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 #ifndef lint
36 static const char rcsid[] _U_ =
37 "@(#) $Header: /tcpdump/master/libpcap/fad-gifc.c,v 1.12 2008-08-06 07:34:09 guy Exp $ (LBL)";
38 #endif
39
40 #ifdef HAVE_CONFIG_H
41 #include "config.h"
42 #endif
43
44 #include <sys/param.h>
45 #include <sys/ioctl.h>
46 #include <sys/socket.h>
47 #ifdef HAVE_SYS_SOCKIO_H
48 #include <sys/sockio.h>
49 #endif
50 #include <sys/time.h> /* concession to AIX */
51
52 struct mbuf; /* Squelch compiler warnings on some platforms for */
53 struct rtentry; /* declarations in <net/if.h> */
54 #include <net/if.h>
55 #include <netinet/in.h>
56
57 #include <ctype.h>
58 #include <errno.h>
59 #include <memory.h>
60 #include <stdio.h>
61 #include <stdlib.h>
62 #include <string.h>
63 #include <unistd.h>
64
65 #include "pcap-int.h"
66
67 #ifdef HAVE_OS_PROTO_H
68 #include "os-proto.h"
69 #endif
70
71 /*
72 * This is fun.
73 *
74 * In older BSD systems, socket addresses were fixed-length, and
75 * "sizeof (struct sockaddr)" gave the size of the structure.
76 * All addresses fit within a "struct sockaddr".
77 *
78 * In newer BSD systems, the socket address is variable-length, and
79 * there's an "sa_len" field giving the length of the structure;
80 * this allows socket addresses to be longer than 2 bytes of family
81 * and 14 bytes of data.
82 *
83 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
84 * variant of the old BSD scheme (with "struct sockaddr_storage" rather
85 * than "struct sockaddr"), and some use the new BSD scheme.
86 *
87 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
88 * macro that determines the size based on the address family. Other
89 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
90 * but not in the final version).
91 *
92 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
93 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
94 * address in an entry returned by SIOCGIFCONF.
95 */
96 #ifndef SA_LEN
97 #ifdef HAVE_SOCKADDR_SA_LEN
98 #define SA_LEN(addr) ((addr)->sa_len)
99 #else /* HAVE_SOCKADDR_SA_LEN */
100 #define SA_LEN(addr) (sizeof (struct sockaddr))
101 #endif /* HAVE_SOCKADDR_SA_LEN */
102 #endif /* SA_LEN */
103
104 /*
105 * This is also fun.
106 *
107 * There is no ioctl that returns the amount of space required for all
108 * the data that SIOCGIFCONF could return, and if a buffer is supplied
109 * that's not large enough for all the data SIOCGIFCONF could return,
110 * on at least some platforms it just returns the data that'd fit with
111 * no indication that there wasn't enough room for all the data, much
112 * less an indication of how much more room is required.
113 *
114 * The only way to ensure that we got all the data is to pass a buffer
115 * large enough that the amount of space in the buffer *not* filled in
116 * is greater than the largest possible entry.
117 *
118 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
119 * that no address is more than 255 bytes (on systems where the "sa_len"
120 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
121 * case, and addresses are unlikely to be bigger than that in any case).
122 */
123 #define MAX_SA_LEN 255
124
125 /*
126 * Get a list of all interfaces that are up and that we can open.
127 * Returns -1 on error, 0 otherwise.
128 * The list, as returned through "alldevsp", may be null if no interfaces
129 * were up and could be opened.
130 *
131 * This is the implementation used on platforms that have SIOCGIFCONF but
132 * don't have any other mechanism for getting a list of interfaces.
133 *
134 * XXX - or platforms that have other, better mechanisms but for which
135 * we don't yet have code to use that mechanism; I think there's a better
136 * way on Linux, for example, but if that better way is "getifaddrs()",
137 * we already have that.
