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 #ifndef lint
  32 static const char rcsid[] _U_ =
  33     "@(#) $Header: /tcpdump/master/libpcap/savefile.c,v 1.183 2008-12-23 20:13:29 guy Exp $ (LBL)";
  34 #endif
  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
  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
  94 sf_setnonblock(pcap_t *p, int nonblock, char *errbuf)
  95 {
  96         /*
  97          * This is a savefile, not a live capture file, so ignore
  98          * requests to put it in non-blocking mode.
  99          */
 100         return (0);
 101 }
 102
 103 static int
 104 sf_stats(pcap_t *p, struct pcap_stat *ps)
 105 {
 106         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 107             "Statistics aren't available from savefiles");
 108         return (-1);
 109 }
 110
 111 #ifdef WIN32
 112 static int
 113 sf_setbuff(pcap_t *p, int dim)
 114 {
 115         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 116             "The kernel buffer size cannot be set while reading from a file");
 117         return (-1);
 118 }
 119
 120 static int
 121 sf_setmode(pcap_t *p, int mode)
 122 {
 123         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 124             "impossible to set mode while reading from a file");
 125         return (-1);
 126 }
 127
 128 static int
 129 sf_setmintocopy(pcap_t *p, int size)
 130 {
 131         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 132             "The mintocopy parameter cannot be set while reading from a file");
 133         return (-1);
 134 }
 135 #endif
 136
 137 static int
 138 sf_inject(pcap_t *p, const void *buf _U_, size_t size _U_)
 139 {
 140         strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
 141             PCAP_ERRBUF_SIZE);
 142         return (-1);
 143 }
 144
 145 /*
 146  * Set direction flag: Which packets do we accept on a forwarding
 147  * single device? IN, OUT or both?
 148  */
 149 static int
 150 sf_setdirection(pcap_t *p, pcap_direction_t d)
 151 {
 152         snprintf(p->errbuf, sizeof(p->errbuf),
 153             "Setting direction is not supported on savefiles");
 154         return (-1);
 155 }
 156
 157 static void
 158 sf_cleanup(pcap_t *p)
 159 {
 160         if (p->sf.rfile != stdin)
 161                 (void)fclose(p->sf.rfile);
 162         if (p->buffer != NULL)
 163                 free(p->buffer);
 164 }
 165
 166 pcap_t *
 167 pcap_open_offline(const char *fname, char *errbuf)
 168 {
 169         FILE *fp;
 170         pcap_t *p;
 171
 172         if (fname[0] == '-' && fname[1] == '\0')
 173         {
 174                 fp = stdin;
 175 #if defined(WIN32) || defined(MSDOS)
 176                 /*
 177                  * We're reading from the standard input, so put it in binary
 178                  * mode, as savefiles are binary files.
 179                  */
 180                 SET_BINMODE(fp);
 181 #endif
 182         }
 183         else {
 184 #if !defined(WIN32) && !defined(MSDOS)
 185                 fp = fopen(fname, "r");
 186 #else
 187                 fp = fopen(fname, "rb");
 188 #endif
 189                 if (fp == NULL) {
 190                         snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname,
 191                             pcap_strerror(errno));
 192                         return (NULL);
 193                 }
 194         }
 195         p = pcap_fopen_offline(fp, errbuf);
 196         if (p == NULL) {
 197                 if (fp != stdin)
 198                         fclose(fp);
 199         }
 200         return (p);
 201 }
 202
 203 #ifdef WIN32
 204 pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf)
 205 {
 206         int fd;
 207         FILE *file;
 208
 209         fd = _open_osfhandle(osfd, _O_RDONLY);
 210         if ( fd < 0 )
 211         {
 212                 snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno));
 213                 return NULL;
 214         }
 215
 216         file = _fdopen(fd, "rb");
 217         if ( file == NULL )
 218         {
 219                 snprintf(errbuf, PCAP_ERRBUF_SIZE, pcap_strerror(errno));
 220                 return NULL;
 221         }
 222
 223         return pcap_fopen_offline(file, errbuf);
 224 }
 225 #endif
 226
 227 static int (*check_headers[])(pcap_t *, bpf_u_int32, FILE *, char *) = {
 228         pcap_check_header,
 229         pcap_ng_check_header
 230 };
 231
 232 #define N_FILE_TYPES    (sizeof check_headers / sizeof check_headers[0])
 233
 234 #ifdef WIN32
 235 static
 236 #endif
 237 pcap_t *
 238 pcap_fopen_offline(FILE *fp, char *errbuf)
 239 {
 240         register pcap_t *p;
 241         bpf_u_int32 magic;
 242         size_t amt_read;
 243         u_int i;
 244
 245         p = pcap_create_common("(savefile)", errbuf);
 246         if (p == NULL)
 247                 return (NULL);
 248
 249         /*
 250          * Read the first 4 bytes of the file; the network analyzer dump
 251          * file formats we support (pcap and pcap-ng), and several other
 252          * formats we might support in the future (such as snoop, DOS and
 253          * Windows Sniffer, and Microsoft Network Monitor) all have magic
 254          * numbers that are unique in their first 4 bytes.
