Root/net/bridge/br_stp_timer.c

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) 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) p->port_no, p->dev->name);
88    spin_lock(&br->lock);
89    if (p->state == BR_STATE_LISTENING) {
90        p->state = BR_STATE_LEARNING;
91        mod_timer(&p->forward_delay_timer,
92              jiffies + br->forward_delay);
93    } else if (p->state == BR_STATE_LEARNING) {
94        p->state = 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    spin_unlock(&br->lock);
101}
102
103static void br_tcn_timer_expired(unsigned long arg)
104{
105    struct net_bridge *br = (struct net_bridge *) arg;
106
107    br_debug(br, "tcn timer expired\n");
108    spin_lock(&br->lock);
109    if (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
117static void br_topology_change_timer_expired(unsigned long arg)
118{
119    struct net_bridge *br = (struct net_bridge *) arg;
120
121    br_debug(br, "topo change timer expired\n");
122    spin_lock(&br->lock);
123    br->topology_change_detected = 0;
124    br->topology_change = 0;
125    spin_unlock(&br->lock);
126}
127
128static void br_hold_timer_expired(unsigned long arg)
129{
130    struct net_bridge_port *p = (struct net_bridge_port *) arg;
131
132    br_debug(p->br, "port %u(%s) hold timer expired\n",
133         (unsigned) 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
141void br_stp_timer_init(struct net_bridge *br)
142{
143    setup_timer(&br->hello_timer, br_hello_timer_expired,
144              (unsigned long) br);
145
146    setup_timer(&br->tcn_timer, br_tcn_timer_expired,
147              (unsigned long) br);
148
149    setup_timer(&br->topology_change_timer,
150              br_topology_change_timer_expired,
151              (unsigned long) br);
152
153    setup_timer(&br->gc_timer, br_fdb_cleanup, (unsigned long) br);
154}
155
156void br_stp_port_timer_init(struct net_bridge_port *p)
157{
158    setup_timer(&p->message_age_timer, br_message_age_timer_expired,
159              (unsigned long) p);
160
161    setup_timer(&p->forward_delay_timer, br_forward_delay_timer_expired,
162              (unsigned long) p);
163
164    setup_timer(&p->hold_timer, br_hold_timer_expired,
165              (unsigned long) p);
166}
167
168/* Report ticks left (in USER_HZ) used for API */
169unsigned long br_timer_value(const struct timer_list *timer)
170{
171    return timer_pending(timer)
172        ? jiffies_to_clock_t(timer->expires - jiffies) : 0;
173}
174

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