[mirror_ubuntu-bionic-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)
{
	int err;

	p->state = state;
	err = switchdev_port_stp_update(p->dev, state);
	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_multicast_enable_port(p);
	br_log_state(p);
	br_ifinfo_notify(RTM_NEWLINK, p);

	if (br->forward_delay != 0)
		mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
}

/* called under bridge lock */
void br_port_state_selection(struct net_bridge *br)
{
	struct net_bridge_port *p;
	unsigned int liveports = 0;

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

		/* Don't change port states if userspace is handling STP */
		if (br->stp_enabled != BR_USER_STP) {
			if (p->port_no == br->root_port) {
				p->config_pending = 0;
				p->topology_change_ack = 0;
				br_make_forwarding(p);
			} else if (br_is_designated_port(p)) {
				del_timer(&p->message_age_timer);
				br_make_forwarding(p);
			} else {
				p->config_pending = 0;
				p->topology_change_ack = 0;
				br_make_blocking(p);
			}
		}

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

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

/* called under bridge lock */
static void br_topology_change_acknowledge(struct net_bridge_port *p)
{
	p->topology_change_ack = 1;
	br_transmit_config(p);
}

/* called under bridge lock */
void br_received_config_bpdu(struct net_bridge_port *p,
			     const struct br_config_bpdu *bpdu)
{
	struct net_bridge *br;
	int was_root;

	br = p->br;
	was_root = br_is_root_bridge(br);

	if (br_supersedes_port_info(p, bpdu)) {
		br_record_config_information(p, bpdu);
		br_configuration_update(br);
		br_port_state_selection(br);

		if (!br_is_root_bridge(br) && was_root) {
			del_timer(&br->hello_timer);
			if (br->topology_change_detected) {
				del_timer(&br->topology_change_timer);
				br_transmit_tcn(br);

				mod_timer(&br->tcn_timer,
					  jiffies + br->bridge_hello_time);
			}
		}

		if (p->port_no == br->root_port) {
			br_record_config_timeout_values(br, bpdu);
			br_config_bpdu_generation(br);
			if (bpdu->topology_change_ack)
				br_topology_change_acknowledged(br);
		}
	} else if (br_is_designated_port(p)) {
		br_reply(p);
	}
}

