kernel/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(unsigned long arg)
  35 {
  36         struct net_bridge *br = (struct net_bridge *)arg;
  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_USER_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(unsigned long arg)
  51 {
  52         struct net_bridge_port *p = (struct net_bridge_port *) arg;
  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(unsigned long arg)
  84 {
  85         struct net_bridge_port *p = (struct net_bridge_port *) arg;
  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         br_log_state(p);
 102         rcu_read_lock();
 103         br_ifinfo_notify(RTM_NEWLINK, p);
 104         rcu_read_unlock();
 105         spin_unlock(&br->lock);
 106 }
 107
 108 static void br_tcn_timer_expired(unsigned long arg)
 109 {
 110         struct net_bridge *br = (struct net_bridge *) arg;
 111
 112         br_debug(br, "tcn timer expired\n");
 113         spin_lock(&br->lock);
 114         if (!br_is_root_bridge(br) && (br->dev->flags & IFF_UP)) {
 115                 br_transmit_tcn(br);
 116
 117                 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
 118         }
 119         spin_unlock(&br->lock);
 120 }
 121
 122 static void br_topology_change_timer_expired(unsigned long arg)
 123 {
 124         struct net_bridge *br = (struct net_bridge *) arg;
 125
 126         br_debug(br, "topo change timer expired\n");
 127         spin_lock(&br->lock);
 128         br->topology_change_detected = 0;
 129         br->topology_change = 0;
 130         spin_unlock(&br->lock);
 131 }
 132
 133 static void br_hold_timer_expired(unsigned long arg)
 134 {
 135         struct net_bridge_port *p = (struct net_bridge_port *) arg;
 136
 137         br_debug(p->br, "port %u(%s) hold timer expired\n",
 138                  (unsigned int) p->port_no, p->dev->name);
 139
 140         spin_lock(&p->br->lock);
 141         if (p->config_pending)
 142                 br_transmit_config(p);
 143         spin_unlock(&p->br->lock);
 144 }
 145
 146 void br_stp_timer_init(struct net_bridge *br)
 147 {
 148         setup_timer(&br->hello_timer, br_hello_timer_expired,
 149                       (unsigned long) br);
 150
 151         setup_timer(&br->tcn_timer, br_tcn_timer_expired,
 152                       (unsigned long) br);
 153
 154         setup_timer(&br->topology_change_timer,
 155                       br_topology_change_timer_expired,
 156                       (unsigned long) br);
 157
 158         setup_timer(&br->gc_timer, br_fdb_cleanup, (unsigned long) br);
 159 }
 160
 161 void br_stp_port_timer_init(struct net_bridge_port *p)
 162 {
 163         setup_timer(&p->message_age_timer, br_message_age_timer_expired,
 164                       (unsigned long) p);
 165
 166         setup_timer(&p->forward_delay_timer, br_forward_delay_timer_expired,
 167                       (unsigned long) p);
 168
 169         setup_timer(&p->hold_timer, br_hold_timer_expired,
 170                       (unsigned long) p);
 171 }
 172
 173 /* Report ticks left (in USER_HZ) used for API */
 174 unsigned long br_timer_value(const struct timer_list *timer)
 175 {
 176         return timer_pending(timer)
 177                 ? jiffies_delta_to_clock_t(timer->expires - jiffies) : 0;
 178 }