xref: /freebsd/contrib/libpcap/pcap.c (revision 2b743a9e9ddc6736208dc8ca1ce06ce64ad20a19)
1 /*
2  * Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the Computer Systems
16  *	Engineering Group at Lawrence Berkeley Laboratory.
17  * 4. Neither the name of the University nor of the Laboratory may be used
18  *    to endorse or promote products derived from this software without
19  *    specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 static const char rcsid[] _U_ =
36     "@(#) $Header: /tcpdump/master/libpcap/pcap.c,v 1.88.2.8 2005/08/13 22:29:46 hannes Exp $ (LBL)";
37 #endif
38 
39 #ifdef HAVE_CONFIG_H
40 #include "config.h"
41 #endif
42 
43 #ifdef WIN32
44 #include <pcap-stdinc.h>
45 #else /* WIN32 */
46 #include <sys/types.h>
47 #endif /* WIN32 */
48 
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #if !defined(_MSC_VER) && !defined(__BORLANDC__)
53 #include <unistd.h>
54 #endif
55 #include <fcntl.h>
56 #include <errno.h>
57 
58 #ifdef HAVE_OS_PROTO_H
59 #include "os-proto.h"
60 #endif
61 
62 #ifdef MSDOS
63 #include "pcap-dos.h"
64 #endif
65 
66 #include "pcap-int.h"
67 
68 #ifdef HAVE_DAG_API
69 #include <dagnew.h>
70 #include <dagapi.h>
71 #endif
72 
73 int
74 pcap_dispatch(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
75 {
76 
77 	return p->read_op(p, cnt, callback, user);
78 }
79 
80 /*
81  * XXX - is this necessary?
82  */
83 int
84 pcap_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
85 {
86 
87 	return p->read_op(p, cnt, callback, user);
88 }
89 
90 int
91 pcap_loop(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
92 {
93 	register int n;
94 
95 	for (;;) {
96 		if (p->sf.rfile != NULL) {
97 			/*
98 			 * 0 means EOF, so don't loop if we get 0.
99 			 */
100 			n = pcap_offline_read(p, cnt, callback, user);
101 		} else {
102 			/*
103 			 * XXX keep reading until we get something
104 			 * (or an error occurs)
105 			 */
106 			do {
107 				n = p->read_op(p, cnt, callback, user);
108 			} while (n == 0);
109 		}
110 		if (n <= 0)
111 			return (n);
112 		if (cnt > 0) {
113 			cnt -= n;
114 			if (cnt <= 0)
115 				return (0);
116 		}
117 	}
118 }
119 
120 struct singleton {
121 	struct pcap_pkthdr *hdr;
122 	const u_char *pkt;
123 };
124 
125 
126 static void
127 pcap_oneshot(u_char *userData, const struct pcap_pkthdr *h, const u_char *pkt)
128 {
129 	struct singleton *sp = (struct singleton *)userData;
130 	*sp->hdr = *h;
131 	sp->pkt = pkt;
132 }
133 
134 const u_char *
135 pcap_next(pcap_t *p, struct pcap_pkthdr *h)
136 {
137 	struct singleton s;
138 
139 	s.hdr = h;
140 	if (pcap_dispatch(p, 1, pcap_oneshot, (u_char*)&s) <= 0)
141 		return (0);
142 	return (s.pkt);
143 }
144 
145 struct pkt_for_fakecallback {
146 	struct pcap_pkthdr *hdr;
147 	const u_char **pkt;
148 };
149 
150 static void
151 pcap_fakecallback(u_char *userData, const struct pcap_pkthdr *h,
152     const u_char *pkt)
153 {
154 	struct pkt_for_fakecallback *sp = (struct pkt_for_fakecallback *)userData;
155 
156 	*sp->hdr = *h;
157 	*sp->pkt = pkt;
158 }
159 
160 int
161 pcap_next_ex(pcap_t *p, struct pcap_pkthdr **pkt_header,
162     const u_char **pkt_data)
163 {
164 	struct pkt_for_fakecallback s;
165 
166 	s.hdr = &p->pcap_header;
167 	s.pkt = pkt_data;
168 
169 	/* Saves a pointer to the packet headers */
170 	*pkt_header= &p->pcap_header;
171 
172 	if (p->sf.rfile != NULL) {
173 		int status;
174 
175 		/* We are on an offline capture */
176 		status = pcap_offline_read(p, 1, pcap_fakecallback,
177 		    (u_char *)&s);
178 
179 		/*
180 		 * Return codes for pcap_offline_read() are:
181 		 *   -  0: EOF
182 		 *   - -1: error
183 		 *   - >1: OK
184 		 * The first one ('0') conflicts with the return code of
185 		 * 0 from pcap_read() meaning "no packets arrived before
186 		 * the timeout expired", so we map it to -2 so you can
187 		 * distinguish between an EOF from a savefile and a
188 		 * "no packets arrived before the timeout expired, try
189 		 * again" from a live capture.
