[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;

	/* Don't change the state of the ports if they are driven by a different
	 * protocol.
	 */
	if (p->flags & BR_MRP_AWARE)
		return;

	p->state = state;
	err = switchdev_port_attr_set(p->dev, &attr, NULL);
	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, NULL);
	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 permanent)
 *  1 - entry disappears (no persistence)
 *
 * 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
419dba8a HV	39	/* Don't change the state of the ports if they are driven by a different
	40	* protocol.
	41	*/
	42	if (p->flags & BR_MRP_AWARE)
	43	return;
	44
775dd692	45	p->state = state;
dcbdf135	46	err = switchdev_port_attr_set(p->dev, &attr, NULL);
bbe14f54	47	if (err && err != -EOPNOTSUPP)
38dcf357 SF	48	br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
38dcf357 SF	49	(unsigned int) p->port_no, p->dev->name);
7c25b16d VD	50	else
	51	br_info(p->br, "port %u(%s) entered %s state\n",
	52	(unsigned int) p->port_no, p->dev->name,
	53	br_port_state_names[p->state]);
de179966 VD	54
	55	if (p->br->stp_enabled == BR_KERNEL_STP) {
	56	switch (p->state) {
	57	case BR_STATE_BLOCKING:
	58	p->stp_xstats.transition_blk++;
	59	break;
	60	case BR_STATE_FORWARDING:
	61	p->stp_xstats.transition_fwd++;
	62	break;
	63	}
	64	}
775dd692 FF	65	}
775dd692 FF	66
1da177e4 LT	67	/* called under bridge lock */
	68	struct net_bridge_port br_get_port(struct net_bridge br, u16 port_no)
	69	{
	70	struct net_bridge_port *p;
	71
33c4acbe MB	72	list_for_each_entry_rcu(p, &br->port_list, list,
33c4acbe MB	73	lockdep_is_held(&br->lock)) {
1da177e4 LT	74	if (p->port_no == port_no)
	75	return p;
	76	}
	77
	78	return NULL;
	79	}
	80
	81	/* called under bridge lock */
9d6f229f	82	static int br_should_become_root_port(const struct net_bridge_port *p,
1da177e4 LT	83	u16 root_port)
	84	{
	85	struct net_bridge *br;
	86	struct net_bridge_port *rp;
	87	int t;
	88
	89	br = p->br;
	90	if (p->state == BR_STATE_DISABLED \|\|
	91	br_is_designated_port(p))
	92	return 0;
	93
	94	if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
	95	return 0;
	96
	97	if (!root_port)
	98	return 1;
	99
	100	rp = br_get_port(br, root_port);
	101
	102	t = memcmp(&p->designated_root, &rp->designated_root, 8);
	103	if (t < 0)
	104	return 1;
	105	else if (t > 0)
	106	return 0;
	107
	108	if (p->designated_cost + p->path_cost <
	109	rp->designated_cost + rp->path_cost)
	110	return 1;
	111	else if (p->designated_cost + p->path_cost >
	112	rp->designated_cost + rp->path_cost)
	113	return 0;
	114
	115	t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
	116	if (t < 0)
	117	return 1;
	118	else if (t > 0)
	119	return 0;
	120
	121	if (p->designated_port < rp->designated_port)
	122	return 1;
	123	else if (p->designated_port > rp->designated_port)
	124	return 0;
	125
	126	if (p->port_id < rp->port_id)
	127	return 1;
	128
	129	return 0;
	130	}
	131
1007dd1a	132	static void br_root_port_block(const struct net_bridge *br,
	133	struct net_bridge_port *p)
	134	{
	135
	136	br_notice(br, "port %u(%s) tried to become root port (blocked)",
	137	(unsigned int) p->port_no, p->dev->name);
	138
775dd692	139	br_set_state(p, BR_STATE_LISTENING);
92899063	140	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
1007dd1a	141
	142	if (br->forward_delay > 0)
