xref: /freebsd/contrib/libpcap/savefile.c (revision 9336e0699bda8a301cd2bfa37106b6ec5e32012e)
1 /*
2  * Copyright (c) 1993, 1994, 1995, 1996, 1997
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: (1) source code distributions
7  * retain the above copyright notice and this paragraph in its entirety, (2)
8  * distributions including binary code include the above copyright notice and
9  * this paragraph in its entirety in the documentation or other materials
10  * provided with the distribution, and (3) all advertising materials mentioning
11  * features or use of this software display the following acknowledgement:
12  * ``This product includes software developed by the University of California,
13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14  * the University nor the names of its contributors may be used to endorse
15  * or promote products derived from this software without specific prior
16  * written permission.
17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20  *
21  * savefile.c - supports offline use of tcpdump
22  *	Extraction/creation by Jeffrey Mogul, DECWRL
23  *	Modified by Steve McCanne, LBL.
24  *
25  * Used to save the received packet headers, after filtering, to
26  * a file, and then read them later.
27  * The first record in the file contains saved values for the machine
28  * dependent values so we can print the dump file on any architecture.
29  */
30 
31 #ifndef lint
32 static const char rcsid[] _U_ =
33     "@(#) $Header: /tcpdump/master/libpcap/savefile.c,v 1.126.2.30 2007/08/14 20:57:49 guy Exp $ (LBL)";
34 #endif
35 
36 #ifdef HAVE_CONFIG_H
37 #include "config.h"
38 #endif
39 
40 #include <errno.h>
41 #include <memory.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 
46 #include "pcap-int.h"
47 
48 #ifdef HAVE_OS_PROTO_H
49 #include "os-proto.h"
50 #endif
51 
52 /*
53  * Standard libpcap format.
54  */
55 #define TCPDUMP_MAGIC		0xa1b2c3d4
56 
57 /*
58  * Alexey Kuznetzov's modified libpcap format.
59  */
60 #define KUZNETZOV_TCPDUMP_MAGIC	0xa1b2cd34
61 
62 /*
63  * Reserved for Francisco Mesquita <francisco.mesquita@radiomovel.pt>
64  * for another modified format.
65  */
66 #define FMESQUITA_TCPDUMP_MAGIC	0xa1b234cd
67 
68 /*
69  * Navtel Communcations' format, with nanosecond timestamps,
70  * as per a request from Dumas Hwang <dumas.hwang@navtelcom.com>.
71  */
72 #define NAVTEL_TCPDUMP_MAGIC	0xa12b3c4d
73 
74 /*
75  * Normal libpcap format, except for seconds/nanoseconds timestamps,
76  * as per a request by Ulf Lamping <ulf.lamping@web.de>
77  */
78 #define NSEC_TCPDUMP_MAGIC	0xa1b23c4d
79 
80 /*
81  * We use the "receiver-makes-right" approach to byte order,
82  * because time is at a premium when we are writing the file.
83  * In other words, the pcap_file_header and pcap_pkthdr,
84  * records are written in host byte order.
85  * Note that the bytes of packet data are written out in the order in
86  * which they were received, so multi-byte fields in packets are not
87  * written in host byte order, they're written in whatever order the
88  * sending machine put them in.
89  *
90  * ntoh[ls] aren't sufficient because we might need to swap on a big-endian
91  * machine (if the file was written in little-end order).
92  */
93 #define	SWAPLONG(y) \
94 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
95 #define	SWAPSHORT(y) \
96 	( (((y)&0xff)<<8) | ((u_short)((y)&0xff00)>>8) )
97 
98 #define SFERR_TRUNC		1
99 #define SFERR_BADVERSION	2
100 #define SFERR_BADF		3
101 #define SFERR_EOF		4 /* not really an error, just a status */
102 
103 /*
104  * Setting O_BINARY on DOS/Windows is a bit tricky
105  */
106 #if defined(WIN32)
107   #define SET_BINMODE(f)  _setmode(_fileno(f), _O_BINARY)
108 #elif defined(MSDOS)
109   #if defined(__HIGHC__)
110   #define SET_BINMODE(f)  setmode(f, O_BINARY)
111   #else
112   #define SET_BINMODE(f)  setmode(fileno(f), O_BINARY)
113   #endif
114 #endif
115 
116 /*
117  * We don't write DLT_* values to the capture file header, because
118  * they're not the same on all platforms.
119  *
120  * Unfortunately, the various flavors of BSD have not always used the same
121  * numerical values for the same data types, and various patches to
122  * libpcap for non-BSD OSes have added their own DLT_* codes for link
123  * layer encapsulation types seen on those OSes, and those codes have had,
124  * in some cases, values that were also used, on other platforms, for other
125  * link layer encapsulation types.
126  *
127  * This means that capture files of a type whose numerical DLT_* code
128  * means different things on different BSDs, or with different versions
129  * of libpcap, can't always be read on systems other than those like
130  * the one running on the machine on which the capture was made.
131  *
132  * Instead, we define here a set of LINKTYPE_* codes, and map DLT_* codes
133  * to LINKTYPE_* codes when writing a savefile header, and map LINKTYPE_*
134  * codes to DLT_* codes when reading a savefile header.
135  *
136  * For those DLT_* codes that have, as far as we know, the same values on
137  * all platforms (DLT_NULL through DLT_FDDI), we define LINKTYPE_xxx as
138  * DLT_xxx; that way, captures of those types can still be read by
139  * versions of libpcap that map LINKTYPE_* values to DLT_* values, and
140  * captures of those types written by versions of libpcap that map DLT_
141  * values to LINKTYPE_ values can still be read by older versions
142  * of libpcap.
143  *
144  * The other LINKTYPE_* codes are given values starting at 100, in the
145  * hopes that no DLT_* code will be given one of those values.
146  *
147  * In order to ensure that a given LINKTYPE_* code's value will refer to
148  * the same encapsulation type on all platforms, you should not allocate
149  * a new LINKTYPE_* value without consulting "tcpdump-workers@tcpdump.org".
150  * The tcpdump developers will allocate a value for you, and will not
151  * subsequently allocate it to anybody else; that value will be added to
152  * the "pcap.h" in the tcpdump.org CVS repository, so that a future
153  * libpcap release will include it.
154  *
155  * You should, if possible, also contribute patches to libpcap and tcpdump
156  * to handle the new encapsulation type, so that they can also be checked
157  * into the tcpdump.org CVS repository and so that they will appear in
158  * future libpcap and tcpdump releases.
159  *
160  * Do *NOT* assume that any values after the largest value in this file
161  * are available; you might not have the most up-to-date version of this
162  * file, and new values after that one might have been assigned.  Also,
163  * do *NOT* use any values below 100 - those might already have been
164  * taken by one (or more!) organizations.
165  */
166 #define LINKTYPE_NULL		DLT_NULL
167 #define LINKTYPE_ETHERNET	DLT_EN10MB	/* also for 100Mb and up */
168 #define LINKTYPE_EXP_ETHERNET	DLT_EN3MB	/* 3Mb experimental Ethernet */
169 #define LINKTYPE_AX25		DLT_AX25
170 #define LINKTYPE_PRONET		DLT_PRONET
171 #define LINKTYPE_CHAOS		DLT_CHAOS
172 #define LINKTYPE_TOKEN_RING	DLT_IEEE802	/* DLT_IEEE802 is used for Token Ring */
173 #define LINKTYPE_ARCNET		DLT_ARCNET	/* BSD-style headers */
174 #define LINKTYPE_SLIP		DLT_SLIP
175 #define LINKTYPE_PPP		DLT_PPP
176 #define LINKTYPE_FDDI		DLT_FDDI
177 
178 /*
179  * LINKTYPE_PPP is for use when there might, or might not, be an RFC 1662
180  * PPP in HDLC-like framing header (with 0xff 0x03 before the PPP protocol
181  * field) at the beginning of the packet.
