[linux-block.git] / net / bridge / br_stp.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	Spanning tree protocol; generic parts
 *	Linux ethernet bridge
 *
 *	Authors:
 *	Lennert Buytenhek		<buytenh@gnu.org>
 */
#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_set_state(struct net_bridge_port *p, unsigned int state)
{
	struct switchdev_attr attr = {
		.orig_dev = p->dev,
		.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 && err != -EOPNOTSUPP)
		br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
				(unsigned int) p->port_no, p->dev->name);
	else
		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]);

	if (p->br->stp_enabled == BR_KERNEL_STP) {
		switch (p->state) {
		case BR_STATE_BLOCKING:
			p->stp_xstats.transition_blk++;
			break;
		case BR_STATE_FORWARDING:
			p->stp_xstats.transition_fwd++;
			break;
		}
	}
}

/* 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,
				lockdep_is_held(&br->lock)) {
		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_ifinfo_notify(RTM_NEWLINK, NULL, 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_set_topology_change(br, 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_set_topology_change(br, 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_ifinfo_notify(RTM_NEWLINK, NULL, 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_ifinfo_notify(RTM_NEWLINK, NULL, 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;

	p->stp_xstats.rx_bpdu++;

	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)
{
	p->stp_xstats.rx_tcn++;

	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;

}

/* called under bridge lock */
int __set_ageing_time(struct net_device *dev, unsigned long t)
{
	struct switchdev_attr attr = {
		.orig_dev = dev,
		.id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
		.flags = SWITCHDEV_F_SKIP_EOPNOTSUPP | SWITCHDEV_F_DEFER,
		.u.ageing_time = jiffies_to_clock_t(t),
	};
	int err;

	err = switchdev_port_attr_set(dev, &attr);
	if (err && err != -EOPNOTSUPP)
		return err;

	return 0;
}

/* Set time interval that dynamic forwarding entries live
 * For pure software bridge, allow values outside the 802.1
 * standard specification for special cases:
 *  0 - entry never ages (all permanant)
 *  1 - entry disappears (no persistance)
 *
 * Offloaded switch entries maybe more restrictive
 */
int br_set_ageing_time(struct net_bridge *br, clock_t ageing_time)
{
	unsigned long t = clock_t_to_jiffies(ageing_time);
	int err;

	err = __set_ageing_time(br->dev, t);
	if (err)
		return err;

	spin_lock_bh(&br->lock);
	br->bridge_ageing_time = t;
	br->ageing_time = t;
	spin_unlock_bh(&br->lock);

	mod_delayed_work(system_long_wq, &br->gc_work, 0);

	return 0;
}

/* called under bridge lock */
void __br_set_topology_change(struct net_bridge *br, unsigned char val)
{
	unsigned long t;
	int err;

	if (br->stp_enabled == BR_KERNEL_STP && br->topology_change != val) {
		/* On topology change, set the bridge ageing time to twice the
		 * forward delay. Otherwise, restore its default ageing time.
		 */

		if (val) {
			t = 2 * br->forward_delay;
			br_debug(br, "decreasing ageing time to %lu\n", t);
		} else {
			t = br->bridge_ageing_time;
			br_debug(br, "restoring ageing time to %lu\n", t);
		}

		err = __set_ageing_time(br->dev, t);
		if (err)
			br_warn(br, "error offloading ageing time\n");
		else
			br->ageing_time = t;
	}

