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Add a "pcap_dump_file()" API to get the "FILE *" corresponding to a
[libpcap] / savefile.c
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 1.95 2003-11-16 10:07:36 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 #define TCPDUMP_MAGIC 0xa1b2c3d4
53 #define PATCHED_TCPDUMP_MAGIC 0xa1b2cd34
54
55 /*
56 * We use the "receiver-makes-right" approach to byte order,
57 * because time is at a premium when we are writing the file.
58 * In other words, the pcap_file_header and pcap_pkthdr,
59 * records are written in host byte order.
60 * Note that the bytes of packet data are written out in the order in
61 * which they were received, so multi-byte fields in packets are not
62 * written in host byte order, they're written in whatever order the
63 * sending machine put them in.
64 *
65 * ntoh[ls] aren't sufficient because we might need to swap on a big-endian
66 * machine (if the file was written in little-end order).
67 */
68 #define SWAPLONG(y) \
69 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
70 #define SWAPSHORT(y) \
71 ( (((y)&0xff)<<8) | ((u_short)((y)&0xff00)>>8) )
72
73 #define SFERR_TRUNC 1
74 #define SFERR_BADVERSION 2
75 #define SFERR_BADF 3
76 #define SFERR_EOF 4 /* not really an error, just a status */
77
78 /*
79 * We don't write DLT_* values to the capture file header, because
80 * they're not the same on all platforms.
81 *
82 * Unfortunately, the various flavors of BSD have not always used the same
83 * numerical values for the same data types, and various patches to
84 * libpcap for non-BSD OSes have added their own DLT_* codes for link
85 * layer encapsulation types seen on those OSes, and those codes have had,
86 * in some cases, values that were also used, on other platforms, for other
87 * link layer encapsulation types.
88 *
89 * This means that capture files of a type whose numerical DLT_* code
90 * means different things on different BSDs, or with different versions
91 * of libpcap, can't always be read on systems other than those like
92 * the one running on the machine on which the capture was made.
93 *
94 * Instead, we define here a set of LINKTYPE_* codes, and map DLT_* codes
95 * to LINKTYPE_* codes when writing a savefile header, and map LINKTYPE_*
96 * codes to DLT_* codes when reading a savefile header.
97 *
98 * For those DLT_* codes that have, as far as we know, the same values on
99 * all platforms (DLT_NULL through DLT_FDDI), we define LINKTYPE_xxx as
100 * DLT_xxx; that way, captures of those types can still be read by
101 * versions of libpcap that map LINKTYPE_* values to DLT_* values, and
102 * captures of those types written by versions of libpcap that map DLT_
103 * values to LINKTYPE_ values can still be read by older versions
104 * of libpcap.
105 *
106 * The other LINKTYPE_* codes are given values starting at 100, in the
107 * hopes that no DLT_* code will be given one of those values.
108 *
109 * In order to ensure that a given LINKTYPE_* code's value will refer to
110 * the same encapsulation type on all platforms, you should not allocate
111 * a new LINKTYPE_* value without consulting "tcpdump-workers@tcpdump.org".
112 * The tcpdump developers will allocate a value for you, and will not
113 * subsequently allocate it to anybody else; that value will be added to
114 * the "pcap.h" in the tcpdump.org CVS repository, so that a future
115 * libpcap release will include it.
116 *
117 * You should, if possible, also contribute patches to libpcap and tcpdump
118 * to handle the new encapsulation type, so that they can also be checked
119 * into the tcpdump.org CVS repository and so that they will appear in
120 * future libpcap and tcpdump releases.
