/*

 * Copyright (c) 1993, 1994, 1995, 1996, 1997

 *  The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that: (1) source code distributions

 * retain the above copyright notice and this paragraph in its entirety, (2)

 * distributions including binary code include the above copyright notice and

 * this paragraph in its entirety in the documentation or other materials

 * provided with the distribution, and (3) all advertising materials mentioning

 * features or use of this software display the following acknowledgement:

 * ``This product includes software developed by the University of California,

 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of

 * the University nor the names of its contributors may be used to endorse

 * or promote products derived from this software without specific prior

 * written permission.

 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED

 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

 *

 * savefile.c - supports offline use of tcpdump

 *  Extraction/creation by Jeffrey Mogul, DECWRL

 *  Modified by Steve McCanne, LBL.

 *

 * Used to save the received packet headers, after filtering, to

 * a file, and then read them later.

 * The first record in the file contains saved values for the machine

 * dependent values so we can print the dump file on any architecture.

 */

#include <config.h>

#include <pcap-types.h>

#ifdef _WIN32

#include <io.h>

#include <fcntl.h>

#endif /* _WIN32 */

#include <errno.h>

#include <memory.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <limits.h> /* for INT_MAX */

#include "pcap-int.h"

#ifdef HAVE_OS_PROTO_H

#include "os-proto.h"

#endif

#include "sf-pcap.h"

#include "sf-pcapng.h"

#include "pcap-common.h"

#include "charconv.h"

#ifdef _WIN32

/*

 * This isn't exported on Windows, because it would only work if both

 * WinPcap/Npcap and the code using it were to use the Universal CRT; otherwise,

 * a FILE structure in WinPcap/Npcap and a FILE structure in the code using it

 * could be different if they're using different versions of the C runtime.

 *

 * Instead, pcap/pcap.h defines it as a macro that wraps the hopen version,

 * with the wrapper calling _fileno() and _get_osfhandle() themselves,

 * so that it convert the appropriate CRT version's FILE structure to

 * a HANDLE (which is OS-defined, not CRT-defined, and is part of the Win32

 * and Win64 ABIs).

 */

static pcap_t *pcap_fopen_offline_with_tstamp_precision(FILE *, u_int, char *);

#endif

/*

 * Setting O_BINARY on Windows is a bit tricky.

 */

#if defined(_WIN32)

  #define SET_BINMODE(f)  _setmode(_fileno(f), _O_BINARY)

#endif

static int

sf_getnonblock(pcap_t *p _U_)

{

  /*

   * This is a savefile, not a live capture file, so never say

   * it's in non-blocking mode.

   */

  return (0);

}

static int

sf_setnonblock(pcap_t *p, int nonblock _U_)

{

  /*

   * This is a savefile, not a live capture file, so reject

   * requests to put it in non-blocking mode.  (If it's a

   * pipe, it could be put in non-blocking mode, but that

   * would significantly complicate the code to read packets,

   * as it would have to handle reading partial packets and

   * keeping the state of the read.)

   */

  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

      "Savefiles cannot be put into non-blocking mode");

  return (-1);

}

static int

sf_cant_set_rfmon(pcap_t *p _U_)

{

  /*

   * This is a savefile, not a device on which you can capture,

   * so never say it supports being put into monitor mode.

   */

  return (0);

}

static int

sf_stats(pcap_t *p, struct pcap_stat *ps _U_)

{

  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

      "Statistics aren't available from savefiles");

  return (-1);

}

#ifdef _WIN32

static struct pcap_stat *

sf_stats_ex(pcap_t *p, int *size _U_)

{

  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

      "Statistics aren't available from savefiles");

  return (NULL);

}

static int

sf_setbuff(pcap_t *p, int dim _U_)

{

  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

      "The kernel buffer size cannot be set while reading from a file");

  return (-1);

}

static int

sf_setmode(pcap_t *p, int mode _U_)

{

  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

      "impossible to set mode while reading from a file");

  return (-1);

}

static int

sf_setmintocopy(pcap_t *p, int size _U_)

{

  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

      "The mintocopy parameter cannot be set while reading from a file");

  return (-1);

}

static HANDLE

sf_getevent(pcap_t *pcap)

{

  (void)snprintf(pcap->errbuf, sizeof(pcap->errbuf),

      "The read event cannot be retrieved while reading from a file");

  return (INVALID_HANDLE_VALUE);

}

static int

sf_oid_get_request(pcap_t *p, bpf_u_int32 oid _U_, void *data _U_,

    size_t *lenp _U_)

{

  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

      "An OID get request cannot be performed on a file");

  return (PCAP_ERROR);

}

static int

sf_oid_set_request(pcap_t *p, bpf_u_int32 oid _U_, const void *data _U_,

    size_t *lenp _U_)

{

  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

      "An OID set request cannot be performed on a file");

  return (PCAP_ERROR);

