1 /* $NetBSD: savefile.c,v 1.3 2015/03/31 21:39:42 christos Exp $ */
2
3 /*
4 * Copyright (c) 1993, 1994, 1995, 1996, 1997
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that: (1) source code distributions
9 * retain the above copyright notice and this paragraph in its entirety, (2)
10 * distributions including binary code include the above copyright notice and
11 * this paragraph in its entirety in the documentation or other materials
12 * provided with the distribution, and (3) all advertising materials mentioning
13 * features or use of this software display the following acknowledgement:
14 * ``This product includes software developed by the University of California,
15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16 * the University nor the names of its contributors may be used to endorse
17 * or promote products derived from this software without specific prior
18 * written permission.
19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22 *
23 * savefile.c - supports offline use of tcpdump
24 * Extraction/creation by Jeffrey Mogul, DECWRL
25 * Modified by Steve McCanne, LBL.
26 *
27 * Used to save the received packet headers, after filtering, to
28 * a file, and then read them later.
29 * The first record in the file contains saved values for the machine
30 * dependent values so we can print the dump file on any architecture.
31 */
32
33 #include <sys/cdefs.h>
34 __RCSID("$NetBSD: savefile.c,v 1.3 2015/03/31 21:39:42 christos Exp $");
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
83 static int
sf_getnonblock(pcap_t * p,char * errbuf)84 sf_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
93 static int
sf_setnonblock(pcap_t * p,int nonblock,char * errbuf)94 sf_setnonblock(pcap_t *p, int nonblock, char *errbuf)
95 {
96 /*
97 * This is a savefile, not a live capture file, so reject
98 * requests to put it in non-blocking mode. (If it's a
99 * pipe, it could be put in non-blocking mode, but that
100 * would significantly complicate the code to read packets,
101 * as it would have to handle reading partial packets and
102 * keeping the state of the read.)
103 */
104 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
105 "Savefiles cannot be put into non-blocking mode");
106 return (-1);
107 }
108
109 static int
sf_stats(pcap_t * p,struct pcap_stat * ps)110 sf_stats(pcap_t *p, struct pcap_stat *ps)
111 {
112 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
113 "Statistics aren't available from savefiles");
114 return (-1);
115 }
116
117 #ifdef WIN32
118 static int
sf_setbuff(pcap_t * p,int dim)119 sf_setbuff(pcap_t *p, int dim)
120 {
121 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
122 "The kernel buffer size cannot be set while reading from a file");
123 return (-1);
124 }
125
126 static int
sf_setmode(pcap_t * p,int mode)127 sf_setmode(pcap_t *p, int mode)
128 {
129 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
130 "impossible to set mode while reading from a file");
131 return (-1);
132 }
133
134 static int
sf_setmintocopy(pcap_t * p,int size)135 sf_setmintocopy(pcap_t *p, int size)
136 {
137 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
138 "The mintocopy parameter cannot be set while reading from a file");
139 return (-1);
140 }
141 #endif
142
143 static int
sf_inject(pcap_t * p,const void * buf _U_,size_t size _U_)144 sf_inject(pcap_t *p, const void *buf _U_, size_t size _U_)
145 {
146 strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
147 PCAP_ERRBUF_SIZE);
148 return (-1);
149 }
150
151 /*
152 * Set direction flag: Which packets do we accept on a forwarding
153 * single device? IN, OUT or both?
154 */
155 static int
sf_setdirection(pcap_t * p,pcap_direction_t d)156 sf_setdirection(pcap_t *p, pcap_direction_t d)
157 {
158 snprintf(p->errbuf, sizeof(p->errbuf),
159 "Setting direction is not supported on savefiles");
160 return (-1);
161 }
162
163 void
sf_cleanup(pcap_t * p)164 sf_cleanup(pcap_t *p)
165 {
166 if (p->rfile != stdin)
167 (void)fclose(p->rfile);
168 if (p->buffer != NULL)
169 free(p->buffer);
170 pcap_freecode(&p->fcode);
171 }
172
173 pcap_t *
pcap_open_offline_with_tstamp_precision(const char * fname,u_int precision,char * errbuf)174 pcap_open_offline_with_tstamp_precision(const char *fname, u_int precision,
175 char *errbuf)
176 {
177 FILE *fp;
178 pcap_t *p;
179
180 if (fname[0] == '-' && fname[1] == '\0')
181 {
182 fp = stdin;
183 #if defined(WIN32) || defined(MSDOS)
184 /*
185 * We're reading from the standard input, so put it in binary
186 * mode, as savefiles are binary files.
