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 */
17static 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: &p->designated_bridge, q: &br->bridge_id, size: 8))
24 return 1;
25 }
26
27 return 0;
28}
29
30static 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(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(timer: &br->hello_timer,
41 expires: round_jiffies(j: jiffies + br->hello_time));
42 }
43 spin_unlock(lock: &br->lock);
44}
45
46static 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(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(lock: &br->lock);
77}
78
79static 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(lock: &br->lock);
87 if (p->state == BR_STATE_LISTENING) {
88 br_set_state(p, BR_STATE_LEARNING);
89 mod_timer(timer: &p->forward_delay_timer,
90 expires: 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(dev: br->dev);
96 }
97 rcu_read_lock();
98 br_ifinfo_notify(RTM_NEWLINK, NULL, port: p);
99 rcu_read_unlock();
100 spin_unlock(lock: &br->lock);
101}
102
103static 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(lock: &br->lock);
109 if (!br_is_root_bridge(br) && (br->dev->flags & IFF_UP)) {
110 br_transmit_tcn(br);
111
112 mod_timer(timer: &br->tcn_timer, expires: jiffies + br->bridge_hello_time);
113 }
114 spin_unlock(lock: &br->lock);
115}
116
117static 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(lock: &br->lock);
123 br->topology_change_detected = 0;
124 __br_set_topology_change(br, val: 0);
125 spin_unlock(lock: &br->lock);
126}
127
128static 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(lock: &p->br->lock);
136 if (p->config_pending)
137 br_transmit_config(p);
138 spin_unlock(lock: &p->br->lock);
139}
140
141void 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
149void 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 */
157unsigned long br_timer_value(const struct timer_list *timer)
158{
159 return timer_pending(timer)
160 ? jiffies_delta_to_clock_t(delta: timer->expires - jiffies) : 0;
161}
162

source code of linux/net/bridge/br_stp_timer.c