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	br_ifinfo_notify(RTM_NEWLINK, p);
101	spin_unlock(&br->lock);
102}
103
104static void br_tcn_timer_expired(unsigned long arg)
105{
106	struct net_bridge *br = (struct net_bridge *) arg;
107
108	br_debug(br, "tcn timer expired\n");
109	spin_lock(&br->lock);
110	if (!br_is_root_bridge(br) && (br->dev->flags & IFF_UP)) {
111		br_transmit_tcn(br);
112
113		mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
114	}
115	spin_unlock(&br->lock);
116}
117
118static void br_topology_change_timer_expired(unsigned long arg)
119{
120	struct net_bridge *br = (struct net_bridge *) arg;
121
122	br_debug(br, "topo change timer expired\n");
123	spin_lock(&br->lock);
124	br->topology_change_detected = 0;
125	br->topology_change = 0;
126	spin_unlock(&br->lock);
127}
128
129static void br_hold_timer_expired(unsigned long arg)
130{
131	struct net_bridge_port *p = (struct net_bridge_port *) arg;
132
133	br_debug(p->br, "port %u(%s) hold timer expired\n",
134		 (unsigned int) p->port_no, p->dev->name);
135
136	spin_lock(&p->br->lock);
137	if (p->config_pending)
138		br_transmit_config(p);
139	spin_unlock(&p->br->lock);
140}
141
142void br_stp_timer_init(struct net_bridge *br)
143{
144	setup_timer(&br->hello_timer, br_hello_timer_expired,
145		      (unsigned long) br);
146
147	setup_timer(&br->tcn_timer, br_tcn_timer_expired,
148		      (unsigned long) br);
149
150	setup_timer(&br->topology_change_timer,
151		      br_topology_change_timer_expired,
152		      (unsigned long) br);
153
154	setup_timer(&br->gc_timer, br_fdb_cleanup, (unsigned long) br);
155}
156
157void br_stp_port_timer_init(struct net_bridge_port *p)
158{
159	setup_timer(&p->message_age_timer, br_message_age_timer_expired,
160		      (unsigned long) p);
161
162	setup_timer(&p->forward_delay_timer, br_forward_delay_timer_expired,
163		      (unsigned long) p);
164
165	setup_timer(&p->hold_timer, br_hold_timer_expired,
166		      (unsigned long) p);
167}
168
169/* Report ticks left (in USER_HZ) used for API */
170unsigned long br_timer_value(const struct timer_list *timer)
171{
172	return timer_pending(timer)
173		? jiffies_delta_to_clock_t(timer->expires - jiffies) : 0;
174}
175