/* connectsock.c - connectsock */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#ifndef INADDR_NONE
#define INADDR_NONE   0xffffffff
#endif   /* INADDR_NONE */

extern int	errno;
extern char	*sys_errlist[];

/* u_short	htons(u_short);
u_long inet_addr();  */

/*----------------------------------------------------------------
 * connectsock - allocate & connect a socket using TCP or UDP
 *----------------------------------------------------------------
*/


int connectsock( char *host, char *service, char *protocol )
{

struct hostent  *phe;	/* pointer to host information entry */
struct servent  *pse;	/* pointer to service information entry */
struct protoent *ppe;	/* pointer to protocol information entry */
struct sockaddr_in sin;	/* an inetrnet endpoint address		*/
int s, type;

	bzero ((char *)&sin, sizeof(sin));
	sin.sin_family = AF_INET;

/*	map service name to port number  */
	if(pse = getservbyname(service,protocol))
		sin.sin_port = pse->s_port;

	else if ((sin.sin_port = htons((u_short)atoi(service))) == 0)
		errexit("can't get \"%s\" service entry\n", service);

/*	map host name to IP address, allowing for dotted notation */
	if (phe = gethostbyname (host))
		bcopy(phe->h_addr, (char *)&sin.sin_addr, phe->h_length);

	else if  ((sin.sin_addr.s_addr = inet_addr(host)) == INADDR_NONE)
		errexit("can't get \"%s\" host entry\n", host);

/*	map protocol name to protocol number */
	if((ppe = getprotobyname(protocol)) == 0)
		errexit("can't get \"%s\" protocol entry\n", protocol);

/*	use protocol to choose a socket type */
	if(strcmp(protocol, "udp") == 0)
		type = SOCK_DGRAM;

	else
		type = SOCK_STREAM;

/*	allocate a socket	*/
	s = socket(PF_INET, type, ppe->p_proto);

	if(s < 0)
		errexit("can't create socket: %s\n", sys_errlist[errno]);

/*	connect the socket	*/
	if(connect(s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
		errexit("can't connect to %s. %s: %s\n", host,service, 							   sys_errlist[errno]);

	return s;
}