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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/inet.c,v 1.66.2.6 2007/06/11 09:52:04 guy Exp $ (LBL)";
38 #endif
39 
40 #ifdef HAVE_CONFIG_H
41 #include "config.h"
42 #endif
43 
44 #ifdef WIN32
45 #include <pcap-stdinc.h>
46 #else /* WIN32 */
47 
48 #include <sys/param.h>
49 #ifndef MSDOS
50 #include <sys/file.h>
51 #endif
52 #include <sys/ioctl.h>
53 #include <sys/socket.h>
54 #ifdef HAVE_SYS_SOCKIO_H
55 #include <sys/sockio.h>
56 #endif
57 
58 struct mbuf;		/* Squelch compiler warnings on some platforms for */
59 struct rtentry;		/* declarations in <net/if.h> */
60 #include <net/if.h>
61 #include <netinet/in.h>
62 #endif /* WIN32 */
63 
64 #include <ctype.h>
65 #include <errno.h>
66 #include <memory.h>
67 #include <stdio.h>
68 #include <stdlib.h>
69 #include <string.h>
70 #if !defined(WIN32) && !defined(__BORLANDC__)
71 #include <unistd.h>
72 #endif /* !WIN32 && !__BORLANDC__ */
73 #ifdef HAVE_LIMITS_H
74 #include <limits.h>
75 #else
76 #define INT_MAX		2147483647
77 #endif
78 
79 #include "pcap-int.h"
80 
81 #ifdef HAVE_OS_PROTO_H
82 #include "os-proto.h"
83 #endif
84 
85 /* Not all systems have IFF_LOOPBACK */
86 #ifdef IFF_LOOPBACK
87 #define ISLOOPBACK(name, flags) ((flags) & IFF_LOOPBACK)
88 #else
89 #define ISLOOPBACK(name, flags) ((name)[0] == 'l' && (name)[1] == 'o' && \
90     (isdigit((unsigned char)((name)[2])) || (name)[2] == '\0'))
91 #endif
92 
93 struct sockaddr *
dup_sockaddr(struct sockaddr * sa,size_t sa_length)94 dup_sockaddr(struct sockaddr *sa, size_t sa_length)
95 {
96 	struct sockaddr *newsa;
97 
98 	if ((newsa = malloc(sa_length)) == NULL)
99 		return (NULL);
100 	return (memcpy(newsa, sa, sa_length));
101 }
102 
103 static int
get_instance(const char * name)104 get_instance(const char *name)
105 {
106 	const char *cp, *endcp;
107 	int n;
108 
109 	if (strcmp(name, "any") == 0) {
110 		/*
111 		 * Give the "any" device an artificially high instance
112 		 * number, so it shows up after all other non-loopback
113 		 * interfaces.
114 		 */
115 		return INT_MAX;
116 	}
117 
118 	endcp = name + strlen(name);
119 	for (cp = name; cp < endcp && !isdigit((unsigned char)*cp); ++cp)
120 		continue;
121 
122 	if (isdigit((unsigned char)*cp))
123 		n = atoi(cp);
124 	else
125 		n = 0;
126 	return (n);
127 }
128 
129 int
add_or_find_if(pcap_if_t ** curdev_ret,pcap_if_t ** alldevs,const char * name,u_int flags,const char * description,char * errbuf)130 add_or_find_if(pcap_if_t **curdev_ret, pcap_if_t **alldevs, const char *name,
131     u_int flags, const char *description, char *errbuf)
132 {
133 	pcap_t *p;
134 	pcap_if_t *curdev, *prevdev, *nextdev;
135 	int this_instance;
136 
137 	/*
138 	 * Is there already an entry in the list for this interface?
139 	 */
140 	for (curdev = *alldevs; curdev != NULL; curdev = curdev->next) {
141 		if (strcmp(name, curdev->name) == 0)
142 			break;	/* yes, we found it */
143 	}
144 
145 	if (curdev == NULL) {
146 		/*
147 		 * No, we didn't find it.
148 		 *
149 		 * Can we open this interface for live capture?
150 		 *
151 		 * We do this check so that interfaces that are
152 		 * supplied by the interface enumeration mechanism
153 		 * we're using but that don't support packet capture
154 		 * aren't included in the list.  Loopback interfaces
155 		 * on Solaris are an example of this; we don't just
156 		 * omit loopback interfaces on all platforms because
157 		 * you *can* capture on loopback interfaces on some
158 		 * OSes.
