[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 <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_ID_PORT_STP_STATE,
		.flags = SWITCHDEV_F_DEFER,
		.u.stp_state = state,
	};
	int err;

	p->state = state;
	err = switchdev_port_attr_set(p->dev, &attr);
	if (err)
		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;

}

int br_set_ageing_time(struct net_bridge *br, u32 ageing_time)
{
	struct switchdev_attr attr = {
		.id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
		.flags = SWITCHDEV_F_SKIP_EOPNOTSUPP,
		.u.ageing_time = ageing_time,
	};
	unsigned long t = clock_t_to_jiffies(ageing_time);
	int err;

	if (t < BR_MIN_AGEING_TIME || t > BR_MAX_AGEING_TIME)
		return -ERANGE;

	err = switchdev_port_attr_set(br->dev, &attr);
	if (err)
		return err;

	br->ageing_time = t;
	mod_timer(&br->gc_timer, jiffies);

	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 <[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>
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	42	struct switchdev_attr attr = {
1f868398	43	.id = SWITCHDEV_ATTR_ID_PORT_STP_STATE,
0bc05d58	44	.flags = SWITCHDEV_F_DEFER,
42275bd8	45	.u.stp_state = state,
35636062	46	};
38dcf357 SF	47	int err;
38dcf357 SF	48
775dd692	49	p->state = state;
35636062	50	err = switchdev_port_attr_set(p->dev, &attr);
0bc05d58	51	if (err)
38dcf357 SF	52	br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
38dcf357 SF	53	(unsigned int) p->port_no, p->dev->name);
775dd692 FF	54	}
775dd692 FF	55
1da177e4 LT	56	/* called under bridge lock */
	57	struct net_bridge_port br_get_port(struct net_bridge br, u16 port_no)
	58	{
	59	struct net_bridge_port *p;
	60
	61	list_for_each_entry_rcu(p, &br->port_list, list) {
	62	if (p->port_no == port_no)
	63	return p;
	64	}
	65
	66	return NULL;
	67	}
	68
	69	/* called under bridge lock */
9d6f229f	70	static int br_should_become_root_port(const struct net_bridge_port *p,
1da177e4 LT	71	u16 root_port)
	72	{
	73	struct net_bridge *br;
	74	struct net_bridge_port *rp;
	75	int t;
	76
	77	br = p->br;
	78	if (p->state == BR_STATE_DISABLED \|\|
	79	br_is_designated_port(p))
	80	return 0;
	81
	82	if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
	83	return 0;
	84
	85	if (!root_port)
	86	return 1;
	87
	88	rp = br_get_port(br, root_port);
	89
	90	t = memcmp(&p->designated_root, &rp->designated_root, 8);
	91	if (t < 0)
	92	return 1;
	93	else if (t > 0)
	94	return 0;
	95
	96	if (p->designated_cost + p->path_cost <
	97	rp->designated_cost + rp->path_cost)
	98	return 1;
	99	else if (p->designated_cost + p->path_cost >
	100	rp->designated_cost + rp->path_cost)
	101	return 0;
	102
	103	t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
	104	if (t < 0)
	105	return 1;
	106	else if (t > 0)
	107	return 0;
	108
	109	if (p->designated_port < rp->designated_port)
	110	return 1;
	111	else if (p->designated_port > rp->designated_port)
	112	return 0;
	113
	114	if (p->port_id < rp->port_id)
	115	return 1;
	116
	117	return 0;
	118	}
	119
1007dd1a	120	static void br_root_port_block(const struct net_bridge *br,
	121	struct net_bridge_port *p)
	122	{
	123
	124	br_notice(br, "port %u(%s) tried to become root port (blocked)",
	125	(unsigned int) p->port_no, p->dev->name);
	126
775dd692	127	br_set_state(p, BR_STATE_LISTENING);
1007dd1a	128	br_log_state(p);
	129	br_ifinfo_notify(RTM_NEWLINK, p);
	130