	143	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
	144	}
	145
1da177e4 LT	146	/* called under bridge lock */
	147	static void br_root_selection(struct net_bridge *br)
	148	{
	149	struct net_bridge_port *p;
	150	u16 root_port = 0;
	151
	152	list_for_each_entry(p, &br->port_list, list) {
1007dd1a	153	if (!br_should_become_root_port(p, root_port))
	154	continue;
	155
	156	if (p->flags & BR_ROOT_BLOCK)
	157	br_root_port_block(br, p);
	158	else
1da177e4	159	root_port = p->port_no;
1da177e4 LT	160	}
	161
	162	br->root_port = root_port;
	163
	164	if (!root_port) {
	165	br->designated_root = br->bridge_id;
	166	br->root_path_cost = 0;
	167	} else {
	168	p = br_get_port(br, root_port);
	169	br->designated_root = p->designated_root;
	170	br->root_path_cost = p->designated_cost + p->path_cost;
	171	}
	172	}
	173
	174	/* called under bridge lock */
	175	void br_become_root_bridge(struct net_bridge *br)
	176	{
	177	br->max_age = br->bridge_max_age;
	178	br->hello_time = br->bridge_hello_time;
	179	br->forward_delay = br->bridge_forward_delay;
	180	br_topology_change_detection(br);
	181	del_timer(&br->tcn_timer);
	182
	183	if (br->dev->flags & IFF_UP) {
	184	br_config_bpdu_generation(br);
	185	mod_timer(&br->hello_timer, jiffies + br->hello_time);
	186	}
	187	}
	188
	189	/* called under bridge lock */
	190	void br_transmit_config(struct net_bridge_port *p)
	191	{
	192	struct br_config_bpdu bpdu;
	193	struct net_bridge *br;
	194
1da177e4 LT	195	if (timer_pending(&p->hold_timer)) {
	196	p->config_pending = 1;
	197	return;
	198	}
	199
	200	br = p->br;
	201
	202	bpdu.topology_change = br->topology_change;
	203	bpdu.topology_change_ack = p->topology_change_ack;
	204	bpdu.root = br->designated_root;
	205	bpdu.root_path_cost = br->root_path_cost;
	206	bpdu.bridge_id = br->bridge_id;
	207	bpdu.port_id = p->port_id;
	208	if (br_is_root_bridge(br))
	209	bpdu.message_age = 0;
	210	else {
	211	struct net_bridge_port *root
	212	= br_get_port(br, br->root_port);
0c03150e	213	bpdu.message_age = (jiffies - root->designated_age)
1da177e4 LT	214	+ MESSAGE_AGE_INCR;
	215	}
	216	bpdu.max_age = br->max_age;
	217	bpdu.hello_time = br->hello_time;
	218	bpdu.forward_delay = br->forward_delay;
	219
	220	if (bpdu.message_age < br->max_age) {
	221	br_send_config_bpdu(p, &bpdu);
	222	p->topology_change_ack = 0;
	223	p->config_pending = 0;
76b91c32 NA	224	if (p->br->stp_enabled == BR_KERNEL_STP)
	225	mod_timer(&p->hold_timer,
	226	round_jiffies(jiffies + BR_HOLD_TIME));
1da177e4 LT	227	}
	228	}
	229
	230	/* called under bridge lock */
160d73b8	231	static void br_record_config_information(struct net_bridge_port *p,
160d73b8	232	const struct br_config_bpdu *bpdu)
1da177e4 LT	233	{
	234	p->designated_root = bpdu->root;
	235	p->designated_cost = bpdu->root_path_cost;
	236	p->designated_bridge = bpdu->bridge_id;
	237	p->designated_port = bpdu->port_id;
709e1b5c	238	p->designated_age = jiffies - bpdu->message_age;
1da177e4	239
9d6f229f	240	mod_timer(&p->message_age_timer, jiffies
9a062013	241	+ (bpdu->max_age - bpdu->message_age));
1da177e4 LT	242	}
	243
	244	/* called under bridge lock */
160d73b8	245	static void br_record_config_timeout_values(struct net_bridge *br,
1da177e4 LT	246	const struct br_config_bpdu *bpdu)
	247	{
	248	br->max_age = bpdu->max_age;
	249	br->hello_time = bpdu->hello_time;
