xref: /illumos-gate/usr/src/ucblib/librpcsoc/get_myaddress.c (revision 8c0b080c8ed055a259d8cd26b9f005211c6a9753)
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 /*
24  * get_myaddress.c
25  *
26  * Get client's IP address via ioctl.  This avoids using the NIS.
27  * Copyright (C) 1990, Sun Microsystems, Inc.
28  */
29 
30 #include <rpc/types.h>
31 #include <rpc/pmap_prot.h>
32 #include <sys/socket.h>
33 #include <sys/sockio.h>
34 #include <stdio.h>
35 #include <net/if.h>
36 #include <sys/ioctl.h>
37 #include <arpa/inet.h>
38 #include <netinet/in.h>
39 #include <syslog.h>
40 #include <malloc.h>
41 #include <unistd.h>
42 #include <stropts.h>
43 #include <stdlib.h>
44 #include <errno.h>
45 
46 /*
47  * don't use gethostbyname, which would invoke NIS
48  */
49 void
get_myaddress(struct sockaddr_in * addr)50 get_myaddress(struct sockaddr_in *addr)
51 {
52 	int s;
53 	struct ifconf ifc;
54 	struct ifreq ifreq, *ifr;
55 	int len, numifs;
56 	int ret;
57 
58 	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
59 	    syslog(LOG_ERR, "get_myaddress: socket: %m");
60 	    exit(1);
61 	}
62 
63 	do {
64 		ret = ioctl(s, SIOCGIFNUM, (char *)&numifs);
65 	} while (ret < 0 && (errno == EINTR || errno == EAGAIN));
66 	if (ret < 0) {
67 		syslog(LOG_ERR, "get_myaddress: ioctl: %m");
68 		exit(1);
69 	}
70 
71 	ifc.ifc_len = numifs * sizeof (struct ifreq);
72 	if ((ifc.ifc_buf = (caddr_t)malloc(ifc.ifc_len)) == NULL) {
73 		syslog(LOG_ERR, "get_myaddress: malloc: %m");
74 		exit(1);
75 	}
76 
77 	do {
78 		ret = ioctl(s, SIOCGIFCONF, (char *)&ifc);
79 	} while (ret < 0 && (errno == EINTR || errno == EAGAIN));
80 	if (ret < 0) {
81 		syslog(LOG_ERR,
82 		    "get_myaddress: ioctl (get interface configuration): %m");
83 		exit(1);
84 	}
85 
86 	/*
87 	 * set default to loopback in case nothing is found.
88 	 */
89 	addr->sin_family = AF_INET;
90 	addr->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
91 	addr->sin_port = htons(PMAPPORT);
92 
93 	ifr = ifc.ifc_req;
94 	for (len = ifc.ifc_len; len > 0; len -= sizeof (ifreq), ifr++) {
95 		ifreq = *ifr;
96 		do {
97 			ret = ioctl(s, SIOCGIFFLAGS, (char *)&ifreq);
98 		} while (ret < 0 && (errno == EINTR || errno == EAGAIN));
99 		if (ret < 0) {
100 			syslog(LOG_ERR, "get_myaddress: ioctl: %m");
101 			exit(1);
102 		}
103 		if (ifr->ifr_addr.sa_family != AF_INET)
104 			continue;
105 		if ((ifreq.ifr_flags & IFF_UP) == 0)
106 			continue;
107 		if (ifreq.ifr_flags & IFF_LOOPBACK)
108 			continue;
109 		if ((ifreq.ifr_flags & (IFF_MULTICAST | IFF_BROADCAST)) == 0)
110 			continue;
111 		*addr = *((struct sockaddr_in *)&ifr->ifr_addr);
112 		addr->sin_port = htons(PMAPPORT);
113 		break;
114 	}
115 	free(ifc.ifc_buf);
116 	(void) close(s);
117 }
118