	131	if (br->forward_delay > 0)
	132	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
	133	}
	134
1da177e4 LT	135	/* called under bridge lock */
	136	static void br_root_selection(struct net_bridge *br)
	137	{
	138	struct net_bridge_port *p;
	139	u16 root_port = 0;
	140
	141	list_for_each_entry(p, &br->port_list, list) {
1007dd1a	142	if (!br_should_become_root_port(p, root_port))
	143	continue;
	144
	145	if (p->flags & BR_ROOT_BLOCK)
	146	br_root_port_block(br, p);
	147	else
1da177e4	148	root_port = p->port_no;
1da177e4 LT	149	}
	150
	151	br->root_port = root_port;
	152
	153	if (!root_port) {
	154	br->designated_root = br->bridge_id;
	155	br->root_path_cost = 0;
	156	} else {
	157	p = br_get_port(br, root_port);
	158	br->designated_root = p->designated_root;
	159	br->root_path_cost = p->designated_cost + p->path_cost;
	160	}
	161	}
	162
	163	/* called under bridge lock */
	164	void br_become_root_bridge(struct net_bridge *br)
	165	{
	166	br->max_age = br->bridge_max_age;
	167	br->hello_time = br->bridge_hello_time;
	168	br->forward_delay = br->bridge_forward_delay;
	169	br_topology_change_detection(br);
	170	del_timer(&br->tcn_timer);
	171
	172	if (br->dev->flags & IFF_UP) {
	173	br_config_bpdu_generation(br);
	174	mod_timer(&br->hello_timer, jiffies + br->hello_time);
	175	}
	176	}
	177
	178	/* called under bridge lock */
	179	void br_transmit_config(struct net_bridge_port *p)
	180	{
	181	struct br_config_bpdu bpdu;
	182	struct net_bridge *br;
	183
1da177e4 LT	184	if (timer_pending(&p->hold_timer)) {
	185	p->config_pending = 1;
	186	return;
	187	}
	188
	189	br = p->br;
	190
	191	bpdu.topology_change = br->topology_change;
	192	bpdu.topology_change_ack = p->topology_change_ack;
	193	bpdu.root = br->designated_root;
	194	bpdu.root_path_cost = br->root_path_cost;
	195	bpdu.bridge_id = br->bridge_id;
	196	bpdu.port_id = p->port_id;
	197	if (br_is_root_bridge(br))
	198	bpdu.message_age = 0;
	199	else {
	200	struct net_bridge_port *root
	201	= br_get_port(br, br->root_port);
0c03150e	202	bpdu.message_age = (jiffies - root->designated_age)
1da177e4 LT	203	+ MESSAGE_AGE_INCR;
	204	}
	205	bpdu.max_age = br->max_age;
	206	bpdu.hello_time = br->hello_time;
	207	bpdu.forward_delay = br->forward_delay;
	208
	209	if (bpdu.message_age < br->max_age) {
	210	br_send_config_bpdu(p, &bpdu);
	211	p->topology_change_ack = 0;
	212	p->config_pending = 0;
76b91c32 NA	213	if (p->br->stp_enabled == BR_KERNEL_STP)
	214	mod_timer(&p->hold_timer,
	215	round_jiffies(jiffies + BR_HOLD_TIME));
1da177e4 LT	216	}
	217	}
	218
	219	/* called under bridge lock */
160d73b8	220	static void br_record_config_information(struct net_bridge_port *p,
160d73b8	221	const struct br_config_bpdu *bpdu)
1da177e4 LT	222	{
	223	p->designated_root = bpdu->root;
	224	p->designated_cost = bpdu->root_path_cost;
	225	p->designated_bridge = bpdu->bridge_id;
	226	p->designated_port = bpdu->port_id;
709e1b5c	227	p->designated_age = jiffies - bpdu->message_age;
1da177e4	228
9d6f229f	229	mod_timer(&p->message_age_timer, jiffies
9a062013	230	+ (bpdu->max_age - bpdu->message_age));
1da177e4 LT	231	}
	232
	233	/* called under bridge lock */
160d73b8	234	static void br_record_config_timeout_values(struct net_bridge *br,
1da177e4 LT	235	const struct br_config_bpdu *bpdu)
	236	{
	237	br->max_age = bpdu->max_age;
	238	br->hello_time = bpdu->hello_time;
