summaryrefslogtreecommitdiffstats
path: root/contrib/libpcap/fad-gifc.c
blob: 0214d59d0217eff699bfd9698649c48c34078f36 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
/* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
/*
 * Copyright (c) 1994, 1995, 1996, 1997, 1998
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the Computer Systems
 *	Engineering Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static const char rcsid[] _U_ =
    "@(#) $Header: /tcpdump/master/libpcap/fad-gifc.c,v 1.4.2.1 2003/11/15 23:26:39 guy Exp $ (LBL)";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/param.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif
#include <sys/time.h>				/* concession to AIX */

struct mbuf;		/* Squelch compiler warnings on some platforms for */
struct rtentry;		/* declarations in <net/if.h> */
#include <net/if.h>
#include <netinet/in.h>

#include <ctype.h>
#include <errno.h>
#include <memory.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "pcap-int.h"

#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif

/*
 * This is fun.
 *
 * In older BSD systems, socket addresses were fixed-length, and
 * "sizeof (struct sockaddr)" gave the size of the structure.
 * All addresses fit within a "struct sockaddr".
 *
 * In newer BSD systems, the socket address is variable-length, and
 * there's an "sa_len" field giving the length of the structure;
 * this allows socket addresses to be longer than 2 bytes of family
 * and 14 bytes of data.
 *
 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
 * variant of the old BSD scheme (with "struct sockaddr_storage" rather
 * than "struct sockaddr"), and some use the new BSD scheme.
 *
 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
 * macro that determines the size based on the address family.  Other
 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
 * but not in the final version).
 *
 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
 * address in an entry returned by SIOCGIFCONF.
 */
#ifndef SA_LEN
#ifdef HAVE_SOCKADDR_SA_LEN
#define SA_LEN(addr)	((addr)->sa_len)
#else /* HAVE_SOCKADDR_SA_LEN */
#define SA_LEN(addr)	(sizeof (struct sockaddr))
#endif /* HAVE_SOCKADDR_SA_LEN */
#endif /* SA_LEN */

#ifdef HAVE_PROC_NET_DEV
/*
 * Get from "/proc/net/dev" all interfaces listed there; if they're
 * already in the list of interfaces we have, that won't add another
 * instance, but if they're not, that'll add them.
 *
 * We don't bother getting any addresses for them; it appears you can't
 * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
 * although some other types of addresses can be fetched with SIOCGIFADDR,
 * we don't bother with them for now.
 *
 * We also don't fail if we couldn't open "/proc/net/dev"; we just leave
 * the list of interfaces as is.
 */
static int
scan_proc_net_dev(pcap_if_t **devlistp, int fd, char *errbuf)
{
	FILE *proc_net_f;
	char linebuf[512];
	int linenum;
	unsigned char *p;
	char name[512];	/* XXX - pick a size */
	char *q, *saveq;
	struct ifreq ifrflags;
	int ret = 0;

	proc_net_f = fopen("/proc/net/dev", "r");
	if (proc_net_f == NULL)
		return (0);

	for (linenum = 1;
	    fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
		/*
		 * Skip the first two lines - they're headers.
		 */
		if (linenum <= 2)
			continue;

		p = &linebuf[0];

		/*
		 * Skip leading white space.
		 */
		while (*p != '\0' && isspace(*p))
			p++;
		if (*p == '\0' || *p == '\n')
			continue;	/* blank line */

		/*
		 * Get the interface name.
		 */
		q = &name[0];
		while (*p != '\0' && !isspace(*p)) {
			if (*p == ':') {
				/*
				 * This could be the separator between a
				 * name and an alias number, or it could be
				 * the separator between a name with no
				 * alias number and the next field.
				 *
				 * If there's a colon after digits, it
				 * separates the name and the alias number,
				 * otherwise it separates the name and the
				 * next field.
				 */
				saveq = q;
				while (isdigit(*p))
					*q++ = *p++;
				if (*p != ':') {
					/*
					 * That was the next field,
					 * not the alias number.
					 */
					q = saveq;
				}
				break;
			} else
				*q++ = *p++;
		}
		*q = '\0';

		/*
		 * Get the flags for this interface, and skip it if
		 * it's not up.
		 */
		strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
		if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
			if (errno == ENXIO)
				continue;
			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
			    "SIOCGIFFLAGS: %.*s: %s",
			    (int)sizeof(ifrflags.ifr_name),
			    ifrflags.ifr_name,
			    pcap_strerror(errno));
			ret = -1;
			break;
		}
		if (!(ifrflags.ifr_flags & IFF_UP))
			continue;

