net/bridge/br_stp_timer.c

   1 /*
   2  *      Spanning tree protocol; timer-related code
   3  *      Linux ethernet bridge
   4  *
   5  *      Authors:
   6  *      Lennert Buytenhek               <buytenh@gnu.org>
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/times.h>
  16
  17 #include "br_private.h"
  18 #include "br_private_stp.h"
  19
  20 /* called under bridge lock */
  21 static int br_is_designated_for_some_port(const struct net_bridge *br)
  22 {
  23         struct net_bridge_port *p;
  24
  25         list_for_each_entry(p, &br->port_list, list) {
  26                 if (p->state != BR_STATE_DISABLED &&
  27                     !memcmp(&p->designated_bridge, &br->bridge_id, 8))
  28                         return 1;
  29         }
  30
  31         return 0;
  32 }
  33
  34 static void br_hello_timer_expired(struct timer_list *t)
  35 {
  36         struct net_bridge *br = from_timer(br, t, hello_timer);
  37
  38         br_debug(br, "hello timer expired\n");
  39         spin_lock(&br->lock);
  40         if (br->dev->flags & IFF_UP) {
  41                 br_config_bpdu_generation(br);
  42
  43                 if (br->stp_enabled == BR_KERNEL_STP)
  44                         mod_timer(&br->hello_timer,
  45                                   round_jiffies(jiffies + br->hello_time));
  46         }
  47         spin_unlock(&br->lock);
  48 }
  49
  50 static void br_message_age_timer_expired(struct timer_list *t)
  51 {
  52         struct net_bridge_port *p = from_timer(p, t, message_age_timer);
  53         struct net_bridge *br = p->br;
  54         const bridge_id *id = &p->designated_bridge;
  55         int was_root;
  56
  57         if (p->state == BR_STATE_DISABLED)
  58                 return;
  59
  60         br_info(br, "port %u(%s) neighbor %.2x%.2x.%pM lost\n",
  61                 (unsigned int) p->port_no, p->dev->name,
  62                 id->prio[0], id->prio[1], &id->addr);
  63
  64         /*
  65          * According to the spec, the message age timer cannot be
  66          * running when we are the root bridge. So..  this was_root
  67          * check is redundant. I'm leaving it in for now, though.
  68          */
  69         spin_lock(&br->lock);
  70         if (p->state == BR_STATE_DISABLED)
  71                 goto unlock;
  72         was_root = br_is_root_bridge(br);
  73
  74         br_become_designated_port(p);
  75         br_configuration_update(br);
  76         br_port_state_selection(br);
  77         if (br_is_root_bridge(br) && !was_root)
  78                 br_become_root_bridge(br);
  79  unlock:
  80         spin_unlock(&br->lock);
  81 }
  82
  83 static void br_forward_delay_timer_expired(struct timer_list *t)
  84 {
  85         struct net_bridge_port *p = from_timer(p, t, forward_delay_timer);
  86         struct net_bridge *br = p->br;
  87
  88         br_debug(br, "port %u(%s) forward delay timer\n",
  89                  (unsigned int) p->port_no, p->dev->name);
  90         spin_lock(&br->lock);
  91         if (p->state == BR_STATE_LISTENING) {
  92                 br_set_state(p, BR_STATE_LEARNING);
  93                 mod_timer(&p->forward_delay_timer,
  94                           jiffies + br->forward_delay);
  95         } else if (p->state == BR_STATE_LEARNING) {
  96                 br_set_state(p, BR_STATE_FORWARDING);
  97                 if (br_is_designated_for_some_port(br))
  98                         br_topology_change_detection(br);
  99                 netif_carrier_on(br->dev);
 100         }
 101         rcu_read_lock();
 102         br_ifinfo_notify(RTM_NEWLINK, NULL, p);
 103         rcu_read_unlock();
 104         spin_unlock(&br->lock);
 105 }
 106
 107 static void br_tcn_timer_expired(struct timer_list *t)
 108 {
 109         struct net_bridge *br = from_timer(br, t, tcn_timer);
 110
 111         br_debug(br, "tcn timer expired\n");
 112         spin_lock(&br->lock);
 113         if (!br_is_root_bridge(br) && (br->dev->flags & IFF_UP)) {
 114                 br_transmit_tcn(br);
 115
 116                 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
 117         }
 118         spin_unlock(&br->lock);
 119 }
 120
 121 static void br_topology_change_timer_expired(struct timer_list *t)
 122 {
 123         struct net_bridge *br = from_timer(br, t, topology_change_timer);
 124
 125         br_debug(br, "topo change timer expired\n");
 126         spin_lock(&br->lock);
 127         br->topology_change_detected = 0;
 128         __br_set_topology_change(br, 0);
 129         spin_unlock(&br->lock);
 130 }
 131
 132 static void br_hold_timer_expired(struct timer_list *t)
 133 {
 134         struct net_bridge_port *p = from_timer(p, t, hold_timer);
 135
 136         br_debug(p->br, "port %u(%s) hold timer expired\n",
 137                  (unsigned int) p->port_no, p->dev->name);
 138
 139         spin_lock(&p->br->lock);
 140         if (p->config_pending)
 141                 br_transmit_config(p);
 142         spin_unlock(&p->br->lock);
 143 }
 144
 145 void br_stp_timer_init(struct net_bridge *br)
 146 {
 147         timer_setup(&br->hello_timer, br_hello_timer_expired, 0);
 148         timer_setup(&br->tcn_timer, br_tcn_timer_expired, 0);
 149         timer_setup(&br->topology_change_timer,
 150                     br_topology_change_timer_expired, 0);
 151 }
 152
 153 void br_stp_port_timer_init(struct net_bridge_port *p)
 154 {
 155         timer_setup(&p->message_age_timer, br_message_age_timer_expired, 0);
 156         timer_setup(&p->forward_delay_timer, br_forward_delay_timer_expired, 0);
 157         timer_setup(&p->hold_timer, br_hold_timer_expired, 0);
 158 }
 159
 160 /* Report ticks left (in USER_HZ) used for API */
 161 unsigned long br_timer_value(const struct timer_list *timer)
 162 {
 163         return timer_pending(timer)
 164                 ? jiffies_delta_to_clock_t(timer->expires - jiffies) : 0;
 165 }