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 #include <config.h>
36
37 #include <sys/param.h>
38 #include <sys/ioctl.h>
39 #include <sys/socket.h>
40 #ifdef HAVE_SYS_SOCKIO_H
41 #include <sys/sockio.h>
42 #endif
43 #include <sys/time.h> /* concession to AIX */
44
45 struct mbuf; /* Squelch compiler warnings on some platforms for */
46 struct rtentry; /* declarations in <net/if.h> */
47 #include <net/if.h>
48 #include <netinet/in.h>
49
50 #include <errno.h>
51 #include <memory.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <unistd.h>
56 #include <limits.h>
57
58 #include "pcap-int.h"
59
60 #ifdef HAVE_OS_PROTO_H
61 #include "os-proto.h"
62 #endif
63
64 /*
65 * This is fun.
66 *
67 * In older BSD systems, socket addresses were fixed-length, and
68 * "sizeof (struct sockaddr)" gave the size of the structure.
69 * All addresses fit within a "struct sockaddr".
70 *
71 * In newer BSD systems, the socket address is variable-length, and
72 * there's an "sa_len" field giving the length of the structure;
73 * this allows socket addresses to be longer than 2 bytes of family
74 * and 14 bytes of data.
75 *
76 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
77 * variant of the old BSD scheme (with "struct sockaddr_storage" rather
78 * than "struct sockaddr"), and some use the new BSD scheme.
79 *
80 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
81 * macro that determines the size based on the address family. Other
82 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
83 * but not in the final version).
84 *
85 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
86 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
87 * address in an entry returned by SIOCGIFCONF.
88 *
89 * OSes that use this file are:
90 * - AIX 7 (SA_LEN() is not defined, HAVE_STRUCT_SOCKADDR_SA_LEN is defined)
91 * - HP-UX 11 (HAVE_STRUCT_SOCKADDR_SA_LEN is not defined)
92 */
93 #ifndef SA_LEN
94 #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
95 #define SA_LEN(addr) ((addr)->sa_len)
96 #else /* HAVE_STRUCT_SOCKADDR_SA_LEN */
97 #define SA_LEN(addr) (sizeof (struct sockaddr))
98 #endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
99 #endif /* SA_LEN */
100
101 /*
102 * This is also fun.
103 *
104 * There is no ioctl that returns the amount of space required for all
105 * the data that SIOCGIFCONF could return, and if a buffer is supplied
106 * that's not large enough for all the data SIOCGIFCONF could return,
107 * on at least some platforms it just returns the data that'd fit with
108 * no indication that there wasn't enough room for all the data, much
109 * less an indication of how much more room is required.
110 *
111 * The only way to ensure that we got all the data is to pass a buffer
112 * large enough that the amount of space in the buffer *not* filled in
113 * is greater than the largest possible entry.
114 *
115 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
116 * that no address is more than 255 bytes (on systems where the "sa_len"
117 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
118 * case, and addresses are unlikely to be bigger than that in any case).
119 */
120 #define MAX_SA_LEN 255
121
122 /*
123 * Get a list of all interfaces that are up and that we can open.
124 * Returns -1 on error, 0 otherwise.
125 * The list, as returned through "alldevsp", may be null if no interfaces
126 * were up and could be opened.
127 *
128 * This is the implementation used on platforms that have SIOCGIFCONF but
129 * don't have any other mechanism for getting a list of interfaces.
130 *
131 * XXX - or platforms that have other, better mechanisms but for which
132 * we don't yet have code to use that mechanism; I think there's a better
133 * way on Linux, for example, but if that better way is "getifaddrs()",
134 * we already have that.
135 */
136 int
pcapint_findalldevs_interfaces(pcap_if_list_t * devlistp,char * errbuf,int (* check_usable)(const char *),get_if_flags_func get_flags_func)137 pcapint_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf,
138 int (*check_usable)(const char *), get_if_flags_func get_flags_func)
139 {
140 register int fd;
141 register struct ifreq *ifrp, *ifend, *ifnext;
142 size_t n;
143 struct ifconf ifc;
144 char *buf = NULL;
145 unsigned buf_size;
146 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
147 char *p, *q;
148 #endif
149 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
150 struct sockaddr *netmask, *broadaddr, *dstaddr;
151 size_t netmask_size, broadaddr_size, dstaddr_size;
152 int ret = 0;
153
154 /*
155 * Create a socket from which to fetch the list of interfaces.
