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 1.8.2.2 2005/06/29 06:43:31 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/file.h>
46 #include <sys/ioctl.h>
47 #include <sys/socket.h>
48 #ifdef HAVE_SYS_SOCKIO_H
49 #include <sys/sockio.h>
50 #endif
51 #include <sys/time.h> /* concession to AIX */
52
53 struct mbuf; /* Squelch compiler warnings on some platforms for */
54 struct rtentry; /* declarations in <net/if.h> */
55 #include <net/if.h>
56 #include <netinet/in.h>
57
58 #include <ctype.h>
59 #include <errno.h>
60 #include <memory.h>
61 #include <stdio.h>
62 #include <stdlib.h>
63 #include <string.h>
64 #include <unistd.h>
65
66 #include "pcap-int.h"
67
68 #ifdef HAVE_OS_PROTO_H
69 #include "os-proto.h"
70 #endif
71
72 /*
73 * This is fun.
74 *
75 * In older BSD systems, socket addresses were fixed-length, and
76 * "sizeof (struct sockaddr)" gave the size of the structure.
77 * All addresses fit within a "struct sockaddr".
78 *
79 * In newer BSD systems, the socket address is variable-length, and
80 * there's an "sa_len" field giving the length of the structure;
81 * this allows socket addresses to be longer than 2 bytes of family
82 * and 14 bytes of data.
83 *
84 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
85 * variant of the old BSD scheme (with "struct sockaddr_storage" rather
86 * than "struct sockaddr"), and some use the new BSD scheme.
87 *
88 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
89 * macro that determines the size based on the address family. Other
90 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
91 * but not in the final version).
92 *
93 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
94 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
95 * address in an entry returned by SIOCGIFCONF.
96 */
97 #ifndef SA_LEN
98 #ifdef HAVE_SOCKADDR_SA_LEN
99 #define SA_LEN(addr) ((addr)->sa_len)
100 #else /* HAVE_SOCKADDR_SA_LEN */
101 #define SA_LEN(addr) (sizeof (struct sockaddr))
102 #endif /* HAVE_SOCKADDR_SA_LEN */
103 #endif /* SA_LEN */
104
105 /*
106 * This is also fun.
107 *
108 * There is no ioctl that returns the amount of space required for all
109 * the data that SIOCGIFCONF could return, and if a buffer is supplied
110 * that's not large enough for all the data SIOCGIFCONF could return,
111 * on at least some platforms it just returns the data that'd fit with
112 * no indication that there wasn't enough room for all the data, much
113 * less an indication of how much more room is required.
114 *
115 * The only way to ensure that we got all the data is to pass a buffer
116 * large enough that the amount of space in the buffer *not* filled in
117 * is greater than the largest possible entry.
118 *
119 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
120 * that no address is more than 255 bytes (on systems where the "sa_len"
121 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
122 * case, and addresses are unlikely to be bigger than that in any case).
123 */
124 #define MAX_SA_LEN 255
125
126 #ifdef HAVE_PROC_NET_DEV
127 /*
128 * Get from "/proc/net/dev" all interfaces listed there; if they're
129 * already in the list of interfaces we have, that won't add another
130 * instance, but if they're not, that'll add them.
131 *
132 * We don't bother getting any addresses for them; it appears you can't
133 * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
134 * although some other types of addresses can be fetched with SIOCGIFADDR,
135 * we don't bother with them for now.
136 *
137 * We also don't fail if we couldn't open "/proc/net/dev"; we just leave
138 * the list of interfaces as is.
139 */
140 static int
scan_proc_net_dev(pcap_if_t ** devlistp,int fd,char * errbuf)141 scan_proc_net_dev(pcap_if_t **devlistp, int fd, char *errbuf)
142 {
143 FILE *proc_net_f;
144 char linebuf[512];
145 int linenum;
146 unsigned char *p;
147 char name[512]; /* XXX - pick a size */
148 char *q, *saveq;
149 struct ifreq ifrflags;
150 int ret = 0;
151
152 proc_net_f = fopen("/proc/net/dev", "r");
153 if (proc_net_f == NULL)
154 return (0);
155
156 for (linenum = 1;
157 fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
158 /*
159 * Skip the first two lines - they're headers.
