[GitHub/mt8127/android_kernel_alcatel_ttab.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 <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 STP tick.
 */
#define MESSAGE_AGE_INCR	((HZ / 256) + 1)

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)
{
	br_info(p->br, "port %u(%s) entered %s state\n",
		(unsigned) 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 = (jiffies - root->designated_age)
			+ 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 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;
	p->designated_age = jiffies - bpdu->message_age;

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

/* called under bridge lock */
static 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(const struct net_bridge_port *p,
				   const 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 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;

	br_info(br, "topology change detected, %s\n",
		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 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);
		br_ifinfo_notify(RTM_NEWLINK, 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->stp_enabled == BR_NO_STP || br->forward_delay == 0) {
		p->state = BR_STATE_FORWARDING;
		br_topology_change_detection(br);
		del_timer(&p->forward_delay_timer);
	} else if (br->stp_enabled == BR_KERNEL_STP)
		p->state = BR_STATE_LISTENING;
	else
		p->state = BR_STATE_LEARNING;

	br_multicast_enable_port(p);
	br_log_state(p);
	br_ifinfo_notify(RTM_NEWLINK, 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;
	unsigned int liveports = 0;

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

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

		if (p->state == BR_STATE_FORWARDING)
			++liveports;
	}

	if (liveports == 0)
		netif_carrier_off(br->dev);
	else
		netif_carrier_on(br->dev);
}

/* called under bridge lock */
static 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,
			     const 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)) {
		br_info(p->br, "port %u(%s) received tcn bpdu\n",
			(unsigned) p->port_no, p->dev->name);

		br_topology_change_detection(p->br);
		br_topology_change_acknowledge(p);
	}
}

/* Change bridge STP parameter */
int br_set_hello_time(struct net_bridge *br, unsigned long val)
{
	unsigned long t = clock_t_to_jiffies(val);

	if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
		return -ERANGE;

	spin_lock_bh(&br->lock);
	br->bridge_hello_time = t;
	if (br_is_root_bridge(br))
		br->hello_time = br->bridge_hello_time;
	spin_unlock_bh(&br->lock);
	return 0;
}

int br_set_max_age(struct net_bridge *br, unsigned long val)
{
	unsigned long t = clock_t_to_jiffies(val);

	if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
		return -ERANGE;

	spin_lock_bh(&br->lock);
	br->bridge_max_age = t;
	if (br_is_root_bridge(br))
		br->max_age = br->bridge_max_age;
	spin_unlock_bh(&br->lock);
	return 0;

}

int br_set_forward_delay(struct net_bridge *br, unsigned long val)
{
	unsigned long t = clock_t_to_jiffies(val);

	if (br->stp_enabled != BR_NO_STP &&
	    (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
		return -ERANGE;

