![Guy Harris](/assets/img/avatar_default.png)
wtap_file_read_expected_bytes() from an open routine - open routines are supposed to return -1 on error, 0 if the file doesn't appear to be a file of the specified type, or 1 if the file does appear to be a file of the specified type, but those macros will cause the caller to return FALSE on errors (so that, even if there's an I/O error, it reports "the file isn't a file of the specified type" rather than "we got an error trying to read the file"). When doing reads in an open routine before we've concluded that the file is probably of the right type, return 0, rather than -1, if we get WTAP_ERR_SHORT_READ - if we don't have enough data to check whether a file is of a given type, we should keep trying other types, not give up. For reads done *after* we've concluded the file is probably of the right type, if a read doesn't return the number of bytes we asked for, but returns an error of 0, return WTAP_ERR_SHORT_READ - the file is apparently cut short. For NetMon and NetXRay/Windows Sniffer files, use a #define for the magic number size, and use that for both magic numbers. svn path=/trunk/; revision=46803
453 lines
12 KiB
C
453 lines
12 KiB
C
/* radcom.c
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*
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* $Id$
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*
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* Wiretap Library
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* Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <errno.h>
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#include <string.h>
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#include "wtap-int.h"
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#include "file_wrappers.h"
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#include "buffer.h"
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#include "radcom.h"
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struct frame_date {
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guint16 year;
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guint8 month;
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guint8 day;
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guint32 sec; /* seconds since midnight */
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guint32 usec;
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};
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struct unaligned_frame_date {
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char year[2];
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char month;
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char day;
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char sec[4]; /* seconds since midnight */
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char usec[4];
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};
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/* Found at the beginning of the file. Bytes 2 and 3 (D2:00) seem to be
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* different in some captures */
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static const guint8 radcom_magic[8] = {
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0x42, 0xD2, 0x00, 0x34, 0x12, 0x66, 0x22, 0x88
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};
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static const guint8 encap_magic[4] = {
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0x00, 0x42, 0x43, 0x09
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};
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static const guint8 active_time_magic[11] = {
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0x41, 0x63, 0x74, 0x69, 0x76, 0x65, 0x20, 0x54, 0x69, 0x6d, 0x65
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};
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/* RADCOM record header - followed by frame data (perhaps including FCS).
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"data_length" appears to be the length of packet data following
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the record header. It's 0 in the last record.
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"length" appears to be the amount of captured packet data, and
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"real_length" might be the actual length of the frame on the wire -
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in some captures, it's the same as "length", and, in others,
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it's greater than "length". In the last record, however, those
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may have bogus values (or is that some kind of trailer record?).
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"xxx" appears to be all-zero in all but the last record in one
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capture; if so, perhaps this indicates that the last record is,
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in fact, a trailer of some sort, and some field in the header
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is a record type. */
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struct radcomrec_hdr {
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char xxx[4]; /* unknown */
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char data_length[2]; /* packet length? */
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char xxy[5]; /* unknown */
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struct unaligned_frame_date date; /* date/time stamp of packet */
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char real_length[2]; /* actual length of packet */
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char length[2]; /* captured length of packet */
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char xxz[2]; /* unknown */
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char dce; /* DCE/DTE flag (and other flags?) */
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char xxw[9]; /* unknown */
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};
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static gboolean radcom_read(wtap *wth, int *err, gchar **err_info,
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gint64 *data_offset);
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static gboolean radcom_seek_read(wtap *wth, gint64 seek_off,
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struct wtap_pkthdr *pkhdr, guint8 *pd, int length,
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int *err, gchar **err_info);
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static int radcom_read_rec_header(FILE_T fh, struct radcomrec_hdr *hdr,
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int *err, gchar **err_info);
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static gboolean radcom_read_rec_data(FILE_T fh, guint8 *pd, int length,
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int *err, gchar **err_info);
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int radcom_open(wtap *wth, int *err, gchar **err_info)
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{
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int bytes_read;
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guint8 r_magic[8], t_magic[11], search_encap[7];
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struct frame_date start_date;
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#if 0
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guint32 sec;
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struct tm tm;
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#endif
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/* Read in the string that should be at the start of a RADCOM file */
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(r_magic, 8, wth->fh);
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if (bytes_read != 8) {
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*err = file_error(wth->fh, err_info);
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if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
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return -1;
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return 0;
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}
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/* XXX: bytes 2 and 3 of the "magic" header seem to be different in some
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* captures. We force them to our standard value so that the test
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* succeeds (until we find if they have a special meaning, perhaps a
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* version number ?) */
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r_magic[1] = 0xD2;
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r_magic[2] = 0x00;
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if (memcmp(r_magic, radcom_magic, 8) != 0) {
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return 0;
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}
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/* Look for the "Active Time" string. The "frame_date" structure should
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* be located 32 bytes before the beginning of this string */
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(t_magic, 11, wth->fh);
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if (bytes_read != 11) {
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*err = file_error(wth->fh, err_info);
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if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
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return -1;
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return 0;
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}
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while (memcmp(t_magic, active_time_magic, 11) != 0)
