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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Linux network device link state notification
3 *
4 * Author:
5 * Stefan Rompf <sux@loplof.de>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 */
13
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/module.h>
15#include <linux/netdevice.h>
16#include <linux/if.h>
17#include <net/sock.h>
Tommy S. Christensencacaddf2005-05-03 16:18:52 -070018#include <net/pkt_sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/rtnetlink.h>
20#include <linux/jiffies.h>
21#include <linux/spinlock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/slab.h>
23#include <linux/workqueue.h>
24#include <linux/bitops.h>
25#include <asm/types.h>
26
27
28enum lw_bits {
Herbert Xud9568ba2007-05-09 00:17:30 -070029 LW_URGENT = 0,
Linus Torvalds1da177e2005-04-16 15:20:36 -070030};
31
32static unsigned long linkwatch_flags;
33static unsigned long linkwatch_nextevent;
34
David Howells65f27f32006-11-22 14:55:48 +000035static void linkwatch_event(struct work_struct *dummy);
36static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event);
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
Herbert Xu572a1032007-05-08 18:34:17 -070038static struct net_device *lweventlist;
Linus Torvalds1da177e2005-04-16 15:20:36 -070039static DEFINE_SPINLOCK(lweventlist_lock);
40
Stefan Rompfb00055a2006-03-20 17:09:11 -080041static unsigned char default_operstate(const struct net_device *dev)
42{
43 if (!netif_carrier_ok(dev))
44 return (dev->ifindex != dev->iflink ?
45 IF_OPER_LOWERLAYERDOWN : IF_OPER_DOWN);
46
47 if (netif_dormant(dev))
48 return IF_OPER_DORMANT;
49
50 return IF_OPER_UP;
51}
52
53
54static void rfc2863_policy(struct net_device *dev)
55{
56 unsigned char operstate = default_operstate(dev);
57
58 if (operstate == dev->operstate)
59 return;
60
61 write_lock_bh(&dev_base_lock);
62
63 switch(dev->link_mode) {
64 case IF_LINK_MODE_DORMANT:
65 if (operstate == IF_OPER_UP)
66 operstate = IF_OPER_DORMANT;
67 break;
68
69 case IF_LINK_MODE_DEFAULT:
70 default:
71 break;
Stephen Hemminger3ff50b72007-04-20 17:09:22 -070072 }
Stefan Rompfb00055a2006-03-20 17:09:11 -080073
74 dev->operstate = operstate;
75
76 write_unlock_bh(&dev_base_lock);
77}
78
79
David S. Miller6fa98642008-07-08 23:01:06 -070080static bool linkwatch_urgent_event(struct net_device *dev)
Herbert Xu294cc442007-05-08 18:36:28 -070081{
82 return netif_running(dev) && netif_carrier_ok(dev) &&
David S. Miller6fa98642008-07-08 23:01:06 -070083 qdisc_tx_changing(dev);
Herbert Xu294cc442007-05-08 18:36:28 -070084}
85
86
87static void linkwatch_add_event(struct net_device *dev)
88{
89 unsigned long flags;
90
91 spin_lock_irqsave(&lweventlist_lock, flags);
92 dev->link_watch_next = lweventlist;
93 lweventlist = dev;
94 spin_unlock_irqrestore(&lweventlist_lock, flags);
95}
96
97
Herbert Xud9568ba2007-05-09 00:17:30 -070098static void linkwatch_schedule_work(int urgent)
Herbert Xu294cc442007-05-08 18:36:28 -070099{
Herbert Xud9568ba2007-05-09 00:17:30 -0700100 unsigned long delay = linkwatch_nextevent - jiffies;
101
102 if (test_bit(LW_URGENT, &linkwatch_flags))
Herbert Xu294cc442007-05-08 18:36:28 -0700103 return;
104
Herbert Xud9568ba2007-05-09 00:17:30 -0700105 /* Minimise down-time: drop delay for up event. */
106 if (urgent) {
107 if (test_and_set_bit(LW_URGENT, &linkwatch_flags))
108 return;
Herbert Xu294cc442007-05-08 18:36:28 -0700109 delay = 0;
Herbert Xudb0ccff2007-05-08 23:22:43 -0700110 }
Herbert Xu294cc442007-05-08 18:36:28 -0700111
Herbert Xud9568ba2007-05-09 00:17:30 -0700112 /* If we wrap around we'll delay it by at most HZ. */
113 if (delay > HZ)
114 delay = 0;
115
116 /*
117 * This is true if we've scheduled it immeditately or if we don't
118 * need an immediate execution and it's already pending.