121 */
122 #define LINKTYPE_NULL DLT_NULL
123 #define LINKTYPE_ETHERNET DLT_EN10MB /* also for 100Mb and up */
124 #define LINKTYPE_EXP_ETHERNET DLT_EN3MB /* 3Mb experimental Ethernet */
125 #define LINKTYPE_AX25 DLT_AX25
126 #define LINKTYPE_PRONET DLT_PRONET
127 #define LINKTYPE_CHAOS DLT_CHAOS
128 #define LINKTYPE_TOKEN_RING DLT_IEEE802 /* DLT_IEEE802 is used for Token Ring */
129 #define LINKTYPE_ARCNET DLT_ARCNET /* BSD-style headers */
130 #define LINKTYPE_SLIP DLT_SLIP
131 #define LINKTYPE_PPP DLT_PPP
132 #define LINKTYPE_FDDI DLT_FDDI
133
134 /*
135 * LINKTYPE_PPP is for use when there might, or might not, be an RFC 1662
136 * PPP in HDLC-like framing header (with 0xff 0x03 before the PPP protocol
137 * field) at the beginning of the packet.
138 *
139 * This is for use when there is always such a header; the address field
140 * might be 0xff, for regular PPP, or it might be an address field for Cisco
141 * point-to-point with HDLC framing as per section 4.3.1 of RFC 1547 ("Cisco
142 * HDLC"). This is, for example, what you get with NetBSD's DLT_PPP_SERIAL.
143 *
144 * We give it the same value as NetBSD's DLT_PPP_SERIAL, in the hopes that
145 * nobody else will choose a DLT_ value of 50, and so that DLT_PPP_SERIAL
146 * captures will be written out with a link type that NetBSD's tcpdump
147 * can read.
148 */
149 #define LINKTYPE_PPP_HDLC 50 /* PPP in HDLC-like framing */
150
151 #define LINKTYPE_PPP_ETHER 51 /* NetBSD PPP-over-Ethernet */
152
153 #define LINKTYPE_ATM_RFC1483 100 /* LLC/SNAP-encapsulated ATM */
154 #define LINKTYPE_RAW 101 /* raw IP */
155 #define LINKTYPE_SLIP_BSDOS 102 /* BSD/OS SLIP BPF header */
156 #define LINKTYPE_PPP_BSDOS 103 /* BSD/OS PPP BPF header */
157 #define LINKTYPE_C_HDLC 104 /* Cisco HDLC */
158 #define LINKTYPE_IEEE802_11 105 /* IEEE 802.11 (wireless) */
159 #define LINKTYPE_ATM_CLIP 106 /* Linux Classical IP over ATM */
160 #define LINKTYPE_FRELAY 107 /* Frame Relay */
161 #define LINKTYPE_LOOP 108 /* OpenBSD loopback */
162 #define LINKTYPE_ENC 109 /* OpenBSD IPSEC enc */
163
164 #define LINKTYPE_LINUX_SLL 113 /* Linux cooked socket capture */
165 #define LINKTYPE_LTALK 114 /* Apple LocalTalk hardware */
166 #define LINKTYPE_ECONET 115 /* Acorn Econet */
167
168 #define LINKTYPE_PFLOG 117 /* OpenBSD DLT_PFLOG */
169 #define LINKTYPE_CISCO_IOS 118 /* For Cisco-internal use */
170 #define LINKTYPE_PRISM_HEADER 119 /* 802.11+Prism II monitor mode */
171 #define LINKTYPE_AIRONET_HEADER 120 /* FreeBSD Aironet driver stuff */
172 #define LINKTYPE_IP_OVER_FC 122 /* RFC 2625 IP-over-Fibre Channel */
173 #define LINKTYPE_SUNATM 123 /* Solaris+SunATM */
174
175 #define LINKTYPE_IEEE802_11_RADIO 127 /* 802.11 plus WLAN header */
176
177 #define LINKTYPE_TZSP 128 /* Tazmen Sniffer Protocol */
178
179 #define LINKTYPE_ARCNET_LINUX 129 /* Linux-style headers */
180
181 #define LINKTYPE_JUNIPER_MLPPP 130 /* Juniper-internal chassis encapsulation */
182 #define LINKTYPE_JUNIPER_MLFR 131
183 #define LINKTYPE_JUNIPER_ES 132
184 #define LINKTYPE_JUNIPER_GGSN 133
185 #define LINKTYPE_JUNIPER_MFR 134
186 #define LINKTYPE_JUNIPER_ATM2 135
187 #define LINKTYPE_JUNIPER_SERVICES 136
188 #define LINKTYPE_JUNIPER_ATM1 137
189
190 #define LINKTYPE_APPLE_IP_OVER_IEEE1394 138 /* Apple IP-over-IEEE 1394 cooked header */
191
192 #define LINKTYPE_RAWSS7 139 /* see rawss7.h for */
193 #define LINKTYPE_RAWSS7_MTP2 140 /* information on these */
194 #define LINKTYPE_RAWSS7_MTP3 141 /* definitions */
195 #define LINKTYPE_RAWSS7_SCCP 142
196
197 #define LINKTYPE_DOCSIS 143 /* DOCSIS MAC frames */
198
199 /*
200 * These types are reserved for future use.
