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/param.h>
40 #include <sys/ioctl.h>
41 #include <sys/socket.h>
42 #ifdef HAVE_SYS_SOCKIO_H
43 #include <sys/sockio.h>
44 #endif
45 #include <sys/time.h> /* concession to AIX */
46
47 struct mbuf; /* Squelch compiler warnings on some platforms for */
48 struct rtentry; /* declarations in <net/if.h> */
49 #include <net/if.h>
50 #include <netinet/in.h>
51
52 #include <ctype.h>
53 #include <errno.h>
54 #include <memory.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59
60 #include "pcap-int.h"
61
62 #ifdef HAVE_OS_PROTO_H
63 #include "os-proto.h"
64 #endif
65
66 /*
67 * This is fun.
68 *
69 * In older BSD systems, socket addresses were fixed-length, and
70 * "sizeof (struct sockaddr)" gave the size of the structure.
71 * All addresses fit within a "struct sockaddr".
72 *
73 * In newer BSD systems, the socket address is variable-length, and
74 * there's an "sa_len" field giving the length of the structure;
75 * this allows socket addresses to be longer than 2 bytes of family
76 * and 14 bytes of data.
77 *
78 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
79 * variant of the old BSD scheme (with "struct sockaddr_storage" rather
80 * than "struct sockaddr"), and some use the new BSD scheme.
81 *
82 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
83 * macro that determines the size based on the address family. Other
84 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
85 * but not in the final version).
86 *
87 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
88 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
89 * address in an entry returned by SIOCGIFCONF.
90 */
91 #ifndef SA_LEN
92 #ifdef HAVE_SOCKADDR_SA_LEN
93 #define SA_LEN(addr) ((addr)->sa_len)
94 #else /* HAVE_SOCKADDR_SA_LEN */
95 #define SA_LEN(addr) (sizeof (struct sockaddr))
96 #endif /* HAVE_SOCKADDR_SA_LEN */
97 #endif /* SA_LEN */
98
99 /*
100 * This is also fun.
101 *
102 * There is no ioctl that returns the amount of space required for all
103 * the data that SIOCGIFCONF could return, and if a buffer is supplied
104 * that's not large enough for all the data SIOCGIFCONF could return,
105 * on at least some platforms it just returns the data that'd fit with
106 * no indication that there wasn't enough room for all the data, much
107 * less an indication of how much more room is required.
108 *
109 * The only way to ensure that we got all the data is to pass a buffer
110 * large enough that the amount of space in the buffer *not* filled in
111 * is greater than the largest possible entry.
112 *
113 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
114 * that no address is more than 255 bytes (on systems where the "sa_len"
115 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
116 * case, and addresses are unlikely to be bigger than that in any case).
117 */
118 #define MAX_SA_LEN 255
119
120 /*
121 * Get a list of all interfaces that are up and that we can open.
122 * Returns -1 on error, 0 otherwise.
123 * The list, as returned through "alldevsp", may be null if no interfaces
124 * were up and could be opened.
125 *
126 * This is the implementation used on platforms that have SIOCGIFCONF but
127 * don't have any other mechanism for getting a list of interfaces.
128 *
129 * XXX - or platforms that have other, better mechanisms but for which
130 * we don't yet have code to use that mechanism; I think there's a better
131 * way on Linux, for example, but if that better way is "getifaddrs()",
132 * we already have that.
133 */
134 int
pcap_findalldevs_interfaces(pcap_if_t ** alldevsp,char * errbuf,int (* check_usable)(const char *))135 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf,
136 int (*check_usable)(const char *))
137 {
138 pcap_if_t *devlist = NULL;
139 register int fd;
140 register struct ifreq *ifrp, *ifend, *ifnext;
141 size_t n;
142 struct ifconf ifc;
143 char *buf = NULL;
144 unsigned buf_size;
145 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
146 char *p, *q;
147 #endif
148 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
149 struct sockaddr *netmask, *broadaddr, *dstaddr;
150 size_t netmask_size, broadaddr_size, dstaddr_size;
151 int ret = 0;
152
153 /*
154 * Create a socket from which to fetch the list of interfaces.