		/*
		 * Add an entry for this interface, with no addresses.
		 */
		if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
		    errbuf) == -1) {
			/*
			 * Failure.
			 */
			ret = -1;
			break;
		}
	}
	if (ret != -1) {
		/*
		 * Well, we didn't fail for any other reason; did we
		 * fail due to an error reading the file?
		 */
		if (ferror(proc_net_f)) {
			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
			    "Error reading /proc/net/dev: %s",
			    pcap_strerror(errno));
			ret = -1;
		}
	}

	(void)fclose(proc_net_f);
	return (ret);
}
#endif /* HAVE_PROC_NET_DEV */

/*
 * Get a list of all interfaces that are up and that we can open.
 * Returns -1 on error, 0 otherwise.
 * The list, as returned through "alldevsp", may be null if no interfaces
 * were up and could be opened.
 *
 * This is the implementation used on platforms that have SIOCGIFCONF but
 * don't have any other mechanism for getting a list of interfaces.
 *
 * XXX - or platforms that have other, better mechanisms but for which
 * we don't yet have code to use that mechanism; I think there's a better
 * way on Linux, for example.
 */
int
pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf)
{
	pcap_if_t *devlist = NULL;
	register int fd;
	register struct ifreq *ifrp, *ifend, *ifnext;
	int n;
	struct ifconf ifc;
	char *buf = NULL;
	unsigned buf_size;
	struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
	struct sockaddr *netmask, *broadaddr, *dstaddr;
	size_t netmask_size, broadaddr_size, dstaddr_size;
	int ret = 0;

	/*
	 * Create a socket from which to fetch the list of interfaces.
	 */
	fd = socket(AF_INET, SOCK_DGRAM, 0);
	if (fd < 0) {
		(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
		    "socket: %s", pcap_strerror(errno));
		return (-1);
	}

	/*
	 * Start with an 8K buffer, and keep growing the buffer until
	 * we get the entire interface list or fail to get it for some
	 * reason other than EINVAL (which is presumed here to mean
	 * "buffer is too small").
	 */
	buf_size = 8192;
	for (;;) {
		buf = malloc(buf_size);
		if (buf == NULL) {
			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
			    "malloc: %s", pcap_strerror(errno));
			(void)close(fd);
			return (-1);
		}

		ifc.ifc_len = buf_size;
		ifc.ifc_buf = buf;
		memset(buf, 0, buf_size);
		if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
		    && errno != EINVAL) {
			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
			    "SIOCGIFCONF: %s", pcap_strerror(errno));
			(void)close(fd);
			free(buf);
			return (-1);
		}
		if (ifc.ifc_len < buf_size)
			break;
		free(buf);
		buf_size *= 2;
	}

	ifrp = (struct ifreq *)buf;
	ifend = (struct ifreq *)(buf + ifc.ifc_len);

	for (; ifrp < ifend; ifrp = ifnext) {
		/*
		 * XXX - what if this isn't an IPv4 address?  Can
		 * we still get the netmask, etc. with ioctls on
		 * an IPv4 socket?
		 *
		 * The answer is probably platform-dependent, and
		 * if the answer is "no" on more than one platform,
		 * the way you work around it is probably platform-
		 * dependent as well.
		 */
		n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
		if (n < sizeof(*ifrp))
			ifnext = ifrp + 1;
		else
			ifnext = (struct ifreq *)((char *)ifrp + n);

		/*
		 * Get the flags for this interface, and skip it if it's
		 * not up.
		 */
		strncpy(ifrflags.ifr_name, ifrp->ifr_name,
		    sizeof(ifrflags.ifr_name));
		if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
			if (errno == ENXIO)
				continue;
			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
			    "SIOCGIFFLAGS: %.*s: %s",
			    (int)sizeof(ifrflags.ifr_name),
			    ifrflags.ifr_name,
			    pcap_strerror(errno));
			ret = -1;
			break;
		}
		if (!(ifrflags.ifr_flags & IFF_UP))
			continue;