	239	br->forward_delay = bpdu->forward_delay;
	240	br->topology_change = bpdu->topology_change;
	241	}
	242
	243	/* called under bridge lock */
	244	void br_transmit_tcn(struct net_bridge *br)
	245	{
91bc033c	246	struct net_bridge_port *p;
	247
	248	p = br_get_port(br, br->root_port);
	249	if (p)
	250	br_send_tcn_bpdu(p);
	251	else
	252	br_notice(br, "root port %u not found for topology notice\n",
	253	br->root_port);
1da177e4 LT	254	}
	255
	256	/* called under bridge lock */
	257	static int br_should_become_designated_port(const struct net_bridge_port *p)
	258	{
	259	struct net_bridge *br;
	260	int t;
	261
	262	br = p->br;
	263	if (br_is_designated_port(p))
	264	return 1;
	265
	266	if (memcmp(&p->designated_root, &br->designated_root, 8))
	267	return 1;
	268
	269	if (br->root_path_cost < p->designated_cost)
	270	return 1;
	271	else if (br->root_path_cost > p->designated_cost)
	272	return 0;
	273
	274	t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
	275	if (t < 0)
	276	return 1;
	277	else if (t > 0)
	278	return 0;
	279
	280	if (p->port_id < p->designated_port)
	281	return 1;
	282
	283	return 0;
	284	}
	285
	286	/* called under bridge lock */
	287	static void br_designated_port_selection(struct net_bridge *br)
	288	{
	289	struct net_bridge_port *p;
	290
	291	list_for_each_entry(p, &br->port_list, list) {
	292	if (p->state != BR_STATE_DISABLED &&
	293	br_should_become_designated_port(p))
	294	br_become_designated_port(p);
	295
	296	}
	297	}
	298
	299	/* called under bridge lock */
160d73b8	300	static int br_supersedes_port_info(const struct net_bridge_port *p,
160d73b8	301	const struct br_config_bpdu *bpdu)
1da177e4 LT	302	{
	303	int t;
	304
	305	t = memcmp(&bpdu->root, &p->designated_root, 8);
	306	if (t < 0)
	307	return 1;
	308	else if (t > 0)
	309	return 0;
	310
	311	if (bpdu->root_path_cost < p->designated_cost)
	312	return 1;
	313	else if (bpdu->root_path_cost > p->designated_cost)
	314	return 0;
	315
	316	t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
	317	if (t < 0)
	318	return 1;
	319	else if (t > 0)
	320	return 0;
	321
	322	if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
	323	return 1;
	324
	325	if (bpdu->port_id <= p->designated_port)
	326	return 1;
	327
	328	return 0;
	329	}
	330
	331	/* called under bridge lock */
160d73b8	332	static void br_topology_change_acknowledged(struct net_bridge *br)
1da177e4 LT	333	{
	334	br->topology_change_detected = 0;
	335	del_timer(&br->tcn_timer);
	336	}
	337
	338	/* called under bridge lock */
	339	void br_topology_change_detection(struct net_bridge *br)
	340	{
	341	int isroot = br_is_root_bridge(br);
	342
4f0611af SH	343	if (br->stp_enabled != BR_KERNEL_STP)
	344	return;
	345
28a16c97	346	br_info(br, "topology change detected, %s\n",
1da177e4 LT	347	isroot ? "propagating" : "sending tcn bpdu");
	348
	349	if (isroot) {
	350	br->topology_change = 1;
	351	mod_timer(&br->topology_change_timer, jiffies
	352	+ br->bridge_forward_delay + br->bridge_max_age);
	353	} else if (!br->topology_change_detected) {
	354	br_transmit_tcn(br);
	355	mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
	356	}
	357
	358	br->topology_change_detected = 1;
	359	}
	360
	361	/* called under bridge lock */
	362	void br_config_bpdu_generation(struct net_bridge *br)
	363	{
	364	struct net_bridge_port *p;
	365