201 */
202 #define LINKTYPE_LANE8023 110 /* ATM LANE + 802.3 */
203 #define LINKTYPE_HIPPI 111 /* NetBSD HIPPI */
204 #define LINKTYPE_HDLC 112 /* NetBSD HDLC framing */
205 #define LINKTYPE_IPFILTER 116 /* IP Filter capture files */
206 #define LINKTYPE_HHDLC 121 /* Siemens HiPath HDLC */
207 #define LINKTYPE_RIO 124 /* RapidIO */
208 #define LINKTYPE_PCI_EXP 125 /* PCI Express */
209 #define LINKTYPE_AURORA 126 /* Xilinx Aurora link layer */
210
211 static struct linktype_map {
212 int dlt;
213 int linktype;
214 } map[] = {
215 /*
216 * These DLT_* codes have LINKTYPE_* codes with values identical
217 * to the values of the corresponding DLT_* code.
218 */
219 { DLT_NULL, LINKTYPE_NULL },
220 { DLT_EN10MB, LINKTYPE_ETHERNET },
221 { DLT_EN3MB, LINKTYPE_EXP_ETHERNET },
222 { DLT_AX25, LINKTYPE_AX25 },
223 { DLT_PRONET, LINKTYPE_PRONET },
224 { DLT_CHAOS, LINKTYPE_CHAOS },
225 { DLT_IEEE802, LINKTYPE_TOKEN_RING },
226 { DLT_ARCNET, LINKTYPE_ARCNET },
227 { DLT_SLIP, LINKTYPE_SLIP },
228 { DLT_PPP, LINKTYPE_PPP },
229 { DLT_FDDI, LINKTYPE_FDDI },
230
231 /*
232 * These DLT_* codes have different values on different
233 * platforms; we map them to LINKTYPE_* codes that
234 * have values that should never be equal to any DLT_*
235 * code.
236 */
237 #ifdef DLT_FR
238 /* BSD/OS Frame Relay */
239 { DLT_FR, LINKTYPE_FRELAY },
240 #endif
241 { DLT_ATM_RFC1483, LINKTYPE_ATM_RFC1483 },
242 { DLT_RAW, LINKTYPE_RAW },
243 { DLT_SLIP_BSDOS, LINKTYPE_SLIP_BSDOS },
244 { DLT_PPP_BSDOS, LINKTYPE_PPP_BSDOS },
245
246 /* BSD/OS Cisco HDLC */
247 { DLT_C_HDLC, LINKTYPE_C_HDLC },
248
249 /*
250 * These DLT_* codes are not on all platforms, but, so far,
251 * there don't appear to be any platforms that define
252 * other codes with those values; we map them to
253 * different LINKTYPE_* values anyway, just in case.