182  *
183  * This is for use when there is always such a header; the address field
184  * might be 0xff, for regular PPP, or it might be an address field for Cisco
185  * point-to-point with HDLC framing as per section 4.3.1 of RFC 1547 ("Cisco
186  * HDLC").  This is, for example, what you get with NetBSD's DLT_PPP_SERIAL.
187  *
188  * We give it the same value as NetBSD's DLT_PPP_SERIAL, in the hopes that
189  * nobody else will choose a DLT_ value of 50, and so that DLT_PPP_SERIAL
190  * captures will be written out with a link type that NetBSD's tcpdump
191  * can read.
192  */
193 #define LINKTYPE_PPP_HDLC	50		/* PPP in HDLC-like framing */
194 
195 #define LINKTYPE_PPP_ETHER	51		/* NetBSD PPP-over-Ethernet */
196 
197 #define LINKTYPE_SYMANTEC_FIREWALL 99		/* Symantec Enterprise Firewall */
198 
199 #define LINKTYPE_ATM_RFC1483	100		/* LLC/SNAP-encapsulated ATM */
200 #define LINKTYPE_RAW		101		/* raw IP */
201 #define LINKTYPE_SLIP_BSDOS	102		/* BSD/OS SLIP BPF header */
202 #define LINKTYPE_PPP_BSDOS	103		/* BSD/OS PPP BPF header */
203 #define LINKTYPE_C_HDLC		104		/* Cisco HDLC */
204 #define LINKTYPE_IEEE802_11	105		/* IEEE 802.11 (wireless) */
205 #define LINKTYPE_ATM_CLIP	106		/* Linux Classical IP over ATM */
206 #define LINKTYPE_FRELAY		107		/* Frame Relay */
207 #define LINKTYPE_LOOP		108		/* OpenBSD loopback */
208 #define LINKTYPE_ENC		109		/* OpenBSD IPSEC enc */
209 
210 /*
211  * These three types are reserved for future use.
212  */
213 #define LINKTYPE_LANE8023	110		/* ATM LANE + 802.3 */
214 #define LINKTYPE_HIPPI		111		/* NetBSD HIPPI */
215 #define LINKTYPE_HDLC		112		/* NetBSD HDLC framing */
216 
217 #define LINKTYPE_LINUX_SLL	113		/* Linux cooked socket capture */
218 #define LINKTYPE_LTALK		114		/* Apple LocalTalk hardware */
219 #define LINKTYPE_ECONET		115		/* Acorn Econet */
220 
221 /*
222  * Reserved for use with OpenBSD ipfilter.
223  */
224 #define LINKTYPE_IPFILTER	116
225 
226 #define LINKTYPE_PFLOG		117		/* OpenBSD DLT_PFLOG */
227 #define LINKTYPE_CISCO_IOS	118		/* For Cisco-internal use */
228 #define LINKTYPE_PRISM_HEADER	119		/* 802.11+Prism II monitor mode */
229 #define LINKTYPE_AIRONET_HEADER	120		/* FreeBSD Aironet driver stuff */
230 
231 /*
232  * Reserved for Siemens HiPath HDLC.
233  */
234 #define LINKTYPE_HHDLC		121
235 
236 #define LINKTYPE_IP_OVER_FC	122		/* RFC 2625 IP-over-Fibre Channel */
237 #define LINKTYPE_SUNATM		123		/* Solaris+SunATM */
238 
239 /*
240  * Reserved as per request from Kent Dahlgren <kent@praesum.com>
241  * for private use.
242  */
243 #define LINKTYPE_RIO		124		/* RapidIO */
244 #define LINKTYPE_PCI_EXP	125		/* PCI Express */
245 #define LINKTYPE_AURORA		126		/* Xilinx Aurora link layer */
246 
247 #define LINKTYPE_IEEE802_11_RADIO 127		/* 802.11 plus BSD radio header */
248 
249 /*
250  * Reserved for the TZSP encapsulation, as per request from
251  * Chris Waters <chris.waters@networkchemistry.com>
252  * TZSP is a generic encapsulation for any other link type,
253  * which includes a means to include meta-information
254  * with the packet, e.g. signal strength and channel
255  * for 802.11 packets.
256  */
257 #define LINKTYPE_TZSP		128		/* Tazmen Sniffer Protocol */
258 
259 #define LINKTYPE_ARCNET_LINUX	129		/* Linux-style headers */
260 
261 /*
262  * Juniper-private data link types, as per request from
263  * Hannes Gredler <hannes@juniper.net>.  The corresponding
264  * DLT_s are used for passing on chassis-internal
265  * metainformation such as QOS profiles, etc..
266  */
267 #define LINKTYPE_JUNIPER_MLPPP  130
268 #define LINKTYPE_JUNIPER_MLFR   131
269 #define LINKTYPE_JUNIPER_ES     132
270 #define LINKTYPE_JUNIPER_GGSN   133
271 #define LINKTYPE_JUNIPER_MFR    134
272 #define LINKTYPE_JUNIPER_ATM2   135
273 #define LINKTYPE_JUNIPER_SERVICES 136
274 #define LINKTYPE_JUNIPER_ATM1   137
275 
276 #define LINKTYPE_APPLE_IP_OVER_IEEE1394 138	/* Apple IP-over-IEEE 1394 cooked header */
277 
278 #define LINKTYPE_MTP2_WITH_PHDR	139
279 #define LINKTYPE_MTP2		140
280 #define LINKTYPE_MTP3		141
281 #define LINKTYPE_SCCP		142
282 
283 #define LINKTYPE_DOCSIS		143		/* DOCSIS MAC frames */
284 
285 #define LINKTYPE_LINUX_IRDA	144		/* Linux-IrDA */
286 
287 /*
288  * Reserved for IBM SP switch and IBM Next Federation switch.
289  */
290 #define LINKTYPE_IBM_SP		145
291 #define LINKTYPE_IBM_SN		146
292 
293 /*
294  * Reserved for private use.  If you have some link-layer header type
295  * that you want to use within your organization, with the capture files
296  * using that link-layer header type not ever be sent outside your
297  * organization, you can use these values.
298  *
299  * No libpcap release will use these for any purpose, nor will any
300  * tcpdump release use them, either.
301  *
302  * Do *NOT* use these in capture files that you expect anybody not using
303  * your private versions of capture-file-reading tools to read; in
304  * particular, do *NOT* use them in products, otherwise you may find that
305  * people won't be able to use tcpdump, or snort, or Ethereal, or... to
306  * read capture files from your firewall/intrusion detection/traffic
307  * monitoring/etc. appliance, or whatever product uses that LINKTYPE_ value,
308  * and you may also find that the developers of those applications will
309  * not accept patches to let them read those files.
310  *
311  * Also, do not use them if somebody might send you a capture using them
312  * for *their* private type and tools using them for *your* private type
313  * would have to read them.
314  *
315  * Instead, in those cases, ask "tcpdump-workers@tcpdump.org" for a new DLT_
316  * and LINKTYPE_ value, as per the comment in pcap-bpf.h, and use the type
317  * you're given.
318  */
319 #define LINKTYPE_USER0		147
320 #define LINKTYPE_USER1		148
321 #define LINKTYPE_USER2		149
322 #define LINKTYPE_USER3		150
323 #define LINKTYPE_USER4		151
324 #define LINKTYPE_USER5		152
325 #define LINKTYPE_USER6		153
326 #define LINKTYPE_USER7		154
327 #define LINKTYPE_USER8		155
328 #define LINKTYPE_USER9		156
329 #define LINKTYPE_USER10		157
330 #define LINKTYPE_USER11		158
331 #define LINKTYPE_USER12		159
332 #define LINKTYPE_USER13		160
333 #define LINKTYPE_USER14		161
334 #define LINKTYPE_USER15		162
335 
336 /*
337  * For future use with 802.11 captures - defined by AbsoluteValue
338  * Systems to store a number of bits of link-layer information
339  * including radio information:
340  *
341  *	http://www.shaftnet.org/~pizza/software/capturefrm.txt
342  *
343  * but could and arguably should also be used by non-AVS Linux
344  * 802.11 drivers; that may happen in the future.