	366	list_for_each_entry(p, &br->port_list, list) {
	367	if (p->state != BR_STATE_DISABLED &&
	368	br_is_designated_port(p))
	369	br_transmit_config(p);
	370	}
	371	}
	372
	373	/* called under bridge lock */
160d73b8	374	static void br_reply(struct net_bridge_port *p)
1da177e4 LT	375	{
	376	br_transmit_config(p);
	377	}
	378
	379	/* called under bridge lock */
	380	void br_configuration_update(struct net_bridge *br)
	381	{
	382	br_root_selection(br);
	383	br_designated_port_selection(br);
	384	}
	385
	386	/* called under bridge lock */
	387	void br_become_designated_port(struct net_bridge_port *p)
	388	{
	389	struct net_bridge *br;
	390
	391	br = p->br;
	392	p->designated_root = br->designated_root;
	393	p->designated_cost = br->root_path_cost;
	394	p->designated_bridge = br->bridge_id;
	395	p->designated_port = p->port_id;
	396	}
	397
	398
	399	/* called under bridge lock */
	400	static void br_make_blocking(struct net_bridge_port *p)
	401	{
	402	if (p->state != BR_STATE_DISABLED &&
	403	p->state != BR_STATE_BLOCKING) {
	404	if (p->state == BR_STATE_FORWARDING \|\|
	405	p->state == BR_STATE_LEARNING)
	406	br_topology_change_detection(p->br);
	407
775dd692	408	br_set_state(p, BR_STATE_BLOCKING);
1da177e4	409	br_log_state(p);
4ecb961c	410	br_ifinfo_notify(RTM_NEWLINK, p);
4ecb961c	411
1da177e4 LT	412	del_timer(&p->forward_delay_timer);
	413	}
	414	}
	415
	416	/* called under bridge lock */
	417	static void br_make_forwarding(struct net_bridge_port *p)
	418	{
ef647f13	419	struct net_bridge *br = p->br;
9cde0708	420
ef647f13 SH	421	if (p->state != BR_STATE_BLOCKING)
	422	return;
	423
a461c029	424	if (br->stp_enabled == BR_NO_STP \|\| br->forward_delay == 0) {
775dd692	425	br_set_state(p, BR_STATE_FORWARDING);
ef647f13 SH	426	br_topology_change_detection(br);
ef647f13 SH	427	del_timer(&p->forward_delay_timer);
160d73b8	428	} else if (br->stp_enabled == BR_KERNEL_STP)
775dd692	429	br_set_state(p, BR_STATE_LISTENING);
ef647f13	430	else
775dd692	431	br_set_state(p, BR_STATE_LEARNING);
ef647f13 SH	432
ef647f13 SH	433	br_log_state(p);
4ecb961c	434	br_ifinfo_notify(RTM_NEWLINK, p);
ef647f13 SH	435
	436	if (br->forward_delay != 0)
	437	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
1da177e4 LT	438	}
	439
	440	/* called under bridge lock */
	441	void br_port_state_selection(struct net_bridge *br)
	442	{
	443	struct net_bridge_port *p;
1faa4356	444	unsigned int liveports = 0;
1da177e4 LT	445
1da177e4 LT	446	list_for_each_entry(p, &br->port_list, list) {
1faa4356	447	if (p->state == BR_STATE_DISABLED)
	448	continue;
	449
b03b6dd5 VD	450	/* Don't change port states if userspace is handling STP */
	451	if (br->stp_enabled != BR_USER_STP) {
	452	if (p->port_no == br->root_port) {
	453	p->config_pending = 0;
	454	p->topology_change_ack = 0;
	455	br_make_forwarding(p);
	456	} else if (br_is_designated_port(p)) {
	457	del_timer(&p->message_age_timer);
	458	br_make_forwarding(p);
	459	} else {
	460	p->config_pending = 0;
	461	p->topology_change_ack = 0;
	462	br_make_blocking(p);
	463	}
1da177e4 LT	464	}
1da177e4 LT	465
7ce42de1 NA	466	if (p->state != BR_STATE_BLOCKING)
7ce42de1 NA	467	br_multicast_enable_port(p);
9aa66382 NA	468	/* Multicast is not disabled for the port when it goes in
	469	* blocking state because the timers will expire and stop by
	470	* themselves without sending more queries.
