/* lib/rpc/bindresvport.c */
/*
 * Copyright (c) 2010, Oracle America, Inc.
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *
 *     * Neither the name of the "Oracle America, Inc." nor the names of
 *       its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <gssrpc/rpc.h>
#include <errno.h>

/*
 * Bind a socket to a privileged IP port
 */
int
bindresvport(int sd, struct sockaddr_in *sockin)
{
	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 (sockin == (struct sockaddr_in *)0) {
		sockin = &myaddr;
		memset(sockin, 0, sizeof (*sockin));
		sockin->sin_family = AF_INET;
	} else if (sockin->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++) {
		sockin->sin_port = htons(port++);
		if (port > ENDPORT) {
			port = STARTPORT;
		}
		res = bind(sd, (struct sockaddr *) sockin,
			   sizeof(struct sockaddr_in));
	}
	return (res);
}