[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 <linux/rculist.h>
#include <net/switchdev.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 int) p->port_no, p->dev->name,
		br_port_state_names[p->state]);
}

void br_set_state(struct net_bridge_port *p, unsigned int state)
{
	struct switchdev_attr attr = {
		.id = SWITCHDEV_ATTR_PORT_STP_STATE,
		.u.stp_state = state,
	};
	int err;

	p->state = state;
	err = switchdev_port_attr_set(p->dev, &attr);
	if (err && err != -EOPNOTSUPP)
		br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
				(unsigned int) p->port_no, p->dev->name);
}

/* 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;
}

static void br_root_port_block(const struct net_bridge *br,
			       struct net_bridge_port *p)
{

	br_notice(br, "port %u(%s) tried to become root port (blocked)",
		  (unsigned int) p->port_no, p->dev->name);

	br_set_state(p, BR_STATE_LISTENING);
	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 */
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))
			continue;

		if (p->flags & BR_ROOT_BLOCK)
			br_root_port_block(br, p);
		else
			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;
		if (p->br->stp_enabled == BR_KERNEL_STP)
			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
		  + (bpdu->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)
{
	struct net_bridge_port *p;

	p = br_get_port(br, br->root_port);
	if (p)
		br_send_tcn_bpdu(p);
	else
		br_notice(br, "root port %u not found for topology notice\n",
			  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);

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

	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_BLOCKING)
			br_multicast_enable_port(p);
		/* Multicast is not disabled for the port when it goes in
		 * blocking state because the timers will expire and stop by
		 * themselves without sending more queries.
		 */
		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 int) 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;

}

void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
{
	br->bridge_forward_delay = t;
	if (br_is_root_bridge(br))
		br->forward_delay = br->bridge_forward_delay;
}

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

	spin_lock_bh(&br->lock);
	if (br->stp_enabled != BR_NO_STP &&
	    (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
		goto unlock;

