2005-04-16 22:20:36 +00:00
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/*
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* Linux network device link state notification
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*
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* Author:
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* Stefan Rompf <sux@loplof.de>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <linux/if.h>
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#include <net/sock.h>
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2005-05-03 23:18:52 +00:00
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#include <net/pkt_sched.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/rtnetlink.h>
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#include <linux/jiffies.h>
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#include <linux/spinlock.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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#include <linux/bitops.h>
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#include <asm/types.h>
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enum lw_bits {
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2007-05-09 07:17:30 +00:00
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LW_URGENT = 0,
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2005-04-16 22:20:36 +00:00
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};
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static unsigned long linkwatch_flags;
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static unsigned long linkwatch_nextevent;
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2006-11-22 14:55:48 +00:00
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static void linkwatch_event(struct work_struct *dummy);
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static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event);
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2005-04-16 22:20:36 +00:00
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2007-05-09 01:34:17 +00:00
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static struct net_device *lweventlist;
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2005-04-16 22:20:36 +00:00
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static DEFINE_SPINLOCK(lweventlist_lock);
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2006-03-21 01:09:11 +00:00
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static unsigned char default_operstate(const struct net_device *dev)
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{
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if (!netif_carrier_ok(dev))
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return (dev->ifindex != dev->iflink ?
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IF_OPER_LOWERLAYERDOWN : IF_OPER_DOWN);
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if (netif_dormant(dev))
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return IF_OPER_DORMANT;
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return IF_OPER_UP;
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}
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static void rfc2863_policy(struct net_device *dev)
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{
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unsigned char operstate = default_operstate(dev);
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if (operstate == dev->operstate)
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return;
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write_lock_bh(&dev_base_lock);
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switch(dev->link_mode) {
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case IF_LINK_MODE_DORMANT:
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if (operstate == IF_OPER_UP)
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operstate = IF_OPER_DORMANT;
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break;
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case IF_LINK_MODE_DEFAULT:
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default:
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break;
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2007-04-21 00:09:22 +00:00
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}
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2006-03-21 01:09:11 +00:00
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dev->operstate = operstate;
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write_unlock_bh(&dev_base_lock);
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}
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2008-07-09 06:01:06 +00:00
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static bool linkwatch_urgent_event(struct net_device *dev)
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2007-05-09 01:36:28 +00:00
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{
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return netif_running(dev) && netif_carrier_ok(dev) &&
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2008-07-09 06:01:06 +00:00
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qdisc_tx_changing(dev);
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2007-05-09 01:36:28 +00:00
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}
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static void linkwatch_add_event(struct net_device *dev)
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{
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unsigned long flags;
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spin_lock_irqsave(&lweventlist_lock, flags);
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dev->link_watch_next = lweventlist;
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lweventlist = dev;
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spin_unlock_irqrestore(&lweventlist_lock, flags);
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}
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2007-05-09 07:17:30 +00:00
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static void linkwatch_schedule_work(int urgent)
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2007-05-09 01:36:28 +00:00
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{
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2007-05-09 07:17:30 +00:00
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unsigned long delay = linkwatch_nextevent - jiffies;
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if (test_bit(LW_URGENT, &linkwatch_flags))
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2007-05-09 01:36:28 +00:00
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return;
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2007-05-09 07:17:30 +00:00
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/* Minimise down-time: drop delay for up event. */
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if (urgent) {
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if (test_and_set_bit(LW_URGENT, &linkwatch_flags))
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return;
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2007-05-09 01:36:28 +00:00
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delay = 0;
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2007-05-09 06:22:43 +00:00
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}
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2007-05-09 01:36:28 +00:00
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2007-05-09 07:17:30 +00:00
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/* If we wrap around we'll delay it by at most HZ. */
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if (delay > HZ)
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delay = 0;
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/*
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* This is true if we've scheduled it immeditately or if we don't
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* need an immediate execution and it's already pending.
