2 * Copyright (c) 1993, 1994, 1995, 1996, 1997
3 * The Regents of the University of California. All rights reserved.
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
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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
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.
21 * savefile.c - supports offline use of tcpdump
22 * Extraction/creation by Jeffrey Mogul, DECWRL
23 * Modified by Steve McCanne, LBL.
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.
35 #include <pcap-types.h>
46 #include <limits.h> /* for INT_MAX */
50 #ifdef HAVE_OS_PROTO_H
55 #include "sf-pcapng.h"
56 #include "pcap-common.h"
61 * This isn't exported on Windows, because it would only work if both
62 * WinPcap/Npcap and the code using it were to use the Universal CRT; otherwise,
63 * a FILE structure in WinPcap/Npcap and a FILE structure in the code using it
64 * could be different if they're using different versions of the C runtime.
66 * Instead, pcap/pcap.h defines it as a macro that wraps the hopen version,
67 * with the wrapper calling _fileno() and _get_osfhandle() themselves,
68 * so that it convert the appropriate CRT version's FILE structure to
69 * a HANDLE (which is OS-defined, not CRT-defined, and is part of the Win32
72 static pcap_t *pcap_fopen_offline_with_tstamp_precision(FILE *, u_int, char *);
76 * Setting O_BINARY on DOS/Windows is a bit tricky
79 #define SET_BINMODE(f) _setmode(_fileno(f), _O_BINARY)
81 #if defined(__HIGHC__)
82 #define SET_BINMODE(f) setmode(f, O_BINARY)
84 #define SET_BINMODE(f) setmode(fileno(f), O_BINARY)
89 sf_getnonblock(pcap_t *p _U_)
92 * This is a savefile, not a live capture file, so never say
93 * it's in non-blocking mode.
99 sf_setnonblock(pcap_t *p, int nonblock _U_)
102 * This is a savefile, not a live capture file, so reject
103 * requests to put it in non-blocking mode. (If it's a
104 * pipe, it could be put in non-blocking mode, but that
105 * would significantly complicate the code to read packets,
106 * as it would have to handle reading partial packets and
107 * keeping the state of the read.)
109 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
110 "Savefiles cannot be put into non-blocking mode");
115 sf_cant_set_rfmon(pcap_t *p _U_)
118 * This is a savefile, not a device on which you can capture,
119 * so never say it supports being put into monitor mode.
125 sf_stats(pcap_t *p, struct pcap_stat *ps _U_)
127 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
128 "Statistics aren't available from savefiles");
133 static struct pcap_stat *
134 sf_stats_ex(pcap_t *p, int *size _U_)
136 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
137 "Statistics aren't available from savefiles");
142 sf_setbuff(pcap_t *p, int dim _U_)
144 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
145 "The kernel buffer size cannot be set while reading from a file");
150 sf_setmode(pcap_t *p, int mode _U_)
152 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
153 "impossible to set mode while reading from a file");
158 sf_setmintocopy(pcap_t *p, int size _U_)
160 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
161 "The mintocopy parameter cannot be set while reading from a file");
166 sf_getevent(pcap_t *pcap)
168 (void)snprintf(pcap->errbuf, sizeof(pcap->errbuf),
169 "The read event cannot be retrieved while reading from a file");
170 return (INVALID_HANDLE_VALUE);
174 sf_oid_get_request(pcap_t *p, bpf_u_int32 oid _U_, void *data _U_,
177 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
178 "An OID get request cannot be performed on a file");
183 sf_oid_set_request(pcap_t *p, bpf_u_int32 oid _U_, const void *data _U_,
186 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
187 "An OID set request cannot be performed on a file");
192 sf_sendqueue_transmit(pcap_t *p, pcap_send_queue *queue _U_, int sync _U_)
194 pcap_strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
200 sf_setuserbuffer(pcap_t *p, int size _U_)
202 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
203 "The user buffer cannot be set when reading from a file");
208 sf_live_dump(pcap_t *p, char *filename _U_, int maxsize _U_, int maxpacks _U_)
210 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
211 "Live packet dumping cannot be performed when reading from a file");
216 sf_live_dump_ended(pcap_t *p, int sync _U_)
218 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
219 "Live packet dumping cannot be performed on a pcap_open_dead pcap_t");
223 static PAirpcapHandle
224 sf_get_airpcap_handle(pcap_t *pcap _U_)
231 sf_inject(pcap_t *p, const void *buf _U_, int size _U_)
233 pcap_strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
239 * Set direction flag: Which packets do we accept on a forwarding
240 * single device? IN, OUT or both?
243 sf_setdirection(pcap_t *p, pcap_direction_t d _U_)
245 snprintf(p->errbuf, sizeof(p->errbuf),
246 "Setting direction is not supported on savefiles");
251 sf_cleanup(pcap_t *p)
253 if (p->rfile != stdin)
254 (void)fclose(p->rfile);
255 if (p->buffer != NULL)
257 pcap_freecode(&p->fcode);
262 * Wrapper for fopen() and _wfopen().