160 */
161 if (linenum <= 2)
162 continue;
163
164 p = &linebuf[0];
165
166 /*
167 * Skip leading white space.
168 */
169 while (*p != '\0' && isspace(*p))
170 p++;
171 if (*p == '\0' || *p == '\n')
172 continue; /* blank line */
173
174 /*
175 * Get the interface name.
176 */
177 q = &name[0];
178 while (*p != '\0' && !isspace(*p)) {
179 if (*p == ':') {
180 /*
181 * This could be the separator between a
182 * name and an alias number, or it could be
183 * the separator between a name with no
184 * alias number and the next field.
185 *
186 * If there's a colon after digits, it
187 * separates the name and the alias number,
188 * otherwise it separates the name and the
189 * next field.
190 */
191 saveq = q;
192 while (isdigit(*p))
193 *q++ = *p++;
194 if (*p != ':') {
195 /*
196 * That was the next field,
197 * not the alias number.
198 */
199 q = saveq;
200 }
201 break;
202 } else
203 *q++ = *p++;
204 }
205 *q = '\0';
206
207 /*
208 * Get the flags for this interface, and skip it if
209 * it's not up.
210 */
211 strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
212 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
213 if (errno == ENXIO)
214 continue;
215 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
216 "SIOCGIFFLAGS: %.*s: %s",
217 (int)sizeof(ifrflags.ifr_name),
218 ifrflags.ifr_name,
219 pcap_strerror(errno));
220 ret = -1;
221 break;
222 }
223 if (!(ifrflags.ifr_flags & IFF_UP))
224 continue;
225
226 /*
227 * Add an entry for this interface, with no addresses.
228 */
229 if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
230 errbuf) == -1) {
231 /*
232 * Failure.
233 */
234 ret = -1;
235 break;
236 }
237 }
238 if (ret != -1) {
239 /*
240 * Well, we didn't fail for any other reason; did we
241 * fail due to an error reading the file?
242 */
243 if (ferror(proc_net_f)) {
244 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
245 "Error reading /proc/net/dev: %s",
246 pcap_strerror(errno));
247 ret = -1;
248 }
249 }
250
251 (void)fclose(proc_net_f);
252 return (ret);
253 }
254 #endif /* HAVE_PROC_NET_DEV */
255
256 /*
257 * Get a list of all interfaces that are up and that we can open.
258 * Returns -1 on error, 0 otherwise.
259 * The list, as returned through "alldevsp", may be null if no interfaces
260 * were up and could be opened.
261 *
262 * This is the implementation used on platforms that have SIOCGIFCONF but
263 * don't have any other mechanism for getting a list of interfaces.
264 *
265 * XXX - or platforms that have other, better mechanisms but for which
266 * we don't yet have code to use that mechanism; I think there's a better
267 * way on Linux, for example.
268 */
269 int
pcap_findalldevs(pcap_if_t ** alldevsp,char * errbuf)270 pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
271 {
272 pcap_if_t *devlist = NULL;
273 register int fd;
274 register struct ifreq *ifrp, *ifend, *ifnext;
275 int n;
276 struct ifconf ifc;
277 char *buf = NULL;
278 unsigned buf_size;
279 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
280 char *p, *q;
281 #endif
282 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
283 struct sockaddr *netmask, *broadaddr, *dstaddr;
284 size_t netmask_size, broadaddr_size, dstaddr_size;
285 int ret = 0;
286
287 /*
288 * Create a socket from which to fetch the list of interfaces.
289 */
290 fd = socket(AF_INET, SOCK_DGRAM, 0);
291 if (fd < 0) {
292 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
293 "socket: %s", pcap_strerror(errno));
294 return (-1);
295 }
296
297 /*
298 * Start with an 8K buffer, and keep growing the buffer until
299 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
300 * bytes left over in the buffer or we fail to get the
301 * interface list for some reason other than EINVAL (which is
302 * presumed here to mean "buffer is too small").