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{
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if (file_seek(wth->fh, -10, SEEK_CUR, err) == -1)
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return -1;
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(t_magic, 11, wth->fh);
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if (bytes_read != 11) {
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*err = file_error(wth->fh, err_info);
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if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
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return -1;
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return 0;
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}
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}
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if (file_seek(wth->fh, -43, SEEK_CUR, err) == -1) return -1;
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/* Get capture start time */
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(&start_date, sizeof(struct frame_date),
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wth->fh);
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if (bytes_read != sizeof(struct frame_date)) {
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*err = file_error(wth->fh, err_info);
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if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
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return -1;
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return 0;
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}
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/* This is a radcom file */
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wth->file_type = WTAP_FILE_RADCOM;
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wth->subtype_read = radcom_read;
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wth->subtype_seek_read = radcom_seek_read;
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wth->snapshot_length = 0; /* not available in header, only in frame */
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wth->tsprecision = WTAP_FILE_TSPREC_USEC;
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#if 0
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tm.tm_year = pletohs(&start_date.year)-1900;
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tm.tm_mon = start_date.month-1;
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tm.tm_mday = start_date.day;
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sec = pletohl(&start_date.sec);
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tm.tm_hour = sec/3600;
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tm.tm_min = (sec%3600)/60;
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tm.tm_sec = sec%60;
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tm.tm_isdst = -1;
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#endif
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if (file_seek(wth->fh, sizeof(struct frame_date), SEEK_CUR, err) == -1)
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return -1;
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(search_encap, 4, wth->fh);
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if (bytes_read != 4) {
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goto read_error;
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}
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while (memcmp(encap_magic, search_encap, 4)) {
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if (file_seek(wth->fh, -3, SEEK_CUR, err) == -1)
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return -1;
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(search_encap, 4, wth->fh);
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if (bytes_read != 4) {
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goto read_error;
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}
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}
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if (file_seek(wth->fh, 12, SEEK_CUR, err) == -1)
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return -1;
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(search_encap, 4, wth->fh);
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if (bytes_read != 4) {
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goto read_error;
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}
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if (memcmp(search_encap, "LAPB", 4) == 0)
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wth->file_encap = WTAP_ENCAP_LAPB;
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else if (memcmp(search_encap, "Ethe", 4) == 0)
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wth->file_encap = WTAP_ENCAP_ETHERNET;
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else if (memcmp(search_encap, "ATM/", 4) == 0)
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wth->file_encap = WTAP_ENCAP_ATM_RFC1483;
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else {
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*err = WTAP_ERR_UNSUPPORTED_ENCAP;
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*err_info = g_strdup_printf("radcom: network type \"%.4s\" unknown", search_encap);
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return -1;
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}
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#if 0
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bytes_read = file_read(&next_date, sizeof(struct frame_date), wth->fh);
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errno = WTAP_ERR_CANT_READ;
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if (bytes_read != sizeof(struct frame_date)) {
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goto read_error;
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}
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while (memcmp(&start_date, &next_date, 4)) {
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if (file_seek(wth->fh, 1-sizeof(struct frame_date), SEEK_CUR, err) == -1)
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return -1;
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(&next_date, sizeof(struct frame_date),
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wth->fh);
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if (bytes_read != sizeof(struct frame_date)) {
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goto read_error;
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}
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}
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#endif
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if (wth->file_encap == WTAP_ENCAP_ETHERNET) {
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if (file_seek(wth->fh, 294, SEEK_CUR, err) == -1)
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return -1;
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} else if (wth->file_encap == WTAP_ENCAP_LAPB) {
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if (file_seek(wth->fh, 297, SEEK_CUR, err) == -1)
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return -1;
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} else if (wth->file_encap == WTAP_ENCAP_ATM_RFC1483) {
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if (file_seek(wth->fh, 504, SEEK_CUR, err) == -1)
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return -1;
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}
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return 1;
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read_error:
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*err = file_error(wth->fh, err_info);
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if (*err != 0)
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return -1;
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return 0;
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}
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/* Read the next packet */
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static gboolean radcom_read(wtap *wth, int *err, gchar **err_info,
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gint64 *data_offset)
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{
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int ret;
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struct radcomrec_hdr hdr;
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guint16 data_length, real_length, length;
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guint32 sec;
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int bytes_read;
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struct tm tm;
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guint8 phdr[8];
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char fcs[2];
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/* Read record header. */
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*data_offset = file_tell(wth->fh);
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ret = radcom_read_rec_header(wth->fh, &hdr, err, err_info);
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if (ret <= 0) {
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/* Read error or EOF */
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return FALSE;
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}
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data_length = pletohs(&hdr.data_length);
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if (data_length == 0) {
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/*
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* The last record appears to have 0 in its "data_length"
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* field, but non-zero values in other fields, so we
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* check for that and treat it as an EOF indication.