254 */
255
256 /* Linux ATM Classical IP */
257 { DLT_ATM_CLIP, LINKTYPE_ATM_CLIP },
258
259 /* NetBSD sync/async serial PPP (or Cisco HDLC) */
260 { DLT_PPP_SERIAL, LINKTYPE_PPP_HDLC },
261
262 /* NetBSD PPP over Ethernet */
263 { DLT_PPP_ETHER, LINKTYPE_PPP_ETHER },
264
265 /* IEEE 802.11 wireless */
266 { DLT_IEEE802_11, LINKTYPE_IEEE802_11 },
267
268 /* Frame Relay */
269 { DLT_FRELAY, LINKTYPE_FRELAY },
270
271 /* OpenBSD loopback */
272 { DLT_LOOP, LINKTYPE_LOOP },
273
274 /* Linux cooked socket capture */
275 { DLT_LINUX_SLL, LINKTYPE_LINUX_SLL },
276
277 /* Apple LocalTalk hardware */
278 { DLT_LTALK, LINKTYPE_LTALK },
279
280 /* Acorn Econet */
281 { DLT_ECONET, LINKTYPE_ECONET },
282
283 /* OpenBSD DLT_PFLOG */
284 { DLT_PFLOG, LINKTYPE_PFLOG },
285
286 /* For Cisco-internal use */
287 { DLT_CISCO_IOS, LINKTYPE_CISCO_IOS },
288
289 /* Prism II monitor-mode header plus 802.11 header */
290 { DLT_PRISM_HEADER, LINKTYPE_PRISM_HEADER },
291
292 /* FreeBSD Aironet driver stuff */
293 { DLT_AIRONET_HEADER, LINKTYPE_AIRONET_HEADER },
294
295 /* Siemens HiPath HDLC */
296 { DLT_HHDLC, LINKTYPE_HHDLC },
297
298 /* RFC 2625 IP-over-Fibre Channel */
299 { DLT_IP_OVER_FC, LINKTYPE_IP_OVER_FC },
300
301 /* Solaris+SunATM */
302 { DLT_SUNATM, LINKTYPE_SUNATM },
303
304 /* RapidIO */
305 { DLT_RIO, LINKTYPE_RIO },
306
307 /* PCI Express */
308 { DLT_PCI_EXP, LINKTYPE_PCI_EXP },
309
310 /* Xilinx Aurora link layer */
311 { DLT_AURORA, LINKTYPE_AURORA },
312
313 /* 802.11 plus WLAN header */
314 { DLT_IEEE802_11_RADIO, LINKTYPE_IEEE802_11_RADIO },
315
316 /* Tazmen Sniffer Protocol */
317 { DLT_TZSP, LINKTYPE_TZSP },
318
319 /* Arcnet with Linux-style link-layer headers */
320 { DLT_ARCNET_LINUX, LINKTYPE_ARCNET_LINUX },
321
322 /* Juniper-internal chassis encapsulation */
323 { DLT_JUNIPER_MLPPP, LINKTYPE_JUNIPER_MLPPP },
324 { DLT_JUNIPER_MLFR, LINKTYPE_JUNIPER_MLFR },
325 { DLT_JUNIPER_ES, LINKTYPE_JUNIPER_ES },
326 { DLT_JUNIPER_GGSN, LINKTYPE_JUNIPER_GGSN },
327 { DLT_JUNIPER_MFR, LINKTYPE_JUNIPER_MFR },
328 { DLT_JUNIPER_ATM2, LINKTYPE_JUNIPER_ATM2 },
329 { DLT_JUNIPER_SERVICES, LINKTYPE_JUNIPER_SERVICES },
330 { DLT_JUNIPER_ATM1, LINKTYPE_JUNIPER_ATM1 },
331
332 /* Apple IP-over-IEEE 1394 cooked header */
333 { DLT_APPLE_IP_OVER_IEEE1394, LINKTYPE_APPLE_IP_OVER_IEEE1394 },
334
335 /* DOCSIS MAC frames */
336 { DLT_DOCSIS, LINKTYPE_DOCSIS },
337
338 /*
339 * Any platform that defines additional DLT_* codes should:
340 *
341 * request a LINKTYPE_* code and value from tcpdump.org,
342 * as per the above;
343 *
344 * add, in their version of libpcap, an entry to map
345 * those DLT_* codes to the corresponding LINKTYPE_*
346 * code;
347 *
348 * redefine, in their "net/bpf.h", any DLT_* values
349 * that collide with the values used by their additional
350 * DLT_* codes, to remove those collisions (but without
351 * making them collide with any of the LINKTYPE_*
352 * values equal to 50 or above; they should also avoid
353 * defining DLT_* values that collide with those
354 * LINKTYPE_* values, either).