303 */
304 buf_size = 8192;
305 for (;;) {
306 buf = malloc(buf_size);
307 if (buf == NULL) {
308 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
309 "malloc: %s", pcap_strerror(errno));
310 (void)close(fd);
311 return (-1);
312 }
313
314 ifc.ifc_len = buf_size;
315 ifc.ifc_buf = buf;
316 memset(buf, 0, buf_size);
317 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
318 && errno != EINVAL) {
319 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
320 "SIOCGIFCONF: %s", pcap_strerror(errno));
321 (void)close(fd);
322 free(buf);
323 return (-1);
324 }
325 if (ifc.ifc_len < buf_size &&
326 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
327 break;
328 free(buf);
329 buf_size *= 2;
330 }
331
332 ifrp = (struct ifreq *)buf;
333 ifend = (struct ifreq *)(buf + ifc.ifc_len);
334
335 for (; ifrp < ifend; ifrp = ifnext) {
336 /*
337 * XXX - what if this isn't an IPv4 address? Can
338 * we still get the netmask, etc. with ioctls on
339 * an IPv4 socket?
340 *
341 * The answer is probably platform-dependent, and
342 * if the answer is "no" on more than one platform,
343 * the way you work around it is probably platform-
344 * dependent as well.
345 */
346 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
347 if (n < sizeof(*ifrp))
348 ifnext = ifrp + 1;
349 else
350 ifnext = (struct ifreq *)((char *)ifrp + n);
351
352 /*
353 * XXX - The 32-bit compatibility layer for Linux on IA-64
354 * is slightly broken. It correctly converts the structures
355 * to and from kernel land from 64 bit to 32 bit but
356 * doesn't update ifc.ifc_len, leaving it larger than the
357 * amount really used. This means we read off the end
358 * of the buffer and encounter an interface with an
359 * "empty" name. Since this is highly unlikely to ever
360 * occur in a valid case we can just finish looking for
361 * interfaces if we see an empty name.
362 */
363 if (!(*ifrp->ifr_name))
364 break;
365
366 /*
367 * Skip entries that begin with "dummy".
368 * XXX - what are these? Is this Linux-specific?
369 * Are there platforms on which we shouldn't do this?
370 */
371 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
372 continue;
373
374 /*
375 * Get the flags for this interface, and skip it if it's
376 * not up.
377 */
378 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
379 sizeof(ifrflags.ifr_name));
380 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
381 if (errno == ENXIO)
382 continue;
383 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
384 "SIOCGIFFLAGS: %.*s: %s",
385 (int)sizeof(ifrflags.ifr_name),
386 ifrflags.ifr_name,
387 pcap_strerror(errno));
388 ret = -1;
389 break;
390 }
391 if (!(ifrflags.ifr_flags & IFF_UP))
392 continue;
393
394 /*
395 * Get the netmask for this address on this interface.
396 */
397 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
398 sizeof(ifrnetmask.ifr_name));
399 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
400 sizeof(ifrnetmask.ifr_addr));
401 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
402 if (errno == EADDRNOTAVAIL) {
403 /*
404 * Not available.
405 */
406 netmask = NULL;
407 netmask_size = 0;
408 } else {
409 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
410 "SIOCGIFNETMASK: %.*s: %s",
411 (int)sizeof(ifrnetmask.ifr_name),
412 ifrnetmask.ifr_name,
413 pcap_strerror(errno));
414 ret = -1;
415 break;
416 }
417 } else {
418 netmask = &ifrnetmask.ifr_addr;
419 netmask_size = SA_LEN(netmask);
420 }
421
422 /*
423 * Get the broadcast address for this address on this
424 * interface (if any).
425 */
426 if (ifrflags.ifr_flags & IFF_BROADCAST) {
427 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
428 sizeof(ifrbroadaddr.ifr_name));
429 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
430 sizeof(ifrbroadaddr.ifr_addr));
431 if (ioctl(fd, SIOCGIFBRDADDR,
432 (char *)&ifrbroadaddr) < 0) {
433 if (errno == EADDRNOTAVAIL) {
434 /*
435 * Not available.
