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                 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 int) 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 int) p->port_no, p->dev->name);
  88         spin_lock(&br->lock);
  89         if (p->state == BR_STATE_LISTENING) {
  90                 br_set_state(p, BR_STATE_LEARNING);
  91                 mod_timer(&p->forward_delay_timer,
  92                           jiffies + br->forward_delay);
  93         } else if (p->state == BR_STATE_LEARNING) {
  94                 br_set_state(p, BR_STATE_FORWARDING);
  95                 if (br_is_designated_for_some_port(br))
  96                         br_topology_change_detection(br);
  97                 netif_carrier_on(br->dev);
  98         }
  99         br_log_state(p);
 100         rcu_read_lock();
 101         br_ifinfo_notify(RTM_NEWLINK, p);
 102         rcu_read_unlock();
 103         spin_unlock(&br->lock);
 104 }
 105
 106 static void br_tcn_timer_expired(unsigned long arg)
 107 {
 108         struct net_bridge *br = (struct net_bridge *) arg;
 109
 110         br_debug(br, "tcn timer expired\n");
 111         spin_lock(&br->lock);
 112         if (!br_is_root_bridge(br) && (br->dev->flags & IFF_UP)) {
 113                 br_transmit_tcn(br);
 114
 115                 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
 116         }
 117         spin_unlock(&br->lock);
 118 }
 119
 120 static void br_topology_change_timer_expired(unsigned long arg)
 121 {
 122         struct net_bridge *br = (struct net_bridge *) arg;
 123
 124         br_debug(br, "topo change timer expired\n");
 125         spin_lock(&br->lock);
 126         br->topology_change_detected = 0;
 127         br->topology_change = 0;
 128         spin_unlock(&br->lock);
 129 }
 130
 131 static void br_hold_timer_expired(unsigned long arg)
 132 {
 133         struct net_bridge_port *p = (struct net_bridge_port *) arg;
 134
 135         br_debug(p->br, "port %u(%s) hold timer expired\n",
 136                  (unsigned int) p->port_no, p->dev->name);
 137
 138         spin_lock(&p->br->lock);
 139         if (p->config_pending)
 140                 br_transmit_config(p);
 141         spin_unlock(&p->br->lock);
 142 }
 143
 144 void br_stp_timer_init(struct net_bridge *br)
 145 {
 146         setup_timer(&br->hello_timer, br_hello_timer_expired,
 147                       (unsigned long) br);
 148
 149         setup_timer(&br->tcn_timer, br_tcn_timer_expired,
 150                       (unsigned long) br);
 151
 152         setup_timer(&br->topology_change_timer,
 153                       br_topology_change_timer_expired,
 154                       (unsigned long) br);
 155
 156         setup_timer(&br->gc_timer, br_fdb_cleanup, (unsigned long) br);
 157 }
 158
 159 void br_stp_port_timer_init(struct net_bridge_port *p)
 160 {
 161         setup_timer(&p->message_age_timer, br_message_age_timer_expired,
 162                       (unsigned long) p);
 163
 164         setup_timer(&p->forward_delay_timer, br_forward_delay_timer_expired,
 165                       (unsigned long) p);
 166
 167         setup_timer(&p->hold_timer, br_hold_timer_expired,
 168                       (unsigned long) p);
 169 }
 170
 171 /* Report ticks left (in USER_HZ) used for API */
 172 unsigned long br_timer_value(const struct timer_list *timer)
 173 {
 174         return timer_pending(timer)
 175                 ? jiffies_delta_to_clock_t(timer->expires - jiffies) : 0;
 176 }