/* passivesock.c - passivesock */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
extern int	errno;
extern char	*sys_errlist[];
/* u_short	htons(u_short);
u_long inet_addr();  */
u_short portbase = 0;

/*----------------------------------------------------------------
 * passivesock - allocate & bind a server socket using TCP or UDP
 *----------------------------------------------------------------
*/
int
passivesock(service, protocol, qlen )
char	*service;
char	*protocol;
int	qlen;
{
	struct servent  *pse;	/* pointer to service information entry */
	struct protoent *ppe;	/* pointer to protocol information entry */
	struct sockaddr_in sin;	/* an internet endpoint address		*/
	int s, type;

	bzero ((char *)&sin, sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_addr.s_addr = INADDR_ANY;
/*	map service name to port number  */
	if(pse = getservbyname(service,protocol))
		sin.sin_port = htons(ntohs((u_short)pse->s_port) + portbase);
	else if ((sin.sin_port = htons((u_short)atoi(service))) == 0)
		errexit("can't get \"%s\" service entry\n", service);
/*	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]);
/* Bind the socket		*/
	if(bind(s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
		errexit("can't bind to %s port: %s\n",service,
			 sys_errlist[errno]);
	if(type == SOCK_STREAM && listen(s, qlen) < 0)
		errexit("can't listen on %s port:  %s\n", service,
			sys_errlist[errno]);
	return s;
}