}

static u_int

sf_sendqueue_transmit(pcap_t *p, pcap_send_queue *queue _U_, int sync _U_)

{

  pcapint_strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",

      PCAP_ERRBUF_SIZE);

  return (0);

}

static int

sf_setuserbuffer(pcap_t *p, int size _U_)

{

  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

      "The user buffer cannot be set when reading from a file");

  return (-1);

}

static int

sf_live_dump(pcap_t *p, char *filename _U_, int maxsize _U_, int maxpacks _U_)

{

  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

      "Live packet dumping cannot be performed when reading from a file");

  return (-1);

}

static int

sf_live_dump_ended(pcap_t *p, int sync _U_)

{

  snprintf(p->errbuf, PCAP_ERRBUF_SIZE,

      "Live packet dumping cannot be performed on a pcap_open_dead pcap_t");

  return (-1);

}

static PAirpcapHandle

sf_get_airpcap_handle(pcap_t *pcap _U_)

{

  return (NULL);

}

#endif

static int

sf_inject(pcap_t *p, const void *buf _U_, int size _U_)

{

  pcapint_strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",

      PCAP_ERRBUF_SIZE);

  return (-1);

}

/*

 * Set direction flag: Which packets do we accept on a forwarding

 * single device? IN, OUT or both?

 */

static int

sf_setdirection(pcap_t *p, pcap_direction_t d _U_)

{

  snprintf(p->errbuf, sizeof(p->errbuf),

      "Setting direction is not supported on savefiles");

  return (-1);

}

void

pcapint_sf_cleanup(pcap_t *p)

{

  if (p->rfile != stdin)

    (void)fclose(p->rfile);

  if (p->buffer != NULL)

    free(p->buffer);

  pcap_freecode(&p->fcode);

}

#ifdef _WIN32

/*

 * Wrapper for fopen() and _wfopen().

 *

 * If we're in UTF-8 mode, map the pathname from UTF-8 to UTF-16LE and

 * call _wfopen().

 *

 * If we're not, just use fopen(); that'll treat it as being in the

 * local code page.

 */

FILE *

pcapint_charset_fopen(const char *path, const char *mode)

{

  wchar_t *utf16_path;

#define MAX_MODE_LEN  16

  wchar_t utf16_mode[MAX_MODE_LEN+1];

  int i;

  char c;

  FILE *fp;

  int save_errno;

  if (pcapint_utf_8_mode) {

    /*

     * Map from UTF-8 to UTF-16LE.

     * Fail if there are invalid characters in the input

     * string, rather than converting them to REPLACEMENT

     * CHARACTER; the latter is appropriate for strings

     * to be displayed to the user, but for file names

     * you just want the attempt to open the file to fail.

     */

    utf16_path = cp_to_utf_16le(CP_UTF8, path,

        MB_ERR_INVALID_CHARS);

    if (utf16_path == NULL) {

      /*

       * Error.  Assume errno has been set.

       *

       * XXX - what about Windows errors?

       */

      return (NULL);

    }

    /*

     * Now convert the mode to UTF-16LE as well.

     * We assume the mode is ASCII, and that

     * it's short, so that's easy.

     */

    for (i = 0; (c = *mode) != '\0'; i++, mode++) {

      if (c > 0x7F) {

        /* Not an ASCII character; fail with EINVAL. */

        free(utf16_path);

        errno = EINVAL;

        return (NULL);

      }

      if (i >= MAX_MODE_LEN) {

        /* The mode string is longer than we allow. */

        free(utf16_path);

        errno = EINVAL;

        return (NULL);

      }

      utf16_mode[i] = c;

    }

    utf16_mode[i] = '\0';

    /*

     * OK, we have UTF-16LE strings; hand them to

     * _wfopen().

     */

    fp = _wfopen(utf16_path, utf16_mode);

    /*

     * Make sure freeing the UTF-16LE string doesn't

     * overwrite the error code we got from _wfopen().

     */

    save_errno = errno;

    free(utf16_path);

    errno = save_errno;

    return (fp);

  } else {

    /*

     * This takes strings in the local code page as an

     * argument.

     */

    return (fopen(path, mode));

  }

}

#endif

pcap_t *

pcap_open_offline_with_tstamp_precision(const char *fname, u_int precision,

          char *errbuf)

{

  FILE *fp;

  pcap_t *p;

  if (fname == NULL) {

    snprintf(errbuf, PCAP_ERRBUF_SIZE,

        "A null pointer was supplied as the file name");

    return (NULL);

  }

  if (fname[0] == '-' && fname[1] == '\0')

  {

    fp = stdin;

    if (fp == NULL) {

      snprintf(errbuf, PCAP_ERRBUF_SIZE,

          "The standard input is not open");

      return (NULL);

    }

#if defined(_WIN32)

    /*

     * We're reading from the standard input, so put it in binary

     * mode, as savefiles are binary files.

