1/*
2 *	Spanning tree protocol; timer-related code
3 *	Linux ethernet bridge
4 *
5 *	Authors:
6 *	Lennert Buytenhek		<buytenh@gnu.org>
7 *
8 *	This program is free software; you can redistribute it and/or
9 *	modify it under the terms of the GNU General Public License
10 *	as published by the Free Software Foundation; either version
11 *	2 of the License, or (at your option) any later version.
12 */
13
14#include <linux/kernel.h>
15#include <linux/times.h>
16
17#include "br_private.h"
18#include "br_private_stp.h"
19
20/* called under bridge lock */
21static int br_is_designated_for_some_port(const struct net_bridge *br)
22{
23	struct net_bridge_port *p;
24
25	list_for_each_entry(p, &br->port_list, list) {
26		if (p->state != BR_STATE_DISABLED &&
27		    !memcmp(&p->designated_bridge, &br->bridge_id, 8))
28			return 1;
29	}
30
31	return 0;
32}
33
34static void br_hello_timer_expired(unsigned long arg)
35{
36	struct net_bridge *br = (struct net_bridge *)arg;
37
38	br_debug(br, "hello timer expired\n");
39	spin_lock(&br->lock);
40	if (br->dev->flags & IFF_UP) {
41		br_config_bpdu_generation(br);
42
43		mod_timer(&br->hello_timer, round_jiffies(jiffies + br->hello_time));
44	}
45	spin_unlock(&br->lock);
46}
47
48static void br_message_age_timer_expired(unsigned long arg)
49{
50	struct net_bridge_port *p = (struct net_bridge_port *) arg;
51	struct net_bridge *br = p->br;
52	const bridge_id *id = &p->designated_bridge;
53	int was_root;
54
55	if (p->state == BR_STATE_DISABLED)
56		return;
57
58	br_info(br, "port %u(%s) neighbor %.2x%.2x.%pM lost\n",
59		(unsigned int) p->port_no, p->dev->name,
60		id->prio[0], id->prio[1], &id->addr);
61
62	/*
63	 * According to the spec, the message age timer cannot be
64	 * running when we are the root bridge. So..  this was_root
65	 * check is redundant. I'm leaving it in for now, though.
66	 */
67	spin_lock(&br->lock);
68	if (p->state == BR_STATE_DISABLED)
69		goto unlock;
70	was_root = br_is_root_bridge(br);
71
72	br_become_designated_port(p);
73	br_configuration_update(br);
74	br_port_state_selection(br);
75	if (br_is_root_bridge(br) && !was_root)
76		br_become_root_bridge(br);
77 unlock:
78	spin_unlock(&br->lock);
79}
80
81static void br_forward_delay_timer_expired(unsigned long arg)
82{
83	struct net_bridge_port *p = (struct net_bridge_port *) arg;
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	br_log_state(p);
100	rcu_read_lock();
101	br_ifinfo_notify(RTM_NEWLINK, p);
102	rcu_read_unlock();
103	spin_unlock(&br->lock);
104}
105
106static void br_tcn_timer_expired(unsigned long arg)
107{
108	struct net_bridge *br = (struct net_bridge *) arg;
109
110	br_debug(br, "tcn timer expired\n");
111	spin_lock(&br->lock);
112	if (!br_is_root_bridge(br) && (br->dev->flags & IFF_UP)) {
113		br_transmit_tcn(br);
114
115		mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
116	}
117	spin_unlock(&br->lock);
118}
119
120static void br_topology_change_timer_expired(unsigned long arg)
121{
122	struct net_bridge *br = (struct net_bridge *) arg;
123
124	br_debug(br, "topo change timer expired\n");
125	spin_lock(&br->lock);
126	br->topology_change_detected = 0;
127	br->topology_change = 0;
128	spin_unlock(&br->lock);
129}
130
131static void br_hold_timer_expired(unsigned long arg)
132{
133	struct net_bridge_port *p = (struct net_bridge_port *) arg;
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	setup_timer(&br->hello_timer, br_hello_timer_expired,
147		      (unsigned long) br);
148
149	setup_timer(&br->tcn_timer, br_tcn_timer_expired,
150		      (unsigned long) br);
151
152	setup_timer(&br->topology_change_timer,
153		      br_topology_change_timer_expired,
154		      (unsigned long) br);
155
156	setup_timer(&br->gc_timer, br_fdb_cleanup, (unsigned long) br);
157}
158
159void br_stp_port_timer_init(struct net_bridge_port *p)
160{
161	setup_timer(&p->message_age_timer, br_message_age_timer_expired,
162		      (unsigned long) p);
163
164	setup_timer(&p->forward_delay_timer, br_forward_delay_timer_expired,
165		      (unsigned long) p);
166
167	setup_timer(&p->hold_timer, br_hold_timer_expired,
168		      (unsigned long) p);
169}
170
171/* Report ticks left (in USER_HZ) used for API */
172unsigned long br_timer_value(const struct timer_list *timer)
173{
174	return timer_pending(timer)
175		? jiffies_delta_to_clock_t(timer->expires - jiffies) : 0;
176}
177