723c80ea90
- automatic adjustment depending on file format - manual adjustment through menu items save the setting in the recent file svn path=/trunk/; revision=15534
318 lines
8.7 KiB
C
318 lines
8.7 KiB
C
/* eyesdn.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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "wtap-int.h"
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#include "buffer.h"
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#include "eyesdn.h"
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#include "file_wrappers.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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/* This module reads the output of the EyeSDN USB S0/E1 ISDN probes
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* They store HDLC frames of D and B channels in a binary format
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* The fileformat is
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*
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* 1-6 Byte: EyeSDN - Magic
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* 7-n Byte: Frames
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*
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* Each Frame starts with the 0xff Flag byte
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* - Bytes 0-2: timestamp (long usec in network byte order)
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* - Bytes 3-7: timestamp (40bits sec since 1970 in network byte order)
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* - Byte 8: channel (0 for D channel, 1-30 for B1-B30)
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* - Byte 9: Sender (0 NT, 1 TE)
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* - Byte 10-11: frame size in bytes
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* - Byte 12-n: Frame Payload
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*
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* All multibyte values are represented in network byte order
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* The frame is terminated with a flag character (0xff)
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* bytes 0xff within a frame are escaped using the 0xfe escape character
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* the byte following the escape character is decremented by two:
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* so 0xfe 0xfd is actually a 0xff
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* Characters that need to be escaped are 0xff and 0xfe
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*/
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static int esc_read(guint8 *buf, int len, FILE_T fh)
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{
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int i;
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int value;
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for(i=0; i<len; i++) {
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value=file_getc(fh);
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if(value==-1)
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return -2; /* EOF or error */
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if(value==0xff)
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return -1; /* error !!, read into next frame */
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if(value==0xfe) {
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/* we need to escape */
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value=file_getc(fh);
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if(value==-1)
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return -2;
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value+=2;
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}
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buf[i]=value;
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}
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return i;
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}
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/* Magic text to check for eyesdn-ness of file */
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static const unsigned char eyesdn_hdr_magic[] =
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{ 'E', 'y', 'e', 'S', 'D', 'N'};
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#define EYESDN_HDR_MAGIC_SIZE (sizeof(eyesdn_hdr_magic) / sizeof(eyesdn_hdr_magic[0]))
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/* Size of a record header */
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#define EYESDN_HDR_LENGTH 12
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/*
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* XXX - is this the biggest packet we can get?
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*/
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#define EYESDN_MAX_PACKET_LEN 16384
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static gboolean eyesdn_read(wtap *wth, int *err, gchar **err_info,
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long *data_offset);
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static gboolean eyesdn_seek_read(wtap *wth, long seek_off,
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union wtap_pseudo_header *pseudo_header, guint8 *pd, int len,
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int *err, gchar **err_info);
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static gboolean parse_eyesdn_packet_data(FILE_T fh, int pkt_len, guint8* buf,
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int *err, gchar **err_info);
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static int parse_eyesdn_rec_hdr(wtap *wth, FILE_T fh,
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union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info);
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/* Seeks to the beginning of the next packet, and returns the
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byte offset. Returns -1 on failure, and sets "*err" to the error. */
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static long eyesdn_seek_next_packet(wtap *wth, int *err)
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{
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int byte;
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long cur_off;
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while ((byte = file_getc(wth->fh)) != EOF) {
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if (byte == 0xff) {
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cur_off = file_tell(wth->fh);
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if (cur_off == -1) {
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/* Error. */
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*err = file_error(wth->fh);
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return -1;
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}
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return cur_off;
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}
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}
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if (file_eof(wth->fh)) {
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/* We got an EOF. */
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*err = 0;
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} else {
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/* We (presumably) got an error (there's no equivalent to "ferror()"
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in zlib, alas, so we don't have a wrapper to check for an error). */
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*err = file_error(wth->fh);
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}
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return -1;
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}
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int eyesdn_open(wtap *wth, int *err, gchar **err_info _U_)
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{
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int bytes_read;
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char magic[EYESDN_HDR_MAGIC_SIZE];
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/* Look for eyesdn header */
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errno = WTAP_ERR_CANT_READ;
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bytes_read = file_read(&magic, 1, sizeof magic, wth->fh);
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if (bytes_read != sizeof magic) {
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*err = file_error(wth->fh);
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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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if (memcmp(magic, eyesdn_hdr_magic, EYESDN_HDR_MAGIC_SIZE) != 0)
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return 0;
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wth->data_offset = 0;
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wth->file_encap = WTAP_ENCAP_ISDN;
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wth->file_type = WTAP_FILE_EYESDN;
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wth->snapshot_length = 0; /* not known */
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wth->subtype_read = eyesdn_read;
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wth->subtype_seek_read = eyesdn_seek_read;
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wth->tsprecision = WTAP_FILE_TSPREC_USEC;
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return 1;
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}
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/* Find the next packet and parse it; called from wtap_read(). */
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static gboolean eyesdn_read(wtap *wth, int *err, gchar **err_info,
