wiretap/dct3trace.c

   1 /* dct3trace.c
   2  * Routines for reading signalling traces generated by Gammu (www.gammu.org)
   3  * from Nokia DCT3 phones in Netmonitor mode.
   4  *
   5  * gammu --nokiadebug nhm5_587.txt v18-19
   6  *
   7  * Duncan Salerno <duncan.salerno@googlemail.com>
   8  *
   9  * $Id$
  10  *
  11  * Wiretap Library
  12  * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  27  */
  28
  29 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif
  32 #include "wtap-int.h"
  33 #include "buffer.h"
  34 #include "dct3trace.h"
  35 #include "file_wrappers.h"
  36
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <ctype.h>
  41
  42
  43 /*
  44    Example downlink data:
  45
  46 <?xml version="1.0"?>
  47 <dump>
  48 <l1 direction="down" logicalchannel="96" physicalchannel="19" sequence="268116" error="0" timeshift="2992" bsic="22" data="31063F100DD0297A53E1020103C802398E0B2B2B2B2B2B" >
  49 <l2 data="063F100DD0297A53E1020103" rest="C802398E0B2B2B2B2B2B" >
  50 </l2>
  51 </l1>
  52 </dump>
  53
  54    Example uplink data (no raw L1):
  55
  56 <?xml version="1.0"?>
  57 <dump>
  58 <l1 direction="up" logicalchannel="112" >
  59 <l2 type="U" subtype="Unknown" p="0" data="061500400000000000000000000000000000" >
  60 </l2>
  61 </l1>
  62 </dump>
  63
  64  */
  65
  66
  67 /* Magic text to check */
  68 static const char dct3trace_magic_line1[] = "<?xml version=\"1.0\"?>";
  69 static const char dct3trace_magic_line2[] = "<dump>";
  70 static const char dct3trace_magic_record_start[]  = "<l1 ";
  71 static const char dct3trace_magic_record_end[]  = "</l1>";
  72 static const char dct3trace_magic_l2_start[]  = "<l2 ";
  73 static const char dct3trace_magic_l2_end[]  = "</l2>";
  74 static const char dct3trace_magic_end[]  = "</dump>";
  75
  76 #define MAX_PACKET_LEN 23
  77
  78 static gboolean dct3trace_read(wtap *wth, int *err, gchar **err_info,
  79         gint64 *data_offset);
  80 static gboolean dct3trace_seek_read(wtap *wth, gint64 seek_off,
  81         union wtap_pseudo_header *pseudo_header, guint8 *pd, int len,
  82         int *err, gchar **err_info);
  83
  84 /*
  85  * Following 3 functions taken from gsmdecode-0.7bis, with permission - http://wiki.thc.org/gsm
  86  */
  87
  88 static int
  89 hc2b(unsigned char hex)
  90 {
  91         hex = tolower(hex);
  92         if ((hex >= '0') && (hex <= '9'))
  93                 return hex - '0';
  94         if ((hex >= 'a') && (hex <= 'f'))
  95                 return hex - 'a' + 10;
  96         return -1;
  97 }
  98
  99 static int
 100 hex2bin(unsigned char *out, unsigned char *in)
 101 {
 102         unsigned char *out_start = out;
 103         unsigned char *end = in + strlen((char *)in);
 104         int is_low = 0;
 105         int c;
 106
 107         /* Clamp to maximum packet size */
 108         if (end - in > MAX_PACKET_LEN*2) /* As we're reading nibbles */
 109                 end = in + MAX_PACKET_LEN*2;
 110
 111         while (in < end)
 112         {
 113                 c = hc2b(in[0]);
 114                 if (c < 0)
 115                 {
 116                         in++;
 117                         continue;
 118                 }
 119                 if (is_low == 0)
 120                 {
 121                         out[0] = c << 4;
 122                         is_low = 1;
 123                 } else {
 124                         out[0] |= (c & 0x0f);
 125                         is_low = 0;
 126                         out++;
 127                 }
 128                 in++;
 129         }
 130
 131         return (int)(out - out_start);
 132 }
 133
 134 static int
 135 xml_get_int(int *val, const unsigned char *str, const unsigned char *pattern)
 136 {
 137         const char *ptr;
 138         char *start, *end;
 139         char buf[32];
 140
 141         ptr = strstr((const char *)str, (const char *)pattern);
 142         if (ptr == NULL)
 143                 return -1;
 144         start = strchr(ptr, '"');
 145         if (start == NULL)
 146                 return -2;
 147         start++;
 148         end = strchr(start, '"');
 149         if (end == NULL)
 150                 return -3;
 151         if (end - start > 31)
 152                 return -4;
 153
 154         memcpy(buf, start, end - start);
 155         buf[end - start] = '\0';
 156         *val = atoi(buf);
 157         return 0;
 158 }
 159
 160
 161 /* Look through the first part of a file to see if this is
 162  * a DCT3 trace file.
