#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include "socket.h"

extern int errno ;

#define QLEN       25                 // queue length for incoming TCP connections

// get_ssock ( int port_num, char *sock_type ) -- creates a server socket, binds it
// port_num, and listens for connections
int get_ssock ( int port_num, char *sock_type )
{
   struct sockaddr_in sin ;

   int stype ; // socket type
   int sock ;  // socket file descriptor
   int val ;   // temporary value holder

   if ( strcmp ( sock_type, "udp" ) == 0 ) {
      stype = SOCK_DGRAM ;
   } else {
      stype = SOCK_STREAM ;
   }

   // create socket
   sock = socket ( AF_INET, stype, 0 ) ;
   if ( sock < 0 ) {
      fprintf ( stderr, "Can't create socket: %s\n", strerror(errno) ) ;
      exit(1) ;
   }

   memset ( &sin, 0, sizeof(sin) ) ;
   sin.sin_family = AF_INET ;
   sin.sin_addr.s_addr = INADDR_ANY ;
   sin.sin_port = htons ( (short) port_num ) ;

   // try to bind to port_num
   val = bind ( sock, (struct sockaddr *)&sin, sizeof(sin) ) ;
   if ( val < 0 ) {
      fprintf ( stderr, "Can't bind socket: %s\n", strerror(errno) ) ;
      exit(1) ;
   }

   // try to listen if it is a tcp socket
   if ( stype == SOCK_STREAM ) {
      val = listen ( sock, QLEN ) ;
      if ( val < 0 ) {
         fprintf ( stderr, "Can't listen on socket: %s\n", strerror(errno) ) ;
         exit(1) ;
      }
   }

   return sock ;
}

/* get_csock ( const char *host, int port_num, char *sock_type ) -- creates 
 * a client (active) socket, and tries to connect to port_num port of host.
 * sock_type specifies the socket type to be used, currently accepted
 * options are "tcp" and "upd".
 */
int get_csock ( const char *host, int port_num, char *sock_type )
{
   struct sockaddr_in sin ;
   struct hostent *hen ;

   int sock, stype, rval ;

   if ( strcmp ( sock_type, "udp" ) == 0 ) {
      stype = SOCK_DGRAM ;
   } else {
      stype = SOCK_STREAM ;
   }

   sock = socket ( AF_INET, stype, 0 ) ;

   if ( sock < 0 ) {
      return -1;
   }

   memset ( &sin, 0, sizeof(sin) ) ;

   sin.sin_family = AF_INET ;
   sin.sin_port = htons ( (short) port_num ) ;

   if ( (hen = gethostbyname(host)) ) { // first try alpha-numerical address
      memcpy ( &sin.sin_addr, hen->h_addr, hen->h_length ) ;
   } else { // doesn't seem to be alpha-numerical, try dotted decimal
      if ( inet_pton ( AF_INET, host, &sin.sin_addr ) < 1 ) {
         return -1;
      }
   }

   rval = connect ( sock, (struct sockaddr *) &sin, sizeof(sin) ) ;

   if ( rval < 0 ) {
      return -1;
   }

   return sock ;
}