159 		 *
160 		 * On OS X, we don't do this check if the device
161 		 * name begins with "wlt"; at least some versions
162 		 * of OS X offer monitor mode capturing by having
163 		 * a separate "monitor mode" device for each wireless
164 		 * adapter, rather than by implementing the ioctls
165 		 * that {Free,Net,Open,DragonFly}BSD provide.
166 		 * Opening that device puts the adapter into monitor
167 		 * mode, which, at least for some adapters, causes
168 		 * them to deassociate from the network with which
169 		 * they're associated.
170 		 *
171 		 * Instead, we try to open the corresponding "en"
172 		 * device (so that we don't end up with, for users
173 		 * without sufficient privilege to open capture
174 		 * devices, a list of adapters that only includes
175 		 * the wlt devices).
176 		 */
177 #ifdef __APPLE__
178 		if (strncmp(name, "wlt", 3) == 0) {
179 			char *en_name;
180 			size_t en_name_len;
181 
182 			/*
183 			 * Try to allocate a buffer for the "en"
184 			 * device's name.
185 			 */
186 			en_name_len = strlen(name) - 1;
187 			en_name = malloc(en_name_len + 1);
188 			if (en_name == NULL) {
189 				(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
190 				    "malloc: %s", pcap_strerror(errno));
191 				return (-1);
192 			}
193 			strcpy(en_name, "en");
194 			strcat(en_name, name + 3);
195 			p = pcap_open_live(en_name, 68, 0, 0, errbuf);
196 			free(en_name);
197 		} else
198 #endif /* __APPLE */
199 		p = pcap_open_live(name, 68, 0, 0, errbuf);
200 		if (p == NULL) {
201 			/*
202 			 * No.  Don't bother including it.
203 			 * Don't treat this as an error, though.
204 			 */
205 			*curdev_ret = NULL;
206 			return (0);
207 		}
208 		pcap_close(p);
209 
210 		/*
211 		 * Yes, we can open it.
212 		 * Allocate a new entry.
213 		 */
214 		curdev = malloc(sizeof(pcap_if_t));
215 		if (curdev == NULL) {
216 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
217 			    "malloc: %s", pcap_strerror(errno));
218 			return (-1);
219 		}
220 
221 		/*
222 		 * Fill in the entry.
223 		 */
224 		curdev->next = NULL;
225 		curdev->name = strdup(name);
226 		if (curdev->name == NULL) {
227 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
228 			    "malloc: %s", pcap_strerror(errno));
229 			free(curdev);
230 			return (-1);
231 		}
232 		if (description != NULL) {
233 			/*
234 			 * We have a description for this interface.
235 			 */
236 			curdev->description = strdup(description);
237 			if (curdev->description == NULL) {
238 				(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
239 				    "malloc: %s", pcap_strerror(errno));
240 				free(curdev->name);
241 				free(curdev);
242 				return (-1);
243 			}
244 		} else {
245 			/*
246 			 * We don't.
247 			 */
248 			curdev->description = NULL;
249 		}
250 		curdev->addresses = NULL;	/* list starts out as empty */
251 		curdev->flags = 0;
252 		if (ISLOOPBACK(name, flags))
253 			curdev->flags |= PCAP_IF_LOOPBACK;
254 
255 		/*
256 		 * Add it to the list, in the appropriate location.
257 		 * First, get the instance number of this interface.
258 		 */
259 		this_instance = get_instance(name);
260 
261 		/*
262 		 * Now look for the last interface with an instance number
263 		 * less than or equal to the new interface's instance
264 		 * number - except that non-loopback interfaces are
265 		 * arbitrarily treated as having interface numbers less
266 		 * than those of loopback interfaces, so the loopback
267 		 * interfaces are put at the end of the list.
268 		 *
269 		 * We start with "prevdev" being NULL, meaning we're before
270 		 * the first element in the list.
271 		 */
272 		prevdev = NULL;
273 		for (;;) {
274 			/*
275 			 * Get the interface after this one.
276 			 */
277 			if (prevdev == NULL) {
278 				/*
279 				 * The next element is the first element.
280 				 */
281 				nextdev = *alldevs;
282 			} else
283 				nextdev = prevdev->next;
284 
285 			/*
286 			 * Are we at the end of the list?
287 			 */
288 			if (nextdev == NULL) {
289 				/*
290 				 * Yes - we have to put the new entry
291 				 * after "prevdev".