190 		 */
191 		if (status == 0)
192 			return (-2);
193 		else
194 			return (status);
195 	}
196 
197 	/*
198 	 * Return codes for pcap_read() are:
199 	 *   -  0: timeout
200 	 *   - -1: error
201 	 *   - -2: loop was broken out of with pcap_breakloop()
202 	 *   - >1: OK
203 	 * The first one ('0') conflicts with the return code of 0 from
204 	 * pcap_offline_read() meaning "end of file".
205 	*/
206 	return (p->read_op(p, 1, pcap_fakecallback, (u_char *)&s));
207 }
208 
209 /*
210  * Force the loop in "pcap_read()" or "pcap_read_offline()" to terminate.
211  */
212 void
213 pcap_breakloop(pcap_t *p)
214 {
215 	p->break_loop = 1;
216 }
217 
218 int
219 pcap_datalink(pcap_t *p)
220 {
221 	return (p->linktype);
222 }
223 
224 int
225 pcap_list_datalinks(pcap_t *p, int **dlt_buffer)
226 {
227 	if (p->dlt_count == 0) {
228 		/*
229 		 * We couldn't fetch the list of DLTs, which means
230 		 * this platform doesn't support changing the
231 		 * DLT for an interface.  Return a list of DLTs
232 		 * containing only the DLT this device supports.
233 		 */
234 		*dlt_buffer = (int*)malloc(sizeof(**dlt_buffer));
235 		if (*dlt_buffer == NULL) {
236 			(void)snprintf(p->errbuf, sizeof(p->errbuf),
237 			    "malloc: %s", pcap_strerror(errno));
238 			return (-1);
239 		}
240 		**dlt_buffer = p->linktype;
241 		return (1);
242 	} else {
243 		*dlt_buffer = (int*)malloc(sizeof(**dlt_buffer) * p->dlt_count);
244 		if (*dlt_buffer == NULL) {
245 			(void)snprintf(p->errbuf, sizeof(p->errbuf),
246 			    "malloc: %s", pcap_strerror(errno));
247 			return (-1);
248 		}
249 		(void)memcpy(*dlt_buffer, p->dlt_list,
250 		    sizeof(**dlt_buffer) * p->dlt_count);
251 		return (p->dlt_count);
252 	}
253 }
254 
255 int
256 pcap_set_datalink(pcap_t *p, int dlt)
257 {
258 	int i;
259 	const char *dlt_name;
260 
261 	if (p->dlt_count == 0 || p->set_datalink_op == NULL) {
262 		/*
263 		 * We couldn't fetch the list of DLTs, or we don't
264 		 * have a "set datalink" operation, which means
265 		 * this platform doesn't support changing the
266 		 * DLT for an interface.  Check whether the new
267 		 * DLT is the one this interface supports.
268 		 */
269 		if (p->linktype != dlt)
270 			goto unsupported;
271 
272 		/*
273 		 * It is, so there's nothing we need to do here.
274 		 */
275 		return (0);
276 	}
277 	for (i = 0; i < p->dlt_count; i++)
278 		if (p->dlt_list[i] == dlt)
279 			break;
280 	if (i >= p->dlt_count)
281 		goto unsupported;
282 	if (p->dlt_count == 2 && p->dlt_list[0] == DLT_EN10MB &&
283 	    dlt == DLT_DOCSIS) {
284 		/*
285 		 * This is presumably an Ethernet device, as the first
286 		 * link-layer type it offers is DLT_EN10MB, and the only
287 		 * other type it offers is DLT_DOCSIS.  That means that
288 		 * we can't tell the driver to supply DOCSIS link-layer
289 		 * headers - we're just pretending that's what we're
290 		 * getting, as, presumably, we're capturing on a dedicated
291 		 * link to a Cisco Cable Modem Termination System, and
292 		 * it's putting raw DOCSIS frames on the wire inside low-level
293 		 * Ethernet framing.
