savefile.c revision 335640
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#include <pcap-types.h> 36#ifdef _WIN32 37#include <io.h> 38#include <fcntl.h> 39#endif /* _WIN32 */ 40 41#include <errno.h> 42#include <memory.h> 43#include <stdio.h> 44#include <stdlib.h> 45#include <string.h> 46 47#include "pcap-int.h" 48 49#ifdef HAVE_OS_PROTO_H 50#include "os-proto.h" 51#endif 52 53#include "sf-pcap.h" 54#include "sf-pcapng.h" 55 56#ifdef _WIN32 57/* 58 * These aren't exported on Windows, because they would only work if both 59 * WinPcap and the code using it were to use the Universal CRT; otherwise, 60 * a FILE structure in WinPcap and a FILE structure in the code using it 61 * could be different if they're using different versions of the C runtime. 62 * 63 * Instead, pcap/pcap.h defines them as macros that wrap the hopen versions, 64 * with the wrappers calling _fileno() and _get_osfhandle() themselves, 65 * so that they convert the appropriate CRT version's FILE structure to 66 * a HANDLE (which is OS-defined, not CRT-defined, and is part of the Win32 67 * and Win64 ABIs). 68 */ 69static pcap_t *pcap_fopen_offline_with_tstamp_precision(FILE *, u_int, char *); 70static pcap_t *pcap_fopen_offline(FILE *, char *); 71#endif 72 73/* 74 * Setting O_BINARY on DOS/Windows is a bit tricky 75 */ 76#if defined(_WIN32) 77 #define SET_BINMODE(f) _setmode(_fileno(f), _O_BINARY) 78#elif defined(MSDOS) 79 #if defined(__HIGHC__) 80 #define SET_BINMODE(f) setmode(f, O_BINARY) 81 #else 82 #define SET_BINMODE(f) setmode(fileno(f), O_BINARY) 83 #endif 84#endif 85 86static int 87sf_getnonblock(pcap_t *p _U_) 88{ 89 /* 90 * This is a savefile, not a live capture file, so never say 91 * it's in non-blocking mode. 92 */ 93 return (0); 94} 95 96static int 97sf_setnonblock(pcap_t *p, int nonblock _U_) 98{ 99 /* 100 * This is a savefile, not a live capture file, so reject 101 * requests to put it in non-blocking mode. (If it's a 102 * pipe, it could be put in non-blocking mode, but that 103 * would significantly complicate the code to read packets, 104 * as it would have to handle reading partial packets and 105 * keeping the state of the read.) 106 */ 107 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 108 "Savefiles cannot be put into non-blocking mode"); 109 return (-1); 110} 111 112static int 113sf_stats(pcap_t *p, struct pcap_stat *ps _U_) 114{ 115 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 116 "Statistics aren't available from savefiles"); 117 return (-1); 118} 119 120#ifdef _WIN32 121static struct pcap_stat * 122sf_stats_ex(pcap_t *p, int *size) 123{ 124 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 125 "Statistics aren't available from savefiles"); 126 return (NULL); 127} 128 129static int 130sf_setbuff(pcap_t *p, int dim) 131{ 132 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 133 "The kernel buffer size cannot be set while reading from a file"); 134 return (-1); 135} 136 137static int 138sf_setmode(pcap_t *p, int mode) 139{ 140 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 141 "impossible to set mode while reading from a file"); 142 return (-1); 143} 144 145static int 146sf_setmintocopy(pcap_t *p, int size) 147{ 148 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 149 "The mintocopy parameter cannot be set while reading from a file"); 150 return (-1); 151} 152 153static HANDLE 154sf_getevent(pcap_t *pcap) 155{ 156 (void)pcap_snprintf(pcap->errbuf, sizeof(pcap->errbuf), 157 "The read event cannot be retrieved while reading from a file"); 158 return (INVALID_HANDLE_VALUE); 159} 160 161static int 162sf_oid_get_request(pcap_t *p, bpf_u_int32 oid _U_, void *data _U_, 163 size_t *lenp _U_) 164{ 165 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 166 "An OID get request cannot be performed on a file"); 167 return (PCAP_ERROR); 168} 169 170static int 171sf_oid_set_request(pcap_t *p, bpf_u_int32 oid _U_, const void *data _U_, 172 size_t *lenp _U_) 173{ 174 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 175 "An OID set request cannot be performed on a file"); 176 return (PCAP_ERROR); 177} 178 179static u_int 180sf_sendqueue_transmit(pcap_t *p, pcap_send_queue *queue, int sync) 181{ 182 strlcpy(p->errbuf, "Sending packets isn't supported on savefiles", 183 