rresvport.c revision 181111 
1/* $OpenBSD: rresvport.c,v 1.9 2005/11/10 10:00:17 espie Exp $ */
2/*
3 * Copyright (c) 1995, 1996, 1998 Theo de Raadt.  All rights reserved.
4 * Copyright (c) 1983, 1993, 1994
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32/* OPENBSD ORIGINAL: lib/libc/net/rresvport.c */
33
34#include "includes.h"
35
36#ifndef HAVE_RRESVPORT_AF
37
38#include <sys/types.h>
39#include <sys/socket.h>
40
41#include <netinet/in.h>
42#include <arpa/inet.h>
43
44#include <errno.h>
45#include <stdlib.h>
46#include <string.h>
47#include <unistd.h>
48
49#if 0
50int
51rresvport(int *alport)
52{
53	return rresvport_af(alport, AF_INET);
54}
55#endif
56
57int
58rresvport_af(int *alport, sa_family_t af)
59{
60	struct sockaddr_storage ss;
61	struct sockaddr *sa;
62	u_int16_t *portp;
63	int s;
64	socklen_t salen;
65
66	memset(&ss, '\0', sizeof ss);
67	sa = (struct sockaddr *)&ss;
68
69	switch (af) {
70	case AF_INET:
71		salen = sizeof(struct sockaddr_in);
72		portp = &((struct sockaddr_in *)sa)->sin_port;
73		break;
74	case AF_INET6:
75		salen = sizeof(struct sockaddr_in6);
76		portp = &((struct sockaddr_in6 *)sa)->sin6_port;
77		break;
78	default:
79		errno = EPFNOSUPPORT;
80		return (-1);
81	}
82	sa->sa_family = af;
83
84	s = socket(af, SOCK_STREAM, 0);
85	if (s < 0)
86		return (-1);
87
88	*portp = htons(*alport);
89	if (*alport < IPPORT_RESERVED - 1) {
90		if (bind(s, sa, salen) >= 0)
91			return (s);
92		if (errno != EADDRINUSE) {
93			(void)close(s);
94			return (-1);
95		}
96	}
97
98	*portp = 0;
99	sa->sa_family = af;
100	if (bindresvport_sa(s, sa) == -1) {
101		(void)close(s);
102		return (-1);
103	}
104	*alport = ntohs(*portp);
105	return (s);
106}
107
108#endif /* HAVE_RRESVPORT_AF */
109