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

/*
 *	Spanning tree protocol; generic parts
 *	Linux ethernet bridge
 *
 *	Authors:
 *	Lennert Buytenhek		<[email protected]>
 *
 *	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/rculist.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 *const 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);

	if (br->stp_enabled != BR_KERNEL_STP)
		return;

	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)
{
	struct net_bridge *br = p->br;

	if (p->state != BR_STATE_BLOCKING)
		return;

	if (br->forward_delay == 0) {
		p->state = BR_STATE_FORWARDING;
		br_topology_change_detection(br);
		del_timer(&p->forward_delay_timer);
	}
	else if (p->br->stp_enabled == BR_KERNEL_STP)
		p->state = BR_STATE_LISTENING;
	else
		p->state = BR_STATE_LEARNING;

	br_log_state(p);

	if (br->forward_delay != 0)
		mod_timer(&p->forward_delay_timer, jiffies + 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 <[email protected]>
	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>
82524746	14	#include <linux/rculist.h>
1da177e4 LT	15
	16	#include "br_private.h"
	17	#include "br_private_stp.h"
	18
	19	/* since time values in bpdu are in jiffies and then scaled (1/256)
	20	* before sending, make sure that is at least one.
	21	*/
	22	#define MESSAGE_AGE_INCR ((HZ < 256) ? 1 : (HZ/256))
	23
36cbd3dc	24	static const char *const br_port_state_names[] = {
9d6f229f	25	[BR_STATE_DISABLED] = "disabled",
1da177e4	26	[BR_STATE_LISTENING] = "listening",
9d6f229f YH	27	[BR_STATE_LEARNING] = "learning",
9d6f229f YH	28	[BR_STATE_FORWARDING] = "forwarding",
1da177e4 LT	29	[BR_STATE_BLOCKING] = "blocking",
	30	};
	31
	32	void br_log_state(const struct net_bridge_port *p)
	33	{
	34	pr_info("%s: port %d(%s) entering %s state\n",
9d6f229f	35	p->br->dev->name, p->port_no, p->dev->name,
1da177e4 LT	36	br_port_state_names[p->state]);
	37
	38	}
	39
	40	/* called under bridge lock */
	41	struct net_bridge_port br_get_port(struct net_bridge br, u16 port_no)
	42	{
	43	struct net_bridge_port *p;
	44
	45	list_for_each_entry_rcu(p, &br->port_list, list) {
	46	if (p->port_no == port_no)
	47	return p;
	48	}
	49
	50	return NULL;
	51	}
	52
	53	/* called under bridge lock */
9d6f229f	54	static int br_should_become_root_port(const struct net_bridge_port *p,
1da177e4 LT	55	u16 root_port)
	56	{
	57	struct net_bridge *br;
	58	struct net_bridge_port *rp;
	59	int t;
	60
	61	br = p->br;
	62	if (p->state == BR_STATE_DISABLED \|\|
	63	br_is_designated_port(p))
	64	return 0;
	65
	66	if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
	67	return 0;
	68
	69	if (!root_port)
	70	return 1;
	71
	72	rp = br_get_port(br, root_port);
	73
	74	t = memcmp(&p->designated_root, &rp->designated_root, 8);
	75	if (t < 0)
	76	return 1;
	77	else if (t > 0)
	78	return 0;
	79
	80	if (p->designated_cost + p->path_cost <
	81	rp->designated_cost + rp->path_cost)
	82	return 1;
	83	else if (p->designated_cost + p->path_cost >
	84	rp->designated_cost + rp->path_cost)
	85	return 0;
	86
	87	t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
	88	if (t < 0)
	89	return 1;
	90	else if (t > 0)
	91	return 0;
	92
	93	if (p->designated_port < rp->designated_port)
	94	return 1;
	95	else if (p->designated_port > rp->designated_port)
	96	return 0;
	97
	98	if (p->port_id < rp->port_id)
	99	return 1;
	100
	101	return 0;
	102	}
	103
	104	/* called under bridge lock */
