linux/net/bridge/br_stp.c
Nikolay Aleksandrov 76b91c32dd bridge: stp: when using userspace stp stop kernel hello and hold timers
These should be handled only by the respective STP which is in control.
They become problematic for devices with limited resources with many
ports because the hold_timer is per port and fires each second and the
hello timer fires each 2 seconds even though it's global. While in
user-space STP mode these timers are completely unnecessary so it's better
to keep them off.
Also ensure that when the bridge is up these timers are started only when
running with kernel STP.

Signed-off-by: Satish Ashok <sashok@cumulusnetworks.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-28 23:33:20 -07:00

593 lines
14 KiB
C

/*
* Spanning tree protocol; generic parts
* Linux ethernet bridge
*
* Authors:
* Lennert Buytenhek <buytenh@gnu.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/rculist.h>
#include <net/switchdev.h>
#include "br_private.h"
#include "br_private_stp.h"
/* since time values in bpdu are in jiffies and then scaled (1/256)
* before sending, make sure that is at least one STP tick.
*/
#define MESSAGE_AGE_INCR ((HZ / 256) + 1)
static const char *const br_port_state_names[] = {
[BR_STATE_DISABLED] = "disabled",
[BR_STATE_LISTENING] = "listening",
[BR_STATE_LEARNING] = "learning",
[BR_STATE_FORWARDING] = "forwarding",
[BR_STATE_BLOCKING] = "blocking",
};
void br_log_state(const struct net_bridge_port *p)
{
br_info(p->br, "port %u(%s) entered %s state\n",
(unsigned int) p->port_no, p->dev->name,
br_port_state_names[p->state]);
}
void br_set_state(struct net_bridge_port *p, unsigned int state)
{
struct switchdev_attr attr = {
.id = SWITCHDEV_ATTR_PORT_STP_STATE,
.u.stp_state = state,
};
int err;
p->state = state;
err = switchdev_port_attr_set(p->dev, &attr);
if (err && err != -EOPNOTSUPP)
br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
(unsigned int) p->port_no, p->dev->name);
}
/* called under bridge lock */
struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no)
{
struct net_bridge_port *p;
list_for_each_entry_rcu(p, &br->port_list, list) {
if (p->port_no == port_no)
return p;
}
return NULL;
}
/* called under bridge lock */
static int br_should_become_root_port(const struct net_bridge_port *p,
u16 root_port)
{
struct net_bridge *br;
struct net_bridge_port *rp;
int t;
br = p->br;
if (p->state == BR_STATE_DISABLED ||
br_is_designated_port(p))
return 0;
if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
return 0;
if (!root_port)
return 1;
rp = br_get_port(br, root_port);
t = memcmp(&p->designated_root, &rp->designated_root, 8);
if (t < 0)
return 1;
else if (t > 0)
return 0;
if (p->designated_cost + p->path_cost <
rp->designated_cost + rp->path_cost)
return 1;
else if (p->designated_cost + p->path_cost >
rp->designated_cost + rp->path_cost)
return 0;
t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
if (t < 0)
return 1;
else if (t > 0)
return 0;
if (p->designated_port < rp->designated_port)
return 1;
else if (p->designated_port > rp->designated_port)
return 0;
if (p->port_id < rp->port_id)
return 1;
return 0;
}
static void br_root_port_block(const struct net_bridge *br,
struct net_bridge_port *p)
{
br_notice(br, "port %u(%s) tried to become root port (blocked)",
(unsigned int) p->port_no, p->dev->name);
br_set_state(p, BR_STATE_LISTENING);
br_log_state(p);
br_ifinfo_notify(RTM_NEWLINK, p);
if (br->forward_delay > 0)
mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
}
/* called under bridge lock */
static void br_root_selection(struct net_bridge *br)
{
struct net_bridge_port *p;
u16 root_port = 0;
list_for_each_entry(p, &br->port_list, list) {
if (!br_should_become_root_port(p, root_port))
continue;
if (p->flags & BR_ROOT_BLOCK)
br_root_port_block(br, p);
else
root_port = p->port_no;
}
br->root_port = root_port;
if (!root_port) {
br->designated_root = br->bridge_id;
br->root_path_cost = 0;
} else {
p = br_get_port(br, root_port);
br->designated_root = p->designated_root;
br->root_path_cost = p->designated_cost + p->path_cost;
}
}
/* called under bridge lock */
void br_become_root_bridge(struct net_bridge *br)
{
br->max_age = br->bridge_max_age;
br->hello_time = br->bridge_hello_time;
br->forward_delay = br->bridge_forward_delay;
br_topology_change_detection(br);
del_timer(&br->tcn_timer);
if (br->dev->flags & IFF_UP) {
br_config_bpdu_generation(br);
mod_timer(&br->hello_timer, jiffies + br->hello_time);