292 				 */
293 				break;
294 			}
295 
296 			/*
297 			 * Is the new interface a non-loopback interface
298 			 * and the next interface a loopback interface?
299 			 */
300 			if (!(curdev->flags & PCAP_IF_LOOPBACK) &&
301 			    (nextdev->flags & PCAP_IF_LOOPBACK)) {
302 				/*
303 				 * Yes, we should put the new entry
304 				 * before "nextdev", i.e. after "prevdev".
305 				 */
306 				break;
307 			}
308 
309 			/*
310 			 * Is the new interface's instance number less
311 			 * than the next interface's instance number,
312 			 * and is it the case that the new interface is a
313 			 * non-loopback interface or the next interface is
314 			 * a loopback interface?
315 			 *
316 			 * (The goal of both loopback tests is to make
317 			 * sure that we never put a loopback interface
318 			 * before any non-loopback interface and that we
319 			 * always put a non-loopback interface before all
320 			 * loopback interfaces.)
321 			 */
322 			if (this_instance < get_instance(nextdev->name) &&
323 			    (!(curdev->flags & PCAP_IF_LOOPBACK) ||
324 			       (nextdev->flags & PCAP_IF_LOOPBACK))) {
325 				/*
326 				 * Yes - we should put the new entry
327 				 * before "nextdev", i.e. after "prevdev".
328 				 */
329 				break;
330 			}
331 
332 			prevdev = nextdev;
333 		}
334 
335 		/*
336 		 * Insert before "nextdev".
337 		 */
338 		curdev->next = nextdev;
339 
340 		/*
341 		 * Insert after "prevdev" - unless "prevdev" is null,
342 		 * in which case this is the first interface.
343 		 */
344 		if (prevdev == NULL) {
345 			/*
346 			 * This is the first interface.  Pass back a
347 			 * pointer to it, and put "curdev" before
348 			 * "nextdev".
349 			 */
350 			*alldevs = curdev;
351 		} else
352 			prevdev->next = curdev;
353 	}
354 
355 	*curdev_ret = curdev;
356 	return (0);
357 }
358 
359 int
add_addr_to_iflist(pcap_if_t ** alldevs,const char * name,u_int flags,struct sockaddr * addr,size_t addr_size,struct sockaddr * netmask,size_t netmask_size,struct sockaddr * broadaddr,size_t broadaddr_size,struct sockaddr * dstaddr,size_t dstaddr_size,char * errbuf)360 add_addr_to_iflist(pcap_if_t **alldevs, const char *name, u_int flags,
361     struct sockaddr *addr, size_t addr_size,
362     struct sockaddr *netmask, size_t netmask_size,
363     struct sockaddr *broadaddr, size_t broadaddr_size,
364     struct sockaddr *dstaddr, size_t dstaddr_size,
365     char *errbuf)
366 {
367 	pcap_if_t *curdev;
368 	pcap_addr_t *curaddr, *prevaddr, *nextaddr;
369 
370 	if (add_or_find_if(&curdev, alldevs, name, flags, NULL, errbuf) == -1) {
371 		/*
372 		 * Error - give up.
373 		 */
374 		return (-1);
375 	}
376 	if (curdev == NULL) {
377 		/*
378 		 * Device wasn't added because it can't be opened.
379 		 * Not a fatal error.
380 		 */
381 		return (0);
382 	}
383 
384 	/*
385 	 * "curdev" is an entry for this interface; add an entry for this
386 	 * address to its list of addresses.
387 	 *
388 	 * Allocate the new entry and fill it in.
