[plc4x] 01/02: - PLC4X-207 - No registered handler found for message TPKTPacket[], , using default decode method - Communication with S7 and Modbus device hangs

[cd...@apache.org]

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cdutz pushed a commit to branch feature/plc4c
in repository https://gitbox.apache.org/repos/asf/plc4x.git

commit 8d1afb3ed2418e30e165d1e258f49348ef63d775
Author: Christofer Dutz <ch...@c-ware.de>
AuthorDate: Wed Sep 16 13:42:13 2020 +0200

    - PLC4X-207 - No registered handler found for message TPKTPacket[], , using default decode method - Communication with S7 and Modbus device hangs
    
    Duplicated the Modbus fix for overflowing PDUs from the Modbus to the S7 protocol.
---
 .../apache/plc4x/java/s7/readwrite/protocol/S7ProtocolLogic.java | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/plc4j/drivers/s7/src/main/java/org/apache/plc4x/java/s7/readwrite/protocol/S7ProtocolLogic.java b/plc4j/drivers/s7/src/main/java/org/apache/plc4x/java/s7/readwrite/protocol/S7ProtocolLogic.java
index 0b6e4ec..133cffc 100644
--- a/plc4j/drivers/s7/src/main/java/org/apache/plc4x/java/s7/readwrite/protocol/S7ProtocolLogic.java
+++ b/plc4j/drivers/s7/src/main/java/org/apache/plc4x/java/s7/readwrite/protocol/S7ProtocolLogic.java
@@ -206,6 +206,10 @@ public class S7ProtocolLogic extends Plc4xProtocolBase<TPKTPacket> {
     private CompletableFuture<S7Message> readInternal(S7MessageRequest request) {
         CompletableFuture<S7Message> future = new CompletableFuture<>();
         int tpduId = tpduGenerator.getAndIncrement();
+        // If we've reached the max value for a 16 bit transaction identifier, reset back to 1
+        if(tpduGenerator.get() == 0xFFFF) {
+            tpduGenerator.set(1);
+        }
 
         // Create a new Request with correct tpuId (is not known before)
         S7MessageRequest s7MessageRequest = new S7MessageRequest(tpduId, request.getParameter(), request.getPayload());
@@ -243,6 +247,11 @@ public class S7ProtocolLogic extends Plc4xProtocolBase<TPKTPacket> {
             payloadItems.add(serializePlcValue(field, plcValue));
         }
         final int tpduId = tpduGenerator.getAndIncrement();
+        // If we've reached the max value for a 16 bit transaction identifier, reset back to 1
+        if(tpduGenerator.get() == 0xFFFF) {
+            tpduGenerator.set(1);
+        }
+
         TPKTPacket tpktPacket = new TPKTPacket(new COTPPacketData(null,
             new S7MessageRequest(tpduId,
                 new S7ParameterWriteVarRequest(parameterItems.toArray(new S7VarRequestParameterItem[0])),