 163  *
 164  * Returns TRUE if it is, FALSE if it isn't or if we get an I/O error;
 165  * if we get an I/O error, "*err" will be set to a non-zero value
 166  * and "*err_info" will be set to null or an additional error string.
 167  */
 168 static gboolean dct3trace_check_file_type(wtap *wth, int *err, gchar **err_info)
 169 {
 170         char line1[64], line2[64];
 171
 172         if (file_gets(line1, sizeof(line1), wth->fh) != NULL &&
 173                 file_gets(line2, sizeof(line2), wth->fh) != NULL)
 174         {
 175                 /* Don't compare line endings */
 176                 if( strncmp(dct3trace_magic_line1, line1, strlen(dct3trace_magic_line1)) == 0 &&
 177                         strncmp(dct3trace_magic_line2, line2, strlen(dct3trace_magic_line2)) == 0)
 178                 {
 179                         return TRUE;
 180                 }
 181         }
 182         /* EOF or error. */
 183         else
 184         {
 185                 if (file_eof(wth->fh))
 186                         *err = 0;
 187                 else
 188                         *err = file_error(wth->fh, err_info);
 189         }
 190
 191         return FALSE;
 192 }
 193
 194
 195 int dct3trace_open(wtap *wth, int *err, gchar **err_info)
 196 {
 197         /* Look for Gammu DCT3 trace header */
 198         if (!dct3trace_check_file_type(wth, err, err_info))
 199         {
 200                 if (*err == 0)
 201                         return 0;
 202                 else
 203                         return -1;
 204         }
 205
 206         wth->data_offset = 0;
 207         wth->file_encap = WTAP_ENCAP_GSM_UM;
 208         wth->file_type = WTAP_FILE_DCT3TRACE;
 209         wth->snapshot_length = 0; /* not known */
 210         wth->subtype_read = dct3trace_read;
 211         wth->subtype_seek_read = dct3trace_seek_read;
 212         wth->tsprecision = WTAP_FILE_TSPREC_SEC;
 213
 214         return 1;
 215 }
 216
 217
 218 static gboolean dct3trace_get_packet(FILE_T fh, union wtap_pseudo_header *pseudo_header,
 219         unsigned char *buf, int *len, int *err, gchar **err_info)
 220 {
 221         unsigned char line[1024];
 222         gboolean have_data = FALSE;
 223
 224         while (file_gets(line, sizeof(line), fh) != NULL)
 225         {
 226                 if( memcmp(dct3trace_magic_end, line, strlen(dct3trace_magic_end)) == 0 )
 227                 {
 228                         /* Return on end of file </dump> */
 229                         *err = 0;
 230                         return FALSE;
 231                 }
 232                 else if( memcmp(dct3trace_magic_record_end, line, strlen(dct3trace_magic_record_end)) == 0 )
 233                 {
 234                         /* Return on end of record </l1> */
 235                         if( have_data )
 236                         {
 237                                 *err = 0;
 238                                 return TRUE;
 239                         }
 240                         else
 241                         {
 242                                 /* If not got any data return error */
 243                                 *err = WTAP_ERR_BAD_RECORD;
 244                                 *err_info = g_strdup_printf("dct3trace: record without data");
 245                                 return FALSE;
 246                         }
 247                 }
 248                 else if( memcmp(dct3trace_magic_record_start, line, strlen(dct3trace_magic_record_start)) == 0 )
 249                 {
 250                         /* Parse L1 header <l1 ...>*/
 251                         int channel, tmp, ret = 0;
 252                         char *ptr;
 253
 254                         pseudo_header->gsm_um.uplink = !strstr(line, "direction=\"down\"");
 255                         ret |= xml_get_int(&channel, line, "logicalchannel");
 256
 257                         /* Parse downlink only fields */
 258                         if( !pseudo_header->gsm_um.uplink )
 259                         {
 260                                 ret |= xml_get_int(&tmp, line, "physicalchannel");
 261                                 pseudo_header->gsm_um.arfcn = tmp;
 262                                 ret |= xml_get_int(&tmp, line, "sequence");
 263                                 pseudo_header->gsm_um.tdma_frame = tmp;
 264                                 ret |= xml_get_int(&tmp, line, "bsic");
 265                                 pseudo_header->gsm_um.bsic = tmp;
 266                                 ret |= xml_get_int(&tmp, line, "error");
 267                                 pseudo_header->gsm_um.error = tmp;
 268                                 ret |= xml_get_int(&tmp, line, "timeshift");
 269                                 pseudo_header->gsm_um.timeshift = tmp;
 270                         }
 271
 272                         if( ret != 0 )
 273                         {
 274                                 *err = WTAP_ERR_BAD_RECORD;
 275                                 *err_info = g_strdup_printf("dct3trace: record missing mandatory attributes");
 276                                 return FALSE;
 277                         }
