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 #ifdef HAVE_CONFIG_H
32 #include "config.h"
33 #endif
34
35 #ifdef WIN32
36 #include <pcap-stdinc.h>
37 #else /* WIN32 */
38 #if HAVE_INTTYPES_H
39 #include <inttypes.h>
40 #elif HAVE_STDINT_H
41 #include <stdint.h>
42 #endif
43 #ifdef HAVE_SYS_BITYPES_H
44 #include <sys/bitypes.h>
45 #endif
46 #include <sys/types.h>
47 #endif /* WIN32 */
48
49 #include <errno.h>
50 #include <memory.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54
55 #include "pcap-int.h"
56 #include "pcap/usb.h"
57
58 #ifdef HAVE_OS_PROTO_H
59 #include "os-proto.h"
60 #endif
61
62 #include "sf-pcap.h"
63 #include "sf-pcap-ng.h"
64
65 /*
66 * Setting O_BINARY on DOS/Windows is a bit tricky
67 */
68 #if defined(WIN32)
69 #define SET_BINMODE(f) _setmode(_fileno(f), _O_BINARY)
70 #elif defined(MSDOS)
71 #if defined(__HIGHC__)
72 #define SET_BINMODE(f) setmode(f, O_BINARY)
73 #else
74 #define SET_BINMODE(f) setmode(fileno(f), O_BINARY)
75 #endif
76 #endif
77
78 static int
sf_getnonblock(pcap_t * p,char * errbuf)79 sf_getnonblock(pcap_t *p, char *errbuf)
80 {
81 /*
82 * This is a savefile, not a live capture file, so never say
83 * it's in non-blocking mode.
84 */
85 return (0);
86 }
87
88 static int
sf_setnonblock(pcap_t * p,int nonblock,char * errbuf)89 sf_setnonblock(pcap_t *p, int nonblock, char *errbuf)
90 {
91 /*
92 * This is a savefile, not a live capture file, so reject
93 * requests to put it in non-blocking mode. (If it's a
94 * pipe, it could be put in non-blocking mode, but that
95 * would significantly complicate the code to read packets,
96 * as it would have to handle reading partial packets and
97 * keeping the state of the read.)
98 */
99 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
100 "Savefiles cannot be put into non-blocking mode");
101 return (-1);
102 }
103
104 static int
sf_stats(pcap_t * p,struct pcap_stat * ps)105 sf_stats(pcap_t *p, struct pcap_stat *ps)
106 {
107 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
108 "Statistics aren't available from savefiles");
109 return (-1);
110 }
111
112 #ifdef WIN32
113 static int
sf_setbuff(pcap_t * p,int dim)114 sf_setbuff(pcap_t *p, int dim)
115 {
116 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
117 "The kernel buffer size cannot be set while reading from a file");
118 return (-1);
119 }
120
121 static int
sf_setmode(pcap_t * p,int mode)122 sf_setmode(pcap_t *p, int mode)
123 {
124 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
125 "impossible to set mode while reading from a file");
126 return (-1);
127 }
128
129 static int
sf_setmintocopy(pcap_t * p,int size)130 sf_setmintocopy(pcap_t *p, int size)
131 {
132 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
133 "The mintocopy parameter cannot be set while reading from a file");
134 return (-1);
135 }
136 #endif
137
138 static int
sf_inject(pcap_t * p,const void * buf _U_,size_t size _U_)139 sf_inject(pcap_t *p, const void *buf _U_, size_t size _U_)
140 {
141 strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
142 PCAP_ERRBUF_SIZE);
143 return (-1);
144 }
145
146 /*
147 * Set direction flag: Which packets do we accept on a forwarding
148 * single device? IN, OUT or both?