	br->topology_change = val;
}

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
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* Spanning tree protocol; generic parts
	4	* Linux ethernet bridge
	5	*
	6	* Authors:
	7	* Lennert Buytenhek <buytenh@gnu.org>
1da177e4 LT	8	*/
1da177e4 LT	9	#include <linux/kernel.h>
82524746	10	#include <linux/rculist.h>
38dcf357	11	#include <net/switchdev.h>
1da177e4 LT	12
	13	#include "br_private.h"
	14	#include "br_private_stp.h"
	15
	16	/* since time values in bpdu are in jiffies and then scaled (1/256)
aaca735f	17	* before sending, make sure that is at least one STP tick.
1da177e4	18	*/
aaca735f	19	#define MESSAGE_AGE_INCR ((HZ / 256) + 1)
1da177e4	20
36cbd3dc	21	static const char *const br_port_state_names[] = {
9d6f229f	22	[BR_STATE_DISABLED] = "disabled",
1da177e4	23	[BR_STATE_LISTENING] = "listening",
9d6f229f YH	24	[BR_STATE_LEARNING] = "learning",
9d6f229f YH	25	[BR_STATE_FORWARDING] = "forwarding",
1da177e4 LT	26	[BR_STATE_BLOCKING] = "blocking",
	27	};
	28
775dd692 FF	29	void br_set_state(struct net_bridge_port *p, unsigned int state)
775dd692 FF	30	{
35636062	31	struct switchdev_attr attr = {
6ff64f6f	32	.orig_dev = p->dev,
1f868398	33	.id = SWITCHDEV_ATTR_ID_PORT_STP_STATE,
0bc05d58	34	.flags = SWITCHDEV_F_DEFER,
42275bd8	35	.u.stp_state = state,
35636062	36	};
38dcf357 SF	37	int err;
38dcf357 SF	38
775dd692	39	p->state = state;
35636062	40	err = switchdev_port_attr_set(p->dev, &attr);
bbe14f54	41	if (err && err != -EOPNOTSUPP)
38dcf357 SF	42	br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
38dcf357 SF	43	(unsigned int) p->port_no, p->dev->name);
7c25b16d VD	44	else
	45	br_info(p->br, "port %u(%s) entered %s state\n",
	46	(unsigned int) p->port_no, p->dev->name,
	47	br_port_state_names[p->state]);
de179966 VD	48
	49	if (p->br->stp_enabled == BR_KERNEL_STP) {
	50	switch (p->state) {
	51	case BR_STATE_BLOCKING:
	52	p->stp_xstats.transition_blk++;
	53	break;
	54	case BR_STATE_FORWARDING:
	55	p->stp_xstats.transition_fwd++;
	56	break;
	57	}
	58	}
775dd692 FF	59	}
775dd692 FF	60
1da177e4 LT	61	/* called under bridge lock */
	62	struct net_bridge_port br_get_port(struct net_bridge br, u16 port_no)
	63	{
	64	struct net_bridge_port *p;
	65
33c4acbe MB	66	list_for_each_entry_rcu(p, &br->port_list, list,
33c4acbe MB	67	lockdep_is_held(&br->lock)) {
1da177e4 LT	68	if (p->port_no == port_no)
	69	return p;
	70	}
	71
	72	return NULL;
	73	}
	74
	75	/* called under bridge lock */
9d6f229f	76	static int br_should_become_root_port(const struct net_bridge_port *p,
1da177e4 LT	77	u16 root_port)
	78	{
	79	struct net_bridge *br;
	80	struct net_bridge_port *rp;
	81	int t;
	82
	83	br = p->br;
	84	if (p->state == BR_STATE_DISABLED \|\|
	85	br_is_designated_port(p))
	86	return 0;
	87
	88	if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
	89	return 0;
	90
	91	if (!root_port)
	92	return 1;
	93
	94	rp = br_get_port(br, root_port);
	95
	96	t = memcmp(&p->designated_root, &rp->designated_root, 8);
	97	if (t < 0)
	98	return 1;
	99	else if (t > 0)
	100	return 0;
	101
	102	if (p->designated_cost + p->path_cost <
	103	rp->designated_cost + rp->path_cost)
	104	return 1;
	105	else if (p->designated_cost + p->path_cost >
	106	rp->designated_cost + rp->path_cost)
	107	return 0;
	108
	109	t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