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long *data_offset)
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{
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long offset;
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guint8 *buf;
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int pkt_len;
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/* Find the next packet */
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offset = eyesdn_seek_next_packet(wth, err);
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if (offset < 1)
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return FALSE;
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/* Parse the header */
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pkt_len = parse_eyesdn_rec_hdr(wth, wth->fh, &wth->pseudo_header, err,
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err_info);
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if (pkt_len == -1)
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return FALSE;
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/* Make sure we have enough room for the packet */
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buffer_assure_space(wth->frame_buffer, EYESDN_MAX_PACKET_LEN);
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buf = buffer_start_ptr(wth->frame_buffer);
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/* Read the packet data */
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if (!parse_eyesdn_packet_data(wth->fh, pkt_len, buf, err, err_info))
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return FALSE;
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wth->data_offset = offset;
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*data_offset = offset;
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return TRUE;
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}
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/* Used to read packets in random-access fashion */
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static gboolean
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eyesdn_seek_read (wtap *wth, long seek_off,
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union wtap_pseudo_header *pseudo_header, guint8 *pd, int len,
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int *err, gchar **err_info)
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{
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int pkt_len;
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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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pkt_len = parse_eyesdn_rec_hdr(NULL, wth->random_fh, pseudo_header,
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err, err_info);
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if (pkt_len != len) {
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if (pkt_len != -1) {
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*err = WTAP_ERR_BAD_RECORD;
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*err_info = g_strdup_printf("eyesdn: requested length %d doesn't match length %d",
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len, pkt_len);
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}
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return FALSE;
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}
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return parse_eyesdn_packet_data(wth->random_fh, pkt_len, pd, err,
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err_info);
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}
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/* Parses a packet record header. */
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static int
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parse_eyesdn_rec_hdr(wtap *wth, FILE_T fh,
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union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info)
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{
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guint8 hdr[EYESDN_HDR_LENGTH];
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unsigned long secs, usecs;
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int pkt_len;
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unsigned int channel, direction;
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/* Our file pointer should be at the summary information header
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* for a packet. Read in that header and extract the useful
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* information.
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*/
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if (esc_read(hdr, EYESDN_HDR_LENGTH, fh) != EYESDN_HDR_LENGTH) {
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*err = file_error(fh);
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if (*err == 0)
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*err = WTAP_ERR_SHORT_READ;
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return -1;
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}
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/* extract information from header */
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usecs = ((unsigned long) hdr[0]);
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usecs = (usecs << 8) | ((unsigned long) hdr[1]);
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usecs = (usecs << 8) | ((unsigned long) hdr[2]);
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#ifdef TV64BITS
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secs = ((unsigned long) hdr[3]);
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#else
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secs = 0;
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#endif
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secs = (secs << 8) | ((unsigned long) hdr[4]);
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secs = (secs << 8) | ((unsigned long) hdr[5]);
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secs = (secs << 8) | ((unsigned long) hdr[6]);
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secs = (secs << 8) | ((unsigned long) hdr[7]);
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channel = hdr[8];
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direction = hdr[9];
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pkt_len = ((unsigned long) hdr[10]);
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pkt_len = (pkt_len << 8) | ((unsigned long) hdr[11]);
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/* sanity checks */
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if(channel>30) {
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*err = WTAP_ERR_BAD_RECORD;
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*err_info = g_strdup_printf("eyesdn: bad channel number %u",
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channel);
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return -1;
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}
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if(direction>1) {
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*err = WTAP_ERR_BAD_RECORD;
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*err_info = g_strdup_printf("eyesdn: bad direction value %u",
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direction);
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return -1;
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}
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if(pkt_len > EYESDN_MAX_PACKET_LEN) {
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*err = WTAP_ERR_BAD_RECORD;
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*err_info = g_strdup_printf("eyesdn: File has %u-byte packet, bigger than maximum of %u",
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pkt_len, EYESDN_MAX_PACKET_LEN);
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return -1;
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}
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if (wth) {
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wth->phdr.ts.secs = secs;
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wth->phdr.ts.nsecs = usecs * 1000;
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wth->phdr.caplen = pkt_len;
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wth->phdr.len = pkt_len;
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}
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pseudo_header->isdn.uton = direction;
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pseudo_header->isdn.channel = channel;
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return pkt_len;
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}
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/* read a packet */
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static gboolean
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parse_eyesdn_packet_data(FILE_T fh, int pkt_len, guint8* buf, 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 = esc_read(buf, pkt_len, fh);
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if (bytes_read != pkt_len) {
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if (bytes_read == -2) {
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*err = file_error(fh);
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if (*err == 0)
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*err = WTAP_ERR_SHORT_READ;
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} else if (bytes_read == -1) {
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*err = WTAP_ERR_BAD_RECORD;
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*err_info = g_strdup("eyesdn: No flag character seen in frame");
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} else
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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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