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
108 static size_t
get_sa_len(struct sockaddr * addr)109 get_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 */
145 int
pcap_findalldevs_interfaces(pcap_if_list_t * devlistp,char * errbuf,int (* check_usable)(const char *),get_if_flags_func get_flags_func)146 pcap_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