345  */
346 #define LINKTYPE_IEEE802_11_RADIO_AVS 163	/* 802.11 plus AVS radio header */
347 
348 /*
349  * Juniper-private data link type, as per request from
350  * Hannes Gredler <hannes@juniper.net>.  The corresponding
351  * DLT_s are used for passing on chassis-internal
352  * metainformation such as QOS profiles, etc..
353  */
354 #define LINKTYPE_JUNIPER_MONITOR 164
355 
356 /*
357  * Reserved for BACnet MS/TP.
358  */
359 #define LINKTYPE_BACNET_MS_TP	165
360 
361 /*
362  * Another PPP variant as per request from Karsten Keil <kkeil@suse.de>.
363  *
364  * This is used in some OSes to allow a kernel socket filter to distinguish
365  * between incoming and outgoing packets, on a socket intended to
366  * supply pppd with outgoing packets so it can do dial-on-demand and
367  * hangup-on-lack-of-demand; incoming packets are filtered out so they
368  * don't cause pppd to hold the connection up (you don't want random
369  * input packets such as port scans, packets from old lost connections,
370  * etc. to force the connection to stay up).
371  *
372  * The first byte of the PPP header (0xff03) is modified to accomodate
373  * the direction - 0x00 = IN, 0x01 = OUT.
374  */
375 #define LINKTYPE_PPP_PPPD	166
376 
377 /*
378  * Juniper-private data link type, as per request from
379  * Hannes Gredler <hannes@juniper.net>.  The DLT_s are used
380  * for passing on chassis-internal metainformation such as
381  * QOS profiles, cookies, etc..
382  */
383 #define LINKTYPE_JUNIPER_PPPOE     167
384 #define LINKTYPE_JUNIPER_PPPOE_ATM 168
385 
386 #define LINKTYPE_GPRS_LLC	169		/* GPRS LLC */
387 #define LINKTYPE_GPF_T		170		/* GPF-T (ITU-T G.7041/Y.1303) */
388 #define LINKTYPE_GPF_F		171		/* GPF-T (ITU-T G.7041/Y.1303) */
389 
390 /*
391  * Requested by Oolan Zimmer <oz@gcom.com> for use in Gcom's T1/E1 line
392  * monitoring equipment.
393  */
394 #define LINKTYPE_GCOM_T1E1	172
395 #define LINKTYPE_GCOM_SERIAL	173
396 
397 /*
398  * Juniper-private data link type, as per request from
399  * Hannes Gredler <hannes@juniper.net>.  The DLT_ is used
400  * for internal communication to Physical Interface Cards (PIC)
401  */
402 #define LINKTYPE_JUNIPER_PIC_PEER    174
403 
404 /*
405  * Link types requested by Gregor Maier <gregor@endace.com> of Endace
406  * Measurement Systems.  They add an ERF header (see
407  * http://www.endace.com/support/EndaceRecordFormat.pdf) in front of
408  * the link-layer header.
409  */
410 #define LINKTYPE_ERF_ETH	175	/* Ethernet */
411 #define LINKTYPE_ERF_POS	176	/* Packet-over-SONET */
412 
413 /*
414  * Requested by Daniele Orlandi <daniele@orlandi.com> for raw LAPD
415  * for vISDN (http://www.orlandi.com/visdn/).  Its link-layer header
416  * includes additional information before the LAPD header, so it's
417  * not necessarily a generic LAPD header.
418  */
419 #define LINKTYPE_LINUX_LAPD	177
420 
421 /*
422  * Juniper-private data link type, as per request from
423  * Hannes Gredler <hannes@juniper.net>.
424  * The Link Types are used for prepending meta-information
425  * like interface index, interface name
426  * before standard Ethernet, PPP, Frelay & C-HDLC Frames
427  */
428 #define LINKTYPE_JUNIPER_ETHER  178
429 #define LINKTYPE_JUNIPER_PPP    179
430 #define LINKTYPE_JUNIPER_FRELAY 180
431 #define LINKTYPE_JUNIPER_CHDLC  181
432 
433 /*
434  * Multi Link Frame Relay (FRF.16)
435  */
436 #define LINKTYPE_MFR            182
437 
438 /*
439  * Juniper-private data link type, as per request from
440  * Hannes Gredler <hannes@juniper.net>.
441  * The DLT_ is used for internal communication with a
442  * voice Adapter Card (PIC)
443  */
444 #define LINKTYPE_JUNIPER_VP     183
445 
446 /*
447  * Arinc 429 frames.
448  * DLT_ requested by Gianluca Varenni <gianluca.varenni@cacetech.com>.
449  * Every frame contains a 32bit A429 label.
450  * More documentation on Arinc 429 can be found at
451  * http://www.condoreng.com/support/downloads/tutorials/ARINCTutorial.pdf
452  */
453 #define LINKTYPE_A429           184
454 
455 /*
456  * Arinc 653 Interpartition Communication messages.
457  * DLT_ requested by Gianluca Varenni <gianluca.varenni@cacetech.com>.
458  * Please refer to the A653-1 standard for more information.
459  */
460 #define LINKTYPE_A653_ICM       185
461 
462 /*
463  * USB packets, beginning with a USB setup header; requested by
464  * Paolo Abeni <paolo.abeni@email.it>.
465  */
466 #define LINKTYPE_USB		186
467 
468 /*
469  * Bluetooth HCI UART transport layer (part H:4); requested by
470  * Paolo Abeni.
471  */
472 #define LINKTYPE_BLUETOOTH_HCI_H4	187
473 
474 /*
475  * IEEE 802.16 MAC Common Part Sublayer; requested by Maria Cruz
476  * <cruz_petagay@bah.com>.
477  */
478 #define LINKTYPE_IEEE802_16_MAC_CPS	188
479 
480 /*
481  * USB packets, beginning with a Linux USB header; requested by
482  * Paolo Abeni <paolo.abeni@email.it>.
483  */
484 #define LINKTYPE_USB_LINUX	189
485 
486 /*
487  * Controller Area Network (CAN) v. 2.0B packets.
488  * DLT_ requested by Gianluca Varenni <gianluca.varenni@cacetech.com>.
489  * Used to dump CAN packets coming from a CAN Vector board.
490  * More documentation on the CAN v2.0B frames can be found at
491  * http://www.can-cia.org/downloads/?269
492  */
493 #define LINKTYPE_CAN20B         190
494 
495 /*
496  * IEEE 802.15.4, with address fields padded, as is done by Linux
497  * drivers; requested by Juergen Schimmer.
498  */
499 #define LINKTYPE_IEEE802_15_4_LINUX	191
500 
501 /*
502  * Per Packet Information encapsulated packets.
503  * LINKTYPE_ requested by Gianluca Varenni <gianluca.varenni@cacetech.com>.
504  */
505 #define LINKTYPE_PPI			192
506 
507 /*
508  * Header for 802.16 MAC Common Part Sublayer plus a radiotap radio header;
509  * requested by Charles Clancy.
510  */
511 #define LINKTYPE_IEEE802_16_MAC_CPS_RADIO	193
512 
513 /*
514  * Juniper-private data link type, as per request from
515  * Hannes Gredler <hannes@juniper.net>.
516  * The DLT_ is used for internal communication with a
517  * integrated service module (ISM).
518  */
519 #define LINKTYPE_JUNIPER_ISM    194
520 
521 /*
522  * IEEE 802.15.4, exactly as it appears in the spec (no padding, no
523  * nothing); requested by Mikko Saarnivala <mikko.saarnivala@sensinode.com>.