149 */
150 static int
sf_setdirection(pcap_t * p,pcap_direction_t d)151 sf_setdirection(pcap_t *p, pcap_direction_t d)
152 {
153 snprintf(p->errbuf, sizeof(p->errbuf),
154 "Setting direction is not supported on savefiles");
155 return (-1);
156 }
157
158 void
sf_cleanup(pcap_t * p)159 sf_cleanup(pcap_t *p)
160 {
161 if (p->rfile != stdin)
162 (void)fclose(p->rfile);
163 if (p->buffer != NULL)
164 free(p->buffer);
165 pcap_freecode(&p->fcode);
166 }
167
168 pcap_t *
pcap_open_offline_with_tstamp_precision(const char * fname,u_int precision,char * errbuf)169 pcap_open_offline_with_tstamp_precision(const char *fname, u_int precision,
170 char *errbuf)
171 {
172 FILE *fp;
173 pcap_t *p;
174
175 if (fname[0] == '-' && fname[1] == '\0')
176 {
177 fp = stdin;
178 #if defined(WIN32) || defined(MSDOS)
179 /*
180 * We're reading from the standard input, so put it in binary
181 * mode, as savefiles are binary files.
182 */
183 SET_BINMODE(fp);
184 #endif
185 }
186 else {
187 #if !defined(WIN32) && !defined(MSDOS)
188 fp = fopen(fname, "r");
189 #else
190 fp = fopen(fname, "rb");
191 #endif
192 if (fp == NULL) {
193 snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname,
194 pcap_strerror(errno));
195 return (NULL);
196 }
197 }
198 p = pcap_fopen_offline_with_tstamp_precision(fp, precision, errbuf);
199 if (p == NULL) {
200 if (fp != stdin)
201 fclose(fp);
202 }
203 return (p);
204 }
205
206 pcap_t *
pcap_open_offline(const char * fname,char * errbuf)207 pcap_open_offline(const char *fname, char *errbuf)
208 {
209 return (pcap_open_offline_with_tstamp_precision(fname,
210 PCAP_TSTAMP_PRECISION_MICRO, errbuf));
211 }
212
213 #ifdef WIN32
pcap_hopen_offline_with_tstamp_precision(intptr_t osfd,u_int precision,char * errbuf)214 pcap_t* pcap_hopen_offline_with_tstamp_precision(intptr_t osfd, u_int precision,
215 char *errbuf)
216 {
217 int fd;
218 FILE *file;
219
220 fd = _open_osfhandle(osfd, _O_RDONLY);
221 if ( fd < 0 )
222 {
223 snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno));
224 return NULL;
225 }
226
227 file = _fdopen(fd, "rb");
228 if ( file == NULL )
229 {
230 snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno));
231 return NULL;
232 }
233
234 return pcap_fopen_offline_with_tstamp_precision(file, precision,
235 errbuf);
236 }
237
pcap_hopen_offline(intptr_t osfd,char * errbuf)238 pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf)
239 {
240 return pcap_hopen_offline_with_tstamp_precision(osfd,
241 PCAP_TSTAMP_PRECISION_MICRO, errbuf);
242 }
243 #endif
244
245 static pcap_t *(*check_headers[])(bpf_u_int32, FILE *, u_int, char *, int *) = {
246 pcap_check_header,
247 pcap_ng_check_header
248 };
249
250 #define N_FILE_TYPES (sizeof check_headers / sizeof check_headers[0])
251
252 #ifdef WIN32
253 static
254 #endif
255 pcap_t *
pcap_fopen_offline_with_tstamp_precision(FILE * fp,u_int precision,char * errbuf)256 pcap_fopen_offline_with_tstamp_precision(FILE *fp, u_int precision,
257 char *errbuf)
258 {
259 register pcap_t *p;
260 bpf_u_int32 magic;
261 size_t amt_read;
262 u_int i;
263 int err;
264
265 /*
266 * Read the first 4 bytes of the file; the network analyzer dump
267 * file formats we support (pcap and pcap-ng), and several other
268 * formats we might support in the future (such as snoop, DOS and
269 * Windows Sniffer, and Microsoft Network Monitor) all have magic
270 * numbers that are unique in their first 4 bytes.
271 */
272 amt_read = fread((char *)&magic, 1, sizeof(magic), fp);
273 if (amt_read != sizeof(magic)) {
274 if (ferror(fp)) {
275 snprintf(errbuf, PCAP_ERRBUF_SIZE,
276 "error reading dump file: %s",
277 pcap_strerror(errno));
278 } else {
279 snprintf(errbuf, PCAP_ERRBUF_SIZE,
280 "truncated dump file; tried to read %lu file header bytes, only got %lu",
281 (unsigned long)sizeof(magic),
282 (unsigned long)amt_read);
283 }
284 return (NULL);
285 }
286
287 /*
288 * Try all file types.
