xref: /onnv-gate/usr/src/lib/libbc/libc/net/bindresvport.c (revision 722:636b850d4ee9)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 1987 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

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

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