 255          */
 256         amt_read = fread((char *)&magic, 1, sizeof(magic), fp);
 257         if (amt_read != sizeof(magic)) {
 258                 if (ferror(fp)) {
 259                         snprintf(errbuf, PCAP_ERRBUF_SIZE,
 260                             "error reading dump file: %s",
 261                             pcap_strerror(errno));
 262                 } else {
 263                         snprintf(errbuf, PCAP_ERRBUF_SIZE,
 264                             "truncated dump file; tried to read %lu file header bytes, only got %lu",
 265                             (unsigned long)sizeof(magic),
 266                             (unsigned long)amt_read);
 267                 }
 268                 goto bad;
 269         }
 270
 271         /*
 272          * Try all file types.
 273          */
 274         for (i = 0; i < N_FILE_TYPES; i++) {
 275                 switch ((*check_headers[i])(p, magic, fp, errbuf)) {
 276
 277                 case -1:
 278                         /*
 279                          * Error trying to read the header.
 280                          */
 281                         goto bad;
 282
 283                 case 1:
 284                         /*
 285                          * Yup, that's it.
 286                          */
 287                         goto found;
 288                 }
 289         }
 290
 291         /*
 292          * Well, who knows what this mess is....
 293          */
 294         snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format");
 295         goto bad;
 296
 297 found:
 298         p->sf.rfile = fp;
 299
 300 #ifdef PCAP_FDDIPAD
 301         /* Padding only needed for live capture fcode */
 302         p->fddipad = 0;
 303 #endif
 304
 305 #if !defined(WIN32) && !defined(MSDOS)
 306         /*
 307          * You can do "select()" and "poll()" on plain files on most
 308          * platforms, and should be able to do so on pipes.
 309          *
 310          * You can't do "select()" on anything other than sockets in
 311          * Windows, so, on Win32 systems, we don't have "selectable_fd".
 312          */
 313         p->selectable_fd = fileno(fp);
 314 #endif
 315
 316         p->read_op = pcap_offline_read;
 317         p->inject_op = sf_inject;
 318         p->setfilter_op = install_bpf_program;
 319         p->setdirection_op = sf_setdirection;
 320         p->set_datalink_op = NULL;      /* we don't support munging link-layer headers */
 321         p->getnonblock_op = sf_getnonblock;
 322         p->setnonblock_op = sf_setnonblock;
 323         p->stats_op = sf_stats;
 324 #ifdef WIN32
 325         p->setbuff_op = sf_setbuff;
 326         p->setmode_op = sf_setmode;
 327         p->setmintocopy_op = sf_setmintocopy;
 328 #endif
 329         p->cleanup_op = sf_cleanup;
 330         p->activated = 1;
 331
 332         return (p);
 333  bad:
 334         free(p);
 335         return (NULL);
 336 }
 337
 338 /*
 339  * Read packets from a capture file, and call the callback for each
 340  * packet.
 341  * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
 342  */
 343 int
 344 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 345 {
 346         struct bpf_insn *fcode;
 347         int status = 0;
 348         int n = 0;
 349         u_char *data;
 350
 351         while (status == 0) {
 352                 struct pcap_pkthdr h;
 353
 354                 /*
 355                  * Has "pcap_breakloop()" been called?
 356                  * If so, return immediately - if we haven't read any
 357                  * packets, clear the flag and return -2 to indicate
 358                  * that we were told to break out of the loop, otherwise
 359                  * leave the flag set, so that the *next* call will break
 360                  * out of the loop without having read any packets, and
 361                  * return the number of packets we've processed so far.
 362                  */
 363                 if (p->break_loop) {
 364                         if (n == 0) {
 365                                 p->break_loop = 0;
 366                                 return (-2);
 367                         } else
 368                                 return (n);
 369                 }
 370
 371                 status = p->sf.next_packet_op(p, &h, &data);
 372                 if (status) {
 373                         if (status == 1)
 374                                 return (0);
 375                         return (status);
 376                 }
 377
 378                 if ((fcode = p->fcode.bf_insns) == NULL ||
 379                     bpf_filter(fcode, p->buffer, h.len, h.caplen)) {
 380                         (*callback)(user, &h, data);
 381                         if (++n >= cnt && cnt > 0)
 382                                 break;
 383                 }
 384         }
 385         /*XXX this breaks semantics tcpslice expects */
 386         return (n);
 387 }