br_stp_timer.c

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/*
 *  Spanning tree protocol; timer-related code
 *  Linux ethernet bridge
 *
 *  Authors:
 *  Lennert Buytenhek       <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/times.h>

#include "br_private.h"
#include "br_private_stp.h"

/* called under bridge lock */
static int br_is_designated_for_some_port(const struct net_bridge *br)
{
    struct net_bridge_port *p;

    list_for_each_entry(p, &br->port_list, list) {
        if (p->state != BR_STATE_DISABLED &&
            !memcmp(&p->designated_bridge, &br->bridge_id, 8))
            return 1;
    }

    return 0;
}

static void br_hello_timer_expired(unsigned long arg)
{
    struct net_bridge *br = (struct net_bridge *)arg;

    br_debug(br, "hello timer expired\n");
    spin_lock(&br->lock);
    if (br->dev->flags & IFF_UP) {
        br_config_bpdu_generation(br);

        mod_timer(&br->hello_timer, round_jiffies(jiffies + br->hello_time));
    }
    spin_unlock(&br->lock);
}

static void br_message_age_timer_expired(unsigned long arg)
{
    struct net_bridge_port *p = (struct net_bridge_port *) arg;
    struct net_bridge *br = p->br;
    const bridge_id *id = &p->designated_bridge;
    int was_root;

    if (p->state == BR_STATE_DISABLED)
        return;

    br_info(br, "port %u(%s) neighbor %.2x%.2x.%pM lost\n",
        (unsigned int) p->port_no, p->dev->name,
        id->prio[0], id->prio[1], &id->addr);

    /*
     * According to the spec, the message age timer cannot be
     * running when we are the root bridge. So..  this was_root
     * check is redundant. I'm leaving it in for now, though.
     */
    spin_lock(&br->lock);
    if (p->state == BR_STATE_DISABLED)
        goto unlock;
    was_root = br_is_root_bridge(br);

    br_become_designated_port(p);
    br_configuration_update(br);
    br_port_state_selection(br);
    if (br_is_root_bridge(br) && !was_root)
        br_become_root_bridge(br);
 unlock:
    spin_unlock(&br->lock);
}

static void br_forward_delay_timer_expired(unsigned long arg)
{
    struct net_bridge_port *p = (struct net_bridge_port *) arg;
    struct net_bridge *br = p->br;

    br_debug(br, "port %u(%s) forward delay timer\n",
         (unsigned int) p->port_no, p->dev->name);
    spin_lock(&br->lock);
    if (p->state == BR_STATE_LISTENING) {
        p->state = BR_STATE_LEARNING;
        mod_timer(&p->forward_delay_timer,
              jiffies + br->forward_delay);
    } else if (p->state == BR_STATE_LEARNING) {
        p->state = BR_STATE_FORWARDING;
        if (br_is_designated_for_some_port(br))
            br_topology_change_detection(br);
        netif_carrier_on(br->dev);
    }
    br_log_state(p);
    br_ifinfo_notify(RTM_NEWLINK, p);
    spin_unlock(&br->lock);
}

static void br_tcn_timer_expired(unsigned long arg)
{
    struct net_bridge *br = (struct net_bridge *) arg;

    br_debug(br, "tcn timer expired\n");
    spin_lock(&br->lock);
    if (br->dev->flags & IFF_UP) {
        br_transmit_tcn(br);

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

static void br_topology_change_timer_expired(unsigned long arg)
{
    struct net_bridge *br = (struct net_bridge *) arg;

    br_debug(br, "topo change timer expired\n");
    spin_lock(&br->lock);
    br->topology_change_detected = 0;
    br->topology_change = 0;
    spin_unlock(&br->lock);
}

static void br_hold_timer_expired(unsigned long arg)
{
    struct net_bridge_port *p = (struct net_bridge_port *) arg;

    br_debug(p->br, "port %u(%s) hold timer expired\n",
         (unsigned int) p->port_no, p->dev->name);

    spin_lock(&p->br->lock);
    if (p->config_pending)
        br_transmit_config(p);
    spin_unlock(&p->br->lock);
}

void br_stp_timer_init(struct net_bridge *br)
{
    setup_timer(&br->hello_timer, br_hello_timer_expired,
              (unsigned long) br);

    setup_timer(&br->tcn_timer, br_tcn_timer_expired,
              (unsigned long) br);

    setup_timer(&br->topology_change_timer,
              br_topology_change_timer_expired,
              (unsigned long) br);

    setup_timer(&br->gc_timer, br_fdb_cleanup, (unsigned long) br);
}

void br_stp_port_timer_init(struct net_bridge_port *p)
{
    setup_timer(&p->message_age_timer, br_message_age_timer_expired,
              (unsigned long) p);

    setup_timer(&p->forward_delay_timer, br_forward_delay_timer_expired,
              (unsigned long) p);

    setup_timer(&p->hold_timer, br_hold_timer_expired,
              (unsigned long) p);
}

/* Report ticks left (in USER_HZ) used for API */
unsigned long br_timer_value(const struct timer_list *timer)
{
    return timer_pending(timer)
        ? jiffies_delta_to_clock_t(timer->expires - jiffies) : 0;
}