From c161e4df094e3397e749bdb18b9a7e5f230f59f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Simon=20St=C3=BCrz?= <simon.stuerz@nymea.io>
Date: Fri, 5 May 2023 08:49:31 +0200
Subject: [PATCH] NetworkDeviceDiscovery: perform reachability verification
 ping

---
 .../hardware/network/networkdevicediscoveryimpl.cpp        | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libnymea-core/hardware/network/networkdevicediscoveryimpl.cpp b/libnymea-core/hardware/network/networkdevicediscoveryimpl.cpp
index c3379aee..b3cc0370 100644
--- a/libnymea-core/hardware/network/networkdevicediscoveryimpl.cpp
+++ b/libnymea-core/hardware/network/networkdevicediscoveryimpl.cpp
@@ -608,6 +608,13 @@ void NetworkDeviceDiscoveryImpl::evaluateMonitor(NetworkDeviceMonitorImpl *monit
         return;
     }
 
+    if (!requiresRefresh && monitor->reachable() && currentDateTime <= monitor->lastConnectionAttempt().addSecs(m_rediscoveryInterval)) {
+        // Note: in some cases only a failed ping is able to mark a device as offline if some ARP proxy is responding to our ARP requests.
+        // Ping all network devices in any case once in a while, even if we think it is reachable.
+        qCDebug(dcNetworkDeviceDiscovery()) << monitor << "performing verification ping.";
+        requiresRefresh = true;
+    }
+
     if (!requiresRefresh)
         return;