156 */
157 fd = socket(AF_INET, SOCK_DGRAM, 0);
158 if (fd < 0) {
159 pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
160 errno, "socket");
161 return (-1);
162 }
163
164 /*
165 * Start with an 8K buffer, and keep growing the buffer until
166 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
167 * bytes left over in the buffer or we fail to get the
168 * interface list for some reason other than EINVAL (which is
169 * presumed here to mean "buffer is too small").
170 */
171 buf_size = 8192;
172 for (;;) {
173 /*
174 * Don't let the buffer size get bigger than INT_MAX.
175 */
176 if (buf_size > INT_MAX) {
177 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
178 "interface information requires more than %u bytes",
179 INT_MAX);
180 (void)close(fd);
181 return (-1);
182 }
183 buf = malloc(buf_size);
184 if (buf == NULL) {
185 pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
186 errno, "malloc");
187 (void)close(fd);
188 return (-1);
189 }
190
191 ifc.ifc_len = buf_size;
192 ifc.ifc_buf = buf;
193 memset(buf, 0, buf_size);
194 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
195 && errno != EINVAL) {
196 pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
197 errno, "SIOCGIFCONF");
198 (void)close(fd);
199 free(buf);
200 return (-1);
201 }
202 if (ifc.ifc_len < (int)buf_size &&
203 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
204 break;
205 free(buf);
206 buf_size *= 2;
207 }
208
209 ifrp = (struct ifreq *)buf;
210 ifend = (struct ifreq *)(buf + ifc.ifc_len);
211
212 for (; ifrp < ifend; ifrp = ifnext) {
213 /*
214 * XXX - what if this isn't an IPv4 address? Can
215 * we still get the netmask, etc. with ioctls on
216 * an IPv4 socket?
217 *
218 * The answer is probably platform-dependent, and
219 * if the answer is "no" on more than one platform,
220 * the way you work around it is probably platform-
221 * dependent as well.
222 */
223 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
224 if (n < sizeof(*ifrp))
225 ifnext = ifrp + 1;
226 else
227 ifnext = (struct ifreq *)((char *)ifrp + n);
228
229 /*
230 * XXX - The 32-bit compatibility layer for Linux on IA-64
231 * is slightly broken. It correctly converts the structures
232 * to and from kernel land from 64 bit to 32 bit but
233 * doesn't update ifc.ifc_len, leaving it larger than the
234 * amount really used. This means we read off the end
235 * of the buffer and encounter an interface with an
236 * "empty" name. Since this is highly unlikely to ever
237 * occur in a valid case we can just finish looking for
238 * interfaces if we see an empty name.
239 */
240 if (!(*ifrp->ifr_name))
241 break;
242
243 /*
244 * Skip entries that begin with "dummy".
245 * XXX - what are these? Is this Linux-specific?
246 * Are there platforms on which we shouldn't do this?
247 */
248 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
249 continue;
250
251 /*
252 * Can we capture on this device?
253 */
254 if (!(*check_usable)(ifrp->ifr_name)) {
255 /*
256 * No.
257 */
258 continue;
259 }
260
261 /*
262 * Get the flags for this interface.
263 */
264 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
265 sizeof(ifrflags.ifr_name));
266 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
267 if (errno == ENXIO)
268 continue;
269 pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
270 errno, "SIOCGIFFLAGS: %.*s",
271 (int)sizeof(ifrflags.ifr_name),
272 ifrflags.ifr_name);
273 ret = -1;
274 break;
275 }
276
277 /*
278 * Get the netmask for this address on this interface.
279 */
280 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
281 sizeof(ifrnetmask.ifr_name));
282 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
283 sizeof(ifrnetmask.ifr_addr));
284 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
285 if (errno == EADDRNOTAVAIL) {
286 /*
287 * Not available.
