Error in assigning port number to socket using newSocket.sin_port = htons(portNumber);

Question

I am trying to assign port number passed to it by a function. The port number received is displayed correctly when received but when I try to assign that port number to a new Socket, that port number is not assigned and some other number 52428 is assigned everytime. I tried my best to figure out the error myself but I failed :( Please help me. Below is my code:

DWORD WINAPI newrecvThreadProcedure(LPVOID param)
{       
   newRecvThreadDetailStruct* myDetailStruct =  (newRecvThreadDetailStruct*) (param);
   char ipNumber[12], newDetail[256], threadNumber_char[12], 
        *detail =    myDetailStruct>newsocketDetail;
   int portNumber, threadNumber_int = myDetailStruct->threadNum; 
   sscanf(detail,"%s %d",ipNumber,&portNumber);
   char displayPortNum[12];
   itoa(portNumber,displayPortNum,10);
   MessageBox( NULL, displayPortNum,"portnumber", MB_ICONINFORMATION); //Port Number displayed here is the value that I want i.e. 8880 
// =======================================================================================
// Creating New Socket Now
   WSADATA wsa; 

   //Initialise winsock
   if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
      {
    //"WinSock Initialization FAILED"
        return 0;
      }

   //Create a socket
   SOCKET newSocketIdentifier;
   SOCKADDR_IN newSocket;
   if((newSocketIdentifier = socket(AF_INET , SOCK_DGRAM , 0 )) == INVALID_SOCKET)
      {
        //"Socket Creation Failed",
         exit(EXIT_FAILURE);
      }
   //Socket Created

   //Prepare the sockaddr_in structure
   newSocket.sin_family = AF_INET;
   newSocket.sin_addr.s_addr = INADDR_ANY;
   newSocket.sin_port = htons(portNumber);
   char char_port[12],*client_ip = inet_ntoa(newSocket.sin_addr); 
   int int_port = ntohs(newSocket.sin_port);
   itoa(int_port,char_port,10);
   MessageBox( NULL,char_port,client_ip,MB_ICONEXCLAMATION | MB_OK);  /* Port number 
displayed here is 52428 and IP Address is 0.0.0.0*/
}

Answer 1

The string buffer ipNumber is too small. It's only 12 characters, but a full IP might be "255.255.255.255" which is 16 characters (including the terminator).

So you might have a buffer overrun, leading to undefined behavior.

You should use a debugger to look in the various fields of the structs, to see that all is well.