PCAP_ERRBUF_SIZE); 184 return (0); 185} 186 187static int 188sf_setuserbuffer(pcap_t *p, int size) 189{ 190 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 191 "The user buffer cannot be set when reading from a file"); 192 return (-1); 193} 194 195static int 196sf_live_dump(pcap_t *p, char *filename, int maxsize, int maxpacks) 197{ 198 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 199 "Live packet dumping cannot be performed when reading from a file"); 200 return (-1); 201} 202 203static int 204sf_live_dump_ended(pcap_t *p, int sync) 205{ 206 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 207 "Live packet dumping cannot be performed on a pcap_open_dead pcap_t"); 208 return (-1); 209} 210 211static PAirpcapHandle 212sf_get_airpcap_handle(pcap_t *pcap) 213{ 214 return (NULL); 215} 216#endif 217 218static int 219sf_inject(pcap_t *p, const void *buf _U_, size_t size _U_) 220{ 221 strlcpy(p->errbuf, "Sending packets isn't supported on savefiles", 222 PCAP_ERRBUF_SIZE); 223 return (-1); 224} 225 226/* 227 * Set direction flag: Which packets do we accept on a forwarding 228 * single device? IN, OUT or both? 229 */ 230static int 231sf_setdirection(pcap_t *p, pcap_direction_t d _U_) 232{ 233 pcap_snprintf(p->errbuf, sizeof(p->errbuf), 234 "Setting direction is not supported on savefiles"); 235 return (-1); 236} 237 238void 239sf_cleanup(pcap_t *p) 240{ 241 if (p->rfile != stdin) 242 (void)fclose(p->rfile); 243 if (p->buffer != NULL) 244 free(p->buffer); 245 pcap_freecode(&p->fcode); 246} 247 248pcap_t * 249pcap_open_offline_with_tstamp_precision(const char *fname, u_int precision, 250 char *errbuf) 251{ 252 FILE *fp; 253 pcap_t *p; 254 255 if (fname == NULL) { 256 pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, 257 "A null pointer was supplied as the file name"); 258 return (NULL); 259 } 260 if (fname[0] == '-' && fname[1] == '\0') 261 { 262 fp = stdin; 263#if defined(_WIN32) || defined(MSDOS) 264 /* 265 * We're reading from the standard input, so put it in binary 266 * mode, as savefiles are binary files. 267 */ 268 SET_BINMODE(fp); 269#endif 270 } 271 else { 272 /* 273 * "b" is supported as of C90, so *all* UN*Xes should 274 * support it, even though it does nothing. It's 275 * required on Windows, as the file is a binary file 276 * and must be read in binary mode. 277 */ 278 fp = fopen(fname, "rb"); 279 if (fp == NULL) { 280 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 281 errno, "%s", fname); 282 return (NULL); 283 } 284 } 285 p = pcap_fopen_offline_with_tstamp_precision(fp, precision, errbuf); 286 if (p == NULL) { 287 if (fp != stdin) 288 fclose(fp); 289 } 290 return (p); 291} 292 293pcap_t * 294pcap_open_offline(const char *fname, char *errbuf) 295{ 296 return (pcap_open_offline_with_tstamp_precision(fname, 297 PCAP_TSTAMP_PRECISION_MICRO, errbuf)); 298} 299 300#ifdef _WIN32 301pcap_t* pcap_hopen_offline_with_tstamp_precision(intptr_t osfd, u_int precision, 302 char *errbuf) 303{ 304 int fd; 305 FILE *file; 306 307 fd = _open_osfhandle(osfd, _O_RDONLY); 308 if ( fd < 0 ) 309 { 310 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 311 errno, "_open_osfhandle"); 312 return NULL; 313 } 314 315 file = _fdopen(fd, "rb"); 316 if ( file == NULL ) 317 { 318 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 319 errno, "_fdopen"); 320 return NULL; 321 } 322 323 return pcap_fopen_offline_with_tstamp_precision(file, precision, 324 errbuf); 325} 326 327pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf) 328{ 329 return pcap_hopen_offline_with_tstamp_precision(osfd, 330 PCAP_TSTAMP_PRECISION_MICRO, errbuf); 331} 332#endif 333 334static pcap_t *(*check_headers[])(bpf_u_int32, FILE *, u_int, char *, int *) = { 335 pcap_check_header, 336 pcap_ng_check_header 337}; 338 339#define N_FILE_TYPES (sizeof check_headers / sizeof check_headers[0]) 340 341#ifdef _WIN32 342static 343#endif 344pcap_t * 345pcap_fopen_offline_with_tstamp_precision(FILE *fp, u_int precision, 346 char *errbuf) 347{ 348 register pcap_t *p; 349 bpf_u_int32 magic; 350 size_t amt_read; 351 u_int i; 352 int err; 353 354 /* 355 * Read the first 4 bytes of the file; the network analyzer dump 356 * file formats we support (pcap and pcapng), and several other 357 * formats we might support in the future (such as snoop, DOS and 358 * Windows Sniffer, and Microsoft Network Monitor) all have magic 359 * numbers that are unique in their first 4 bytes. 