288 */
289 netmask = NULL;
290 netmask_size = 0;
291 } else {
292 pcapint_fmt_errmsg_for_errno(errbuf,
293 PCAP_ERRBUF_SIZE, errno,
294 "SIOCGIFNETMASK: %.*s",
295 (int)sizeof(ifrnetmask.ifr_name),
296 ifrnetmask.ifr_name);
297 ret = -1;
298 break;
299 }
300 } else {
301 netmask = &ifrnetmask.ifr_addr;
302 netmask_size = SA_LEN(netmask);
303 }
304
305 /*
306 * Get the broadcast address for this address on this
307 * interface (if any).
308 */
309 if (ifrflags.ifr_flags & IFF_BROADCAST) {
310 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
311 sizeof(ifrbroadaddr.ifr_name));
312 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
313 sizeof(ifrbroadaddr.ifr_addr));
314 if (ioctl(fd, SIOCGIFBRDADDR,
315 (char *)&ifrbroadaddr) < 0) {
316 if (errno == EADDRNOTAVAIL) {
317 /*
318 * Not available.
319 */
320 broadaddr = NULL;
321 broadaddr_size = 0;
322 } else {
323 pcapint_fmt_errmsg_for_errno(errbuf,
324 PCAP_ERRBUF_SIZE, errno,
325 "SIOCGIFBRDADDR: %.*s",
326 (int)sizeof(ifrbroadaddr.ifr_name),
327 ifrbroadaddr.ifr_name);
328 ret = -1;
329 break;
330 }
331 } else {
332 broadaddr = &ifrbroadaddr.ifr_broadaddr;
333 broadaddr_size = SA_LEN(broadaddr);
334 }
335 } else {
336 /*
337 * Not a broadcast interface, so no broadcast
338 * address.
339 */
340 broadaddr = NULL;
341 broadaddr_size = 0;
342 }
343
344 /*
345 * Get the destination address for this address on this
346 * interface (if any).
347 */
348 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
349 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
350 sizeof(ifrdstaddr.ifr_name));
351 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
352 sizeof(ifrdstaddr.ifr_addr));
353 if (ioctl(fd, SIOCGIFDSTADDR,
354 (char *)&ifrdstaddr) < 0) {
355 if (errno == EADDRNOTAVAIL) {
356 /*
357 * Not available.
358 */
359 dstaddr = NULL;
360 dstaddr_size = 0;
361 } else {
362 pcapint_fmt_errmsg_for_errno(errbuf,
363 PCAP_ERRBUF_SIZE, errno,
364 "SIOCGIFDSTADDR: %.*s",
365 (int)sizeof(ifrdstaddr.ifr_name),
366 ifrdstaddr.ifr_name);
367 ret = -1;
368 break;
369 }
370 } else {
371 dstaddr = &ifrdstaddr.ifr_dstaddr;
372 dstaddr_size = SA_LEN(dstaddr);
373 }
374 } else {
375 /*
376 * Not a point-to-point interface, so no destination
377 * address.
378 */
379 dstaddr = NULL;
380 dstaddr_size = 0;
381 }
382
383 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
384 /*
385 * If this entry has a colon followed by a number at
386 * the end, it's a logical interface. Those are just
387 * the way you assign multiple IP addresses to a real
388 * interface, so an entry for a logical interface should
389 * be treated like the entry for the real interface;
390 * we do that by stripping off the ":" and the number.
391 */
392 p = strchr(ifrp->ifr_name, ':');
393 if (p != NULL) {
394 /*
395 * We have a ":"; is it followed by a number?
396 */
397 q = p + 1;
398 while (PCAP_ISDIGIT(*q))
399 q++;
400 if (*q == '\0') {
401 /*
402 * All digits after the ":" until the end.
403 * Strip off the ":" and everything after
404 * it.
405 */
406 *p = '\0';
407 }
408 }
409 #endif
410
411 /*
412 * Add information for this address to the list.
413 */
414 if (pcapint_add_addr_to_if(devlistp, ifrp->ifr_name,
415 ifrflags.ifr_flags, get_flags_func,
416 &ifrp->ifr_addr, SA_LEN(&ifrp->ifr_addr),
417 netmask, netmask_size, broadaddr, broadaddr_size,
418 dstaddr, dstaddr_size, errbuf) < 0) {
419 ret = -1;
420 break;
421 }
422 }
423 free(buf);
424 (void)close(fd);
425
426 return (ret);
427 }
428