	250	br->forward_delay = bpdu->forward_delay;
8384b5f5	251	__br_set_topology_change(br, bpdu->topology_change);
1da177e4 LT	252	}
	253
	254	/* called under bridge lock */
	255	void br_transmit_tcn(struct net_bridge *br)
	256	{
91bc033c	257	struct net_bridge_port *p;
	258
	259	p = br_get_port(br, br->root_port);
	260	if (p)
	261	br_send_tcn_bpdu(p);
	262	else
	263	br_notice(br, "root port %u not found for topology notice\n",
	264	br->root_port);
1da177e4 LT	265	}
	266
	267	/* called under bridge lock */
	268	static int br_should_become_designated_port(const struct net_bridge_port *p)
	269	{
	270	struct net_bridge *br;
	271	int t;
	272
	273	br = p->br;
	274	if (br_is_designated_port(p))
	275	return 1;
	276
	277	if (memcmp(&p->designated_root, &br->designated_root, 8))
	278	return 1;
	279
	280	if (br->root_path_cost < p->designated_cost)
	281	return 1;
	282	else if (br->root_path_cost > p->designated_cost)
	283	return 0;
	284
	285	t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
	286	if (t < 0)
	287	return 1;
	288	else if (t > 0)
	289	return 0;
	290
	291	if (p->port_id < p->designated_port)
	292	return 1;
	293
	294	return 0;
	295	}
	296
	297	/* called under bridge lock */
	298	static void br_designated_port_selection(struct net_bridge *br)
	299	{
	300	struct net_bridge_port *p;
	301
	302	list_for_each_entry(p, &br->port_list, list) {
	303	if (p->state != BR_STATE_DISABLED &&
	304	br_should_become_designated_port(p))
	305	br_become_designated_port(p);
	306
	307	}
	308	}
	309
	310	/* called under bridge lock */
160d73b8	311	static int br_supersedes_port_info(const struct net_bridge_port *p,
160d73b8	312	const struct br_config_bpdu *bpdu)
1da177e4 LT	313	{
	314	int t;
	315
	316	t = memcmp(&bpdu->root, &p->designated_root, 8);
	317	if (t < 0)
	318	return 1;
	319	else if (t > 0)
	320	return 0;
	321
	322	if (bpdu->root_path_cost < p->designated_cost)
	323	return 1;
	324	else if (bpdu->root_path_cost > p->designated_cost)
	325	return 0;
	326
	327	t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
	328	if (t < 0)
	329	return 1;
	330	else if (t > 0)
	331	return 0;
	332
	333	if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
	334	return 1;
	335
	336	if (bpdu->port_id <= p->designated_port)
	337	return 1;
	338
	339	return 0;
	340	}
	341
	342	/* called under bridge lock */
160d73b8	343	static void br_topology_change_acknowledged(struct net_bridge *br)
1da177e4 LT	344	{
	345	br->topology_change_detected = 0;
	346	del_timer(&br->tcn_timer);
	347	}
	348
	349	/* called under bridge lock */
	350	void br_topology_change_detection(struct net_bridge *br)
	351	{
	352	int isroot = br_is_root_bridge(br);
	353
4f0611af SH	354	if (br->stp_enabled != BR_KERNEL_STP)
	355	return;
	356
28a16c97	357	br_info(br, "topology change detected, %s\n",
1da177e4 LT	358	isroot ? "propagating" : "sending tcn bpdu");
	359
	360	if (isroot) {
8384b5f5	361	__br_set_topology_change(br, 1);
1da177e4 LT	362	mod_timer(&br->topology_change_timer, jiffies
	363	+ br->bridge_forward_delay + br->bridge_max_age);
	364	} else if (!br->topology_change_detected) {
	365	br_transmit_tcn(br);
	366	mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
	367	}
	368
	369	br->topology_change_detected = 1;
	370	}
	371
	372	/* called under bridge lock */
	373	void br_config_bpdu_generation(struct net_bridge *br)
	374	{
	375	struct net_bridge_port *p;