524  */
525 #define LINKTYPE_IEEE802_15_4	195
526 
527 /*
528  * Various link-layer types, with a pseudo-header, for SITA
529  * (http://www.sita.aero/); requested by Fulko Hew (fulko.hew@gmail.com).
530  */
531 #define LINKTYPE_SITA		196
532 
533 /*
534  * Various link-layer types, with a pseudo-header, for Endace DAG cards;
535  * encapsulates Endace ERF records.  Requested by Stephen Donnelly
536  * <stephen@endace.com>.
537  */
538 #define LINKTYPE_ERF		197
539 
540 /*
541  * Special header prepended to Ethernet packets when capturing from a
542  * u10 Networks board.  Requested by Phil Mulholland
543  * <phil@u10networks.com>.
544  */
545 #define LINKTYPE_RAIF1		198
546 
547 /*
548  * IPMB packet for IPMI, beginning with the I2C slave address, followed
549  * by the netFn and LUN, etc..  Requested by Chanthy Toeung
550  * <chanthy.toeung@ca.kontron.com>.
551  */
552 #define LINKTYPE_IPMB		199
553 
554 
555 static struct linktype_map {
556 	int	dlt;
557 	int	linktype;
558 } map[] = {
559 	/*
560 	 * These DLT_* codes have LINKTYPE_* codes with values identical
561 	 * to the values of the corresponding DLT_* code.
562 	 */
563 	{ DLT_NULL,		LINKTYPE_NULL },
564 	{ DLT_EN10MB,		LINKTYPE_ETHERNET },
565 	{ DLT_EN3MB,		LINKTYPE_EXP_ETHERNET },
566 	{ DLT_AX25,		LINKTYPE_AX25 },
567 	{ DLT_PRONET,		LINKTYPE_PRONET },
568 	{ DLT_CHAOS,		LINKTYPE_CHAOS },
569 	{ DLT_IEEE802,		LINKTYPE_TOKEN_RING },
570 	{ DLT_ARCNET,		LINKTYPE_ARCNET },
571 	{ DLT_SLIP,		LINKTYPE_SLIP },
572 	{ DLT_PPP,		LINKTYPE_PPP },
573 	{ DLT_FDDI,	 	LINKTYPE_FDDI },
574 
575 	/*
576 	 * These DLT_* codes have different values on different
577 	 * platforms; we map them to LINKTYPE_* codes that
578 	 * have values that should never be equal to any DLT_*
579 	 * code.
580 	 */
581 #ifdef DLT_FR
582 	/* BSD/OS Frame Relay */
583 	{ DLT_FR,		LINKTYPE_FRELAY },
584 #endif
585 
586 	{ DLT_SYMANTEC_FIREWALL, LINKTYPE_SYMANTEC_FIREWALL },
587 	{ DLT_ATM_RFC1483, 	LINKTYPE_ATM_RFC1483 },
588 	{ DLT_RAW,		LINKTYPE_RAW },
589 	{ DLT_SLIP_BSDOS,	LINKTYPE_SLIP_BSDOS },
590 	{ DLT_PPP_BSDOS,	LINKTYPE_PPP_BSDOS },
591 
592 	/* BSD/OS Cisco HDLC */
593 	{ DLT_C_HDLC,		LINKTYPE_C_HDLC },
594 
595 	/*
596 	 * These DLT_* codes are not on all platforms, but, so far,
597 	 * there don't appear to be any platforms that define
598 	 * other codes with those values; we map them to
599 	 * different LINKTYPE_* values anyway, just in case.
600 	 */
601 
602 	/* Linux ATM Classical IP */
603 	{ DLT_ATM_CLIP,		LINKTYPE_ATM_CLIP },
604 
605 	/* NetBSD sync/async serial PPP (or Cisco HDLC) */
606 	{ DLT_PPP_SERIAL,	LINKTYPE_PPP_HDLC },
607 
608 	/* NetBSD PPP over Ethernet */
609 	{ DLT_PPP_ETHER,	LINKTYPE_PPP_ETHER },
610 
611 	/* IEEE 802.11 wireless */
612 	{ DLT_IEEE802_11,	LINKTYPE_IEEE802_11 },
613 
614 	/* Frame Relay */
615 	{ DLT_FRELAY,		LINKTYPE_FRELAY },
616 
617 	/* OpenBSD loopback */
618 	{ DLT_LOOP,		LINKTYPE_LOOP },
619 
620 	/* Linux cooked socket capture */
621 	{ DLT_LINUX_SLL,	LINKTYPE_LINUX_SLL },
622 
623 	/* Apple LocalTalk hardware */
624 	{ DLT_LTALK,		LINKTYPE_LTALK },
625 
626 	/* Acorn Econet */
627 	{ DLT_ECONET,		LINKTYPE_ECONET },
628 
629 	/* OpenBSD DLT_PFLOG */
630 	{ DLT_PFLOG,		LINKTYPE_PFLOG },
631 
632 	/* For Cisco-internal use */
633 	{ DLT_CISCO_IOS,	LINKTYPE_CISCO_IOS },
634 
635 	/* Prism II monitor-mode header plus 802.11 header */
636 	{ DLT_PRISM_HEADER,	LINKTYPE_PRISM_HEADER },
637 
638 	/* FreeBSD Aironet driver stuff */
639 	{ DLT_AIRONET_HEADER,	LINKTYPE_AIRONET_HEADER },
640 
641 	/* Siemens HiPath HDLC */
642 	{ DLT_HHDLC,		LINKTYPE_HHDLC },
643 
644 	/* RFC 2625 IP-over-Fibre Channel */
645 	{ DLT_IP_OVER_FC,	LINKTYPE_IP_OVER_FC },
646 
647 	/* Solaris+SunATM */
648 	{ DLT_SUNATM,		LINKTYPE_SUNATM },
649 
650 	/* RapidIO */
651 	{ DLT_RIO,		LINKTYPE_RIO },
652 
653 	/* PCI Express */
654 	{ DLT_PCI_EXP,		LINKTYPE_PCI_EXP },
655 
656 	/* Xilinx Aurora link layer */
657 	{ DLT_AURORA,		LINKTYPE_AURORA },
658 
659 	/* 802.11 plus BSD radio header */
660 	{ DLT_IEEE802_11_RADIO,	LINKTYPE_IEEE802_11_RADIO },
661 
662 	/* Tazmen Sniffer Protocol */
663 	{ DLT_TZSP,		LINKTYPE_TZSP },
664 
665 	/* Arcnet with Linux-style link-layer headers */
666 	{ DLT_ARCNET_LINUX,	LINKTYPE_ARCNET_LINUX },
667 
668         /* Juniper-internal chassis encapsulation */
669         { DLT_JUNIPER_MLPPP,    LINKTYPE_JUNIPER_MLPPP },
670         { DLT_JUNIPER_MLFR,     LINKTYPE_JUNIPER_MLFR },
671         { DLT_JUNIPER_ES,       LINKTYPE_JUNIPER_ES },
672         { DLT_JUNIPER_GGSN,     LINKTYPE_JUNIPER_GGSN },
673         { DLT_JUNIPER_MFR,      LINKTYPE_JUNIPER_MFR },
674         { DLT_JUNIPER_ATM2,     LINKTYPE_JUNIPER_ATM2 },
675         { DLT_JUNIPER_SERVICES, LINKTYPE_JUNIPER_SERVICES },
676         { DLT_JUNIPER_ATM1,     LINKTYPE_JUNIPER_ATM1 },
677 
678 	/* Apple IP-over-IEEE 1394 cooked header */
679 	{ DLT_APPLE_IP_OVER_IEEE1394, LINKTYPE_APPLE_IP_OVER_IEEE1394 },
680 
681 	/* SS7 */
682 	{ DLT_MTP2_WITH_PHDR,	LINKTYPE_MTP2_WITH_PHDR },
683 	{ DLT_MTP2,		LINKTYPE_MTP2 },
684 	{ DLT_MTP3,		LINKTYPE_MTP3 },
685 	{ DLT_SCCP,		LINKTYPE_SCCP },
686 
687 	/* DOCSIS MAC frames */
688 	{ DLT_DOCSIS,		LINKTYPE_DOCSIS },
689 
690 	/* IrDA IrLAP packets + Linux-cooked header */
691 	{ DLT_LINUX_IRDA,	LINKTYPE_LINUX_IRDA },
692 
693 	/* IBM SP and Next Federation switches */
694 	{ DLT_IBM_SP,		LINKTYPE_IBM_SP },
695 	{ DLT_IBM_SN,		LINKTYPE_IBM_SN },
696 
697 	/* 802.11 plus AVS radio header */
698 	{ DLT_IEEE802_11_RADIO_AVS, LINKTYPE_IEEE802_11_RADIO_AVS },
699 
700 	/*
701 	 * Any platform that defines additional DLT_* codes should:
702 	 *
703 	 *	request a LINKTYPE_* code and value from tcpdump.org,
704 	 *	as per the above;
705 	 *
706 	 *	add, in their version of libpcap, an entry to map
707 	 *	those DLT_* codes to the corresponding LINKTYPE_*
708 	 *	code;
709 	 *
710 	 *	redefine, in their "net/bpf.h", any DLT_* values
711 	 *	that collide with the values used by their additional
712 	 *	DLT_* codes, to remove those collisions (but without
713 	 *	making them collide with any of the LINKTYPE_*
714 	 *	values equal to 50 or above; they should also avoid
715 	 *	defining DLT_* values that collide with those
716 	 *	LINKTYPE_* values, either).