	spin_lock_bh(&br->lock);
	br->bridge_forward_delay = t;
	if (br_is_root_bridge(br))
		br->forward_delay = br->bridge_forward_delay;
	spin_unlock_bh(&br->lock);
	return 0;
}
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>
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)
aaca735f	20	* before sending, make sure that is at least one STP tick.
1da177e4	21	*/
aaca735f	22	#define MESSAGE_AGE_INCR ((HZ / 256) + 1)
1da177e4	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	{
d9e179ec	34	br_info(p->br, "port %u(%s) entered %s state\n",
28a16c97	35	(unsigned) p->port_no, p->dev->name,
1da177e4	36	br_port_state_names[p->state]);
1da177e4 LT	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;
1da177e4 LT	112	}
	113
	114	br->root_port = root_port;
	115
	116	if (!root_port) {
	117	br->designated_root = br->bridge_id;
	118	br->root_path_cost = 0;
	119	} else {
	120	p = br_get_port(br, root_port);
	121	br->designated_root = p->designated_root;
	122	br->root_path_cost = p->designated_cost + p->path_cost;
	123	}
	124	}
	125
	126	/* called under bridge lock */
	127	void br_become_root_bridge(struct net_bridge *br)
	128	{
	129	br->max_age = br->bridge_max_age;
	130	br->hello_time = br->bridge_hello_time;
	131	br->forward_delay = br->bridge_forward_delay;
	132	br_topology_change_detection(br);
	133	del_timer(&br->tcn_timer);
	134
	135	if (br->dev->flags & IFF_UP) {
	136	br_config_bpdu_generation(br);
	137	mod_timer(&br->hello_timer, jiffies + br->hello_time);
	138	}
	139	}
	140
	141	/* called under bridge lock */
	142	void br_transmit_config(struct net_bridge_port *p)
	143	{
	144	struct br_config_bpdu bpdu;
	145	struct net_bridge *br;
	146
1da177e4 LT	147	if (timer_pending(&p->hold_timer)) {
	148	p->config_pending = 1;
	149	return;
	150	}
	151
	152	br = p->br;
	153
	154	bpdu.topology_change = br->topology_change;
	155	bpdu.topology_change_ack = p->topology_change_ack;
	156	bpdu.root = br->designated_root;
	157	bpdu.root_path_cost = br->root_path_cost;
	158	bpdu.bridge_id = br->bridge_id;
	159	bpdu.port_id = p->port_id;
	160	if (br_is_root_bridge(br))
	161	bpdu.message_age = 0;
	162	else {
	163	struct net_bridge_port *root
	164	= br_get_port(br, br->root_port);
0c03150e	165	bpdu.message_age = (jiffies - root->designated_age)
1da177e4 LT	166	+ MESSAGE_AGE_INCR;
	167	}
	168	bpdu.max_age = br->max_age;
	169	bpdu.hello_time = br->hello_time;
	170	bpdu.forward_delay = br->forward_delay;
	171
	172	if (bpdu.message_age < br->max_age) {
	173	br_send_config_bpdu(p, &bpdu);
	174	p->topology_change_ack = 0;
	175	p->config_pending = 0;
9a834b87 SH	176	mod_timer(&p->hold_timer,
9a834b87 SH	177	round_jiffies(jiffies + BR_HOLD_TIME));
1da177e4 LT	178	}
	179	}
	180
	181	/* called under bridge lock */
160d73b8	182	static void br_record_config_information(struct net_bridge_port *p,
160d73b8	183	const struct br_config_bpdu *bpdu)
1da177e4 LT	184	{
	185	p->designated_root = bpdu->root;
	186	p->designated_cost = bpdu->root_path_cost;
	187	p->designated_bridge = bpdu->bridge_id;
	188	p->designated_port = bpdu->port_id;
709e1b5c	189	p->designated_age = jiffies - bpdu->message_age;
1da177e4	190
9d6f229f	191	mod_timer(&p->message_age_timer, jiffies
1da177e4 LT	192	+ (p->br->max_age - bpdu->message_age));
	193	}
	194
	195	/* called under bridge lock */
160d73b8	196	static void br_record_config_timeout_values(struct net_bridge *br,
1da177e4 LT	197	const struct br_config_bpdu *bpdu)
	198	{
	199	br->max_age = bpdu->max_age;
	200	br->hello_time = bpdu->hello_time;
	201	br->forward_delay = bpdu->forward_delay;
	202	br->topology_change = bpdu->topology_change;
	203	}
	204
	205	/* called under bridge lock */
	206	void br_transmit_tcn(struct net_bridge *br)
	207	{
	208	br_send_tcn_bpdu(br_get_port(br, br->root_port));
	209	}
	210
	211	/* called under bridge lock */
	212	static int br_should_become_designated_port(const struct net_bridge_port *p)
	213	{
	214	struct net_bridge *br;
	215	int t;
	216
	217	br = p->br;
	218	if (br_is_designated_port(p))
	219	return 1;
	220
	221	if (memcmp(&p->designated_root, &br->designated_root, 8))
	222	return 1;
	223
	224	if (br->root_path_cost < p->designated_cost)
	225	return 1;
	226	else if (br->root_path_cost > p->designated_cost)