	376
	377	list_for_each_entry(p, &br->port_list, list) {
	378	if (p->state != BR_STATE_DISABLED &&
	379	br_is_designated_port(p))
	380	br_transmit_config(p);
	381	}
	382	}
	383
	384	/* called under bridge lock */
160d73b8	385	static void br_reply(struct net_bridge_port *p)
1da177e4 LT	386	{
	387	br_transmit_config(p);
	388	}
	389
	390	/* called under bridge lock */
	391	void br_configuration_update(struct net_bridge *br)
	392	{
	393	br_root_selection(br);
	394	br_designated_port_selection(br);
	395	}
	396
	397	/* called under bridge lock */
	398	void br_become_designated_port(struct net_bridge_port *p)
	399	{
	400	struct net_bridge *br;
	401
	402	br = p->br;
	403	p->designated_root = br->designated_root;
	404	p->designated_cost = br->root_path_cost;
	405	p->designated_bridge = br->bridge_id;
	406	p->designated_port = p->port_id;
	407	}
	408
	409
	410	/* called under bridge lock */
	411	static void br_make_blocking(struct net_bridge_port *p)
	412	{
	413	if (p->state != BR_STATE_DISABLED &&
	414	p->state != BR_STATE_BLOCKING) {
	415	if (p->state == BR_STATE_FORWARDING \|\|
	416	p->state == BR_STATE_LEARNING)
	417	br_topology_change_detection(p->br);
	418
775dd692	419	br_set_state(p, BR_STATE_BLOCKING);
92899063	420	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
4ecb961c	421
1da177e4 LT	422	del_timer(&p->forward_delay_timer);
	423	}
	424	}
	425
	426	/* called under bridge lock */
	427	static void br_make_forwarding(struct net_bridge_port *p)
	428	{
ef647f13	429	struct net_bridge *br = p->br;
9cde0708	430
ef647f13 SH	431	if (p->state != BR_STATE_BLOCKING)
	432	return;
	433
a461c029	434	if (br->stp_enabled == BR_NO_STP \|\| br->forward_delay == 0) {
775dd692	435	br_set_state(p, BR_STATE_FORWARDING);
ef647f13 SH	436	br_topology_change_detection(br);
ef647f13 SH	437	del_timer(&p->forward_delay_timer);
160d73b8	438	} else if (br->stp_enabled == BR_KERNEL_STP)
775dd692	439	br_set_state(p, BR_STATE_LISTENING);
ef647f13	440	else
775dd692	441	br_set_state(p, BR_STATE_LEARNING);
ef647f13	442
92899063	443	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
ef647f13 SH	444
	445	if (br->forward_delay != 0)
	446	mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
1da177e4 LT	447	}
	448
	449	/* called under bridge lock */
	450	void br_port_state_selection(struct net_bridge *br)
	451	{
	452	struct net_bridge_port *p;
1faa4356	453	unsigned int liveports = 0;
1da177e4 LT	454
1da177e4 LT	455	list_for_each_entry(p, &br->port_list, list) {
1faa4356	456	if (p->state == BR_STATE_DISABLED)
	457	continue;
	458
b03b6dd5 VD	459	/* Don't change port states if userspace is handling STP */
	460	if (br->stp_enabled != BR_USER_STP) {
	461	if (p->port_no == br->root_port) {
	462	p->config_pending = 0;
	463	p->topology_change_ack = 0;
	464	br_make_forwarding(p);
	465	} else if (br_is_designated_port(p)) {
	466	del_timer(&p->message_age_timer);
	467	br_make_forwarding(p);
	468	} else {
	469	p->config_pending = 0;
	470	p->topology_change_ack = 0;
	471	br_make_blocking(p);
	472	}
1da177e4 LT	473	}
1da177e4 LT	474
7ce42de1 NA	475	if (p->state != BR_STATE_BLOCKING)
7ce42de1 NA	476	br_multicast_enable_port(p);
9aa66382 NA	477	/* Multicast is not disabled for the port when it goes in
	478	* blocking state because the timers will expire and stop by
	479	* themselves without sending more queries.
