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  * Wiretap Library
  10  * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 #include "config.h"
  28 #include "wtap-int.h"
  29 #include "dct3trace.h"
  30 #include "file_wrappers.h"
  31
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <errno.h>
  35
  36 #include <wsutil/strtoi.h>
  37
  38 /*
  39    Example downlink data:
  40
  41 <?xml version="1.0"?>
  42 <dump>
  43 <l1 direction="down" logicalchannel="96" physicalchannel="19" sequence="268116" error="0" timeshift="2992" bsic="22" data="31063F100DD0297A53E1020103C802398E0B2B2B2B2B2B" >
  44 <l2 data="063F100DD0297A53E1020103" rest="C802398E0B2B2B2B2B2B" >
  45 </l2>
  46 </l1>
  47 </dump>
  48
  49    Example uplink data (no raw L1):
  50
  51 <?xml version="1.0"?>
  52 <dump>
  53 <l1 direction="up" logicalchannel="112" >
  54 <l2 type="U" subtype="Unknown" p="0" data="061500400000000000000000000000000000" >
  55 </l2>
  56 </l1>
  57 </dump>
  58
  59  */
  60
  61
  62 /* Magic text to check */
  63 static const char dct3trace_magic_line1[] = "<?xml version=\"1.0\"?>";
  64 static const char dct3trace_magic_line2[] = "<dump>";
  65 static const char dct3trace_magic_record_start[]  = "<l1 ";
  66 static const char dct3trace_magic_record_end[]  = "</l1>";
  67 static const char dct3trace_magic_l2_start[]  = "<l2 ";
  68 #if 0 /* Not used ?? */
  69 static const char dct3trace_magic_l2_end[]  = "</l2>";
  70 #endif
  71 static const char dct3trace_magic_end[]  = "</dump>";
  72
  73 #define MAX_PACKET_LEN 23
  74
  75 static gboolean dct3trace_read(wtap *wth, int *err, gchar **err_info,
  76         gint64 *data_offset);
  77 static gboolean dct3trace_seek_read(wtap *wth, gint64 seek_off,
  78         struct wtap_pkthdr *phdr, Buffer *buf, int *err, gchar **err_info);
  79
  80 /*
  81  * Following 3 functions taken from gsmdecode-0.7bis, with permission - http://wiki.thc.org/gsm
  82  */
  83
  84 static int
  85 hc2b(unsigned char hex)
  86 {
  87         hex = g_ascii_tolower(hex);
  88         if ((hex >= '0') && (hex <= '9'))
  89                 return hex - '0';
  90         if ((hex >= 'a') && (hex <= 'f'))
  91                 return hex - 'a' + 10;
  92         return -1;
  93 }
  94
  95 static int
  96 hex2bin(guint8 *out, guint8 *out_end, char *in)
  97 {
  98         guint8 *out_start = out;
  99         int is_low = 0;
 100         int c;
 101
 102         while (*in != '\0')
 103         {
 104                 c = hc2b(*(unsigned char *)in);
 105                 if (c < 0)
 106                 {
 107                         in++;
 108                         continue;
 109                 }
 110                 if (out == out_end)
 111                 {
 112                         /* Too much data */
 113                         return -1;
 114                 }
 115                 if (is_low == 0)
 116                 {
 117                         *out = c << 4;
 118                         is_low = 1;
 119                 } else {
 120                         *out |= (c & 0x0f);
 121                         is_low = 0;
 122                         out++;
 123                 }
 124                 in++;
 125         }
 126
 127         return (int)(out - out_start);
 128 }
 129
 130 static gboolean
 131 xml_get_int(int *val, const char *str, const char *pattern, int *err, gchar **err_info)
 132 {
 133         const char *ptr, *endptr;
 134         char *start, *end;
 135         char buf[32];
 136
 137         ptr = strstr(str, pattern);
 138         if (ptr == NULL) {
 139                 *err = WTAP_ERR_BAD_FILE;
 140                 *err_info = g_strdup_printf("dct3trace: %s not found", pattern);
 141                 return FALSE;
 142         }
 143         /*
 144          * XXX - should we just skip past the pattern and check for ="?
 145          */
 146         start = strchr(ptr, '"');
 147         if (start == NULL) {
 148                 *err = WTAP_ERR_BAD_FILE;
 149                 *err_info = g_strdup_printf("dct3trace: opening quote for %s not found", pattern);
 150                 return FALSE;
 151         }
 152         start++;
 153         /*
 154          * XXX - should we just use ws_strtoi32() and check whether
 155          * the character following the number is a "?
 156          */
 157         end = strchr(start, '"');
 158         if (end == NULL) {
 159                 *err = WTAP_ERR_BAD_FILE;
 160                 *err_info = g_strdup_printf("dct3trace: closing quote for %s not found", pattern);
 161                 return FALSE;
 162         }
 163         if (end - start > 31) {
 164                 *err = WTAP_ERR_BAD_FILE;
 165                 *err_info = g_strdup_printf("dct3trace: %s value is too long", pattern);
 166                 return FALSE;
 167         }
 168
 169         memcpy(buf, start, end - start);
 170         buf[end - start] = '\0';
 171         /*
 172          * XXX - should we allow negative numbers in all cases?  Or are
 173          * there cases where the number is unsigned?