389 	 */
390 	curaddr = malloc(sizeof(pcap_addr_t));
391 	if (curaddr == NULL) {
392 		(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
393 		    "malloc: %s", pcap_strerror(errno));
394 		return (-1);
395 	}
396 
397 	curaddr->next = NULL;
398 	if (addr != NULL) {
399 		curaddr->addr = dup_sockaddr(addr, addr_size);
400 		if (curaddr->addr == NULL) {
401 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
402 			    "malloc: %s", pcap_strerror(errno));
403 			free(curaddr);
404 			return (-1);
405 		}
406 	} else
407 		curaddr->addr = NULL;
408 
409 	if (netmask != NULL) {
410 		curaddr->netmask = dup_sockaddr(netmask, netmask_size);
411 		if (curaddr->netmask == NULL) {
412 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
413 			    "malloc: %s", pcap_strerror(errno));
414 			if (curaddr->addr != NULL)
415 				free(curaddr->addr);
416 			free(curaddr);
417 			return (-1);
418 		}
419 	} else
420 		curaddr->netmask = NULL;
421 
422 	if (broadaddr != NULL) {
423 		curaddr->broadaddr = dup_sockaddr(broadaddr, broadaddr_size);
424 		if (curaddr->broadaddr == NULL) {
425 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
426 			    "malloc: %s", pcap_strerror(errno));
427 			if (curaddr->netmask != NULL)
428 				free(curaddr->netmask);
429 			if (curaddr->addr != NULL)
430 				free(curaddr->addr);
431 			free(curaddr);
432 			return (-1);
433 		}
434 	} else
435 		curaddr->broadaddr = NULL;
436 
437 	if (dstaddr != NULL) {
438 		curaddr->dstaddr = dup_sockaddr(dstaddr, dstaddr_size);
439 		if (curaddr->dstaddr == NULL) {
440 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
441 			    "malloc: %s", pcap_strerror(errno));
442 			if (curaddr->broadaddr != NULL)
443 				free(curaddr->broadaddr);
444 			if (curaddr->netmask != NULL)
445 				free(curaddr->netmask);
446 			if (curaddr->addr != NULL)
447 				free(curaddr->addr);
448 			free(curaddr);
449 			return (-1);
450 		}
451 	} else
452 		curaddr->dstaddr = NULL;
453 
454 	/*
455 	 * Find the end of the list of addresses.
456 	 */
457 	for (prevaddr = curdev->addresses; prevaddr != NULL; prevaddr = nextaddr) {
458 		nextaddr = prevaddr->next;
459 		if (nextaddr == NULL) {
460 			/*
461 			 * This is the end of the list.
462 			 */
463 			break;
464 		}
465 	}
466 
467 	if (prevaddr == NULL) {
468 		/*
469 		 * The list was empty; this is the first member.
470 		 */
471 		curdev->addresses = curaddr;
472 	} else {
473 		/*
474 		 * "prevaddr" is the last member of the list; append
475 		 * this member to it.
476 		 */
477 		prevaddr->next = curaddr;
478 	}
479 
480 	return (0);
481 }
482 
483 int
pcap_add_if(pcap_if_t ** devlist,const char * name,u_int flags,const char * description,char * errbuf)484 pcap_add_if(pcap_if_t **devlist, const char *name, u_int flags,
485     const char *description, char *errbuf)
486 {
487 	pcap_if_t *curdev;
488 
489 	return (add_or_find_if(&curdev, devlist, name, flags, description,
490 	    errbuf));
491 }
492 
493 
494 /*
495  * Free a list of interfaces.
496  */
497 void
pcap_freealldevs(pcap_if_t * alldevs)498 pcap_freealldevs(pcap_if_t *alldevs)
499 {
500 	pcap_if_t *curdev, *nextdev;
501 	pcap_addr_t *curaddr, *nextaddr;
502 
503 	for (curdev = alldevs; curdev != NULL; curdev = nextdev) {
504 		nextdev = curdev->next;
505 
506 		/*
507 		 * Free all addresses.
508 		 */
509 		for (curaddr = curdev->addresses; curaddr != NULL; curaddr = nextaddr) {
510 			nextaddr = curaddr->next;
511 			if (curaddr->addr)
512 				free(curaddr->addr);
513 			if (curaddr->netmask)
514 				free(curaddr->netmask);
515 			if (curaddr->broadaddr)
516 				free(curaddr->broadaddr);
517 			if (curaddr->dstaddr)
518 				free(curaddr->dstaddr);
519 			free(curaddr);
520 		}
521 
522 		/*
523 		 * Free the name string.
524 		 */
525 		free(curdev->name);
526 
527 		/*
528 		 * Free the description string, if any.
529 		 */
530 		if (curdev->description != NULL)
531 			free(curdev->description);
532 
533 		/*
534 		 * Free the interface.
535 		 */
536 		free(curdev);
537 	}
538 }
539 
540 #if !defined(WIN32) && !defined(MSDOS)
541 
542 /*
543  * Return the name of a network interface attached to the system, or NULL
544  * if none can be found.  The interface must be configured up; the
545  * lowest unit number is preferred; loopback is ignored.
