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 } 166