355 */
356 { -1, -1 }
357 };
358
359 static int
360 dlt_to_linktype(int dlt)
361 {
362 int i;
363
364 for (i = 0; map[i].dlt != -1; i++) {
365 if (map[i].dlt == dlt)
366 return (map[i].linktype);
367 }
368
369 /*
370 * If we don't have a mapping for this DLT_ code, return an
371 * error; that means that the table above needs to have an
372 * entry added.
373 */
374 return (-1);
375 }
376
377 static int
378 linktype_to_dlt(int linktype)
379 {
380 int i;
381
382 for (i = 0; map[i].linktype != -1; i++) {
383 if (map[i].linktype == linktype)
384 return (map[i].dlt);
385 }
386
387 /*
388 * If we don't have an entry for this link type, return
389 * the link type value; it may be a DLT_ value from an
390 * older version of libpcap.
391 */
392 return linktype;
393 }
394
395 static int
396 sf_write_header(FILE *fp, int linktype, int thiszone, int snaplen)
397 {
398 struct pcap_file_header hdr;
399
400 hdr.magic = TCPDUMP_MAGIC;
401 hdr.version_major = PCAP_VERSION_MAJOR;
402 hdr.version_minor = PCAP_VERSION_MINOR;
403
404 hdr.thiszone = thiszone;
405 hdr.snaplen = snaplen;
406 hdr.sigfigs = 0;
407 hdr.linktype = linktype;
408
409 if (fwrite((char *)&hdr, sizeof(hdr), 1, fp) != 1)
410 return (-1);
411
412 return (0);
413 }
414
415 static void
416 swap_hdr(struct pcap_file_header *hp)
417 {
418 hp->version_major = SWAPSHORT(hp->version_major);
419 hp->version_minor = SWAPSHORT(hp->version_minor);
420 hp->thiszone = SWAPLONG(hp->thiszone);
421 hp->sigfigs = SWAPLONG(hp->sigfigs);
422 hp->snaplen = SWAPLONG(hp->snaplen);
423 hp->linktype = SWAPLONG(hp->linktype);
424 }
425
426 static int
427 sf_stats(pcap_t *p, struct pcap_stat *ps)
428 {
429 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
430 "Statistics aren't available from savefiles");
431 return (-1);
432 }
433
434 static void
435 sf_close(pcap_t *p)
436 {
437 if (p->sf.rfile != stdin)
438 (void)fclose(p->sf.rfile);
439 if (p->sf.base != NULL)
440 free(p->sf.base);
441 }
442
443 pcap_t *
444 pcap_open_offline(const char *fname, char *errbuf)
445 {
446 register pcap_t *p;
447 register FILE *fp;
448 struct pcap_file_header hdr;
449 bpf_u_int32 magic;
450 int linklen;
451
452 p = (pcap_t *)malloc(sizeof(*p));
453 if (p == NULL) {
454 strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
455 return (NULL);
456 }
457
458 memset((char *)p, 0, sizeof(*p));
459
460 if (fname[0] == '-' && fname[1] == '\0')
461 fp = stdin;
462 else {
463 #ifndef WIN32
464 fp = fopen(fname, "r");
465 #else
466 fp = fopen(fname, "rb");
467 #endif
468 if (fp == NULL) {
469 snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname,
470 pcap_strerror(errno));
471 goto bad;
472 }
473 }
474 if (fread((char *)&hdr, sizeof(hdr), 1, fp) != 1) {
475 snprintf(errbuf, PCAP_ERRBUF_SIZE, "fread: %s",
476 pcap_strerror(errno));
477 goto bad;
478 }
479 magic = hdr.magic;
480 if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
481 magic = SWAPLONG(magic);
482 if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
483 snprintf(errbuf, PCAP_ERRBUF_SIZE,
484 "bad dump file format");
485 goto bad;
486 }
487 p->sf.swapped = 1;
488 swap_hdr(&hdr);
489 }
490 if (magic == PATCHED_TCPDUMP_MAGIC) {
491 /*
492 * XXX - the patch that's in some versions of libpcap
493 * changes the packet header but not the magic number;
494 * we'd have to use some hacks^H^H^H^H^Hheuristics to
495 * detect that.
