Simple UDP client in C using winsock2

udp_listener.c

// UDPListener.cpp : Defines the entry point for the console application.

#include "stdafx.h"
#include <stdio.h>
#include <string.h>
#include <windows.h>      // Needed for all Winsock stuff

#pragma comment(lib,"ws2_32.lib") //Winsock Library

#define  PORT_NUM           5001  // Port number used
#define  IP_ADDR      "127.0.0.1" // IP address of server1 (*** HARDWIRED ***)
#define  NET_BUFF_SIZE      400

void NET_recv(int client, sockaddr_in server_addr, char *buffer)
{
    char data_out[NET_BUFF_SIZE];
    int addr_len = sizeof(server_addr);

    int retcode = recvfrom(client, data_out, NET_BUFF_SIZE, 0, (struct sockaddr *)&server_addr, &addr_len);
    if (retcode < 0)
    {
        int err = WSAGetLastError();
        printf("recvfrom() failed with error code : %d\n", err);
        return;
    }
    data_out[ retcode ] = 0;
    memcpy(buffer, data_out, retcode + 1);
}

int setup_socket(int *client_s, sockaddr_in *server_addr, int port_num)
{
    WORD wVersionRequested = MAKEWORD(1, 1);       // Stuff for WSA functions
    WSADATA wsaData;                              // Stuff for WSA functions
    int opt = 1;

    WSAStartup(wVersionRequested, &wsaData);

    server_addr->sin_family = AF_INET;                 // Address family to use
    server_addr->sin_port = htons(port_num);           // Port num to use
    server_addr->sin_addr.S_un.S_addr = inet_addr(IP_ADDR);

    *client_s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (client_s < 0)
    {
        printf("*** ERROR - socket() failed \n");
    }

    //UDP Broadcast permissions
    if (setsockopt(*client_s, SOL_SOCKET, SO_BROADCAST, (char *)&opt, sizeof(opt)) == SOCKET_ERROR)
    {
        printf("\nERROR in broadcasting ERROR CODE : %d \n", WSAGetLastError());
        closesocket(*client_s);
        WSACleanup();
        return 1;
    }

    //UDP SOCKET Binding
    if (bind(*client_s, (sockaddr *)server_addr, sizeof(sockaddr_in)) == SOCKET_ERROR)
    {
        int err = WSAGetLastError();
        printf("\nUDP socket binding failed ERROR CODE : %d\n", err);
        closesocket(*client_s);
        WSACleanup();
        return 1;
    }
}

int _tmain(int argc, _TCHAR* argv[])
{
    int client_s;
    sockaddr_in server_addr;
    char buffer[ NET_BUFF_SIZE ];

    printf("Setting up...\n");
    setup_socket(&client_s, &server_addr, PORT_NUM);

    while (true) {
        NET_recv(client_s, server_addr, buffer);
        printf("%s\n", buffer);
    }
    return 0;
}