546  */
547 char *
pcap_lookupdev(errbuf)548 pcap_lookupdev(errbuf)
549 	register char *errbuf;
550 {
551 	pcap_if_t *alldevs;
552 /* for old BSD systems, including bsdi3 */
553 #ifndef IF_NAMESIZE
554 #define IF_NAMESIZE IFNAMSIZ
555 #endif
556 	static char device[IF_NAMESIZE + 1];
557 	char *ret;
558 
559 	if (pcap_findalldevs(&alldevs, errbuf) == -1)
560 		return (NULL);
561 
562 	if (alldevs == NULL || (alldevs->flags & PCAP_IF_LOOPBACK)) {
563 		/*
564 		 * There are no devices on the list, or the first device
565 		 * on the list is a loopback device, which means there
566 		 * are no non-loopback devices on the list.  This means
567 		 * we can't return any device.
568 		 *
569 		 * XXX - why not return a loopback device?  If we can't
570 		 * capture on it, it won't be on the list, and if it's
571 		 * on the list, there aren't any non-loopback devices,
572 		 * so why not just supply it as the default device?
573 		 */
574 		(void)strlcpy(errbuf, "no suitable device found",
575 		    PCAP_ERRBUF_SIZE);
576 		ret = NULL;
577 	} else {
578 		/*
579 		 * Return the name of the first device on the list.
580 		 */
581 		(void)strlcpy(device, alldevs->name, sizeof(device));
582 		ret = device;
583 	}
584 
585 	pcap_freealldevs(alldevs);
586 	return (ret);
587 }
588 
589 int
pcap_lookupnet(device,netp,maskp,errbuf)590 pcap_lookupnet(device, netp, maskp, errbuf)
591 	register const char *device;
592 	register bpf_u_int32 *netp, *maskp;
593 	register char *errbuf;
594 {
595 	register int fd;
596 	register struct sockaddr_in *sin4;
597 	struct ifreq ifr;
598 
599 	/*
600 	 * The pseudo-device "any" listens on all interfaces and therefore
601 	 * has the network address and -mask "0.0.0.0" therefore catching
602 	 * all traffic. Using NULL for the interface is the same as "any".
603 	 */
604 	if (!device || strcmp(device, "any") == 0
605 #ifdef HAVE_DAG_API
606 	    || strstr(device, "dag") != NULL
607 #endif
608 #ifdef HAVE_SEPTEL_API
609 	    || strstr(device, "septel") != NULL
610 #endif
611 	    ) {
612 		*netp = *maskp = 0;
613 		return 0;
614 	}
615 
616 	fd = socket(AF_INET, SOCK_DGRAM, 0);
617 	if (fd < 0) {
618 		(void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
619 		    pcap_strerror(errno));
620 		return (-1);
621 	}
622 	memset(&ifr, 0, sizeof(ifr));
623 #ifdef linux
624 	/* XXX Work around Linux kernel bug */
625 	ifr.ifr_addr.sa_family = AF_INET;
626 #endif
627 	(void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
628 	if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
629 		if (errno == EADDRNOTAVAIL) {
630 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
631 			    "%s: no IPv4 address assigned", device);
632 		} else {
633 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
634 			    "SIOCGIFADDR: %s: %s",
635 			    device, pcap_strerror(errno));
636 		}
637 		(void)close(fd);
638 		return (-1);
639 	}
640 	sin4 = (struct sockaddr_in *)&ifr.ifr_addr;
641 	*netp = sin4->sin_addr.s_addr;
642 	if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
643 		(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
644 		    "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno));
645 		(void)close(fd);
646 		return (-1);
647 	}
648 	(void)close(fd);
649 	*maskp = sin4->sin_addr.s_addr;
650 	if (*maskp == 0) {
651 		if (IN_CLASSA(*netp))
652 			*maskp = IN_CLASSA_NET;
653 		else if (IN_CLASSB(*netp))
654 			*maskp = IN_CLASSB_NET;
655 		else if (IN_CLASSC(*netp))
656 			*maskp = IN_CLASSC_NET;
657 		else {
658 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
659 			    "inet class for 0x%x unknown", *netp);
660 			return (-1);
661 		}
662 	}
663 	*netp &= *maskp;
664 	return (0);
665 }
666 
667 #elif defined(WIN32)
668 
669 /*
670  * Return the name of a network interface attached to the system, or NULL
671  * if none can be found.  The interface must be configured up; the
672  * lowest unit number is preferred; loopback is ignored.