}
}
/* called under bridge lock */
void br_transmit_config(struct net_bridge_port *p)
{
struct br_config_bpdu bpdu;
struct net_bridge *br;
if (timer_pending(&p->hold_timer)) {
p->config_pending = 1;
return;
}
br = p->br;
bpdu.topology_change = br->topology_change;
bpdu.topology_change_ack = p->topology_change_ack;
bpdu.root = br->designated_root;
bpdu.root_path_cost = br->root_path_cost;
bpdu.bridge_id = br->bridge_id;
bpdu.port_id = p->port_id;
if (br_is_root_bridge(br))
bpdu.message_age = 0;
else {
struct net_bridge_port *root
= br_get_port(br, br->root_port);
bpdu.message_age = (jiffies - root->designated_age)
+ MESSAGE_AGE_INCR;
}
bpdu.max_age = br->max_age;
bpdu.hello_time = br->hello_time;
bpdu.forward_delay = br->forward_delay;
if (bpdu.message_age < br->max_age) {
br_send_config_bpdu(p, &bpdu);
p->topology_change_ack = 0;
p->config_pending = 0;
if (p->br->stp_enabled == BR_KERNEL_STP)
mod_timer(&p->hold_timer,
round_jiffies(jiffies + BR_HOLD_TIME));
}
}
/* called under bridge lock */
static void br_record_config_information(struct net_bridge_port *p,
const struct br_config_bpdu *bpdu)
{
p->designated_root = bpdu->root;
p->designated_cost = bpdu->root_path_cost;
p->designated_bridge = bpdu->bridge_id;
p->designated_port = bpdu->port_id;
p->designated_age = jiffies - bpdu->message_age;
mod_timer(&p->message_age_timer, jiffies
+ (bpdu->max_age - bpdu->message_age));
}
/* called under bridge lock */
static void br_record_config_timeout_values(struct net_bridge *br,
const struct br_config_bpdu *bpdu)
{
br->max_age = bpdu->max_age;
br->hello_time = bpdu->hello_time;
br->forward_delay = bpdu->forward_delay;
br->topology_change = bpdu->topology_change;
}
/* called under bridge lock */
void br_transmit_tcn(struct net_bridge *br)
{
struct net_bridge_port *p;
p = br_get_port(br, br->root_port);
if (p)
br_send_tcn_bpdu(p);
else
br_notice(br, "root port %u not found for topology notice\n",
br->root_port);
}
/* called under bridge lock */
static int br_should_become_designated_port(const struct net_bridge_port *p)
{
struct net_bridge *br;
int t;
br = p->br;
if (br_is_designated_port(p))
return 1;
if (memcmp(&p->designated_root, &br->designated_root, 8))
return 1;
if (br->root_path_cost < p->designated_cost)
return 1;
else if (br->root_path_cost > p->designated_cost)
return 0;
t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
if (t < 0)
return 1;
else if (t > 0)
return 0;
if (p->port_id < p->designated_port)
return 1;
return 0;
}
/* called under bridge lock */
static void br_designated_port_selection(struct net_bridge *br)
{
struct net_bridge_port *p;
list_for_each_entry(p, &br->port_list, list) {
if (p->state != BR_STATE_DISABLED &&
br_should_become_designated_port(p))
br_become_designated_port(p);
}
}
/* called under bridge lock */
static int br_supersedes_port_info(const struct net_bridge_port *p,
const struct br_config_bpdu *bpdu)
{
int t;
t = memcmp(&bpdu->root, &p->designated_root, 8);
if (t < 0)
return 1;
else if (t > 0)
return 0;
if (bpdu->root_path_cost < p->designated_cost)
return 1;
else if (bpdu->root_path_cost > p->designated_cost)
return 0;
t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
if (t < 0)
return 1;
else if (t > 0)
return 0;
if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
return 1;
if (bpdu->port_id <= p->designated_port)
return 1;
return 0;
}
/* called under bridge lock */
static void br_topology_change_acknowledged(struct net_bridge *br)
{
br->topology_change_detected = 0;
del_timer(&br->tcn_timer);
}
/* called under bridge lock */
void br_topology_change_detection(struct net_bridge *br)
{
int isroot = br_is_root_bridge(br);
if (br->stp_enabled != BR_KERNEL_STP)
return;
br_info(br, "topology change detected, %s\n",
isroot ? "propagating" : "sending tcn bpdu");
if (isroot) {
br->topology_change = 1;
mod_timer(&br->topology_change_timer, jiffies
+ br->bridge_forward_delay + br->bridge_max_age);
} else if (!br->topology_change_detected) {
br_transmit_tcn(br);
mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
}
br->topology_change_detected = 1;
}
/* called under bridge lock */
void br_config_bpdu_generation(struct net_bridge *br)
{
struct net_bridge_port *p;
list_for_each_entry(p, &br->port_list, list) {
if (p->state != BR_STATE_DISABLED &&
br_is_designated_port(p))
br_transmit_config(p);
}
}
/* called under bridge lock */
static void br_reply(struct net_bridge_port *p)
{
