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 int
 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
 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
 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
 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
 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
 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 *
 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 *
 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
 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
 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 *
 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 *
 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
 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 }