717 	 */
718 
719 	/* Juniper-internal chassis encapsulation */
720 	{ DLT_JUNIPER_MONITOR,	LINKTYPE_JUNIPER_MONITOR },
721 
722 	/* BACnet MS/TP */
723 	{ DLT_BACNET_MS_TP,	LINKTYPE_BACNET_MS_TP },
724 
725 	/* PPP for pppd, with direction flag in the PPP header */
726 	{ DLT_PPP_PPPD,		LINKTYPE_PPP_PPPD},
727 
728 	/* Juniper-internal chassis encapsulation */
729         { DLT_JUNIPER_PPPOE,    LINKTYPE_JUNIPER_PPPOE },
730         { DLT_JUNIPER_PPPOE_ATM,LINKTYPE_JUNIPER_PPPOE_ATM },
731 
732 	/* GPRS LLC */
733 	{ DLT_GPRS_LLC,		LINKTYPE_GPRS_LLC },
734 
735 	/* Transparent Generic Framing Procedure (ITU-T G.7041/Y.1303) */
736 	{ DLT_GPF_T,		LINKTYPE_GPF_T },
737 
738 	/* Framed Generic Framing Procedure (ITU-T G.7041/Y.1303) */
739 	{ DLT_GPF_F,		LINKTYPE_GPF_F },
740 
741 	{ DLT_GCOM_T1E1,	LINKTYPE_GCOM_T1E1 },
742 	{ DLT_GCOM_SERIAL,	LINKTYPE_GCOM_SERIAL },
743 
744         /* Juniper-internal chassis encapsulation */
745         { DLT_JUNIPER_PIC_PEER, LINKTYPE_JUNIPER_PIC_PEER },
746 
747 	/* Endace types */
748 	{ DLT_ERF_ETH,		LINKTYPE_ERF_ETH },
749 	{ DLT_ERF_POS,		LINKTYPE_ERF_POS },
750 
751 	/* viSDN LAPD */
752 	{ DLT_LINUX_LAPD,	LINKTYPE_LINUX_LAPD },
753 
754         /* Juniper meta-information before Ether, PPP, Frame Relay, C-HDLC Frames */
755         { DLT_JUNIPER_ETHER, LINKTYPE_JUNIPER_ETHER },
756         { DLT_JUNIPER_PPP, LINKTYPE_JUNIPER_PPP },
757         { DLT_JUNIPER_FRELAY, LINKTYPE_JUNIPER_FRELAY },
758         { DLT_JUNIPER_CHDLC, LINKTYPE_JUNIPER_CHDLC },
759 
760         /* Multi Link Frame Relay (FRF.16) */
761         { DLT_MFR,              LINKTYPE_MFR },
762 
763         /* Juniper Voice PIC */
764         { DLT_JUNIPER_VP,       LINKTYPE_JUNIPER_VP },
765 
766 	/* Controller Area Network (CAN) v2.0B */
767 	{ DLT_A429,		LINKTYPE_A429 },
768 
769 	/* Arinc 653 Interpartition Communication messages */
770 	{ DLT_A653_ICM,         LINKTYPE_A653_ICM },
771 
772 	/* USB */
773 	{ DLT_USB,		LINKTYPE_USB },
774 
775 	/* Bluetooth HCI UART transport layer */
776 	{ DLT_BLUETOOTH_HCI_H4,	LINKTYPE_BLUETOOTH_HCI_H4 },
777 
778 	/* IEEE 802.16 MAC Common Part Sublayer */
779 	{ DLT_IEEE802_16_MAC_CPS,	LINKTYPE_IEEE802_16_MAC_CPS },
780 
781 	/* USB with Linux header */
782 	{ DLT_USB_LINUX,	LINKTYPE_USB_LINUX },
783 
784 	/* Controller Area Network (CAN) v2.0B */
785 	{ DLT_CAN20B,		LINKTYPE_CAN20B },
786 
787 	/* IEEE 802.15.4 with address fields padded */
788 	{ DLT_IEEE802_15_4_LINUX,	LINKTYPE_IEEE802_15_4_LINUX },
789 
790 	/* Per Packet Information encapsulated packets */
791 	{ DLT_PPI,			LINKTYPE_PPI },
792 
793 	/* IEEE 802.16 MAC Common Part Sublayer plus radiotap header */
794 	{ DLT_IEEE802_16_MAC_CPS_RADIO, LINKTYPE_IEEE802_16_MAC_CPS_RADIO },
795 
796         /* Juniper Voice ISM */
797         { DLT_JUNIPER_ISM,      LINKTYPE_JUNIPER_ISM },
798 
799 	/* IEEE 802.15.4 exactly as it appears in the spec */
800         { DLT_IEEE802_15_4,	LINKTYPE_IEEE802_15_4 },
801 
802 	/* Various link-layer types for SITA */
803 	{ DLT_SITA,		LINKTYPE_SITA },
804 
805 	/* Various link-layer types for Endace */
806 	{ DLT_ERF,		LINKTYPE_ERF },
807 
808 	/* Special header for u10 Networks boards */
809 	{ DLT_RAIF1,		LINKTYPE_RAIF1 },
810 
811 	/* IPMB */
812 	{ DLT_IPMB,		LINKTYPE_IPMB },
813 
814 	{ -1,			-1 }
815 };
816 
817 static int
818 dlt_to_linktype(int dlt)
819 {
820 	int i;
821 
822 	for (i = 0; map[i].dlt != -1; i++) {
823 		if (map[i].dlt == dlt)
824 			return (map[i].linktype);
825 	}
826 
827 	/*
828 	 * If we don't have a mapping for this DLT_ code, return an
829 	 * error; that means that the table above needs to have an
830 	 * entry added.
831 	 */
832 	return (-1);
833 }
834 
835 static int
836 linktype_to_dlt(int linktype)
837 {
838 	int i;
839 
840 	for (i = 0; map[i].linktype != -1; i++) {
841 		if (map[i].linktype == linktype)
842 			return (map[i].dlt);
843 	}
844 
845 	/*
846 	 * If we don't have an entry for this link type, return
847 	 * the link type value; it may be a DLT_ value from an
848 	 * older version of libpcap.
