[mirror_ubuntu-zesty-kernel.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;
		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);
		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;
9a834b87 SH	212	mod_timer(&p->hold_timer,
9a834b87 SH	213	round_jiffies(jiffies + BR_HOLD_TIME));
1da177e4 LT	214	}
	215	}
	216
	217	/* called under bridge lock */
160d73b8	218	static void br_record_config_information(struct net_bridge_port *p,
160d73b8	219	const struct br_config_bpdu *bpdu)
1da177e4 LT	220	{
	221	p->designated_root = bpdu->root;
	222	p->designated_cost = bpdu->root_path_cost;
	223	p->designated_bridge = bpdu->bridge_id;
	224	p->designated_port = bpdu->port_id;
709e1b5c	225	p->designated_age = jiffies - bpdu->message_age;
1da177e4	226
9d6f229f	227	mod_timer(&p->message_age_timer, jiffies
9a062013	228	+ (bpdu->max_age - bpdu->message_age));
1da177e4 LT	229	}
	230
	231	/* called under bridge lock */
160d73b8	232	static void br_record_config_timeout_values(struct net_bridge *br,
1da177e4 LT	233	const struct br_config_bpdu *bpdu)
	234	{
	235	br->max_age = bpdu->max_age;
	236	br->hello_time = bpdu->hello_time;
	237	br->forward_delay = bpdu->forward_delay;
	238	br->topology_change = bpdu->topology_change;
	239	}
	240
	241	/* called under bridge lock */
	242	void br_transmit_tcn(struct net_bridge *br)
	243	{
91bc033c	244	struct net_bridge_port *p;
	245
	246	p = br_get_port(br, br->root_port);
	247	if (p)
	248	br_send_tcn_bpdu(p);
	249	else
	250	br_notice(br, "root port %u not found for topology notice\n",
	251	br->root_port);
1da177e4 LT	252	}
	253
	254	/* called under bridge lock */
	255	static int br_should_become_designated_port(const struct net_bridge_port *p)
	256	{
	257	struct net_bridge *br;
	258	int t;
	259
	260	br = p->br;
	261	if (br_is_designated_port(p))
	262	return 1;
	263
	264	if (memcmp(&p->designated_root, &br->designated_root, 8))
	265	return 1;
	266
	267	if (br->root_path_cost < p->designated_cost)
	268	return 1;
	269	else if (br->root_path_cost > p->designated_cost)
	270	return 0;
	271
	272	t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
	273	if (t < 0)
	274	return 1;
	275	else if (t > 0)
	276	return 0;
	277
	278	if (p->port_id < p->designated_port)
	279	return 1;
	280
	281	return 0;
	282	}
	283
	284	/* called under bridge lock */
	285	static void br_designated_port_selection(struct net_bridge *br)
	286	{
	287	struct net_bridge_port *p;
	288
	289	list_for_each_entry(p, &br->port_list, list) {
	290	if (p->state != BR_STATE_DISABLED &&
	291	br_should_become_designated_port(p))
	292	br_become_designated_port(p);
	293
	294	}
	295	}
	296
	297	/* called under bridge lock */
160d73b8	298	static int br_supersedes_port_info(const struct net_bridge_port *p,
160d73b8	299	const struct br_config_bpdu *bpdu)
1da177e4 LT	300	{
	301	int t;
	302
	303	t = memcmp(&bpdu->root, &p->designated_root, 8);
	304	if (t < 0)
	305	return 1;
	306	else if (t > 0)
	307	return 0;
	308
	309	if (bpdu->root_path_cost < p->designated_cost)
	310	return 1;
	311	else if (bpdu->root_path_cost > p->designated_cost)
	312	return 0;
	313
	314	t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
	315	if (t < 0)
	316	return 1;
	317	else if (t > 0)
	318	return 0;
	319
	320	if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
	321	return 1;
	322
	323	if (bpdu->port_id <= p->designated_port)
	324	return 1;
	325
	326	return 0;
	327	}
	328
	329	/* called under bridge lock */
160d73b8	330	static void br_topology_change_acknowledged(struct net_bridge *br)
1da177e4 LT	331	{
	332	br->topology_change_detected = 0;
	333	del_timer(&br->tcn_timer);
	334	}
	335
	336	/* called under bridge lock */
	337	void br_topology_change_detection(struct net_bridge *br)