	110	if (t < 0)
	111	return 1;
	112	else if (t > 0)
	113	return 0;
	114
	115	if (p->designated_port < rp->designated_port)
	116	return 1;
	117	else if (p->designated_port > rp->designated_port)
	118	return 0;
	119
	120	if (p->port_id < rp->port_id)
	121	return 1;
	122
	123	return 0;
	124	}
	125
1007dd1a	126	static void br_root_port_block(const struct net_bridge *br,
	127	struct net_bridge_port *p)
	128	{
	129
	130	br_notice(br, "port %u(%s) tried to become root port (blocked)",
	131	(unsigned int) p->port_no, p->dev->name);
	132
775dd692	133	br_set_state(p, BR_STATE_LISTENING);
92899063	134	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
1007dd1a	135
	136	if (br->forward_delay > 0)
	137	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
	138	}
	139
1da177e4 LT	140	/* called under bridge lock */
	141	static void br_root_selection(struct net_bridge *br)
	142	{
	143	struct net_bridge_port *p;
	144	u16 root_port = 0;
	145
	146	list_for_each_entry(p, &br->port_list, list) {
1007dd1a	147	if (!br_should_become_root_port(p, root_port))
	148	continue;
	149
	150	if (p->flags & BR_ROOT_BLOCK)
	151	br_root_port_block(br, p);
	152	else
1da177e4	153	root_port = p->port_no;
1da177e4 LT	154	}
	155
	156	br->root_port = root_port;
	157
	158	if (!root_port) {
	159	br->designated_root = br->bridge_id;
	160	br->root_path_cost = 0;
	161	} else {
	162	p = br_get_port(br, root_port);
	163	br->designated_root = p->designated_root;
	164	br->root_path_cost = p->designated_cost + p->path_cost;
	165	}
	166	}
	167
	168	/* called under bridge lock */
	169	void br_become_root_bridge(struct net_bridge *br)
	170	{
	171	br->max_age = br->bridge_max_age;
	172	br->hello_time = br->bridge_hello_time;
	173	br->forward_delay = br->bridge_forward_delay;
	174	br_topology_change_detection(br);
	175	del_timer(&br->tcn_timer);
	176
	177	if (br->dev->flags & IFF_UP) {
	178	br_config_bpdu_generation(br);
	179	mod_timer(&br->hello_timer, jiffies + br->hello_time);
	180	}
	181	}
	182
	183	/* called under bridge lock */
	184	void br_transmit_config(struct net_bridge_port *p)
	185	{
	186	struct br_config_bpdu bpdu;
	187	struct net_bridge *br;
	188
1da177e4 LT	189	if (timer_pending(&p->hold_timer)) {
	190	p->config_pending = 1;
	191	return;
	192	}
	193
	194	br = p->br;
	195
	196	bpdu.topology_change = br->topology_change;
	197	bpdu.topology_change_ack = p->topology_change_ack;
	198	bpdu.root = br->designated_root;
	199	bpdu.root_path_cost = br->root_path_cost;
	200	bpdu.bridge_id = br->bridge_id;
	201	bpdu.port_id = p->port_id;
	202	if (br_is_root_bridge(br))
	203	bpdu.message_age = 0;
	204	else {
	205	struct net_bridge_port *root
	206	= br_get_port(br, br->root_port);
0c03150e	207	bpdu.message_age = (jiffies - root->designated_age)
1da177e4 LT	208	+ MESSAGE_AGE_INCR;
	209	}
	210	bpdu.max_age = br->max_age;
	211	bpdu.hello_time = br->hello_time;
	212	bpdu.forward_delay = br->forward_delay;
	213
	214	if (bpdu.message_age < br->max_age) {
	215	br_send_config_bpdu(p, &bpdu);
	216	p->topology_change_ack = 0;
	217	p->config_pending = 0;
76b91c32 NA	218	if (p->br->stp_enabled == BR_KERNEL_STP)
	219	mod_timer(&p->hold_timer,
	220	round_jiffies(jiffies + BR_HOLD_TIME));
1da177e4 LT	221	}
	222	}
	223
	224	/* called under bridge lock */
160d73b8	225	static void br_record_config_information(struct net_bridge_port *p,
