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  *      $Id: br_stp_timer.c,v 1.3 2000/05/05 02:17:17 davem Exp $
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/if_bridge.h>
  18 #include <linux/smp_lock.h>
  19 #include <asm/uaccess.h>
  20 #include "br_private.h"
  21 #include "br_private_stp.h"
  22
  23 static void dump_bridge_id(bridge_id *id)
  24 {
  25         printk("%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x", id->prio[0],
  26                id->prio[1], id->addr[0], id->addr[1], id->addr[2], id->addr[3],
  27                id->addr[4], id->addr[5]);
  28 }
  29
  30 /* called under bridge lock */
  31 static int br_is_designated_for_some_port(struct net_bridge *br)
  32 {
  33         struct net_bridge_port *p;
  34
  35         p = br->port_list;
  36         while (p != NULL) {
  37                 if (p->state != BR_STATE_DISABLED &&
  38                     !memcmp(&p->designated_bridge, &br->bridge_id, 8))
  39                         return 1;
  40
  41                 p = p->next;
  42         }
  43
  44         return 0;
  45 }
  46
  47 /* called under bridge lock */
  48 static void br_hello_timer_expired(struct net_bridge *br)
  49 {
  50         br_config_bpdu_generation(br);
  51         br_timer_set(&br->hello_timer, jiffies);
  52 }
  53
  54 /* called under bridge lock */
  55 static void br_message_age_timer_expired(struct net_bridge_port *p)
  56 {
  57         struct net_bridge *br;
  58         int was_root;
  59
  60         br = p->br;
  61         printk(KERN_INFO "%s: ", br->dev.name);
  62         printk("neighbour ");
  63         dump_bridge_id(&p->designated_bridge);
  64         printk(" lost on port %i(%s)\n", p->port_no, p->dev->name);
  65
  66         /*
  67          * According to the spec, the message age timer cannot be
  68          * running when we are the root bridge. So..  this was_root
  69          * check is redundant. I'm leaving it in for now, though.
  70          */
  71         was_root = br_is_root_bridge(br);
  72
  73         br_become_designated_port(p);
  74         br_configuration_update(br);
  75         br_port_state_selection(br);
  76         if (br_is_root_bridge(br) && !was_root)
  77                 br_become_root_bridge(br);
  78 }
  79
  80 /* called under bridge lock */
  81 static void br_forward_delay_timer_expired(struct net_bridge_port *p)
  82 {
  83         if (p->state == BR_STATE_LISTENING) {
  84                 printk(KERN_INFO "%s: port %i(%s) entering %s state\n",
  85                        p->br->dev.name, p->port_no, p->dev->name, "learning");
  86
  87                 p->state = BR_STATE_LEARNING;
  88                 br_timer_set(&p->forward_delay_timer, jiffies);
  89         } else if (p->state == BR_STATE_LEARNING) {
  90                 printk(KERN_INFO "%s: port %i(%s) entering %s state\n",
  91                        p->br->dev.name, p->port_no, p->dev->name, "forwarding");
  92
  93                 p->state = BR_STATE_FORWARDING;
  94                 if (br_is_designated_for_some_port(p->br))
  95                         br_topology_change_detection(p->br);
  96         }
  97 }
  98
  99 /* called under bridge lock */
 100 static void br_tcn_timer_expired(struct net_bridge *br)
 101 {
 102         printk(KERN_INFO "%s: retransmitting tcn bpdu\n", br->dev.name);
 103         br_transmit_tcn(br);
 104         br_timer_set(&br->tcn_timer, jiffies);
 105 }
 106
 107 /* called under bridge lock */
 108 static void br_topology_change_timer_expired(struct net_bridge *br)
 109 {
 110         br->topology_change_detected = 0;
 111         br->topology_change = 0;
 112 }
 113
 114 /* called under bridge lock */
 115 static void br_hold_timer_expired(struct net_bridge_port *p)
 116 {
 117         if (p->config_pending)
 118                 br_transmit_config(p);
 119 }
 120
 121 /* called under bridge lock */
 122 static void br_check_port_timers(struct net_bridge_port *p)
 123 {
 124         if (br_timer_has_expired(&p->message_age_timer, p->br->max_age)) {
 125                 br_timer_clear(&p->message_age_timer);
 126                 br_message_age_timer_expired(p);
 127         }
 128
 129         if (br_timer_has_expired(&p->forward_delay_timer, p->br->forward_delay)) {
 130                 br_timer_clear(&p->forward_delay_timer);
 131                 br_forward_delay_timer_expired(p);
 132         }
 133
 134         if (br_timer_has_expired(&p->hold_timer, BR_HOLD_TIME)) {
 135                 br_timer_clear(&p->hold_timer);
 136                 br_hold_timer_expired(p);
 137         }
 138 }
 139
 140 /* called under bridge lock */
 141 static void br_check_timers(struct net_bridge *br)
 142 {
 143         struct net_bridge_port *p;
 144
 145         if (br_timer_has_expired(&br->gc_timer, br->gc_interval)) {
 146                 br_timer_set(&br->gc_timer, jiffies);
 147                 br_fdb_cleanup(br);
 148         }
 149
 150         if (br_timer_has_expired(&br->hello_timer, br->hello_time)) {
 151                 br_timer_clear(&br->hello_timer);
 152                 br_hello_timer_expired(br);
 153         }
 154
 155         if (br_timer_has_expired(&br->tcn_timer, br->bridge_hello_time)) {
 156                 br_timer_clear(&br->tcn_timer);
 157                 br_tcn_timer_expired(br);
 158         }
 159
 160         if (br_timer_has_expired(&br->topology_change_timer, br->bridge_forward_delay + br->bridge_max_age)) {
 161                 br_timer_clear(&br->topology_change_timer);
 162                 br_topology_change_timer_expired(br);
 163         }
 164
 165         p = br->port_list;
 166         while (p != NULL) {
 167                 if (p->state != BR_STATE_DISABLED)
 168                         br_check_port_timers(p);
 169
 170                 p = p->next;
 171         }
 172 }
 173
 174 void br_tick(unsigned long __data)
 175 {
 176         struct net_bridge *br = (struct net_bridge *)__data;
 177
 178         read_lock(&br->lock);
 179         br_check_timers(br);
 180         read_unlock(&br->lock);
 181
 182         br->tick.expires = jiffies + 1;
 183         add_timer(&br->tick);
 184 }