/* called under bridge lock */
void br_received_tcn_bpdu(struct net_bridge_port *p)
{
	if (br_is_designated_port(p)) {
		br_info(p->br, "port %u(%s) received tcn bpdu\n",
			(unsigned 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	{
38dcf357 SF	42	int err;
38dcf357 SF	43
775dd692	44	p->state = state;
ebb9a03a	45	err = switchdev_port_stp_update(p->dev, state);
38dcf357 SF	46	if (err && err != -EOPNOTSUPP)
	47	br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
	48	(unsigned int) p->port_no, p->dev->name);
775dd692 FF	49	}
775dd692 FF	50
1da177e4 LT	51	/* called under bridge lock */
	52	struct net_bridge_port br_get_port(struct net_bridge br, u16 port_no)
	53	{
	54	struct net_bridge_port *p;
	55
	56	list_for_each_entry_rcu(p, &br->port_list, list) {
	57	if (p->port_no == port_no)
	58	return p;
	59	}
	60
	61	return NULL;
	62	}
	63
	64	/* called under bridge lock */
9d6f229f	65	static int br_should_become_root_port(const struct net_bridge_port *p,
1da177e4 LT	66	u16 root_port)
	67	{
	68	struct net_bridge *br;
	69	struct net_bridge_port *rp;
	70	int t;
	71
	72	br = p->br;
	73	if (p->state == BR_STATE_DISABLED \|\|
	74	br_is_designated_port(p))
	75	return 0;
	76
	77	if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
	78	return 0;
	79
	80	if (!root_port)
	81	return 1;
	82
	83	rp = br_get_port(br, root_port);
	84
	85	t = memcmp(&p->designated_root, &rp->designated_root, 8);
	86	if (t < 0)
	87	return 1;
	88	else if (t > 0)
	89	return 0;
	90
	91	if (p->designated_cost + p->path_cost <
	92	rp->designated_cost + rp->path_cost)
	93	return 1;
	94	else if (p->designated_cost + p->path_cost >
	95	rp->designated_cost + rp->path_cost)
	96	return 0;
	97
	98	t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
	99	if (t < 0)
	100	return 1;
	101	else if (t > 0)
	102	return 0;
	103
	104	if (p->designated_port < rp->designated_port)
	105	return 1;
	106	else if (p->designated_port > rp->designated_port)
	107	return 0;
	108
	109	if (p->port_id < rp->port_id)
	110	return 1;
	111
	112	return 0;
	113	}
	114
1007dd1a	115	static void br_root_port_block(const struct net_bridge *br,
	116	struct net_bridge_port *p)
	117	{
	118
	119	br_notice(br, "port %u(%s) tried to become root port (blocked)",
	120	(unsigned int) p->port_no, p->dev->name);
	121
775dd692	122	br_set_state(p, BR_STATE_LISTENING);
1007dd1a	123	br_log_state(p);
	124	br_ifinfo_notify(RTM_NEWLINK, p);
	125
	126	if (br->forward_delay > 0)
	127	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
	128	}
	129
1da177e4 LT	130	/* called under bridge lock */
	131	static void br_root_selection(struct net_bridge *br)
	132	{
	133	struct net_bridge_port *p;
	134	u16 root_port = 0;
	135
	136	list_for_each_entry(p, &br->port_list, list) {
1007dd1a	137	if (!br_should_become_root_port(p, root_port))
	138	continue;
	139
	140	if (p->flags & BR_ROOT_BLOCK)
	141	br_root_port_block(br, p);
	142	else
1da177e4	143	root_port = p->port_no;
1da177e4 LT	144	}
	145
	146	br->root_port = root_port;
	147
	148	if (!root_port) {
	149	br->designated_root = br->bridge_id;
	150	br->root_path_cost = 0;
	151	} else {
	152	p = br_get_port(br, root_port);
	153	br->designated_root = p->designated_root;
	154	br->root_path_cost = p->designated_cost + p->path_cost;
	155	}
	156	}
	157
	158	/* called under bridge lock */
	159	void br_become_root_bridge(struct net_bridge *br)
	160	{
	161	br->max_age = br->bridge_max_age;
	162	br->hello_time = br->bridge_hello_time;
	163	br->forward_delay = br->bridge_forward_delay;
	164	br_topology_change_detection(br);
	165	del_timer(&br->tcn_timer);
	166
	167	if (br->dev->flags & IFF_UP) {
	168	br_config_bpdu_generation(br);
	169	mod_timer(&br->hello_timer, jiffies + br->hello_time);
	170	}
	171	}
	172
	173	/* called under bridge lock */
	174	void br_transmit_config(struct net_bridge_port *p)
	175	{
	176	struct br_config_bpdu bpdu;
	177	struct net_bridge *br;
	178
1da177e4 LT	179	if (timer_pending(&p->hold_timer)) {