294 		 */
295 		p->linktype = dlt;
296 		return (0);
297 	}
298 	if (p->set_datalink_op(p, dlt) == -1)
299 		return (-1);
300 	p->linktype = dlt;
301 	return (0);
302 
303 unsupported:
304 	dlt_name = pcap_datalink_val_to_name(dlt);
305 	if (dlt_name != NULL) {
306 		(void) snprintf(p->errbuf, sizeof(p->errbuf),
307 		    "%s is not one of the DLTs supported by this device",
308 		    dlt_name);
309 	} else {
310 		(void) snprintf(p->errbuf, sizeof(p->errbuf),
311 		    "DLT %d is not one of the DLTs supported by this device",
312 		    dlt);
313 	}
314 	return (-1);
315 }
316 
317 struct dlt_choice {
318 	const char *name;
319 	const char *description;
320 	int	dlt;
321 };
322 
323 #define DLT_CHOICE(code, description) { #code, description, code }
324 #define DLT_CHOICE_SENTINEL { NULL, NULL, 0 }
325 
326 static struct dlt_choice dlt_choices[] = {
327 	DLT_CHOICE(DLT_NULL, "BSD loopback"),
328 	DLT_CHOICE(DLT_EN10MB, "Ethernet"),
329 	DLT_CHOICE(DLT_IEEE802, "Token ring"),
330 	DLT_CHOICE(DLT_ARCNET, "ARCNET"),
331 	DLT_CHOICE(DLT_SLIP, "SLIP"),
332 	DLT_CHOICE(DLT_PPP, "PPP"),
333 	DLT_CHOICE(DLT_FDDI, "FDDI"),
334 	DLT_CHOICE(DLT_ATM_RFC1483, "RFC 1483 LLC-encapsulated ATM"),
335 	DLT_CHOICE(DLT_RAW, "Raw IP"),
336 	DLT_CHOICE(DLT_SLIP_BSDOS, "BSD/OS SLIP"),
337 	DLT_CHOICE(DLT_PPP_BSDOS, "BSD/OS PPP"),
338 	DLT_CHOICE(DLT_ATM_CLIP, "Linux Classical IP-over-ATM"),
339 	DLT_CHOICE(DLT_PPP_SERIAL, "PPP over serial"),
340 	DLT_CHOICE(DLT_PPP_ETHER, "PPPoE"),
341 	DLT_CHOICE(DLT_C_HDLC, "Cisco HDLC"),
342 	DLT_CHOICE(DLT_IEEE802_11, "802.11"),
343 	DLT_CHOICE(DLT_FRELAY, "Frame Relay"),
344 	DLT_CHOICE(DLT_LOOP, "OpenBSD loopback"),
345 	DLT_CHOICE(DLT_ENC, "OpenBSD encapsulated IP"),
346 	DLT_CHOICE(DLT_LINUX_SLL, "Linux cooked"),
347 	DLT_CHOICE(DLT_LTALK, "Localtalk"),
348 	DLT_CHOICE(DLT_PFLOG, "OpenBSD pflog file"),
349 	DLT_CHOICE(DLT_PRISM_HEADER, "802.11 plus Prism header"),
350 	DLT_CHOICE(DLT_IP_OVER_FC, "RFC 2625 IP-over-Fibre Channel"),
351 	DLT_CHOICE(DLT_SUNATM, "Sun raw ATM"),
352 	DLT_CHOICE(DLT_IEEE802_11_RADIO, "802.11 plus BSD radio information header"),
353 	DLT_CHOICE(DLT_APPLE_IP_OVER_IEEE1394, "Apple IP-over-IEEE 1394"),
354 	DLT_CHOICE(DLT_ARCNET_LINUX, "Linux ARCNET"),
355 	DLT_CHOICE(DLT_DOCSIS, "DOCSIS"),
356 	DLT_CHOICE(DLT_LINUX_IRDA, "Linux IrDA"),
357 	DLT_CHOICE(DLT_IEEE802_11_RADIO_AVS, "802.11 plus AVS radio information header"),
358         DLT_CHOICE(DLT_SYMANTEC_FIREWALL, "Symantec Firewall"),
359         DLT_CHOICE(DLT_JUNIPER_ATM1, "Juniper ATM1 PIC"),
360         DLT_CHOICE(DLT_JUNIPER_ATM2, "Juniper ATM2 PIC"),
361         DLT_CHOICE(DLT_JUNIPER_MLPPP, "Juniper Multi-Link PPP"),
362  	DLT_CHOICE(DLT_PPP_PPPD, "PPP for pppd, with direction flag"),
363  	DLT_CHOICE(DLT_JUNIPER_PPPOE, "Juniper PPPoE"),
364  	DLT_CHOICE(DLT_JUNIPER_PPPOE_ATM, "Juniper PPPoE/ATM"),
365  	DLT_CHOICE(DLT_GPRS_LLC, "GPRS LLC"),
366  	DLT_CHOICE(DLT_GPF_T, "GPF-T"),
367  	DLT_CHOICE(DLT_GPF_F, "GPF-F"),
368  	DLT_CHOICE(DLT_JUNIPER_PIC_PEER, "Juniper PIC Peer"),
369  	DLT_CHOICE(DLT_JUNIPER_MLFR, "Juniper Multi-Link Frame Relay"),
370 	DLT_CHOICE(DLT_ERF_ETH,	"Ethernet with Endace ERF header"),
