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: &p->designated_bridge, q: &br->bridge_id, size: 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(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 | |
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(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 | |
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(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 | |
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(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 | |
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(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 | |
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(lock: &p->br->lock); |
136 | if (p->config_pending) |
137 | br_transmit_config(p); |
138 | spin_unlock(lock: &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(delta: timer->expires - jiffies) : 0; |
161 | } |
162 | |