496 */
497 p->sf.hdrsize = sizeof(struct pcap_sf_patched_pkthdr);
498 } else
499 p->sf.hdrsize = sizeof(struct pcap_sf_pkthdr);
500 if (hdr.version_major < PCAP_VERSION_MAJOR) {
501 snprintf(errbuf, PCAP_ERRBUF_SIZE, "archaic file format");
502 goto bad;
503 }
504 p->tzoff = hdr.thiszone;
505 p->snapshot = hdr.snaplen;
506 p->linktype = linktype_to_dlt(hdr.linktype);
507 p->sf.rfile = fp;
508 #ifndef WIN32
509 p->bufsize = hdr.snaplen;
510 #else
511 /* Allocate the space for pcap_pkthdr as well. It will be used by pcap_read_ex */
512 p->bufsize = hdr.snaplen+sizeof(struct pcap_pkthdr);
513 #endif
514
515 /* Align link header as required for proper data alignment */
516 /* XXX should handle all types */
517 switch (p->linktype) {
518
519 case DLT_EN10MB:
520 linklen = 14;
521 break;
522
523 case DLT_FDDI:
524 linklen = 13 + 8; /* fddi_header + llc */
525 break;
526
527 case DLT_NULL:
528 default:
529 linklen = 0;
530 break;
531 }
532
533 if (p->bufsize < 0)
534 p->bufsize = BPF_MAXBUFSIZE;
535 p->sf.base = (u_char *)malloc(p->bufsize + BPF_ALIGNMENT);
536 if (p->sf.base == NULL) {
537 strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
538 goto bad;
539 }
540 p->buffer = p->sf.base + BPF_ALIGNMENT - (linklen % BPF_ALIGNMENT);
541 p->sf.version_major = hdr.version_major;
542 p->sf.version_minor = hdr.version_minor;
543 #ifdef PCAP_FDDIPAD
544 /* XXX padding only needed for kernel fcode */
545 pcap_fddipad = 0;
546 #endif
547
548 /*
549 * We interchanged the caplen and len fields at version 2.3,
550 * in order to match the bpf header layout. But unfortunately
551 * some files were written with version 2.3 in their headers
552 * but without the interchanged fields.
553 *
554 * In addition, DG/UX tcpdump writes out files with a version
555 * number of 543.0, and with the caplen and len fields in the
556 * pre-2.3 order.
557 */
558 switch (hdr.version_major) {
559
560 case 2:
561 if (hdr.version_minor < 3)
562 p->sf.lengths_swapped = SWAPPED;
563 else if (hdr.version_minor == 3)
564 p->sf.lengths_swapped = MAYBE_SWAPPED;
565 else
566 p->sf.lengths_swapped = NOT_SWAPPED;
567 break;
568
569 case 543:
570 p->sf.lengths_swapped = SWAPPED;
571 break;
572
573 default:
574 p->sf.lengths_swapped = NOT_SWAPPED;
575 break;
576 }
577
578 p->read_op = pcap_offline_read;
579 p->setfilter_op = install_bpf_program;
580 p->set_datalink_op = NULL; /* we don't support munging link-layer headers */
581 p->stats_op = sf_stats;
582 p->close_op = sf_close;
583
584 return (p);
585 bad:
586 if(fp)
587 fclose(fp);
588 free(p);
589 return (NULL);
590 }
591
592 /*
593 * Read sf_readfile and return the next packet. Return the header in hdr
594 * and the contents in buf. Return 0 on success, SFERR_EOF if there were
595 * no more packets, and SFERR_TRUNC if a partial packet was encountered.
596 */
597 static int
598 sf_next_packet(pcap_t *p, struct pcap_pkthdr *hdr, u_char *buf, u_int buflen)
599 {
600 struct pcap_sf_patched_pkthdr sf_hdr;
601 FILE *fp = p->sf.rfile;
602 size_t amt_read;
603 bpf_u_int32 t;
604
605 /*
606 * Read the packet header; the structure we use as a buffer
607 * is the longer structure for files generated by the patched
608 * libpcap, but if the file has the magic number for an
609 * unpatched libpcap we only read as many bytes as the regular
610 * header has.