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*/
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if (schedule_delayed_work(&linkwatch_work, delay) == !delay)
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return;
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/* Don't bother if there is nothing urgent. */
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if (!test_bit(LW_URGENT, &linkwatch_flags))
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return;
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/* It's already running which is good enough. */
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if (!cancel_delayed_work(&linkwatch_work))
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return;
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/* Otherwise we reschedule it again for immediate exection. */
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schedule_delayed_work(&linkwatch_work, 0);
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2007-05-09 01:36:28 +00:00
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}
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static void __linkwatch_run_queue(int urgent_only)
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2005-04-16 22:20:36 +00:00
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{
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2007-05-09 01:34:17 +00:00
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struct net_device *next;
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2005-04-16 22:20:36 +00:00
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2007-05-09 01:36:28 +00:00
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/*
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* Limit the number of linkwatch events to one
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* per second so that a runaway driver does not
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* cause a storm of messages on the netlink
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* socket. This limit does not apply to up events
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* while the device qdisc is down.
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*/
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if (!urgent_only)
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linkwatch_nextevent = jiffies + HZ;
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2007-05-09 07:17:30 +00:00
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/* Limit wrap-around effect on delay. */
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else if (time_after(linkwatch_nextevent, jiffies + HZ))
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linkwatch_nextevent = jiffies;
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clear_bit(LW_URGENT, &linkwatch_flags);
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2007-05-09 01:36:28 +00:00
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2005-04-16 22:20:36 +00:00
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spin_lock_irq(&lweventlist_lock);
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2007-05-09 01:34:17 +00:00
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next = lweventlist;
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lweventlist = NULL;
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2005-04-16 22:20:36 +00:00
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spin_unlock_irq(&lweventlist_lock);
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2007-05-09 01:34:17 +00:00
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while (next) {
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struct net_device *dev = next;
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2005-04-16 22:20:36 +00:00
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2007-05-09 01:34:17 +00:00
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next = dev->link_watch_next;
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2007-05-09 01:36:28 +00:00
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if (urgent_only && !linkwatch_urgent_event(dev)) {
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linkwatch_add_event(dev);
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continue;
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}
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2007-05-09 01:34:17 +00:00
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/*
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* Make sure the above read is complete since it can be
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* rewritten as soon as we clear the bit below.
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*/
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smp_mb__before_clear_bit();
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2005-04-16 22:20:36 +00:00
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/* We are about to handle this device,
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* so new events can be accepted
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*/
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clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
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2006-03-21 01:09:11 +00:00
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rfc2863_policy(dev);
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2005-04-16 22:20:36 +00:00
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if (dev->flags & IFF_UP) {
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2008-07-09 06:01:06 +00:00
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if (netif_carrier_ok(dev))
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2005-05-03 23:18:52 +00:00
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dev_activate(dev);
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2008-07-09 06:01:06 +00:00
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else
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2005-05-03 23:18:52 +00:00
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dev_deactivate(dev);
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2005-04-16 22:20:36 +00:00
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netdev_state_change(dev);
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}
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dev_put(dev);
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}
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2007-05-09 01:36:28 +00:00
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if (lweventlist)
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2007-05-09 07:17:30 +00:00
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linkwatch_schedule_work(0);
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2007-02-09 14:24:36 +00:00
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}
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2005-04-16 22:20:36 +00:00
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2007-05-09 01:36:28 +00:00
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/* Must be called with the rtnl semaphore held */
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void linkwatch_run_queue(void)
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2005-04-16 22:20:36 +00:00
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{
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2007-05-09 01:36:28 +00:00
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__linkwatch_run_queue(0);
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}
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2005-04-16 22:20:36 +00:00
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2007-05-09 01:36:28 +00:00
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static void linkwatch_event(struct work_struct *dummy)
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{
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2006-03-21 06:23:58 +00:00
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rtnl_lock();
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2007-05-09 01:36:28 +00:00
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__linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies));
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2006-03-21 06:23:58 +00:00
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rtnl_unlock();
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2005-04-16 22:20:36 +00:00
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}
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void linkwatch_fire_event(struct net_device *dev)
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{
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2008-07-09 06:01:06 +00:00
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bool urgent = linkwatch_urgent_event(dev);
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2005-04-16 22:20:36 +00:00
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2007-05-09 07:17:30 +00:00
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if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {
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2005-04-16 22:20:36 +00:00
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dev_hold(dev);
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2007-05-09 01:36:28 +00:00
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linkwatch_add_event(dev);
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2007-05-09 07:17:30 +00:00
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} else if (!urgent)
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return;
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2005-04-16 22:20:36 +00:00
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2007-05-09 07:17:30 +00:00
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linkwatch_schedule_work(urgent);
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2005-04-16 22:20:36 +00:00
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}
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EXPORT_SYMBOL(linkwatch_fire_event);
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