1/* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
2/*
3 * Copyright (c) 1994, 1995, 1996, 1997, 1998
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 *    must display the following acknowledgement:
16 *	This product includes software developed by the Computer Systems
17 *	Engineering Group at Lawrence Berkeley Laboratory.
18 * 4. Neither the name of the University nor of the Laboratory may be used
19 *    to endorse or promote products derived from this software without
20 *    specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#ifdef HAVE_CONFIG_H
36#include <config.h>
37#endif
38
39#include <sys/types.h>
40#include <sys/socket.h>
41#include <netinet/in.h>
42
43#include <net/if.h>
44
45#include <errno.h>
46#include <stdio.h>
47#include <stdlib.h>
48#include <string.h>
49#include <ifaddrs.h>
50
51#include "pcap-int.h"
52
53#ifdef HAVE_OS_PROTO_H
54#include "os-proto.h"
55#endif
56
57/*
58 * We don't do this on Solaris 11 and later, as it appears there aren't
59 * any AF_PACKET addresses on interfaces, so we don't need this, and
60 * we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>,
61 * and their definitions of some data structures collide.
62 */
63#if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
64# ifdef HAVE_NETPACKET_PACKET_H
65/* Linux distributions with newer glibc */
66#  include <netpacket/packet.h>
67# else /* HAVE_NETPACKET_PACKET_H */
68/* LynxOS, Linux distributions with older glibc */
69# ifdef __Lynx__
70/* LynxOS */
71#  include <netpacket/if_packet.h>
72# else /* __Lynx__ */
73/* Linux */
74#  include <linux/types.h>
75#  include <linux/if_packet.h>
76# endif /* __Lynx__ */
77# endif /* HAVE_NETPACKET_PACKET_H */
78#endif /* (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) */
79
80/*
81 * This is fun.
82 *
83 * In older BSD systems, socket addresses were fixed-length, and
84 * "sizeof (struct sockaddr)" gave the size of the structure.
85 * All addresses fit within a "struct sockaddr".
86 *
87 * In newer BSD systems, the socket address is variable-length, and
88 * there's an "sa_len" field giving the length of the structure;
89 * this allows socket addresses to be longer than 2 bytes of family
90 * and 14 bytes of data.
91 *
92 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
93 * variant of the old BSD scheme (with "struct sockaddr_storage" rather
94 * than "struct sockaddr"), and some use the new BSD scheme.
95 *
96 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
97 * macro that determines the size based on the address family.  Other
98 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
99 * but not in the final version).  On the latter systems, we explicitly
100 * check the AF_ type to determine the length; we assume that on
101 * all those systems we have "struct sockaddr_storage".
102 */
103#ifndef SA_LEN
104#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
105#define SA_LEN(addr)	((addr)->sa_len)
106#else /* HAVE_STRUCT_SOCKADDR_SA_LEN */
107#ifdef HAVE_STRUCT_SOCKADDR_STORAGE
108static size_t
109get_sa_len(struct sockaddr *addr)
110{
111	switch (addr->sa_family) {
112
113#ifdef AF_INET
114	case AF_INET:
115		return (sizeof (struct sockaddr_in));
116#endif
117
118#ifdef AF_INET6
119	case AF_INET6:
120		return (sizeof (struct sockaddr_in6));
121#endif
122
123#if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
124	case AF_PACKET:
125		return (sizeof (struct sockaddr_ll));
126#endif
127
128	default:
129		return (sizeof (struct sockaddr));
130	}
131}
132#define SA_LEN(addr)	(get_sa_len(addr))
133#else /* HAVE_STRUCT_SOCKADDR_STORAGE */
134#define SA_LEN(addr)	(sizeof (struct sockaddr))
135#endif /* HAVE_STRUCT_SOCKADDR_STORAGE */
136#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
137#endif /* SA_LEN */
138
139/*
140 * Get a list of all interfaces that are up and that we can open.
141 * Returns -1 on error, 0 otherwise.
142 * The list, as returned through "alldevsp", may be null if no interfaces
143 * could be opened.