264 * If we're in UTF-8 mode, map the pathname from UTF-8 to UTF-16LE and
267 * If we're not, just use fopen(); that'll treat it as being in the
271 charset_fopen(const char *path, const char *mode)
274 #define MAX_MODE_LEN 16
275 wchar_t utf16_mode[MAX_MODE_LEN+1];
281 if (pcap_utf_8_mode) {
283 * Map from UTF-8 to UTF-16LE.
284 * Fail if there are invalid characters in the input
285 * string, rather than converting them to REPLACEMENT
286 * CHARACTER; the latter is appropriate for strings
287 * to be displayed to the user, but for file names
288 * you just want the attempt to open the file to fail.
290 utf16_path = cp_to_utf_16le(CP_UTF8, path,
291 MB_ERR_INVALID_CHARS);
292 if (utf16_path == NULL) {
294 * Error. Assume errno has been set.
296 * XXX - what about Windows errors?
302 * Now convert the mode to UTF-16LE as well.
303 * We assume the mode is ASCII, and that
304 * it's short, so that's easy.
306 for (i = 0; (c = *mode) != '\0'; i++, mode++) {
308 /* Not an ASCII character; fail with EINVAL. */
313 if (i >= MAX_MODE_LEN) {
314 /* The mode string is longer than we allow. */
321 utf16_mode[i] = '\0';
324 * OK, we have UTF-16LE strings; hand them to
327 fp = _wfopen(utf16_path, utf16_mode);
330 * Make sure freeing the UTF-16LE string doesn't
331 * overwrite the error code we got from _wfopen().
340 * This takes strings in the local code page as an
343 return (fopen(path, mode));
349 pcap_open_offline_with_tstamp_precision(const char *fname, u_int precision,
356 snprintf(errbuf, PCAP_ERRBUF_SIZE,
357 "A null pointer was supplied as the file name");
360 if (fname[0] == '-' && fname[1] == '\0')
364 snprintf(errbuf, PCAP_ERRBUF_SIZE,
365 "The standard input is not open");
368 #if defined(_WIN32) || defined(MSDOS)
370 * We're reading from the standard input, so put it in binary
371 * mode, as savefiles are binary files.
378 * Use charset_fopen(); on Windows, it tests whether we're
379 * in "local code page" or "UTF-8" mode, and treats the
380 * pathname appropriately, and on other platforms, it just
383 * "b" is supported as of C90, so *all* UN*Xes should
384 * support it, even though it does nothing. For MS-DOS,
387 fp = charset_fopen(fname, "rb");
389 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
394 p = pcap_fopen_offline_with_tstamp_precision(fp, precision, errbuf);
403 pcap_open_offline(const char *fname, char *errbuf)
405 return (pcap_open_offline_with_tstamp_precision(fname,
406 PCAP_TSTAMP_PRECISION_MICRO, errbuf));
410 pcap_t* pcap_hopen_offline_with_tstamp_precision(intptr_t osfd, u_int precision,
416 fd = _open_osfhandle(osfd, _O_RDONLY);
419 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
420 errno, "_open_osfhandle");
424 file = _fdopen(fd, "rb");
427 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
433 return pcap_fopen_offline_with_tstamp_precision(file, precision,
437 pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf)
439 return pcap_hopen_offline_with_tstamp_precision(osfd,
440 PCAP_TSTAMP_PRECISION_MICRO, errbuf);
445 * Given a link-layer header type and snapshot length, return a
446 * snapshot length to use when reading the file; it's guaranteed
447 * to be > 0 and <= INT_MAX.
449 * XXX - the only reason why we limit it to <= INT_MAX is so that
450 * it fits in p->snapshot, and the only reason that p->snapshot is
451 * signed is that pcap_snapshot() returns an int, not an unsigned int.
454 pcap_adjust_snapshot(bpf_u_int32 linktype, bpf_u_int32 snaplen)
456 if (snaplen == 0 || snaplen > INT_MAX) {
458 * Bogus snapshot length; use the maximum for this
459 * link-layer type as a fallback.
461 * XXX - we don't clamp snapshot lengths that are
462 * <= INT_MAX but > max_snaplen_for_dlt(linktype),
463 * so a capture file could cause us to allocate
464 * a Really Big Buffer.
466 snaplen = max_snaplen_for_dlt(linktype);
471 static pcap_t *(*check_headers[])(const uint8_t *, FILE *, u_int, char *, int *) = {
476 #define N_FILE_TYPES (sizeof check_headers / sizeof check_headers[0])
482 pcap_fopen_offline_with_tstamp_precision(FILE *fp, u_int precision,
492 * Fail if we were passed a NULL fp.
494 * That shouldn't happen if we're opening with a path name, but
495 * it could happen if buggy code is opening with a FILE * and
496 * didn't bother to make sure the FILE * isn't null.
