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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 <[email protected]>
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->designated_bridge, &br->bridge_id, 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 = timer_container_of(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
46static void br_message_age_timer_expired(struct timer_list *t)
47{
48 struct net_bridge_port *p = timer_container_of(p, t,
49 message_age_timer);
50 struct net_bridge *br = p->br;
51 const bridge_id *id = &p->designated_bridge;
52 int was_root;
53
54 if (p->state == BR_STATE_DISABLED)
55 return;
56
57 br_info(br, "port %u(%s) neighbor %.2x%.2x.%pM lost\n",
58 (unsigned int) p->port_no, p->dev->name,
59 id->prio[0], id->prio[1], &id->addr);
60
61 /*
62 * According to the spec, the message age timer cannot be
63 * running when we are the root bridge. So.. this was_root
64 * check is redundant. I'm leaving it in for now, though.
65 */
66 spin_lock(&br->lock);
67 if (p->state == BR_STATE_DISABLED)
68 goto unlock;
69 was_root = br_is_root_bridge(br);
70
71 br_become_designated_port(p);
72 br_configuration_update(br);
73 br_port_state_selection(br);
74 if (br_is_root_bridge(br) && !was_root)
75 br_become_root_bridge(br);
76 unlock:
77 spin_unlock(&br->lock);
78}
79
80static void br_forward_delay_timer_expired(struct timer_list *t)
81{
82 struct net_bridge_port *p = timer_container_of(p, t,
83 forward_delay_timer);
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 rcu_read_lock();
100 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
101 rcu_read_unlock();
102 spin_unlock(&br->lock);
103}
104
105static void br_tcn_timer_expired(struct timer_list *t)
106{
107 struct net_bridge *br = timer_container_of(br, t, tcn_timer);
108
109 br_debug(br, "tcn timer expired\n");
110 spin_lock(&br->lock);
111 if (!br_is_root_bridge(br) && (br->dev->flags & IFF_UP)) {
112 br_transmit_tcn(br);
113
114 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
115 }
116 spin_unlock(&br->lock);
117}
118
119static void br_topology_change_timer_expired(struct timer_list *t)
120{
121 struct net_bridge *br = timer_container_of(br, t,
122 topology_change_timer);
123
124 br_debug(br, "topo change timer expired\n");
125 spin_lock(&br->lock);
126 br->topology_change_detected = 0;
127 __br_set_topology_change(br, 0);
128 spin_unlock(&br->lock);
129}
130
131static void br_hold_timer_expired(struct timer_list *t)
132{
133 struct net_bridge_port *p = timer_container_of(p, t, hold_timer);
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
144void br_stp_timer_init(struct net_bridge *br)
145{
146 timer_setup(&br->hello_timer, br_hello_timer_expired, 0);
147 timer_setup(&br->tcn_timer, br_tcn_timer_expired, 0);
148 timer_setup(&br->topology_change_timer,
149 br_topology_change_timer_expired, 0);
150}
151
152void br_stp_port_timer_init(struct net_bridge_port *p)
153{
154 timer_setup(&p->message_age_timer, br_message_age_timer_expired, 0);
155 timer_setup(&p->forward_delay_timer, br_forward_delay_timer_expired, 0);
156 timer_setup(&p->hold_timer, br_hold_timer_expired, 0);
157}
158
159/* Report ticks left (in USER_HZ) used for API */
160unsigned long br_timer_value(const struct timer_list *timer)
161{
162 return timer_pending(timer)
163 ? jiffies_delta_to_clock_t(READ_ONCE(timer->expires) - jiffies) : 0;
164}