	__br_set_forward_delay(br, t);
	err = 0;

unlock:
	spin_unlock_bh(&br->lock);
	return err;
}
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>
38dcf357	15	#include <net/switchdev.h>
1da177e4 LT	16
	17	#include "br_private.h"
	18	#include "br_private_stp.h"
	19
	20	/* since time values in bpdu are in jiffies and then scaled (1/256)
aaca735f	21	* before sending, make sure that is at least one STP tick.
1da177e4	22	*/
aaca735f	23	#define MESSAGE_AGE_INCR ((HZ / 256) + 1)
1da177e4	24
36cbd3dc	25	static const char *const br_port_state_names[] = {
9d6f229f	26	[BR_STATE_DISABLED] = "disabled",
1da177e4	27	[BR_STATE_LISTENING] = "listening",
9d6f229f YH	28	[BR_STATE_LEARNING] = "learning",
9d6f229f YH	29	[BR_STATE_FORWARDING] = "forwarding",
1da177e4 LT	30	[BR_STATE_BLOCKING] = "blocking",
	31	};
	32
	33	void br_log_state(const struct net_bridge_port *p)
	34	{
d9e179ec	35	br_info(p->br, "port %u(%s) entered %s state\n",
95c96174	36	(unsigned int) p->port_no, p->dev->name,
1da177e4	37	br_port_state_names[p->state]);
1da177e4 LT	38	}
1da177e4 LT	39
775dd692 FF	40	void br_set_state(struct net_bridge_port *p, unsigned int state)
775dd692 FF	41	{
35636062 SF	42	struct switchdev_attr attr = {
35636062 SF	43	.id = SWITCHDEV_ATTR_PORT_STP_STATE,
42275bd8	44	.u.stp_state = state,
35636062	45	};
38dcf357 SF	46	int err;
38dcf357 SF	47
775dd692	48	p->state = state;
35636062	49	err = switchdev_port_attr_set(p->dev, &attr);
38dcf357 SF	50	if (err && err != -EOPNOTSUPP)
	51	br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
	52	(unsigned int) p->port_no, p->dev->name);
775dd692 FF	53	}
775dd692 FF	54
1da177e4 LT	55	/* called under bridge lock */
	56	struct net_bridge_port br_get_port(struct net_bridge br, u16 port_no)
	57	{
	58	struct net_bridge_port *p;
	59
	60	list_for_each_entry_rcu(p, &br->port_list, list) {
	61	if (p->port_no == port_no)
	62	return p;
	63	}
	64
	65	return NULL;
	66	}
	67
	68	/* called under bridge lock */
9d6f229f	69	static int br_should_become_root_port(const struct net_bridge_port *p,
1da177e4 LT	70	u16 root_port)
	71	{
	72	struct net_bridge *br;
	73	struct net_bridge_port *rp;
	74	int t;
	75
	76	br = p->br;
	77	if (p->state == BR_STATE_DISABLED \|\|
	78	br_is_designated_port(p))
	79	return 0;
	80
	81	if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
	82	return 0;
	83
	84	if (!root_port)
	85	return 1;
	86
	87	rp = br_get_port(br, root_port);
	88
	89	t = memcmp(&p->designated_root, &rp->designated_root, 8);
	90	if (t < 0)
	91	return 1;
	92	else if (t > 0)
	93	return 0;
	94
	95	if (p->designated_cost + p->path_cost <
	96	rp->designated_cost + rp->path_cost)
	97	return 1;
	98	else if (p->designated_cost + p->path_cost >
	99	rp->designated_cost + rp->path_cost)
	100	return 0;
	101
	102	t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
	103	if (t < 0)
	104	return 1;
	105	else if (t > 0)
	106	return 0;
	107
	108	if (p->designated_port < rp->designated_port)
	109	return 1;
	110	else if (p->designated_port > rp->designated_port)
	111	return 0;
	112
	113	if (p->port_id < rp->port_id)
	114	return 1;
	115
	116	return 0;
	117	}
	118
1007dd1a	119	static void br_root_port_block(const struct net_bridge *br,
	120	struct net_bridge_port *p)
	121	{
	122
	123	br_notice(br, "port %u(%s) tried to become root port (blocked)",
	124	(unsigned int) p->port_no, p->dev->name);
	125
775dd692	126	br_set_state(p, BR_STATE_LISTENING);