499 snprintf(errbuf, PCAP_ERRBUF_SIZE,
500 "Null FILE * pointer provided to savefile open routine");
505 * Read the first 4 bytes of the file; the network analyzer dump
506 * file formats we support (pcap and pcapng), and several other
507 * formats we might support in the future (such as snoop, DOS and
508 * Windows Sniffer, and Microsoft Network Monitor) all have magic
509 * numbers that are unique in their first 4 bytes.
511 amt_read = fread(&magic, 1, sizeof(magic), fp);
512 if (amt_read != sizeof(magic)) {
514 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
515 errno, "error reading dump file");
517 snprintf(errbuf, PCAP_ERRBUF_SIZE,
518 "truncated dump file; tried to read %zu file header bytes, only got %zu",
519 sizeof(magic), amt_read);
525 * Try all file types.
527 for (i = 0; i < N_FILE_TYPES; i++) {
528 p = (*check_headers[i])(magic, fp, precision, errbuf, &err);
530 /* Yup, that's it. */
535 * Error trying to read the header.
542 * Well, who knows what this mess is....
544 snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format");
550 /* Padding only needed for live capture fcode */
553 #if !defined(_WIN32) && !defined(MSDOS)
555 * You can do "select()" and "poll()" on plain files on most
556 * platforms, and should be able to do so on pipes.
558 * You can't do "select()" on anything other than sockets in
559 * Windows, so, on Win32 systems, we don't have "selectable_fd".
561 p->selectable_fd = fileno(fp);
564 p->can_set_rfmon_op = sf_cant_set_rfmon;
565 p->read_op = pcap_offline_read;
566 p->inject_op = sf_inject;
567 p->setfilter_op = install_bpf_program;
568 p->setdirection_op = sf_setdirection;
569 p->set_datalink_op = NULL; /* we don't support munging link-layer headers */
570 p->getnonblock_op = sf_getnonblock;
571 p->setnonblock_op = sf_setnonblock;
572 p->stats_op = sf_stats;
574 p->stats_ex_op = sf_stats_ex;
575 p->setbuff_op = sf_setbuff;
576 p->setmode_op = sf_setmode;
577 p->setmintocopy_op = sf_setmintocopy;
578 p->getevent_op = sf_getevent;
579 p->oid_get_request_op = sf_oid_get_request;
580 p->oid_set_request_op = sf_oid_set_request;
581 p->sendqueue_transmit_op = sf_sendqueue_transmit;
582 p->setuserbuffer_op = sf_setuserbuffer;
583 p->live_dump_op = sf_live_dump;
584 p->live_dump_ended_op = sf_live_dump_ended;
585 p->get_airpcap_handle_op = sf_get_airpcap_handle;
589 * For offline captures, the standard one-shot callback can
590 * be used for pcap_next()/pcap_next_ex().
592 p->oneshot_callback = pcap_oneshot;
595 * Default breakloop operation.
597 p->breakloop_op = pcap_breakloop_common;
600 * Savefiles never require special BPF code generation.
602 p->bpf_codegen_flags = 0;
610 * This isn't needed on Windows; we #define pcap_fopen_offline() as
611 * a wrapper around pcap_hopen_offline(), and we don't call it from
612 * inside this file, so it's unused.
616 pcap_fopen_offline(FILE *fp, char *errbuf)
618 return (pcap_fopen_offline_with_tstamp_precision(fp,
619 PCAP_TSTAMP_PRECISION_MICRO, errbuf));
624 * Read packets from a capture file, and call the callback for each
626 * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
629 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
631 struct bpf_insn *fcode;
636 * This can conceivably process more than INT_MAX packets,
637 * which would overflow the packet count, causing it either
638 * to look like a negative number, and thus cause us to
639 * return a value that looks like an error, or overflow
640 * back into positive territory, and thus cause us to
641 * return a too-low count.
643 * Therefore, if the packet count is unlimited, we clip
644 * it at INT_MAX; this routine is not expected to
645 * process packets indefinitely, so that's not an issue.
647 if (PACKET_COUNT_IS_UNLIMITED(cnt))
651 struct pcap_pkthdr h;
655 * Has "pcap_breakloop()" been called?
656 * If so, return immediately - if we haven't read any
657 * packets, clear the flag and return -2 to indicate
658 * that we were told to break out of the loop, otherwise
659 * leave the flag set, so that the *next* call will break
660 * out of the loop without having read any packets, and
661 * return the number of packets we've processed so far.
671 status = p->next_packet_op(p, &h, &data);
674 * Error. Pass it back to the caller.
680 * EOF. Nothing more to process;
686 * OK, we've read a packet; run it through the filter
687 * and, if it passes, process it.
689 if ((fcode = p->fcode.bf_insns) == NULL ||
690 pcap_filter(fcode, data, h.len, h.caplen)) {
691 (*callback)(user, &h, data);
692 n++; /* count the packet */
697 /*XXX this breaks semantics tcpslice expects */