inet.c revision 1.15 
1/*	$OpenBSD: inet.c,v 1.15 2004/01/21 00:30:15 jfb Exp $	*/
2
3/*
4 * Copyright (c) 1994, 1995, 1996, 1997, 1998
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the Computer Systems
18 *	Engineering Group at Lawrence Berkeley Laboratory.
19 * 4. Neither the name of the University nor of the Laboratory may be used
20 *    to endorse or promote products derived from this software without
21 *    specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#ifndef lint
37static const char rcsid[] =
38    "@(#) $Header: /usr/local/opengrok/home/cvs-mirror/mirrors/openbsd/src/lib/libpcap/inet.c,v 1.15 2004/01/21 00:30:15 jfb Exp $ (LBL)";
39#endif
40
41#include <sys/param.h>
42#include <sys/file.h>
43#include <sys/ioctl.h>
44#include <sys/socket.h>
45#ifdef HAVE_SYS_SOCKIO_H
46#include <sys/sockio.h>
47#endif
48#include <sys/time.h>				/* concession to AIX */
49
50struct mbuf;
51struct rtentry;
52
53#include <net/if.h>
54#include <netinet/in.h>
55
56#include <ctype.h>
57#include <errno.h>
58#include <memory.h>
59#include <stdio.h>
60#include <stdlib.h>
61#include <string.h>
62#include <unistd.h>
63#ifdef HAVE_IFADDRS_H
64#include <ifaddrs.h>
65#endif
66
67#include "pcap-int.h"
68
69#ifdef HAVE_OS_PROTO_H
70#include "os-proto.h"
71#endif
72
73/* Not all systems have IFF_LOOPBACK */
74#ifdef IFF_LOOPBACK
75#define ISLOOPBACK(p) ((p)->ifr_flags & IFF_LOOPBACK)
76#else
77#define ISLOOPBACK(p) ((p)->ifr_name[0] == 'l' && (p)->ifr_name[1] == 'o' && \
78    (isdigit((p)->ifr_name[2]) || (p)->ifr_name[2] == '\0'))
79#endif
80
81/*
82 * Return the name of a network interface attached to the system, or NULL
83 * if none can be found.  The interface must be configured up; the
84 * lowest unit number is preferred; loopback is ignored.
85 */
86char *
87pcap_lookupdev(errbuf)
88	register char *errbuf;
89{
90#ifdef HAVE_IFADDRS_H
91	struct ifaddrs *ifap, *ifa, *mp;
92	int n, minunit;
93	char *cp;
94	static char device[IF_NAMESIZE + 1];
95
96	if (getifaddrs(&ifap) != 0) {
97		(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
98		    "getifaddrs: %s", pcap_strerror(errno));
99		return NULL;
100	}
101
102	mp = NULL;
103	minunit = 666;
104	for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
105		if ((ifa->ifa_flags & IFF_UP) == 0)
106			continue;
107#ifdef IFF_LOOPBACK
108		if ((ifa->ifa_flags & IFF_LOOPBACK) != 0)
109			continue;
110#else
111		if (strncmp(ifa->ifa_name, "lo", 2) == 0 &&
112		    (ifa->ifa_name[2] == '\0' || isdigit(ifa->ifa_name[2]))) {
113			continue;
114		}
115#endif
116
117		for (cp = ifa->ifa_name; !isdigit(*cp); ++cp)
118			continue;
119		n = atoi(cp);
120		if (n < minunit) {
121			minunit = n;
122			mp = ifa;
123		}
124	}
125	if (mp == NULL) {
126		(void)strlcpy(errbuf, "no suitable device found",
127		    PCAP_ERRBUF_SIZE);
128		freeifaddrs(ifap);
129		return (NULL);
130	}
131
132	(void)strlcpy(device, mp->ifa_name, sizeof(device));
133	freeifaddrs(ifap);
134	return (device);
135#else
136	register int fd, minunit, n;
137	register char *cp;
138	register struct ifreq *ifrp, *ifend, *ifnext, *mp;
139	struct ifconf ifc;
140	struct ifreq ibuf[16], ifr;
141	static char device[sizeof(ifrp->ifr_name) + 1];
142
143	fd = socket(AF_INET, SOCK_DGRAM, 0);
144	if (fd < 0) {
145		(void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
146		    pcap_strerror(errno));
147		return (NULL);
148	}
149	ifc.ifc_len = sizeof ibuf;
150	ifc.ifc_buf = (caddr_t)ibuf;
151
152	memset((char *)ibuf, 0, sizeof(ibuf));
153	if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 ||
154	    ifc.ifc_len < sizeof(struct ifreq)) {