	227	return 0;
	228
	229	t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
	230	if (t < 0)
	231	return 1;
	232	else if (t > 0)
	233	return 0;
	234
	235	if (p->port_id < p->designated_port)
	236	return 1;
	237
	238	return 0;
	239	}
	240
	241	/* called under bridge lock */
	242	static void br_designated_port_selection(struct net_bridge *br)
	243	{
	244	struct net_bridge_port *p;
	245
	246	list_for_each_entry(p, &br->port_list, list) {
	247	if (p->state != BR_STATE_DISABLED &&
	248	br_should_become_designated_port(p))
	249	br_become_designated_port(p);
	250
	251	}
	252	}
	253
	254	/* called under bridge lock */
160d73b8	255	static int br_supersedes_port_info(const struct net_bridge_port *p,
160d73b8	256	const struct br_config_bpdu *bpdu)
1da177e4 LT	257	{
	258	int t;
	259
	260	t = memcmp(&bpdu->root, &p->designated_root, 8);
	261	if (t < 0)
	262	return 1;
	263	else if (t > 0)
	264	return 0;
	265
	266	if (bpdu->root_path_cost < p->designated_cost)
	267	return 1;
	268	else if (bpdu->root_path_cost > p->designated_cost)
	269	return 0;
	270
	271	t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
	272	if (t < 0)
	273	return 1;
	274	else if (t > 0)
	275	return 0;
	276
	277	if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
	278	return 1;
	279
	280	if (bpdu->port_id <= p->designated_port)
	281	return 1;
	282
	283	return 0;
	284	}
	285
	286	/* called under bridge lock */
160d73b8	287	static void br_topology_change_acknowledged(struct net_bridge *br)
1da177e4 LT	288	{
	289	br->topology_change_detected = 0;
	290	del_timer(&br->tcn_timer);
	291	}
	292
	293	/* called under bridge lock */
	294	void br_topology_change_detection(struct net_bridge *br)
	295	{
	296	int isroot = br_is_root_bridge(br);
	297
4f0611af SH	298	if (br->stp_enabled != BR_KERNEL_STP)
	299	return;
	300
28a16c97	301	br_info(br, "topology change detected, %s\n",
1da177e4 LT	302	isroot ? "propagating" : "sending tcn bpdu");
	303
	304	if (isroot) {
	305	br->topology_change = 1;
	306	mod_timer(&br->topology_change_timer, jiffies
	307	+ br->bridge_forward_delay + br->bridge_max_age);
	308	} else if (!br->topology_change_detected) {
	309	br_transmit_tcn(br);
	310	mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
	311	}
	312
	313	br->topology_change_detected = 1;
	314	}
	315
	316	/* called under bridge lock */
	317	void br_config_bpdu_generation(struct net_bridge *br)
	318	{
	319	struct net_bridge_port *p;
	320
	321	list_for_each_entry(p, &br->port_list, list) {
	322	if (p->state != BR_STATE_DISABLED &&
	323	br_is_designated_port(p))
	324	br_transmit_config(p);
	325	}
	326	}
	327
	328	/* called under bridge lock */
160d73b8	329	static void br_reply(struct net_bridge_port *p)
1da177e4 LT	330	{
	331	br_transmit_config(p);
	332	}
	333
	334	/* called under bridge lock */
	335	void br_configuration_update(struct net_bridge *br)
	336	{
	337	br_root_selection(br);
	338	br_designated_port_selection(br);
	339	}
	340
	341	/* called under bridge lock */
	342	void br_become_designated_port(struct net_bridge_port *p)
	343	{
	344	struct net_bridge *br;
	345
	346	br = p->br;
	347	p->designated_root = br->designated_root;
	348	p->designated_cost = br->root_path_cost;
	349	p->designated_bridge = br->bridge_id;
	350	p->designated_port = p->port_id;
	351	}
	352
	353
	354	/* called under bridge lock */
	355	static void br_make_blocking(struct net_bridge_port *p)
	356	{
	357	if (p->state != BR_STATE_DISABLED &&
	358	p->state != BR_STATE_BLOCKING) {
	359	if (p->state == BR_STATE_FORWARDING \|\|
	360	p->state == BR_STATE_LEARNING)
	361	br_topology_change_detection(p->br);
	362
	363	p->state = BR_STATE_BLOCKING;
	364	br_log_state(p);
4ecb961c	365	br_ifinfo_notify(RTM_NEWLINK, p);
4ecb961c	366
1da177e4 LT	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
a461c029	379	if (br->stp_enabled == BR_NO_STP \|\| br->forward_delay == 0) {
ef647f13 SH	380	p->state = BR_STATE_FORWARDING;
	381	br_topology_change_detection(br);
	382	del_timer(&p->forward_delay_timer);
160d73b8	383	} else if (br->stp_enabled == BR_KERNEL_STP)
ef647f13 SH	384	p->state = BR_STATE_LISTENING;
	385	else
	386	p->state = BR_STATE_LEARNING;
	387
3fe2d7c7	388	br_multicast_enable_port(p);
ef647f13	389	br_log_state(p);
