cse 2410 f13 wireshark

/* dct3trace.c

 * Routines for reading signalling traces generated by Gammu (www.gammu.org)

 * from Nokia DCT3 phones in Netmonitor mode.

 *

 * gammu --nokiadebug nhm5_587.txt v18-19

 *

 * Duncan Salerno <duncan.salerno@googlemail.com>

 *

 * $Id$

 *

 * Wiretap Library

 * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#include "config.h"

#include "wtap-int.h"

#include "buffer.h"

#include "dct3trace.h"

#include "file_wrappers.h"

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <ctype.h>

/*

   Example downlink data:

<?xml version="1.0"?>

<dump>

<l1 direction="down" logicalchannel="96" physicalchannel="19" sequence="268116" error="0" timeshift="2992" bsic="22" data="31063F100DD0297A53E1020103C802398E0B2B2B2B2B2B" >

<l2 data="063F100DD0297A53E1020103" rest="C802398E0B2B2B2B2B2B" >

</l2>

</l1>

</dump>

   Example uplink data (no raw L1):

<?xml version="1.0"?>

<dump>

<l1 direction="up" logicalchannel="112" >

<l2 type="U" subtype="Unknown" p="0" data="061500400000000000000000000000000000" >

</l2>

</l1>

</dump>

 */

/* Magic text to check */

static const char dct3trace_magic_line1[] = "<?xml version=\"1.0\"?>";

static const char dct3trace_magic_line2[] = "<dump>";

static const char dct3trace_magic_record_start[]  = "<l1 ";

static const char dct3trace_magic_record_end[]  = "</l1>";

static const char dct3trace_magic_l2_start[]  = "<l2 ";

static const char dct3trace_magic_l2_end[]  = "</l2>";

static const char dct3trace_magic_end[]  = "</dump>";

#define MAX_PACKET_LEN 23

static gboolean dct3trace_read(wtap *wth, int *err, gchar **err_info,

        gint64 *data_offset);

static gboolean dct3trace_seek_read(wtap *wth, gint64 seek_off,

        struct wtap_pkthdr *phdr, Buffer *buf, int len,

        int *err, gchar **err_info);

/*

 * Following 3 functions taken from gsmdecode-0.7bis, with permission - http://wiki.thc.org/gsm

 */

static int

hc2b(unsigned char hex)

{

        hex = tolower(hex);

        if ((hex >= '0') && (hex <= '9'))

                return hex - '0';

        if ((hex >= 'a') && (hex <= 'f'))

                return hex - 'a' + 10;

        return -1;

}

static int

hex2bin(guint8 *out, guint8 *out_end, char *in)

{

        guint8 *out_start = out;

        int is_low = 0;

        int c;

        while (*in != '\0')

        {

                c = hc2b(*(unsigned char *)in);

                if (c < 0)

                {

                        in++;

                        continue;

                }

                if (out == out_end)

                {

                        /* Too much data */

                        return -1;

                }

                if (is_low == 0)

                {

                        *out = c << 4;

                        is_low = 1;

                } else {

                        *out |= (c & 0x0f);

                        is_low = 0;

                        out++;

                }

                in++;

        }

        return (int)(out - out_start);

}

static int

xml_get_int(int *val, const char *str, const char *pattern)

{

        const char *ptr;

        char *start, *end;

        char buf[32];

        ptr = strstr(str, pattern);

        if (ptr == NULL)

                return -1;

        start = strchr(ptr, '"');

        if (start == NULL)

                return -2;

        start++;

        end = strchr(start, '"');

        if (end == NULL)

                return -3;

        if (end - start > 31)

                return -4;

        memcpy(buf, start, end - start);

        buf[end - start] = '\0';

        *val = atoi(buf);

        return 0;

}

int dct3trace_open(wtap *wth, int *err, gchar **err_info)

{

        char line1[64], line2[64];

        /* Look for Gammu DCT3 trace header */

        if (file_gets(line1, sizeof(line1), wth->fh) == NULL ||

                file_gets(line2, sizeof(line2), wth->fh) == NULL)

        {

                *err = file_error(wth->fh, err_info);

                if (*err != 0 && *err != WTAP_ERR_SHORT_READ)

                        return -1;

                return 0;

        }

        /* Don't compare line endings */

        if( strncmp(dct3trace_magic_line1, line1, strlen(dct3trace_magic_line1)) != 0 ||

                strncmp(dct3trace_magic_line2, line2, strlen(dct3trace_magic_line2)) != 0)

        {

                return 0;

        }

        wth->file_encap = WTAP_ENCAP_GSM_UM;

        wth->file_type = WTAP_FILE_DCT3TRACE;

        wth->snapshot_length = 0; /* not known */

        wth->subtype_read = dct3trace_read;

        wth->subtype_seek_read = dct3trace_seek_read;

        wth->tsprecision = WTAP_FILE_TSPREC_SEC;

        return 1;

}

static gboolean dct3trace_get_packet(FILE_T fh, struct wtap_pkthdr *phdr,

        Buffer *buf, int *err, gchar **err_info)

{

        char line[1024];

        guint8 databuf[MAX_PACKET_LEN], *bufp;

        gboolean have_data = FALSE;

        int len = 0;

        bufp = &databuf[0];

        while (file_gets(line, sizeof(line), fh) != NULL)

        {

                if( memcmp(dct3trace_magic_end, line, strlen(dct3trace_magic_end)) == 0 )

                {

                        /* Return on end of file </dump> */

                        *err = 0;

                        return FALSE;

                }

                else if( memcmp(dct3trace_magic_record_end, line, strlen(dct3trace_magic_record_end)) == 0 )

