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 #pragma ident	"%Z%%M%	%I%	%E% SMI"
23 
24 /*
25  * get_myaddress.c
26  *
27  * Get client's IP address via ioctl.  This avoids using the NIS.
28  * Copyright (C) 1990, Sun Microsystems, Inc.
29  */
30 
31 #include <rpc/types.h>
32 #include <rpc/pmap_prot.h>
33 #include <sys/socket.h>
34 #include <sys/sockio.h>
35 #include <stdio.h>
36 #include <net/if.h>
37 #include <sys/ioctl.h>
38 #include <arpa/inet.h>
39 #include <netinet/in.h>
40 #include <syslog.h>
41 #include <malloc.h>
42 #include <unistd.h>
43 #include <stropts.h>
44 #include <stdlib.h>
45 #include <errno.h>
46 
47 /*
48  * don't use gethostbyname, which would invoke NIS
49  */
50 void
get_myaddress(struct sockaddr_in * addr)51 get_myaddress(struct sockaddr_in *addr)
52 {
53 	int s;
54 	struct ifconf ifc;
55 	struct ifreq ifreq, *ifr;
56 	int len, numifs;
57 	int ret;
58 
59 	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
60 	    syslog(LOG_ERR, "get_myaddress: socket: %m");
61 	    exit(1);
62 	}
63 
64 	do {
65 		ret = ioctl(s, SIOCGIFNUM, (char *)&numifs);
66 	} while (ret < 0 && (errno == EINTR || errno == EAGAIN));
67 	if (ret < 0) {
68 		syslog(LOG_ERR, "get_myaddress: ioctl: %m");
69 		exit(1);
70 	}
71 
72 	ifc.ifc_len = numifs * sizeof (struct ifreq);
73 	if ((ifc.ifc_buf = (caddr_t)malloc(ifc.ifc_len)) == NULL) {
74 		syslog(LOG_ERR, "get_myaddress: malloc: %m");
75 		exit(1);
76 	}
77 
78 	do {
79 		ret = ioctl(s, SIOCGIFCONF, (char *)&ifc);
80 	} while (ret < 0 && (errno == EINTR || errno == EAGAIN));
81 	if (ret < 0) {
82 		syslog(LOG_ERR,
83 		    "get_myaddress: ioctl (get interface configuration): %m");
84 		exit(1);
85 	}
86 
87 	/*
88 	 * set default to loopback in case nothing is found.
89 	 */
90 	addr->sin_family = AF_INET;
91 	addr->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
92 	addr->sin_port = htons(PMAPPORT);
93 
94 	ifr = ifc.ifc_req;
95 	for (len = ifc.ifc_len; len > 0; len -= sizeof (ifreq), ifr++) {
96 		ifreq = *ifr;
97 		do {
98 			ret = ioctl(s, SIOCGIFFLAGS, (char *)&ifreq);
99 		} while (ret < 0 && (errno == EINTR || errno == EAGAIN));
100 		if (ret < 0) {
101 			syslog(LOG_ERR, "get_myaddress: ioctl: %m");
102 			exit(1);
103 		}
104 		if (ifr->ifr_addr.sa_family != AF_INET)
105 			continue;
106 		if ((ifreq.ifr_flags & IFF_UP) == 0)
107 			continue;
108 		if (ifreq.ifr_flags & IFF_LOOPBACK)
109 			continue;
110 		if ((ifreq.ifr_flags & (IFF_MULTICAST | IFF_BROADCAST)) == 0)
111 			continue;
112 		*addr = *((struct sockaddr_in *)&ifr->ifr_addr);
113 		addr->sin_port = htons(PMAPPORT);
114 		break;
115 	}
116 	free(ifc.ifc_buf);
117 	(void) close(s);
118 }
119