155 */
156 fd = socket(AF_INET, SOCK_DGRAM, 0);
157 if (fd < 0) {
158 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
159 "socket: %s", pcap_strerror(errno));
160 return (-1);
161 }
162
163 /*
164 * Start with an 8K buffer, and keep growing the buffer until
165 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
166 * bytes left over in the buffer or we fail to get the
167 * interface list for some reason other than EINVAL (which is
168 * presumed here to mean "buffer is too small").
169 */
170 buf_size = 8192;
171 for (;;) {
172 buf = malloc(buf_size);
173 if (buf == NULL) {
174 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
175 "malloc: %s", pcap_strerror(errno));
176 (void)close(fd);
177 return (-1);
178 }
179
180 ifc.ifc_len = buf_size;
181 ifc.ifc_buf = buf;
182 memset(buf, 0, buf_size);
183 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
184 && errno != EINVAL) {
185 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
186 "SIOCGIFCONF: %s", pcap_strerror(errno));
187 (void)close(fd);
188 free(buf);
189 return (-1);
190 }
191 if (ifc.ifc_len < buf_size &&
192 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
193 break;
194 free(buf);
195 buf_size *= 2;
196 }
197
198 ifrp = (struct ifreq *)buf;
199 ifend = (struct ifreq *)(buf + ifc.ifc_len);
200
201 for (; ifrp < ifend; ifrp = ifnext) {
202 /*
203 * XXX - what if this isn't an IPv4 address? Can
204 * we still get the netmask, etc. with ioctls on
205 * an IPv4 socket?
206 *
207 * The answer is probably platform-dependent, and
208 * if the answer is "no" on more than one platform,
209 * the way you work around it is probably platform-
210 * dependent as well.
211 */
212 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
213 if (n < sizeof(*ifrp))
214 ifnext = ifrp + 1;
215 else
216 ifnext = (struct ifreq *)((char *)ifrp + n);
217
218 /*
219 * XXX - The 32-bit compatibility layer for Linux on IA-64
220 * is slightly broken. It correctly converts the structures
221 * to and from kernel land from 64 bit to 32 bit but
222 * doesn't update ifc.ifc_len, leaving it larger than the
223 * amount really used. This means we read off the end
224 * of the buffer and encounter an interface with an
225 * "empty" name. Since this is highly unlikely to ever
226 * occur in a valid case we can just finish looking for
227 * interfaces if we see an empty name.
228 */
229 if (!(*ifrp->ifr_name))
230 break;
231
232 /*
233 * Skip entries that begin with "dummy".
234 * XXX - what are these? Is this Linux-specific?
235 * Are there platforms on which we shouldn't do this?
236 */
237 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
238 continue;
239
240 /*
241 * Can we capture on this device?
242 */
243 if (!(*check_usable)(ifrp->ifr_name)) {
244 /*
245 * No.
246 */
247 continue;
248 }
249
250 /*
251 * Get the flags for this interface.
252 */
253 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
254 sizeof(ifrflags.ifr_name));
255 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
256 if (errno == ENXIO)
257 continue;
258 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
259 "SIOCGIFFLAGS: %.*s: %s",
260 (int)sizeof(ifrflags.ifr_name),
261 ifrflags.ifr_name,
262 pcap_strerror(errno));
263 ret = -1;
264 break;
265 }
266
267 /*
268 * Get the netmask for this address on this interface.
269 */
270 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
271 sizeof(ifrnetmask.ifr_name));
272 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
273 sizeof(ifrnetmask.ifr_addr));
274 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
275 if (errno == EADDRNOTAVAIL) {
276 /*
277 * Not available.
278 */
279 netmask = NULL;
280 netmask_size = 0;
281 } else {
282 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
283 "SIOCGIFNETMASK: %.*s: %s",
284 (int)sizeof(ifrnetmask.ifr_name),
285 ifrnetmask.ifr_name,
286 pcap_strerror(errno));
287 ret = -1;
288 break;
289 }
290 } else {
291 netmask = &ifrnetmask.ifr_addr;
292 netmask_size = SA_LEN(netmask);
293 }
294
295 /*
296 * Get the broadcast address for this address on this
297 * interface (if any).