                {

                        /* Return on end of record </l1> */

                        if( have_data )

                        {

                                /* We've got a full packet! */

                                phdr->presence_flags = 0; /* no time stamp, no separate "on the wire" length */

                                phdr->ts.secs = 0;

                                phdr->ts.nsecs = 0;

                                phdr->caplen = len;

                                phdr->len = len;

                                *err = 0;

                                /* Make sure we have enough room for the packet */

                                buffer_assure_space(buf, phdr->caplen);

                                memcpy( buffer_start_ptr(buf), databuf, phdr->caplen );

                                return TRUE;

                        }

                        else

                        {

                                /* If not got any data return error */

                                *err = WTAP_ERR_BAD_FILE;

                                *err_info = g_strdup_printf("dct3trace: record without data");

                                return FALSE;

                        }

                }

                else if( memcmp(dct3trace_magic_record_start, line, strlen(dct3trace_magic_record_start)) == 0 )

                {

                        /* Parse L1 header <l1 ...>*/

                        int channel, tmp;

                        char *ptr;

                        phdr->pseudo_header.gsm_um.uplink = !strstr(line, "direction=\"down\"");

                        if (xml_get_int(&channel, line, "logicalchannel") != 0)

                                goto baddata;

                        /* Parse downlink only fields */

                        if( !phdr->pseudo_header.gsm_um.uplink )

                        {

                                if (xml_get_int(&tmp, line, "physicalchannel") != 0)

                                        goto baddata;

                                phdr->pseudo_header.gsm_um.arfcn = tmp;

                                if (xml_get_int(&tmp, line, "sequence") != 0)

                                        goto baddata;

                                phdr->pseudo_header.gsm_um.tdma_frame = tmp;

                                if (xml_get_int(&tmp, line, "bsic") != 0)

                                        goto baddata;

                                phdr->pseudo_header.gsm_um.bsic = tmp;

                                if (xml_get_int(&tmp, line, "error") != 0)

                                        goto baddata;

                                phdr->pseudo_header.gsm_um.error = tmp;

                                if (xml_get_int(&tmp, line, "timeshift") != 0)

                                        goto baddata;

                                phdr->pseudo_header.gsm_um.timeshift = tmp;

                        }

                        switch( channel )

                        {

                                case 128: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_SDCCH; break;

                                case 112: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_SACCH; break;

                                case 176: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_FACCH; break;

                                case 96: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_CCCH; break;

                                case 80: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_BCCH; break;

                                default: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_UNKNOWN; break;

                        }

                        /* Read data (if have it) into databuf */

                        ptr = strstr(line, "data=\"");

                        if( ptr )

                        {

                                have_data = TRUE; /* If has data... */

                                len = hex2bin(bufp, &databuf[MAX_PACKET_LEN], ptr+6);

                                if (len == -1)

                                {

                                        *err = WTAP_ERR_BAD_FILE;

                                        *err_info = g_strdup_printf("dct3trace: record length %d too long", phdr->caplen);

                                        return FALSE;

                                }

                        }

                }

                else if( !have_data && memcmp(dct3trace_magic_l2_start, line, strlen(dct3trace_magic_l2_start)) == 0 )

                {

                        /* For uplink packets we might not get the raw L1, so have to recreate it from the L2 */

                        /* Parse L2 header if didn't get data from L1 <l2 ...> */

                        int data_len;

                        char *ptr = strstr(line, "data=\"");

                        if( !ptr )

                        {

                                continue;

                        }

                        have_data = TRUE;

                        /*

                         * We know we have no data already, so we know

                         * we have enough room for the header.

                         */

                        if( phdr->pseudo_header.gsm_um.channel == GSM_UM_CHANNEL_SACCH || phdr->pseudo_header.gsm_um.channel == GSM_UM_CHANNEL_FACCH || phdr->pseudo_header.gsm_um.channel == GSM_UM_CHANNEL_SDCCH )

                        {

                                /* Add LAPDm B header */

                                memset(bufp, 0x1, 2);

                                len = 3;

                        }

                        else

                        {

                                /* Add LAPDm Bbis header */

                                len = 1;

                        }

                        bufp += len;

                        data_len = hex2bin(bufp, &databuf[MAX_PACKET_LEN], ptr+6);

                        if (data_len == -1)

                        {

                                *err = WTAP_ERR_BAD_FILE;

                                *err_info = g_strdup_printf("dct3trace: record length %d too long", phdr->caplen);

                                return FALSE;

                        }

                        len += data_len;

                        /* Add LAPDm length byte */

                        *(bufp - 1) = data_len << 2 | 0x1;

                }

        }

        *err = file_error(fh, err_info);

        if (*err == 0)

        {

                *err = WTAP_ERR_SHORT_READ;

        }

        return FALSE;

baddata:

        *err = WTAP_ERR_BAD_FILE;

        *err_info = g_strdup_printf("dct3trace: record missing mandatory attributes");

        return FALSE;

}

/* Find the next packet and parse it; called from wtap_read(). */

static gboolean dct3trace_read(wtap *wth, int *err, gchar **err_info,

    gint64 *data_offset)

{

        *data_offset = file_tell(wth->fh);

        return dct3trace_get_packet(wth->fh, &wth->phdr, wth->frame_buffer,

            err, err_info);

}

/* Used to read packets in random-access fashion */

static gboolean dct3trace_seek_read(wtap *wth, gint64 seek_off,

        struct wtap_pkthdr *phdr, Buffer *buf, int len _U_,

        int *err, gchar **err_info)

{

        if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)

        {

                return FALSE;

        }

        return dct3trace_get_packet(wth->random_fh, phdr, buf, err, err_info);

}