[PATCH net-next v2 5/6] net/lapb: support netdev events

Martin Schiller
2020-11-16T13:55:26Z

This makes it possible to handle carrier loss and detection.
In case of Carrier Loss, layer 2 is terminated
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@dev.tdt.de>
---

Change from v1:
fix 'subject_prefix' and 'checkpatch' warnings

---
net/lapb/lapb_iface.c | 83 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 83 insertions(+)

diff --git a/net/lapb/lapb_iface.c b/net/lapb/lapb_iface.c
index 3c03f6512c5f..63124cdf1926 100644
--- a/net/lapb/lapb_iface.c
+++ b/net/lapb/lapb_iface.c
@@ -418,14 +418,97 @@ 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 = 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_REGISTER:
+ lapb_dbg(0, "(%p): got event NETDEV_REGISTER for device: %s\n",
+ dev, dev->name);
+ break;
+ case NETDEV_POST_TYPE_CHANGE:
+ lapb_dbg(0, "(%p): got event NETDEV_POST_TYPE_CHANGE for device: %s\n",
+ dev, dev->name);
+ break;
+ case NETDEV_UP:
+ lapb_dbg(0, "(%p): got event NETDEV_UP for device: %s\n",
+ dev, dev->name);
+ break;
+ case NETDEV_GOING_DOWN:
+ lapb_dbg(0, "(%p): got event NETDEV_GOING_DOWN for device: %s\n",
+ dev, dev->name);
+ break;
+ case NETDEV_DOWN:
+ lapb_dbg(0, "(%p): got event NETDEV_DOWN for device: %s\n",
+ dev, dev->name);
+ break;
+ case NETDEV_PRE_TYPE_CHANGE:
+ lapb_dbg(0, "(%p): got event NETDEV_PRE_TYPE_CHANGE for device: %s\n",
+ dev, dev->name);
+ break;
+ case NETDEV_UNREGISTER:
+ lapb_dbg(0, "(%p): got event NETDEV_UNREGISTER for device: %s\n",
+ dev, dev->name);
+ break;
+ case NETDEV_CHANGE:
+ lapb_dbg(0, "(%p): got event NETDEV_CHANGE for device: %s\n",
+ dev, dev->name);
+ lapb = lapb_devtostruct(dev);
+ if (!lapb)
+ break;
+
+ if (!netif_carrier_ok(dev)) {
+ lapb_dbg(0, "(%p): Carrier lost -> Entering LAPB_STATE_0: %s\n",
+ dev, dev->name);
+ lapb_disconnect_indication(lapb, LAPB_OK);
+ lapb_clear_queues(lapb);
+ lapb->state = LAPB_STATE_0;
+ lapb->n2count = 0;
+ lapb_stop_t1timer(lapb);
+ lapb_stop_t2timer(lapb);
+ } else {
+ 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);
+ }
+ }
+ }
+ 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 <g4klx@g4klx.demon.co.uk>");
--
2.20.1