371 	DLT_CHOICE(DLT_ERF_POS, "Packet-over-SONET with Endace ERF header"),
372         DLT_CHOICE(DLT_JUNIPER_GGSN, "Juniper GGSN PIC"),
373         DLT_CHOICE(DLT_JUNIPER_ES, "Juniper Encryption Services PIC"),
374         DLT_CHOICE(DLT_JUNIPER_MONITOR, "Juniper Passive Monitor PIC"),
375         DLT_CHOICE(DLT_JUNIPER_SERVICES, "Juniper Advanced Services PIC"),
376  	DLT_CHOICE(DLT_JUNIPER_MFR, "Juniper FRF.16 Frame Relay"),
377  	DLT_CHOICE(DLT_JUNIPER_ETHER, "Juniper Ethernet"),
378  	DLT_CHOICE(DLT_JUNIPER_PPP, "Juniper PPP"),
379  	DLT_CHOICE(DLT_JUNIPER_FRELAY, "Juniper Frame Relay"),
380  	DLT_CHOICE(DLT_JUNIPER_CHDLC, "Juniper C-HDLC"),
381 	DLT_CHOICE_SENTINEL
382 };
383 
384 /*
385  * This array is designed for mapping upper and lower case letter
386  * together for a case independent comparison.  The mappings are
387  * based upon ascii character sequences.
388  */
389 static const u_char charmap[] = {
390 	(u_char)'\000', (u_char)'\001', (u_char)'\002', (u_char)'\003',
391 	(u_char)'\004', (u_char)'\005', (u_char)'\006', (u_char)'\007',
392 	(u_char)'\010', (u_char)'\011', (u_char)'\012', (u_char)'\013',
393 	(u_char)'\014', (u_char)'\015', (u_char)'\016', (u_char)'\017',
394 	(u_char)'\020', (u_char)'\021', (u_char)'\022', (u_char)'\023',
395 	(u_char)'\024', (u_char)'\025', (u_char)'\026', (u_char)'\027',
396 	(u_char)'\030', (u_char)'\031', (u_char)'\032', (u_char)'\033',
397 	(u_char)'\034', (u_char)'\035', (u_char)'\036', (u_char)'\037',
398 	(u_char)'\040', (u_char)'\041', (u_char)'\042', (u_char)'\043',
399 	(u_char)'\044', (u_char)'\045', (u_char)'\046', (u_char)'\047',
400 	(u_char)'\050', (u_char)'\051', (u_char)'\052', (u_char)'\053',
401 	(u_char)'\054', (u_char)'\055', (u_char)'\056', (u_char)'\057',
402 	(u_char)'\060', (u_char)'\061', (u_char)'\062', (u_char)'\063',
403 	(u_char)'\064', (u_char)'\065', (u_char)'\066', (u_char)'\067',
404 	(u_char)'\070', (u_char)'\071', (u_char)'\072', (u_char)'\073',
405 	(u_char)'\074', (u_char)'\075', (u_char)'\076', (u_char)'\077',
406 	(u_char)'\100', (u_char)'\141', (u_char)'\142', (u_char)'\143',
407 	(u_char)'\144', (u_char)'\145', (u_char)'\146', (u_char)'\147',
408 	(u_char)'\150', (u_char)'\151', (u_char)'\152', (u_char)'\153',
409 	(u_char)'\154', (u_char)'\155', (u_char)'\156', (u_char)'\157',
410 	(u_char)'\160', (u_char)'\161', (u_char)'\162', (u_char)'\163',
411 	(u_char)'\164', (u_char)'\165', (u_char)'\166', (u_char)'\167',
412 	(u_char)'\170', (u_char)'\171', (u_char)'\172', (u_char)'\133',
413 	(u_char)'\134', (u_char)'\135', (u_char)'\136', (u_char)'\137',
414 	(u_char)'\140', (u_char)'\141', (u_char)'\142', (u_char)'\143',
415 	(u_char)'\144', (u_char)'\145', (u_char)'\146', (u_char)'\147',
416 	(u_char)'\150', (u_char)'\151', (u_char)'\152', (u_char)'\153',
417 	(u_char)'\154', (u_char)'\155', (u_char)'\156', (u_char)'\157',
418 	(u_char)'\160', (u_char)'\161', (u_char)'\162', (u_char)'\163',
419 	(u_char)'\164', (u_char)'\165', (u_char)'\166', (u_char)'\167',
420 	(u_char)'\170', (u_char)'\171', (u_char)'\172', (u_char)'\173',
421 	(u_char)'\174', (u_char)'\175', (u_char)'\176', (u_char)'\177',
