fixed: ignore faulty requests

Changelog

@@ -1,3 +1,6 @@
+2024-02-22:
+- fixed: ignore incorrect requests
+
 2023-09-19:
 - performance issues fixed.
 - gui issues if more than 200 values where added fixed.

gui.cc

@@ -343,6 +343,7 @@ gboolean cb_thread_network_data_add (gpointer data) {
 		GtkTextTag *tag_data;
 		GtkTextTag *tag_info;
 		GtkTextTag *tag_modbus;
+		GtkTextTag *tag_error;
 		time_t _tm =time(NULL);
 		struct tm * curtime = localtime (&_tm);
 		static int _once = 0;
@@ -355,6 +356,8 @@ gboolean cb_thread_network_data_add (gpointer data) {
 						"foreground", "black", "style", PANGO_WEIGHT_NORMAL, "family", "Monospace", NULL);
 			tag_info = gtk_text_buffer_create_tag (textbuffer, "Info",
 						"foreground", "green", "style", PANGO_WEIGHT_THIN, "family", "Sans", NULL);
+			tag_error = gtk_text_buffer_create_tag (textbuffer, "Error",
+						"foreground", "red", "style", PANGO_WEIGHT_BOLD, "family", "Sans", NULL);
 			tag_modbus = gtk_text_buffer_create_tag (textbuffer, "Modbus",
 						"foreground", "black", "style", PANGO_WEIGHT_NORMAL, "family", "Sans", NULL);
 		}
@@ -372,11 +375,12 @@ gboolean cb_thread_network_data_add (gpointer data) {
 			else if (i % 32 == 0) text += "\n        ";
 			else if (i % 4  == 0 && i > 0) text += " : ";
 			else if (i % 2  == 0 && i > 0) text += ":";
-//			else text += " ";
 
 			text += hexnum[c/16];
 			text += hexnum[c%16];
 		}
+		text += "\n";
+
 		gtk_text_buffer_get_start_iter(textbuffer, &start);
 		gtk_text_buffer_insert_with_tags_by_name(textbuffer, &start, text.c_str(), -1, "Data", NULL);
 
@@ -407,20 +411,30 @@ gboolean cb_thread_network_data_add (gpointer data) {
 				text = text + " Cnt: " + std::to_string (mbdata->regcnt);
 			}
 		}
-		text = text + "\n";
+		text = text + " Bytecnt: "+ std::to_string (mbdata->bytecnt) +"\n";
 		gtk_text_buffer_get_start_iter(textbuffer, &start);
 		gtk_text_buffer_insert_with_tags_by_name(textbuffer, &start, text.c_str(), -1, "Modbus", NULL);
 
 		//
+		// number of bytes
+		text = std::to_string(mbdata->bufferlen) + " Bytes";
+		gtk_text_buffer_get_start_iter(textbuffer, &start);
+		gtk_text_buffer_insert_with_tags_by_name(textbuffer, &start, text.c_str(), -1, "Info", NULL);
+
 		//
-		text ="";
-		text += mbdata->hostname;
-		if (mbdata->direction == 0) text = text + " RECV ";
-		else 						text = text + " SEND ";
-		text = text + std::to_string(mbdata->bufferlen) + " Bytes";
+		// Hostname
+		text = mbdata->hostname;
 		gtk_text_buffer_get_start_iter(textbuffer, &start);
 		gtk_text_buffer_insert_with_tags_by_name(textbuffer, &start, text.c_str(), -1, "Info", NULL);
 
+		//
+		// direction or error
+		if 		(mbdata->direction == 0)
+			gtk_text_buffer_insert_with_tags_by_name(textbuffer, &start, (const char*)" RECV ", -1, "Info", NULL);
+		else if	(mbdata->direction == 1)
+			gtk_text_buffer_insert_with_tags_by_name(textbuffer, &start, (const char*)" SEND ", -1, "Info", NULL);
+		else
+			gtk_text_buffer_insert_with_tags_by_name(textbuffer, &start, (const char*)" ** ERROR **", -1, "Error", NULL);
 
 		//
 		// add date

modbussrv.cc

@@ -123,24 +123,6 @@ void ModbusSrv::SetCallback (gboolean (*callback_func)(gpointer data)) {
 	onchangecallback = callback_func;
 }
 
-/***************************************************************************************************
- * this should only be called from within the ServerThread function
- */
-void ModbusSrv::ReadData(gpointer pdata) {
-	int slot;
-	long int len;
-
-	for (slot = 0; slot < MODBUS_MAXCLIENTS; slot++) if (&clients[slot] == pdata) break;
-
-	if (slot < 0 || slot >= MODBUS_MAXCLIENTS) return;	// slot out of bound
-	if (clients[slot] == NULL) return; 					// slot not connected?
-
-	len = clients[slot]->Read(inbuffer, MODBUS_IOBUFFER);
-	if (len < 0) {
-		CloseConnection(slot);
-	}
-};
-
 
 void ModbusSrv::ServerThread() {
 	int keep_running = 1;
@@ -232,9 +214,12 @@ void ModbusSrv::ServerThread() {
 					mbindata->transactionid = 0;
 					mbindata->protoolid = 0;
 
