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 */
58int
59get_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}
86DEF_WEAK(get_myaddress);
87