Ensures that any leftover cached LDU1 message is reset when the call ends.

244 Prevent P25 Encrypted Audio Decoding/Playback

build/build.xml

@@ -7,7 +7,7 @@
   <property name="major" value="0"/>
   <property name="minor" value="3"/>
   <property name="patch" value="0"/>
-  <property name="release" value="-beta10"/>
+  <property name="release" value="-beta12"/>
   <property name="filename" value="sdrtrunk_${major}.${minor}.${patch}${release}"/>
     
   <!-- Build properties -->

src/module/ProcessingChain.java

@@ -320,7 +320,13 @@ public class ProcessingChain implements IChannelEventListener
 
         if(module instanceof IFrequencyChangeListener)
         {
-            mFrequencyChangeEventBroadcaster.addListener(((IFrequencyChangeListener) module).getFrequencyChangeListener());
+            Listener<FrequencyChangeEvent> frequencyChangeEventListener =
+                ((IFrequencyChangeListener)module).getFrequencyChangeListener();
+
+            if(frequencyChangeEventListener != null)
+            {
+                mFrequencyChangeEventBroadcaster.addListener(frequencyChangeEventListener);
+            }
         }
 
         if(module instanceof IMessageListener)

src/module/decode/p25/P25DecoderState.java

@@ -421,7 +421,7 @@ public class P25DecoderState extends DecoderState
                 mCurrentCallEvent = new P25CallEvent.Builder(CallEventType.CALL)
                     .aliasList(getAliasList())
                     .channel(mCurrentChannel)
-                    .details((hdu.isEncrypted() ? "ENCRYPTED " : ""))
+                    .details((hdu.isEncryptedAudio() ? "ENCRYPTED " : ""))
                     .frequency(mCurrentChannelFrequency)
                     .to(to)
                     .build();
@@ -1107,7 +1107,7 @@ public class P25DecoderState extends DecoderState
                                 broadcast(new P25CallEvent.Builder(CallEventType.CALL_DETECT)
                                     .aliasList(getAliasList())
                                     .channel(gvcu.getChannelA())
-                                    .details((gvcu.isEncrypted() ? "ENCRYPTED" : ""))
+                                    .details((gvcu.isEncryptedLinkControlWord() ? "ENCRYPTED" : ""))
                                     .frequency(gvcu.getDownlinkFrequencyA())
                                     .to(userA)
                                     .build());
@@ -1122,7 +1122,7 @@ public class P25DecoderState extends DecoderState
                                 broadcast(new P25CallEvent.Builder(CallEventType.CALL_DETECT)
                                     .aliasList(getAliasList())
                                     .channel(gvcu.getChannelB())
-                                    .details((gvcu.isEncrypted() ? "ENCRYPTED" : ""))
+                                    .details((gvcu.isEncryptedLinkControlWord() ? "ENCRYPTED" : ""))
                                     .frequency(gvcu.getDownlinkFrequencyB())
                                     .to(userB)
                                     .build());
@@ -1151,7 +1151,7 @@ public class P25DecoderState extends DecoderState
                                 broadcast(new P25CallEvent.Builder(CallEventType.CALL_DETECT)
                                     .aliasList(getAliasList())
                                     .channel(gvcue.getTransmitChannel())
-                                    .details((gvcue.isEncrypted() ? "ENCRYPTED" : ""))
+                                    .details((gvcue.isEncryptedLinkControlWord() ? "ENCRYPTED" : ""))
                                     .frequency(gvcue.getDownlinkFrequency())
                                     .to(group)
                                     .build());
@@ -1187,7 +1187,7 @@ public class P25DecoderState extends DecoderState
                             if(mCurrentCallEvent.getDetails() == null)
                             {
                                 mCurrentCallEvent.setDetails(
-                                    (gvcuser.isEncrypted() ? "ENCRYPTED " : "") +
+                                    (gvcuser.isEncryptedLinkControlWord() ? "ENCRYPTED " : "") +
                                         (gvcuser.isEmergency() ? "EMERGENCY " : ""));
 
                                 broadcast(mCurrentCallEvent);
@@ -1399,7 +1399,7 @@ public class P25DecoderState extends DecoderState
                         if(mCurrentCallEvent.getDetails() == null)
                         {
                             mCurrentCallEvent.setDetails(
-                                (tivcu.isEncrypted() ? "ENCRYPTED " : "") +
+                                (tivcu.isEncryptedLinkControlWord() ? "ENCRYPTED " : "") +
                                     (tivcu.isEmergency() ? "EMERGENCY " : ""));
 