849 	 */
850 	return linktype;
851 }
852 
853 static int
854 sf_write_header(FILE *fp, int linktype, int thiszone, int snaplen)
855 {
856 	struct pcap_file_header hdr;
857 
858 	hdr.magic = TCPDUMP_MAGIC;
859 	hdr.version_major = PCAP_VERSION_MAJOR;
860 	hdr.version_minor = PCAP_VERSION_MINOR;
861 
862 	hdr.thiszone = thiszone;
863 	hdr.snaplen = snaplen;
864 	hdr.sigfigs = 0;
865 	hdr.linktype = linktype;
866 
867 	if (fwrite((char *)&hdr, sizeof(hdr), 1, fp) != 1)
868 		return (-1);
869 
870 	return (0);
871 }
872 
873 static void
874 swap_hdr(struct pcap_file_header *hp)
875 {
876 	hp->version_major = SWAPSHORT(hp->version_major);
877 	hp->version_minor = SWAPSHORT(hp->version_minor);
878 	hp->thiszone = SWAPLONG(hp->thiszone);
879 	hp->sigfigs = SWAPLONG(hp->sigfigs);
880 	hp->snaplen = SWAPLONG(hp->snaplen);
881 	hp->linktype = SWAPLONG(hp->linktype);
882 }
883 
884 static int
885 sf_getnonblock(pcap_t *p, char *errbuf)
886 {
887 	/*
888 	 * This is a savefile, not a live capture file, so never say
889 	 * it's in non-blocking mode.
890 	 */
891 	return (0);
892 }
893 
894 static int
895 sf_setnonblock(pcap_t *p, int nonblock, char *errbuf)
896 {
897 	/*
898 	 * This is a savefile, not a live capture file, so ignore
899 	 * requests to put it in non-blocking mode.
900 	 */
901 	return (0);
902 }
903 
904 static int
905 sf_stats(pcap_t *p, struct pcap_stat *ps)
906 {
907 	snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
908 	    "Statistics aren't available from savefiles");
909 	return (-1);
910 }
911 
912 static int
913 sf_inject(pcap_t *p, const void *buf _U_, size_t size _U_)
914 {
915 	strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
916 	    PCAP_ERRBUF_SIZE);
917 	return (-1);
918 }
919 
920 /*
921  * Set direction flag: Which packets do we accept on a forwarding
922  * single device? IN, OUT or both?
923  */
924 static int
925 sf_setdirection(pcap_t *p, pcap_direction_t d)
926 {
927 	snprintf(p->errbuf, sizeof(p->errbuf),
928 	    "Setting direction is not supported on savefiles");
929 	return (-1);
930 }
931 
932 static void
933 sf_close(pcap_t *p)
934 {
935 	if (p->sf.rfile != stdin)
936 		(void)fclose(p->sf.rfile);
937 	if (p->sf.base != NULL)
938 		free(p->sf.base);
939 }
940 
941 pcap_t *
942 pcap_open_offline(const char *fname, char *errbuf)
943 {
944 	FILE *fp;
945 	pcap_t *p;
946 
947 	if (fname[0] == '-' && fname[1] == '\0')
948 	{
949 		fp = stdin;
950 #if defined(WIN32) || defined(MSDOS)
951 		/*
952 		 * We're reading from the standard input, so put it in binary
953 		 * mode, as savefiles are binary files.
954 		 */
955 		SET_BINMODE(fp);
956 #endif
957 	}
958 	else {
959 #if !defined(WIN32) && !defined(MSDOS)
960 		fp = fopen(fname, "r");
961 #else
962 		fp = fopen(fname, "rb");
963 #endif
964 		if (fp == NULL) {
965 			snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname,
966 			    pcap_strerror(errno));
967 			return (NULL);
968 		}
969 	}
970 	p = pcap_fopen_offline(fp, errbuf);
971 	if (p == NULL) {
972 		if (fp != stdin)
973 			fclose(fp);
974 	}
975 	return (p);
976 }
977 
978 pcap_t *
979 pcap_fopen_offline(FILE *fp, char *errbuf)
980 {
981 	register pcap_t *p;
982 	struct pcap_file_header hdr;
983 	size_t amt_read;
984 	bpf_u_int32 magic;
985 	int linklen;
986 
987 	p = (pcap_t *)malloc(sizeof(*p));
988 	if (p == NULL) {
989 		strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
990 		return (NULL);
991 	}
992 
993 	memset((char *)p, 0, sizeof(*p));
994 
995 	amt_read = fread((char *)&hdr, 1, sizeof(hdr), fp);
996 	if (amt_read != sizeof(hdr)) {
997 		if (ferror(fp)) {
998 			snprintf(errbuf, PCAP_ERRBUF_SIZE,
999 			    "error reading dump file: %s",
1000 			    pcap_strerror(errno));
1001 		} else {
1002 			snprintf(errbuf, PCAP_ERRBUF_SIZE,
1003 			    "truncated dump file; tried to read %lu file header bytes, only got %lu",
1004 			    (unsigned long)sizeof(hdr),
1005 			    (unsigned long)amt_read);
1006 		}
1007 		goto bad;
1008 	}
1009 	magic = hdr.magic;
1010 	if (magic != TCPDUMP_MAGIC && magic != KUZNETZOV_TCPDUMP_MAGIC) {
1011 		magic = SWAPLONG(magic);
1012 		if (magic != TCPDUMP_MAGIC && magic != KUZNETZOV_TCPDUMP_MAGIC) {
1013 			snprintf(errbuf, PCAP_ERRBUF_SIZE,
1014 			    "bad dump file format");
1015 			goto bad;
1016 		}
1017 		p->sf.swapped = 1;
1018 		swap_hdr(&hdr);
1019 	}
1020 	if (magic == KUZNETZOV_TCPDUMP_MAGIC) {
1021 		/*
1022 		 * XXX - the patch that's in some versions of libpcap
1023 		 * changes the packet header but not the magic number,
1024 		 * and some other versions with this magic number have
1025 		 * some extra debugging information in the packet header;
1026 		 * we'd have to use some hacks^H^H^H^H^Hheuristics to
1027 		 * detect those variants.
1028 		 *
1029 		 * Ethereal does that, but it does so by trying to read
1030 		 * the first two packets of the file with each of the
1031 		 * record header formats.  That currently means it seeks
1032 		 * backwards and retries the reads, which doesn't work
1033 		 * on pipes.  We want to be able to read from a pipe, so
1034 		 * that strategy won't work; we'd have to buffer some
1035 		 * data ourselves and read from that buffer in order to
1036 		 * make that work.
1037 		 */
1038 		p->sf.hdrsize = sizeof(struct pcap_sf_patched_pkthdr);
1039 	} else
1040 		p->sf.hdrsize = sizeof(struct pcap_sf_pkthdr);
1041 	if (hdr.version_major < PCAP_VERSION_MAJOR) {
1042 		snprintf(errbuf, PCAP_ERRBUF_SIZE, "archaic file format");
1043 		goto bad;
1044 	}
1045 	p->tzoff = hdr.thiszone;
1046 	p->snapshot = hdr.snaplen;
1047 	p->linktype = linktype_to_dlt(hdr.linktype);
1048 	if (magic == KUZNETZOV_TCPDUMP_MAGIC && p->linktype == DLT_EN10MB) {
1049 		/*
1050 		 * This capture might have been done in raw mode or cooked
1051 		 * mode.
1052 		 *
1053 		 * If it was done in cooked mode, p->snapshot was passed
1054 		 * to recvfrom() as the buffer size, meaning that the
1055 		 * most packet data that would be copied would be
1056 		 * p->snapshot.  However, a faked Ethernet header would
1057 		 * then have been added to it, so the most data that would
1058 		 * be in a packet in the file would be p->snapshot + 14.
1059 		 *
1060 		 * We can't easily tell whether the capture was done in
1061 		 * raw mode or cooked mode, so we'll assume it was
1062 		 * cooked mode, and add 14 to the snapshot length.  That
1063 		 * means that, for a raw capture, the snapshot length will
1064 		 * be misleading if you use it to figure out why a capture
1065 		 * doesn't have all the packet data, but there's not much
1066 		 * we can do to avoid that.