	105	static void br_root_selection(struct net_bridge *br)
	106	{
	107	struct net_bridge_port *p;
	108	u16 root_port = 0;
	109
	110	list_for_each_entry(p, &br->port_list, list) {
	111	if (br_should_become_root_port(p, root_port))
	112	root_port = p->port_no;
	113
	114	}
	115
	116	br->root_port = root_port;
	117
	118	if (!root_port) {
119	br->designated_root = br->bridge_id;
120	br->root_path_cost = 0;
121	} else {
122	p = br_get_port(br, root_port);
123	br->designated_root = p->designated_root;
124	br->root_path_cost = p->designated_cost + p->path_cost;
125	}
126	}
127
128	/* called under bridge lock */
129	void br_become_root_bridge(struct net_bridge *br)
130	{
131	br->max_age = br->bridge_max_age;
132	br->hello_time = br->bridge_hello_time;
133	br->forward_delay = br->bridge_forward_delay;
134	br_topology_change_detection(br);
135	del_timer(&br->tcn_timer);
136
137	if (br->dev->flags & IFF_UP) {
138	br_config_bpdu_generation(br);
139	mod_timer(&br->hello_timer, jiffies + br->hello_time);
140	}
141	}
142
143	/* called under bridge lock */
144	void br_transmit_config(struct net_bridge_port *p)
145	{
146	struct br_config_bpdu bpdu;
147	struct net_bridge *br;
148
149
150	if (timer_pending(&p->hold_timer)) {
151	p->config_pending = 1;
152	return;
153	}
154
155	br = p->br;
156
157	bpdu.topology_change = br->topology_change;
158	bpdu.topology_change_ack = p->topology_change_ack;
159	bpdu.root = br->designated_root;
160	bpdu.root_path_cost = br->root_path_cost;
161	bpdu.bridge_id = br->bridge_id;
162	bpdu.port_id = p->port_id;
163	if (br_is_root_bridge(br))
164	bpdu.message_age = 0;
165	else {
166	struct net_bridge_port *root
167	= br_get_port(br, br->root_port);
168	bpdu.message_age = br->max_age
169	- (root->message_age_timer.expires - jiffies)
170	+ MESSAGE_AGE_INCR;
171	}
172	bpdu.max_age = br->max_age;
173	bpdu.hello_time = br->hello_time;
174	bpdu.forward_delay = br->forward_delay;
175
176	if (bpdu.message_age < br->max_age) {
177	br_send_config_bpdu(p, &bpdu);
178	p->topology_change_ack = 0;
179	p->config_pending = 0;
9a834b87 SH	180	mod_timer(&p->hold_timer,
9a834b87 SH	181	round_jiffies(jiffies + BR_HOLD_TIME));
1da177e4 LT	182	}
	183	}
	184
	185	/* called under bridge lock */
9d6f229f	186	static inline void br_record_config_information(struct net_bridge_port *p,
1da177e4 LT	187	const struct br_config_bpdu *bpdu)
	188	{
	189	p->designated_root = bpdu->root;
	190	p->designated_cost = bpdu->root_path_cost;
	191	p->designated_bridge = bpdu->bridge_id;
	192	p->designated_port = bpdu->port_id;
	193
9d6f229f	194	mod_timer(&p->message_age_timer, jiffies
1da177e4 LT	195	+ (p->br->max_age - bpdu->message_age));
	196	}
	197
	198	/* called under bridge lock */
9d6f229f	199	static inline void br_record_config_timeout_values(struct net_bridge *br,
1da177e4 LT	200	const struct br_config_bpdu *bpdu)
	201	{
	202	br->max_age = bpdu->max_age;
	203	br->hello_time = bpdu->hello_time;
	204	br->forward_delay = bpdu->forward_delay;
	205	br->topology_change = bpdu->topology_change;
	206	}
	207
	208	/* called under bridge lock */
	209	void br_transmit_tcn(struct net_bridge *br)
	210	{
	211	br_send_tcn_bpdu(br_get_port(br, br->root_port));
	212	}
	213
	214	/* called under bridge lock */
	215	static int br_should_become_designated_port(const struct net_bridge_port *p)
	216	{
	217	struct net_bridge *br;
	218	int t;
	219
	220	br = p->br;
	221	if (br_is_designated_port(p))
	222	return 1;
	223
