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 <ctype.h>
46#include <errno.h>
47#include <stdio.h>
48#include <stdlib.h>
49#include <string.h>
50#include <ifaddrs.h>
51
52#include "pcap-int.h"
53
54#ifdef HAVE_OS_PROTO_H
55#include "os-proto.h"
56#endif
57
58/*
59 * We don't do this on Solaris 11 and later, as it appears there aren't
60 * any AF_PACKET addresses on interfaces, so we don't need this, and
61 * we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>,
62 * and their definitions of some data structures collide.
63 */
64#if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
65# ifdef HAVE_NETPACKET_PACKET_H
66/* Linux distributions with newer glibc */
67#  include <netpacket/packet.h>
68# else /* HAVE_NETPACKET_PACKET_H */
69/* LynxOS, Linux distributions with older glibc */
70# ifdef __Lynx__
71/* LynxOS */
72#  include <netpacket/if_packet.h>
73# else /* __Lynx__ */
74/* Linux */
75#  include <linux/types.h>
76#  include <linux/if_packet.h>
77# endif /* __Lynx__ */
78# endif /* HAVE_NETPACKET_PACKET_H */
79#endif /* (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET) */
80
81/*
82 * This is fun.
83 *
84 * In older BSD systems, socket addresses were fixed-length, and
85 * "sizeof (struct sockaddr)" gave the size of the structure.
86 * All addresses fit within a "struct sockaddr".
87 *
88 * In newer BSD systems, the socket address is variable-length, and
89 * there's an "sa_len" field giving the length of the structure;
90 * this allows socket addresses to be longer than 2 bytes of family
91 * and 14 bytes of data.
92 *
93 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
94 * variant of the old BSD scheme (with "struct sockaddr_storage" rather
95 * than "struct sockaddr"), and some use the new BSD scheme.
96 *
97 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
98 * macro that determines the size based on the address family.  Other
99 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
100 * but not in the final version).  On the latter systems, we explicitly
101 * check the AF_ type to determine the length; we assume that on
102 * all those systems we have "struct sockaddr_storage".
103 */
104#ifndef SA_LEN
105#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
106#define SA_LEN(addr)	((addr)->sa_len)
107#else /* HAVE_STRUCT_SOCKADDR_SA_LEN */
108#ifdef HAVE_STRUCT_SOCKADDR_STORAGE
109static size_t
110get_sa_len(struct sockaddr *addr)
111{
112	switch (addr->sa_family) {
113
114#ifdef AF_INET
115	case AF_INET:
116		return (sizeof (struct sockaddr_in));
117#endif
118
119#ifdef AF_INET6
120	case AF_INET6:
121		return (sizeof (struct sockaddr_in6));
122#endif
123
124#if (defined(linux) || defined(__Lynx__)) && defined(AF_PACKET)
125	case AF_PACKET:
126		return (sizeof (struct sockaddr_ll));
127#endif
128
129	default:
130		return (sizeof (struct sockaddr));
131	}
132}
133#define SA_LEN(addr)	(get_sa_len(addr))
134#else /* HAVE_STRUCT_SOCKADDR_STORAGE */
135#define SA_LEN(addr)	(sizeof (struct sockaddr))
136#endif /* HAVE_STRUCT_SOCKADDR_STORAGE */
137#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
138#endif /* SA_LEN */
139
140/*
141 * Get a list of all interfaces that are up and that we can open.
142 * Returns -1 on error, 0 otherwise.
143 * The list, as returned through "alldevsp", may be null if no interfaces
144 * could be opened.
145 */
146int
147pcap_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf,
148    int (*check_usable)(const char *), get_if_flags_func get_flags_func)
149{
150	struct ifaddrs *ifap, *ifa;
151	struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
152	size_t addr_size, broadaddr_size, dstaddr_size;
153	int ret = 0;
154	char *p, *q;
155
156	/*
157	 * Get the list of interface addresses.