1007dd1a	127	br_log_state(p);
	128	br_ifinfo_notify(RTM_NEWLINK, p);
	129
	130	if (br->forward_delay > 0)
	131	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
	132	}
	133
1da177e4 LT	134	/* called under bridge lock */
	135	static void br_root_selection(struct net_bridge *br)
	136	{
	137	struct net_bridge_port *p;
	138	u16 root_port = 0;
	139
	140	list_for_each_entry(p, &br->port_list, list) {
1007dd1a	141	if (!br_should_become_root_port(p, root_port))
	142	continue;
	143
	144	if (p->flags & BR_ROOT_BLOCK)
	145	br_root_port_block(br, p);
	146	else
1da177e4	147	root_port = p->port_no;
1da177e4 LT	148	}
	149
	150	br->root_port = root_port;
	151
	152	if (!root_port) {
	153	br->designated_root = br->bridge_id;
	154	br->root_path_cost = 0;
	155	} else {
	156	p = br_get_port(br, root_port);
	157	br->designated_root = p->designated_root;
	158	br->root_path_cost = p->designated_cost + p->path_cost;
	159	}
	160	}
	161
	162	/* called under bridge lock */
	163	void br_become_root_bridge(struct net_bridge *br)
	164	{
	165	br->max_age = br->bridge_max_age;
	166	br->hello_time = br->bridge_hello_time;
	167	br->forward_delay = br->bridge_forward_delay;
	168	br_topology_change_detection(br);
	169	del_timer(&br->tcn_timer);
	170
	171	if (br->dev->flags & IFF_UP) {
	172	br_config_bpdu_generation(br);
	173	mod_timer(&br->hello_timer, jiffies + br->hello_time);
	174	}
	175	}
	176
	177	/* called under bridge lock */
	178	void br_transmit_config(struct net_bridge_port *p)
	179	{
	180	struct br_config_bpdu bpdu;
	181	struct net_bridge *br;
	182
1da177e4 LT	183	if (timer_pending(&p->hold_timer)) {
	184	p->config_pending = 1;
	185	return;
	186	}
	187
	188	br = p->br;
	189
	190	bpdu.topology_change = br->topology_change;
	191	bpdu.topology_change_ack = p->topology_change_ack;
	192	bpdu.root = br->designated_root;
	193	bpdu.root_path_cost = br->root_path_cost;
	194	bpdu.bridge_id = br->bridge_id;
	195	bpdu.port_id = p->port_id;
	196	if (br_is_root_bridge(br))
	197	bpdu.message_age = 0;
	198	else {
	199	struct net_bridge_port *root
	200	= br_get_port(br, br->root_port);
0c03150e	201	bpdu.message_age = (jiffies - root->designated_age)
1da177e4 LT	202	+ MESSAGE_AGE_INCR;
	203	}
	204	bpdu.max_age = br->max_age;
	205	bpdu.hello_time = br->hello_time;
	206	bpdu.forward_delay = br->forward_delay;
	207
	208	if (bpdu.message_age < br->max_age) {
	209	br_send_config_bpdu(p, &bpdu);
	210	p->topology_change_ack = 0;
	211	p->config_pending = 0;
76b91c32 NA	212	if (p->br->stp_enabled == BR_KERNEL_STP)
	213	mod_timer(&p->hold_timer,
	214	round_jiffies(jiffies + BR_HOLD_TIME));
1da177e4 LT	215	}
	216	}
	217
	218	/* called under bridge lock */
160d73b8	219	static void br_record_config_information(struct net_bridge_port *p,
160d73b8	220	const struct br_config_bpdu *bpdu)
1da177e4 LT	221	{
	222	p->designated_root = bpdu->root;
	223	p->designated_cost = bpdu->root_path_cost;
	224	p->designated_bridge = bpdu->bridge_id;
	225	p->designated_port = bpdu->port_id;
709e1b5c	226	p->designated_age = jiffies - bpdu->message_age;
1da177e4	227
9d6f229f	228	mod_timer(&p->message_age_timer, jiffies
9a062013	229	+ (bpdu->max_age - bpdu->message_age));
1da177e4 LT	230	}
	231
	232	/* called under bridge lock */
160d73b8	233	static void br_record_config_timeout_values(struct net_bridge *br,
1da177e4 LT	234	const struct br_config_bpdu *bpdu)
	235	{
	236	br->max_age = bpdu->max_age;
