added to the udp server code

request is received well, no reply seen in the Qt application, could be because i had to correct code to this version of Qt creator.

Waiting on validation of correct changes from Wim Dams

project/Core/Src/UDP_broadcast.c

@@ -8,6 +8,7 @@
 #include "UDP_broadcast.h"
 
 static const char *TAG = "UDP_broadcast";
+static char reply_str[100] = "|no reply formatted yet|";
 
 /**
  * @fn void owner_details_error_handler(owner_details_t*, char*, char*)
@@ -109,6 +110,7 @@ static uint8_t set_owner_details_reply(owner_details_t *owner, char *reply){
 	if(reply != NULL && owner != NULL){
 		LOG_DEBUG(TAG,"set: %s",reply);
 		strncpy(owner->reply,reply,sizeof(owner->reply));
+		strncpy(reply_str,reply,sizeof(reply_str));
 		return 1;
 	}
 	else{
@@ -238,12 +240,21 @@ char* get_owner_details_reply(owner_details_t *owner){
  * @param port
  */
 
-static void udp_receive_callback(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port){
+#define MAX_DATA_SIZE 50  // Define the maximum expected data size
+#define UDP_QUESTION1 "Where are you?v1.0"
+
+static void udp_receive_callback(void *arg, struct udp_pcb *connection, struct pbuf *p, const ip_addr_t *addr, u16_t port){
 	int i;
 	int len;
 	char *pc;
-	char data[1024];
+	char data[MAX_DATA_SIZE];
 	char source_ip_str[16];
+	struct pbuf *p_data;
+
+	memset(data, 0, sizeof(data));
+
+
+
 
 	// Convert the source IP address to a string for printing.
 	ipaddr_ntoa_r(addr, source_ip_str, sizeof(source_ip_str));
@@ -251,14 +262,34 @@ static void udp_receive_callback(void *arg, struct udp_pcb *upcb, struct pbuf *p
 	if (p != NULL) {
 		pc = (char*)p->payload;
 		len = p->tot_len;
-
+		p_data = pbuf_alloc(PBUF_TRANSPORT, sizeof(reply_str), PBUF_RAM);
-		for(i = 0; i < len; i++) {
+		if (p_data == NULL){
-			data[i] = pc[i];
+			LOG_WARN(TAG,"udp_receive_callback: unable to allocated data buffer for reply");
+		}
+		else if(len <= MAX_DATA_SIZE){
+			for(i = 0; i < len; i++) {
+				data[i] = pc[i];
+			}
+
+			LOG_INFO(TAG,"udp_receive_callback: received data from %s at port: %d: %s",source_ip_str,port,data);
+			if(strcmp(data,UDP_QUESTION1) == 0){
+				*((uint32_t*)p_data->payload) = reply_str;
+				p_data->len = sizeof(reply_str);
+				p_data->tot_len = sizeof(reply_str);
+				udp_sendto(connection, p_data, addr, port);
+				LOG_INFO(TAG,"tried to reply to %s at port: %d: %s",source_ip_str,port,reply_str);
+			}
+
+		}
+		else{
+			LOG_WARN(TAG,"udp_receive_callback: input buffer was bigger than max size %d",MAX_DATA_SIZE);
 		}
-		pbuf_free(p);
 
-		LOG_DEBUG(TAG,"received data from %s at port: %d: %s",source_ip_str,port,data);
 	}
+	else{
+		LOG_WARN(TAG,"udp_receive_callback: input buffer was a NULL pointer");
+	}
+	pbuf_free(p);
 }
 
 /**
@@ -276,7 +307,7 @@ err_t init_UDP_server(){
 	if(connection != NULL){
 		err = udp_bind(connection, IP_ANY_TYPE, 64000);
 	    if(err == ERR_OK){
-		    udp_recv(connection, udp_receive_callback, NULL);
+		    udp_recv(connection, udp_receive_callback,NULL);
 		    LOG_INFO(TAG,"initialising UDP server succesfull, callback running");
 		}
 		else{

project/Core/Src/main.c

@@ -111,8 +111,8 @@ int main(void)
   MX_LWIP_Init();
   MX_QUADSPI_Init();
   /* USER CODE BEGIN 2 */
-    init_UDP_server();
     owner_details_t owner;
+    init_UDP_server();
 
   	if(!set_owner_details(&owner, "joran", "vn")){
   		LOG_DEBUG(TAG,"error");;