422 	(u_char)'\200', (u_char)'\201', (u_char)'\202', (u_char)'\203',
423 	(u_char)'\204', (u_char)'\205', (u_char)'\206', (u_char)'\207',
424 	(u_char)'\210', (u_char)'\211', (u_char)'\212', (u_char)'\213',
425 	(u_char)'\214', (u_char)'\215', (u_char)'\216', (u_char)'\217',
426 	(u_char)'\220', (u_char)'\221', (u_char)'\222', (u_char)'\223',
427 	(u_char)'\224', (u_char)'\225', (u_char)'\226', (u_char)'\227',
428 	(u_char)'\230', (u_char)'\231', (u_char)'\232', (u_char)'\233',
429 	(u_char)'\234', (u_char)'\235', (u_char)'\236', (u_char)'\237',
430 	(u_char)'\240', (u_char)'\241', (u_char)'\242', (u_char)'\243',
431 	(u_char)'\244', (u_char)'\245', (u_char)'\246', (u_char)'\247',
432 	(u_char)'\250', (u_char)'\251', (u_char)'\252', (u_char)'\253',
433 	(u_char)'\254', (u_char)'\255', (u_char)'\256', (u_char)'\257',
434 	(u_char)'\260', (u_char)'\261', (u_char)'\262', (u_char)'\263',
435 	(u_char)'\264', (u_char)'\265', (u_char)'\266', (u_char)'\267',
436 	(u_char)'\270', (u_char)'\271', (u_char)'\272', (u_char)'\273',
437 	(u_char)'\274', (u_char)'\275', (u_char)'\276', (u_char)'\277',
438 	(u_char)'\300', (u_char)'\341', (u_char)'\342', (u_char)'\343',
439 	(u_char)'\344', (u_char)'\345', (u_char)'\346', (u_char)'\347',
440 	(u_char)'\350', (u_char)'\351', (u_char)'\352', (u_char)'\353',
441 	(u_char)'\354', (u_char)'\355', (u_char)'\356', (u_char)'\357',
442 	(u_char)'\360', (u_char)'\361', (u_char)'\362', (u_char)'\363',
443 	(u_char)'\364', (u_char)'\365', (u_char)'\366', (u_char)'\367',
444 	(u_char)'\370', (u_char)'\371', (u_char)'\372', (u_char)'\333',
445 	(u_char)'\334', (u_char)'\335', (u_char)'\336', (u_char)'\337',
446 	(u_char)'\340', (u_char)'\341', (u_char)'\342', (u_char)'\343',
447 	(u_char)'\344', (u_char)'\345', (u_char)'\346', (u_char)'\347',
448 	(u_char)'\350', (u_char)'\351', (u_char)'\352', (u_char)'\353',
449 	(u_char)'\354', (u_char)'\355', (u_char)'\356', (u_char)'\357',
450 	(u_char)'\360', (u_char)'\361', (u_char)'\362', (u_char)'\363',
451 	(u_char)'\364', (u_char)'\365', (u_char)'\366', (u_char)'\367',
452 	(u_char)'\370', (u_char)'\371', (u_char)'\372', (u_char)'\373',
453 	(u_char)'\374', (u_char)'\375', (u_char)'\376', (u_char)'\377',
454 };
455 
456 int
457 pcap_strcasecmp(const char *s1, const char *s2)
458 {
459 	register const u_char	*cm = charmap,
460 				*us1 = (u_char *)s1,
461 				*us2 = (u_char *)s2;
462 
463 	while (cm[*us1] == cm[*us2++])
464 		if (*us1++ == '\0')
465 			return(0);
466 	return (cm[*us1] - cm[*--us2]);
467 }
468 
469 int
470 pcap_datalink_name_to_val(const char *name)
471 {
472 	int i;
473 
474 	for (i = 0; dlt_choices[i].name != NULL; i++) {
475 		if (pcap_strcasecmp(dlt_choices[i].name + sizeof("DLT_") - 1,
476 		    name) == 0)
477 			return (dlt_choices[i].dlt);
478 	}
479 	return (-1);
480 }
481 
482 const char *
483 pcap_datalink_val_to_name(int dlt)
484 {
485 	int i;
486 
487 	for (i = 0; dlt_choices[i].name != NULL; i++) {
488 		if (dlt_choices[i].dlt == dlt)
489 			return (dlt_choices[i].name + sizeof("DLT_") - 1);
490 	}
491 	return (NULL);
492 }
493 
494 const char *
495 pcap_datalink_val_to_description(int dlt)
496 {
497 	int i;