br_transmit_config(p);
}
/* called under bridge lock */
void br_configuration_update(struct net_bridge *br)
{
br_root_selection(br);
br_designated_port_selection(br);
}
/* called under bridge lock */
void br_become_designated_port(struct net_bridge_port *p)
{
struct net_bridge *br;
br = p->br;
p->designated_root = br->designated_root;
p->designated_cost = br->root_path_cost;
p->designated_bridge = br->bridge_id;
p->designated_port = p->port_id;
}
/* called under bridge lock */
static void br_make_blocking(struct net_bridge_port *p)
{
if (p->state != BR_STATE_DISABLED &&
p->state != BR_STATE_BLOCKING) {
if (p->state == BR_STATE_FORWARDING ||
p->state == BR_STATE_LEARNING)
br_topology_change_detection(p->br);
br_set_state(p, BR_STATE_BLOCKING);
br_log_state(p);
br_ifinfo_notify(RTM_NEWLINK, p);
del_timer(&p->forward_delay_timer);
}
}
/* called under bridge lock */
static void br_make_forwarding(struct net_bridge_port *p)
{
struct net_bridge *br = p->br;
if (p->state != BR_STATE_BLOCKING)
return;
if (br->stp_enabled == BR_NO_STP || br->forward_delay == 0) {
br_set_state(p, BR_STATE_FORWARDING);
br_topology_change_detection(br);
del_timer(&p->forward_delay_timer);
} else if (br->stp_enabled == BR_KERNEL_STP)
br_set_state(p, BR_STATE_LISTENING);
else
br_set_state(p, BR_STATE_LEARNING);
br_log_state(p);
br_ifinfo_notify(RTM_NEWLINK, p);
if (br->forward_delay != 0)
mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
}
/* called under bridge lock */
void br_port_state_selection(struct net_bridge *br)
{
struct net_bridge_port *p;
unsigned int liveports = 0;
list_for_each_entry(p, &br->port_list, list) {
if (p->state == BR_STATE_DISABLED)
continue;
/* Don't change port states if userspace is handling STP */
if (br->stp_enabled != BR_USER_STP) {
if (p->port_no == br->root_port) {
p->config_pending = 0;
p->topology_change_ack = 0;
br_make_forwarding(p);
} else if (br_is_designated_port(p)) {
del_timer(&p->message_age_timer);
br_make_forwarding(p);
} else {
p->config_pending = 0;
p->topology_change_ack = 0;
br_make_blocking(p);
}
}
if (p->state != BR_STATE_BLOCKING)
br_multicast_enable_port(p);
/* Multicast is not disabled for the port when it goes in
* blocking state because the timers will expire and stop by
* themselves without sending more queries.
*/
if (p->state == BR_STATE_FORWARDING)
++liveports;
}
if (liveports == 0)
netif_carrier_off(br->dev);
else
netif_carrier_on(br->dev);
}
/* called under bridge lock */
static void br_topology_change_acknowledge(struct net_bridge_port *p)
{
p->topology_change_ack = 1;
br_transmit_config(p);
}
/* called under bridge lock */
void br_received_config_bpdu(struct net_bridge_port *p,
const struct br_config_bpdu *bpdu)
{
struct net_bridge *br;
int was_root;
br = p->br;
was_root = br_is_root_bridge(br);
if (br_supersedes_port_info(p, bpdu)) {
br_record_config_information(p, bpdu);
br_configuration_update(br);
br_port_state_selection(br);
if (!br_is_root_bridge(br) && was_root) {
del_timer(&br->hello_timer);
if (br->topology_change_detected) {
del_timer(&br->topology_change_timer);
br_transmit_tcn(br);
mod_timer(&br->tcn_timer,
jiffies + br->bridge_hello_time);
}
}
if (p->port_no == br->root_port) {
br_record_config_timeout_values(br, bpdu);
br_config_bpdu_generation(br);
if (bpdu->topology_change_ack)
br_topology_change_acknowledged(br);
}
} else if (br_is_designated_port(p)) {
br_reply(p);
}
}
/* called under bridge lock */
void br_received_tcn_bpdu(struct net_bridge_port *p)
{
if (br_is_designated_port(p)) {
br_info(p->br, "port %u(%s) received tcn bpdu\n",
(unsigned int) p->port_no, p->dev->name);
br_topology_change_detection(p->br);
br_topology_change_acknowledge(p);
}
}
/* Change bridge STP parameter */
int br_set_hello_time(struct net_bridge *br, unsigned long val)
{
unsigned long t = clock_t_to_jiffies(val);
if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
return -ERANGE;
spin_lock_bh(&br->lock);
br->bridge_hello_time = t;
if (br_is_root_bridge(br))
br->hello_time = br->bridge_hello_time;
spin_unlock_bh(&br->lock);
return 0;
}
int br_set_max_age(struct net_bridge *br, unsigned long val)
{
unsigned long t = clock_t_to_jiffies(val);
if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
return -ERANGE;
spin_lock_bh(&br->lock);
br->bridge_max_age = t;
if (br_is_root_bridge(br))
br->max_age = br->bridge_max_age;
spin_unlock_bh(&br->lock);
return 0;
}
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;
}