	224	if (memcmp(&p->designated_root, &br->designated_root, 8))
	225	return 1;
	226
	227	if (br->root_path_cost < p->designated_cost)
	228	return 1;
	229	else if (br->root_path_cost > p->designated_cost)
	230	return 0;
	231
	232	t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
	233	if (t < 0)
	234	return 1;
	235	else if (t > 0)
	236	return 0;
	237
	238	if (p->port_id < p->designated_port)
	239	return 1;
	240
	241	return 0;
	242	}
	243
	244	/* called under bridge lock */
	245	static void br_designated_port_selection(struct net_bridge *br)
	246	{
	247	struct net_bridge_port *p;
	248
	249	list_for_each_entry(p, &br->port_list, list) {
	250	if (p->state != BR_STATE_DISABLED &&
	251	br_should_become_designated_port(p))
	252	br_become_designated_port(p);
	253
	254	}
	255	}
	256
	257	/* called under bridge lock */
	258	static int br_supersedes_port_info(struct net_bridge_port p, struct br_config_bpdu bpdu)
	259	{
	260	int t;
	261
	262	t = memcmp(&bpdu->root, &p->designated_root, 8);
	263	if (t < 0)
264	return 1;
265	else if (t > 0)
266	return 0;
267
268	if (bpdu->root_path_cost < p->designated_cost)
269	return 1;
270	else if (bpdu->root_path_cost > p->designated_cost)
271	return 0;
272
273	t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
274	if (t < 0)
275	return 1;
276	else if (t > 0)
277	return 0;
278
279	if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
280	return 1;
281
282	if (bpdu->port_id <= p->designated_port)
283	return 1;
284
285	return 0;
286	}
287
288	/* called under bridge lock */
289	static inline void br_topology_change_acknowledged(struct net_bridge *br)
290	{
291	br->topology_change_detected = 0;
292	del_timer(&br->tcn_timer);
293	}
294
295	/* called under bridge lock */
296	void br_topology_change_detection(struct net_bridge *br)
297	{
298	int isroot = br_is_root_bridge(br);
299
4f0611af SH	300	if (br->stp_enabled != BR_KERNEL_STP)
	301	return;
	302
1da177e4 LT	303	pr_info("%s: topology change detected, %s\n", br->dev->name,
	304	isroot ? "propagating" : "sending tcn bpdu");
	305
	306	if (isroot) {
	307	br->topology_change = 1;
	308	mod_timer(&br->topology_change_timer, jiffies
	309	+ br->bridge_forward_delay + br->bridge_max_age);
	310	} else if (!br->topology_change_detected) {
	311	br_transmit_tcn(br);
	312	mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
	313	}
	314
	315	br->topology_change_detected = 1;
	316	}
	317
	318	/* called under bridge lock */
	319	void br_config_bpdu_generation(struct net_bridge *br)
	320	{
	321	struct net_bridge_port *p;
	322
	323	list_for_each_entry(p, &br->port_list, list) {
	324	if (p->state != BR_STATE_DISABLED &&
	325	br_is_designated_port(p))
	326	br_transmit_config(p);
	327	}
	328	}
	329
	330	/* called under bridge lock */
	331	static inline void br_reply(struct net_bridge_port *p)
	332	{
	333	br_transmit_config(p);
	334	}
	335
	336	/* called under bridge lock */
	337	void br_configuration_update(struct net_bridge *br)
	338	{
	339	br_root_selection(br);
	340	br_designated_port_selection(br);
	341	}
	342
	343	/* called under bridge lock */
	344	void br_become_designated_port(struct net_bridge_port *p)
	345	{
	346	struct net_bridge *br;
	347
	348	br = p->br;
	349	p->designated_root = br->designated_root;
	350	p->designated_cost = br->root_path_cost;
	351	p->designated_bridge = br->bridge_id;
	352	p->designated_port = p->port_id;
	353	}
	354
	355
	356	/* called under bridge lock */
