xref: /openbsd/lib/libc/net/rresvport.c (revision 133306f0)
1 /*
2  * Copyright (c) 1995, 1996, 1998 Theo de Raadt.  All rights reserved.
3  * Copyright (c) 1983, 1993, 1994
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. All advertising materials mentioning features or use of this software
15  *    must display the following acknowledgement:
16  *	This product includes software developed by the University of
17  *	California, Berkeley and its contributors.
18  *	This product includes software developed by Theo de Raadt.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #if defined(LIBC_SCCS) && !defined(lint)
37 static char *rcsid = "$OpenBSD: rresvport.c,v 1.5 2000/01/26 03:43:20 deraadt Exp $";
38 #endif /* LIBC_SCCS and not lint */
39 
40 #include <sys/param.h>
41 #include <sys/socket.h>
42 #include <sys/stat.h>
43 
44 #include <netinet/in.h>
45 #include <arpa/inet.h>
46 
47 #include <signal.h>
48 #include <fcntl.h>
49 #include <netdb.h>
50 #include <unistd.h>
51 #include <pwd.h>
52 #include <errno.h>
53 #include <stdio.h>
54 #include <ctype.h>
55 #include <string.h>
56 #include <syslog.h>
57 #include <stdlib.h>
58 #include <netgroup.h>
59 
60 int
61 rresvport(alport)
62 	int *alport;
63 {
64 	return rresvport_af(alport, AF_INET);
65 }
66 
67 
68 int
69 rresvport_af(alport, af)
70 	int *alport;
71 	int af;
72 {
73 	struct sockaddr_storage ss;
74 	struct sockaddr *sa;
75 	u_int16_t *portp;
76 	int s;
77 
78 	bzero(&ss, sizeof ss);
79 	sa = (struct sockaddr *)&ss;
80 
81 	switch (af) {
82 	case AF_INET:
83 		sa->sa_len = sizeof(struct sockaddr_in);
84 		portp = &((struct sockaddr_in *)sa)->sin_port;
85 		break;
86 	case AF_INET6:
87 		sa->sa_len = sizeof(struct sockaddr_in6);
88 		portp = &((struct sockaddr_in6 *)sa)->sin6_port;
89 		break;
90 	default:
91 		errno = EPFNOSUPPORT;
92 		return (-1);
93 	}
94 	sa->sa_family = af;
95 
96 	s = socket(af, SOCK_STREAM, 0);
97 	if (s < 0)
98 		return (-1);
99 
100 	*portp = htons(*alport);
101 	if (*alport < IPPORT_RESERVED - 1) {
102 		if (bind(s, sa, sa->sa_len) >= 0)
103 			return (s);
104 		if (errno != EADDRINUSE) {
105 			(void)close(s);
106 			return (-1);
107 		}
108 	}
109 
110 	*portp = 0;
111 	sa->sa_family = af;
112 	if (bindresvport_sa(s, sa) == -1) {
113 		(void)close(s);
114 		return (-1);
115 	}
116 	*alport = ntohs(*portp);
117 	return (s);
118 }
119