                             broadcast(mCurrentCallEvent);
@@ -1482,7 +1482,7 @@ public class P25DecoderState extends DecoderState
                         if(mCurrentCallEvent.getDetails() == null)
                         {
                             mCurrentCallEvent.setDetails(
-                                (uuvcu.isEncrypted() ? "ENCRYPTED " : "") +
+                                (uuvcu.isEncryptedLinkControlWord() ? "ENCRYPTED " : "") +
                                     (uuvcu.isEmergency() ? "EMERGENCY " : ""));
 
                             broadcast(mCurrentCallEvent);

src/module/decode/p25/audio/P25AudioModule.java

@@ -12,6 +12,9 @@ import jmbe.iface.AudioConverter;
 import message.IMessageListener;
 import message.Message;
 import module.Module;
+import module.decode.p25.message.hdu.HDUMessage;
+import module.decode.p25.message.ldu.LDU1Message;
+import module.decode.p25.message.ldu.LDU2Message;
 import module.decode.p25.message.ldu.LDUMessage;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -25,14 +28,18 @@ public class P25AudioModule extends Module implements Listener<Message>, IAudioP
     private final static Logger mLog = LoggerFactory.getLogger(P25AudioModule.class);
 
     private static final String IMBE_CODEC = "IMBE";
-
     private static boolean mLibraryLoadStatusLogged = false;
+
     private boolean mCanConvertAudio = false;
+    private boolean mEncryptedCall = false;
+    private boolean mEncryptedCallStateEstablished = false;
+
     private AudioConverter mAudioConverter;
     private Listener<AudioPacket> mAudioPacketListener;
     private SquelchStateListener mSquelchStateListener = new SquelchStateListener();
     private NonClippingGain mGain = new NonClippingGain(5.0f, 0.95f);
     private Metadata mMetadata;
+    private LDU1Message mCachedLDU1Message = null;
 
     public P25AudioModule(Metadata metadata)
     {
@@ -76,21 +83,60 @@ public class P25AudioModule extends Module implements Listener<Message>, IAudioP
     }
 
     /**
-     * Primary processing method for p25 imbe audio frame messages.  Each LDU
+     * Processes call header (HDU) and voice frame (LDU1/LDU2) messages to decode audio and to determine the
-     * audio message contains 9 imbe voice frames.  Each frame is converted to
+     * encrypted audio status of a call event. Only the HDU and LDU2 messages convey encrypted call status. If an
-     * audio when the JMBE library is loaded, processed by auto-gain, and
+     * LDU1 message is received without a preceding HDU message, then the LDU1 message is cached until the first
-     * broadcast to the audio packet listener.
+     * LDU2 message is received and the encryption state can be determined. Both the LDU1 and the LDU2 message are
+     * then processed for audio if the call is unencrypted.
      */
     public void receive(Message message)
     {
         if(mCanConvertAudio && mAudioPacketListener != null)
+        {
+            if(mEncryptedCallStateEstablished)
             {
                 if(message instanceof LDUMessage)
                 {
-                LDUMessage ldu = (LDUMessage) message;
+                    processAudio((LDUMessage)message);
+                }
+            }
+            else
+            {
+                if(message instanceof HDUMessage)
+                {
+                    mEncryptedCallStateEstablished = true;
+                    mEncryptedCall = ((HDUMessage)message).isEncryptedAudio();
+                }
+                else if(message instanceof LDU1Message)
+                {
+                    //When we receive an LDU1 message with first receiving the HDU message, cache the LDU1 Message
+                    //until we can determine the encrypted call state from the next LDU2 message
+                    mCachedLDU1Message = (LDU1Message)message;
+                }
+                else if(message instanceof LDU2Message)
+                {
+                    mEncryptedCallStateEstablished = true;
+                    LDU2Message ldu2 = (LDU2Message)message;
+                    mEncryptedCall = ldu2.isEncryptedAudio();
 
-				/* Only process unencrypted audio frames */
+                    if(mCachedLDU1Message != null)
-                if (!(ldu.isValid() && ldu.isEncrypted()))
+                    {
+                        processAudio(mCachedLDU1Message);
+                        mCachedLDU1Message = null;
+                    }
+
+                    processAudio(ldu2);
+                }
+            }
+        }
+    }
+
+    /**
+     * Processes an audio packet by decoding the IMBE audio frames and rebroadcasting them as PCM audio packets.
+     */
+    private void processAudio(LDUMessage ldu)
+    {
+        if(!mEncryptedCall)
         {
             for(byte[] frame : ldu.getIMBEFrames())
             {
@@ -101,7 +147,9 @@ public class P25AudioModule extends Module implements Listener<Message>, IAudioP
                 mAudioPacketListener.receive(new AudioPacket(audio, mMetadata.copyOf()));
             }
         }
-            }
+        else
+        {
+            //Encrypted audio processing not implemented
         }
     }
 