 174          */
 175         if (!ws_strtoi32(buf, &endptr, val)) {
 176                 *err = WTAP_ERR_BAD_FILE;
 177                 if (errno == ERANGE) {
 178                         if (*val < 0)
 179                                 *err_info = g_strdup_printf("dct3trace: %s value is too small, minimum is %d", pattern, *val);
 180                         else
 181                                 *err_info = g_strdup_printf("dct3trace: %s value is too large, maximum is %d", pattern, *val);
 182                 } else
 183                         *err_info = g_strdup_printf("dct3trace: %s value \"%s\" not a number", pattern, buf);
 184                 return FALSE;
 185         }
 186         if (*endptr != '\0') {
 187                 *err = WTAP_ERR_BAD_FILE;
 188                 *err_info = g_strdup_printf("dct3trace: %s value \"%s\" not a number", pattern, buf);
 189                 return FALSE;
 190         }
 191         return TRUE;
 192 }
 193
 194
 195 wtap_open_return_val dct3trace_open(wtap *wth, int *err, gchar **err_info)
 196 {
 197         char line1[64], line2[64];
 198
 199         /* Look for Gammu DCT3 trace header */
 200         if (file_gets(line1, sizeof(line1), wth->fh) == NULL ||
 201                 file_gets(line2, sizeof(line2), wth->fh) == NULL)
 202         {
 203                 *err = file_error(wth->fh, err_info);
 204                 if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
 205                         return WTAP_OPEN_ERROR;
 206                 return WTAP_OPEN_NOT_MINE;
 207         }
 208
 209         /* Don't compare line endings */
 210         if( strncmp(dct3trace_magic_line1, line1, strlen(dct3trace_magic_line1)) != 0 ||
 211                 strncmp(dct3trace_magic_line2, line2, strlen(dct3trace_magic_line2)) != 0)
 212         {
 213                 return WTAP_OPEN_NOT_MINE;
 214         }
 215
 216         wth->file_encap = WTAP_ENCAP_GSM_UM;
 217         wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_DCT3TRACE;
 218         wth->snapshot_length = 0; /* not known */
 219         wth->subtype_read = dct3trace_read;
 220         wth->subtype_seek_read = dct3trace_seek_read;
 221         wth->file_tsprec = WTAP_TSPREC_SEC;
 222
 223         return WTAP_OPEN_MINE;
 224 }
 225
 226
 227 static gboolean dct3trace_get_packet(FILE_T fh, struct wtap_pkthdr *phdr,
 228         Buffer *buf, int *err, gchar **err_info)
 229 {
 230         char line[1024];
 231         guint8 databuf[MAX_PACKET_LEN], *bufp;
 232         gboolean have_data = FALSE;
 233         int len = 0;
 234
 235         bufp = &databuf[0];
 236         while (file_gets(line, sizeof(line), fh) != NULL)
 237         {
 238                 if( memcmp(dct3trace_magic_end, line, strlen(dct3trace_magic_end)) == 0 )
 239                 {
 240                         /* Return on end of file </dump> */
 241                         *err = 0;
 242                         return FALSE;
 243                 }
 244                 else if( memcmp(dct3trace_magic_record_end, line, strlen(dct3trace_magic_record_end)) == 0 )
 245                 {
 246                         /* Return on end of record </l1> */
 247                         if( have_data )
 248                         {
 249                                 /* We've got a full packet! */
 250                                 phdr->rec_type = REC_TYPE_PACKET;
 251                                 phdr->presence_flags = 0; /* no time stamp, no separate "on the wire" length */
 252                                 phdr->ts.secs = 0;
 253                                 phdr->ts.nsecs = 0;
 254                                 phdr->caplen = len;
 255                                 phdr->len = len;
 256
 257                                 *err = 0;
 258
 259                                 /* Make sure we have enough room for the packet */
 260                                 ws_buffer_assure_space(buf, phdr->caplen);
 261                                 memcpy( ws_buffer_start_ptr(buf), databuf, phdr->caplen );
 262
 263                                 return TRUE;
 264                         }
 265                         else
 266                         {
 267                                 /* If not got any data return error */
 268                                 *err = WTAP_ERR_BAD_FILE;
 269                                 *err_info = g_strdup("dct3trace: record without data");
 270                                 return FALSE;
 271                         }
 272                 }
 273                 else if( memcmp(dct3trace_magic_record_start, line, strlen(dct3trace_magic_record_start)) == 0 )
 274                 {
 275                         /* Parse L1 header <l1 ...>*/
 276                         int channel, tmp;
 277                         char *ptr;
 278
 279                         phdr->pseudo_header.gsm_um.uplink = !strstr(line, "direction=\"down\"");
 280                         if (!xml_get_int(&channel, line, "logicalchannel", err, err_info))
 281                                 return FALSE;
 282
 283                         /* Parse downlink only fields */
 284                         if( !phdr->pseudo_header.gsm_um.uplink )
 285                         {
 286                                 if (!xml_get_int(&tmp, line, "physicalchannel", err, err_info))
 287                                         return FALSE;
 288                                 phdr->pseudo_header.gsm_um.arfcn = tmp;
 289                                 if (!xml_get_int(&tmp, line, "sequence", err, err_info))
 290                                         return FALSE;
 291                                 phdr->pseudo_header.gsm_um.tdma_frame = tmp;
