From 1c420b8eeee4844781c18048b51f80e665148f94 Mon Sep 17 00:00:00 2001
From: Denny Sheirer <dennissheirer2002@yahoo.com>
Date: Fri, 19 Jan 2024 10:23:27 -0500
Subject: [PATCH] #1787 Resolves issue with channel rotation and rest channel
 reallocation for Capacity Plus systems. (#1798)

Co-authored-by: sheirerd <sheirerd@ainfosec.com>
---
 .../module/decode/dmr/DMRDecoderState.java    |  3 +-
 .../decode/dmr/DMRMessageProcessor.java       | 12 +++++--
 .../decode/dmr/DMRTrafficChannelManager.java  | 32 +++++++++++++++++--
 3 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/src/main/java/io/github/dsheirer/module/decode/dmr/DMRDecoderState.java b/src/main/java/io/github/dsheirer/module/decode/dmr/DMRDecoderState.java
index f83f5960c..88e09f5eb 100644
--- a/src/main/java/io/github/dsheirer/module/decode/dmr/DMRDecoderState.java
+++ b/src/main/java/io/github/dsheirer/module/decode/dmr/DMRDecoderState.java
@@ -1361,10 +1361,11 @@ public void receiveDecoderStateEvent(DecoderStateEvent event)
                 }
                 break;
             case NOTIFICATION_SOURCE_FREQUENCY:
+                long previous = mCurrentFrequency;
                 mCurrentFrequency = event.getFrequency();
                 if(hasTrafficChannelManager())
                 {
-                    mTrafficChannelManager.setCurrentControlFrequency(mCurrentFrequency, mChannel);
+                    mTrafficChannelManager.setCurrentControlFrequency(previous, mCurrentFrequency, mChannel);
                 }
                 break;
             default:
diff --git a/src/main/java/io/github/dsheirer/module/decode/dmr/DMRMessageProcessor.java b/src/main/java/io/github/dsheirer/module/decode/dmr/DMRMessageProcessor.java
index ee19b0687..fb29ca5e7 100644
--- a/src/main/java/io/github/dsheirer/module/decode/dmr/DMRMessageProcessor.java
+++ b/src/main/java/io/github/dsheirer/module/decode/dmr/DMRMessageProcessor.java
@@ -25,6 +25,7 @@
 import io.github.dsheirer.module.decode.dmr.identifier.DMRTalkgroup;
 import io.github.dsheirer.module.decode.dmr.message.CACH;
 import io.github.dsheirer.module.decode.dmr.message.DMRBurst;
+import io.github.dsheirer.module.decode.dmr.message.data.DataMessageWithLinkControl;
 import io.github.dsheirer.module.decode.dmr.message.data.IDLEMessage;
 import io.github.dsheirer.module.decode.dmr.message.data.block.DataBlock;
 import io.github.dsheirer.module.decode.dmr.message.data.csbk.CSBKMessage;
@@ -48,12 +49,13 @@
 import io.github.dsheirer.module.decode.dmr.message.voice.VoiceMessage;
 import io.github.dsheirer.module.decode.dmr.message.voice.VoiceSuperFrameProcessor;
 import io.github.dsheirer.sample.Listener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 /**
  * Processes DMR messages and performs re-assembly of link control fragments
@@ -154,6 +156,12 @@ else if(message instanceof DMRBurst dmrBurst && isValid(dmrBurst))
             }
         }
 
+        //Process data messages carrying a link control payload so that the LC payload can be processed/enriched
+        if(message instanceof DataMessageWithLinkControl linkControlCarrier)
+        {
+            receive(linkControlCarrier.getLCMessage());
+        }
+
         //Enrich messages that carry DMR Logical Channel Numbers with LCN to frequency mappings
         if(message instanceof ITimeslotFrequencyReceiver)
         {
diff --git a/src/main/java/io/github/dsheirer/module/decode/dmr/DMRTrafficChannelManager.java b/src/main/java/io/github/dsheirer/module/decode/dmr/DMRTrafficChannelManager.java
index 8467ab01a..35bd45eeb 100644
--- a/src/main/java/io/github/dsheirer/module/decode/dmr/DMRTrafficChannelManager.java
+++ b/src/main/java/io/github/dsheirer/module/decode/dmr/DMRTrafficChannelManager.java
@@ -134,12 +134,38 @@ public DMRTrafficChannelManager(Channel parentChannel)
     /**
      * Sets the current parent control channel frequency so that channel grants for the current frequency do not
      * produce an additional traffic channel allocation.
-     * @param currentControlFrequency for current control channel.
+     * @param previousControlFrequency for the current control channel (to remove from allocated channels)
+     * @param currentControlFrequency for current control channel (to add to allocated channels)
      * @param channel for the current control channel
      */
-    public void setCurrentControlFrequency(long currentControlFrequency, Channel channel)
+    public void setCurrentControlFrequency(long previousControlFrequency, long currentControlFrequency, Channel channel)
     {
-        mAllocatedChannelFrequencyMap.put(currentControlFrequency, channel);
+        if(previousControlFrequency == currentControlFrequency)
+        {
+            return;
+        }
+
+        mLock.lock();
+
+        try
+        {
+            Channel existing = mAllocatedChannelFrequencyMap.get(previousControlFrequency);
+
+            //Only remove the channel if it is non-null and it matches the current control channel.
+            if(channel.equals(existing))
+            {
+                //Unlock the frequency in the channel rotation monitor
+                getInterModuleEventBus().post(FrequencyLockChangeRequest.unlock(previousControlFrequency));
+                mAllocatedChannelFrequencyMap.remove(previousControlFrequency);
+            }
+
+            mAllocatedChannelFrequencyMap.put(currentControlFrequency, channel);
+            getInterModuleEventBus().post(FrequencyLockChangeRequest.lock(currentControlFrequency));
+        }
+        finally
+        {
+            mLock.unlock();
+        }
     }
 
     /**