	357	static void br_make_blocking(struct net_bridge_port *p)
	358	{
	359	if (p->state != BR_STATE_DISABLED &&
	360	p->state != BR_STATE_BLOCKING) {
	361	if (p->state == BR_STATE_FORWARDING \|\|
	362	p->state == BR_STATE_LEARNING)
	363	br_topology_change_detection(p->br);
	364
	365	p->state = BR_STATE_BLOCKING;
	366	br_log_state(p);
367	del_timer(&p->forward_delay_timer);
368	}
369	}
370
371	/* called under bridge lock */
372	static void br_make_forwarding(struct net_bridge_port *p)
373	{
ef647f13	374	struct net_bridge *br = p->br;
9cde0708	375
ef647f13 SH	376	if (p->state != BR_STATE_BLOCKING)
	377	return;
	378
	379	if (br->forward_delay == 0) {
	380	p->state = BR_STATE_FORWARDING;
	381	br_topology_change_detection(br);
	382	del_timer(&p->forward_delay_timer);
	383	}
	384	else if (p->br->stp_enabled == BR_KERNEL_STP)
	385	p->state = BR_STATE_LISTENING;
	386	else
	387	p->state = BR_STATE_LEARNING;
	388
	389	br_log_state(p);
	390
	391	if (br->forward_delay != 0)
	392	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
1da177e4 LT	393	}
	394
	395	/* called under bridge lock */
	396	void br_port_state_selection(struct net_bridge *br)
	397	{
	398	struct net_bridge_port *p;
	399
9cde0708 SH	400	/* Don't change port states if userspace is handling STP */
	401	if (br->stp_enabled == BR_USER_STP)
	402	return;
	403
1da177e4 LT	404	list_for_each_entry(p, &br->port_list, list) {
	405	if (p->state != BR_STATE_DISABLED) {
	406	if (p->port_no == br->root_port) {
	407	p->config_pending = 0;
	408	p->topology_change_ack = 0;
	409	br_make_forwarding(p);
	410	} else if (br_is_designated_port(p)) {
	411	del_timer(&p->message_age_timer);
	412	br_make_forwarding(p);
	413	} else {
	414	p->config_pending = 0;
	415	p->topology_change_ack = 0;
	416	br_make_blocking(p);
	417	}
	418	}
	419
	420	}
	421	}
	422
	423	/* called under bridge lock */
	424	static inline void br_topology_change_acknowledge(struct net_bridge_port *p)
	425	{
	426	p->topology_change_ack = 1;
	427	br_transmit_config(p);
	428	}
	429
	430	/* called under bridge lock */
	431	void br_received_config_bpdu(struct net_bridge_port p, struct br_config_bpdu bpdu)
	432	{
	433	struct net_bridge *br;
	434	int was_root;
9d6f229f	435
1da177e4 LT	436	br = p->br;
	437	was_root = br_is_root_bridge(br);
	438
	439	if (br_supersedes_port_info(p, bpdu)) {
	440	br_record_config_information(p, bpdu);
	441	br_configuration_update(br);
	442	br_port_state_selection(br);
	443
	444	if (!br_is_root_bridge(br) && was_root) {
	445	del_timer(&br->hello_timer);
	446	if (br->topology_change_detected) {
	447	del_timer(&br->topology_change_timer);
	448	br_transmit_tcn(br);
	449
9d6f229f	450	mod_timer(&br->tcn_timer,
1da177e4 LT	451	jiffies + br->bridge_hello_time);
	452	}
	453	}
	454
	455	if (p->port_no == br->root_port) {
	456	br_record_config_timeout_values(br, bpdu);
	457	br_config_bpdu_generation(br);
	458	if (bpdu->topology_change_ack)
	459	br_topology_change_acknowledged(br);
	460	}
9d6f229f YH	461	} else if (br_is_designated_port(p)) {
9d6f229f YH	462	br_reply(p);
1da177e4 LT	463	}
	464	}
	465
	466	/* called under bridge lock */
	467	void br_received_tcn_bpdu(struct net_bridge_port *p)
	468	{
	469	if (br_is_designated_port(p)) {
	470	pr_info("%s: received tcn bpdu on port %i(%s)\n",
	471	p->br->dev->name, p->port_no, p->dev->name);
	472
	473	br_topology_change_detection(p->br);
	474	br_topology_change_acknowledge(p);
	475	}
	476	}