	180	p->config_pending = 1;
	181	return;
	182	}
	183
	184	br = p->br;
	185
	186	bpdu.topology_change = br->topology_change;
	187	bpdu.topology_change_ack = p->topology_change_ack;
	188	bpdu.root = br->designated_root;
	189	bpdu.root_path_cost = br->root_path_cost;
	190	bpdu.bridge_id = br->bridge_id;
	191	bpdu.port_id = p->port_id;
	192	if (br_is_root_bridge(br))
	193	bpdu.message_age = 0;
	194	else {
	195	struct net_bridge_port *root
	196	= br_get_port(br, br->root_port);
0c03150e	197	bpdu.message_age = (jiffies - root->designated_age)
1da177e4 LT	198	+ MESSAGE_AGE_INCR;
	199	}
	200	bpdu.max_age = br->max_age;
	201	bpdu.hello_time = br->hello_time;
	202	bpdu.forward_delay = br->forward_delay;
	203
	204	if (bpdu.message_age < br->max_age) {
	205	br_send_config_bpdu(p, &bpdu);
	206	p->topology_change_ack = 0;
	207	p->config_pending = 0;
9a834b87 SH	208	mod_timer(&p->hold_timer,
9a834b87 SH	209	round_jiffies(jiffies + BR_HOLD_TIME));
1da177e4 LT	210	}
	211	}
	212
	213	/* called under bridge lock */
160d73b8	214	static void br_record_config_information(struct net_bridge_port *p,
160d73b8	215	const struct br_config_bpdu *bpdu)
1da177e4 LT	216	{
	217	p->designated_root = bpdu->root;
	218	p->designated_cost = bpdu->root_path_cost;
	219	p->designated_bridge = bpdu->bridge_id;
	220	p->designated_port = bpdu->port_id;
709e1b5c	221	p->designated_age = jiffies - bpdu->message_age;
1da177e4	222
9d6f229f	223	mod_timer(&p->message_age_timer, jiffies
9a062013	224	+ (bpdu->max_age - bpdu->message_age));
1da177e4 LT	225	}
	226
	227	/* called under bridge lock */
160d73b8	228	static void br_record_config_timeout_values(struct net_bridge *br,
1da177e4 LT	229	const struct br_config_bpdu *bpdu)
	230	{
	231	br->max_age = bpdu->max_age;
	232	br->hello_time = bpdu->hello_time;
	233	br->forward_delay = bpdu->forward_delay;
	234	br->topology_change = bpdu->topology_change;
	235	}
	236
	237	/* called under bridge lock */
	238	void br_transmit_tcn(struct net_bridge *br)
	239	{
91bc033c	240	struct net_bridge_port *p;
	241
	242	p = br_get_port(br, br->root_port);
	243	if (p)
	244	br_send_tcn_bpdu(p);
	245	else
	246	br_notice(br, "root port %u not found for topology notice\n",
	247	br->root_port);
1da177e4 LT	248	}
	249
	250	/* called under bridge lock */
	251	static int br_should_become_designated_port(const struct net_bridge_port *p)
	252	{
	253	struct net_bridge *br;
	254	int t;
	255
	256	br = p->br;
	257	if (br_is_designated_port(p))
	258	return 1;
	259
	260	if (memcmp(&p->designated_root, &br->designated_root, 8))
	261	return 1;
	262
	263	if (br->root_path_cost < p->designated_cost)
	264	return 1;
	265	else if (br->root_path_cost > p->designated_cost)
	266	return 0;
	267
	268	t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
	269	if (t < 0)
	270	return 1;
	271	else if (t > 0)
	272	return 0;
	273
	274	if (p->port_id < p->designated_port)
	275	return 1;
	276
	277	return 0;
	278	}
	279
	280	/* called under bridge lock */
	281	static void br_designated_port_selection(struct net_bridge *br)
	282	{
	283	struct net_bridge_port *p;
	284
	285	list_for_each_entry(p, &br->port_list, list) {
	286	if (p->state != BR_STATE_DISABLED &&
	287	br_should_become_designated_port(p))
	288	br_become_designated_port(p);
	289
	290	}
	291	}
	292
	293	/* called under bridge lock */
160d73b8	294	static int br_supersedes_port_info(const struct net_bridge_port *p,
160d73b8	295	const struct br_config_bpdu *bpdu)
1da177e4 LT	296	{
	297	int t;
	298
	299	t = memcmp(&bpdu->root, &p->designated_root, 8);
	300	if (t < 0)
	301	return 1;
	302	else if (t > 0)
	303	return 0;
	304
	305	if (bpdu->root_path_cost < p->designated_cost)
	306	return 1;
	307	else if (bpdu->root_path_cost > p->designated_cost)
	308	return 0;
	309
	310	t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
	311	if (t < 0)
	312	return 1;
	313	else if (t > 0)
	314	return 0;
	315
