/*
   udp2.c: illustrate bind() on INADDR_ANY IP-address
	   - result: this will work on any machine without you needing to
	   - know its IP address, and as long as the specified port is
	   - avaliable (not used by a diff. process)
*/

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

void main(int argc, char *argv[])
{
   int s;				/* s = socket */
   struct sockaddr_in in_addr;		/* Internet address */

   if (argc < 2)
    { printf("Usage: %s <port>\n", argv[0]);
      printf("    Program creates a UDP socket and binds it to <port>\n",
		  argv[0]);
      exit(1);
    }

   /* ---
      Create a socket
      --- */
   s = socket(PF_INET, SOCK_DGRAM, 0);

   /* ---
      Set up socket end-point info for binding
      --- */
   in_addr.sin_family = AF_INET;                   /* Protocol domain */
   in_addr.sin_addr.s_addr = htonl(INADDR_ANY);    /* Use wildcard IP address */
   in_addr.sin_port = htons(atoi(argv[1]));	   /* UDP port # of socket */

   /* ---
      Here goes the binding...
      --- */
   if (bind(s, (struct sockaddr *)&in_addr, sizeof(in_addr)) == -1)
   { 
      printf("Error: bind to port = %s FAILED\n", argv[1]);
   }
   else
   { 
      struct sockaddr_in sock_addr;
      int len;

      printf("OK: bind to port = %s SUCCESS\n", argv[1]);

      len = sizeof(sock_addr);
      getsockname(s, (struct sockaddr *) &sock_addr, &len);
      printf("**** Bind was successful....\n");
      printf("Socket is bind to:\n");
      printf("  addr = %u\n", ntohl(sock_addr.sin_addr.s_addr) );
      printf("  port = %u\n", ntohs(sock_addr.sin_port) );

   }
}