	237	br->hello_time = bpdu->hello_time;
	238	br->forward_delay = bpdu->forward_delay;
	239	br->topology_change = bpdu->topology_change;
	240	}
	241
	242	/* called under bridge lock */
	243	void br_transmit_tcn(struct net_bridge *br)
	244	{
91bc033c	245	struct net_bridge_port *p;
	246
	247	p = br_get_port(br, br->root_port);
	248	if (p)
	249	br_send_tcn_bpdu(p);
	250	else
	251	br_notice(br, "root port %u not found for topology notice\n",
	252	br->root_port);
1da177e4 LT	253	}
	254
	255	/* called under bridge lock */
	256	static int br_should_become_designated_port(const struct net_bridge_port *p)
	257	{
	258	struct net_bridge *br;
	259	int t;
	260
	261	br = p->br;
	262	if (br_is_designated_port(p))
	263	return 1;
	264
	265	if (memcmp(&p->designated_root, &br->designated_root, 8))
	266	return 1;
	267
	268	if (br->root_path_cost < p->designated_cost)
	269	return 1;
	270	else if (br->root_path_cost > p->designated_cost)
	271	return 0;
	272
	273	t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
	274	if (t < 0)
	275	return 1;
	276	else if (t > 0)
	277	return 0;
	278
	279	if (p->port_id < p->designated_port)
	280	return 1;
	281
	282	return 0;
	283	}
	284
	285	/* called under bridge lock */
	286	static void br_designated_port_selection(struct net_bridge *br)
	287	{
	288	struct net_bridge_port *p;
	289
	290	list_for_each_entry(p, &br->port_list, list) {
	291	if (p->state != BR_STATE_DISABLED &&
	292	br_should_become_designated_port(p))
	293	br_become_designated_port(p);
	294
	295	}
	296	}
	297
	298	/* called under bridge lock */
160d73b8	299	static int br_supersedes_port_info(const struct net_bridge_port *p,
160d73b8	300	const struct br_config_bpdu *bpdu)
1da177e4 LT	301	{
	302	int t;
	303
	304	t = memcmp(&bpdu->root, &p->designated_root, 8);
	305	if (t < 0)
	306	return 1;
	307	else if (t > 0)
	308	return 0;
	309
	310	if (bpdu->root_path_cost < p->designated_cost)
	311	return 1;
	312	else if (bpdu->root_path_cost > p->designated_cost)
	313	return 0;
	314
	315	t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
	316	if (t < 0)
	317	return 1;
	318	else if (t > 0)
	319	return 0;
	320
	321	if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
	322	return 1;
	323
	324	if (bpdu->port_id <= p->designated_port)
	325	return 1;
	326
	327	return 0;
	328	}
	329
	330	/* called under bridge lock */
160d73b8	331	static void br_topology_change_acknowledged(struct net_bridge *br)
1da177e4 LT	332	{
	333	br->topology_change_detected = 0;
	334	del_timer(&br->tcn_timer);
	335	}
	336
	337	/* called under bridge lock */
	338	void br_topology_change_detection(struct net_bridge *br)
	339	{
	340	int isroot = br_is_root_bridge(br);
	341
4f0611af SH	342	if (br->stp_enabled != BR_KERNEL_STP)
	343	return;
	344
28a16c97	345	br_info(br, "topology change detected, %s\n",
1da177e4 LT	346	isroot ? "propagating" : "sending tcn bpdu");
	347
	348	if (isroot) {
	349	br->topology_change = 1;
	350	mod_timer(&br->topology_change_timer, jiffies
	351	+ br->bridge_forward_delay + br->bridge_max_age);
	352	} else if (!br->topology_change_detected) {
	353	br_transmit_tcn(br);
	354	mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
	355	}
	356
	357	br->topology_change_detected = 1;
	358	}
	359
	360	/* called under bridge lock */
	361	void br_config_bpdu_generation(struct net_bridge *br)
	362	{
	363	struct net_bridge_port *p;
	364
	365	list_for_each_entry(p, &br->port_list, list) {
