1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Spanning tree protocol; timer-related code 4 * Linux ethernet bridge 5 * 6 * Authors: 7 * Lennert Buytenhek <buytenh@gnu.org> 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/times.h> 12 13 #include "br_private.h" 14 #include "br_private_stp.h" 15 16 /* called under bridge lock */ 17 static int br_is_designated_for_some_port(const struct net_bridge *br) 18 { 19 struct net_bridge_port *p; 20 21 list_for_each_entry(p, &br->port_list, list) { 22 if (p->state != BR_STATE_DISABLED && 23 !memcmp(&p->designated_bridge, &br->bridge_id, 8)) 24 return 1; 25 } 26 27 return 0; 28 } 29 30 static void br_hello_timer_expired(struct timer_list *t) 31 { 32 struct net_bridge *br = from_timer(br, t, hello_timer); 33 34 br_debug(br, "hello timer expired\n"); 35 spin_lock(&br->lock); 36 if (br->dev->flags & IFF_UP) { 37 br_config_bpdu_generation(br); 38 39 if (br->stp_enabled == BR_KERNEL_STP) 40 mod_timer(&br->hello_timer, 41 round_jiffies(jiffies + br->hello_time)); 42 } 43 spin_unlock(&br->lock); 44 } 45 46 static void br_message_age_timer_expired(struct timer_list *t) 47 { 48 struct net_bridge_port *p = from_timer(p, t, message_age_timer); 49 struct net_bridge *br = p->br; 50 const bridge_id *id = &p->designated_bridge; 51 int was_root; 52 53 if (p->state == BR_STATE_DISABLED) 54 return; 55 56 br_info(br, "port %u(%s) neighbor %.2x%.2x.%pM lost\n", 57 (unsigned int) p->port_no, p->dev->name, 58 id->prio[0], id->prio[1], &id->addr); 59 60 /* 61 * According to the spec, the message age timer cannot be 62 * running when we are the root bridge. So.. this was_root 63 * check is redundant. I'm leaving it in for now, though. 64 */ 65 spin_lock(&br->lock); 66 if (p->state == BR_STATE_DISABLED) 67 goto unlock; 68 was_root = br_is_root_bridge(br); 69 70 br_become_designated_port(p); 71 br_configuration_update(br); 72 br_port_state_selection(br); 73 if (br_is_root_bridge(br) && !was_root) 74 br_become_root_bridge(br); 75 unlock: 76 spin_unlock(&br->lock); 77 } 78 79 static void br_forward_delay_timer_expired(struct timer_list *t) 80 { 81 struct net_bridge_port *p = from_timer(p, t, forward_delay_timer); 82 struct net_bridge *br = p->br; 83 84 br_debug(br, "port %u(%s) forward delay timer\n", 85 (unsigned int) p->port_no, p->dev->name); 86 spin_lock(&br->lock); 87 if (p->state == BR_STATE_LISTENING) { 88 br_set_state(p, BR_STATE_LEARNING); 89 mod_timer(&p->forward_delay_timer, 90 jiffies + br->forward_delay); 91 } else if (p->state == BR_STATE_LEARNING) { 92 br_set_state(p, BR_STATE_FORWARDING); 93 if (br_is_designated_for_some_port(br)) 94 br_topology_change_detection(br); 95 netif_carrier_on(br->dev); 96 } 97 rcu_read_lock(); 98 br_ifinfo_notify(RTM_NEWLINK, NULL, p); 99 rcu_read_unlock(); 100 spin_unlock(&br->lock); 101 } 102 103 static void br_tcn_timer_expired(struct timer_list *t) 104 { 105 struct net_bridge *br = from_timer(br, t, tcn_timer); 106 107 br_debug(br, "tcn timer expired\n"); 108 spin_lock(&br->lock); 109 if (!br_is_root_bridge(br) && (br->dev->flags & IFF_UP)) { 110 br_transmit_tcn(br); 111 112 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time); 113 } 114 spin_unlock(&br->lock); 115 } 116 117 static void br_topology_change_timer_expired(struct timer_list *t) 118 { 119 struct net_bridge *br = from_timer(br, t, topology_change_timer); 120 121 br_debug(br, "topo change timer expired\n"); 122 spin_lock(&br->lock); 123 br->topology_change_detected = 0; 124 __br_set_topology_change(br, 0); 125 spin_unlock(&br->lock); 126 } 127 128 static void br_hold_timer_expired(struct timer_list *t) 129 { 130 struct net_bridge_port *p = from_timer(p, t, hold_timer); 131 132 br_debug(p->br, "port %u(%s) hold timer expired\n", 133 (unsigned int) p->port_no, p->dev->name); 134 135 spin_lock(&p->br->lock); 136 if (p->config_pending) 137 br_transmit_config(p); 138 spin_unlock(&p->br->lock); 139 } 140 141 void br_stp_timer_init(struct net_bridge *br) 142 { 143 timer_setup(&br->hello_timer, br_hello_timer_expired, 0); 144 timer_setup(&br->tcn_timer, br_tcn_timer_expired, 0); 145 timer_setup(&br->topology_change_timer, 146 br_topology_change_timer_expired, 0); 147 } 148 149 void br_stp_port_timer_init(struct net_bridge_port *p) 150 { 151 timer_setup(&p->message_age_timer, br_message_age_timer_expired, 0); 152 timer_setup(&p->forward_delay_timer, br_forward_delay_timer_expired, 0); 153 timer_setup(&p->hold_timer, br_hold_timer_expired, 0); 154 } 155 156 /* Report ticks left (in USER_HZ) used for API */ 157 unsigned long br_timer_value(const struct timer_list *timer) 158 { 159 return timer_pending(timer) 160 ? jiffies_delta_to_clock_t(timer->expires - jiffies) : 0; 161 } 162