187 */
188 SET_BINMODE(fp);
189 #endif
190 }
191 else {
192 #if !defined(WIN32) && !defined(MSDOS)
193 fp = fopen(fname, "r");
194 #else
195 fp = fopen(fname, "rb");
196 #endif
197 if (fp == NULL) {
198 snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname,
199 pcap_strerror(errno));
200 return (NULL);
201 }
202 }
203 p = pcap_fopen_offline_with_tstamp_precision(fp, precision, errbuf);
204 if (p == NULL) {
205 if (fp != stdin)
206 fclose(fp);
207 }
208 return (p);
209 }
210
211 pcap_t *
pcap_open_offline(const char * fname,char * errbuf)212 pcap_open_offline(const char *fname, char *errbuf)
213 {
214 return (pcap_open_offline_with_tstamp_precision(fname,
215 PCAP_TSTAMP_PRECISION_MICRO, errbuf));
216 }
217
218 #ifdef WIN32
pcap_hopen_offline_with_tstamp_precision(intptr_t osfd,u_int precision,char * errbuf)219 pcap_t* pcap_hopen_offline_with_tstamp_precision(intptr_t osfd, u_int precision,
220 char *errbuf)
221 {
222 int fd;
223 FILE *file;
224
225 fd = _open_osfhandle(osfd, _O_RDONLY);
226 if ( fd < 0 )
227 {
228 snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno));
229 return NULL;
230 }
231
232 file = _fdopen(fd, "rb");
233 if ( file == NULL )
234 {
235 snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno));
236 return NULL;
237 }
238
239 return pcap_fopen_offline_with_tstamp_precision(file, precision,
240 errbuf);
241 }
242
pcap_hopen_offline(intptr_t osfd,char * errbuf)243 pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf)
244 {
245 return pcap_hopen_offline_with_tstamp_precision(osfd,
246 PCAP_TSTAMP_PRECISION_MICRO, errbuf);
247 }
248 #endif
249
250 static pcap_t *(*check_headers[])(bpf_u_int32, FILE *, u_int, char *, int *) = {
251 pcap_check_header,
252 pcap_ng_check_header
253 };
254
255 #define N_FILE_TYPES (sizeof check_headers / sizeof check_headers[0])
256
257 #ifdef WIN32
258 static
259 #endif
260 pcap_t *
pcap_fopen_offline_with_tstamp_precision(FILE * fp,u_int precision,char * errbuf)261 pcap_fopen_offline_with_tstamp_precision(FILE *fp, u_int precision,
262 char *errbuf)
263 {
264 register pcap_t *p;
265 bpf_u_int32 magic;
266 size_t amt_read;
267 u_int i;
268 int err;
269
270 /*
271 * Read the first 4 bytes of the file; the network analyzer dump
272 * file formats we support (pcap and pcap-ng), and several other
273 * formats we might support in the future (such as snoop, DOS and
274 * Windows Sniffer, and Microsoft Network Monitor) all have magic
275 * numbers that are unique in their first 4 bytes.
276 */
277 amt_read = fread((char *)&magic, 1, sizeof(magic), fp);
278 if (amt_read != sizeof(magic)) {
279 if (ferror(fp)) {
280 snprintf(errbuf, PCAP_ERRBUF_SIZE,
281 "error reading dump file: %s",
282 pcap_strerror(errno));
283 } else {
284 snprintf(errbuf, PCAP_ERRBUF_SIZE,
285 "truncated dump file; tried to read %lu file header bytes, only got %lu",
286 (unsigned long)sizeof(magic),
287 (unsigned long)amt_read);
288 }
289 return (NULL);
290 }
291
292 /*
293 * Try all file types.