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*/
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*err = 0;
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return FALSE;
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}
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length = pletohs(&hdr.length);
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real_length = pletohs(&hdr.real_length);
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if (wth->file_encap == WTAP_ENCAP_LAPB) {
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length -= 2; /* FCS */
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real_length -= 2;
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}
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wth->phdr.presence_flags = WTAP_HAS_TS|WTAP_HAS_CAP_LEN;
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wth->phdr.len = real_length;
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wth->phdr.caplen = length;
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tm.tm_year = pletohs(&hdr.date.year)-1900;
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tm.tm_mon = (hdr.date.month&0x0f)-1;
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tm.tm_mday = hdr.date.day;
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sec = pletohl(&hdr.date.sec);
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tm.tm_hour = sec/3600;
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tm.tm_min = (sec%3600)/60;
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tm.tm_sec = sec%60;
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tm.tm_isdst = -1;
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wth->phdr.ts.secs = mktime(&tm);
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wth->phdr.ts.nsecs = pletohl(&hdr.date.usec) * 1000;
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switch (wth->file_encap) {
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case WTAP_ENCAP_ETHERNET:
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/* XXX - is there an FCS? */
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wth->phdr.pseudo_header.eth.fcs_len = -1;
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break;
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case WTAP_ENCAP_LAPB:
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wth->phdr.pseudo_header.x25.flags = (hdr.dce & 0x1) ?
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0x00 : FROM_DCE;
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break;
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case WTAP_ENCAP_ATM_RFC1483:
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/*
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* XXX - is this stuff a pseudo-header?
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* The direction appears to be in the "hdr.dce" field.
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*/
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if (!radcom_read_rec_data(wth->fh, phdr, sizeof phdr, err,
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err_info))
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return FALSE; /* Read error */
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length -= 8;
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wth->phdr.len -= 8;
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wth->phdr.caplen -= 8;
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break;
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}
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/*
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* Read the packet data.
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*/
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buffer_assure_space(wth->frame_buffer, length);
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if (!radcom_read_rec_data(wth->fh,
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buffer_start_ptr(wth->frame_buffer), length, err, err_info))
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return FALSE; /* Read error */
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if (wth->file_encap == WTAP_ENCAP_LAPB) {
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/* Read the FCS.
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XXX - should we have some way of indicating the
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presence and size of an FCS to our caller?
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That'd let us handle other file types as well. */
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(&fcs, sizeof fcs, wth->fh);
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if (bytes_read != sizeof fcs) {
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*err = file_error(wth->fh, err_info);
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if (*err == 0)
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*err = WTAP_ERR_SHORT_READ;
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return FALSE;
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}
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}
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return TRUE;
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}
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static gboolean
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radcom_seek_read(wtap *wth, gint64 seek_off,
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struct wtap_pkthdr *pkhdr, guint8 *pd, int length,
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int *err, gchar **err_info)
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{
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union wtap_pseudo_header *pseudo_header = &pkhdr->pseudo_header;
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int ret;
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struct radcomrec_hdr hdr;
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guint8 phdr[8];
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if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
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return FALSE;
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/* Read record header. */
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ret = radcom_read_rec_header(wth->random_fh, &hdr, err, err_info);
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if (ret <= 0) {
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/* Read error or EOF */
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if (ret == 0) {
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/* EOF means "short read" in random-access mode */
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*err = WTAP_ERR_SHORT_READ;
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}
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return FALSE;
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}
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switch (wth->file_encap) {
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case WTAP_ENCAP_ETHERNET:
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/* XXX - is there an FCS? */
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pseudo_header->eth.fcs_len = -1;
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break;
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case WTAP_ENCAP_LAPB:
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pseudo_header->x25.flags = (hdr.dce & 0x1) ? 0x00 : FROM_DCE;
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break;
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case WTAP_ENCAP_ATM_RFC1483:
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/*
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* XXX - is this stuff a pseudo-header?
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* The direction appears to be in the "hdr.dce" field.
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*/
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if (!radcom_read_rec_data(wth->random_fh, phdr, sizeof phdr,
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err, err_info))
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return FALSE; /* Read error */
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break;
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}
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/*
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* Read the packet data.
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*/
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return radcom_read_rec_data(wth->random_fh, pd, length, err, err_info);
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}
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static int
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radcom_read_rec_header(FILE_T fh, struct radcomrec_hdr *hdr, int *err,
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gchar **err_info)
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{
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int bytes_read;
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(hdr, sizeof *hdr, fh);
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if (bytes_read != sizeof *hdr) {
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*err = file_error(fh, err_info);
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if (*err != 0)
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return -1;
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if (bytes_read != 0) {
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*err = WTAP_ERR_SHORT_READ;
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return -1;
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}
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return 0;
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}
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return 1;
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}
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static gboolean
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radcom_read_rec_data(FILE_T fh, guint8 *pd, int length, int *err,
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gchar **err_info)
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{
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int bytes_read;
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(pd, length, fh);
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if (bytes_read != length) {
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*err = file_error(fh, err_info);
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if (*err == 0)
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*err = WTAP_ERR_SHORT_READ;
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return FALSE;
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}
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return TRUE;
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}
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