1 /* $OpenBSD: get_myaddress.c,v 1.16 2020/12/30 18:56:35 benno Exp $ */
2
3 /*
4 * Copyright (c) 2010, Oracle America, Inc.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met:
9 *
10 * * Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * * Redistributions in binary form must reproduce the above
13 * copyright notice, this list of conditions and the following
14 * disclaimer in the documentation and/or other materials
15 * provided with the distribution.
16 * * Neither the name of the "Oracle America, Inc." nor the names of its
17 * contributors may be used to endorse or promote products derived
18 * from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
25 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
27 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34 /*
35 * get_myaddress.c
36 *
37 * Get client's IP address via ioctl. This avoids using the yellowpages.
38 */
39
40 #include <rpc/types.h>
41 #include <rpc/xdr.h>
42 #include <rpc/pmap_prot.h>
43 #include <rpc/rpc.h>
44 #include <sys/socket.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <unistd.h>
48 #include <net/if.h>
49 #include <netinet/in.h>
50 #include <ifaddrs.h>
51
52 /*
53 * don't use gethostbyname, which would invoke yellow pages
54 *
55 * Avoid loopback interfaces. We return information from a loopback
56 * interface only if there are no other possible interfaces.
57 */
58 int
get_myaddress(struct sockaddr_in * addr)59 get_myaddress(struct sockaddr_in *addr)
60 {
61 struct ifaddrs *ifap, *ifa;
62 int loopback = 0, gotit = 0;
63
64 if (getifaddrs(&ifap) != 0)
65 return (-1);
66
67 again:
68 for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
69 if ((ifa->ifa_flags & IFF_UP) &&
70 ifa->ifa_addr != NULL &&
71 ifa->ifa_addr->sa_family == AF_INET &&
72 (loopback == 1 && (ifa->ifa_flags & IFF_LOOPBACK))) {
73 *addr = *((struct sockaddr_in *)ifa->ifa_addr);
74 addr->sin_port = htons(PMAPPORT);
75 gotit = 1;
76 break;
77 }
78 }
79 if (gotit == 0 && loopback == 0) {
80 loopback = 1;
81 goto again;
82 }
83 freeifaddrs(ifap);
84 return (0);
85 }
86 DEF_WEAK(get_myaddress);
87