release/src-rt-6.x.4708/linux/linux-2.6.36/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                 mod_timer(&br->hello_timer, round_jiffies(jiffies + br->hello_time));
  44         }
  45         spin_unlock(&br->lock);
  46 }
  47
  48 static void br_message_age_timer_expired(unsigned long arg)
  49 {
  50         struct net_bridge_port *p = (struct net_bridge_port *) arg;
  51         struct net_bridge *br = p->br;
  52         const bridge_id *id = &p->designated_bridge;
  53         int was_root;
  54
  55         if (p->state == BR_STATE_DISABLED)
  56                 return;
  57
  58         br_info(br, "port %u(%s) neighbor %.2x%.2x.%pM lost\n",
  59                 (unsigned) p->port_no, p->dev->name,
  60                 id->prio[0], id->prio[1], &id->addr);
  61
  62         /*
  63          * According to the spec, the message age timer cannot be
  64          * running when we are the root bridge. So..  this was_root
  65          * check is redundant. I'm leaving it in for now, though.
  66          */
  67         spin_lock(&br->lock);
  68         if (p->state == BR_STATE_DISABLED)
  69                 goto unlock;
  70         was_root = br_is_root_bridge(br);
  71
  72         br_become_designated_port(p);
  73         br_configuration_update(br);
  74         br_port_state_selection(br);
  75         if (br_is_root_bridge(br) && !was_root)
  76                 br_become_root_bridge(br);
  77  unlock:
  78         spin_unlock(&br->lock);
  79 }
  80
  81 static void br_forward_delay_timer_expired(unsigned long arg)
  82 {
  83         struct net_bridge_port *p = (struct net_bridge_port *) arg;
  84         struct net_bridge *br = p->br;
  85
  86         br_debug(br, "port %u(%s) forward delay timer\n",
  87                  (unsigned) p->port_no, p->dev->name);
  88         spin_lock(&br->lock);
  89         if (p->state == BR_STATE_LISTENING) {
  90                 p->state = BR_STATE_LEARNING;
  91                 mod_timer(&p->forward_delay_timer,
  92                           jiffies + br->forward_delay);
  93         } else if (p->state == BR_STATE_LEARNING) {
  94                 p->state = BR_STATE_FORWARDING;
  95                 if (br_is_designated_for_some_port(br))
  96                         br_topology_change_detection(br);
  97         }
  98         br_log_state(p);
  99         spin_unlock(&br->lock);
 100 }
 101
 102 static void br_tcn_timer_expired(unsigned long arg)
 103 {
 104         struct net_bridge *br = (struct net_bridge *) arg;
 105
 106         br_debug(br, "tcn timer expired\n");
 107         spin_lock(&br->lock);
 108         if (br->dev->flags & IFF_UP) {
 109                 br_transmit_tcn(br);
 110
 111                 mod_timer(&br->tcn_timer,jiffies + br->bridge_hello_time);
 112         }
 113         spin_unlock(&br->lock);
 114 }
 115
 116 static void br_topology_change_timer_expired(unsigned long arg)
 117 {
 118         struct net_bridge *br = (struct net_bridge *) arg;
 119
 120         br_debug(br, "topo change timer expired\n");
 121         spin_lock(&br->lock);
 122         br->topology_change_detected = 0;
 123         br->topology_change = 0;
 124         spin_unlock(&br->lock);
 125 }
 126
 127 static void br_hold_timer_expired(unsigned long arg)
 128 {
 129         struct net_bridge_port *p = (struct net_bridge_port *) arg;
 130
 131         br_debug(p->br, "port %u(%s) hold timer expired\n",
 132                  (unsigned) p->port_no, p->dev->name);
 133
 134         spin_lock(&p->br->lock);
 135         if (p->config_pending)
 136                 br_transmit_config(p);
 137         spin_unlock(&p->br->lock);
 138 }
 139
 140 void br_stp_timer_init(struct net_bridge *br)
 141 {
 142         setup_timer(&br->hello_timer, br_hello_timer_expired,
 143                       (unsigned long) br);
 144
 145         setup_timer(&br->tcn_timer, br_tcn_timer_expired,
 146                       (unsigned long) br);
 147
 148         setup_timer(&br->topology_change_timer,
 149                       br_topology_change_timer_expired,
 150                       (unsigned long) br);
 151
 152         setup_timer(&br->gc_timer, br_fdb_cleanup, (unsigned long) br);
 153 }
 154
 155 void br_stp_port_timer_init(struct net_bridge_port *p)
 156 {
 157         setup_timer(&p->message_age_timer, br_message_age_timer_expired,
 158                       (unsigned long) p);
 159
 160         setup_timer(&p->forward_delay_timer, br_forward_delay_timer_expired,
 161                       (unsigned long) p);
 162
 163         setup_timer(&p->hold_timer, br_hold_timer_expired,
 164                       (unsigned long) p);
 165 }
 166
 167 /* Report ticks left (in USER_HZ) used for API */
 168 unsigned long br_timer_value(const struct timer_list *timer)
 169 {
 170         return timer_pending(timer)
 171                 ? jiffies_to_clock_t(timer->expires - jiffies) : 0;
 172 }