160d73b8	226	const struct br_config_bpdu *bpdu)
1da177e4 LT	227	{
	228	p->designated_root = bpdu->root;
	229	p->designated_cost = bpdu->root_path_cost;
	230	p->designated_bridge = bpdu->bridge_id;
	231	p->designated_port = bpdu->port_id;
709e1b5c	232	p->designated_age = jiffies - bpdu->message_age;
1da177e4	233
9d6f229f	234	mod_timer(&p->message_age_timer, jiffies
9a062013	235	+ (bpdu->max_age - bpdu->message_age));
1da177e4 LT	236	}
	237
	238	/* called under bridge lock */
160d73b8	239	static void br_record_config_timeout_values(struct net_bridge *br,
1da177e4 LT	240	const struct br_config_bpdu *bpdu)
	241	{
	242	br->max_age = bpdu->max_age;
	243	br->hello_time = bpdu->hello_time;
	244	br->forward_delay = bpdu->forward_delay;
8384b5f5	245	__br_set_topology_change(br, bpdu->topology_change);
1da177e4 LT	246	}
	247
	248	/* called under bridge lock */
	249	void br_transmit_tcn(struct net_bridge *br)
	250	{
91bc033c	251	struct net_bridge_port *p;
	252
	253	p = br_get_port(br, br->root_port);
	254	if (p)
	255	br_send_tcn_bpdu(p);
	256	else
	257	br_notice(br, "root port %u not found for topology notice\n",
	258	br->root_port);
1da177e4 LT	259	}
	260
	261	/* called under bridge lock */
	262	static int br_should_become_designated_port(const struct net_bridge_port *p)
	263	{
	264	struct net_bridge *br;
	265	int t;
	266
	267	br = p->br;
	268	if (br_is_designated_port(p))
	269	return 1;
	270
	271	if (memcmp(&p->designated_root, &br->designated_root, 8))
	272	return 1;
	273
	274	if (br->root_path_cost < p->designated_cost)
	275	return 1;
	276	else if (br->root_path_cost > p->designated_cost)
	277	return 0;
	278
	279	t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
	280	if (t < 0)
	281	return 1;
	282	else if (t > 0)
	283	return 0;
	284
	285	if (p->port_id < p->designated_port)
	286	return 1;
	287
	288	return 0;
	289	}
	290
	291	/* called under bridge lock */
	292	static void br_designated_port_selection(struct net_bridge *br)
	293	{
	294	struct net_bridge_port *p;
	295
	296	list_for_each_entry(p, &br->port_list, list) {
	297	if (p->state != BR_STATE_DISABLED &&
	298	br_should_become_designated_port(p))
	299	br_become_designated_port(p);
	300
	301	}
	302	}
	303
	304	/* called under bridge lock */
160d73b8	305	static int br_supersedes_port_info(const struct net_bridge_port *p,
160d73b8	306	const struct br_config_bpdu *bpdu)
1da177e4 LT	307	{
	308	int t;
	309
	310	t = memcmp(&bpdu->root, &p->designated_root, 8);
	311	if (t < 0)
	312	return 1;
	313	else if (t > 0)
	314	return 0;
	315
	316	if (bpdu->root_path_cost < p->designated_cost)
	317	return 1;
	318	else if (bpdu->root_path_cost > p->designated_cost)
	319	return 0;
	320
	321	t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
	322	if (t < 0)
	323	return 1;
	324	else if (t > 0)
	325	return 0;
	326
	327	if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
	328	return 1;
	329
	330	if (bpdu->port_id <= p->designated_port)
	331	return 1;
	332
	333	return 0;
	334	}
	335
	336	/* called under bridge lock */
160d73b8	337	static void br_topology_change_acknowledged(struct net_bridge *br)
1da177e4 LT	338	{
	339	br->topology_change_detected = 0;
	340	del_timer(&br->tcn_timer);
	341	}
	342
	343	/* called under bridge lock */
	344	void br_topology_change_detection(struct net_bridge *br)
	345	{
