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 */
br_is_designated_for_some_port(const struct net_bridge * br)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 
br_hello_timer_expired(struct timer_list * t)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 
br_message_age_timer_expired(struct timer_list * t)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 
br_forward_delay_timer_expired(struct timer_list * t)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 
br_tcn_timer_expired(struct timer_list * t)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 
br_topology_change_timer_expired(struct timer_list * t)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 
br_hold_timer_expired(struct timer_list * t)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 
br_stp_timer_init(struct net_bridge * br)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 
br_stp_port_timer_init(struct net_bridge_port * p)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 */
br_timer_value(const struct timer_list * timer)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