1067 		 */
1068 		p->snapshot += 14;
1069 	}
1070 	p->sf.rfile = fp;
1071 #ifndef WIN32
1072 	p->bufsize = hdr.snaplen;
1073 #else
1074 	/* Allocate the space for pcap_pkthdr as well. It will be used by pcap_read_ex */
1075 	p->bufsize = hdr.snaplen+sizeof(struct pcap_pkthdr);
1076 #endif
1077 
1078 	/* Align link header as required for proper data alignment */
1079 	/* XXX should handle all types */
1080 	switch (p->linktype) {
1081 
1082 	case DLT_EN10MB:
1083 		linklen = 14;
1084 		break;
1085 
1086 	case DLT_FDDI:
1087 		linklen = 13 + 8;	/* fddi_header + llc */
1088 		break;
1089 
1090 	case DLT_NULL:
1091 	default:
1092 		linklen = 0;
1093 		break;
1094 	}
1095 
1096 	if (p->bufsize < 0)
1097 		p->bufsize = BPF_MAXBUFSIZE;
1098 	p->sf.base = (u_char *)malloc(p->bufsize + BPF_ALIGNMENT);
1099 	if (p->sf.base == NULL) {
1100 		strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
1101 		goto bad;
1102 	}
1103 	p->buffer = p->sf.base + BPF_ALIGNMENT - (linklen % BPF_ALIGNMENT);
1104 	p->sf.version_major = hdr.version_major;
1105 	p->sf.version_minor = hdr.version_minor;
1106 #ifdef PCAP_FDDIPAD
1107 	/* Padding only needed for live capture fcode */
1108 	p->fddipad = 0;
1109 #endif
1110 
1111 	/*
1112 	 * We interchanged the caplen and len fields at version 2.3,
1113 	 * in order to match the bpf header layout.  But unfortunately
1114 	 * some files were written with version 2.3 in their headers
1115 	 * but without the interchanged fields.
1116 	 *
1117 	 * In addition, DG/UX tcpdump writes out files with a version
1118 	 * number of 543.0, and with the caplen and len fields in the
1119 	 * pre-2.3 order.
1120 	 */
1121 	switch (hdr.version_major) {
1122 
1123 	case 2:
1124 		if (hdr.version_minor < 3)
1125 			p->sf.lengths_swapped = SWAPPED;
1126 		else if (hdr.version_minor == 3)
1127 			p->sf.lengths_swapped = MAYBE_SWAPPED;
1128 		else
1129 			p->sf.lengths_swapped = NOT_SWAPPED;
1130 		break;
1131 
1132 	case 543:
1133 		p->sf.lengths_swapped = SWAPPED;
1134 		break;
1135 
1136 	default:
1137 		p->sf.lengths_swapped = NOT_SWAPPED;
1138 		break;
1139 	}
1140 
1141 #if !defined(WIN32) && !defined(MSDOS)
1142 	/*
1143 	 * You can do "select()" and "poll()" on plain files on most
1144 	 * platforms, and should be able to do so on pipes.
1145 	 *
1146 	 * You can't do "select()" on anything other than sockets in
1147 	 * Windows, so, on Win32 systems, we don't have "selectable_fd".
1148 	 */
1149 	p->selectable_fd = fileno(fp);
1150 #endif
1151 
1152 	p->read_op = pcap_offline_read;
1153 	p->inject_op = sf_inject;
1154 	p->setfilter_op = install_bpf_program;
1155 	p->setdirection_op = sf_setdirection;
1156 	p->set_datalink_op = NULL;	/* we don't support munging link-layer headers */
1157 	p->getnonblock_op = sf_getnonblock;
1158 	p->setnonblock_op = sf_setnonblock;
1159 	p->stats_op = sf_stats;
1160 	p->close_op = sf_close;
1161 
1162 	return (p);
1163  bad:
1164 	free(p);
1165 	return (NULL);
1166 }
1167 
1168 /*
1169  * Read sf_readfile and return the next packet.  Return the header in hdr
1170  * and the contents in buf.  Return 0 on success, SFERR_EOF if there were
1171  * no more packets, and SFERR_TRUNC if a partial packet was encountered.
1172  */
1173 static int
1174 sf_next_packet(pcap_t *p, struct pcap_pkthdr *hdr, u_char *buf, u_int buflen)
1175 {
1176 	struct pcap_sf_patched_pkthdr sf_hdr;
1177 	FILE *fp = p->sf.rfile;
1178 	size_t amt_read;
1179 	bpf_u_int32 t;
1180 
1181 	/*
1182 	 * Read the packet header; the structure we use as a buffer
1183 	 * is the longer structure for files generated by the patched
1184 	 * libpcap, but if the file has the magic number for an
1185 	 * unpatched libpcap we only read as many bytes as the regular
1186 	 * header has.
1187 	 */
1188 	amt_read = fread(&sf_hdr, 1, p->sf.hdrsize, fp);
1189 	if (amt_read != p->sf.hdrsize) {
1190 		if (ferror(fp)) {
1191 			snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
1192 			    "error reading dump file: %s",
1193 			    pcap_strerror(errno));
1194 			return (-1);
1195 		} else {
1196 			if (amt_read != 0) {
1197 				snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
1198 				    "truncated dump file; tried to read %d header bytes, only got %lu",
1199 				    p->sf.hdrsize, (unsigned long)amt_read);
1200 				return (-1);
1201 			}
1202 			/* EOF */
1203 			return (1);
1204 		}
1205 	}
1206 
1207 	if (p->sf.swapped) {
1208 		/* these were written in opposite byte order */
1209 		hdr->caplen = SWAPLONG(sf_hdr.caplen);
1210 		hdr->len = SWAPLONG(sf_hdr.len);
1211 		hdr->ts.tv_sec = SWAPLONG(sf_hdr.ts.tv_sec);
1212 		hdr->ts.tv_usec = SWAPLONG(sf_hdr.ts.tv_usec);
1213 	} else {
1214 		hdr->caplen = sf_hdr.caplen;
1215 		hdr->len = sf_hdr.len;
1216 		hdr->ts.tv_sec = sf_hdr.ts.tv_sec;
1217 		hdr->ts.tv_usec = sf_hdr.ts.tv_usec;
1218 	}
1219 	/* Swap the caplen and len fields, if necessary. */
1220 	switch (p->sf.lengths_swapped) {
1221 
1222 	case NOT_SWAPPED:
1223 		break;
1224 
1225 	case MAYBE_SWAPPED:
1226 		if (hdr->caplen <= hdr->len) {
1227 			/*
1228 			 * The captured length is <= the actual length,
1229 			 * so presumably they weren't swapped.
1230 			 */
1231 			break;
1232 		}
1233 		/* FALLTHROUGH */
1234 
1235 	case SWAPPED:
1236 		t = hdr->caplen;
1237 		hdr->caplen = hdr->len;
1238 		hdr->len = t;
1239 		break;
1240 	}
1241 
1242 	if (hdr->caplen > buflen) {
1243 		/*
1244 		 * This can happen due to Solaris 2.3 systems tripping
1245 		 * over the BUFMOD problem and not setting the snapshot
1246 		 * correctly in the savefile header.  If the caplen isn't
1247 		 * grossly wrong, try to salvage.