	346	int isroot = br_is_root_bridge(br);
	347
4f0611af SH	348	if (br->stp_enabled != BR_KERNEL_STP)
	349	return;
	350
28a16c97	351	br_info(br, "topology change detected, %s\n",
1da177e4 LT	352	isroot ? "propagating" : "sending tcn bpdu");
	353
	354	if (isroot) {
8384b5f5	355	__br_set_topology_change(br, 1);
1da177e4 LT	356	mod_timer(&br->topology_change_timer, jiffies
	357	+ br->bridge_forward_delay + br->bridge_max_age);
	358	} else if (!br->topology_change_detected) {
	359	br_transmit_tcn(br);
	360	mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
	361	}
	362
	363	br->topology_change_detected = 1;
	364	}
	365
	366	/* called under bridge lock */
	367	void br_config_bpdu_generation(struct net_bridge *br)
	368	{
	369	struct net_bridge_port *p;
	370
	371	list_for_each_entry(p, &br->port_list, list) {
	372	if (p->state != BR_STATE_DISABLED &&
	373	br_is_designated_port(p))
	374	br_transmit_config(p);
	375	}
	376	}
	377
	378	/* called under bridge lock */
160d73b8	379	static void br_reply(struct net_bridge_port *p)
1da177e4 LT	380	{
	381	br_transmit_config(p);
	382	}
	383
	384	/* called under bridge lock */
	385	void br_configuration_update(struct net_bridge *br)
	386	{
	387	br_root_selection(br);
	388	br_designated_port_selection(br);
	389	}
	390
	391	/* called under bridge lock */
	392	void br_become_designated_port(struct net_bridge_port *p)
	393	{
	394	struct net_bridge *br;
	395
	396	br = p->br;
	397	p->designated_root = br->designated_root;
	398	p->designated_cost = br->root_path_cost;
	399	p->designated_bridge = br->bridge_id;
	400	p->designated_port = p->port_id;
	401	}
	402
	403
	404	/* called under bridge lock */
	405	static void br_make_blocking(struct net_bridge_port *p)
	406	{
	407	if (p->state != BR_STATE_DISABLED &&
	408	p->state != BR_STATE_BLOCKING) {
	409	if (p->state == BR_STATE_FORWARDING \|\|
	410	p->state == BR_STATE_LEARNING)
	411	br_topology_change_detection(p->br);
	412
775dd692	413	br_set_state(p, BR_STATE_BLOCKING);
92899063	414	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
4ecb961c	415
1da177e4 LT	416	del_timer(&p->forward_delay_timer);
	417	}
	418	}
	419
	420	/* called under bridge lock */
	421	static void br_make_forwarding(struct net_bridge_port *p)
	422	{
ef647f13	423	struct net_bridge *br = p->br;
9cde0708	424
ef647f13 SH	425	if (p->state != BR_STATE_BLOCKING)
	426	return;
	427
a461c029	428	if (br->stp_enabled == BR_NO_STP \|\| br->forward_delay == 0) {
775dd692	429	br_set_state(p, BR_STATE_FORWARDING);
ef647f13 SH	430	br_topology_change_detection(br);
ef647f13 SH	431	del_timer(&p->forward_delay_timer);
160d73b8	432	} else if (br->stp_enabled == BR_KERNEL_STP)
775dd692	433	br_set_state(p, BR_STATE_LISTENING);
ef647f13	434	else
775dd692	435	br_set_state(p, BR_STATE_LEARNING);
ef647f13	436
92899063	437	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
ef647f13 SH	438
	439	if (br->forward_delay != 0)
	440	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
1da177e4 LT	441	}
	442
	443	/* called under bridge lock */
	444	void br_port_state_selection(struct net_bridge *br)
	445	{
	446	struct net_bridge_port *p;
1faa4356	447	unsigned int liveports = 0;
1da177e4 LT	448
1da177e4 LT	449	list_for_each_entry(p, &br->port_list, list) {
1faa4356	450	if (p->state == BR_STATE_DISABLED)
	451	continue;
	452
b03b6dd5 VD	453	/* Don't change port states if userspace is handling STP */
