/*  UDP ServerSide Console App */
/*  Bill Tompkins 4/2012       */
/*  Use code at your own risk  */

#include "stdafx.h"
#include <stdio.h>
#include <string.h>
#include <winsock2.h>
//#include <iostream.h>

#pragma comment(lib,"ws2_32.lib") //Windows Socket Library
 
#define BUFLEN 512  //Max length of buffer
#define PORT 8887   //The port on which to listen for incoming data
 
int main()
{
    SOCKET s;
    struct sockaddr_in server, si_other;
    int slen , recv_len;
    char buf[BUFLEN];
    WSADATA wsa;
 
    slen = sizeof(si_other) ;
     
    //Initialize winsock
	printf("\nUDP Text Demo (ServerSide)");
    printf("\nInitializing Winsock...");
    if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
    {
        printf("Failed. Error Code : %d",WSAGetLastError());
        exit(EXIT_FAILURE);
    }
    printf("\nInitialized.\n");
     
    //Create a socket
    if((s = socket(AF_INET , SOCK_DGRAM , 0 )) == INVALID_SOCKET)
    {
        printf("Socket Routine Failed.  Error Code: %d" , WSAGetLastError());
    }
    printf("\nSocket created.\n");
     
    //Prepare the sockaddr_in structure
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY;
    server.sin_port = htons( PORT );
     
    //Bind
    if( bind(s ,(struct sockaddr *)&server , sizeof(server)) == SOCKET_ERROR)
    {
        printf("\nBind Failed.  Error Code: %d" , WSAGetLastError());
        exit(EXIT_FAILURE);
    }
    puts("\nBind Successful");
 
    //keep listening for data
    while(1)
    {
        printf("\nWaiting for Data...");
        fflush(stdout);
         
        //clear the buffer by filling null, it might have previously received data
        memset(buf,'\0', BUFLEN);
         
        //try to receive some data, this is a blocking call
        if ((recv_len = recvfrom(s, buf, BUFLEN, 0, (struct sockaddr *) &si_other, &slen)) == SOCKET_ERROR)
        {
	    printf("Recvfrom Routine Failed.  Error Code: %d" , WSAGetLastError());
            exit(EXIT_FAILURE);
        }
         
        //print details of the client/peer and the data received
		printf("\n");
        printf("Received Packet from %s:%d\n", inet_ntoa(si_other.sin_addr), ntohs(si_other.sin_port));
        printf("Data: %s\n" , buf);
		printf("Length: %d\n" , strlen(buf));
         
        //now reply the client with the same data
        if (sendto(s, buf, recv_len, 0, (struct sockaddr*) &si_other, slen) == SOCKET_ERROR)
        {
            printf("Sendto Routine Failed.  Error Code: %d" , WSAGetLastError());
            exit(EXIT_FAILURE);
        }
    }
 
    closesocket(s);
    WSACleanup();
     
    return 0;
}