	480	*/
1faa4356	481	if (p->state == BR_STATE_FORWARDING)
1faa4356	482	++liveports;
1da177e4	483	}
1faa4356	484
	485	if (liveports == 0)
	486	netif_carrier_off(br->dev);
	487	else
	488	netif_carrier_on(br->dev);
1da177e4 LT	489	}
	490
	491	/* called under bridge lock */
160d73b8	492	static void br_topology_change_acknowledge(struct net_bridge_port *p)
1da177e4 LT	493	{
	494	p->topology_change_ack = 1;
	495	br_transmit_config(p);
	496	}
	497
	498	/* called under bridge lock */
160d73b8	499	void br_received_config_bpdu(struct net_bridge_port *p,
160d73b8	500	const struct br_config_bpdu *bpdu)
1da177e4 LT	501	{
	502	struct net_bridge *br;
	503	int was_root;
9d6f229f	504
de179966 VD	505	p->stp_xstats.rx_bpdu++;
de179966 VD	506
1da177e4 LT	507	br = p->br;
	508	was_root = br_is_root_bridge(br);
	509
	510	if (br_supersedes_port_info(p, bpdu)) {
	511	br_record_config_information(p, bpdu);
	512	br_configuration_update(br);
	513	br_port_state_selection(br);
	514
	515	if (!br_is_root_bridge(br) && was_root) {
	516	del_timer(&br->hello_timer);
	517	if (br->topology_change_detected) {
	518	del_timer(&br->topology_change_timer);
	519	br_transmit_tcn(br);
	520
9d6f229f	521	mod_timer(&br->tcn_timer,
1da177e4 LT	522	jiffies + br->bridge_hello_time);
	523	}
	524	}
	525
	526	if (p->port_no == br->root_port) {
	527	br_record_config_timeout_values(br, bpdu);
	528	br_config_bpdu_generation(br);
	529	if (bpdu->topology_change_ack)
	530	br_topology_change_acknowledged(br);
	531	}
9d6f229f YH	532	} else if (br_is_designated_port(p)) {
9d6f229f YH	533	br_reply(p);
1da177e4 LT	534	}
	535	}
	536
	537	/* called under bridge lock */
	538	void br_received_tcn_bpdu(struct net_bridge_port *p)
	539	{
de179966 VD	540	p->stp_xstats.rx_tcn++;
de179966 VD	541
1da177e4	542	if (br_is_designated_port(p)) {
28a16c97	543	br_info(p->br, "port %u(%s) received tcn bpdu\n",
95c96174	544	(unsigned int) p->port_no, p->dev->name);
1da177e4 LT	545
	546	br_topology_change_detection(p->br);
	547	br_topology_change_acknowledge(p);
	548	}
	549	}
14f98f25	550
	551	/* Change bridge STP parameter */
	552	int br_set_hello_time(struct net_bridge *br, unsigned long val)
	553	{
	554	unsigned long t = clock_t_to_jiffies(val);
	555
	556	if (t < BR_MIN_HELLO_TIME \|\| t > BR_MAX_HELLO_TIME)
	557	return -ERANGE;
	558
	559	spin_lock_bh(&br->lock);
	560	br->bridge_hello_time = t;
	561	if (br_is_root_bridge(br))
	562	br->hello_time = br->bridge_hello_time;
	563	spin_unlock_bh(&br->lock);
	564	return 0;
	565	}
	566
	567	int br_set_max_age(struct net_bridge *br, unsigned long val)
	568	{
	569	unsigned long t = clock_t_to_jiffies(val);
	570
	571	if (t < BR_MIN_MAX_AGE \|\| t > BR_MAX_MAX_AGE)
	572	return -ERANGE;
	573
	574	spin_lock_bh(&br->lock);
	575	br->bridge_max_age = t;
	576	if (br_is_root_bridge(br))
	577	br->max_age = br->bridge_max_age;
	578	spin_unlock_bh(&br->lock);
	579	return 0;
	580
	581	}
	582
82dd4332 VD	583	/* called under bridge lock */
	584	int __set_ageing_time(struct net_device *dev, unsigned long t)