		/*
		 * Get the netmask for this address on this interface.
		 */
		strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
		    sizeof(ifrnetmask.ifr_name));
		memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
		    sizeof(ifrnetmask.ifr_addr));
		if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
			if (errno == EADDRNOTAVAIL) {
				/*
				 * Not available.
				 */
				netmask = NULL;
				netmask_size = 0;
			} else {
				(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
				    "SIOCGIFNETMASK: %.*s: %s",
				    (int)sizeof(ifrnetmask.ifr_name),
				    ifrnetmask.ifr_name,
				    pcap_strerror(errno));
				ret = -1;
				break;
			}
		} else {
			netmask = &ifrnetmask.ifr_addr;
			netmask_size = SA_LEN(netmask);
		}

		/*
		 * Get the broadcast address for this address on this
		 * interface (if any).
		 */
		if (ifrflags.ifr_flags & IFF_BROADCAST) {
			strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
			    sizeof(ifrbroadaddr.ifr_name));
			memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
			    sizeof(ifrbroadaddr.ifr_addr));
			if (ioctl(fd, SIOCGIFBRDADDR,
			    (char *)&ifrbroadaddr) < 0) {
				if (errno == EADDRNOTAVAIL) {
					/*
					 * Not available.
					 */
					broadaddr = NULL;
					broadaddr_size = 0;
				} else {
					(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
					    "SIOCGIFBRDADDR: %.*s: %s",
					    (int)sizeof(ifrbroadaddr.ifr_name),
					    ifrbroadaddr.ifr_name,
					    pcap_strerror(errno));
					ret = -1;
					break;
				}
			} else {
				broadaddr = &ifrbroadaddr.ifr_broadaddr;
				broadaddr_size = SA_LEN(broadaddr);
			}
		} else {
			/*
			 * Not a broadcast interface, so no broadcast
			 * address.
			 */
			broadaddr = NULL;
			broadaddr_size = 0;
		}

		/*
		 * Get the destination address for this address on this
		 * interface (if any).
		 */
		if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
			strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
			    sizeof(ifrdstaddr.ifr_name));
			memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
			    sizeof(ifrdstaddr.ifr_addr));
			if (ioctl(fd, SIOCGIFDSTADDR,
			    (char *)&ifrdstaddr) < 0) {
				if (errno == EADDRNOTAVAIL) {
					/*
					 * Not available.
					 */
					dstaddr = NULL;
					dstaddr_size = 0;
				} else {
					(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
					    "SIOCGIFDSTADDR: %.*s: %s",
					    (int)sizeof(ifrdstaddr.ifr_name),
					    ifrdstaddr.ifr_name,
					    pcap_strerror(errno));
					ret = -1;
					break;
				}
			} else {
				dstaddr = &ifrdstaddr.ifr_dstaddr;
				dstaddr_size = SA_LEN(dstaddr);
			}
		} else {
			/*
			 * Not a point-to-point interface, so no destination
			 * address.
			 */
			dstaddr = NULL;
			dstaddr_size = 0;
		}

		/*
		 * Add information for this address to the list.
		 */
		if (add_addr_to_iflist(&devlist, ifrp->ifr_name,
		    ifrflags.ifr_flags, &ifrp->ifr_addr,
		    SA_LEN(&ifrp->ifr_addr), netmask, netmask_size,
		    broadaddr, broadaddr_size, dstaddr, dstaddr_size,
		    errbuf) < 0) {
			ret = -1;
			break;
		}
	}
	free(buf);

#ifdef HAVE_PROC_NET_DEV
	if (ret != -1) {
		/*
		 * We haven't had any errors yet; now read "/proc/net/dev",
		 * and add to the list of interfaces all interfaces listed
		 * there that we don't already have, because, on Linux,
		 * SIOCGIFCONF reports only interfaces with IPv4 addresses,
		 * so you need to read "/proc/net/dev" to get the names of
		 * the rest of the interfaces.
		 */
		ret = scan_proc_net_dev(&devlist, fd, errbuf);
	}
#endif
	(void)close(fd);

	if (ret != -1) {
		/*
		 * We haven't had any errors yet; do any platform-specific
		 * operations to add devices.
		 */
		if (pcap_platform_finddevs(&devlist, errbuf) < 0)
			ret = -1;
	}

	if (ret == -1) {
		/*
		 * We had an error; free the list we've been constructing.
		 */
		if (devlist != NULL) {
			pcap_freealldevs(devlist);
			devlist = NULL;
		}
	}

	*alldevsp = devlist;
	return (ret);
}
OpenPOWER on IntegriCloud