	338	{
	339	int isroot = br_is_root_bridge(br);
	340
4f0611af SH	341	if (br->stp_enabled != BR_KERNEL_STP)
	342	return;
	343
28a16c97	344	br_info(br, "topology change detected, %s\n",
1da177e4 LT	345	isroot ? "propagating" : "sending tcn bpdu");
	346
	347	if (isroot) {
	348	br->topology_change = 1;
	349	mod_timer(&br->topology_change_timer, jiffies
	350	+ br->bridge_forward_delay + br->bridge_max_age);
	351	} else if (!br->topology_change_detected) {
	352	br_transmit_tcn(br);
	353	mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
	354	}
	355
	356	br->topology_change_detected = 1;
	357	}
	358
	359	/* called under bridge lock */
	360	void br_config_bpdu_generation(struct net_bridge *br)
	361	{
	362	struct net_bridge_port *p;
	363
	364	list_for_each_entry(p, &br->port_list, list) {
	365	if (p->state != BR_STATE_DISABLED &&
	366	br_is_designated_port(p))
	367	br_transmit_config(p);
	368	}
	369	}
	370
	371	/* called under bridge lock */
160d73b8	372	static void br_reply(struct net_bridge_port *p)
1da177e4 LT	373	{
	374	br_transmit_config(p);
	375	}
	376
	377	/* called under bridge lock */
	378	void br_configuration_update(struct net_bridge *br)
	379	{
	380	br_root_selection(br);
	381	br_designated_port_selection(br);
	382	}
	383
	384	/* called under bridge lock */
	385	void br_become_designated_port(struct net_bridge_port *p)
	386	{
	387	struct net_bridge *br;
	388
	389	br = p->br;
	390	p->designated_root = br->designated_root;
	391	p->designated_cost = br->root_path_cost;
	392	p->designated_bridge = br->bridge_id;
	393	p->designated_port = p->port_id;
	394	}
	395
	396
	397	/* called under bridge lock */
	398	static void br_make_blocking(struct net_bridge_port *p)
	399	{
	400	if (p->state != BR_STATE_DISABLED &&
	401	p->state != BR_STATE_BLOCKING) {
	402	if (p->state == BR_STATE_FORWARDING \|\|
	403	p->state == BR_STATE_LEARNING)
	404	br_topology_change_detection(p->br);
	405
775dd692	406	br_set_state(p, BR_STATE_BLOCKING);
1da177e4	407	br_log_state(p);
4ecb961c	408	br_ifinfo_notify(RTM_NEWLINK, p);
4ecb961c	409
1da177e4 LT	410	del_timer(&p->forward_delay_timer);
	411	}
	412	}
	413
	414	/* called under bridge lock */
	415	static void br_make_forwarding(struct net_bridge_port *p)
	416	{
ef647f13	417	struct net_bridge *br = p->br;
9cde0708	418
ef647f13 SH	419	if (p->state != BR_STATE_BLOCKING)
	420	return;
	421
a461c029	422	if (br->stp_enabled == BR_NO_STP \|\| br->forward_delay == 0) {
775dd692	423	br_set_state(p, BR_STATE_FORWARDING);
ef647f13 SH	424	br_topology_change_detection(br);
ef647f13 SH	425	del_timer(&p->forward_delay_timer);
160d73b8	426	} else if (br->stp_enabled == BR_KERNEL_STP)
775dd692	427	br_set_state(p, BR_STATE_LISTENING);
ef647f13	428	else
775dd692	429	br_set_state(p, BR_STATE_LEARNING);
ef647f13 SH	430
ef647f13 SH	431	br_log_state(p);
4ecb961c	432	br_ifinfo_notify(RTM_NEWLINK, p);
ef647f13 SH	433
	434	if (br->forward_delay != 0)
	435	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
1da177e4 LT	436	}
	437
	438	/* called under bridge lock */
	439	void br_port_state_selection(struct net_bridge *br)
	440	{
	441	struct net_bridge_port *p;
1faa4356	442	unsigned int liveports = 0;
1da177e4 LT	443
1da177e4 LT	444	list_for_each_entry(p, &br->port_list, list) {
1faa4356	445	if (p->state == BR_STATE_DISABLED)
	446	continue;
	447
b03b6dd5 VD	448	/* Don't change port states if userspace is handling STP */
	449	if (br->stp_enabled != BR_USER_STP) {
	450	if (p->port_no == br->root_port) {
	451	p->config_pending = 0;
	452	p->topology_change_ack = 0;
	453	br_make_forwarding(p);
	454	} else if (br_is_designated_port(p)) {
	455	del_timer(&p->message_age_timer);
	456	br_make_forwarding(p);
	457	} else {
	458	p->config_pending = 0;