138 */
139 int
pcap_findalldevs_interfaces(pcap_if_t ** alldevsp,char * errbuf)140 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf)
141 {
142 pcap_if_t *devlist = NULL;
143 register int fd;
144 register struct ifreq *ifrp, *ifend, *ifnext;
145 int n;
146 struct ifconf ifc;
147 char *buf = NULL;
148 unsigned buf_size;
149 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
150 char *p, *q;
151 #endif
152 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
153 struct sockaddr *netmask, *broadaddr, *dstaddr;
154 size_t netmask_size, broadaddr_size, dstaddr_size;
155 int ret = 0;
156
157 /*
158 * Create a socket from which to fetch the list of interfaces.
159 */
160 fd = socket(AF_INET, SOCK_DGRAM, 0);
161 if (fd < 0) {
162 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
163 "socket: %s", pcap_strerror(errno));
164 return (-1);
165 }
166
167 /*
168 * Start with an 8K buffer, and keep growing the buffer until
169 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
170 * bytes left over in the buffer or we fail to get the
171 * interface list for some reason other than EINVAL (which is
172 * presumed here to mean "buffer is too small").
173 */
174 buf_size = 8192;
175 for (;;) {
176 buf = malloc(buf_size);
177 if (buf == NULL) {
178 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
179 "malloc: %s", pcap_strerror(errno));
180 (void)close(fd);
181 return (-1);
182 }
183
184 ifc.ifc_len = buf_size;
185 ifc.ifc_buf = buf;
186 memset(buf, 0, buf_size);
187 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
188 && errno != EINVAL) {
189 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
190 "SIOCGIFCONF: %s", pcap_strerror(errno));
191 (void)close(fd);
192 free(buf);
193 return (-1);
194 }
195 if (ifc.ifc_len < buf_size &&
196 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
197 break;
198 free(buf);
199 buf_size *= 2;
200 }
201
202 ifrp = (struct ifreq *)buf;
203 ifend = (struct ifreq *)(buf + ifc.ifc_len);
204
205 for (; ifrp < ifend; ifrp = ifnext) {
206 /*
207 * XXX - what if this isn't an IPv4 address? Can
208 * we still get the netmask, etc. with ioctls on
209 * an IPv4 socket?
210 *
211 * The answer is probably platform-dependent, and
212 * if the answer is "no" on more than one platform,
213 * the way you work around it is probably platform-
214 * dependent as well.
215 */
216 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
217 if (n < sizeof(*ifrp))
218 ifnext = ifrp + 1;
219 else
220 ifnext = (struct ifreq *)((char *)ifrp + n);
221
222 /*
223 * XXX - The 32-bit compatibility layer for Linux on IA-64
224 * is slightly broken. It correctly converts the structures
225 * to and from kernel land from 64 bit to 32 bit but
226 * doesn't update ifc.ifc_len, leaving it larger than the
227 * amount really used. This means we read off the end
228 * of the buffer and encounter an interface with an
229 * "empty" name. Since this is highly unlikely to ever
230 * occur in a valid case we can just finish looking for
231 * interfaces if we see an empty name.
232 */
233 if (!(*ifrp->ifr_name))
234 break;
235
236 /*
237 * Skip entries that begin with "dummy".
238 * XXX - what are these? Is this Linux-specific?
239 * Are there platforms on which we shouldn't do this?
240 */
241 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
242 continue;
243
244 /*
245 * Get the flags for this interface, and skip it if it's
246 * not up.
247 */
248 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
249 sizeof(ifrflags.ifr_name));
250 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
251 if (errno == ENXIO)
252 continue;
253 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
254 "SIOCGIFFLAGS: %.*s: %s",
255 (int)sizeof(ifrflags.ifr_name),
256 ifrflags.ifr_name,
257 pcap_strerror(errno));
258 ret = -1;
259 break;
260 }
261 if (!(ifrflags.ifr_flags & IFF_UP))
262 continue;
263
264 /*
265 * Get the netmask for this address on this interface.
266 */
267 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
268 sizeof(ifrnetmask.ifr_name));
269 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
270 sizeof(ifrnetmask.ifr_addr));
271 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
272 if (errno == EADDRNOTAVAIL) {
273 /*
274 * Not available.
