2 * Linux network device link state notification
5 * Stefan Rompf <sux@loplof.de>
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.
14 #include <linux/module.h>
15 #include <linux/netdevice.h>
18 #include <net/pkt_sched.h>
19 #include <linux/rtnetlink.h>
20 #include <linux/jiffies.h>
21 #include <linux/spinlock.h>
22 #include <linux/slab.h>
23 #include <linux/workqueue.h>
24 #include <linux/bitops.h>
25 #include <asm/types.h>
32 static unsigned long linkwatch_flags;
33 static unsigned long linkwatch_nextevent;
35 static void linkwatch_event(struct work_struct *dummy);
36 static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event);
38 static struct net_device *lweventlist;
39 static DEFINE_SPINLOCK(lweventlist_lock);
41 static unsigned char default_operstate(const struct net_device *dev)
43 if (!netif_carrier_ok(dev))
44 return (dev->ifindex != dev->iflink ?
45 IF_OPER_LOWERLAYERDOWN : IF_OPER_DOWN);
47 if (netif_dormant(dev))
48 return IF_OPER_DORMANT;
54 static void rfc2863_policy(struct net_device *dev)
56 unsigned char operstate = default_operstate(dev);
58 if (operstate == dev->operstate)
61 write_lock_bh(&dev_base_lock);
63 switch(dev->link_mode) {
64 case IF_LINK_MODE_DORMANT:
65 if (operstate == IF_OPER_UP)
66 operstate = IF_OPER_DORMANT;
69 case IF_LINK_MODE_DEFAULT:
74 dev->operstate = operstate;
76 write_unlock_bh(&dev_base_lock);
80 static int linkwatch_urgent_event(struct net_device *dev)
82 return netif_running(dev) && netif_carrier_ok(dev) &&
83 dev->qdisc != dev->qdisc_sleeping;
87 static void linkwatch_add_event(struct net_device *dev)
91 spin_lock_irqsave(&lweventlist_lock, flags);
92 dev->link_watch_next = lweventlist;
94 spin_unlock_irqrestore(&lweventlist_lock, flags);
98 static void linkwatch_schedule_work(unsigned long delay)
100 if (test_and_set_bit(LW_RUNNING, &linkwatch_flags))
103 /* If we wrap around we'll delay it by at most HZ. */
105 linkwatch_nextevent = jiffies;
109 schedule_delayed_work(&linkwatch_work, delay);
113 static void __linkwatch_run_queue(int urgent_only)
115 struct net_device *next;
118 * Limit the number of linkwatch events to one
119 * per second so that a runaway driver does not
120 * cause a storm of messages on the netlink
121 * socket. This limit does not apply to up events
122 * while the device qdisc is down.
125 linkwatch_nextevent = jiffies + HZ;
126 clear_bit(LW_RUNNING, &linkwatch_flags);
128 spin_lock_irq(&lweventlist_lock);
131 spin_unlock_irq(&lweventlist_lock);
134 struct net_device *dev = next;
136 next = dev->link_watch_next;
138 if (urgent_only && !linkwatch_urgent_event(dev)) {
139 linkwatch_add_event(dev);
144 * Make sure the above read is complete since it can be
145 * rewritten as soon as we clear the bit below.
147 smp_mb__before_clear_bit();
149 /* We are about to handle this device,
150 * so new events can be accepted
152 clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
155 if (dev->flags & IFF_UP) {
156 if (netif_carrier_ok(dev)) {
157 WARN_ON(dev->qdisc_sleeping == &noop_qdisc);
162 netdev_state_change(dev);
169 linkwatch_schedule_work(linkwatch_nextevent - jiffies);
173 /* Must be called with the rtnl semaphore held */
174 void linkwatch_run_queue(void)
176 __linkwatch_run_queue(0);
180 static void linkwatch_event(struct work_struct *dummy)
183 __linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies));
188 void linkwatch_fire_event(struct net_device *dev)
190 if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {
195 linkwatch_add_event(dev);
197 delay = linkwatch_nextevent - jiffies;
199 /* Minimise down-time: drop delay for up event. */
200 if (linkwatch_urgent_event(dev))
203 linkwatch_schedule_work(delay);
207 EXPORT_SYMBOL(linkwatch_fire_event);