498 
499 	for (i = 0; dlt_choices[i].name != NULL; i++) {
500 		if (dlt_choices[i].dlt == dlt)
501 			return (dlt_choices[i].description);
502 	}
503 	return (NULL);
504 }
505 
506 int
507 pcap_snapshot(pcap_t *p)
508 {
509 	return (p->snapshot);
510 }
511 
512 int
513 pcap_is_swapped(pcap_t *p)
514 {
515 	return (p->sf.swapped);
516 }
517 
518 int
519 pcap_major_version(pcap_t *p)
520 {
521 	return (p->sf.version_major);
522 }
523 
524 int
525 pcap_minor_version(pcap_t *p)
526 {
527 	return (p->sf.version_minor);
528 }
529 
530 FILE *
531 pcap_file(pcap_t *p)
532 {
533 	return (p->sf.rfile);
534 }
535 
536 int
537 pcap_fileno(pcap_t *p)
538 {
539 #ifndef WIN32
540 	return (p->fd);
541 #else
542 	if (p->adapter != NULL)
543 		return ((int)(DWORD)p->adapter->hFile);
544 	else
545 		return (-1);
546 #endif
547 }
548 
549 #if !defined(WIN32) && !defined(MSDOS)
550 int
551 pcap_get_selectable_fd(pcap_t *p)
552 {
553 	return (p->selectable_fd);
554 }
555 #endif
556 
557 void
558 pcap_perror(pcap_t *p, char *prefix)
559 {
560 	fprintf(stderr, "%s: %s\n", prefix, p->errbuf);
561 }
562 
563 char *
564 pcap_geterr(pcap_t *p)
565 {
566 	return (p->errbuf);
567 }
568 
569 int
570 pcap_getnonblock(pcap_t *p, char *errbuf)
571 {
572 	return p->getnonblock_op(p, errbuf);
573 }
574 
575 /*
576  * Get the current non-blocking mode setting, under the assumption that
577  * it's just the standard POSIX non-blocking flag.
578  *
579  * We don't look at "p->nonblock", in case somebody tweaked the FD
580  * directly.
581  */
582 #if !defined(WIN32) && !defined(MSDOS)
583 int
584 pcap_getnonblock_fd(pcap_t *p, char *errbuf)
585 {
586 	int fdflags;
587 
588 	fdflags = fcntl(p->fd, F_GETFL, 0);
589 	if (fdflags == -1) {
590 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "F_GETFL: %s",
591 		    pcap_strerror(errno));
592 		return (-1);
593 	}
594 	if (fdflags & O_NONBLOCK)
595 		return (1);
596 	else
597 		return (0);
598 }
599 #endif
600 
601 int
602 pcap_setnonblock(pcap_t *p, int nonblock, char *errbuf)
603 {
604 	return p->setnonblock_op(p, nonblock, errbuf);
605 }
606 
607 #if !defined(WIN32) && !defined(MSDOS)
608 /*
609  * Set non-blocking mode, under the assumption that it's just the
610  * standard POSIX non-blocking flag.  (This can be called by the
611  * per-platform non-blocking-mode routine if that routine also
612  * needs to do some additional work.)
613  */
614 int
615 pcap_setnonblock_fd(pcap_t *p, int nonblock, char *errbuf)
616 {
617 	int fdflags;
618 
619 	fdflags = fcntl(p->fd, F_GETFL, 0);
620 	if (fdflags == -1) {
621 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "F_GETFL: %s",
622 		    pcap_strerror(errno));
623 		return (-1);
624 	}
625 	if (nonblock)
626 		fdflags |= O_NONBLOCK;
627 	else
628 		fdflags &= ~O_NONBLOCK;
629 	if (fcntl(p->fd, F_SETFL, fdflags) == -1) {
630 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "F_SETFL: %s",
631 		    pcap_strerror(errno));
632 		return (-1);
633 	}
634 	return (0);
635 }
636 #endif
637 
638 #ifdef WIN32
639 /*
640  * Generate a string for the last Win32-specific error (i.e. an error generated when
641  * calling a Win32 API).
