/*	Copyright (c) 1990 UNIX System Laboratories, Inc.	*/
/*	Copyright (c) 1984, 1986, 1987, 1988, 1989, 1990 AT&T	*/
/*	  All Rights Reserved  	*/

/*	THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF     	*/
/*	UNIX System Laboratories, Inc.                     	*/
/*	The copyright notice above does not evidence any   	*/
/*	actual or intended publication of such source code.	*/

#ident	"@(#)libinet:bindresvport.c	1.2.4.1"

/*
 * +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * 		PROPRIETARY NOTICE (Combined)
 * 
 * This source code is unpublished proprietary information
 * constituting, or derived under license from AT&T's UNIX(r) System V.
 * In addition, portions of such source code were derived from Berkeley
 * 4.3 BSD under license from the Regents of the University of
 * California.
 * 
 * 
 * 
 * 		Copyright Notice 
 * 
 * Notice of copyright on this source code product does not indicate 
 * publication.
 * 
 * 	(c) 1986,1987,1988.1989  Sun Microsystems, Inc
 * 	(c) 1983,1984,1985,1986,1987,1988,1989  AT&T.
 * 	          All rights reserved.
 *  
 */

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

#ifdef SYSV
#define bzero(s, len)	memset(s, 0, len)
#endif SYSV


/*
 * Bind a socket to a privileged IP port
 */
bindresvport(sd, sin)
	int sd;
	struct sockaddr_in *sin;
{
	int res;
	static short port;
	struct sockaddr_in myaddr;
	extern int errno;
	int i;

#define STARTPORT 600
#define ENDPORT (IPPORT_RESERVED - 1)
#define NPORTS	(ENDPORT - STARTPORT + 1)

	if (sin == (struct sockaddr_in *)0) {
		sin = &myaddr;
		bzero(sin, sizeof (*sin));
		sin->sin_family = AF_INET;
	} else if (sin->sin_family != AF_INET) {
		errno = EPFNOSUPPORT;
		return (-1);
	}
	if (port == 0) {
		port = (getpid() % NPORTS) + STARTPORT;
	}
	res = -1;
	errno = EADDRINUSE;
	for (i = 0; i < NPORTS && res < 0 && errno == EADDRINUSE; i++) {
		sin->sin_port = htons(port++);
		if (port > ENDPORT) {
			port = STARTPORT;
		}
		res = bind(sd, sin, sizeof(struct sockaddr_in));
	}
	return (res);
}
