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1 office 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
135 pcap_findalldevs_interfaces(pcap_if_t **alldevsp, char *errbuf)
136 {
137 pcap_if_t *devlist = NULL;
138 register int fd;
139 register struct ifreq *ifrp, *ifend, *ifnext;
140 int n;
141 struct ifconf ifc;
142 char *buf = NULL;
143 unsigned buf_size;
144 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
145 char *p, *q;
146 #endif
147 struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
148 struct sockaddr *netmask, *broadaddr, *dstaddr;
149 size_t netmask_size, broadaddr_size, dstaddr_size;
150 int ret = 0;
151  
152 /*
153 * Create a socket from which to fetch the list of interfaces.
154 */
155 fd = socket(AF_INET, SOCK_DGRAM, 0);
156 if (fd < 0) {
157 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
158 "socket: %s", pcap_strerror(errno));
159 return (-1);
160 }
161  
162 /*
163 * Start with an 8K buffer, and keep growing the buffer until
164 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
165 * bytes left over in the buffer or we fail to get the
166 * interface list for some reason other than EINVAL (which is
167 * presumed here to mean "buffer is too small").
168 */
169 buf_size = 8192;
170 for (;;) {
171 buf = malloc(buf_size);
172 if (buf == NULL) {
173 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
174 "malloc: %s", pcap_strerror(errno));
175 (void)close(fd);
176 return (-1);
177 }
178  
179 ifc.ifc_len = buf_size;
180 ifc.ifc_buf = buf;
181 memset(buf, 0, buf_size);
182 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
183 && errno != EINVAL) {
184 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
185 "SIOCGIFCONF: %s", pcap_strerror(errno));
186 (void)close(fd);
187 free(buf);
188 return (-1);
189 }
190 if (ifc.ifc_len < buf_size &&
191 (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
192 break;
193 free(buf);
194 buf_size *= 2;
195 }
196  
197 ifrp = (struct ifreq *)buf;
198 ifend = (struct ifreq *)(buf + ifc.ifc_len);
199  
200 for (; ifrp < ifend; ifrp = ifnext) {
201 /*
202 * XXX - what if this isn't an IPv4 address? Can
203 * we still get the netmask, etc. with ioctls on
204 * an IPv4 socket?
205 *
206 * The answer is probably platform-dependent, and
207 * if the answer is "no" on more than one platform,
208 * the way you work around it is probably platform-
209 * dependent as well.
210 */
211 n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
212 if (n < sizeof(*ifrp))
213 ifnext = ifrp + 1;
214 else
215 ifnext = (struct ifreq *)((char *)ifrp + n);
216  
217 /*
218 * XXX - The 32-bit compatibility layer for Linux on IA-64
219 * is slightly broken. It correctly converts the structures
220 * to and from kernel land from 64 bit to 32 bit but
221 * doesn't update ifc.ifc_len, leaving it larger than the
222 * amount really used. This means we read off the end
223 * of the buffer and encounter an interface with an
224 * "empty" name. Since this is highly unlikely to ever
225 * occur in a valid case we can just finish looking for
226 * interfaces if we see an empty name.
227 */
228 if (!(*ifrp->ifr_name))
229 break;
230  
231 /*
232 * Skip entries that begin with "dummy".
233 * XXX - what are these? Is this Linux-specific?
234 * Are there platforms on which we shouldn't do this?
235 */
236 if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
237 continue;
238  
239 /*
240 * Get the flags for this interface.
241 */
242 strncpy(ifrflags.ifr_name, ifrp->ifr_name,
243 sizeof(ifrflags.ifr_name));
244 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
245 if (errno == ENXIO)
246 continue;
247 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
248 "SIOCGIFFLAGS: %.*s: %s",
249 (int)sizeof(ifrflags.ifr_name),
250 ifrflags.ifr_name,
251 pcap_strerror(errno));
252 ret = -1;
253 break;
254 }
255  
256 /*
257 * Get the netmask for this address on this interface.
258 */
259 strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
260 sizeof(ifrnetmask.ifr_name));
261 memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
262 sizeof(ifrnetmask.ifr_addr));
263 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
264 if (errno == EADDRNOTAVAIL) {
265 /*
266 * Not available.
