savefile.c revision 214518 
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
32static const char rcsid[] _U_ =
33    "@(#) $Header: /tcpdump/master/libpcap/savefile.c,v 1.183 2008-12-23 20:13:29 guy Exp $ (LBL)";
34#endif
35
36#ifdef HAVE_CONFIG_H
37#include "config.h"
38#endif
39
40#ifdef WIN32
41#include <pcap-stdinc.h>
42#else /* WIN32 */
43#if HAVE_INTTYPES_H
44#include <inttypes.h>
45#elif HAVE_STDINT_H
46#include <stdint.h>
47#endif
48#ifdef HAVE_SYS_BITYPES_H
49#include <sys/bitypes.h>
50#endif
51#include <sys/types.h>
52#endif /* WIN32 */
53
54#include <errno.h>
55#include <memory.h>
56#include <stdio.h>
57#include <stdlib.h>
58#include <string.h>
59
60#include "pcap-int.h"
61#include "pcap/usb.h"
62
63#ifdef HAVE_OS_PROTO_H
64#include "os-proto.h"
65#endif
66
67#include "sf-pcap.h"
68#include "sf-pcap-ng.h"
69
70/*
71 * Setting O_BINARY on DOS/Windows is a bit tricky
72 */
73#if defined(WIN32)
74  #define SET_BINMODE(f)  _setmode(_fileno(f), _O_BINARY)
75#elif defined(MSDOS)
76  #if defined(__HIGHC__)
77  #define SET_BINMODE(f)  setmode(f, O_BINARY)
78  #else
79  #define SET_BINMODE(f)  setmode(fileno(f), O_BINARY)
80  #endif
81#endif
82
83static int
84sf_getnonblock(pcap_t *p, char *errbuf)
85{
86	/*
87	 * This is a savefile, not a live capture file, so never say
88	 * it's in non-blocking mode.
89	 */
90	return (0);
91}
92
93static int
94sf_setnonblock(pcap_t *p, int nonblock, char *errbuf)
95{
96	/*
97	 * This is a savefile, not a live capture file, so ignore
98	 * requests to put it in non-blocking mode.
99	 */
100	return (0);
101}
102
103static int
104sf_stats(pcap_t *p, struct pcap_stat *ps)
105{
106	snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
107	    "Statistics aren't available from savefiles");
108	return (-1);
109}
110
111#ifdef WIN32
112static int
113sf_setbuff(pcap_t *p, int dim)
114{
115	snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
116	    "The kernel buffer size cannot be set while reading from a file");
117	return (-1);
118}
119
120static int
121sf_setmode(pcap_t *p, int mode)
122{
123	snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
124	    "impossible to set mode while reading from a file");
125	return (-1);
126}
127
128static int
129sf_setmintocopy(pcap_t *p, int size)
130{
131	snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
132	    "The mintocopy parameter cannot be set while reading from a file");
133	return (-1);
134}
135#endif
136
137static int
138sf_inject(pcap_t *p, const void *buf _U_, size_t size _U_)
139{
140	strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
141	    PCAP_ERRBUF_SIZE);
142	return (-1);
143}
144
145/*
146 * Set direction flag: Which packets do we accept on a forwarding
147 * single device? IN, OUT or both?
148 */
149static int
150sf_setdirection(pcap_t *p, pcap_direction_t d)
151{
152	snprintf(p->errbuf, sizeof(p->errbuf),
153	    "Setting direction is not supported on savefiles");
154	return (-1);
155}
156
157static void
158sf_cleanup(pcap_t *p)
159{
160	if (p->sf.rfile != stdin)
161		(void)fclose(p->sf.rfile);
162	if (p->buffer != NULL)
163		free(p->buffer);
164}
165
166pcap_t *
167pcap_open_offline(const char *fname, char *errbuf)
168{
169	FILE *fp;
170	pcap_t *p;
171
172	if (fname[0] == '-' && fname[1] == '\0')
173	{
174		fp = stdin;
175#if defined(WIN32) || defined(MSDOS)
176		/*
177		 * We're reading from the standard input, so put it in binary
178		 * mode, as savefiles are binary files.