 278
 279                         switch( channel )
 280                         {
 281                                 case 128: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_SDCCH; break;
 282                                 case 112: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_SACCH; break;
 283                                 case 176: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_FACCH; break;
 284                                 case 96: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_CCCH; break;
 285                                 case 80: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_BCCH; break;
 286                                 default: pseudo_header->gsm_um.channel = GSM_UM_CHANNEL_UNKNOWN; break;
 287                         }
 288
 289                         /* Read data (if have it) into buf */
 290                         ptr = strstr(line, "data=\"");
 291                         if( ptr )
 292                         {
 293                                 have_data = TRUE; /* If has data... */
 294                                 *len = hex2bin(buf, ptr+6);
 295                         }
 296                 }
 297                 else if( !have_data && memcmp(dct3trace_magic_l2_start, line, strlen(dct3trace_magic_l2_start)) == 0 )
 298                 {
 299                         /* For uplink packets we might not get the raw L1, so have to recreate it from the L2 */
 300                         /* Parse L2 header if didn't get data from L1 <l2 ...> */
 301                         int data_len = 0;
 302                         char *ptr = strstr(line, "data=\"");
 303
 304                         if( !ptr )
 305                         {
 306                                 continue;
 307                         }
 308
 309                         have_data = TRUE;
 310
 311                         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 )
 312                         {
 313                                 /* Add LAPDm B header */
 314                                 memset(buf, 0x1, 2);
 315                                 *len = 3;
 316                         }
 317                         else
 318                         {
 319                                 /* Add LAPDm Bbis header */
 320                                 *len = 1;
 321                         }
 322                         buf += *len;
 323
 324                         data_len = hex2bin(buf, ptr+6);
 325                         *len += data_len;
 326
 327                         /* Add LAPDm length byte */
 328                         *(buf - 1) = data_len << 2 | 0x1;
 329                 }
 330         }
 331
 332         *err = file_error(fh, err_info);
 333         if (*err == 0)
 334         {
 335                 *err = WTAP_ERR_SHORT_READ;
 336         }
 337         return FALSE;
 338 }
 339
 340
 341 /* Find the next packet and parse it; called from wtap_read(). */
 342 static gboolean dct3trace_read(wtap *wth, int *err, gchar **err_info,
 343     gint64 *data_offset)
 344 {
 345         guint64 offset = file_tell(wth->fh);
 346         int buf_len;
 347         unsigned char buf[MAX_PACKET_LEN];
 348
 349         if( !dct3trace_get_packet(wth->fh, &wth->pseudo_header, buf, &buf_len, err, err_info) )
 350         {
 351                 return FALSE;
 352         }
 353
 354         /* We've got a full packet! */
 355         wth->phdr.ts.secs = 0;
 356         wth->phdr.ts.nsecs = 0;
 357         wth->phdr.caplen = buf_len;
 358         wth->phdr.len = buf_len;
 359
 360         /* Make sure we have enough room for the packet */
 361         buffer_assure_space(wth->frame_buffer, buf_len);
 362         memcpy( buffer_start_ptr(wth->frame_buffer), buf, buf_len );
 363
 364         wth->data_offset = *data_offset = offset;
 365
 366         return TRUE;
 367 }
 368
 369
 370 /* Used to read packets in random-access fashion */
 371 static gboolean dct3trace_seek_read (wtap *wth, gint64 seek_off,
 372         union wtap_pseudo_header *pseudo_header, guint8 *pd, int len,
 373         int *err, gchar **err_info)
 374 {
 375         int buf_len;
 376         unsigned char buf[MAX_PACKET_LEN];
 377
 378         if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
 379         {
 380                 return FALSE;
 381         }
 382
 383         if( !dct3trace_get_packet(wth->random_fh, pseudo_header, buf, &buf_len, err, err_info) )
 384         {
 385                 return FALSE;
 386         }
 387
 388         if( len != buf_len && len != -1 )
 389         {
 390                 *err = WTAP_ERR_BAD_RECORD;
 391                 *err_info = g_strdup_printf("dct3trace: requested length %d doesn't match record length %d",
 392                     len, buf_len);
 393                 return FALSE;
 394         }
 395
 396         if( buf_len > MAX_PACKET_LEN)
 397         {
 398                 *err = WTAP_ERR_BAD_RECORD;
 399                 *err_info = g_strdup_printf("dct3trace: record length %d too long", buf_len);
 400                 return FALSE;
 401         }
 402
 403         memcpy( pd, buf, buf_len );
 404         return TRUE;
 405 }