     */

    SET_BINMODE(fp);

#endif

  }

  else {

    /*

     * Use pcapint_charset_fopen(); on Windows, it tests whether we're

     * in "local code page" or "UTF-8" mode, and treats the

     * pathname appropriately, and on other platforms, it just

     * wraps fopen().

     *

     * "b" is supported as of C90, so *all* UN*Xes should

     * support it, even though it does nothing.

     */

    fp = pcapint_charset_fopen(fname, "rb");

    if (fp == NULL) {

      pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,

          errno, "%s", fname);

      return (NULL);

    }

  }

  p = pcap_fopen_offline_with_tstamp_precision(fp, precision, errbuf);

  if (p == NULL) {

    if (fp != stdin)

      fclose(fp);

  }

  return (p);

}

pcap_t *

pcap_open_offline(const char *fname, char *errbuf)

{

  return (pcap_open_offline_with_tstamp_precision(fname,

      PCAP_TSTAMP_PRECISION_MICRO, errbuf));

}

#ifdef _WIN32

pcap_t* pcap_hopen_offline_with_tstamp_precision(intptr_t osfd, u_int precision,

    char *errbuf)

{

  int fd;

  FILE *file;

  fd = _open_osfhandle(osfd, _O_RDONLY);

  if ( fd < 0 )

  {

    pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,

        errno, "_open_osfhandle");

    return NULL;

  }

  file = _fdopen(fd, "rb");

  if ( file == NULL )

  {

    pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,

        errno, "_fdopen");

    _close(fd);

    return NULL;

  }

  return pcap_fopen_offline_with_tstamp_precision(file, precision,

      errbuf);

}

pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf)

{

  return pcap_hopen_offline_with_tstamp_precision(osfd,

      PCAP_TSTAMP_PRECISION_MICRO, errbuf);

}

#endif

/*

 * Given a link-layer header type and snapshot length, return a

 * snapshot length to use when reading the file; it's guaranteed

 * to be > 0 and <= INT_MAX.

 *

 * XXX - the only reason why we limit it to <= INT_MAX is so that

 * it fits in p->snapshot, and the only reason that p->snapshot is

 * signed is that pcap_snapshot() returns an int, not an unsigned int.

 */

bpf_u_int32

pcapint_adjust_snapshot(bpf_u_int32 linktype, bpf_u_int32 snaplen)

{

  if (snaplen == 0 || snaplen > INT_MAX) {

    /*

     * Bogus snapshot length; use the maximum for this

     * link-layer type as a fallback.

     *

     * XXX - we don't clamp snapshot lengths that are

     * <= INT_MAX but > max_snaplen_for_dlt(linktype),

     * so a capture file could cause us to allocate

     * a Really Big Buffer.

     */

    snaplen = max_snaplen_for_dlt(linktype);

  }

  return snaplen;

}

static pcap_t *(*check_headers[])(const uint8_t *, FILE *, u_int, char *, int *) = {

  pcap_check_header,

  pcap_ng_check_header

};

#define N_FILE_TYPES  (sizeof check_headers / sizeof check_headers[0])

#ifdef _WIN32

static

#endif

pcap_t *

pcap_fopen_offline_with_tstamp_precision(FILE *fp, u_int precision,

    char *errbuf)

{

  register pcap_t *p;

  uint8_t magic[4];

  size_t amt_read;

  u_int i;

  int err;

  /*

   * Fail if we were passed a NULL fp.

   *

   * That shouldn't happen if we're opening with a path name, but

   * it could happen if buggy code is opening with a FILE * and

   * didn't bother to make sure the FILE * isn't null.

   */

  if (fp == NULL) {

    snprintf(errbuf, PCAP_ERRBUF_SIZE,

        "Null FILE * pointer provided to savefile open routine");

    return (NULL);

  }

  /*

   * Read the first 4 bytes of the file; the network analyzer dump

   * file formats we support (pcap and pcapng), and several other

   * formats we might support in the future (such as snoop, DOS and

   * Windows Sniffer, and Microsoft Network Monitor) all have magic

   * numbers that are unique in their first 4 bytes.

   */

  amt_read = fread(&magic, 1, sizeof(magic), fp);

  if (amt_read != sizeof(magic)) {

    if (ferror(fp)) {

      pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,

          errno, "error reading dump file");

    } else {

      snprintf(errbuf, PCAP_ERRBUF_SIZE,

          "truncated dump file; tried to read %zu file header bytes, only got %zu",

          sizeof(magic), amt_read);

    }

    return (NULL);

  }

  /*

   * Try all file types.

   */

  for (i = 0; i < N_FILE_TYPES; i++) {

    p = (*check_headers[i])(magic, fp, precision, errbuf, &err);

    if (p != NULL) {

      /* Yup, that's it. */

      goto found;

    }

    if (err) {

      /*

       * Error trying to read the header.

