![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
385 lines
9.6 KiB
C
385 lines
9.6 KiB
C
/* dct3trace.c
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* Routines for reading signalling traces generated by Gammu (www.gammu.org)
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* from Nokia DCT3 phones in Netmonitor mode.
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*
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* gammu --nokiadebug nhm5_587.txt v18-19
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*
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* Duncan Salerno <duncan.salerno@googlemail.com>
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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 "wtap-int.h"
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#include "buffer.h"
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#include "dct3trace.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 <ctype.h>
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/*
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Example downlink data:
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<?xml version="1.0"?>
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<dump>
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<l1 direction="down" logicalchannel="96" physicalchannel="19" sequence="268116" error="0" timeshift="2992" bsic="22" data="31063F100DD0297A53E1020103C802398E0B2B2B2B2B2B" >
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<l2 data="063F100DD0297A53E1020103" rest="C802398E0B2B2B2B2B2B" >
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</l2>
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</l1>
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</dump>
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Example uplink data (no raw L1):
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<?xml version="1.0"?>
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<dump>
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<l1 direction="up" logicalchannel="112" >
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<l2 type="U" subtype="Unknown" p="0" data="061500400000000000000000000000000000" >
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</l2>
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</l1>
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</dump>
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*/
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/* Magic text to check */
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static const char dct3trace_magic_line1[] = "<?xml version=\"1.0\"?>";
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static const char dct3trace_magic_line2[] = "<dump>";
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static const char dct3trace_magic_record_start[] = "<l1 ";
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static const char dct3trace_magic_record_end[] = "</l1>";
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static const char dct3trace_magic_l2_start[] = "<l2 ";
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static const char dct3trace_magic_l2_end[] = "</l2>";
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static const char dct3trace_magic_end[] = "</dump>";
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#define MAX_PACKET_LEN 23
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static gboolean dct3trace_read(wtap *wth, int *err, gchar **err_info,
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gint64 *data_offset);
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static gboolean dct3trace_seek_read(wtap *wth, gint64 seek_off,
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struct wtap_pkthdr *phdr, guint8 *pd, int len,
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int *err, gchar **err_info);
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/*
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* Following 3 functions taken from gsmdecode-0.7bis, with permission - http://wiki.thc.org/gsm
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*/
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static int
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hc2b(unsigned char hex)
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{
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hex = tolower(hex);
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if ((hex >= '0') && (hex <= '9'))
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return hex - '0';
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if ((hex >= 'a') && (hex <= 'f'))
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return hex - 'a' + 10;
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return -1;
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}
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static int
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hex2bin(unsigned char *out, unsigned char *in)
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{
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unsigned char *out_start = out;
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unsigned char *end = in + strlen((char *)in);
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int is_low = 0;
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int c;
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/* Clamp to maximum packet size */
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if (end - in > MAX_PACKET_LEN*2) /* As we're reading nibbles */
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end = in + MAX_PACKET_LEN*2;
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while (in < end)
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{
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c = hc2b(in[0]);
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if (c < 0)
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{
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in++;
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continue;
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}
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if (is_low == 0)
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{
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out[0] = c << 4;
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is_low = 1;
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} else {
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out[0] |= (c & 0x0f);
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is_low = 0;
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out++;
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}
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in++;
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}
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return (int)(out - out_start);
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}
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static int
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xml_get_int(int *val, const unsigned char *str, const unsigned char *pattern)
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{
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const char *ptr;
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char *start, *end;
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char buf[32];
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ptr = strstr((const char *)str, (const char *)pattern);
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if (ptr == NULL)
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return -1;
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start = strchr(ptr, '"');
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if (start == NULL)
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return -2;
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start++;
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end = strchr(start, '"');
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if (end == NULL)
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return -3;
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if (end - start > 31)
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return -4;
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memcpy(buf, start, end - start);
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buf[end - start] = '\0';
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*val = atoi(buf);
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return 0;
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}
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int dct3trace_open(wtap *wth, int *err, gchar **err_info)
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{
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char line1[64], line2[64];
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/* Look for Gammu DCT3 trace header */
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if (file_gets(line1, sizeof(line1), wth->fh) == NULL ||
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file_gets(line2, sizeof(line2), wth->fh) == NULL)
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{
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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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/* Don't compare line endings */
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if( strncmp(dct3trace_magic_line1, line1, strlen(dct3trace_magic_line1)) != 0 ||
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strncmp(dct3trace_magic_line2, line2, strlen(dct3trace_magic_line2)) != 0)
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{
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return 0;
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}
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wth->file_encap = WTAP_ENCAP_GSM_UM;
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wth->file_type = WTAP_FILE_DCT3TRACE;
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wth->snapshot_length = 0; /* not known */
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wth->subtype_read = dct3trace_read;
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wth->subtype_seek_read = dct3trace_seek_read;
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wth->tsprecision = WTAP_FILE_TSPREC_SEC;
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return 1;
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}
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static gboolean dct3trace_get_packet(FILE_T fh, union wtap_pseudo_header *pseudo_header,
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unsigned char *buf, int *len, int *err, gchar **err_info)
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{
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unsigned char line[1024];
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gboolean have_data = FALSE;
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while (file_gets(line, sizeof(line), fh) != NULL)
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{
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if( memcmp(dct3trace_magic_end, line, strlen(dct3trace_magic_end)) == 0 )
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{
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/* Return on end of file </dump> */
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*err = 0;
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return FALSE;
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}
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else if( memcmp(dct3trace_magic_record_end, line, strlen(dct3trace_magic_record_end)) == 0 )
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{
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/* Return on end of record </l1> */
