On Tue, 24 Nov 2020 10:39:35 +0100 Martin Schiller wrote:
> This patch allows layer2 (LAPB) to react to netdev events itself and
> avoids the detour via layer3 (X.25).
>
> 1. Establish layer2 on NETDEV_UP events, if the carrier is already up.
>
> 2. Call lapb_disconnect_request() on NETDEV_GOING_DOWN events to signal
> the peer that the connection will go down.
> (Only when the carrier is up.)
>
> 3. When a NETDEV_DOWN event occur, clear all queues, enter state
> LAPB_STATE_0 and stop all timers.
>
> 4. The NETDEV_CHANGE event makes it possible to handle carrier loss and
> detection.
>
> In case of Carrier Loss, clear all queues, enter state LAPB_STATE_0
> and stop all timers.
>
> In case of Carrier Detection, we start timer t1 on a DCE interface,
> and on a DTE interface we change to state LAPB_STATE_1 and start
> sending SABM(E).
>
> Signed-off-by: Martin Schiller <ms@xxxxxxxxxx>
> +/* Handle device status changes. */
> +static int lapb_device_event(struct notifier_block *this, unsigned long event,
> + void *ptr)
> +{
> + struct net_device *dev = netdev_notifier_info_to_dev(ptr);
> + struct lapb_cb *lapb;
> +
> + if (!net_eq(dev_net(dev), &init_net))
> + return NOTIFY_DONE;
> +
> + if (dev->type == ARPHRD_X25) {
Flip condition, save indentation.
if (dev->type != ARPHRD_X25)
return NOTIFY_DONE;
You can also pull out of all the cases:
lapb = lapb_devtostruct(dev);
if (!lapb)
return NOTIFY_DONE;
right?
> + switch (event) {
> + case NETDEV_UP:
> + lapb_dbg(0, "(%p) Interface up: %s\n", dev,
> + dev->name);
> +
> + if (netif_carrier_ok(dev)) {
> + lapb = lapb_devtostruct(dev);
> + if (!lapb)
> + break;
> static int __init lapb_init(void)
> {
> + register_netdevice_notifier(&lapb_dev_notifier);
This can fail, so:
return register_netdevice_notifier(&lapb_dev_notifier);
> return 0;
> }
>
> static void __exit lapb_exit(void)
> {
> WARN_ON(!list_empty(&lapb_list));
> +
> + unregister_netdevice_notifier(&lapb_dev_notifier);
> }
>
> MODULE_AUTHOR("Jonathan Naylor <g4klx@xxxxxxxxxxxxxxxxx>");