179		 */
180		SET_BINMODE(fp);
181#endif
182	}
183	else {
184#if !defined(WIN32) && !defined(MSDOS)
185		fp = fopen(fname, "r");
186#else
187		fp = fopen(fname, "rb");
188#endif
189		if (fp == NULL) {
190			snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname,
191			    pcap_strerror(errno));
192			return (NULL);
193		}
194	}
195	p = pcap_fopen_offline(fp, errbuf);
196	if (p == NULL) {
197		if (fp != stdin)
198			fclose(fp);
199	}
200	return (p);
201}
202
203#ifdef WIN32
204pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf)
205{
206	int fd;
207	FILE *file;
208
209	fd = _open_osfhandle(osfd, _O_RDONLY);
210	if ( fd < 0 )
211	{
212		snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno));
213		return NULL;
214	}
215
216	file = _fdopen(fd, "rb");
217	if ( file == NULL )
218	{
219		snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno));
220		return NULL;
221	}
222
223	return pcap_fopen_offline(file, errbuf);
224}
225#endif
226
227static int (*check_headers[])(pcap_t *, bpf_u_int32, FILE *, char *) = {
228	pcap_check_header,
229	pcap_ng_check_header
230};
231
232#define	N_FILE_TYPES	(sizeof check_headers / sizeof check_headers[0])
233
234#ifdef WIN32
235static
236#endif
237pcap_t *
238pcap_fopen_offline(FILE *fp, char *errbuf)
239{
240	register pcap_t *p;
241	bpf_u_int32 magic;
242	size_t amt_read;
243	u_int i;
244
245	p = pcap_create_common("(savefile)", errbuf);
246	if (p == NULL)
247		return (NULL);
248
249	/*
250	 * Read the first 4 bytes of the file; the network analyzer dump
251	 * file formats we support (pcap and pcap-ng), and several other
252	 * formats we might support in the future (such as snoop, DOS and
253	 * Windows Sniffer, and Microsoft Network Monitor) all have magic
254	 * numbers that are unique in their first 4 bytes.
255	 */
256	amt_read = fread((char *)&magic, 1, sizeof(magic), fp);
257	if (amt_read != sizeof(magic)) {
258		if (ferror(fp)) {
259			snprintf(errbuf, PCAP_ERRBUF_SIZE,
260			    "error reading dump file: %s",
261			    pcap_strerror(errno));
262		} else {
263			snprintf(errbuf, PCAP_ERRBUF_SIZE,
264			    "truncated dump file; tried to read %lu file header bytes, only got %lu",
265			    (unsigned long)sizeof(magic),
266			    (unsigned long)amt_read);
267		}
268		goto bad;
269	}
270
271	/*
272	 * Try all file types.
273	 */
274	for (i = 0; i < N_FILE_TYPES; i++) {
275		switch ((*check_headers[i])(p, magic, fp, errbuf)) {
276
277		case -1:
278			/*
279			 * Error trying to read the header.
280			 */
281			goto bad;
282
283		case 1:
284			/*
285			 * Yup, that's it.
286			 */
287			goto found;
288		}
289	}
290
291	/*
292	 * Well, who knows what this mess is....
293	 */
294	snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format");
295	goto bad;
296
297found:
298	p->sf.rfile = fp;
299
300#ifdef PCAP_FDDIPAD
301	/* Padding only needed for live capture fcode */
302	p->fddipad = 0;
303#endif
304
305#if !defined(WIN32) && !defined(MSDOS)
306	/*
307	 * You can do "select()" and "poll()" on plain files on most
308	 * platforms, and should be able to do so on pipes.
309	 *
310	 * You can't do "select()" on anything other than sockets in
311	 * Windows, so, on Win32 systems, we don't have "selectable_fd".
312	 */
313	p->selectable_fd = fileno(fp);
314#endif
315
316	p->read_op = pcap_offline_read;
317	p->inject_op = sf_inject;
318	p->setfilter_op = install_bpf_program;
319	p->setdirection_op = sf_setdirection;
320	p->set_datalink_op = NULL;	/* we don't support munging link-layer headers */
321	p->getnonblock_op = sf_getnonblock;
322	p->setnonblock_op = sf_setnonblock;
323	p->stats_op = sf_stats;
324#ifdef WIN32
325	p->setbuff_op = sf_setbuff;
326	p->setmode_op = sf_setmode;
327	p->setmintocopy_op = sf_setmintocopy;
328#endif
329	p->cleanup_op = sf_cleanup;
330	p->activated = 1;
331
332	return (p);
333 bad:
334	free(p);
335	return (NULL);
336}
337
338/*
339 * Read packets from a capture file, and call the callback for each
340 * packet.
341 * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
342 */
343int
344pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
345{
346	struct bpf_insn *fcode;
347	int status = 0;
348	int n = 0;
349	u_char *data;
350
351	while (status == 0) {
352		struct pcap_pkthdr h;
353
354		/*
355		 * Has "pcap_breakloop()" been called?
356		 * If so, return immediately - if we haven't read any
357		 * packets, clear the flag and return -2 to indicate
358		 * that we were told to break out of the loop, otherwise
359		 * leave the flag set, so that the *next* call will break
360		 * out of the loop without having read any packets, and
361		 * return the number of packets we've processed so far.
362		 */
363		if (p->break_loop) {
364			if (n == 0) {
365				p->break_loop = 0;
366				return (-2);
367			} else
368				return (n);
369		}
370
371		status = p->sf.next_packet_op(p, &h, &data);
372		if (status) {
373			if (status == 1)
374				return (0);
375			return (status);
376		}
377
378		if ((fcode = p->fcode.bf_insns) == NULL ||
379		    bpf_filter(fcode, p->buffer, h.len, h.caplen)) {
380			(*callback)(user, &h, data);
381			if (++n >= cnt && cnt > 0)
382				break;
383		}
384	}
385	/*XXX this breaks semantics tcpslice expects */
386	return (n);
387}
388