436 */
437 broadaddr = NULL;
438 broadaddr_size = 0;
439 } else {
440 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
441 "SIOCGIFBRDADDR: %.*s: %s",
442 (int)sizeof(ifrbroadaddr.ifr_name),
443 ifrbroadaddr.ifr_name,
444 pcap_strerror(errno));
445 ret = -1;
446 break;
447 }
448 } else {
449 broadaddr = &ifrbroadaddr.ifr_broadaddr;
450 broadaddr_size = SA_LEN(broadaddr);
451 }
452 } else {
453 /*
454 * Not a broadcast interface, so no broadcast
455 * address.
456 */
457 broadaddr = NULL;
458 broadaddr_size = 0;
459 }
460
461 /*
462 * Get the destination address for this address on this
463 * interface (if any).
464 */
465 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
466 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
467 sizeof(ifrdstaddr.ifr_name));
468 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
469 sizeof(ifrdstaddr.ifr_addr));
470 if (ioctl(fd, SIOCGIFDSTADDR,
471 (char *)&ifrdstaddr) < 0) {
472 if (errno == EADDRNOTAVAIL) {
473 /*
474 * Not available.
475 */
476 dstaddr = NULL;
477 dstaddr_size = 0;
478 } else {
479 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
480 "SIOCGIFDSTADDR: %.*s: %s",
481 (int)sizeof(ifrdstaddr.ifr_name),
482 ifrdstaddr.ifr_name,
483 pcap_strerror(errno));
484 ret = -1;
485 break;
486 }
487 } else {
488 dstaddr = &ifrdstaddr.ifr_dstaddr;
489 dstaddr_size = SA_LEN(dstaddr);
490 }
491 } else {
492 /*
493 * Not a point-to-point interface, so no destination
494 * address.
495 */
496 dstaddr = NULL;
497 dstaddr_size = 0;
498 }
499
500 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
501 /*
502 * If this entry has a colon followed by a number at
503 * the end, it's a logical interface. Those are just
504 * the way you assign multiple IP addresses to a real
505 * interface, so an entry for a logical interface should
506 * be treated like the entry for the real interface;
507 * we do that by stripping off the ":" and the number.
508 */
509 p = strchr(ifrp->ifr_name, ':');
510 if (p != NULL) {
511 /*
512 * We have a ":"; is it followed by a number?
513 */
514 q = p + 1;
515 while (isdigit((unsigned char)*q))
516 q++;
517 if (*q == '\0') {
518 /*
519 * All digits after the ":" until the end.
520 * Strip off the ":" and everything after
521 * it.
522 */
523 *p = '\0';
524 }
525 }
526 #endif
527
528 /*
529 * Add information for this address to the list.
530 */
531 if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
532 ifrflags.ifr_flags, &ifrp->ifr_addr,
533 SA_LEN(&ifrp->ifr_addr), netmask, netmask_size,
534 broadaddr, broadaddr_size, dstaddr, dstaddr_size,
535 errbuf) < 0) {
536 ret = -1;
537 break;
538 }
539 }
540 free(buf);
541
542 #ifdef HAVE_PROC_NET_DEV
543 if (ret != -1) {
544 /*
545 * We haven't had any errors yet; now read "/proc/net/dev",
546 * and add to the list of interfaces all interfaces listed
547 * there that we don't already have, because, on Linux,
548 * SIOCGIFCONF reports only interfaces with IPv4 addresses,
549 * so you need to read "/proc/net/dev" to get the names of
550 * the rest of the interfaces.
551 */
552 ret = scan_proc_net_dev(&devlist, fd, errbuf);
553 }
554 #endif
555 (void)close(fd);
556
557 if (ret != -1) {
558 /*
559 * We haven't had any errors yet; do any platform-specific
560 * operations to add devices.
561 */
562 if (pcap_platform_finddevs(&devlist, errbuf) < 0)
563 ret = -1;
564 }
565
566 if (ret == -1) {
567 /*
568 * We had an error; free the list we've been constructing.
569 */
570 if (devlist != NULL) {
571 pcap_freealldevs(devlist);
572 devlist = NULL;
573 }
574 }
575
576 *alldevsp = devlist;
577 return (ret);
578 }
579