1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
28 /* All Rights Reserved */
29
30 /*
31 * Portions of this source code were derived from Berkeley 4.3 BSD
32 * under license from the Regents of the University of California.
33 */
34
35 #include <sys/types.h>
36 #include <errno.h>
37 #include <sys/socket.h>
38 #include <netinet/in.h>
39 #include <netinet/tcp.h>
40 #include <netinet/udp.h>
41 #include <string.h>
42 #include <unistd.h>
43
44 #ifdef SYSV
45 #define bzero(s, len) (void) memset((s), 0, (len))
46 #endif
47
48
49 /*
50 * Bind a socket to a privileged IP port
51 */
52 int
bindresvport(int sd,struct sockaddr_in * sin)53 bindresvport(int sd, struct sockaddr_in *sin)
54 {
55 struct sockaddr_in myaddr;
56 struct sockaddr_in *bindaddr;
57 int level, optname;
58 int optval, len;
59 int ret;
60
61 bindaddr = sin;
62 if (bindaddr == (struct sockaddr_in *)0) {
63 bindaddr = &myaddr;
64 bzero(bindaddr, sizeof (*bindaddr));
65 bindaddr->sin_family = AF_INET;
66 } else if (bindaddr->sin_family != AF_INET) {
67 errno = EPFNOSUPPORT;
68 return (-1);
69 }
70
71 len = sizeof (optval);
72 if (getsockopt(sd, SOL_SOCKET, SO_TYPE, &optval, &len) < 0) {
73 return (-1);
74 }
75 /*
76 * Use *_ANONPRIVBIND to ask the kernel to pick a port in the
77 * priviledged range for us.
78 */
79 if (optval == SOCK_STREAM) {
80 level = IPPROTO_TCP;
81 optname = TCP_ANONPRIVBIND;
82 } else if (optval == SOCK_DGRAM) {
83 level = IPPROTO_UDP;
84 optname = UDP_ANONPRIVBIND;
85 } else {
86 errno = EPROTONOSUPPORT;
87 return (-1);
88 }
89
90 optval = 1;
91 if (setsockopt(sd, level, optname, &optval, sizeof (optval)) < 0) {
92 return (-1);
93 }
94
95 bindaddr->sin_port = 0;
96 ret = bind(sd, (struct sockaddr *)bindaddr,
97 sizeof (struct sockaddr_in));
98
99 /*
100 * Always turn off the option when we are done. Note that by doing
101 * this, if the caller has set this option before calling
102 * bindresvport(), it will be unset. But this should never happen...
103 */
104 optval = 0;
105 (void) setsockopt(sd, level, optname, &optval, sizeof (optval));
106
107 if (ret >= 0 && sin != NULL) {
108 /*
109 * Historical note:
110 *
111 * Past versions of this bindresvport() code have
112 * returned with the reserved port number bound
113 * filled in its "sin" parameter (if passed in), perhaps
114 * "accidently" because of the structure of historical code.
115 *
116 * This is not documented but the behavior is
117 * explicitly retained here for compatibility to minimize
118 * risk to applications, even though it is not clear if this
119 * was a design intent.
120 */
121 len = sizeof (struct sockaddr_in);
122 (void) getsockname(sd, (struct sockaddr *)bindaddr, &len);
123 }
124 return (ret);
125 }
126