275 */
276 netmask = NULL;
277 netmask_size = 0;
278 } else {
279 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
280 "SIOCGIFNETMASK: %.*s: %s",
281 (int)sizeof(ifrnetmask.ifr_name),
282 ifrnetmask.ifr_name,
283 pcap_strerror(errno));
284 ret = -1;
285 break;
286 }
287 } else {
288 netmask = &ifrnetmask.ifr_addr;
289 netmask_size = SA_LEN(netmask);
290 }
291
292 /*
293 * Get the broadcast address for this address on this
294 * interface (if any).
295 */
296 if (ifrflags.ifr_flags & IFF_BROADCAST) {
297 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
298 sizeof(ifrbroadaddr.ifr_name));
299 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
300 sizeof(ifrbroadaddr.ifr_addr));
301 if (ioctl(fd, SIOCGIFBRDADDR,
302 (char *)&ifrbroadaddr) < 0) {
303 if (errno == EADDRNOTAVAIL) {
304 /*
305 * Not available.
306 */
307 broadaddr = NULL;
308 broadaddr_size = 0;
309 } else {
310 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
311 "SIOCGIFBRDADDR: %.*s: %s",
312 (int)sizeof(ifrbroadaddr.ifr_name),
313 ifrbroadaddr.ifr_name,
314 pcap_strerror(errno));
315 ret = -1;
316 break;
317 }
318 } else {
319 broadaddr = &ifrbroadaddr.ifr_broadaddr;
320 broadaddr_size = SA_LEN(broadaddr);
321 }
322 } else {
323 /*
324 * Not a broadcast interface, so no broadcast
325 * address.
326 */
327 broadaddr = NULL;
328 broadaddr_size = 0;
329 }
330
331 /*
332 * Get the destination address for this address on this
333 * interface (if any).
334 */
335 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
336 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
337 sizeof(ifrdstaddr.ifr_name));
338 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
339 sizeof(ifrdstaddr.ifr_addr));
340 if (ioctl(fd, SIOCGIFDSTADDR,
341 (char *)&ifrdstaddr) < 0) {
342 if (errno == EADDRNOTAVAIL) {
343 /*
344 * Not available.
345 */
346 dstaddr = NULL;
347 dstaddr_size = 0;
348 } else {
349 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
350 "SIOCGIFDSTADDR: %.*s: %s",
351 (int)sizeof(ifrdstaddr.ifr_name),
352 ifrdstaddr.ifr_name,
353 pcap_strerror(errno));
354 ret = -1;
355 break;
356 }
357 } else {
358 dstaddr = &ifrdstaddr.ifr_dstaddr;
359 dstaddr_size = SA_LEN(dstaddr);
360 }
361 } else {
362 /*
363 * Not a point-to-point interface, so no destination
364 * address.
365 */
366 dstaddr = NULL;
367 dstaddr_size = 0;
368 }
369
370 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
371 /*
372 * If this entry has a colon followed by a number at
373 * the end, it's a logical interface. Those are just
374 * the way you assign multiple IP addresses to a real
375 * interface, so an entry for a logical interface should
376 * be treated like the entry for the real interface;
377 * we do that by stripping off the ":" and the number.
378 */
379 p = strchr(ifrp->ifr_name, ':');
380 if (p != NULL) {
381 /*
382 * We have a ":"; is it followed by a number?
383 */
384 q = p + 1;
385 while (isdigit((unsigned char)*q))
386 q++;
387 if (*q == '\0') {
388 /*
389 * All digits after the ":" until the end.
390 * Strip off the ":" and everything after
391 * it.
392 */
393 *p = '\0';
394 }
395 }
396 #endif
397
398 /*
399 * Add information for this address to the list.
400 */
401 if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
402 ifrflags.ifr_flags, &ifrp->ifr_addr,
403 SA_LEN(&ifrp->ifr_addr), netmask, netmask_size,
404 broadaddr, broadaddr_size, dstaddr, dstaddr_size,
405 errbuf) < 0) {
406 ret = -1;
407 break;
408 }
409 }
410 free(buf);
411 (void)close(fd);
412
413 if (ret == -1) {
414 /*
415 * We had an error; free the list we've been constructing.
416 */
417 if (devlist != NULL) {
418 pcap_freealldevs(devlist);
419 devlist = NULL;
420 }
421 }
422
423 *alldevsp = devlist;
424 return (ret);
425 }
426