1 files changed, 15 insertions, 25 deletions

diff --git a/src/org/traccar/protocol/NavisFrameDecoder.java b/src/org/traccar/protocol/NavisFrameDecoder.java
index 0146243cd..8a0bb0b9a 100644
--- a/src/org/traccar/protocol/NavisFrameDecoder.java
+++ b/src/org/traccar/protocol/NavisFrameDecoder.java
@@ -18,39 +18,31 @@ package org.traccar.protocol;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandlerContext;
-import io.netty.handler.codec.TooLongFrameException;
 import java.nio.charset.StandardCharsets;
 import org.traccar.BaseFrameDecoder;
 import org.traccar.BasePipelineFactory;
 
 public class NavisFrameDecoder extends BaseFrameDecoder {
 
-    private int flexDataSize; // bytes
-
     private static final int NTCB_HEADER_LENGTH = 16;
     private static final int NTCB_LENGTH_OFFSET = 12;
     private static final int FLEX_HEADER_LENGTH = 2;
-    private static final int MAX_FRAME_LENGTH = 65551;
+
+    private int flexDataSize;
+
+    public void setFlexDataSize(int flexDataSize) {
+        this.flexDataSize = flexDataSize;
+    }
 
     @Override
     protected Object decode(
             ChannelHandlerContext ctx, Channel channel, ByteBuf buf) throws Exception {
 
-        // Check minimum length
-        if (buf.readableBytes() < 1) {
-            return null;
-        }
-
-        if (buf.readableBytes() > MAX_FRAME_LENGTH) {
-            throw new TooLongFrameException();
-        }
-
         if (buf.getByte(buf.readerIndex()) == 0x7F) {
-            // FLEX keep alive frame
-            return buf.readRetainedSlice(1);
+            return buf.readRetainedSlice(1); // keep alive
         }
 
-        if (ctx != null) {
+        if (ctx != null && flexDataSize == 0) {
             NavisProtocolDecoder protocolDecoder =
                     BasePipelineFactory.getHandler(ctx.pipeline(), NavisProtocolDecoder.class);
             if (protocolDecoder != null) {
@@ -59,7 +51,7 @@ public class NavisFrameDecoder extends BaseFrameDecoder {
         }
 
         if (flexDataSize > 0) {
-            // FLEX frame
+
             if (buf.readableBytes() > FLEX_HEADER_LENGTH) {
                 int length = 0;
                 String type = buf.toString(buf.readerIndex(), 2, StandardCharsets.US_ASCII);
@@ -97,23 +89,21 @@ public class NavisFrameDecoder extends BaseFrameDecoder {
                     return buf.readRetainedSlice(buf.readableBytes());
                 }
             }
+
         } else {
-            // NTCB frame
+
             if (buf.readableBytes() < NTCB_HEADER_LENGTH) {
                 return null;
             }
 
-            int length = buf.getUnsignedShortLE(buf.readerIndex() + NTCB_LENGTH_OFFSET);
-            if (buf.readableBytes() >= NTCB_HEADER_LENGTH + length) {
-                return buf.readRetainedSlice(NTCB_HEADER_LENGTH + length);
+            int length = NTCB_HEADER_LENGTH + buf.getUnsignedShortLE(buf.readerIndex() + NTCB_LENGTH_OFFSET);
+            if (buf.readableBytes() >= length) {
+                return buf.readRetainedSlice(length);
             }
+
         }
 
         return null;
     }
 
-    public void setFlexDataSize(int flexDataSize) {
-        this.flexDataSize = flexDataSize;
-    }
-
 }