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