158	 *
159	 * Note: this won't return information about interfaces
160	 * with no addresses, so, if a platform has interfaces
161	 * with no interfaces on which traffic can be captured,
162	 * we must check for those interfaces as well (see, for
163	 * example, what's done on Linux).
164	 *
165	 * LAN interfaces will probably have link-layer
166	 * addresses; I don't know whether all implementations
167	 * of "getifaddrs()" now, or in the future, will return
168	 * those.
169	 */
170	if (getifaddrs(&ifap) != 0) {
171		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
172		    errno, "getifaddrs");
173		return (-1);
174	}
175	for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
176		/*
177		 * If this entry has a colon followed by a number at
178		 * the end, we assume it's a logical interface.  Those
179		 * are just the way you assign multiple IP addresses to
180		 * a real interface on Linux, so an entry for a logical
181		 * interface should be treated like the entry for the
182		 * real interface; we do that by stripping off the ":"
183		 * and the number.
184		 *
185		 * XXX - should we do this only on Linux?
186		 */
187		p = strchr(ifa->ifa_name, ':');
188		if (p != NULL) {
189			/*
190			 * We have a ":"; is it followed by a number?
191			 */
192			q = p + 1;
193			while (isdigit((unsigned char)*q))
194				q++;
195			if (*q == '\0') {
196				/*
197				 * All digits after the ":" until the end.
198				 * Strip off the ":" and everything after
199				 * it.
200				 */
201			       *p = '\0';
202			}
203		}
204
205		/*
206		 * Can we capture on this device?
207		 */
208		if (!(*check_usable)(ifa->ifa_name)) {
209			/*
210			 * No.
211			 */
212			continue;
213		}
214
215		/*
216		 * "ifa_addr" was apparently null on at least one
217		 * interface on some system.  Therefore, we supply
218		 * the address and netmask only if "ifa_addr" is
219		 * non-null (if there's no address, there's obviously
220		 * no netmask).
221		 */
222		if (ifa->ifa_addr != NULL) {
223			addr = ifa->ifa_addr;
224			addr_size = SA_LEN(addr);
225			netmask = ifa->ifa_netmask;
226		} else {
227			addr = NULL;
228			addr_size = 0;
229			netmask = NULL;
230		}
231
232		/*
233		 * Note that, on some platforms, ifa_broadaddr and
234		 * ifa_dstaddr could be the same field (true on at
235		 * least some versions of *BSD and macOS), so we
236		 * can't just check whether the broadcast address
237		 * is null and add it if so and check whether the
238		 * destination address is null and add it if so.
239		 *
240		 * Therefore, we must also check the IFF_BROADCAST
241		 * flag, and only add a broadcast address if it's
242		 * set, and check the IFF_POINTTOPOINT flag, and
243		 * only add a destination address if it's set (as
244		 * per man page recommendations on some of those
245		 * platforms).
246		 */
247		if (ifa->ifa_flags & IFF_BROADCAST &&
248		    ifa->ifa_broadaddr != NULL) {
249			broadaddr = ifa->ifa_broadaddr;
250			broadaddr_size = SA_LEN(broadaddr);
251		} else {
252			broadaddr = NULL;
253			broadaddr_size = 0;
254		}
255		if (ifa->ifa_flags & IFF_POINTOPOINT &&
256		    ifa->ifa_dstaddr != NULL) {
257			dstaddr = ifa->ifa_dstaddr;
258			dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
259		} else {
260			dstaddr = NULL;
261			dstaddr_size = 0;
262		}
263
264		/*
265		 * Add information for this address to the list.
266		 */
267		if (add_addr_to_if(devlistp, ifa->ifa_name, ifa->ifa_flags,
268		    get_flags_func,
269		    addr, addr_size, netmask, addr_size,
270		    broadaddr, broadaddr_size, dstaddr, dstaddr_size,
271		    errbuf) < 0) {
272			ret = -1;
273			break;
274		}
275	}
276
277	freeifaddrs(ifap);
278
279	return (ret);
280}
281