119 */
120 if (schedule_delayed_work(&linkwatch_work, delay) == !delay)
121 return;
122
123 /* Don't bother if there is nothing urgent. */
124 if (!test_bit(LW_URGENT, &linkwatch_flags))
125 return;
126
127 /* It's already running which is good enough. */
128 if (!cancel_delayed_work(&linkwatch_work))
129 return;
130
131 /* Otherwise we reschedule it again for immediate exection. */
132 schedule_delayed_work(&linkwatch_work, 0);
Herbert Xu294cc442007-05-08 18:36:28 -0700133}
134
135
136static void __linkwatch_run_queue(int urgent_only)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137{
Herbert Xu572a1032007-05-08 18:34:17 -0700138 struct net_device *next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139
Herbert Xu294cc442007-05-08 18:36:28 -0700140 /*
141 * Limit the number of linkwatch events to one
142 * per second so that a runaway driver does not
143 * cause a storm of messages on the netlink
144 * socket. This limit does not apply to up events
145 * while the device qdisc is down.
146 */
147 if (!urgent_only)
148 linkwatch_nextevent = jiffies + HZ;
Herbert Xud9568ba2007-05-09 00:17:30 -0700149 /* Limit wrap-around effect on delay. */
150 else if (time_after(linkwatch_nextevent, jiffies + HZ))
151 linkwatch_nextevent = jiffies;
152
153 clear_bit(LW_URGENT, &linkwatch_flags);
Herbert Xu294cc442007-05-08 18:36:28 -0700154
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 spin_lock_irq(&lweventlist_lock);
Herbert Xu572a1032007-05-08 18:34:17 -0700156 next = lweventlist;
157 lweventlist = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 spin_unlock_irq(&lweventlist_lock);
159
Herbert Xu572a1032007-05-08 18:34:17 -0700160 while (next) {
161 struct net_device *dev = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
Herbert Xu572a1032007-05-08 18:34:17 -0700163 next = dev->link_watch_next;
164
Herbert Xu294cc442007-05-08 18:36:28 -0700165 if (urgent_only && !linkwatch_urgent_event(dev)) {
166 linkwatch_add_event(dev);
167 continue;
168 }
169
Herbert Xu572a1032007-05-08 18:34:17 -0700170 /*
171 * Make sure the above read is complete since it can be
172 * rewritten as soon as we clear the bit below.
173 */
174 smp_mb__before_clear_bit();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
176 /* We are about to handle this device,
177 * so new events can be accepted
178 */
179 clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
180
Stefan Rompfb00055a2006-03-20 17:09:11 -0800181 rfc2863_policy(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 if (dev->flags & IFF_UP) {
David S. Miller6fa98642008-07-08 23:01:06 -0700183 if (netif_carrier_ok(dev))
Tommy S. Christensencacaddf2005-05-03 16:18:52 -0700184 dev_activate(dev);
David S. Miller6fa98642008-07-08 23:01:06 -0700185 else
Tommy S. Christensencacaddf2005-05-03 16:18:52 -0700186 dev_deactivate(dev);
187
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 netdev_state_change(dev);
189 }
190
191 dev_put(dev);
192 }
Herbert Xu294cc442007-05-08 18:36:28 -0700193
194 if (lweventlist)
Herbert Xud9568ba2007-05-09 00:17:30 -0700195 linkwatch_schedule_work(0);
Herbert Xu294cc442007-05-08 18:36:28 -0700196}
197
198
199/* Must be called with the rtnl semaphore held */
200void linkwatch_run_queue(void)
201{
202 __linkwatch_run_queue(0);
YOSHIFUJI Hideaki4ec93ed2007-02-09 23:24:36 +0900203}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
205
David Howells65f27f32006-11-22 14:55:48 +0000206static void linkwatch_event(struct work_struct *dummy)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207{
Stephen Hemminger6756ae42006-03-20 22:23:58 -0800208 rtnl_lock();
Herbert Xu294cc442007-05-08 18:36:28 -0700209 __linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies));
Stephen Hemminger6756ae42006-03-20 22:23:58 -0800210 rtnl_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211}
212
213
214void linkwatch_fire_event(struct net_device *dev)
215{
David S. Miller6fa98642008-07-08 23:01:06 -0700216 bool urgent = linkwatch_urgent_event(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217
Herbert Xud9568ba2007-05-09 00:17:30 -0700218 if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 dev_hold(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220
Herbert Xu294cc442007-05-08 18:36:28 -0700221 linkwatch_add_event(dev);
Herbert Xud9568ba2007-05-09 00:17:30 -0700222 } else if (!urgent)
223 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
Herbert Xud9568ba2007-05-09 00:17:30 -0700225 linkwatch_schedule_work(urgent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226}
227
228EXPORT_SYMBOL(linkwatch_fire_event);