673  */
674 char *
pcap_lookupdev(errbuf)675 pcap_lookupdev(errbuf)
676 	register char *errbuf;
677 {
678 	DWORD dwVersion;
679 	DWORD dwWindowsMajorVersion;
680 	dwVersion = GetVersion();	/* get the OS version */
681 	dwWindowsMajorVersion = (DWORD)(LOBYTE(LOWORD(dwVersion)));
682 
683 	if (dwVersion >= 0x80000000 && dwWindowsMajorVersion >= 4) {
684 		/*
685 		 * Windows 95, 98, ME.
686 		 */
687 		ULONG NameLength = 8192;
688 		static char AdaptersName[8192];
689 
690 		if (PacketGetAdapterNames(AdaptersName,&NameLength) )
691 			return (AdaptersName);
692 		else
693 			return NULL;
694 	} else {
695 		/*
696 		 * Windows NT (NT 4.0, W2K, WXP). Convert the names to UNICODE for backward compatibility
697 		 */
698 		ULONG NameLength = 8192;
699 		static WCHAR AdaptersName[8192];
700 		char *tAstr;
701 		WCHAR *tUstr;
702 		WCHAR *TAdaptersName = (WCHAR*)malloc(8192 * sizeof(WCHAR));
703 		int NAdapts = 0;
704 
705 		if(TAdaptersName == NULL)
706 		{
707 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "memory allocation failure");
708 			return NULL;
709 		}
710 
711 		if ( !PacketGetAdapterNames((PTSTR)TAdaptersName,&NameLength) )
712 		{
713 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
714 				"PacketGetAdapterNames: %s",
715 				pcap_win32strerror());
716 			free(TAdaptersName);
717 			return NULL;
718 		}
719 
720 
721 		tAstr = (char*)TAdaptersName;
722 		tUstr = (WCHAR*)AdaptersName;
723 
724 		/*
725 		 * Convert and copy the device names
726 		 */
727 		while(sscanf(tAstr, "%S", tUstr) > 0)
728 		{
729 			tAstr += strlen(tAstr) + 1;
730 			tUstr += wcslen(tUstr) + 1;
731 			NAdapts ++;
732 		}
733 
734 		tAstr++;
735 		*tUstr = 0;
736 		tUstr++;
737 
738 		/*
739 		 * Copy the descriptions
740 		 */
741 		while(NAdapts--)
742 		{
743 			strcpy((char*)tUstr, tAstr);
744 			(char*)tUstr += strlen(tAstr) + 1;;
745 			tAstr += strlen(tAstr) + 1;
746 		}
747 
748 		free(TAdaptersName);
749 		return (char *)(AdaptersName);
750 	}
751 }
752 
753 
754 int
pcap_lookupnet(device,netp,maskp,errbuf)755 pcap_lookupnet(device, netp, maskp, errbuf)
756 	register const char *device;
757 	register bpf_u_int32 *netp, *maskp;
758 	register char *errbuf;
759 {
760 	/*
761 	 * We need only the first IPv4 address, so we must scan the array returned by PacketGetNetInfo()
762 	 * in order to skip non IPv4 (i.e. IPv6 addresses)
763 	 */
764 	npf_if_addr if_addrs[MAX_NETWORK_ADDRESSES];
765 	LONG if_addr_size = 1;
766 	struct sockaddr_in *t_addr;
767 	unsigned int i;
768 
769 	if (!PacketGetNetInfoEx((void *)device, if_addrs, &if_addr_size)) {
770 		*netp = *maskp = 0;
771 		return (0);
772 	}
773 
774 	for(i=0; i<MAX_NETWORK_ADDRESSES; i++)
775 	{
776 		if(if_addrs[i].IPAddress.ss_family == AF_INET)
777 		{
778 			t_addr = (struct sockaddr_in *) &(if_addrs[i].IPAddress);
779 			*netp = t_addr->sin_addr.S_un.S_addr;
780 			t_addr = (struct sockaddr_in *) &(if_addrs[i].SubnetMask);
781 			*maskp = t_addr->sin_addr.S_un.S_addr;
782 
783 			*netp &= *maskp;
784 			return (0);
785 		}
786 
787 	}
788 
789 	*netp = *maskp = 0;
790 	return (0);
791 }
792 
793 #endif /* !WIN32 && !MSDOS */
794