@@ -196,20 +244,26 @@ public class P25AudioModule extends Module implements Listener<Message>, IAudioP
     }
 
     /**
-     * Wrapper for squelch state listener.  Internally, the P25 audio module
+     * Wrapper for squelch state to process end of call actions.  At call end the encrypted call state established
-     * doesn't have a squelch state.  If there are IMBE audio frames, we have
+     * flag is reset so that the encrypted audio state for the next call can be properly detected and we send an
-     * audio.  We use this listener to signal to the recorder manager that the
+     * END audio packet so that downstream processors like the audio recorder can properly close out a call sequence.
-     * channel state is resetting and it should end the recording.
      */
     public class SquelchStateListener implements Listener<SquelchState>
     {
         @Override
         public void receive(SquelchState state)
         {
-            if (state == SquelchState.SQUELCH && mAudioPacketListener != null)
+            if(state == SquelchState.SQUELCH)
+            {
+                if(mAudioPacketListener != null)
                 {
                     mAudioPacketListener.receive(new AudioPacket(AudioPacket.Type.END, mMetadata.copyOf()));
                 }
+
+                mEncryptedCallStateEstablished = false;
+                mEncryptedCall = false;
+                mCachedLDU1Message = null;
+            }
         }
     }
 }

src/module/decode/p25/message/hdu/HDUMessage.java

@@ -245,7 +245,7 @@ public class HDUMessage extends P25Message
 		return Encryption.fromValue( mMessage.getInt( ALGORITHM_ID ) );
 	}
 	
-	public boolean isEncrypted()
+	public boolean isEncryptedAudio()
 	{
 		return getEncryption() != Encryption.UNENCRYPTED;
 	}

src/module/decode/p25/message/ldu/LDU1Message.java

@@ -1,24 +1,22 @@
 package module.decode.p25.message.ldu;
 
-import module.decode.p25.reference.DataUnitID;
-import module.decode.p25.reference.LinkControlOpcode;
-import module.decode.p25.reference.Vendor;
-import module.decode.p25.reference.VendorLinkControlOpcode;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import alias.AliasList;
 import bits.BinaryMessage;
 import edac.CRC;
 import edac.Hamming10;
 import edac.ReedSolomon_63_47_17;
+import module.decode.p25.reference.DataUnitID;
+import module.decode.p25.reference.LinkControlOpcode;
+import module.decode.p25.reference.Vendor;
+import module.decode.p25.reference.VendorLinkControlOpcode;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class LDU1Message extends LDUMessage
 {
     private final static Logger mLog = LoggerFactory.getLogger(LDU1Message.class);
 
-	public static final int ENCRYPTION_FLAG = 352;
+    public static final int ENCRYPTED_LINK_CONTROL_WORD_FLAG = 352;
     public static final int IMPLICIT_VENDOR_FLAG = 353;
     public static final int[] OPCODE = {354, 355, 356, 357, 362, 363};
     public static final int[] VENDOR = {364, 365, 366, 367, 372, 373, 374, 375};
@@ -81,10 +79,14 @@ public class LDU1Message extends LDUMessage
         mCRC = message.mCRC;
     }
 
-	@Override
+    /**
-	public boolean isEncrypted()
+     * Indicates if the contents of the Link Control Word are encrypted.
+     *
+     * @return true if the contents of the LCW are encrypted.
+     */
+    public boolean isEncryptedLinkControlWord()
     {
-		return mMessage.get( ENCRYPTION_FLAG );
+        return mMessage.get(ENCRYPTED_LINK_CONTROL_WORD_FLAG);
     }
 
     private void checkCRC()
@@ -197,7 +199,7 @@ public class LDU1Message extends LDUMessage
 
         sb.append(super.getMessageStub());
 
-		if( isEncrypted() )
+        if(isEncryptedLinkControlWord())
         {
             sb.append("ENCRYPTED");
         }

src/module/decode/p25/message/ldu/LDU2Message.java

@@ -73,8 +73,10 @@ public class LDU2Message extends LDUMessage
 	    checkCRC();
     }
 
-	@Override
+	/**
-	public boolean isEncrypted()
+	 * Indicates if the audio stream is encrypted
+	 */
+	public boolean isEncryptedAudio()
 	{
 		Encryption encryption = getEncryption();
 		

src/module/decode/p25/message/ldu/LDUMessage.java

@@ -35,8 +35,6 @@ public abstract class LDUMessage extends P25Message
 	    super( message, duid, aliasList );
     }
 	
-	public abstract boolean isEncrypted();
-	
 	@Override
     public String getMessage()
     {