       */

      return (NULL);

    }

  }

  /*

   * Well, who knows what this mess is....

   */

  snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format");

  return (NULL);

found:

  p->rfile = fp;

  /* Padding only needed for live capture fcode */

  p->fddipad = 0;

#if !defined(_WIN32)

  /*

   * You can do "select()" and "poll()" on plain files on most

   * platforms, and should be able to do so on pipes.

   *

   * You can't do "select()" on anything other than sockets in

   * Windows, so, on Win32 systems, we don't have "selectable_fd".

   */

  p->selectable_fd = fileno(fp);

#endif

  p->can_set_rfmon_op = sf_cant_set_rfmon;

  p->read_op = pcapint_offline_read;

  p->inject_op = sf_inject;

  p->setfilter_op = pcapint_install_bpf_program;

  p->setdirection_op = sf_setdirection;

  p->set_datalink_op = NULL;  /* we don't support munging link-layer headers */

  p->getnonblock_op = sf_getnonblock;

  p->setnonblock_op = sf_setnonblock;

  p->stats_op = sf_stats;

#ifdef _WIN32

  p->stats_ex_op = sf_stats_ex;

  p->setbuff_op = sf_setbuff;

  p->setmode_op = sf_setmode;

  p->setmintocopy_op = sf_setmintocopy;

  p->getevent_op = sf_getevent;

  p->oid_get_request_op = sf_oid_get_request;

  p->oid_set_request_op = sf_oid_set_request;

  p->sendqueue_transmit_op = sf_sendqueue_transmit;

  p->setuserbuffer_op = sf_setuserbuffer;

  p->live_dump_op = sf_live_dump;

  p->live_dump_ended_op = sf_live_dump_ended;

  p->get_airpcap_handle_op = sf_get_airpcap_handle;

#endif

  /*

   * For offline captures, the standard one-shot callback can

   * be used for pcap_next()/pcap_next_ex().

   */

  p->oneshot_callback = pcapint_oneshot;

  /*

   * Default breakloop operation.

   */

  p->breakloop_op = pcapint_breakloop_common;

  /*

   * Savefiles never require special BPF code generation.

   */

  p->bpf_codegen_flags = 0;

  p->activated = 1;

  return (p);

}

/*

 * This isn't needed on Windows; we #define pcap_fopen_offline() as

 * a wrapper around pcap_hopen_offline(), and we don't call it from

 * inside this file, so it's unused.

 */

#ifndef _WIN32

pcap_t *

pcap_fopen_offline(FILE *fp, char *errbuf)

{

  return (pcap_fopen_offline_with_tstamp_precision(fp,

      PCAP_TSTAMP_PRECISION_MICRO, errbuf));

}

#endif

/*

 * Read packets from a capture file, and call the callback for each

 * packet.

 * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.

 */

int

pcapint_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)

{

  struct bpf_insn *fcode;

  int n = 0;

  u_char *data;

  /*

   * This can conceivably process more than INT_MAX packets,

   * which would overflow the packet count, causing it either

   * to look like a negative number, and thus cause us to

   * return a value that looks like an error, or overflow

   * back into positive territory, and thus cause us to

   * return a too-low count.

   *

   * Therefore, if the packet count is unlimited, we clip

   * it at INT_MAX; this routine is not expected to

   * process packets indefinitely, so that's not an issue.

   */

  if (PACKET_COUNT_IS_UNLIMITED(cnt))

    cnt = INT_MAX;

  for (;;) {

    struct pcap_pkthdr h;

    int status;

    /*

     * Has "pcap_breakloop()" been called?

     * If so, return immediately - if we haven't read any

     * packets, clear the flag and return -2 to indicate

     * that we were told to break out of the loop, otherwise

     * leave the flag set, so that the *next* call will break

     * out of the loop without having read any packets, and

     * return the number of packets we've processed so far.

     */

    if (p->break_loop) {

      if (n == 0) {

        p->break_loop = 0;

        return (-2);

      } else

        return (n);

    }

    status = p->next_packet_op(p, &h, &data);

    if (status < 0) {

      /*

       * Error.  Pass it back to the caller.

       */

      return (status);

    }

    if (status == 0) {

      /*

       * EOF.  Nothing more to process;

       */

      break;

    }

    /*

     * OK, we've read a packet; run it through the filter

     * and, if it passes, process it.

     */

    if ((fcode = p->fcode.bf_insns) == NULL ||

        pcapint_filter(fcode, data, h.len, h.caplen)) {

      (*callback)(user, &h, data);

      n++;  /* count the packet */

      if (n >= cnt)

        break;

    }

  }

  /*XXX this breaks semantics tcpslice expects */

  return (n);

}