for_each_entry(p, &br->port_list, list) {
	390	if (p->state != BR_STATE_DISABLED) {
	391	if (p->port_no == br->root_port) {
	392	p->config_pending = 0;
	393	p->topology_change_ack = 0;
	394	br_make_forwarding(p);
	395	} else if (br_is_designated_port(p)) {
	396	del_timer(&p->message_age_timer);
	397	br_make_forwarding(p);
	398	} else {
	399	p->config_pending = 0;
	400	p->topology_change_ack = 0;
	401	br_make_blocking(p);
	402	}
	403	}
	404
	405	}
	406	}
	407
	408	/* called under bridge lock */
	409	static inline void br_topology_change_acknowledge(struct net_bridge_port *p)
	410	{
	411	p->topology_change_ack = 1;
	412	br_transmit_config(p);
	413	}
	414
	415	/* called under bridge lock */
	416	void br_received_config_bpdu(struct net_bridge_port p, struct br_config_bpdu bpdu)
	417	{
	418	struct net_bridge *br;
	419	int was_root;
9d6f229f	420
1da177e4 LT	421	br = p->br;
	422	was_root = br_is_root_bridge(br);
	423
	424	if (br_supersedes_port_info(p, bpdu)) {
	425	br_record_config_information(p, bpdu);
	426	br_configuration_update(br);
	427	br_port_state_selection(br);
	428
	429	if (!br_is_root_bridge(br) && was_root) {
	430	del_timer(&br->hello_timer);
	431	if (br->topology_change_detected) {
	432	del_timer(&br->topology_change_timer);
	433	br_transmit_tcn(br);
	434
9d6f229f	435	mod_timer(&br->tcn_timer,
1da177e4 LT	436	jiffies + br->bridge_hello_time);
	437	}
	438	}
	439
	440	if (p->port_no == br->root_port) {
	441	br_record_config_timeout_values(br, bpdu);
	442	br_config_bpdu_generation(br);
	443	if (bpdu->topology_change_ack)
	444	br_topology_change_acknowledged(br);
	445	}
9d6f229f YH	446	} else if (br_is_designated_port(p)) {
9d6f229f YH	447	br_reply(p);
1da177e4 LT	448	}
	449	}
	450
	451	/* called under bridge lock */
	452	void br_received_tcn_bpdu(struct net_bridge_port *p)
	453	{
	454	if (br_is_designated_port(p)) {
	455	pr_info("%s: received tcn bpdu on port %i(%s)\n",
	456	p->br->dev->name, p->port_no, p->dev->name);
	457
	458	br_topology_change_detection(p->br);
	459	br_topology_change_acknowledge(p);
	460	}
	461	}