294 */
295 for (i = 0; i < N_FILE_TYPES; i++) {
296 p = (*check_headers[i])(magic, fp, precision, errbuf, &err);
297 if (p != NULL) {
298 /* Yup, that's it. */
299 goto found;
300 }
301 if (err) {
302 /*
303 * Error trying to read the header.
304 */
305 return (NULL);
306 }
307 }
308
309 /*
310 * Well, who knows what this mess is....
311 */
312 snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format");
313 return (NULL);
314
315 found:
316 p->rfile = fp;
317
318 /* Padding only needed for live capture fcode */
319 p->fddipad = 0;
320
321 #if !defined(WIN32) && !defined(MSDOS)
322 /*
323 * You can do "select()" and "poll()" on plain files on most
324 * platforms, and should be able to do so on pipes.
325 *
326 * You can't do "select()" on anything other than sockets in
327 * Windows, so, on Win32 systems, we don't have "selectable_fd".
328 */
329 p->selectable_fd = fileno(fp);
330 #endif
331
332 p->read_op = pcap_offline_read;
333 p->inject_op = sf_inject;
334 p->setfilter_op = install_bpf_program;
335 p->setdirection_op = sf_setdirection;
336 p->set_datalink_op = NULL; /* we don't support munging link-layer headers */
337 p->getnonblock_op = sf_getnonblock;
338 p->setnonblock_op = sf_setnonblock;
339 p->stats_op = sf_stats;
340 #ifdef WIN32
341 p->setbuff_op = sf_setbuff;
342 p->setmode_op = sf_setmode;
343 p->setmintocopy_op = sf_setmintocopy;
344 #endif
345
346 /*
347 * For offline captures, the standard one-shot callback can
348 * be used for pcap_next()/pcap_next_ex().
349 */
350 p->oneshot_callback = pcap_oneshot;
351
352 /*
353 * Savefiles never require special BPF code generation.
354 */
355 p->bpf_codegen_flags = 0;
356
357 p->activated = 1;
358
359 return (p);
360 }
361
362 #ifdef WIN32
363 static
364 #endif
365 pcap_t *
pcap_fopen_offline(FILE * fp,char * errbuf)366 pcap_fopen_offline(FILE *fp, char *errbuf)
367 {
368 return (pcap_fopen_offline_with_tstamp_precision(fp,
369 PCAP_TSTAMP_PRECISION_MICRO, errbuf));
370 }
371
372 /*
373 * Read packets from a capture file, and call the callback for each
374 * packet.
375 * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
376 */
377 int
pcap_offline_read(pcap_t * p,int cnt,pcap_handler callback,u_char * user)378 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
379 {
380 struct bpf_insn *fcode;
381 int status = 0;
382 int n = 0;
383 u_char *data;
384
385 while (status == 0) {
386 struct pcap_pkthdr h;
387
388 /*
389 * Has "pcap_breakloop()" been called?
390 * If so, return immediately - if we haven't read any
391 * packets, clear the flag and return -2 to indicate
392 * that we were told to break out of the loop, otherwise
393 * leave the flag set, so that the *next* call will break
394 * out of the loop without having read any packets, and
395 * return the number of packets we've processed so far.
396 */
397 if (p->break_loop) {
398 if (n == 0) {
399 p->break_loop = 0;
400 return (-2);
401 } else
402 return (n);
403 }
404
405 status = p->next_packet_op(p, &h, &data);
406 if (status) {
407 if (status == 1)
408 return (0);
409 return (status);
410 }
411
412 if ((fcode = p->fcode.bf_insns) == NULL ||
413 bpf_filter(fcode, data, h.len, h.caplen)) {
414 (*callback)(user, &h, data);
415 if (++n >= cnt && cnt > 0)
416 break;
417 }
418 }
419 /*XXX this breaks semantics tcpslice expects */
420 return (n);
421 }
422