	459	p->topology_change_ack = 0;
	460	br_make_blocking(p);
	461	}
1da177e4 LT	462	}
1da177e4 LT	463
7ce42de1 NA	464	if (p->state != BR_STATE_BLOCKING)
7ce42de1 NA	465	br_multicast_enable_port(p);
1faa4356	466	if (p->state == BR_STATE_FORWARDING)
1faa4356	467	++liveports;
1da177e4	468	}
1faa4356	469
	470	if (liveports == 0)
	471	netif_carrier_off(br->dev);
	472	else
	473	netif_carrier_on(br->dev);
1da177e4 LT	474	}
	475
	476	/* called under bridge lock */
160d73b8	477	static void br_topology_change_acknowledge(struct net_bridge_port *p)
1da177e4 LT	478	{
	479	p->topology_change_ack = 1;
	480	br_transmit_config(p);
	481	}
	482
	483	/* called under bridge lock */
160d73b8	484	void br_received_config_bpdu(struct net_bridge_port *p,
160d73b8	485	const struct br_config_bpdu *bpdu)
1da177e4 LT	486	{
	487	struct net_bridge *br;
	488	int was_root;
9d6f229f	489
1da177e4 LT	490	br = p->br;
	491	was_root = br_is_root_bridge(br);
	492
	493	if (br_supersedes_port_info(p, bpdu)) {
	494	br_record_config_information(p, bpdu);
	495	br_configuration_update(br);
	496	br_port_state_selection(br);
	497
	498	if (!br_is_root_bridge(br) && was_root) {
	499	del_timer(&br->hello_timer);
	500	if (br->topology_change_detected) {
	501	del_timer(&br->topology_change_timer);
	502	br_transmit_tcn(br);
	503
9d6f229f	504	mod_timer(&br->tcn_timer,
1da177e4 LT	505	jiffies + br->bridge_hello_time);
	506	}
	507	}
	508
	509	if (p->port_no == br->root_port) {
	510	br_record_config_timeout_values(br, bpdu);
	511	br_config_bpdu_generation(br);
	512	if (bpdu->topology_change_ack)
	513	br_topology_change_acknowledged(br);
	514	}
9d6f229f YH	515	} else if (br_is_designated_port(p)) {
9d6f229f YH	516	br_reply(p);
1da177e4 LT	517	}
	518	}
	519
	520	/* called under bridge lock */
	521	void br_received_tcn_bpdu(struct net_bridge_port *p)
	522	{
	523	if (br_is_designated_port(p)) {
28a16c97	524	br_info(p->br, "port %u(%s) received tcn bpdu\n",
95c96174	525	(unsigned int) p->port_no, p->dev->name);
1da177e4 LT	526
	527	br_topology_change_detection(p->br);
	528	br_topology_change_acknowledge(p);
	529	}
	530	}
14f98f25	531
	532	/* Change bridge STP parameter */
	533	int br_set_hello_time(struct net_bridge *br, unsigned long val)
	534	{
	535	unsigned long t = clock_t_to_jiffies(val);
	536
	537	if (t < BR_MIN_HELLO_TIME \|\| t > BR_MAX_HELLO_TIME)
	538	return -ERANGE;
	539
	540	spin_lock_bh(&br->lock);
	541	br->bridge_hello_time = t;
	542	if (br_is_root_bridge(br))
	543	br->hello_time = br->bridge_hello_time;
	544	spin_unlock_bh(&br->lock);
	545	return 0;
	546	}
	547
	548	int br_set_max_age(struct net_bridge *br, unsigned long val)
	549	{
	550	unsigned long t = clock_t_to_jiffies(val);
	551
	552	if (t < BR_MIN_MAX_AGE \|\| t > BR_MAX_MAX_AGE)
	553	return -ERANGE;
	554
	555	spin_lock_bh(&br->lock);
	556	br->bridge_max_age = t;
	557	if (br_is_root_bridge(br))
	558	br->max_age = br->bridge_max_age;
	559	spin_unlock_bh(&br->lock);
	560	return 0;
	561
	562	}
	563
be4f154d HX	564	void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
	565	{
	566	br->bridge_forward_delay = t;
	567	if (br_is_root_bridge(br))
	568	br->forward_delay = br->bridge_forward_delay;
	569	}
	570
14f98f25	571	int br_set_forward_delay(struct net_bridge *br, unsigned long val)
	572	{
	573	unsigned long t = clock_t_to_jiffies(val);
be4f154d	574	int err = -ERANGE;
14f98f25	575
be4f154d	576	spin_lock_bh(&br->lock);
14f98f25	577	if (br->stp_enabled != BR_NO_STP &&
14f98f25	578	(t < BR_MIN_FORWARD_DELAY \|\| t > BR_MAX_FORWARD_DELAY))
be4f154d	579	goto unlock;
14f98f25	580
be4f154d HX	581	__br_set_forward_delay(br, t);
	582	err = 0;
	583
	584	unlock:
14f98f25	585	spin_unlock_bh(&br->lock);
be4f154d	586	return err;
14f98f25	587	}