From 42675ae770ad79920f7914265c33cdf279b12ff6 Mon Sep 17 00:00:00 2001
From: Phil Taylor <phil@m0vse.uk>
Date: Mon, 15 Nov 2021 19:28:44 +0000
Subject: [PATCH] Add mutex for incoming audio on udp and server

---
 udphandler.cpp | 58 ++++++++++++++++++++++++++++----------------------
 udphandler.h   |  3 +++
 udpserver.cpp  | 26 ++++++++++++++--------
 udpserver.h    |  1 +
 4 files changed, 54 insertions(+), 34 deletions(-)

diff --git a/udphandler.cpp b/udphandler.cpp
index c0c93e9..6ae6333 100644
--- a/udphandler.cpp
+++ b/udphandler.cpp
@@ -856,36 +856,44 @@ void udpAudio::sendTxAudio()
         return;
     }
     QByteArray audio;
-    txaudio->getNextAudioChunk(audio);
+    if (audioMutex.try_lock_for(std::chrono::milliseconds(LOCK_PERIOD)))
+    {
+        txaudio->getNextAudioChunk(audio);
+        // Now we have the next audio chunk, we can release the mutex.
+        audioMutex.unlock();
 
-    if (audio.length() > 0) {
-        int counter = 1;
-        int len = 0;
+        if (audio.length() > 0) {
+            int counter = 1;
+            int len = 0;
 
-        while (len < audio.length()) {
-            QByteArray partial = audio.mid(len, 1364);
-            audio_packet p;
-            memset(p.packet, 0x0, sizeof(p)); // We can't be sure it is initialized with 0x00!
-            p.len = sizeof(p) + partial.length();
-            p.sentid = myId;
-            p.rcvdid = remoteId;
-            if (partial.length() == 0xa0) {
-                p.ident = 0x9781;
+            while (len < audio.length()) {
+                QByteArray partial = audio.mid(len, 1364);
+                audio_packet p;
+                memset(p.packet, 0x0, sizeof(p)); // We can't be sure it is initialized with 0x00!
+                p.len = sizeof(p) + partial.length();
+                p.sentid = myId;
+                p.rcvdid = remoteId;
+                if (partial.length() == 0xa0) {
+                    p.ident = 0x9781;
+                }
+                else {
+                    p.ident = 0x0080; // TX audio is always this?
+                }
+                p.datalen = (quint16)qToBigEndian((quint16)partial.length());
+                p.sendseq = (quint16)qToBigEndian((quint16)sendAudioSeq); // THIS IS BIG ENDIAN!
+                QByteArray tx = QByteArray::fromRawData((const char*)p.packet, sizeof(p));
+                tx.append(partial);
+                len = len + partial.length();
+                //qInfo(logUdp()) << "Sending audio packet length: " << tx.length();
+                sendTrackedPacket(tx);
+                sendAudioSeq++;
+                counter++;
             }
-            else {
-                p.ident = 0x0080; // TX audio is always this?
-            }
-            p.datalen = (quint16)qToBigEndian((quint16)partial.length());
-            p.sendseq = (quint16)qToBigEndian((quint16)sendAudioSeq); // THIS IS BIG ENDIAN!
-            QByteArray tx = QByteArray::fromRawData((const char*)p.packet, sizeof(p));
-            tx.append(partial);
-            len = len + partial.length();
-            //qInfo(logUdp()) << "Sending audio packet length: " << tx.length();
-            sendTrackedPacket(tx);
-            sendAudioSeq++;
-            counter++;
         }
     }
+    else {
+        qInfo(logUdpServer()) << "Unable to lock mutex for rxaudio";
+    }
 }
 
 void udpAudio::changeLatency(quint16 value)
diff --git a/udphandler.h b/udphandler.h
index c16bc4a..1a8e975 100644
--- a/udphandler.h
+++ b/udphandler.h
@@ -32,6 +32,7 @@
 #define AREYOUTHERE_PERIOD 500
 #define WATCHDOG_PERIOD 500
 #define RETRANSMIT_PERIOD 100
+#define LOCK_PERIOD 100
 
 struct udpPreferences {
 	QString ipAddress;
@@ -197,6 +198,8 @@ private:
 	QTimer* txAudioTimer=Q_NULLPTR;
 	bool enableTx = true;
 
+	QMutex audioMutex;
+
 };
 
 
diff --git a/udpserver.cpp b/udpserver.cpp
index 30208eb..9f6527c 100644
--- a/udpserver.cpp
+++ b/udpserver.cpp
@@ -159,7 +159,7 @@ void udpServer::controlReceived()
             current->commonCap = 0x8010;
             qInfo(logUdpServer()) << current->ipAddress.toString() << ": New Control connection created";
 
-            if (connMutex.try_lock_for(std::chrono::milliseconds(LOCK_PERIOD))) 
+            if (connMutex.try_lock_for(std::chrono::milliseconds(LOCK_PERIOD)))
             {
                 controlClients.append(current);
                 connMutex.unlock();
@@ -1469,14 +1469,22 @@ void udpServer::sendRxAudio()
 {
     QByteArray audio;
     if (rxaudio) {
-        audio.clear();
-        rxaudio->getNextAudioChunk(audio);
-        int len = 0;
-        while (len < audio.length()) {
-            audioPacket partial;
-            partial.data = audio.mid(len, 1364);
-            receiveAudioData(partial);
-            len = len + partial.data.length();
+        if (audioMutex.try_lock_for(std::chrono::milliseconds(LOCK_PERIOD)))
+        {
+            audio.clear();
+            rxaudio->getNextAudioChunk(audio);
+            // Now we have the next audio chunk, we can release the mutex.
+            audioMutex.unlock();
+            int len = 0;
+            while (len < audio.length()) {
+                audioPacket partial;
+                partial.data = audio.mid(len, 1364);
+                receiveAudioData(partial);
+                len = len + partial.data.length();
+            }
+        }
+        else {
+            qInfo(logUdpServer()) << "Unable to lock mutex for rxaudio";
         }
     }
 }
diff --git a/udpserver.h b/udpserver.h
index 90bfcda..1bfbacd 100644
--- a/udpserver.h
+++ b/udpserver.h
@@ -154,6 +154,7 @@ private:
 
 	QMutex udpMutex; // Used for critical operations.
 	QMutex connMutex;
+	QMutex audioMutex;
 
 	QList <CLIENT*> controlClients = QList<CLIENT*>();
 	QList <CLIENT*> civClients = QList<CLIENT*>();