The Tcpdump Group git mirrors - libpcap/blob - savefile.c

   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 #ifdef _WIN32
  66 /*
  67  * These aren't exported on Windows, because they would only work if both
  68  * WinPcap and the code using it were to use the Universal CRT; otherwise,
  69  * a FILE structure in WinPcap and a FILE structure in the code using it
  70  * could be different if they're using different versions of the C runtime.
  71  *
  72  * Instead, pcap/pcap.h defines them as macros that wrap the hopen versions,
  73  * with the wrappers calling _fileno() and _get_osfhandle() themselves,
  74  * so that they convert the appropriate CRT version's FILE structure to
  75  * a HANDLE (which is OS-defined, not CRT-defined, and is part of the Win32
  76  * and Win64 ABIs).
  77  */
  78 static pcap_t *pcap_fopen_offline_with_tstamp_precision(FILE *, u_int, char *);
  79 static pcap_t *pcap_fopen_offline(FILE *, char *);
  80 #endif
  81
  82 /*
  83  * Setting O_BINARY on DOS/Windows is a bit tricky
  84  */
  85 #if defined(_WIN32)
  86   #define SET_BINMODE(f)  _setmode(_fileno(f), _O_BINARY)
  87 #elif defined(MSDOS)
  88   #if defined(__HIGHC__)
  89   #define SET_BINMODE(f)  setmode(f, O_BINARY)
  90   #else
  91   #define SET_BINMODE(f)  setmode(fileno(f), O_BINARY)
  92   #endif
  93 #endif
  94
  95 static int
  96 sf_getnonblock(pcap_t *p, char *errbuf)
  97 {
  98         /*
  99          * This is a savefile, not a live capture file, so never say
 100          * it's in non-blocking mode.
 101          */
 102         return (0);
 103 }
 104
 105 static int
 106 sf_setnonblock(pcap_t *p, int nonblock, char *errbuf)
 107 {
 108         /*
 109          * This is a savefile, not a live capture file, so reject
 110          * requests to put it in non-blocking mode.  (If it's a
 111          * pipe, it could be put in non-blocking mode, but that
 112          * would significantly complicate the code to read packets,
 113          * as it would have to handle reading partial packets and
 114          * keeping the state of the read.)
 115          */
 116         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 117             "Savefiles cannot be put into non-blocking mode");
 118         return (-1);
 119 }
 120
 121 static int
 122 sf_stats(pcap_t *p, struct pcap_stat *ps)
 123 {
 124         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 125             "Statistics aren't available from savefiles");
 126         return (-1);
 127 }
 128
 129 #ifdef _WIN32
 130 static struct pcap_stat *
 131 sf_stats_ex(pcap_t *p, int *size)
 132 {
 133         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 134             "Statistics aren't available from savefiles");
 135         return (NULL);
 136 }
 137
 138 static int
 139 sf_setbuff(pcap_t *p, int dim)
 140 {
 141         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 142             "The kernel buffer size cannot be set while reading from a file");
 143         return (-1);
 144 }
 145
 146 static int
 147 sf_setmode(pcap_t *p, int mode)
 148 {
 149         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 150             "impossible to set mode while reading from a file");
 151         return (-1);
 152 }
 153
 154 static int
 155 sf_setmintocopy(pcap_t *p, int size)
 156 {
 157         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 158             "The mintocopy parameter cannot be set while reading from a file");
 159         return (-1);
 160 }
 161
 162 static HANDLE
 163 sf_getevent(pcap_t *pcap)
 164 {
 165         (void)pcap_snprintf(pcap->errbuf, sizeof(pcap->errbuf),