	585	{
	586	struct switchdev_attr attr = {
	587	.orig_dev = dev,
	588	.id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
	589	.flags = SWITCHDEV_F_SKIP_EOPNOTSUPP \| SWITCHDEV_F_DEFER,
	590	.u.ageing_time = jiffies_to_clock_t(t),
	591	};
	592	int err;
	593
dcbdf135	594	err = switchdev_port_attr_set(dev, &attr, NULL);
82dd4332 VD	595	if (err && err != -EOPNOTSUPP)
	596	return err;
	597
	598	return 0;
	599	}
	600
4c656c13 SH	601	/* Set time interval that dynamic forwarding entries live
	602	* For pure software bridge, allow values outside the 802.1
	603	* standard specification for special cases:
efb5b338 MD	604	* 0 - entry never ages (all permanent)
efb5b338 MD	605	* 1 - entry disappears (no persistence)
4c656c13 SH	606	*
	607	* Offloaded switch entries maybe more restrictive
	608	*/
9e0b27fe	609	int br_set_ageing_time(struct net_bridge *br, clock_t ageing_time)
c62987bb	610	{
c62987bb SF	611	unsigned long t = clock_t_to_jiffies(ageing_time);
	612	int err;
	613
82dd4332 VD	614	err = __set_ageing_time(br->dev, t);
82dd4332 VD	615	if (err)
c62987bb SF	616	return err;
c62987bb SF	617
34d8acd8 VD	618	spin_lock_bh(&br->lock);
34d8acd8 VD	619	br->bridge_ageing_time = t;
c62987bb	620	br->ageing_time = t;
34d8acd8 VD	621	spin_unlock_bh(&br->lock);
34d8acd8 VD	622
f7cdee8a	623	mod_delayed_work(system_long_wq, &br->gc_work, 0);
c62987bb SF	624
	625	return 0;
	626	}
	627
8384b5f5 VD	628	/* called under bridge lock */
	629	void __br_set_topology_change(struct net_bridge *br, unsigned char val)
	630	{
34d8acd8 VD	631	unsigned long t;
	632	int err;
	633
	634	if (br->stp_enabled == BR_KERNEL_STP && br->topology_change != val) {
	635	/* On topology change, set the bridge ageing time to twice the
	636	* forward delay. Otherwise, restore its default ageing time.
	637	*/
	638
	639	if (val) {
	640	t = 2 * br->forward_delay;
	641	br_debug(br, "decreasing ageing time to %lu\n", t);
	642	} else {
	643	t = br->bridge_ageing_time;
	644	br_debug(br, "restoring ageing time to %lu\n", t);
	645	}
	646
	647	err = __set_ageing_time(br->dev, t);
	648	if (err)
	649	br_warn(br, "error offloading ageing time\n");
	650	else
	651	br->ageing_time = t;
	652	}
	653
8384b5f5 VD	654	br->topology_change = val;
	655	}
	656
be4f154d HX	657	void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
	658	{
	659	br->bridge_forward_delay = t;
	660	if (br_is_root_bridge(br))
	661	br->forward_delay = br->bridge_forward_delay;
	662	}
	663
14f98f25	664	int br_set_forward_delay(struct net_bridge *br, unsigned long val)
	665	{
	666	unsigned long t = clock_t_to_jiffies(val);
8a921265	667	int err = -ERANGE;
14f98f25	668
34c2d9fb	669	spin_lock_bh(&br->lock);
8a921265 VY	670	if (br->stp_enabled != BR_NO_STP &&
	671	(t < BR_MIN_FORWARD_DELAY \|\| t > BR_MAX_FORWARD_DELAY))
	672	goto unlock;
	673
be4f154d	674	__br_set_forward_delay(br, t);
8a921265 VY	675	err = 0;
	676
	677	unlock:
14f98f25	678	spin_unlock_bh(&br->lock);
8a921265	679	return err;
14f98f25	680	}