289 */
290 for (i = 0; i < N_FILE_TYPES; i++) {
291 p = (*check_headers[i])(magic, fp, precision, errbuf, &err);
292 if (p != NULL) {
293 /* Yup, that's it. */
294 goto found;
295 }
296 if (err) {
297 /*
298 * Error trying to read the header.
299 */
300 return (NULL);
301 }
302 }
303
304 /*
305 * Well, who knows what this mess is....
306 */
307 snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format");
308 return (NULL);
309
310 found:
311 p->rfile = fp;
312
313 /* Padding only needed for live capture fcode */
314 p->fddipad = 0;
315
316 #if !defined(WIN32) && !defined(MSDOS)
317 /*
318 * You can do "select()" and "poll()" on plain files on most
319 * platforms, and should be able to do so on pipes.
320 *
321 * You can't do "select()" on anything other than sockets in
322 * Windows, so, on Win32 systems, we don't have "selectable_fd".
323 */
324 p->selectable_fd = fileno(fp);
325 #endif
326
327 p->read_op = pcap_offline_read;
328 p->inject_op = sf_inject;
329 p->setfilter_op = install_bpf_program;
330 p->setdirection_op = sf_setdirection;
331 p->set_datalink_op = NULL; /* we don't support munging link-layer headers */
332 p->getnonblock_op = sf_getnonblock;
333 p->setnonblock_op = sf_setnonblock;
334 p->stats_op = sf_stats;
335 #ifdef WIN32
336 p->setbuff_op = sf_setbuff;
337 p->setmode_op = sf_setmode;
338 p->setmintocopy_op = sf_setmintocopy;
339 #endif
340
341 /*
342 * For offline captures, the standard one-shot callback can
343 * be used for pcap_next()/pcap_next_ex().
344 */
345 p->oneshot_callback = pcap_oneshot;
346
347 /*
348 * Savefiles never require special BPF code generation.
349 */
350 p->bpf_codegen_flags = 0;
351
352 p->activated = 1;
353
354 return (p);
355 }
356
357 #ifdef WIN32
358 static
359 #endif
360 pcap_t *
pcap_fopen_offline(FILE * fp,char * errbuf)361 pcap_fopen_offline(FILE *fp, char *errbuf)
362 {
363 return (pcap_fopen_offline_with_tstamp_precision(fp,
364 PCAP_TSTAMP_PRECISION_MICRO, errbuf));
365 }
366
367 /*
368 * Read packets from a capture file, and call the callback for each
369 * packet.
370 * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
371 */
372 int
pcap_offline_read(pcap_t * p,int cnt,pcap_handler callback,u_char * user)373 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
374 {
375 struct bpf_insn *fcode;
376 int status = 0;
377 int n = 0;
378 u_char *data;
379
380 while (status == 0) {
381 struct pcap_pkthdr h;
382
383 /*
384 * Has "pcap_breakloop()" been called?
385 * If so, return immediately - if we haven't read any
386 * packets, clear the flag and return -2 to indicate
387 * that we were told to break out of the loop, otherwise
388 * leave the flag set, so that the *next* call will break
389 * out of the loop without having read any packets, and
390 * return the number of packets we've processed so far.
391 */
392 if (p->break_loop) {
393 if (n == 0) {
394 p->break_loop = 0;
395 return (-2);
396 } else
397 return (n);
398 }
399
400 status = p->next_packet_op(p, &h, &data);
401 if (status) {
402 if (status == 1)
403 return (0);
404 return (status);
405 }
406
407 if ((fcode = p->fcode.bf_insns) == NULL ||
408 bpf_filter(fcode, data, h.len, h.caplen)) {
409 (*callback)(user, &h, data);
410 if (++n >= cnt && cnt > 0)
411 break;
412 }
413 }
414 /*XXX this breaks semantics tcpslice expects */
415 return (n);
416 }
417