155		(void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFCONF: %s",
156		    pcap_strerror(errno));
157		(void)close(fd);
158		return (NULL);
159	}
160	ifrp = ibuf;
161	ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);
162
163	mp = NULL;
164	minunit = 666;
165	for (; ifrp < ifend; ifrp = ifnext) {
166#ifdef HAVE_SOCKADDR_SA_LEN
167		n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
168		if (n < sizeof(*ifrp))
169			ifnext = ifrp + 1;
170		else
171			ifnext = (struct ifreq *)((char *)ifrp + n);
172		if (ifrp->ifr_addr.sa_family != AF_INET)
173			continue;
174#else
175		ifnext = ifrp + 1;
176#endif
177		/*
178		 * Need a template to preserve address info that is
179		 * used below to locate the next entry.  (Otherwise,
180		 * SIOCGIFFLAGS stomps over it because the requests
181		 * are returned in a union.)
182		 */
183		(void)strlcpy(ifr.ifr_name, ifrp->ifr_name,
184		    sizeof(ifr.ifr_name));
185		if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) {
186			if (errno == ENXIO)
187				continue;
188			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
189			    "SIOCGIFFLAGS: %.*s: %s",
190			    (int)sizeof(ifr.ifr_name), ifr.ifr_name,
191			    pcap_strerror(errno));
192			(void)close(fd);
193			return (NULL);
194		}
195
196		/* Must be up and not the loopback */
197		if ((ifr.ifr_flags & IFF_UP) == 0 || ISLOOPBACK(&ifr))
198			continue;
199
200		for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp)
201			continue;
202		n = atoi(cp);
203		if (n < minunit) {
204			minunit = n;
205			mp = ifrp;
206		}
207	}
208	(void)close(fd);
209	if (mp == NULL) {
210		(void)strlcpy(errbuf, "no suitable device found",
211		    PCAP_ERRBUF_SIZE);
212		return (NULL);
213	}
214
215	(void)strlcpy(device, mp->ifr_name, sizeof(device));
216	return (device);
217#endif
218}
219
220int
221pcap_lookupnet(device, netp, maskp, errbuf)
222	register char *device;
223	register bpf_u_int32 *netp, *maskp;
224	register char *errbuf;
225{
226	register int fd;
227	register struct sockaddr_in *sin;
228	struct ifreq ifr;
229
230	fd = socket(AF_INET, SOCK_DGRAM, 0);
231	if (fd < 0) {
232		(void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
233		    pcap_strerror(errno));
234		return (-1);
235	}
236	memset(&ifr, 0, sizeof(ifr));
237#ifdef linux
238	/* XXX Work around Linux kernel bug */
239	ifr.ifr_addr.sa_family = AF_INET;
240#endif
241	(void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
242	if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
243		if (errno == EADDRNOTAVAIL) {
244			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
245			    "%s: no IPv4 address assigned", device);
246		} else {
247			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
248			    "SIOCGIFADDR: %s: %s",
249			    device, pcap_strerror(errno));
250		}
251		(void)close(fd);
252		return (-1);
253	}
254	sin = (struct sockaddr_in *)&ifr.ifr_addr;
255	*netp = sin->sin_addr.s_addr;
256	if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
257		(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
258		    "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno));
259		(void)close(fd);
260		return (-1);
261	}
262	(void)close(fd);
263	*maskp = sin->sin_addr.s_addr;
264	if (*maskp == 0) {
265		if (IN_CLASSA(*netp))
266			*maskp = IN_CLASSA_NET;
267		else if (IN_CLASSB(*netp))
268			*maskp = IN_CLASSB_NET;
269		else if (IN_CLASSC(*netp))
270			*maskp = IN_CLASSC_NET;
271		else {
272			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
273			    "inet class for 0x%x unknown", *netp);
274			return (-1);
275		}
276	}
277	*netp &= *maskp;
278	return (0);
279}
280