1248 		 */
1249 		static u_char *tp = NULL;
1250 		static size_t tsize = 0;
1251 
1252 		if (hdr->caplen > 65535) {
1253 			snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
1254 			    "bogus savefile header");
1255 			return (-1);
1256 		}
1257 
1258 		if (tsize < hdr->caplen) {
1259 			tsize = ((hdr->caplen + 1023) / 1024) * 1024;
1260 			if (tp != NULL)
1261 				free((u_char *)tp);
1262 			tp = (u_char *)malloc(tsize);
1263 			if (tp == NULL) {
1264 				tsize = 0;
1265 				snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
1266 				    "BUFMOD hack malloc");
1267 				return (-1);
1268 			}
1269 		}
1270 		amt_read = fread((char *)tp, 1, hdr->caplen, fp);
1271 		if (amt_read != hdr->caplen) {
1272 			if (ferror(fp)) {
1273 				snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
1274 				    "error reading dump file: %s",
1275 				    pcap_strerror(errno));
1276 			} else {
1277 				snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
1278 				    "truncated dump file; tried to read %u captured bytes, only got %lu",
1279 				    hdr->caplen, (unsigned long)amt_read);
1280 			}
1281 			return (-1);
1282 		}
1283 		/*
1284 		 * We can only keep up to buflen bytes.  Since caplen > buflen
1285 		 * is exactly how we got here, we know we can only keep the
1286 		 * first buflen bytes and must drop the remainder.  Adjust
1287 		 * caplen accordingly, so we don't get confused later as
1288 		 * to how many bytes we have to play with.
1289 		 */
1290 		hdr->caplen = buflen;
1291 		memcpy((char *)buf, (char *)tp, buflen);
1292 
1293 	} else {
1294 		/* read the packet itself */
1295 		amt_read = fread((char *)buf, 1, hdr->caplen, fp);
1296 		if (amt_read != hdr->caplen) {
1297 			if (ferror(fp)) {
1298 				snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
1299 				    "error reading dump file: %s",
1300 				    pcap_strerror(errno));
1301 			} else {
1302 				snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
1303 				    "truncated dump file; tried to read %u captured bytes, only got %lu",
1304 				    hdr->caplen, (unsigned long)amt_read);
1305 			}
1306 			return (-1);
1307 		}
1308 	}
1309 	return (0);
1310 }
1311 
1312 /*
1313  * Print out packets stored in the file initialized by sf_read_init().
1314  * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
1315  */
1316 int
1317 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
1318 {
1319 	struct bpf_insn *fcode;
1320 	int status = 0;
1321 	int n = 0;
1322 
1323 	while (status == 0) {
1324 		struct pcap_pkthdr h;
1325 
1326 		/*
1327 		 * Has "pcap_breakloop()" been called?
1328 		 * If so, return immediately - if we haven't read any
1329 		 * packets, clear the flag and return -2 to indicate
1330 		 * that we were told to break out of the loop, otherwise
1331 		 * leave the flag set, so that the *next* call will break
1332 		 * out of the loop without having read any packets, and
1333 		 * return the number of packets we've processed so far.
1334 		 */
1335 		if (p->break_loop) {
1336 			if (n == 0) {
1337 				p->break_loop = 0;
1338 				return (-2);
1339 			} else
1340 				return (n);
1341 		}
1342 
1343 		status = sf_next_packet(p, &h, p->buffer, p->bufsize);
1344 		if (status) {
1345 			if (status == 1)
1346 				return (0);
1347 			return (status);
1348 		}
1349 
1350 		if ((fcode = p->fcode.bf_insns) == NULL ||
1351 		    bpf_filter(fcode, p->buffer, h.len, h.caplen)) {
1352 			(*callback)(user, &h, p->buffer);
1353 			if (++n >= cnt && cnt > 0)
1354 				break;
1355 		}
1356 	}
1357 	/*XXX this breaks semantics tcpslice expects */
1358 	return (n);
1359 }
1360 
1361 /*
1362  * Output a packet to the initialized dump file.
1363  */
1364 void
1365 pcap_dump(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
1366 {
1367 	register FILE *f;
1368 	struct pcap_sf_pkthdr sf_hdr;
1369 
1370 	f = (FILE *)user;
1371 	sf_hdr.ts.tv_sec  = h->ts.tv_sec;
1372 	sf_hdr.ts.tv_usec = h->ts.tv_usec;
1373 	sf_hdr.caplen     = h->caplen;
1374 	sf_hdr.len        = h->len;
1375 	/* XXX we should check the return status */
1376 	(void)fwrite(&sf_hdr, sizeof(sf_hdr), 1, f);
1377 	(void)fwrite(sp, h->caplen, 1, f);
1378 }
1379 
1380 static pcap_dumper_t *
1381 pcap_setup_dump(pcap_t *p, int linktype, FILE *f, const char *fname)
1382 {
1383 
1384 #if defined(WIN32) || defined(MSDOS)
1385 	/*
1386 	 * If we're writing to the standard output, put it in binary
1387 	 * mode, as savefiles are binary files.
1388 	 *
1389 	 * Otherwise, we turn off buffering.
1390 	 * XXX - why?  And why not on the standard output?
1391 	 */
1392 	if (f == stdout)
1393 		SET_BINMODE(f);
1394 	else
1395 		setbuf(f, NULL);
1396 #endif
1397 	if (sf_write_header(f, linktype, p->tzoff, p->snapshot) == -1) {
1398 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "Can't write to %s: %s",
1399 		    fname, pcap_strerror(errno));
1400 		if (f != stdout)
1401 			(void)fclose(f);
1402 		return (NULL);
1403 	}
1404 	return ((pcap_dumper_t *)f);
1405 }
1406 
1407 /*
1408  * Initialize so that sf_write() will output to the file named 'fname'.
1409  */
1410 pcap_dumper_t *
1411 pcap_dump_open(pcap_t *p, const char *fname)
1412 {
1413 	FILE *f;
1414 	int linktype;
1415 
1416 	linktype = dlt_to_linktype(p->linktype);
1417 	if (linktype == -1) {
1418 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
1419 		    "%s: link-layer type %d isn't supported in savefiles",
1420 		    fname, linktype);
1421 		return (NULL);
1422 	}
1423 
1424 	if (fname[0] == '-' && fname[1] == '\0') {
1425 		f = stdout;
1426 		fname = "standard output";
1427 	} else {
1428 #if !defined(WIN32) && !defined(MSDOS)
1429 		f = fopen(fname, "w");
1430 #else
1431 		f = fopen(fname, "wb");
1432 #endif
1433 		if (f == NULL) {
1434 			snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
1435 			    fname, pcap_strerror(errno));
1436 			return (NULL);
1437 		}
1438 	}
1439 	return (pcap_setup_dump(p, linktype, f, fname));
1440 }
1441 
1442 /*
1443  * Initialize so that sf_write() will output to the given stream.
1444  */
1445 pcap_dumper_t *
1446 pcap_dump_fopen(pcap_t *p, FILE *f)
1447 {
1448 	int linktype;
1449 
1450 	linktype = dlt_to_linktype(p->linktype);
1451 	if (linktype == -1) {
1452 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
1453 		    "stream: link-layer type %d isn't supported in savefiles",
1454 		    linktype);
1455 		return (NULL);
1456 	}
1457 
1458 	return (pcap_setup_dump(p, linktype, f, "stream"));
1459 }
1460 
1461 FILE *
1462 pcap_dump_file(pcap_dumper_t *p)
1463 {
1464 	return ((FILE *)p);
1465 }
1466 
1467 long
1468 pcap_dump_ftell(pcap_dumper_t *p)
1469 {
1470 	return (ftell((FILE *)p));
1471 }
1472 
1473 int
1474 pcap_dump_flush(pcap_dumper_t *p)
1475 {
1476 
1477 	if (fflush((FILE *)p) == EOF)
1478 		return (-1);
1479 	else
1480 		return (0);
1481 }
1482 
1483 void
1484 pcap_dump_close(pcap_dumper_t *p)
1485 {
1486 
1487 #ifdef notyet
1488 	if (ferror((FILE *)p))
1489 		return-an-error;
1490 	/* XXX should check return from fclose() too */
1491 #endif
1492 	(void)fclose((FILE *)p);
1493 }
1494