	366	if (p->state != BR_STATE_DISABLED &&
	367	br_is_designated_port(p))
	368	br_transmit_config(p);
	369	}
	370	}
	371
	372	/* called under bridge lock */
160d73b8	373	static void br_reply(struct net_bridge_port *p)
1da177e4 LT	374	{
	375	br_transmit_config(p);
	376	}
	377
	378	/* called under bridge lock */
	379	void br_configuration_update(struct net_bridge *br)
	380	{
	381	br_root_selection(br);
	382	br_designated_port_selection(br);
	383	}
	384
	385	/* called under bridge lock */
	386	void br_become_designated_port(struct net_bridge_port *p)
	387	{
	388	struct net_bridge *br;
	389
	390	br = p->br;
	391	p->designated_root = br->designated_root;
	392	p->designated_cost = br->root_path_cost;
	393	p->designated_bridge = br->bridge_id;
	394	p->designated_port = p->port_id;
	395	}
	396
	397
	398	/* called under bridge lock */
	399	static void br_make_blocking(struct net_bridge_port *p)
	400	{
	401	if (p->state != BR_STATE_DISABLED &&
	402	p->state != BR_STATE_BLOCKING) {
	403	if (p->state == BR_STATE_FORWARDING \|\|
	404	p->state == BR_STATE_LEARNING)
	405	br_topology_change_detection(p->br);
	406
775dd692	407	br_set_state(p, BR_STATE_BLOCKING);
1da177e4	408	br_log_state(p);
4ecb961c	409	br_ifinfo_notify(RTM_NEWLINK, p);
4ecb961c	410
1da177e4 LT	411	del_timer(&p->forward_delay_timer);
	412	}
	413	}
	414
	415	/* called under bridge lock */
	416	static void br_make_forwarding(struct net_bridge_port *p)
	417	{
ef647f13	418	struct net_bridge *br = p->br;
9cde0708	419
ef647f13 SH	420	if (p->state != BR_STATE_BLOCKING)
	421	return;
	422
a461c029	423	if (br->stp_enabled == BR_NO_STP \|\| br->forward_delay == 0) {
775dd692	424	br_set_state(p, BR_STATE_FORWARDING);
ef647f13 SH	425	br_topology_change_detection(br);
ef647f13 SH	426	del_timer(&p->forward_delay_timer);
160d73b8	427	} else if (br->stp_enabled == BR_KERNEL_STP)
775dd692	428	br_set_state(p, BR_STATE_LISTENING);
ef647f13	429	else
775dd692	430	br_set_state(p, BR_STATE_LEARNING);
ef647f13 SH	431
ef647f13 SH	432	br_log_state(p);
4ecb961c	433	br_ifinfo_notify(RTM_NEWLINK, p);
ef647f13 SH	434
	435	if (br->forward_delay != 0)
	436	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
1da177e4 LT	437	}
	438
	439	/* called under bridge lock */
	440	void br_port_state_selection(struct net_bridge *br)
	441	{
	442	struct net_bridge_port *p;
1faa4356	443	unsigned int liveports = 0;
1da177e4 LT	444
1da177e4 LT	445	list_for_each_entry(p, &br->port_list, list) {
1faa4356	446	if (p->state == BR_STATE_DISABLED)
	447	continue;
	448
b03b6dd5 VD	449	/* Don't change port states if userspace is handling STP */
	450	if (br->stp_enabled != BR_USER_STP) {
	451	if (p->port_no == br->root_port) {
	452	p->config_pending = 0;
	453	p->topology_change_ack = 0;
	454	br_make_forwarding(p);
	455	} else if (br_is_designated_port(p)) {
	456	del_timer(&p->message_age_timer);
	457	br_make_forwarding(p);
	458	} else {
	459	p->config_pending = 0;
	460	p->topology_change_ack = 0;
	461	br_make_blocking(p);
	462	}
1da177e4 LT	463	}
1da177e4 LT	464
7ce42de1 NA	465	if (p->state != BR_STATE_BLOCKING)
7ce42de1 NA	466	br_multicast_enable_port(p);
9aa66382 NA	467	/* Multicast is not disabled for the port when it goes in
	468	* blocking state because the timers will expire and stop by
	469	* themselves without sending more queries.
	470	*/
1faa4356	471	if (p->state == BR_STATE_FORWARDING)
1faa4356	472	++liveports;
1da177e4	473	}
1faa4356	474