-					Decode(mbindata);
+					if (Decode(mbindata) == 0) {
+						mbindata->direction = 2;	// mark as error
+						gdk_threads_add_idle(cb_thread_network_data_add, mbindata);
+						continue;
+					}
 					gdk_threads_add_idle(cb_thread_network_data_add, mbindata);
-
 					//
 					// fill in outdata
 					//
@@ -677,12 +662,14 @@ int ModbusSrv::WorkerAndEncodeWriteMulti(struct modbus_data *mbin, struct modbus
 }
 
 
-
-void ModbusSrv::Decode(struct modbus_data *mbdata) {
+//
+// return 1 on success, 0 on error
+int ModbusSrv::Decode(struct modbus_data *mbdata) {
 	//
 	uint16_t i16;
 	uint8_t	 i8;
 	int pos = 0;
+	int ret = 1;
 
 	mbdata->fc = 0;
 	mbdata->regcnt = -1;
@@ -694,7 +681,7 @@ void ModbusSrv::Decode(struct modbus_data *mbdata) {
 	mbdata->protoolid = 0;
 	mbdata->bytecnt = 0;
 
-	if (mbdata->bufferlen < 8) return;
+	if (mbdata->bufferlen < 8) return 0;
 
 	// Transaction
 	memcpy (&i16, mbdata->buffer+pos, sizeof(i16));
@@ -712,29 +699,36 @@ void ModbusSrv::Decode(struct modbus_data *mbdata) {
 	mbdata->length = ntohs(i16);
 
 	// unitid
+	if (mbdata->length < pos-6) ret = 0;
 	memcpy (&i8, mbdata->buffer+pos, sizeof(i8));
 	pos += sizeof(i8);
 	mbdata->unitid = i8;
 
 	// function code
+	if (mbdata->length < pos-6) ret = 0;
 	memcpy (&i8, mbdata->buffer+pos, sizeof(i8));
 	pos += sizeof(i8);
 	mbdata->fc = i8;
 
 	// register
+	if (mbdata->length < pos-6) ret = 0;
 	memcpy (&i16, mbdata->buffer+pos, sizeof(i16));
 	pos += sizeof(i16);
 	mbdata->regstart = ntohs(i16);
 
 	// number of registers
+	if (mbdata->length < pos-6) ret = 0;
 	memcpy (&i16, mbdata->buffer+pos, sizeof(i16));
 	pos += sizeof(i16);
 	mbdata->regcnt = ntohs(i16);
 
-	// unitid
+	// bytecnt
+	// if (mbdata->length < pos-6) ret = 0;
 	memcpy (&i8, mbdata->buffer+pos, sizeof(i8));
 	pos += sizeof(i8);
 	mbdata->bytecnt = i8;
+
+	return ret;
 };
 
 int ModbusSrv::GetRegister(int fc, int regnum, ModbusRegister *r) {

modbussrv.h

@@ -36,7 +36,7 @@ struct modbus_data {
 	int protoolid;
 	int length;
 	int unitid;
-	int direction;
+	int direction;		// 0 - RECV, 1 - SEND, 2 - ERROR
 	int fc;
 	int regstart;
 	int regcnt;
@@ -77,8 +77,8 @@ private:
 	char inbuffer[MODBUS_IOBUFFER];
 	char outbuffer[MODBUS_IOBUFFER];
 
-	void Decode(struct modbus_data *mbdata);
-	// return 0 on error, 1 on no error
+	int Decode(struct modbus_data *mbdata);
+	// return 0 on error, 1 on success
 	int WorkerAndEncodeRead(struct modbus_data *mbin, struct modbus_data *mbout);
 	int WorkerAndEncodeWriteSingle(struct modbus_data *mbin, struct modbus_data *mbout);
 	int WorkerAndEncodeWriteMulti(struct modbus_data *mbin, struct modbus_data *mbout);
@@ -97,7 +97,7 @@ public:
 	int SetRegister(int fc, int regnum, ModbusRegister *r);
 	int SetRegisters(int fc, int regnum, int count, ModbusRegister *r);
 	void CloseConnection(int slot);
-	void ReadData(gpointer pdata);
+	// void ReadData(gpointer pdata);
 
 	void Enable(int fc, int regstart, int count, int onoff);
 	void EnableAll(int onoff);