1 /* This file has be substantially modified from the original OpenBSD source */
2
3 /* $OpenBSD: bindresvport.c,v 1.17 2005/12/21 01:40:22 millert 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 */
52 int
bindresvport_sa(int sd,struct sockaddr * sa)53 bindresvport_sa(int sd, struct sockaddr *sa)
54 {
55 int error, af;
56 struct sockaddr_storage myaddr;
57 struct sockaddr_in *in;
58 struct sockaddr_in6 *in6;
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 salen = sizeof(myaddr);
68
69 if (getsockname(sd, sa, &salen) == -1)
70 return -1; /* errno is correctly set */
71
72 af = sa->sa_family;
73 memset(&myaddr, 0, salen);
74 } else
75 af = sa->sa_family;
76
77 if (af == AF_INET) {
78 in = (struct sockaddr_in *)sa;
79 salen = sizeof(struct sockaddr_in);
80 portp = &in->sin_port;
81 } else if (af == AF_INET6) {
82 in6 = (struct sockaddr_in6 *)sa;
83 salen = sizeof(struct sockaddr_in6);
84 portp = &in6->sin6_port;
85 } else {
86 errno = EPFNOSUPPORT;
87 return (-1);
88 }
89 sa->sa_family = af;
90
91 port = ntohs(*portp);
92 if (port == 0)
93 port = arc4random_uniform(NPORTS) + STARTPORT;
94
95 /* Avoid warning */
96 error = -1;
97
98 for(i = 0; i < NPORTS; i++) {
99 *portp = htons(port);
100
101 error = bind(sd, sa, salen);
102
103 /* Terminate on success */
104 if (error == 0)
105 break;
106
107 /* Terminate on errors, except "address already in use" */
108 if ((error < 0) && !((errno == EADDRINUSE) || (errno == EINVAL)))
109 break;
110
111 port++;
112 if (port > ENDPORT)
113 port = STARTPORT;
114 }
115
116 return (error);
117 }
118
119 #endif /* HAVE_BINDRESVPORT_SA */
120