144 */
145int
146pcap_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf,
147    int (*check_usable)(const char *), get_if_flags_func get_flags_func)
148{
149	struct ifaddrs *ifap, *ifa;
150	struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
151	size_t addr_size, broadaddr_size, dstaddr_size;
152	int ret = 0;
153	char *p, *q;
154
155	/*
156	 * Get the list of interface addresses.
157	 *
158	 * Note: this won't return information about interfaces
159	 * with no addresses, so, if a platform has interfaces
160	 * with no interfaces on which traffic can be captured,
161	 * we must check for those interfaces as well (see, for
162	 * example, what's done on Linux).
163	 *
164	 * LAN interfaces will probably have link-layer
165	 * addresses; I don't know whether all implementations
166	 * of "getifaddrs()" now, or in the future, will return
167	 * those.
168	 */
169	if (getifaddrs(&ifap) != 0) {
170		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
171		    errno, "getifaddrs");
172		return (-1);
173	}
174	for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
175		/*
176		 * If this entry has a colon followed by a number at
177		 * the end, we assume it's a logical interface.  Those
178		 * are just the way you assign multiple IP addresses to
179		 * a real interface on Linux, so an entry for a logical
180		 * interface should be treated like the entry for the
181		 * real interface; we do that by stripping off the ":"
182		 * and the number.
183		 *
184		 * XXX - should we do this only on Linux?
185		 */
186		p = strchr(ifa->ifa_name, ':');
187		if (p != NULL) {
188			/*
189			 * We have a ":"; is it followed by a number?
190			 */
191			q = p + 1;
192			while (PCAP_ISDIGIT(*q))
193				q++;
194			if (*q == '\0') {
195				/*
196				 * All digits after the ":" until the end.
197				 * Strip off the ":" and everything after
198				 * it.
199				 */
200			       *p = '\0';
201			}
202		}
203
204		/*
205		 * Can we capture on this device?
206		 */
207		if (!(*check_usable)(ifa->ifa_name)) {
208			/*
209			 * No.
210			 */
211			continue;
212		}
213
214		/*
215		 * "ifa_addr" was apparently null on at least one
216		 * interface on some system.  Therefore, we supply
217		 * the address and netmask only if "ifa_addr" is
218		 * non-null (if there's no address, there's obviously
219		 * no netmask).
220		 */
221		if (ifa->ifa_addr != NULL) {
222			addr = ifa->ifa_addr;
223			addr_size = SA_LEN(addr);
224			netmask = ifa->ifa_netmask;
225		} else {
226			addr = NULL;
227			addr_size = 0;
228			netmask = NULL;
229		}
230
231		/*
232		 * Note that, on some platforms, ifa_broadaddr and
233		 * ifa_dstaddr could be the same field (true on at
234		 * least some versions of *BSD and macOS), so we
235		 * can't just check whether the broadcast address
236		 * is null and add it if so and check whether the
237		 * destination address is null and add it if so.
238		 *
239		 * Therefore, we must also check the IFF_BROADCAST
240		 * flag, and only add a broadcast address if it's
241		 * set, and check the IFF_POINTTOPOINT flag, and
242		 * only add a destination address if it's set (as
243		 * per man page recommendations on some of those
244		 * platforms).
245		 */
246		if (ifa->ifa_flags & IFF_BROADCAST &&
247		    ifa->ifa_broadaddr != NULL) {
248			broadaddr = ifa->ifa_broadaddr;
249			broadaddr_size = SA_LEN(broadaddr);
250		} else {
251			broadaddr = NULL;
252			broadaddr_size = 0;
253		}
254		if (ifa->ifa_flags & IFF_POINTOPOINT &&
255		    ifa->ifa_dstaddr != NULL) {
256			dstaddr = ifa->ifa_dstaddr;
257			dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
258		} else {
259			dstaddr = NULL;
260			dstaddr_size = 0;
261		}
262
263		/*
264		 * Add information for this address to the list.
265		 */
266		if (add_addr_to_if(devlistp, ifa->ifa_name, ifa->ifa_flags,
267		    get_flags_func,
268		    addr, addr_size, netmask, addr_size,
269		    broadaddr, broadaddr_size, dstaddr, dstaddr_size,
270		    errbuf) < 0) {
271			ret = -1;
272			break;
273		}
274	}
275
276	freeifaddrs(ifap);
277
278	return (ret);
279}
280