360 */ 361 amt_read = fread((char *)&magic, 1, sizeof(magic), fp); 362 if (amt_read != sizeof(magic)) { 363 if (ferror(fp)) { 364 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, 365 errno, "error reading dump file"); 366 } else { 367 pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, 368 "truncated dump file; tried to read %lu file header bytes, only got %lu", 369 (unsigned long)sizeof(magic), 370 (unsigned long)amt_read); 371 } 372 return (NULL); 373 } 374 375 /* 376 * Try all file types. 377 */ 378 for (i = 0; i < N_FILE_TYPES; i++) { 379 p = (*check_headers[i])(magic, fp, precision, errbuf, &err); 380 if (p != NULL) { 381 /* Yup, that's it. */ 382 goto found; 383 } 384 if (err) { 385 /* 386 * Error trying to read the header. 387 */ 388 return (NULL); 389 } 390 } 391 392 /* 393 * Well, who knows what this mess is.... 394 */ 395 pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format"); 396 return (NULL); 397 398found: 399 p->rfile = fp; 400 401 /* Padding only needed for live capture fcode */ 402 p->fddipad = 0; 403 404#if !defined(_WIN32) && !defined(MSDOS) 405 /* 406 * You can do "select()" and "poll()" on plain files on most 407 * platforms, and should be able to do so on pipes. 408 * 409 * You can't do "select()" on anything other than sockets in 410 * Windows, so, on Win32 systems, we don't have "selectable_fd". 411 */ 412 p->selectable_fd = fileno(fp); 413#endif 414 415 p->read_op = pcap_offline_read; 416 p->inject_op = sf_inject; 417 p->setfilter_op = install_bpf_program; 418 p->setdirection_op = sf_setdirection; 419 p->set_datalink_op = NULL; /* we don't support munging link-layer headers */ 420 p->getnonblock_op = sf_getnonblock; 421 p->setnonblock_op = sf_setnonblock; 422 p->stats_op = sf_stats; 423#ifdef _WIN32 424 p->stats_ex_op = sf_stats_ex; 425 p->setbuff_op = sf_setbuff; 426 p->setmode_op = sf_setmode; 427 p->setmintocopy_op = sf_setmintocopy; 428 p->getevent_op = sf_getevent; 429 p->oid_get_request_op = sf_oid_get_request; 430 p->oid_set_request_op = sf_oid_set_request; 431 p->sendqueue_transmit_op = sf_sendqueue_transmit; 432 p->setuserbuffer_op = sf_setuserbuffer; 433 p->live_dump_op = sf_live_dump; 434 p->live_dump_ended_op = sf_live_dump_ended; 435 p->get_airpcap_handle_op = sf_get_airpcap_handle; 436#endif 437 438 /* 439 * For offline captures, the standard one-shot callback can 440 * be used for pcap_next()/pcap_next_ex(). 441 */ 442 p->oneshot_callback = pcap_oneshot; 443 444 /* 445 * Savefiles never require special BPF code generation. 446 */ 447 p->bpf_codegen_flags = 0; 448 449 p->activated = 1; 450 451 return (p); 452} 453 454#ifdef _WIN32 455static 456#endif 457pcap_t * 458pcap_fopen_offline(FILE *fp, char *errbuf) 459{ 460 return (pcap_fopen_offline_with_tstamp_precision(fp, 461 PCAP_TSTAMP_PRECISION_MICRO, errbuf)); 462} 463 464/* 465 * Read packets from a capture file, and call the callback for each 466 * packet. 467 * If cnt > 0, return after 'cnt' packets, otherwise continue until eof. 468 */ 469int 470pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user) 471{ 472 struct bpf_insn *fcode; 473 int status = 0; 474 int n = 0; 475 u_char *data; 476 477 while (status == 0) { 478 struct pcap_pkthdr h; 479 480 /* 481 * Has "pcap_breakloop()" been called? 482 * If so, return immediately - if we haven't read any 483 * packets, clear the flag and return -2 to indicate 484 * that we were told to break out of the loop, otherwise 485 * leave the flag set, so that the *next* call will break 486 * out of the loop without having read any packets, and 487 * return the number of packets we've processed so far. 488 */ 489 if (p->break_loop) { 490 if (n == 0) { 491 p->break_loop = 0; 492 return (-2); 493 } else 494 return (n); 495 } 496 497 status = p->next_packet_op(p, &h, &data); 498 if (status) { 499 if (status == 1) 500 return (0); 501 return (status); 502 } 503 504 if ((fcode = p->fcode.bf_insns) == NULL || 505 bpf_filter(fcode, data, h.len, h.caplen)) { 506 (*callback)(user, &h, data); 507 if (++n >= cnt && cnt > 0) 508 break; 509 } 510 } 511 /*XXX this breaks semantics tcpslice expects */ 512 return (n); 513} 514