	454	if (br->stp_enabled != BR_USER_STP) {
	455	if (p->port_no == br->root_port) {
	456	p->config_pending = 0;
	457	p->topology_change_ack = 0;
	458	br_make_forwarding(p);
	459	} else if (br_is_designated_port(p)) {
	460	del_timer(&p->message_age_timer);
	461	br_make_forwarding(p);
	462	} else {
	463	p->config_pending = 0;
	464	p->topology_change_ack = 0;
	465	br_make_blocking(p);
	466	}
1da177e4 LT	467	}
1da177e4 LT	468
7ce42de1 NA	469	if (p->state != BR_STATE_BLOCKING)
7ce42de1 NA	470	br_multicast_enable_port(p);
9aa66382 NA	471	/* Multicast is not disabled for the port when it goes in
	472	* blocking state because the timers will expire and stop by
	473	* themselves without sending more queries.
	474	*/
1faa4356	475	if (p->state == BR_STATE_FORWARDING)
1faa4356	476	++liveports;
1da177e4	477	}
1faa4356	478
	479	if (liveports == 0)
	480	netif_carrier_off(br->dev);
	481	else
	482	netif_carrier_on(br->dev);
1da177e4 LT	483	}
	484
	485	/* called under bridge lock */
160d73b8	486	static void br_topology_change_acknowledge(struct net_bridge_port *p)
1da177e4 LT	487	{
	488	p->topology_change_ack = 1;
	489	br_transmit_config(p);
	490	}
	491
	492	/* called under bridge lock */
160d73b8	493	void br_received_config_bpdu(struct net_bridge_port *p,
160d73b8	494	const struct br_config_bpdu *bpdu)
1da177e4 LT	495	{
	496	struct net_bridge *br;
	497	int was_root;
9d6f229f	498
de179966 VD	499	p->stp_xstats.rx_bpdu++;
de179966 VD	500
1da177e4 LT	501	br = p->br;
	502	was_root = br_is_root_bridge(br);
	503
	504	if (br_supersedes_port_info(p, bpdu)) {
	505	br_record_config_information(p, bpdu);
	506	br_configuration_update(br);
	507	br_port_state_selection(br);
	508
	509	if (!br_is_root_bridge(br) && was_root) {
	510	del_timer(&br->hello_timer);
	511	if (br->topology_change_detected) {
	512	del_timer(&br->topology_change_timer);
	513	br_transmit_tcn(br);
	514
9d6f229f	515	mod_timer(&br->tcn_timer,
1da177e4 LT	516	jiffies + br->bridge_hello_time);
	517	}
	518	}
	519
	520	if (p->port_no == br->root_port) {
	521	br_record_config_timeout_values(br, bpdu);
	522	br_config_bpdu_generation(br);
	523	if (bpdu->topology_change_ack)
	524	br_topology_change_acknowledged(br);
	525	}
9d6f229f YH	526	} else if (br_is_designated_port(p)) {
9d6f229f YH	527	br_reply(p);
1da177e4 LT	528	}
	529	}
	530
	531	/* called under bridge lock */
	532	void br_received_tcn_bpdu(struct net_bridge_port *p)
	533	{
de179966 VD	534	p->stp_xstats.rx_tcn++;
de179966 VD	535
1da177e4	536	if (br_is_designated_port(p)) {
28a16c97	537	br_info(p->br, "port %u(%s) received tcn bpdu\n",
95c96174	538	(unsigned int) p->port_no, p->dev->name);
1da177e4 LT	539
	540	br_topology_change_detection(p->br);
	541	br_topology_change_acknowledge(p);
	542	}
	543	}
14f98f25	544
	545	/* Change bridge STP parameter */
	546	int br_set_hello_time(struct net_bridge *br, unsigned long val)
	547	{
	548	unsigned long t = clock_t_to_jiffies(val);
	549
	550	if (t < BR_MIN_HELLO_TIME \|\| t > BR_MAX_HELLO_TIME)
	551	return -ERANGE;
	552
	553	spin_lock_bh(&br->lock);
	554	br->bridge_hello_time = t;
	555	if (br_is_root_bridge(br))
	556	br->hello_time = br->bridge_hello_time;
	557	spin_unlock_bh(&br->lock);
	558	return 0;
	559	}
	560
	561	int br_set_max_age(struct net_bridge *br, unsigned long val)
	562	{