642  * For errors occurred during standard C calls, we still use pcap_strerror()
643  */
644 char *
645 pcap_win32strerror(void)
646 {
647 	DWORD error;
648 	static char errbuf[PCAP_ERRBUF_SIZE+1];
649 	int errlen;
650 	char *p;
651 
652 	error = GetLastError();
653 	FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, error, 0, errbuf,
654 	    PCAP_ERRBUF_SIZE, NULL);
655 
656 	/*
657 	 * "FormatMessage()" "helpfully" sticks CR/LF at the end of the
658 	 * message.  Get rid of it.
659 	 */
660 	errlen = strlen(errbuf);
661 	if (errlen >= 2) {
662 		errbuf[errlen - 1] = '\0';
663 		errbuf[errlen - 2] = '\0';
664 	}
665 	p = strchr(errbuf, '\0');
666 	snprintf (p, sizeof(errbuf)-(p-errbuf), " (%lu)", error);
667 	return (errbuf);
668 }
669 #endif
670 
671 /*
672  * Not all systems have strerror().
673  */
674 char *
675 pcap_strerror(int errnum)
676 {
677 #ifdef HAVE_STRERROR
678 	return (strerror(errnum));
679 #else
680 	extern int sys_nerr;
681 	extern const char *const sys_errlist[];
682 	static char ebuf[20];
683 
684 	if ((unsigned int)errnum < sys_nerr)
685 		return ((char *)sys_errlist[errnum]);
686 	(void)snprintf(ebuf, sizeof ebuf, "Unknown error: %d", errnum);
687 	return(ebuf);
688 #endif
689 }
690 
691 int
692 pcap_setfilter(pcap_t *p, struct bpf_program *fp)
693 {
694 	return p->setfilter_op(p, fp);
695 }
696 
697 /*
698  * Set direction flag, which controls whether we accept only incoming
699  * packets, only outgoing packets, or both.
700  * Note that, depending on the platform, some or all direction arguments
701  * might not be supported.
702  */
703 int
704 pcap_setdirection(pcap_t *p, pcap_direction_t d)
705 {
706 	if (p->setdirection_op == NULL) {
707 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
708 		    "Setting direction is not implemented on this platform");
709 		return -1;
710 	} else
711 		return p->setdirection_op(p, d);
712 }
713 
714 int
715 pcap_stats(pcap_t *p, struct pcap_stat *ps)
716 {
717 	return p->stats_op(p, ps);
718 }
719 
720 static int
721 pcap_stats_dead(pcap_t *p, struct pcap_stat *ps _U_)
722 {
723 	snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
724 	    "Statistics aren't available from a pcap_open_dead pcap_t");
725 	return (-1);
726 }
727 
728 void
729 pcap_close_common(pcap_t *p)
730 {
731 	if (p->buffer != NULL)
732 		free(p->buffer);
733 #if !defined(WIN32) && !defined(MSDOS)
734 	if (p->fd >= 0)
735 		close(p->fd);
736 #endif
737 }
738 
739 static void
740 pcap_close_dead(pcap_t *p _U_)
741 {
742 	/* Nothing to do. */
743 }
744 
745 pcap_t *
746 pcap_open_dead(int linktype, int snaplen)
747 {
748 	pcap_t *p;
749 
750 	p = malloc(sizeof(*p));
751 	if (p == NULL)
752 		return NULL;
753 	memset (p, 0, sizeof(*p));
754 	p->snapshot = snaplen;
755 	p->linktype = linktype;
756 	p->stats_op = pcap_stats_dead;
757 	p->close_op = pcap_close_dead;
758 	return p;
759 }
760 
761 /*
762  * API compatible with WinPcap's "send a packet" routine - returns -1
763  * on error, 0 otherwise.
764  *
765  * XXX - what if we get a short write?
766  */
767 int
768 pcap_sendpacket(pcap_t *p, const u_char *buf, int size)
769 {
770 	if (p->inject_op(p, buf, size) == -1)
771 		return (-1);
772 	return (0);
773 }
774 
775 /*
776  * API compatible with OpenBSD's "send a packet" routine - returns -1 on
777  * error, number of bytes written otherwise.