4ecb961c	390	br_ifinfo_notify(RTM_NEWLINK, p);
ef647f13 SH	391
	392	if (br->forward_delay != 0)
	393	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
1da177e4 LT	394	}
	395
	396	/* called under bridge lock */
	397	void br_port_state_selection(struct net_bridge *br)
	398	{
	399	struct net_bridge_port *p;
1faa4356	400	unsigned int liveports = 0;
1da177e4 LT	401
1da177e4 LT	402	list_for_each_entry(p, &br->port_list, list) {
1faa4356	403	if (p->state == BR_STATE_DISABLED)
	404	continue;
	405
b03b6dd5 VD	406	/* Don't change port states if userspace is handling STP */
	407	if (br->stp_enabled != BR_USER_STP) {
	408	if (p->port_no == br->root_port) {
	409	p->config_pending = 0;
	410	p->topology_change_ack = 0;
	411	br_make_forwarding(p);
	412	} else if (br_is_designated_port(p)) {
	413	del_timer(&p->message_age_timer);
	414	br_make_forwarding(p);
	415	} else {
	416	p->config_pending = 0;
	417	p->topology_change_ack = 0;
	418	br_make_blocking(p);
	419	}
1da177e4 LT	420	}
1da177e4 LT	421
1faa4356	422	if (p->state == BR_STATE_FORWARDING)
1faa4356	423	++liveports;
1da177e4	424	}
1faa4356	425
	426	if (liveports == 0)
	427	netif_carrier_off(br->dev);
	428	else
	429	netif_carrier_on(br->dev);
1da177e4 LT	430	}
	431
	432	/* called under bridge lock */
160d73b8	433	static void br_topology_change_acknowledge(struct net_bridge_port *p)
1da177e4 LT	434	{
	435	p->topology_change_ack = 1;
	436	br_transmit_config(p);
	437	}
	438
	439	/* called under bridge lock */
160d73b8	440	void br_received_config_bpdu(struct net_bridge_port *p,
160d73b8	441	const struct br_config_bpdu *bpdu)
1da177e4 LT	442	{
	443	struct net_bridge *br;
	444	int was_root;
9d6f229f	445
1da177e4 LT	446	br = p->br;
	447	was_root = br_is_root_bridge(br);
	448
	449	if (br_supersedes_port_info(p, bpdu)) {
	450	br_record_config_information(p, bpdu);
	451	br_configuration_update(br);
	452	br_port_state_selection(br);
	453
	454	if (!br_is_root_bridge(br) && was_root) {
	455	del_timer(&br->hello_timer);
	456	if (br->topology_change_detected) {
	457	del_timer(&br->topology_change_timer);
	458	br_transmit_tcn(br);
	459
9d6f229f	460	mod_timer(&br->tcn_timer,
1da177e4 LT	461	jiffies + br->bridge_hello_time);
	462	}
	463	}
	464
	465	if (p->port_no == br->root_port) {
	466	br_record_config_timeout_values(br, bpdu);
	467	br_config_bpdu_generation(br);
	468	if (bpdu->topology_change_ack)
	469	br_topology_change_acknowledged(br);
	470	}
9d6f229f YH	471	} else if (br_is_designated_port(p)) {
9d6f229f YH	472	br_reply(p);
1da177e4 LT	473	}
	474	}
	475
	476	/* called under bridge lock */
	477	void br_received_tcn_bpdu(struct net_bridge_port *p)
	478	{
	479	if (br_is_designated_port(p)) {
28a16c97	480	br_info(p->br, "port %u(%s) received tcn bpdu\n",
28a16c97	481	(unsigned) p->port_no, p->dev->name);
1da177e4 LT	482
	483	br_topology_change_detection(p->br);
	484	br_topology_change_acknowledge(p);
	485	}
	486	}
14f98f25	487
	488	/* Change bridge STP parameter */
	489	int br_set_hello_time(struct net_bridge *br, unsigned long val)
	490	{
	491	unsigned long t = clock_t_to_jiffies(val);
	492
	493	if (t < BR_MIN_HELLO_TIME \|\| t > BR_MAX_HELLO_TIME)
	494	return -ERANGE;
	495
	496	spin_lock_bh(&br->lock);
	497	br->bridge_hello_time = t;
	498	if (br_is_root_bridge(br))
	499	br->hello_time = br->bridge_hello_time;
	500	spin_unlock_bh(&br->lock);
	501	return 0;
	502	}
	503
	504	int br_set_max_age(struct net_bridge *br, unsigned long val)
	505	{
	506	unsigned long t = clock_t_to_jiffies(val);
	507
	508	if (t < BR_MIN_MAX_AGE \|\| t > BR_MAX_MAX_AGE)
	509	return -ERANGE;
	510
	511	spin_lock_bh(&br->lock);
	512	br->bridge_max_age = t;
	513	if (br_is_root_bridge(br))
	514	br->max_age = br->bridge_max_age;
	515	spin_unlock_bh(&br->lock);
	516	return 0;
	517
	518	}
	519
	520	int br_set_forward_delay(struct net_bridge *br, unsigned long val)
	521	{
	522	unsigned long t = clock_t_to_jiffies(val);
	523
	524	if (br->stp_enabled != BR_NO_STP &&
	525	(t < BR_MIN_FORWARD_DELAY \|\| t > BR_MAX_FORWARD_DELAY))
	526	return -ERANGE;
	527
	528	spin_lock_bh(&br->lock);
	529	br->bridge_forward_delay = t;
	530	if (br_is_root_bridge(br))
	531	br->forward_delay = br->bridge_forward_delay;
	532	spin_unlock_bh(&br->lock);
	533	return 0;
	534	}