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 <m...@dev.tdt.de>
---
net/lapb/lapb_iface.c | 94 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 94 insertions(+)
diff --git a/net/lapb/lapb_iface.c b/net/lapb/lapb_iface.c
index 3c03f6512c5f..f226d354aaf0 100644
--- a/net/lapb/lapb_iface.c
+++ b/net/lapb/lapb_iface.c
@@ -418,14 +418,108 @@ int lapb_data_transmit(struct lapb_cb *lapb, struct
sk_buff *skb)
return used;
}
+/* 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) {
+ 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;
+
+ lapb_dbg(0, "(%p): Carrier is already up: %s\n",
+ dev, dev->name);
+ if (lapb->mode & LAPB_DCE) {
+ lapb_start_t1timer(lapb);
+ } else {
+ if (lapb->state == LAPB_STATE_0) {
+ lapb->state = LAPB_STATE_1;
+ lapb_establish_data_link(lapb);
+ }
+ }
+ }
+ break;
+ case NETDEV_GOING_DOWN:
+ if (netif_carrier_ok(dev))
+ lapb_disconnect_request(dev);
+ break;
+ case NETDEV_DOWN:
+ lapb = lapb_devtostruct(dev);
+ if (!lapb)
+ break;
+
+ lapb_dbg(0, "(%p) Interface down: %s\n", dev,
+ dev->name);
+ lapb_dbg(0, "(%p) S%d -> S0\n", dev,
+ lapb->state);
+ lapb_clear_queues(lapb);
+ lapb->state = LAPB_STATE_0;
+ lapb->n2count = 0;
+ lapb_stop_t1timer(lapb);
+ lapb_stop_t2timer(lapb);
+ break;
+ case NETDEV_CHANGE:
+ lapb = lapb_devtostruct(dev);
+ if (!lapb)
+ break;
+
+ if (netif_carrier_ok(dev)) {
+ lapb_dbg(0, "(%p): Carrier detected: %s\n",
+ dev, dev->name);
+ if (lapb->mode & LAPB_DCE) {
+ lapb_start_t1timer(lapb);
+ } else {
+ if (lapb->state == LAPB_STATE_0) {
+ lapb->state = LAPB_STATE_1;
+ lapb_establish_data_link(lapb);
+ }
+ }
+ } else {
+ lapb_dbg(0, "(%p) Carrier lost: %s\n", dev,
+ dev->name);
+ lapb_dbg(0, "(%p) S%d -> S0\n", dev,
+ lapb->state);
+ lapb_clear_queues(lapb);
+ lapb->state = LAPB_STATE_0;
+ lapb->n2count = 0;
+ lapb_stop_t1timer(lapb);
+ lapb_stop_t2timer(lapb);
+ }
+ break;
+ }
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block lapb_dev_notifier = {
+ .notifier_call = lapb_device_event,
+};
+
static int __init lapb_init(void)
{
+ 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 <g4...@g4klx.demon.co.uk>");
--
2.20.1