778  */
779 int
780 pcap_inject(pcap_t *p, const void *buf, size_t size)
781 {
782 	return (p->inject_op(p, buf, size));
783 }
784 
785 void
786 pcap_close(pcap_t *p)
787 {
788 	p->close_op(p);
789 	if (p->dlt_list != NULL)
790 		free(p->dlt_list);
791 	pcap_freecode(&p->fcode);
792 	free(p);
793 }
794 
795 /*
796  * We make the version string static, and return a pointer to it, rather
797  * than exporting the version string directly.  On at least some UNIXes,
798  * if you import data from a shared library into an program, the data is
799  * bound into the program binary, so if the string in the version of the
800  * library with which the program was linked isn't the same as the
801  * string in the version of the library with which the program is being
802  * run, various undesirable things may happen (warnings, the string
803  * being the one from the version of the library with which the program
804  * was linked, or even weirder things, such as the string being the one
805  * from the library but being truncated).
806  */
807 #ifdef HAVE_VERSION_H
808 #include "version.h"
809 #else
810 static const char pcap_version_string[] = "libpcap version 0.9[.x]";
811 #endif
812 
813 #ifdef WIN32
814 /*
815  * XXX - it'd be nice if we could somehow generate the WinPcap and libpcap
816  * version numbers when building WinPcap.  (It'd be nice to do so for
817  * the packet.dll version number as well.)
818  */
819 static const char wpcap_version_string[] = "3.1";
820 static const char pcap_version_string_fmt[] =
821     "WinPcap version %s, based on %s";
822 static const char pcap_version_string_packet_dll_fmt[] =
823     "WinPcap version %s (packet.dll version %s), based on %s";
824 static char *full_pcap_version_string;
825 
826 const char *
827 pcap_lib_version(void)
828 {
829 	char *packet_version_string;
830 	size_t full_pcap_version_string_len;
831 
832 	if (full_pcap_version_string == NULL) {
833 		/*
834 		 * Generate the version string.
835 		 */
836 		packet_version_string = PacketGetVersion();
837 		if (strcmp(wpcap_version_string, packet_version_string) == 0) {
838 			/*
839 			 * WinPcap version string and packet.dll version
840 			 * string are the same; just report the WinPcap
841 			 * version.
842 			 */
843 			full_pcap_version_string_len =
844 			    (sizeof pcap_version_string_fmt - 4) +
845 			    strlen(wpcap_version_string) +
846 			    strlen(pcap_version_string);
847 			full_pcap_version_string =
848 			    malloc(full_pcap_version_string_len);
849 			sprintf(full_pcap_version_string,
850 			    pcap_version_string_fmt, wpcap_version_string,
851 			    pcap_version_string);
852 		} else {
853 			/*
854 			 * WinPcap version string and packet.dll version
855 			 * string are different; that shouldn't be the
856 			 * case (the two libraries should come from the
857 			 * same version of WinPcap), so we report both
858 			 * versions.
859 			 */
860 			full_pcap_version_string_len =
861 			    (sizeof pcap_version_string_packet_dll_fmt - 6) +
862 			    strlen(wpcap_version_string) +
863 			    strlen(packet_version_string) +
864 			    strlen(pcap_version_string);
865 			full_pcap_version_string = malloc(full_pcap_version_string_len);
866 
867 			sprintf(full_pcap_version_string,
868 			    pcap_version_string_packet_dll_fmt,
869 			    wpcap_version_string, packet_version_string,
870 			    pcap_version_string);
871 		}
872 	}
873 	return (full_pcap_version_string);
874 }
875 
876 #elif defined(MSDOS)
877 
878 static char *full_pcap_version_string;
879 
880 const char *
881 pcap_lib_version (void)
882 {
883 	char *packet_version_string;
884 	size_t full_pcap_version_string_len;
885 	static char dospfx[] = "DOS-";
886 
887 	if (full_pcap_version_string == NULL) {
888 		/*
889 		 * Generate the version string.
890 		 */
891 		full_pcap_version_string_len =
892 		    sizeof dospfx + strlen(pcap_version_string);
893 		full_pcap_version_string =
894 		    malloc(full_pcap_version_string_len);
895 		strcpy(full_pcap_version_string, dospfx);
896 		strcat(full_pcap_version_string, pcap_version_string);
897 	}
898 	return (full_pcap_version_string);
899 }
900 
901 #else /* UN*X */
902 
903 const char *
904 pcap_lib_version(void)
905 {
906 	return (pcap_version_string);
907 }
908 #endif
909