1 files changed, 105 insertions, 0 deletions
diff --git a/notifier.c b/notifier.c
new file mode 100644
index 0000000..7f9712d
--- /dev/null
+++ b/notifier.c
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Wifi performance tracker
+ *
+ * Copyright 2022 Google LLC.
+ *
+ * Author: Star Chang <starchang@google.com>
+ */
+#include "core.h"
+
+#define notifier_to_core(notifier) \
+	container_of(notifier, struct wlan_ptracker_core, notifier)
+
+#define nb_to_notifier(nb) \
+	(container_of(nb, struct wlan_ptracker_notifier, nb))
+
+static int up_event_handler(struct wlan_ptracker_core *core, struct net_device *dev)
+{
+	core->dev = dev;
+	core->client->core = core;
+	core->client->priv = dev;
+	return tp_monitor_init(&core->tp);
+}
+
+static void down_event_handler(struct wlan_ptracker_core *core)
+{
+	tp_monitor_exit(&core->tp);
+	core->dev = NULL;
+	core->client->core = NULL;
+	core->client->priv = NULL;
+}
+
+static int netdevice_notifier_handler(struct notifier_block *nb,
+	unsigned long event, void *ptr)
+{
+	struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
+	struct wlan_ptracker_notifier *notifier = nb_to_notifier(nb);
+	struct wlan_ptracker_core *core = notifier_to_core(notifier);
+
+	if (!core->client)
+		return NOTIFY_DONE;
+
+	if (strcmp(netdev->name, core->client->ifname))
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case NETDEV_UP:
+		ptracker_info(core, "interface up (%s)\n", netdev->name);
+		up_event_handler(core, netdev);
+		break;
+	case NETDEV_DOWN:
+		ptracker_info(core, "interface down (%s)\n", netdev->name);
+		down_event_handler(core);
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+int wlan_ptracker_register_notifier(struct wlan_ptracker_notifier *notifier,
+	struct notifier_block *nb)
+{
+	return  blocking_notifier_chain_register(&notifier->notifier_head, nb);
+}
+
+void wlan_ptracker_unregister_notifier(struct wlan_ptracker_notifier *notifier,
+	struct notifier_block *nb)
+{
+	blocking_notifier_chain_unregister(&notifier->notifier_head, nb);
+}
+
+int wlan_ptracker_call_chain(struct wlan_ptracker_notifier *notifier,
+	unsigned long event, void *priv)
+{
+	struct wlan_ptracker_core *core = priv;
+	int ret;
+
+	ret = blocking_notifier_call_chain(&notifier->notifier_head, event, priv);
+	if (ret & NOTIFY_STOP_MASK)
+		ptracker_err(core, "notifier chain fail with status %#x\n", ret);
+
+	return notifier_to_errno(ret);
+}
+
+void wlan_ptracker_notifier_init(struct wlan_ptracker_notifier *notifier)
+{
+	notifier->prev_event = jiffies;
+	/* register to device notifier */
+	notifier->nb.priority = 0;
+	notifier->nb.notifier_call = netdevice_notifier_handler;
+	register_netdevice_notifier(&notifier->nb);
+	/* init notifier chain to notify plugin modules */
+	BLOCKING_INIT_NOTIFIER_HEAD(&notifier->notifier_head);
+}
+
+void wlan_ptracker_notifier_exit(struct wlan_ptracker_notifier *notifier)
+{
+	/* reset notifier */
+	BLOCKING_INIT_NOTIFIER_HEAD(&notifier->notifier_head);
+	/* unregister netdevice notifier*/
+	unregister_netdevice_notifier(&notifier->nb);
+	notifier->prev_event = 0;
+}
+