bindresvport.c revision 181110
1/* This file has be substantially modified from the original OpenBSD source */
2
3/*	$OpenBSD: bindresvport.c,v 1.16 2005/04/01 07:44:03 otto Exp $	*/
4
5/*
6 * Copyright 1996, Jason Downs.  All rights reserved.
7 * Copyright 1998, Theo de Raadt.  All rights reserved.
8 * Copyright 2000, Damien Miller.  All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31/* OPENBSD ORIGINAL: lib/libc/rpc/bindresvport.c */
32
33#include "includes.h"
34
35#ifndef HAVE_BINDRESVPORT_SA
36#include <sys/types.h>
37#include <sys/socket.h>
38
39#include <netinet/in.h>
40#include <arpa/inet.h>
41
42#include <errno.h>
43#include <string.h>
44
45#define STARTPORT 600
46#define ENDPORT (IPPORT_RESERVED - 1)
47#define NPORTS	(ENDPORT - STARTPORT + 1)
48
49/*
50 * Bind a socket to a privileged IP port
51 */
52int
53bindresvport_sa(int sd, struct sockaddr *sa)
54{
55	int error, af;
56	struct sockaddr_storage myaddr;
57	struct sockaddr_in *sin;
58	struct sockaddr_in6 *sin6;
59	u_int16_t *portp;
60	u_int16_t port;
61	socklen_t salen;
62	int i;
63
64	if (sa == NULL) {
65		memset(&myaddr, 0, sizeof(myaddr));
66		sa = (struct sockaddr *)&myaddr;
67
68		if (getsockname(sd, sa, &salen) == -1)
69			return -1;	/* errno is correctly set */
70
71		af = sa->sa_family;
72		memset(&myaddr, 0, salen);
73	} else
74		af = sa->sa_family;
75
76	if (af == AF_INET) {
77		sin = (struct sockaddr_in *)sa;
78		salen = sizeof(struct sockaddr_in);
79		portp = &sin->sin_port;
80	} else if (af == AF_INET6) {
81		sin6 = (struct sockaddr_in6 *)sa;
82		salen = sizeof(struct sockaddr_in6);
83		portp = &sin6->sin6_port;
84	} else {
85		errno = EPFNOSUPPORT;
86		return (-1);
87	}
88	sa->sa_family = af;
89
90	port = ntohs(*portp);
91	if (port == 0)
92		port = (arc4random() % NPORTS) + STARTPORT;
93
94	/* Avoid warning */
95	error = -1;
96
97	for(i = 0; i < NPORTS; i++) {
98		*portp = htons(port);
99
100		error = bind(sd, sa, salen);
101
102		/* Terminate on success */
103		if (error == 0)
104			break;
105
106		/* Terminate on errors, except "address already in use" */
107		if ((error < 0) && !((errno == EADDRINUSE) || (errno == EINVAL)))
108			break;
109
110		port++;
111		if (port > ENDPORT)
112			port = STARTPORT;
113	}
114
115	return (error);
116}
117
118#endif /* HAVE_BINDRESVPORT_SA */
119