 292                                 if (!xml_get_int(&tmp, line, "bsic", err, err_info))
 293                                         return FALSE;
 294                                 phdr->pseudo_header.gsm_um.bsic = tmp;
 295                                 if (!xml_get_int(&tmp, line, "error", err, err_info))
 296                                         return FALSE;
 297                                 phdr->pseudo_header.gsm_um.error = tmp;
 298                                 if (!xml_get_int(&tmp, line, "timeshift", err, err_info))
 299                                         return FALSE;
 300                                 phdr->pseudo_header.gsm_um.timeshift = tmp;
 301                         }
 302
 303                         switch( channel )
 304                         {
 305                                 case 128: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_SDCCH; break;
 306                                 case 112: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_SACCH; break;
 307                                 case 176: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_FACCH; break;
 308                                 case 96: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_CCCH; break;
 309                                 case 80: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_BCCH; break;
 310                                 default: phdr->pseudo_header.gsm_um.channel = GSM_UM_CHANNEL_UNKNOWN; break;
 311                         }
 312
 313                         /* Read data (if have it) into databuf */
 314                         ptr = strstr(line, "data=\"");
 315                         if( ptr )
 316                         {
 317                                 have_data = TRUE; /* If has data... */
 318                                 len = hex2bin(bufp, &databuf[MAX_PACKET_LEN], ptr+6);
 319                                 if (len == -1)
 320                                 {
 321                                         *err = WTAP_ERR_BAD_FILE;
 322                                         *err_info = g_strdup_printf("dct3trace: record length %d too long", phdr->caplen);
 323                                         return FALSE;
 324                                 }
 325                         }
 326                 }
 327                 else if( !have_data && memcmp(dct3trace_magic_l2_start, line, strlen(dct3trace_magic_l2_start)) == 0 )
 328                 {
 329                         /* For uplink packets we might not get the raw L1, so have to recreate it from the L2 */
 330                         /* Parse L2 header if didn't get data from L1 <l2 ...> */
 331                         int data_len;
 332                         char *ptr = strstr(line, "data=\"");
 333
 334                         if( !ptr )
 335                         {
 336                                 continue;
 337                         }
 338
 339                         have_data = TRUE;
 340
 341                         /*
 342                          * We know we have no data already, so we know
 343                          * we have enough room for the header.
 344                          */
 345                         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 )
 346                         {
 347                                 /* Add LAPDm B header */
 348                                 memset(bufp, 0x1, 2);
 349                                 len = 3;
 350                         }
 351                         else
 352                         {
 353                                 /* Add LAPDm Bbis header */
 354                                 len = 1;
 355                         }
 356                         bufp += len;
 357
 358                         data_len = hex2bin(bufp, &databuf[MAX_PACKET_LEN], ptr+6);
 359                         if (data_len == -1)
 360                         {
 361                                 *err = WTAP_ERR_BAD_FILE;
 362                                 *err_info = g_strdup_printf("dct3trace: record length %d too long", phdr->caplen);
 363                                 return FALSE;
 364                         }
 365                         len += data_len;
 366
 367                         /* Add LAPDm length byte */
 368                         *(bufp - 1) = data_len << 2 | 0x1;
 369                 }
 370         }
 371
 372         *err = file_error(fh, err_info);
 373         if (*err == 0)
 374         {
 375                 *err = WTAP_ERR_SHORT_READ;
 376         }
 377         return FALSE;
 378 }
 379
 380
 381 /* Find the next packet and parse it; called from wtap_read(). */
 382 static gboolean dct3trace_read(wtap *wth, int *err, gchar **err_info,
 383     gint64 *data_offset)
 384 {
 385         *data_offset = file_tell(wth->fh);
 386
 387         return dct3trace_get_packet(wth->fh, &wth->phdr, wth->frame_buffer,
 388             err, err_info);
 389 }
 390
 391
 392 /* Used to read packets in random-access fashion */
 393 static gboolean dct3trace_seek_read(wtap *wth, gint64 seek_off,
 394         struct wtap_pkthdr *phdr, Buffer *buf, int *err, gchar **err_info)
 395 {
 396         if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
 397         {
 398                 return FALSE;
 399         }
 400
 401         return dct3trace_get_packet(wth->random_fh, phdr, buf, err, err_info);
 402 }
 403
 404 /*
 405  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 406  *
 407  * Local variables:
 408  * c-basic-offset: 8
 409  * tab-width: 8
 410  * indent-tabs-mode: t
 411  * End:
 412  *
 413  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 414  * :indentSize=8:tabSize=8:noTabs=false:
 415  */