298 */
299 if (ifrflags.ifr_flags & IFF_BROADCAST) {
300 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
301 sizeof(ifrbroadaddr.ifr_name));
302 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
303 sizeof(ifrbroadaddr.ifr_addr));
304 if (ioctl(fd, SIOCGIFBRDADDR,
305 (char *)&ifrbroadaddr) < 0) {
306 if (errno == EADDRNOTAVAIL) {
307 /*
308 * Not available.
309 */
310 broadaddr = NULL;
311 broadaddr_size = 0;
312 } else {
313 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
314 "SIOCGIFBRDADDR: %.*s: %s",
315 (int)sizeof(ifrbroadaddr.ifr_name),
316 ifrbroadaddr.ifr_name,
317 pcap_strerror(errno));
318 ret = -1;
319 break;
320 }
321 } else {
322 broadaddr = &ifrbroadaddr.ifr_broadaddr;
323 broadaddr_size = SA_LEN(broadaddr);
324 }
325 } else {
326 /*
327 * Not a broadcast interface, so no broadcast
328 * address.
329 */
330 broadaddr = NULL;
331 broadaddr_size = 0;
332 }
333
334 /*
335 * Get the destination address for this address on this
336 * interface (if any).
337 */
338 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
339 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
340 sizeof(ifrdstaddr.ifr_name));
341 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
342 sizeof(ifrdstaddr.ifr_addr));
343 if (ioctl(fd, SIOCGIFDSTADDR,
344 (char *)&ifrdstaddr) < 0) {
345 if (errno == EADDRNOTAVAIL) {
346 /*
347 * Not available.
348 */
349 dstaddr = NULL;
350 dstaddr_size = 0;
351 } else {
352 (void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
353 "SIOCGIFDSTADDR: %.*s: %s",
354 (int)sizeof(ifrdstaddr.ifr_name),
355 ifrdstaddr.ifr_name,
356 pcap_strerror(errno));
357 ret = -1;
358 break;
359 }
360 } else {
361 dstaddr = &ifrdstaddr.ifr_dstaddr;
362 dstaddr_size = SA_LEN(dstaddr);
363 }
364 } else {
365 /*
366 * Not a point-to-point interface, so no destination
367 * address.
368 */
369 dstaddr = NULL;
370 dstaddr_size = 0;
371 }
372
373 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
374 /*
375 * If this entry has a colon followed by a number at
376 * the end, it's a logical interface. Those are just
377 * the way you assign multiple IP addresses to a real
378 * interface, so an entry for a logical interface should
379 * be treated like the entry for the real interface;
380 * we do that by stripping off the ":" and the number.
381 */
382 p = strchr(ifrp->ifr_name, ':');
383 if (p != NULL) {
384 /*
385 * We have a ":"; is it followed by a number?
386 */
387 q = p + 1;
388 while (isdigit((unsigned char)*q))
389 q++;
390 if (*q == '\0') {
391 /*
392 * All digits after the ":" until the end.
393 * Strip off the ":" and everything after
394 * it.
395 */
396 *p = '\0';
397 }
398 }
399 #endif
400
401 /*
402 * Add information for this address to the list.
403 */
404 if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
405 if_flags_to_pcap_flags(ifrp->ifr_name, ifrflags.ifr_flags),
406 &ifrp->ifr_addr, SA_LEN(&ifrp->ifr_addr),
407 netmask, netmask_size, broadaddr, broadaddr_size,
408 dstaddr, dstaddr_size, errbuf) < 0) {
409 ret = -1;
410 break;
411 }
412 }
413 free(buf);
414 (void)close(fd);
415
416 if (ret == -1) {
417 /*
418 * We had an error; free the list we've been constructing.
419 */
420 if (devlist != NULL) {
421 pcap_freealldevs(devlist);
422 devlist = NULL;
423 }
424 }
425
426 *alldevsp = devlist;
427 return (ret);
428 }
429