	563	unsigned long t = clock_t_to_jiffies(val);
	564
	565	if (t < BR_MIN_MAX_AGE \|\| t > BR_MAX_MAX_AGE)
	566	return -ERANGE;
	567
	568	spin_lock_bh(&br->lock);
	569	br->bridge_max_age = t;
	570	if (br_is_root_bridge(br))
	571	br->max_age = br->bridge_max_age;
	572	spin_unlock_bh(&br->lock);
	573	return 0;
	574
	575	}
	576
82dd4332 VD	577	/* called under bridge lock */
	578	int __set_ageing_time(struct net_device *dev, unsigned long t)
	579	{
	580	struct switchdev_attr attr = {
	581	.orig_dev = dev,
	582	.id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
	583	.flags = SWITCHDEV_F_SKIP_EOPNOTSUPP \| SWITCHDEV_F_DEFER,
	584	.u.ageing_time = jiffies_to_clock_t(t),
	585	};
	586	int err;
	587
	588	err = switchdev_port_attr_set(dev, &attr);
	589	if (err && err != -EOPNOTSUPP)
	590	return err;
	591
	592	return 0;
	593	}
	594
4c656c13 SH	595	/* Set time interval that dynamic forwarding entries live
	596	* For pure software bridge, allow values outside the 802.1
	597	* standard specification for special cases:
	598	* 0 - entry never ages (all permanant)
	599	* 1 - entry disappears (no persistance)
	600	*
	601	* Offloaded switch entries maybe more restrictive
	602	*/
9e0b27fe	603	int br_set_ageing_time(struct net_bridge *br, clock_t ageing_time)
c62987bb	604	{
c62987bb SF	605	unsigned long t = clock_t_to_jiffies(ageing_time);
	606	int err;
	607
82dd4332 VD	608	err = __set_ageing_time(br->dev, t);
82dd4332 VD	609	if (err)
c62987bb SF	610	return err;
c62987bb SF	611
34d8acd8 VD	612	spin_lock_bh(&br->lock);
34d8acd8 VD	613	br->bridge_ageing_time = t;
c62987bb	614	br->ageing_time = t;
34d8acd8 VD	615	spin_unlock_bh(&br->lock);
34d8acd8 VD	616
f7cdee8a	617	mod_delayed_work(system_long_wq, &br->gc_work, 0);
c62987bb SF	618
	619	return 0;
	620	}
	621
8384b5f5 VD	622	/* called under bridge lock */
	623	void __br_set_topology_change(struct net_bridge *br, unsigned char val)
	624	{
34d8acd8 VD	625	unsigned long t;
	626	int err;
	627
	628	if (br->stp_enabled == BR_KERNEL_STP && br->topology_change != val) {
	629	/* On topology change, set the bridge ageing time to twice the
	630	* forward delay. Otherwise, restore its default ageing time.
	631	*/
	632
	633	if (val) {
	634	t = 2 * br->forward_delay;
	635	br_debug(br, "decreasing ageing time to %lu\n", t);
	636	} else {
	637	t = br->bridge_ageing_time;
	638	br_debug(br, "restoring ageing time to %lu\n", t);
	639	}
	640
	641	err = __set_ageing_time(br->dev, t);
	642	if (err)
	643	br_warn(br, "error offloading ageing time\n");
	644	else
	645	br->ageing_time = t;
	646	}
	647
8384b5f5 VD	648	br->topology_change = val;
	649	}
	650
be4f154d HX	651	void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
	652	{
	653	br->bridge_forward_delay = t;
	654	if (br_is_root_bridge(br))
	655	br->forward_delay = br->bridge_forward_delay;
	656	}
	657
14f98f25	658	int br_set_forward_delay(struct net_bridge *br, unsigned long val)
	659	{
	660	unsigned long t = clock_t_to_jiffies(val);
8a921265	661	int err = -ERANGE;
14f98f25	662
34c2d9fb	663	spin_lock_bh(&br->lock);
8a921265 VY	664	if (br->stp_enabled != BR_NO_STP &&
	665	(t < BR_MIN_FORWARD_DELAY \|\| t > BR_MAX_FORWARD_DELAY))
	666	goto unlock;
	667
be4f154d	668	__br_set_forward_delay(br, t);
8a921265 VY	669	err = 0;
	670
	671	unlock:
14f98f25	672	spin_unlock_bh(&br->lock);
8a921265	673	return err;
14f98f25	674	}