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