280 lines
6.2 KiB
C
280 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* Linux network device link state notification
|
|
*
|
|
* Author:
|
|
* Stefan Rompf <sux@loplof.de>
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/netdevice.h>
|
|
#include <linux/if.h>
|
|
#include <net/sock.h>
|
|
#include <net/pkt_sched.h>
|
|
#include <linux/rtnetlink.h>
|
|
#include <linux/jiffies.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/workqueue.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/types.h>
|
|
|
|
|
|
enum lw_bits {
|
|
LW_URGENT = 0,
|
|
};
|
|
|
|
static unsigned long linkwatch_flags;
|
|
static unsigned long linkwatch_nextevent;
|
|
|
|
static void linkwatch_event(struct work_struct *dummy);
|
|
static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event);
|
|
|
|
static LIST_HEAD(lweventlist);
|
|
static DEFINE_SPINLOCK(lweventlist_lock);
|
|
|
|
static unsigned char default_operstate(const struct net_device *dev)
|
|
{
|
|
if (netif_testing(dev))
|
|
return IF_OPER_TESTING;
|
|
|
|
if (!netif_carrier_ok(dev))
|
|
return (dev->ifindex != dev_get_iflink(dev) ?
|
|
IF_OPER_LOWERLAYERDOWN : IF_OPER_DOWN);
|
|
|
|
if (netif_dormant(dev))
|
|
return IF_OPER_DORMANT;
|
|
|
|
return IF_OPER_UP;
|
|
}
|
|
|
|
|
|
static void rfc2863_policy(struct net_device *dev)
|
|
{
|
|
unsigned char operstate = default_operstate(dev);
|
|
|
|
if (operstate == dev->operstate)
|
|
return;
|
|
|
|
write_lock(&dev_base_lock);
|
|
|
|
switch(dev->link_mode) {
|
|
case IF_LINK_MODE_TESTING:
|
|
if (operstate == IF_OPER_UP)
|
|
operstate = IF_OPER_TESTING;
|
|
break;
|
|
|
|
case IF_LINK_MODE_DORMANT:
|
|
if (operstate == IF_OPER_UP)
|
|
operstate = IF_OPER_DORMANT;
|
|
break;
|
|
case IF_LINK_MODE_DEFAULT:
|
|
default:
|
|
break;
|
|
}
|
|
|
|
dev->operstate = operstate;
|
|
|
|
write_unlock(&dev_base_lock);
|
|
}
|
|
|
|
|
|
void linkwatch_init_dev(struct net_device *dev)
|
|
{
|
|
/* Handle pre-registration link state changes */
|
|
if (!netif_carrier_ok(dev) || netif_dormant(dev) ||
|
|
netif_testing(dev))
|
|
rfc2863_policy(dev);
|
|
}
|
|
|
|
|
|
static bool linkwatch_urgent_event(struct net_device *dev)
|
|
{
|
|
if (!netif_running(dev))
|
|
return false;
|
|
|
|
if (dev->ifindex != dev_get_iflink(dev))
|
|
return true;
|
|
|
|
if (netif_is_lag_port(dev) || netif_is_lag_master(dev))
|
|
return true;
|
|
|
|
return netif_carrier_ok(dev) && qdisc_tx_changing(dev);
|
|
}
|
|
|
|
|
|
static void linkwatch_add_event(struct net_device *dev)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&lweventlist_lock, flags);
|
|
if (list_empty(&dev->link_watch_list)) {
|
|
list_add_tail(&dev->link_watch_list, &lweventlist);
|
|
dev_hold_track(dev, &dev->linkwatch_dev_tracker, GFP_ATOMIC);
|
|
}
|
|
spin_unlock_irqrestore(&lweventlist_lock, flags);
|
|
}
|
|
|
|
|
|
static void linkwatch_schedule_work(int urgent)
|
|
{
|
|
unsigned long delay = linkwatch_nextevent - jiffies;
|
|
|
|
if (test_bit(LW_URGENT, &linkwatch_flags))
|
|
return;
|
|
|
|
/* Minimise down-time: drop delay for up event. */
|
|
if (urgent) {
|
|
if (test_and_set_bit(LW_URGENT, &linkwatch_flags))
|
|
return;
|
|
delay = 0;
|
|
}
|
|
|
|
/* If we wrap around we'll delay it by at most HZ. */
|
|
if (delay > HZ)
|
|
delay = 0;
|
|
|
|
/*
|
|
* If urgent, schedule immediate execution; otherwise, don't
|
|
* override the existing timer.
|
|
*/
|
|
if (test_bit(LW_URGENT, &linkwatch_flags))
|
|
mod_delayed_work(system_wq, &linkwatch_work, 0);
|
|
else
|
|
schedule_delayed_work(&linkwatch_work, delay);
|
|
}
|
|
|
|
|
|
static void linkwatch_do_dev(struct net_device *dev)
|
|
{
|
|
/*
|
|
* Make sure the above read is complete since it can be
|
|
* rewritten as soon as we clear the bit below.