 166             "The read event cannot be retrieved while reading from a file");
 167         return (INVALID_HANDLE_VALUE);
 168 }
 169
 170 static int
 171 sf_oid_get_request(pcap_t *p, bpf_u_int32 oid _U_, void *data _U_,
 172     size_t *lenp _U_)
 173 {
 174         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 175             "An OID get request cannot be performed on a file");
 176         return (PCAP_ERROR);
 177 }
 178
 179 static int
 180 sf_oid_set_request(pcap_t *p, bpf_u_int32 oid _U_, const void *data _U_,
 181     size_t *lenp _U_)
 182 {
 183         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 184             "An OID set request cannot be performed on a file");
 185         return (PCAP_ERROR);
 186 }
 187
 188 static u_int
 189 sf_sendqueue_transmit(pcap_t *p, pcap_send_queue *queue, int sync)
 190 {
 191         strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
 192             PCAP_ERRBUF_SIZE);
 193         return (0);
 194 }
 195
 196 static int
 197 sf_setuserbuffer(pcap_t *p, int size)
 198 {
 199         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 200             "The user buffer cannot be set when reading from a file");
 201         return (-1);
 202 }
 203
 204 static int
 205 sf_live_dump(pcap_t *p, char *filename, int maxsize, int maxpacks)
 206 {
 207         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 208             "Live packet dumping cannot be performed when reading from a file");
 209         return (-1);
 210 }
 211
 212 static int
 213 sf_live_dump_ended(pcap_t *p, int sync)
 214 {
 215         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 216             "Live packet dumping cannot be performed on a pcap_open_dead pcap_t");
 217         return (-1);
 218 }
 219
 220 static PAirpcapHandle
 221 sf_get_airpcap_handle(pcap_t *pcap)
 222 {
 223         return (NULL);
 224 }
 225 #endif
 226
 227 static int
 228 sf_inject(pcap_t *p, const void *buf _U_, size_t size _U_)
 229 {
 230         strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
 231             PCAP_ERRBUF_SIZE);
 232         return (-1);
 233 }
 234
 235 /*
 236  * Set direction flag: Which packets do we accept on a forwarding
 237  * single device? IN, OUT or both?
 238  */
 239 static int
 240 sf_setdirection(pcap_t *p, pcap_direction_t d)
 241 {
 242         pcap_snprintf(p->errbuf, sizeof(p->errbuf),
 243             "Setting direction is not supported on savefiles");
 244         return (-1);
 245 }
 246
 247 void
 248 sf_cleanup(pcap_t *p)
 249 {
 250         if (p->rfile != stdin)
 251                 (void)fclose(p->rfile);
 252         if (p->buffer != NULL)
 253                 free(p->buffer);
 254         pcap_freecode(&p->fcode);
 255 }
 256
 257 /*
 258 * fopen's safe version on Windows.
 259 */
 260 #ifdef _MSC_VER
 261 FILE *fopen_safe(const char *filename, const char* mode)
 262 {
 263         FILE *fp = NULL;
 264         errno_t errno;
 265         errno = fopen_s(&fp, filename, mode);
 266         if (errno == 0)
 267                 return fp;
 268         else
 269                 return NULL;
 270 }
 271 #endif
 272
 273 pcap_t *
 274 pcap_open_offline_with_tstamp_precision(const char *fname, u_int precision,
 275     char *errbuf)
 276 {
 277         FILE *fp;
 278         pcap_t *p;
 279
 280         if (fname[0] == '-' && fname[1] == '\0')
 281         {
 282                 fp = stdin;
 283 #if defined(_WIN32) || defined(MSDOS)
 284                 /*
 285                  * We're reading from the standard input, so put it in binary
 286                  * mode, as savefiles are binary files.
