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_SOCKADDR_SA_LEN
106 #define SA_LEN(addr) ((addr)->sa_len)
107 #else /* HAVE_SOCKADDR_SA_LEN */
108 #ifdef HAVE_SOCKADDR_STORAGE
109 static size_t
get_sa_len(struct sockaddr * addr)110 get_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_SOCKADDR_STORAGE */
135 #define SA_LEN(addr) (sizeof (struct sockaddr))
136 #endif /* HAVE_SOCKADDR_STORAGE */
137 #endif /* HAVE_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 */
146 int
pcap_findalldevs_interfaces(pcap_if_t ** alldevsp,char * errbuf)147 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf)
148 {
149 pcap_if_t *devlist = NULL;
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 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
172 "getifaddrs: %s", pcap_strerror(errno));
173 return (-1);
174 }
175 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
176 /*
177 * "ifa_addr" was apparently null on at least one
178 * interface on some system. Therefore, we supply
179 * the address and netmask only if "ifa_addr" is
180 * non-null (if there's no address, there's obviously
181 * no netmask).
182 */
183 if (ifa->ifa_addr != NULL) {
184 addr = ifa->ifa_addr;
185 addr_size = SA_LEN(addr);
186 netmask = ifa->ifa_netmask;
187 } else {
188 addr = NULL;
189 addr_size = 0;
190 netmask = NULL;
191 }
192
193 /*
194 * Note that, on some platforms, ifa_broadaddr and
195 * ifa_dstaddr could be the same field (true on at
196 * least some versions of *BSD and OS X), so we
197 * can't just check whether the broadcast address
198 * is null and add it if so and check whether the
199 * destination address is null and add it if so.
200 *
201 * Therefore, we must also check the IFF_BROADCAST
202 * flag, and only add a broadcast address if it's
203 * set, and check the IFF_POINTTOPOINT flag, and
204 * only add a destination address if it's set (as
205 * per man page recommendations on some of those
206 * platforms).
207 */
208 if (ifa->ifa_flags & IFF_BROADCAST &&
209 ifa->ifa_broadaddr != NULL) {
210 broadaddr = ifa->ifa_broadaddr;
211 broadaddr_size = SA_LEN(broadaddr);
212 } else {
213 broadaddr = NULL;
214 broadaddr_size = 0;
215 }
216 if (ifa->ifa_flags & IFF_POINTOPOINT &&
217 ifa->ifa_dstaddr != NULL) {
218 dstaddr = ifa->ifa_dstaddr;
219 dstaddr_size = SA_LEN(ifa->ifa_dstaddr);
220 } else {
221 dstaddr = NULL;
222 dstaddr_size = 0;
223 }
224
225 /*
226 * If this entry has a colon followed by a number at
227 * the end, we assume it's a logical interface. Those
228 * are just the way you assign multiple IP addresses to
229 * a real interface on Linux, so an entry for a logical
230 * interface should be treated like the entry for the
231 * real interface; we do that by stripping off the ":"
232 * and the number.
233 *
234 * XXX - should we do this only on Linux?
235 */
236 p = strchr(ifa->ifa_name, ':');
237 if (p != NULL) {
238 /*
239 * We have a ":"; is it followed by a number?
240 */
241 q = p + 1;
242 while (isdigit((unsigned char)*q))
243 q++;
244 if (*q == '\0') {
245 /*
246 * All digits after the ":" until the end.
247 * Strip off the ":" and everything after
248 * it.
249 */
250 *p = '\0';
251 }
252 }
253
254 /*
255 * Add information for this address to the list.
256 */
257 if (add_addr_to_iflist(&devlist, ifa->ifa_name,
258 ifa->ifa_flags, addr, addr_size, netmask, addr_size,
259 broadaddr, broadaddr_size, dstaddr, dstaddr_size,
260 errbuf) < 0) {
261 ret = -1;
262 break;
263 }
264 }
265
266 freeifaddrs(ifap);
267
268 if (ret == -1) {
269 /*
270 * We had an error; free the list we've been constructing.
271 */
272 if (devlist != NULL) {
273 pcap_freealldevs(devlist);
274 devlist = NULL;
275 }
276 }
277
278 *alldevsp = devlist;
279 return (ret);
280 }
281