611 */
612 amt_read = fread(&sf_hdr, 1, p->sf.hdrsize, fp);
613 if (amt_read != p->sf.hdrsize) {
614 if (ferror(fp)) {
615 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
616 "error reading dump file: %s",
617 pcap_strerror(errno));
618 return (-1);
619 } else {
620 if (amt_read != 0) {
621 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
622 "truncated dump file; tried to read %d header bytes, only got %lu",
623 p->sf.hdrsize, (unsigned long)amt_read);
624 return (-1);
625 }
626 /* EOF */
627 return (1);
628 }
629 }
630
631 if (p->sf.swapped) {
632 /* these were written in opposite byte order */
633 hdr->caplen = SWAPLONG(sf_hdr.caplen);
634 hdr->len = SWAPLONG(sf_hdr.len);
635 hdr->ts.tv_sec = SWAPLONG(sf_hdr.ts.tv_sec);
636 hdr->ts.tv_usec = SWAPLONG(sf_hdr.ts.tv_usec);
637 } else {
638 hdr->caplen = sf_hdr.caplen;
639 hdr->len = sf_hdr.len;
640 hdr->ts.tv_sec = sf_hdr.ts.tv_sec;
641 hdr->ts.tv_usec = sf_hdr.ts.tv_usec;
642 }
643 /* Swap the caplen and len fields, if necessary. */
644 switch (p->sf.lengths_swapped) {
645
646 case NOT_SWAPPED:
647 break;
648
649 case MAYBE_SWAPPED:
650 if (hdr->caplen <= hdr->len) {
651 /*
652 * The captured length is <= the actual length,
653 * so presumably they weren't swapped.
654 */
655 break;
656 }
657 /* FALLTHROUGH */
658
659 case SWAPPED:
660 t = hdr->caplen;
661 hdr->caplen = hdr->len;
662 hdr->len = t;
663 break;
664 }
665
666 if (hdr->caplen > buflen) {
667 /*
668 * This can happen due to Solaris 2.3 systems tripping
669 * over the BUFMOD problem and not setting the snapshot
670 * correctly in the savefile header. If the caplen isn't
671 * grossly wrong, try to salvage.
672 */
673 static u_char *tp = NULL;
674 static size_t tsize = 0;
675
676 if (hdr->caplen > 65535) {
677 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
678 "bogus savefile header");
679 return (-1);
680 }
681
682 if (tsize < hdr->caplen) {
683 tsize = ((hdr->caplen + 1023) / 1024) * 1024;
684 if (tp != NULL)
685 free((u_char *)tp);
686 tp = (u_char *)malloc(tsize);
687 if (tp == NULL) {
688 tsize = 0;
689 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
690 "BUFMOD hack malloc");
691 return (-1);
692 }
693 }
694 amt_read = fread((char *)tp, 1, hdr->caplen, fp);
695 if (amt_read != hdr->caplen) {
696 if (ferror(fp)) {
697 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
698 "error reading dump file: %s",
699 pcap_strerror(errno));
700 } else {
701 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
702 "truncated dump file; tried to read %u captured bytes, only got %lu",
703 hdr->caplen, (unsigned long)amt_read);
704 }
705 return (-1);
706 }
707 /*
708 * We can only keep up to buflen bytes. Since caplen > buflen
709 * is exactly how we got here, we know we can only keep the
710 * first buflen bytes and must drop the remainder. Adjust
711 * caplen accordingly, so we don't get confused later as
712 * to how many bytes we have to play with.
713 */
714 hdr->caplen = buflen;
715 memcpy((char *)buf, (char *)tp, buflen);
716
717 } else {
718 /* read the packet itself */
719 amt_read = fread((char *)buf, 1, hdr->caplen, fp);
720 if (amt_read != hdr->caplen) {
721 if (ferror(fp)) {
722 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
723 "error reading dump file: %s",
724 pcap_strerror(errno));
725 } else {
726 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
727 "truncated dump file; tried to read %u captured bytes, only got %lu",
728 hdr->caplen, (unsigned long)amt_read);
729 }
730 return (-1);
731 }
732 }
733 return (0);
734 }
735
736 /*
737 * Print out packets stored in the file initialized by sf_read_init().
