Memory leak, examples and API fixes

- Fix memory leak (issue #208)
- Extend cbEnable/cbDisable API
- Fix TCP-to-RTU example

Author: emelianov

CMakeLists.txt

@@ -0,0 +1,6 @@
+set(COMPONENT_ADD_INCLUDEDIRS src)
+set(COMPONENT_SRCS "src/Modbus.cpp" "src/ModbusRTU.cpp")
+set(COMPONENT_PRIV_REQUIRES arduino)
+register_component()
+
+

examples/Bridge/README.md

@@ -42,21 +42,22 @@ struct frame_arg_t {
 		uint8_t slaveId;
         // For ModbusTCP/TLS
 		struct { 
-			uint8_t unitId; // UnitId as passed in Modbus header
+			uint8_t unitId; // UnitId as passed in MBAP header
 			uint32_t ipaddr; // IP address from which frame is received
-			uint16_t transactionId; // TransactionId as passed im Modbus header
+			uint16_t transactionId; // TransactionId as passed in MBAP header
 		};
     };
 };
 typedef std::function<ResultCode(uint8_t*, uint8_t, void*)> cbRaw; // Callback function Type for STL
 typedef ResultCode (*cbRaw)(uint8_t* frame, uint8 len, void* data); // Callback function Type
 bool onRaw(cbRaw cb = nullptr);
 ```
-- `frame` Modbus payload frame with stripped MBAP, slaveid and crc
+- `frame` Modbus payload frame with stripped MBAP/slaveid and crc
 - `len` frame size in bytes
 - `data` Pointer to frame_arg_t filled with frame header information
+
 *Returns:*
-- If a special error code `Modbus::EX_PASSTHROU` returned frame will be processed normally
+- If a special error code `Modbus::EX_PASSTHROUGH` returned frame will be processed normally
 - If a special error code `Modbus::EX_FORCE_PROCESS` returned frame will be processed even if addressed to another Modbus unit
 - Any other return code disables normal frame processing. Only transactional callback will be executed (if any and transaction data is correct)
 The callback is executed only on Modbus frame with valid header and CRC.

examples/Bridge/TCP-to-RTU-Simulator/TCP-to-RTU-Simulator.ino

@@ -58,24 +58,24 @@ Modbus::ResultCode cbTcpRaw(uint8_t* data, uint8_t len, void* custom) {
 
   if (transRunning) { // Note that we can't process new requests from TCP-side while waiting for responce from RTU-side.
     tcp.setTransactionId(transRunning); // Set transaction id as per incoming request
-    tcp.errorResponce(src->ipaddr, (Modbus::FunctionCode)data[0], Modbus::EX_SLAVE_DEVICE_BUSY);
+    tcp.errorResponce(IPAddress((src->ipaddr), (Modbus::FunctionCode)data[0], Modbus::EX_SLAVE_DEVICE_BUSY);
     return Modbus::EX_SLAVE_DEVICE_BUSY;
   }
 
-  rtu.rawRequest(slaveRunning, data, len, cbRtuTrans);
+  rtu.rawRequest(src->unitId, data, len, cbRtuTrans);
 
   if (src->unitId) {
     tcp.setTransactionId(transRunning); // Set transaction id as per incoming request
 
     //uint16_t succeed = tcp.rawResponce(src->ipaddr, data, len, slaveRunning);
 
-    tcp.errorResponce(src->ipaddr, (Modbus::FunctionCode)data[0], Modbus::EX_ACKNOWLEDGE);
+    tcp.errorResponce(IPAddress(src->ipaddr), (Modbus::FunctionCode)data[0], Modbus::EX_ACKNOWLEDGE);
     return Modbus::EX_ACKNOWLEDGE;
   }
 
-  srcIp = src->ipaddr;
+  srcIp = IPAddress(src->ipaddr);
 
-  slaveRunning = src->slaveId;
+  slaveRunning = src->unitId;
 
   transRunning = src->transactionId;
 

src/Modbus.cpp

@@ -824,11 +824,13 @@ void Modbus::masterPDU(uint8_t* frame, uint8_t* sourceFrame, TAddress startreg,
     }
 }
 
-void Modbus::cbEnable(bool state) {
+bool Modbus::cbEnable(const bool state) {
+    const bool old_state = state;
     cbEnabled = state;
+    return old_state;
 }
-void Modbus::cbDisable() {
-    cbEnable(false);
+bool Modbus::cbDisable() {
+    return cbEnable(false);
 }
 Modbus::~Modbus() {
     free(_frame);

src/Modbus.h

@@ -193,8 +193,8 @@ class Modbus {
 
         ~Modbus();
 
-        void cbEnable(bool state = true);
-        void cbDisable();
+        bool cbEnable(const bool state = true);
+        bool cbDisable();
 
     private:
 	    ResultCode readBits(TAddress startreg, uint16_t numregs, FunctionCode fn);

src/ModbusTCPTemplate.h

@@ -219,8 +219,10 @@ void ModbusTCPTemplate<SERVER, CLIENT>::task() {
 			Serial.println("IP: Accepted");
 #endif
 			CLIENT* currentClient = new CLIENT(c);
-			if (!currentClient || !currentClient->connected())
+			if (!currentClient || !currentClient->connected()) {
+				delete currentClient;
 				continue;
+			}
 #if defined(MODBUSRTU_DEBUG)
 			Serial.println("IP: Connected");
 #endif
@@ -544,7 +546,7 @@ bool ModbusTCPTemplate<SERVER, CLIENT>::disconnect(IPAddress ip) {
 		return false;
 	int8_t p = getSlave(ip);
 	if (p != -1) {
-		tcpclient[p]->stop();
+		//tcpclient[p]->stop();
 		delete tcpclient[p];
 		tcpclient[p] = nullptr;
 		return true;
@@ -565,6 +567,7 @@ void ModbusTCPTemplate<SERVER, CLIENT>::dropTransactions() {
 template <class SERVER, class CLIENT>
 ModbusTCPTemplate<SERVER, CLIENT>::~ModbusTCPTemplate() {
 	free(_frame);
+	_frame = nullptr;
 	dropTransactions();
 	cleanupConnections();
 	cleanupTransactions();