	475	if (liveports == 0)
	476	netif_carrier_off(br->dev);
	477	else
	478	netif_carrier_on(br->dev);
1da177e4 LT	479	}
	480
	481	/* called under bridge lock */
160d73b8	482	static void br_topology_change_acknowledge(struct net_bridge_port *p)
1da177e4 LT	483	{
	484	p->topology_change_ack = 1;
	485	br_transmit_config(p);
	486	}
	487
	488	/* called under bridge lock */
160d73b8	489	void br_received_config_bpdu(struct net_bridge_port *p,
160d73b8	490	const struct br_config_bpdu *bpdu)
1da177e4 LT	491	{
	492	struct net_bridge *br;
	493	int was_root;
9d6f229f	494
1da177e4 LT	495	br = p->br;
	496	was_root = br_is_root_bridge(br);
	497
	498	if (br_supersedes_port_info(p, bpdu)) {
	499	br_record_config_information(p, bpdu);
	500	br_configuration_update(br);
	501	br_port_state_selection(br);
	502
	503	if (!br_is_root_bridge(br) && was_root) {
	504	del_timer(&br->hello_timer);
	505	if (br->topology_change_detected) {
	506	del_timer(&br->topology_change_timer);
	507	br_transmit_tcn(br);
	508
9d6f229f	509	mod_timer(&br->tcn_timer,
1da177e4 LT	510	jiffies + br->bridge_hello_time);
	511	}
	512	}
	513
	514	if (p->port_no == br->root_port) {
	515	br_record_config_timeout_values(br, bpdu);
	516	br_config_bpdu_generation(br);
	517	if (bpdu->topology_change_ack)
	518	br_topology_change_acknowledged(br);
	519	}
9d6f229f YH	520	} else if (br_is_designated_port(p)) {
9d6f229f YH	521	br_reply(p);
1da177e4 LT	522	}
	523	}
	524
	525	/* called under bridge lock */
	526	void br_received_tcn_bpdu(struct net_bridge_port *p)
	527	{
	528	if (br_is_designated_port(p)) {
28a16c97	529	br_info(p->br, "port %u(%s) received tcn bpdu\n",
95c96174	530	(unsigned int) p->port_no, p->dev->name);
1da177e4 LT	531
	532	br_topology_change_detection(p->br);
	533	br_topology_change_acknowledge(p);
	534	}
	535	}
14f98f25	536
	537	/* Change bridge STP parameter */
	538	int br_set_hello_time(struct net_bridge *br, unsigned long val)
	539	{
	540	unsigned long t = clock_t_to_jiffies(val);
	541
	542	if (t < BR_MIN_HELLO_TIME \|\| t > BR_MAX_HELLO_TIME)
	543	return -ERANGE;
	544
	545	spin_lock_bh(&br->lock);
	546	br->bridge_hello_time = t;
	547	if (br_is_root_bridge(br))
	548	br->hello_time = br->bridge_hello_time;
	549	spin_unlock_bh(&br->lock);
	550	return 0;
	551	}
	552
	553	int br_set_max_age(struct net_bridge *br, unsigned long val)
	554	{
	555	unsigned long t = clock_t_to_jiffies(val);
	556
	557	if (t < BR_MIN_MAX_AGE \|\| t > BR_MAX_MAX_AGE)
	558	return -ERANGE;
	559
	560	spin_lock_bh(&br->lock);
	561	br->bridge_max_age = t;
	562	if (br_is_root_bridge(br))
	563	br->max_age = br->bridge_max_age;
	564	spin_unlock_bh(&br->lock);
	565	return 0;
	566
	567	}
	568
be4f154d HX	569	void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
	570	{
	571	br->bridge_forward_delay = t;
	572	if (br_is_root_bridge(br))
	573	br->forward_delay = br->bridge_forward_delay;
	574	}
	575
14f98f25	576	int br_set_forward_delay(struct net_bridge *br, unsigned long val)
	577	{
	578	unsigned long t = clock_t_to_jiffies(val);
be4f154d	579	int err = -ERANGE;
14f98f25	580
be4f154d	581	spin_lock_bh(&br->lock);
14f98f25	582	if (br->stp_enabled != BR_NO_STP &&
14f98f25	583	(t < BR_MIN_FORWARD_DELAY \|\| t > BR_MAX_FORWARD_DELAY))
be4f154d	584	goto unlock;
14f98f25	585
be4f154d HX	586	__br_set_forward_delay(br, t);
	587	err = 0;
	588
	589	unlock:
14f98f25	590	spin_unlock_bh(&br->lock);
be4f154d	591	return err;
14f98f25	592	}