267 */
268 netmask = NULL;
269 netmask_size = 0;
270 } else {
271 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
272 "SIOCGIFNETMASK: %.*s: %s",
273 (int)sizeof(ifrnetmask.ifr_name),
274 ifrnetmask.ifr_name,
275 pcap_strerror(errno));
276 ret = -1;
277 break;
278 }
279 } else {
280 netmask = &ifrnetmask.ifr_addr;
281 netmask_size = SA_LEN(netmask);
282 }
283  
284 /*
285 * Get the broadcast address for this address on this
286 * interface (if any).
287 */
288 if (ifrflags.ifr_flags & IFF_BROADCAST) {
289 strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
290 sizeof(ifrbroadaddr.ifr_name));
291 memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
292 sizeof(ifrbroadaddr.ifr_addr));
293 if (ioctl(fd, SIOCGIFBRDADDR,
294 (char *)&ifrbroadaddr) < 0) {
295 if (errno == EADDRNOTAVAIL) {
296 /*
297 * Not available.
298 */
299 broadaddr = NULL;
300 broadaddr_size = 0;
301 } else {
302 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
303 "SIOCGIFBRDADDR: %.*s: %s",
304 (int)sizeof(ifrbroadaddr.ifr_name),
305 ifrbroadaddr.ifr_name,
306 pcap_strerror(errno));
307 ret = -1;
308 break;
309 }
310 } else {
311 broadaddr = &ifrbroadaddr.ifr_broadaddr;
312 broadaddr_size = SA_LEN(broadaddr);
313 }
314 } else {
315 /*
316 * Not a broadcast interface, so no broadcast
317 * address.
318 */
319 broadaddr = NULL;
320 broadaddr_size = 0;
321 }
322  
323 /*
324 * Get the destination address for this address on this
325 * interface (if any).
326 */
327 if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
328 strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
329 sizeof(ifrdstaddr.ifr_name));
330 memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
331 sizeof(ifrdstaddr.ifr_addr));
332 if (ioctl(fd, SIOCGIFDSTADDR,
333 (char *)&ifrdstaddr) < 0) {
334 if (errno == EADDRNOTAVAIL) {
335 /*
336 * Not available.
337 */
338 dstaddr = NULL;
339 dstaddr_size = 0;
340 } else {
341 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
342 "SIOCGIFDSTADDR: %.*s: %s",
343 (int)sizeof(ifrdstaddr.ifr_name),
344 ifrdstaddr.ifr_name,
345 pcap_strerror(errno));
346 ret = -1;
347 break;
348 }
349 } else {
350 dstaddr = &ifrdstaddr.ifr_dstaddr;
351 dstaddr_size = SA_LEN(dstaddr);
352 }
353 } else {
354 /*
355 * Not a point-to-point interface, so no destination
356 * address.
357 */
358 dstaddr = NULL;
359 dstaddr_size = 0;
360 }
361  
362 #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
363 /*
364 * If this entry has a colon followed by a number at
365 * the end, it's a logical interface. Those are just
366 * the way you assign multiple IP addresses to a real
367 * interface, so an entry for a logical interface should
368 * be treated like the entry for the real interface;
369 * we do that by stripping off the ":" and the number.
370 */
371 p = strchr(ifrp->ifr_name, ':');
372 if (p != NULL) {
373 /*
374 * We have a ":"; is it followed by a number?
375 */
376 q = p + 1;
377 while (isdigit((unsigned char)*q))
378 q++;
379 if (*q == '\0') {
380 /*
381 * All digits after the ":" until the end.
382 * Strip off the ":" and everything after
383 * it.
384 */
385 *p = '\0';
386 }
387 }
388 #endif
389  
390 /*
391 * Add information for this address to the list.
392 */
393 if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
394 ifrflags.ifr_flags, &ifrp->ifr_addr,
395 SA_LEN(&ifrp->ifr_addr), netmask, netmask_size,
396 broadaddr, broadaddr_size, dstaddr, dstaddr_size,
397 errbuf) < 0) {
398 ret = -1;
399 break;
400 }
401 }
402 free(buf);
403 (void)close(fd);
404  
405 if (ret == -1) {
406 /*
407 * We had an error; free the list we've been constructing.
408 */
409 if (devlist != NULL) {
410 pcap_freealldevs(devlist);
411 devlist = NULL;
412 }
413 }
414  
415 *alldevsp = devlist;
416 return (ret);
417 }