LXR linux/net/bridge/br_stp

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *      Spanning tree protocol; timer-related code
   4 *      Linux ethernet bridge
   5 *
   6 *      Authors:
   7 *      Lennert Buytenhek               <buytenh@gnu.org>
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/times.h>
  12
  13#include "br_private.h"
  14#include "br_private_stp.h"
  15
  16/* called under bridge lock */
  17static int br_is_designated_for_some_port(const struct net_bridge *br)
  18{
  19        struct net_bridge_port *p;
  20
  21        list_for_each_entry(p, &br->port_list, list) {
  22                if (p->state != BR_STATE_DISABLED &&
  23                    !memcmp(&p->designated_bridge, &br->bridge_id, 8))
  24                        return 1;
  25        }
  26
  27        return 0;
  28}
  29
  30static void br_hello_timer_expired(struct timer_list *t)
  31{
  32        struct net_bridge *br = from_timer(br, t, hello_timer);
  33
  34        br_debug(br, "hello timer expired\n");
  35        spin_lock(&br->lock);
  36        if (br->dev->flags & IFF_UP) {
  37                br_config_bpdu_generation(br);
  38
  39                if (br->stp_enabled == BR_KERNEL_STP)
  40                        mod_timer(&br->hello_timer,
  41                                  round_jiffies(jiffies + br->hello_time));
  42        }
  43        spin_unlock(&br->lock);
  44}
  45
  46static void br_message_age_timer_expired(struct timer_list *t)
  47{
  48        struct net_bridge_port *p = from_timer(p, t, message_age_timer);
  49        struct net_bridge *br = p->br;
  50        const bridge_id *id = &p->designated_bridge;
  51        int was_root;
  52
  53        if (p->state == BR_STATE_DISABLED)
  54                return;
  55
  56        br_info(br, "port %u(%s) neighbor %.2x%.2x.%pM lost\n",
  57                (unsigned int) p->port_no, p->dev->name,
  58                id->prio[0], id->prio[1], &id->addr);
  59
  60        /*
  61         * According to the spec, the message age timer cannot be
  62         * running when we are the root bridge. So..  this was_root
  63         * check is redundant. I'm leaving it in for now, though.
  64         */
  65        spin_lock(&br->lock);
  66        if (p->state == BR_STATE_DISABLED)
  67                goto unlock;
  68        was_root = br_is_root_bridge(br);
  69
  70        br_become_designated_port(p);
  71        br_configuration_update(br);
  72        br_port_state_selection(br);
  73        if (br_is_root_bridge(br) && !was_root)
  74                br_become_root_bridge(br);
  75 unlock:
  76        spin_unlock(&br->lock);
  77}
  78
  79static void br_forward_delay_timer_expired(struct timer_list *t)
  80{
  81        struct net_bridge_port *p = from_timer(p, t, forward_delay_timer);
  82        struct net_bridge *br = p->br;
  83
  84        br_debug(br, "port %u(%s) forward delay timer\n",
  85                 (unsigned int) p->port_no, p->dev->name);
  86        spin_lock(&br->lock);
  87        if (p->state == BR_STATE_LISTENING) {
  88                br_set_state(p, BR_STATE_LEARNING);
  89                mod_timer(&p->forward_delay_timer,
  90                          jiffies + br->forward_delay);
  91        } else if (p->state == BR_STATE_LEARNING) {
  92                br_set_state(p, BR_STATE_FORWARDING);
  93                if (br_is_designated_for_some_port(br))
  94                        br_topology_change_detection(br);
  95                netif_carrier_on(br->dev);
  96        }
  97        rcu_read_lock();
  98        br_ifinfo_notify(RTM_NEWLINK, NULL, p);
  99        rcu_read_unlock();
 100        spin_unlock(&br->lock);
 101}
 102
 103static void br_tcn_timer_expired(struct timer_list *t)
 104{
 105        struct net_bridge *br = from_timer(br, t, tcn_timer);
 106
 107        br_debug(br, "tcn timer expired\n");
 108        spin_lock(&br->lock);
 109        if (!br_is_root_bridge(br) && (br->dev->flags & IFF_UP)) {
 110                br_transmit_tcn(br);
 111
 112                mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
 113        }
 114        spin_unlock(&br->lock);
 115}
 116
 117static void br_topology_change_timer_expired(struct timer_list *t)
 118{
 119        struct net_bridge *br = from_timer(br, t, topology_change_timer);
 120
 121        br_debug(br, "topo change timer expired\n");
 122        spin_lock(&br->lock);
 123        br->topology_change_detected = 0;
 124        __br_set_topology_change(br, 0);
 125        spin_unlock(&br->lock);
 126}
 127
 128static void br_hold_timer_expired(struct timer_list *t)
 129{
 130        struct net_bridge_port *p = from_timer(p, t, hold_timer);
 131
 132        br_debug(p->br, "port %u(%s) hold timer expired\n",
 133                 (unsigned int) p->port_no, p->dev->name);
 134
 135        spin_lock(&p->br->lock);
 136        if (p->config_pending)
 137                br_transmit_config(p);
 138        spin_unlock(&p->br->lock);
 139}
 140
 141void br_stp_timer_init(struct net_bridge *br)
 142{
 143        timer_setup(&br->hello_timer, br_hello_timer_expired, 0);
 144        timer_setup(&br->tcn_timer, br_tcn_timer_expired, 0);
 145        timer_setup(&br->topology_change_timer,
 146                    br_topology_change_timer_expired, 0);
 147}
 148
 149void br_stp_port_timer_init(struct net_bridge_port *p)
 150{
 151        timer_setup(&p->message_age_timer, br_message_age_timer_expired, 0);
 152        timer_setup(&p->forward_delay_timer, br_forward_delay_timer_expired, 0);
 153        timer_setup(&p->hold_timer, br_hold_timer_expired, 0);
 154}
 155
 156/* Report ticks left (in USER_HZ) used for API */
 157unsigned long br_timer_value(const struct timer_list *timer)
 158{
 159        return timer_pending(timer)
 160                ? jiffies_delta_to_clock_t(timer->expires - jiffies) : 0;
 161}
 162