 287                  */
 288                 SET_BINMODE(fp);
 289 #endif
 290         }
 291         else {
 292 #if !defined(_WIN32) && !defined(MSDOS)
 293                 fp = fopen(fname, "r");
 294 #else
 295                 fp = fopen(fname, "rb");
 296 #endif
 297                 if (fp == NULL) {
 298                         pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname,
 299                             pcap_strerror(errno));
 300                         return (NULL);
 301                 }
 302         }
 303         p = pcap_fopen_offline_with_tstamp_precision(fp, precision, errbuf);
 304         if (p == NULL) {
 305                 if (fp != stdin)
 306                         fclose(fp);
 307         }
 308         return (p);
 309 }
 310
 311 pcap_t *
 312 pcap_open_offline(const char *fname, char *errbuf)
 313 {
 314         return (pcap_open_offline_with_tstamp_precision(fname,
 315             PCAP_TSTAMP_PRECISION_MICRO, errbuf));
 316 }
 317
 318 #ifdef _WIN32
 319 pcap_t* pcap_hopen_offline_with_tstamp_precision(intptr_t osfd, u_int precision,
 320     char *errbuf)
 321 {
 322         int fd;
 323         FILE *file;
 324
 325         fd = _open_osfhandle(osfd, _O_RDONLY);
 326         if ( fd < 0 )
 327         {
 328                 pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno));
 329                 return NULL;
 330         }
 331
 332         file = _fdopen(fd, "rb");
 333         if ( file == NULL )
 334         {
 335                 pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno));
 336                 return NULL;
 337         }
 338
 339         return pcap_fopen_offline_with_tstamp_precision(file, precision,
 340             errbuf);
 341 }
 342
 343 pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf)
 344 {
 345         return pcap_hopen_offline_with_tstamp_precision(osfd,
 346             PCAP_TSTAMP_PRECISION_MICRO, errbuf);
 347 }
 348 #endif
 349
 350 static pcap_t *(*check_headers[])(bpf_u_int32, FILE *, u_int, char *, int *) = {
 351         pcap_check_header,
 352         pcap_ng_check_header
 353 };
 354
 355 #define N_FILE_TYPES    (sizeof check_headers / sizeof check_headers[0])
 356
 357 #ifdef _WIN32
 358 static
 359 #endif
 360 pcap_t *
 361 pcap_fopen_offline_with_tstamp_precision(FILE *fp, u_int precision,
 362     char *errbuf)
 363 {
 364         register pcap_t *p;
 365         bpf_u_int32 magic;
 366         size_t amt_read;
 367         u_int i;
 368         int err;
 369
 370         /*
 371          * Read the first 4 bytes of the file; the network analyzer dump
 372          * file formats we support (pcap and pcap-ng), and several other
 373          * formats we might support in the future (such as snoop, DOS and
 374          * Windows Sniffer, and Microsoft Network Monitor) all have magic
 375          * numbers that are unique in their first 4 bytes.
 376          */
 377         amt_read = fread((char *)&magic, 1, sizeof(magic), fp);
 378         if (amt_read != sizeof(magic)) {
 379                 if (ferror(fp)) {
 380                         pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
 381                             "error reading dump file: %s",
 382                             pcap_strerror(errno));
 383                 } else {
 384                         pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
 385                             "truncated dump file; tried to read %lu file header bytes, only got %lu",
 386                             (unsigned long)sizeof(magic),
 387                             (unsigned long)amt_read);
 388                 }
 389                 return (NULL);
 390         }
 391
 392         /*
 393          * Try all file types.
 394          */
 395         for (i = 0; i < N_FILE_TYPES; i++) {
 396                 p = (*check_headers[i])(magic, fp, precision, errbuf, &err);
 397                 if (p != NULL) {
 398                         /* Yup, that's it. */
 399                         goto found;
 400                 }
 401                 if (err) {
 402                         /*
 403                          * Error trying to read the header.
 404                          */
 405                         return (NULL);
 406                 }
 407         }
 408
 409         /*
 410          * Well, who knows what this mess is....
 411          */
 412         pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format");
 413         return (NULL);
 414
 415 found:
 416         p->rfile = fp;
 417
 418         /* Padding only needed for live capture fcode */
 419         p->fddipad = 0;
 420
 421 #if !defined(_WIN32) && !defined(MSDOS)
 422         /*
 423          * You can do "select()" and "poll()" on plain files on most
 424          * platforms, and should be able to do so on pipes.
