From 103eeb2cc6c398b60bec2263c7e98bde550714df Mon Sep 17 00:00:00 2001
From: James Prestwood <prestwoj@gmail.com>
Date: Tue, 9 Aug 2022 16:04:25 -0700
Subject: [PATCH] station: react to (new) netdev packet loss event

This adds a new netdev event for packet loss notifications from
the kernel. Depending on the scenario a station may see packet
loss events without any other indications like low RSSI. In these
cases IWD should still roam since there is no data flowing.
---
 src/netdev.h  |  1 +
 src/station.c | 39 +++++++++++++++++++++++++++++++++------
 2 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/src/netdev.h b/src/netdev.h
index f093c499..d13bc5e6 100644
--- a/src/netdev.h
+++ b/src/netdev.h
@@ -49,6 +49,7 @@ enum netdev_event {
 	NETDEV_EVENT_RSSI_THRESHOLD_LOW,
 	NETDEV_EVENT_RSSI_THRESHOLD_HIGH,
 	NETDEV_EVENT_RSSI_LEVEL_NOTIFY,
+	NETDEV_EVENT_PACKET_LOSS_NOTIFY,
 };
 
 enum netdev_watch_event {
diff --git a/src/station.c b/src/station.c
index 38909c98..66b296b8 100644
--- a/src/station.c
+++ b/src/station.c
@@ -2535,15 +2535,10 @@ static void station_neighbor_report_cb(struct netdev *netdev, int err,
 		station_roam_failed(station);
 }
 
-static void station_roam_trigger_cb(struct l_timeout *timeout, void *user_data)
+static void station_start_roam(struct station *station)
 {
-	struct station *station = user_data;
 	int r;
 
-	l_debug("%u", netdev_get_ifindex(station->netdev));
-
-	l_timeout_remove(station->roam_trigger_timeout);
-	station->roam_trigger_timeout = NULL;
 	station->preparing_roam = true;
 
 	/*
@@ -2577,6 +2572,18 @@ static void station_roam_trigger_cb(struct l_timeout *timeout, void *user_data)
 		station_roam_failed(station);
 }
 
+static void station_roam_trigger_cb(struct l_timeout *timeout, void *user_data)
+{
+	struct station *station = user_data;
+
+	l_debug("%u", netdev_get_ifindex(station->netdev));
+
+	l_timeout_remove(station->roam_trigger_timeout);
+	station->roam_trigger_timeout = NULL;
+
+	station_start_roam(station);
+}
+
 static void station_roam_timeout_rearm(struct station *station, int seconds)
 {
 	struct timespec now, min_timeout;
@@ -3057,6 +3064,23 @@ static void station_disconnect_event(struct station *station, void *event_data)
 	l_warn("Unexpected disconnect event");
 }
 
+#define STATION_PKT_LOSS_THRESHOLD 10
+
+static void station_packets_lost(struct station *station, uint32_t num_pkts)
+{
+	l_debug("Packets lost event: %u", num_pkts);
+
+	if (num_pkts < STATION_PKT_LOSS_THRESHOLD)
+		return;
+
+	if (station_cannot_roam(station))
+		return;
+
+	station_debug_event(station, "packet-loss-roam");
+
+	station_start_roam(station);
+}
+
 static void station_netdev_event(struct netdev *netdev, enum netdev_event event,
 					void *event_data, void *user_data)
 {
@@ -3092,6 +3116,9 @@ static void station_netdev_event(struct netdev *netdev, enum netdev_event event,
 	case NETDEV_EVENT_CHANNEL_SWITCHED:
 		station_event_channel_switched(station, l_get_u32(event_data));
 		break;
+	case NETDEV_EVENT_PACKET_LOSS_NOTIFY:
+		station_packets_lost(station, l_get_u32(event_data));
+		break;
 	}
 }