	316	if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
	317	return 1;
	318
	319	if (bpdu->port_id <= p->designated_port)
	320	return 1;
	321
	322	return 0;
	323	}
	324
	325	/* called under bridge lock */
160d73b8	326	static void br_topology_change_acknowledged(struct net_bridge *br)
1da177e4 LT	327	{
	328	br->topology_change_detected = 0;
	329	del_timer(&br->tcn_timer);
	330	}
	331
	332	/* called under bridge lock */
	333	void br_topology_change_detection(struct net_bridge *br)
	334	{
	335	int isroot = br_is_root_bridge(br);
	336
4f0611af SH	337	if (br->stp_enabled != BR_KERNEL_STP)
	338	return;
	339
28a16c97	340	br_info(br, "topology change detected, %s\n",
1da177e4 LT	341	isroot ? "propagating" : "sending tcn bpdu");
	342
	343	if (isroot) {
	344	br->topology_change = 1;
	345	mod_timer(&br->topology_change_timer, jiffies
	346	+ br->bridge_forward_delay + br->bridge_max_age);
	347	} else if (!br->topology_change_detected) {
	348	br_transmit_tcn(br);
	349	mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
	350	}
	351
	352	br->topology_change_detected = 1;
	353	}
	354
	355	/* called under bridge lock */
	356	void br_config_bpdu_generation(struct net_bridge *br)
	357	{
	358	struct net_bridge_port *p;
	359
	360	list_for_each_entry(p, &br->port_list, list) {
	361	if (p->state != BR_STATE_DISABLED &&
	362	br_is_designated_port(p))
	363	br_transmit_config(p);
	364	}
	365	}
	366
	367	/* called under bridge lock */
160d73b8	368	static void br_reply(struct net_bridge_port *p)
1da177e4 LT	369	{
	370	br_transmit_config(p);
	371	}
	372
	373	/* called under bridge lock */
	374	void br_configuration_update(struct net_bridge *br)
	375	{
	376	br_root_selection(br);
	377	br_designated_port_selection(br);
	378	}
	379
	380	/* called under bridge lock */
	381	void br_become_designated_port(struct net_bridge_port *p)
	382	{
	383	struct net_bridge *br;
	384
	385	br = p->br;
	386	p->designated_root = br->designated_root;
	387	p->designated_cost = br->root_path_cost;
	388	p->designated_bridge = br->bridge_id;
	389	p->designated_port = p->port_id;
	390	}
	391
	392
	393	/* called under bridge lock */
	394	static void br_make_blocking(struct net_bridge_port *p)
	395	{
	396	if (p->state != BR_STATE_DISABLED &&
	397	p->state != BR_STATE_BLOCKING) {
	398	if (p->state == BR_STATE_FORWARDING \|\|
	399	p->state == BR_STATE_LEARNING)
	400	br_topology_change_detection(p->br);
	401
775dd692	402	br_set_state(p, BR_STATE_BLOCKING);
1da177e4	403	br_log_state(p);
4ecb961c	404	br_ifinfo_notify(RTM_NEWLINK, p);
4ecb961c	405
1da177e4 LT	406	del_timer(&p->forward_delay_timer);
	407	}
	408	}
	409
	410	/* called under bridge lock */
	411	static void br_make_forwarding(struct net_bridge_port *p)
	412	{
ef647f13	413	struct net_bridge *br = p->br;
9cde0708	414
ef647f13 SH	415	if (p->state != BR_STATE_BLOCKING)
	416	return;
	417
a461c029	418	if (br->stp_enabled == BR_NO_STP \|\| br->forward_delay == 0) {
775dd692	419	br_set_state(p, BR_STATE_FORWARDING);
ef647f13 SH	420	br_topology_change_detection(br);
ef647f13 SH	421	del_timer(&p->forward_delay_timer);
160d73b8	422	} else if (br->stp_enabled == BR_KERNEL_STP)
775dd692	423	br_set_state(p, BR_STATE_LISTENING);
ef647f13	424	else
775dd692	425	br_set_state(p, BR_STATE_LEARNING);
ef647f13	426
3fe2d7c7	427	br_multicast_enable_port(p);
ef647f13	428	br_log_state(p);
4ecb961c	429	br_ifinfo_notify(RTM_NEWLINK, p);
ef647f13 SH	430
	431	if (br->forward_delay != 0)
	432	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
1da177e4 LT	433	}
	434
	435	/* called under bridge lock */
	436	void br_port_state_selection(struct net_bridge *br)
	437	{
	438	struct net_bridge_port *p;
1faa4356	439	unsigned int liveports = 0;
1da177e4 LT	440
1da177e4 LT	441	list_for_each_entry(p, &br->port_list, list) {
1faa4356	442	if (p->state == BR_STATE_DISABLED)
	443	continue;
	444
b03b6dd5 VD	445	/* Don't change port states if userspace is handling STP */
	446	if (br->stp_enabled != BR_USER_STP) {