 425          *
 426          * You can't do "select()" on anything other than sockets in
 427          * Windows, so, on Win32 systems, we don't have "selectable_fd".
 428          */
 429         p->selectable_fd = fileno(fp);
 430 #endif
 431
 432         p->read_op = pcap_offline_read;
 433         p->inject_op = sf_inject;
 434         p->setfilter_op = install_bpf_program;
 435         p->setdirection_op = sf_setdirection;
 436         p->set_datalink_op = NULL;      /* we don't support munging link-layer headers */
 437         p->getnonblock_op = sf_getnonblock;
 438         p->setnonblock_op = sf_setnonblock;
 439         p->stats_op = sf_stats;
 440 #ifdef _WIN32
 441         p->stats_ex_op = sf_stats_ex;
 442         p->setbuff_op = sf_setbuff;
 443         p->setmode_op = sf_setmode;
 444         p->setmintocopy_op = sf_setmintocopy;
 445         p->getevent_op = sf_getevent;
 446         p->oid_get_request_op = sf_oid_get_request;
 447         p->oid_set_request_op = sf_oid_set_request;
 448         p->sendqueue_transmit_op = sf_sendqueue_transmit;
 449         p->setuserbuffer_op = sf_setuserbuffer;
 450         p->live_dump_op = sf_live_dump;
 451         p->live_dump_ended_op = sf_live_dump_ended;
 452         p->get_airpcap_handle_op = sf_get_airpcap_handle;
 453 #endif
 454
 455         /*
 456          * For offline captures, the standard one-shot callback can
 457          * be used for pcap_next()/pcap_next_ex().
 458          */
 459         p->oneshot_callback = pcap_oneshot;
 460
 461         /*
 462          * Savefiles never require special BPF code generation.
 463          */
 464         p->bpf_codegen_flags = 0;
 465
 466         p->activated = 1;
 467
 468         return (p);
 469 }
 470
 471 #ifdef _WIN32
 472 static
 473 #endif
 474 pcap_t *
 475 pcap_fopen_offline(FILE *fp, char *errbuf)
 476 {
 477         return (pcap_fopen_offline_with_tstamp_precision(fp,
 478             PCAP_TSTAMP_PRECISION_MICRO, errbuf));
 479 }
 480
 481 /*
 482  * Read packets from a capture file, and call the callback for each
 483  * packet.
 484  * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
 485  */
 486 int
 487 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 488 {
 489         struct bpf_insn *fcode;
 490         int status = 0;
 491         int n = 0;
 492         u_char *data;
 493
 494         while (status == 0) {
 495                 struct pcap_pkthdr h;
 496
 497                 /*
 498                  * Has "pcap_breakloop()" been called?
 499                  * If so, return immediately - if we haven't read any
 500                  * packets, clear the flag and return -2 to indicate
 501                  * that we were told to break out of the loop, otherwise
 502                  * leave the flag set, so that the *next* call will break
 503                  * out of the loop without having read any packets, and
 504                  * return the number of packets we've processed so far.
 505                  */
 506                 if (p->break_loop) {
 507                         if (n == 0) {
 508                                 p->break_loop = 0;
 509                                 return (-2);
 510                         } else
 511                                 return (n);
 512                 }
 513
 514                 status = p->next_packet_op(p, &h, &data);
 515                 if (status) {
 516                         if (status == 1)
 517                                 return (0);
 518                         return (status);
 519                 }
 520
 521                 if ((fcode = p->fcode.bf_insns) == NULL ||
 522                     bpf_filter(fcode, data, h.len, h.caplen)) {
 523                         (*callback)(user, &h, data);
 524                         if (++n >= cnt && cnt > 0)
 525                                 break;
 526                 }
 527         }
 528         /*XXX this breaks semantics tcpslice expects */
 529         return (n);
 530 }