From dffbef0dc9f999bf5d03a675b4b868fd980f5f5b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Simon=20St=C3=BCrz?= <simon.stuerz@nymea.io>
Date: Wed, 28 Aug 2024 15:18:41 +0200
Subject: [PATCH] SMA: Fix circular disovery on multiple interfaces in the same
 network
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Signed-off-by: Simon Stürz <simon.stuerz@nymea.io>
---
 sma/speedwire/speedwireinterface.cpp | 31 ++++++++++++++++++++++++++++
 sma/speedwire/speedwireinterface.h   |  2 ++
 2 files changed, 33 insertions(+)

diff --git a/sma/speedwire/speedwireinterface.cpp b/sma/speedwire/speedwireinterface.cpp
index 08ae14e..c4356f8 100644
--- a/sma/speedwire/speedwireinterface.cpp
+++ b/sma/speedwire/speedwireinterface.cpp
@@ -72,6 +72,10 @@ SpeedwireInterface::SpeedwireInterface(quint32 sourceSerialNumber, QObject *pare
             datagram.resize(m_multicast->pendingDatagramSize());
             m_multicast->readDatagram(datagram.data(), datagram.size(), &senderAddress, &senderPort);
 
+            // Filter our own requests on the multicast
+            if (isOwnInterface(senderAddress))
+                return;
+
             qCDebug(dcSma()).noquote() << "SpeedwireInterface: Multicast socket received data from" << QString("%1:%2").arg(senderAddress.toString()).arg(senderPort);
             //qCDebug(dcSma()) << "SpeedwireInterface: " << datagram.toHex();
             emit dataReceived(senderAddress, senderPort, datagram, true);
@@ -111,6 +115,33 @@ bool SpeedwireInterface::available() const
     return m_available;
 }
 
+bool SpeedwireInterface::isOwnInterface(const QHostAddress &hostAddress)
+{
+    foreach (const QNetworkInterface &networkInterface, QNetworkInterface::allInterfaces()) {
+        if (networkInterface.flags().testFlag(QNetworkInterface::IsLoopBack))
+            continue;
+
+        if (!networkInterface.flags().testFlag(QNetworkInterface::IsUp))
+            continue;
+
+        if (!networkInterface.flags().testFlag(QNetworkInterface::IsRunning))
+            continue;
+
+        foreach (const QNetworkAddressEntry &entry, networkInterface.addressEntries()) {
+
+            // Only IPv4
+            if (entry.ip().protocol() != QAbstractSocket::IPv4Protocol)
+                continue;
+
+            if (entry.ip() == hostAddress) {
+                return true;
+            }
+        }
+    }
+
+    return false;
+}
+
 void SpeedwireInterface::reconfigureMulticastGroup()
 {
     qCDebug(dcSma()) << "Reconfigure multicast interfaces";
diff --git a/sma/speedwire/speedwireinterface.h b/sma/speedwire/speedwireinterface.h
index 566e4aa..630883a 100644
--- a/sma/speedwire/speedwireinterface.h
+++ b/sma/speedwire/speedwireinterface.h
@@ -48,6 +48,8 @@ public:
 
     bool available() const;
 
+    static bool isOwnInterface(const QHostAddress &hostAddress);
+
     quint32 sourceSerialNumber() const;
 
     bool initialize();