	447	if (p->port_no == br->root_port) {
	448	p->config_pending = 0;
	449	p->topology_change_ack = 0;
	450	br_make_forwarding(p);
	451	} else if (br_is_designated_port(p)) {
	452	del_timer(&p->message_age_timer);
	453	br_make_forwarding(p);
	454	} else {
	455	p->config_pending = 0;
	456	p->topology_change_ack = 0;
	457	br_make_blocking(p);
	458	}
1da177e4 LT	459	}
1da177e4 LT	460
1faa4356	461	if (p->state == BR_STATE_FORWARDING)
1faa4356	462	++liveports;
1da177e4	463	}
1faa4356	464
	465	if (liveports == 0)
	466	netif_carrier_off(br->dev);
	467	else
	468	netif_carrier_on(br->dev);
1da177e4 LT	469	}
	470
	471	/* called under bridge lock */
160d73b8	472	static void br_topology_change_acknowledge(struct net_bridge_port *p)
1da177e4 LT	473	{
	474	p->topology_change_ack = 1;
	475	br_transmit_config(p);
	476	}
	477
	478	/* called under bridge lock */
160d73b8	479	void br_received_config_bpdu(struct net_bridge_port *p,
160d73b8	480	const struct br_config_bpdu *bpdu)
1da177e4 LT	481	{
	482	struct net_bridge *br;
	483	int was_root;
9d6f229f	484
1da177e4 LT	485	br = p->br;
	486	was_root = br_is_root_bridge(br);
	487
	488	if (br_supersedes_port_info(p, bpdu)) {
	489	br_record_config_information(p, bpdu);
	490	br_configuration_update(br);
	491	br_port_state_selection(br);
	492
	493	if (!br_is_root_bridge(br) && was_root) {
	494	del_timer(&br->hello_timer);
	495	if (br->topology_change_detected) {
	496	del_timer(&br->topology_change_timer);
	497	br_transmit_tcn(br);
	498
9d6f229f	499	mod_timer(&br->tcn_timer,
1da177e4 LT	500	jiffies + br->bridge_hello_time);
	501	}
	502	}
	503
	504	if (p->port_no == br->root_port) {
	505	br_record_config_timeout_values(br, bpdu);
	506	br_config_bpdu_generation(br);
	507	if (bpdu->topology_change_ack)
	508	br_topology_change_acknowledged(br);
	509	}
9d6f229f YH	510	} else if (br_is_designated_port(p)) {
9d6f229f YH	511	br_reply(p);
1da177e4 LT	512	}
	513	}
	514
	515	/* called under bridge lock */
	516	void br_received_tcn_bpdu(struct net_bridge_port *p)
	517	{
	518	if (br_is_designated_port(p)) {
28a16c97	519	br_info(p->br, "port %u(%s) received tcn bpdu\n",
95c96174	520	(unsigned int) p->port_no, p->dev->name);
1da177e4 LT	521
	522	br_topology_change_detection(p->br);
	523	br_topology_change_acknowledge(p);
	524	}
	525	}
14f98f25	526
	527	/* Change bridge STP parameter */
	528	int br_set_hello_time(struct net_bridge *br, unsigned long val)
	529	{
	530	unsigned long t = clock_t_to_jiffies(val);
	531
	532	if (t < BR_MIN_HELLO_TIME \|\| t > BR_MAX_HELLO_TIME)
	533	return -ERANGE;
	534
	535	spin_lock_bh(&br->lock);
	536	br->bridge_hello_time = t;
	537	if (br_is_root_bridge(br))
	538	br->hello_time = br->bridge_hello_time;
	539	spin_unlock_bh(&br->lock);
	540	return 0;
	541	}
	542
	543	int br_set_max_age(struct net_bridge *br, unsigned long val)
	544	{
	545	unsigned long t = clock_t_to_jiffies(val);
	546
	547	if (t < BR_MIN_MAX_AGE \|\| t > BR_MAX_MAX_AGE)
	548	return -ERANGE;
	549
	550	spin_lock_bh(&br->lock);
	551	br->bridge_max_age = t;
	552	if (br_is_root_bridge(br))
	553	br->max_age = br->bridge_max_age;
	554	spin_unlock_bh(&br->lock);
	555	return 0;
	556
	557	}
	558
be4f154d HX	559	void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
	560	{
	561	br->bridge_forward_delay = t;
	562	if (br_is_root_bridge(br))
	563	br->forward_delay = br->bridge_forward_delay;
	564	}
	565
14f98f25	566	int br_set_forward_delay(struct net_bridge *br, unsigned long val)
	567	{
	568	unsigned long t = clock_t_to_jiffies(val);
be4f154d	569	int err = -ERANGE;
14f98f25	570
be4f154d	571	spin_lock_bh(&br->lock);
14f98f25	572	if (br->stp_enabled != BR_NO_STP &&
14f98f25	573	(t < BR_MIN_FORWARD_DELAY \|\| t > BR_MAX_FORWARD_DELAY))
be4f154d	574	goto unlock;
14f98f25	575
be4f154d HX	576	__br_set_forward_delay(br, t);
	577	err = 0;
	578
	579	unlock:
14f98f25	580	spin_unlock_bh(&br->lock);
be4f154d	581	return err;
14f98f25	582	}