738 * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
739 */
740 int
741 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
742 {
743 struct bpf_insn *fcode = p->fcode.bf_insns;
744 int status = 0;
745 int n = 0;
746
747 while (status == 0) {
748 struct pcap_pkthdr h;
749
750 /*
751 * Has "pcap_breakloop()" been called?
752 * If so, return immediately - if we haven't read any
753 * packets, clear the flag and return -2 to indicate
754 * that we were told to break out of the loop, otherwise
755 * leave the flag set, so that the *next* call will break
756 * out of the loop without having read any packets, and
757 * return the number of packets we've processed so far.
758 */
759 if (p->break_loop) {
760 if (n == 0) {
761 p->break_loop = 0;
762 return (-2);
763 } else
764 return (n);
765 }
766
767 status = sf_next_packet(p, &h, p->buffer, p->bufsize);
768 if (status) {
769 if (status == 1)
770 return (0);
771 return (status);
772 }
773
774 if (fcode == NULL ||
775 bpf_filter(fcode, p->buffer, h.len, h.caplen)) {
776 (*callback)(user, &h, p->buffer);
777 if (++n >= cnt && cnt > 0)
778 break;
779 }
780 }
781 /*XXX this breaks semantics tcpslice expects */
782 return (n);
783 }
784
785 /*
786 * Output a packet to the initialized dump file.
787 */
788 void
789 pcap_dump(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
790 {
791 register FILE *f;
792 struct pcap_sf_pkthdr sf_hdr;
793
794 f = (FILE *)user;
795 sf_hdr.ts.tv_sec = h->ts.tv_sec;
796 sf_hdr.ts.tv_usec = h->ts.tv_usec;
797 sf_hdr.caplen = h->caplen;
798 sf_hdr.len = h->len;
799 /* XXX we should check the return status */
800 (void)fwrite(&sf_hdr, sizeof(sf_hdr), 1, f);
801 (void)fwrite((char *)sp, h->caplen, 1, f);
802 }
803
804 /*
805 * Initialize so that sf_write() will output to the file named 'fname'.
806 */
807 pcap_dumper_t *
808 pcap_dump_open(pcap_t *p, const char *fname)
809 {
810 FILE *f;
811 int linktype;
812
813 linktype = dlt_to_linktype(p->linktype);
814 if (linktype == -1) {
815 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
816 "%s: link-layer type %d isn't supported in savefiles",
817 fname, linktype);
818 return (NULL);
819 }
820
821 if (fname[0] == '-' && fname[1] == '\0') {
822 f = stdout;
823 #ifdef WIN32
824 _setmode(_fileno(f), _O_BINARY);
825 #endif
826 } else {
827 #ifndef WIN32
828 f = fopen(fname, "w");
829 #else
830 f = fopen(fname, "wb");
831 setbuf(f, NULL); /* XXX - why? */
832 #endif
833 if (f == NULL) {
834 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
835 fname, pcap_strerror(errno));
836 return (NULL);
837 }
838 }
839 (void)sf_write_header(f, linktype, p->tzoff, p->snapshot);
840 return ((pcap_dumper_t *)f);
841 }
842
843 FILE *
844 pcap_dump_file(pcap_dumper_t *p)
845 {
846 return ((FILE *)p);
847 }
848
849 int
850 pcap_dump_flush(pcap_dumper_t *p)
851 {
852
853 if (fflush((FILE *)p) == EOF)
854 return (-1);
855 else
856 return (0);
857 }
858
859 void
860 pcap_dump_close(pcap_dumper_t *p)
861 {
862
863 #ifdef notyet
864 if (ferror((FILE *)p))
865 return-an-error;
866 /* XXX should check return from fclose() too */
867 #endif
868 (void)fclose((FILE *)p);
869 }
[mirror] the LIBpcap interface to various kernel packet capture mechanism