|
|
*/
|
|
smp_mb__before_atomic();
|
|
|
|
/* We are about to handle this device,
|
|
* so new events can be accepted
|
|
*/
|
|
clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
|
|
|
|
rfc2863_policy(dev);
|
|
if (dev->flags & IFF_UP) {
|
|
if (netif_carrier_ok(dev))
|
|
dev_activate(dev);
|
|
else
|
|
dev_deactivate(dev);
|
|
|
|
netdev_state_change(dev);
|
|
}
|
|
/* Note: our callers are responsible for calling netdev_tracker_free().
|
|
* This is the reason we use __dev_put() instead of dev_put().
|
|
*/
|
|
__dev_put(dev);
|
|
}
|
|
|
|
static void __linkwatch_run_queue(int urgent_only)
|
|
{
|
|
#define MAX_DO_DEV_PER_LOOP 100
|
|
|
|
int do_dev = MAX_DO_DEV_PER_LOOP;
|
|
struct net_device *dev;
|
|
LIST_HEAD(wrk);
|
|
|
|
/* Give urgent case more budget */
|
|
if (urgent_only)
|
|
do_dev += MAX_DO_DEV_PER_LOOP;
|
|
|
|
/*
|
|
* Limit the number of linkwatch events to one
|
|
* per second so that a runaway driver does not
|
|
* cause a storm of messages on the netlink
|
|
* socket. This limit does not apply to up events
|
|
* while the device qdisc is down.
|
|
*/
|
|
if (!urgent_only)
|
|
linkwatch_nextevent = jiffies + HZ;
|
|
/* Limit wrap-around effect on delay. */
|
|
else if (time_after(linkwatch_nextevent, jiffies + HZ))
|
|
linkwatch_nextevent = jiffies;
|
|
|
|
clear_bit(LW_URGENT, &linkwatch_flags);
|
|
|
|
spin_lock_irq(&lweventlist_lock);
|
|
list_splice_init(&lweventlist, &wrk);
|
|
|
|
while (!list_empty(&wrk) && do_dev > 0) {
|
|
|
|
dev = list_first_entry(&wrk, struct net_device, link_watch_list);
|
|
list_del_init(&dev->link_watch_list);
|
|
|
|
if (!netif_device_present(dev) ||
|
|
(urgent_only && !linkwatch_urgent_event(dev))) {
|
|
list_add_tail(&dev->link_watch_list, &lweventlist);
|
|
continue;
|
|
}
|
|
/* We must free netdev tracker under
|
|
* the spinlock protection.
|
|
*/
|
|
netdev_tracker_free(dev, &dev->linkwatch_dev_tracker);
|
|
spin_unlock_irq(&lweventlist_lock);
|
|
linkwatch_do_dev(dev);
|
|
do_dev--;
|
|
spin_lock_irq(&lweventlist_lock);
|
|
}
|
|
|
|
/* Add the remaining work back to lweventlist */
|
|
list_splice_init(&wrk, &lweventlist);
|
|
|
|
if (!list_empty(&lweventlist))
|
|
linkwatch_schedule_work(0);
|
|
spin_unlock_irq(&lweventlist_lock);
|
|
}
|
|
|
|
void linkwatch_forget_dev(struct net_device *dev)
|
|
{
|
|
unsigned long flags;
|
|
int clean = 0;
|
|
|
|
spin_lock_irqsave(&lweventlist_lock, flags);
|
|
if (!list_empty(&dev->link_watch_list)) {
|
|
list_del_init(&dev->link_watch_list);
|
|
clean = 1;
|
|
/* We must release netdev tracker under
|
|
* the spinlock protection.
|
|
*/
|
|
netdev_tracker_free(dev, &dev->linkwatch_dev_tracker);
|
|
}
|
|
spin_unlock_irqrestore(&lweventlist_lock, flags);
|
|
if (clean)
|
|
linkwatch_do_dev(dev);
|
|
}
|
|
|
|
|
|
/* Must be called with the rtnl semaphore held */
|
|
void linkwatch_run_queue(void)
|
|
{
|
|
__linkwatch_run_queue(0);
|
|
}
|
|
|
|
|
|
static void linkwatch_event(struct work_struct *dummy)
|
|
{
|
|
rtnl_lock();
|
|
__linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies));
|
|
rtnl_unlock();
|
|
}
|
|
|
|
|
|
void linkwatch_fire_event(struct net_device *dev)
|
|
{
|
|
bool urgent = linkwatch_urgent_event(dev);
|
|
|
|
if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {
|
|
linkwatch_add_event(dev);
|
|
} else if (!urgent)
|
|
return;
|
|
|
|
linkwatch_schedule_work(urgent);
|
|
}
|
|
EXPORT_SYMBOL(linkwatch_fire_event);
|