Ignore requests with unknown Unit ID (#27)

wirenboard · May 30, 2023 · 1eecb52 · 1eecb52
1 parent 7cd2d71
commit 1eecb52
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diff --git a/debian/changelog b/debian/changelog
@@ -1,3 +1,9 @@
+wb-mqtt-mbgate (1.5.5) stable; urgency=medium
+
+  * Ignore requests with unknown Unit ID
+
+ -- Nikolay Korotkiy <nikolay.korotkiy@wirenboard.com>  Mon, 29 May 2023 17:30:00 +0400
+
 wb-mqtt-mbgate (1.5.4) stable; urgency=medium
 
   * Enable debug logging from libmodbus

diff --git a/src/modbus_wrapper.cpp b/src/modbus_wrapper.cpp
@@ -64,6 +64,11 @@ void TModbusServer::Observe(PModbusServerObserver o,
 #undef PROCESS
 }
 
+bool TModbusServer::IsObserved(uint8_t slave_id) const
+{
+    return _maxSlaveAddresses.find(slave_id) != _maxSlaveAddresses.end();
+}
+
 static void _callCacheAllocate(const TModbusAddressRange& range, uint8_t slave_id, TStoreType store, void* cache_start)
 {
     map<PModbusServerObserver, TModbusCacheAddressRange> observers;
@@ -121,8 +126,10 @@ int TModbusServer::Loop(int timeoutMilliS)
     // receive message, process, run callback
     while (mb->Available()) {
         TModbusQuery q = mb->ReceiveQuery();
-        if (q.size > 0)
+        auto slave_id = q.data[q.header_length - 1];
+        if (q.size > 0 && IsObserved(slave_id)) {
             _ProcessQuery(q);
+        }
     }
 
     return 0;

diff --git a/src/modbus_wrapper.h b/src/modbus_wrapper.h
@@ -328,6 +328,12 @@ class TModbusServer
                          uint8_t slave_id = 0);
     /* virtual void Unobserve(PModbusServerObserver o) = 0; */
 
+    /*! Check if slave ID is observed
+     * \param slave Slave ID
+     * \return true if slave ID is observed
+     */
+    virtual bool IsObserved(uint8_t slave_id) const;
+
 private:
     void _ProcessQuery(const TModbusQuery& query);
     void _ProcessReadQuery(TStoreType type,