	471	*/
1faa4356	472	if (p->state == BR_STATE_FORWARDING)
1faa4356	473	++liveports;
1da177e4	474	}
1faa4356	475
	476	if (liveports == 0)
	477	netif_carrier_off(br->dev);
	478	else
	479	netif_carrier_on(br->dev);
1da177e4 LT	480	}
	481
	482	/* called under bridge lock */
160d73b8	483	static void br_topology_change_acknowledge(struct net_bridge_port *p)
1da177e4 LT	484	{
	485	p->topology_change_ack = 1;
	486	br_transmit_config(p);
	487	}
	488
	489	/* called under bridge lock */
160d73b8	490	void br_received_config_bpdu(struct net_bridge_port *p,
160d73b8	491	const struct br_config_bpdu *bpdu)
1da177e4 LT	492	{
	493	struct net_bridge *br;
	494	int was_root;
9d6f229f	495
1da177e4 LT	496	br = p->br;
	497	was_root = br_is_root_bridge(br);
	498
	499	if (br_supersedes_port_info(p, bpdu)) {
	500	br_record_config_information(p, bpdu);
	501	br_configuration_update(br);
	502	br_port_state_selection(br);
	503
	504	if (!br_is_root_bridge(br) && was_root) {
	505	del_timer(&br->hello_timer);
	506	if (br->topology_change_detected) {
	507	del_timer(&br->topology_change_timer);
	508	br_transmit_tcn(br);
	509
9d6f229f	510	mod_timer(&br->tcn_timer,
1da177e4 LT	511	jiffies + br->bridge_hello_time);
	512	}
	513	}
	514
	515	if (p->port_no == br->root_port) {
	516	br_record_config_timeout_values(br, bpdu);
	517	br_config_bpdu_generation(br);
	518	if (bpdu->topology_change_ack)
	519	br_topology_change_acknowledged(br);
	520	}
9d6f229f YH	521	} else if (br_is_designated_port(p)) {
9d6f229f YH	522	br_reply(p);
1da177e4 LT	523	}
	524	}
	525
	526	/* called under bridge lock */
	527	void br_received_tcn_bpdu(struct net_bridge_port *p)
	528	{
	529	if (br_is_designated_port(p)) {
28a16c97	530	br_info(p->br, "port %u(%s) received tcn bpdu\n",
95c96174	531	(unsigned int) p->port_no, p->dev->name);
1da177e4 LT	532
	533	br_topology_change_detection(p->br);
	534	br_topology_change_acknowledge(p);
	535	}
	536	}
14f98f25	537
	538	/* Change bridge STP parameter */
	539	int br_set_hello_time(struct net_bridge *br, unsigned long val)
	540	{
	541	unsigned long t = clock_t_to_jiffies(val);
	542
	543	if (t < BR_MIN_HELLO_TIME \|\| t > BR_MAX_HELLO_TIME)
	544	return -ERANGE;
	545
	546	spin_lock_bh(&br->lock);
	547	br->bridge_hello_time = t;
	548	if (br_is_root_bridge(br))
	549	br->hello_time = br->bridge_hello_time;
	550	spin_unlock_bh(&br->lock);
	551	return 0;
	552	}
	553
	554	int br_set_max_age(struct net_bridge *br, unsigned long val)
	555	{
	556	unsigned long t = clock_t_to_jiffies(val);
	557
	558	if (t < BR_MIN_MAX_AGE \|\| t > BR_MAX_MAX_AGE)
	559	return -ERANGE;
	560
	561	spin_lock_bh(&br->lock);
	562	br->bridge_max_age = t;
	563	if (br_is_root_bridge(br))
	564	br->max_age = br->bridge_max_age;
	565	spin_unlock_bh(&br->lock);
	566	return 0;
	567
	568	}
	569
c62987bb SF	570	int br_set_ageing_time(struct net_bridge *br, u32 ageing_time)
	571	{
	572	struct switchdev_attr attr = {
	573	.id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
	574	.flags = SWITCHDEV_F_SKIP_EOPNOTSUPP,
	575	.u.ageing_time = ageing_time,
	576	};
	577	unsigned long t = clock_t_to_jiffies(ageing_time);
	578	int err;
	579
	580	if (t < BR_MIN_AGEING_TIME \|\| t > BR_MAX_AGEING_TIME)
	581	return -ERANGE;
	582
	583	err = switchdev_port_attr_set(br->dev, &attr);
	584	if (err)
	585	return err;
	586
	587	br->ageing_time = t;
	588	mod_timer(&br->gc_timer, jiffies);
	589
	590	return 0;
	591	}
	592
be4f154d HX	593	void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
	594	{
	595	br->bridge_forward_delay = t;
	596	if (br_is_root_bridge(br))
	597	br->forward_delay = br->bridge_forward_delay;
	598	}
	599
14f98f25	600	int br_set_forward_delay(struct net_bridge *br, unsigned long val)
	601	{
	602	unsigned long t = clock_t_to_jiffies(val);
8a921265	603	int err = -ERANGE;
14f98f25	604
34c2d9fb	605	spin_lock_bh(&br->lock);
8a921265 VY	606	if (br->stp_enabled != BR_NO_STP &&
	607	(t < BR_MIN_FORWARD_DELAY \|\| t > BR_MAX_FORWARD_DELAY))
	608	goto unlock;
	609
be4f154d	610	__br_set_forward_delay(br, t);
8a921265 VY	611	err = 0;
	612
	613	unlock:
14f98f25	614	spin_unlock_bh(&br->lock);
8a921265	615	return err;
14f98f25	616	}