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if( have_data )
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{
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*err = 0;
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return TRUE;
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}
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else
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{
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/* If not got any data return error */
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*err = WTAP_ERR_BAD_FILE;
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*err_info = g_strdup_printf("dct3trace: record without data");
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return FALSE;
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}
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}
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else if( memcmp(dct3trace_magic_record_start, line, strlen(dct3trace_magic_record_start)) == 0 )
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{
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/* Parse L1 header <l1 ...>*/
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int channel, tmp;
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char *ptr;
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pseudo_header->gsm_um.uplink = !strstr(line, "direction=\"down\"");
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if (xml_get_int(&channel, line, "logicalchannel") != 0)
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goto baddata;
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/* Parse downlink only fields */
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if( !pseudo_header->gsm_um.uplink )
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{
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if (xml_get_int(&tmp, line, "physicalchannel") != 0)
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goto baddata;
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pseudo_header->gsm_um.arfcn = tmp;
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if (xml_get_int(&tmp, line, "sequence") != 0)
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goto baddata;
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pseudo_header->gsm_um.tdma_frame = tmp;
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if (xml_get_int(&tmp, line, "bsic") != 0)
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goto baddata;
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pseudo_header->gsm_um.bsic = tmp;
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if (xml_get_int(&tmp, line, "error") != 0)
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goto baddata;
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pseudo_header->gsm_um.error = tmp;
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if (xml_get_int(&tmp, line, "timeshift") != 0)
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goto baddata;
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pseudo_header->gsm_um.timeshift = tmp;
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}
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switch( channel )
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{
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case 128: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_SDCCH; break;
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case 112: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_SACCH; break;
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case 176: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_FACCH; break;
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case 96: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_CCCH; break;
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case 80: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_BCCH; break;
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default: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_UNKNOWN; break;
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}
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/* Read data (if have it) into buf */
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ptr = strstr(line, "data=\"");
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if( ptr )
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{
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have_data = TRUE; /* If has data... */
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*len = hex2bin(buf, ptr+6);
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}
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}
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else if( !have_data && memcmp(dct3trace_magic_l2_start, line, strlen(dct3trace_magic_l2_start)) == 0 )
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{
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/* For uplink packets we might not get the raw L1, so have to recreate it from the L2 */
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/* Parse L2 header if didn't get data from L1 <l2 ...> */
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int data_len = 0;
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char *ptr = strstr(line, "data=\"");
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if( !ptr )
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{
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continue;
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}
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have_data = TRUE;
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if( pseudo_header->gsm_um.channel == GSM_UM_CHANNEL_SACCH || pseudo_header->gsm_um.channel == GSM_UM_CHANNEL_FACCH || pseudo_header->gsm_um.channel == GSM_UM_CHANNEL_SDCCH )
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{
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/* Add LAPDm B header */
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memset(buf, 0x1, 2);
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*len = 3;
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}
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else
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{
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/* Add LAPDm Bbis header */
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*len = 1;
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}
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buf += *len;
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data_len = hex2bin(buf, ptr+6);
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*len += data_len;
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/* Add LAPDm length byte */
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*(buf - 1) = data_len << 2 | 0x1;
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}
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}
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*err = file_error(fh, err_info);
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if (*err == 0)
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{
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*err = WTAP_ERR_SHORT_READ;
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}
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return FALSE;
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baddata:
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*err = WTAP_ERR_BAD_FILE;
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*err_info = g_strdup_printf("dct3trace: record missing mandatory attributes");
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return FALSE;
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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 dct3trace_read(wtap *wth, int *err, gchar **err_info,
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gint64 *data_offset)
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{
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guint64 offset = file_tell(wth->fh);
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int buf_len;
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unsigned char buf[MAX_PACKET_LEN];
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if( !dct3trace_get_packet(wth->fh, &wth->phdr.pseudo_header, buf, &buf_len, err, err_info) )
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{
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return FALSE;
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}
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/* We've got a full packet! */
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wth->phdr.presence_flags = 0; /* no time stamp, no separate "on the wire" length */
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wth->phdr.ts.secs = 0;
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wth->phdr.ts.nsecs = 0;
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wth->phdr.caplen = buf_len;
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wth->phdr.len = buf_len;
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/* Make sure we have enough room for the packet */
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buffer_assure_space(wth->frame_buffer, buf_len);
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memcpy( buffer_start_ptr(wth->frame_buffer), buf, buf_len );
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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 dct3trace_seek_read (wtap *wth, gint64 seek_off,
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struct wtap_pkthdr *phdr, guint8 *pd, int len,
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int *err, gchar **err_info)
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{
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union wtap_pseudo_header *pseudo_header = &phdr->pseudo_header;
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int buf_len;
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unsigned char buf[MAX_PACKET_LEN];
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if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
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{
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return FALSE;
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}
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if( !dct3trace_get_packet(wth->random_fh, pseudo_header, buf, &buf_len, err, err_info) )
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{
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return FALSE;
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}
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if( len != buf_len && len != -1 )
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{
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*err = WTAP_ERR_BAD_FILE;
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*err_info = g_strdup_printf("dct3trace: requested length %d doesn't match record length %d",
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len, buf_len);
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return FALSE;
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}
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if( buf_len > MAX_PACKET_LEN)
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{
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*err = WTAP_ERR_BAD_FILE;
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*err_info = g_strdup_printf("dct3trace: record length %d too long", buf_len);
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return FALSE;
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}
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memcpy( pd, buf, buf_len );
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return TRUE;
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}
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