wiretap/aethra.c

   1 /* aethra.c
   2  *
   3  * $Id$
   4  *
   5  * Wiretap Library
   6  * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; either version 2
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 #include "config.h"
  24 #include <errno.h>
  25 #include <string.h>
  26 #include "wtap-int.h"
  27 #include "file_wrappers.h"
  28 #include "buffer.h"
  29 #include "aethra.h"
  30
  31 /* Magic number in Aethra PC108 files. */
  32 #define MAGIC_SIZE      5
  33
  34 static const guchar aethra_magic[MAGIC_SIZE] = {
  35         'V', '0', '2', '0', '8'
  36 };
  37
  38 /* Aethra file header. */
  39 struct aethra_hdr {
  40         guchar  magic[MAGIC_SIZE];
  41         guint8  unknown1[39];
  42         guchar  sw_vers[60];    /* software version string, not null-terminated */
  43         guint8  unknown2[118];
  44         guint8  start_sec;      /* seconds of capture start time */
  45         guint8  start_min;      /* minutes of capture start time */
  46         guint8  start_hour;     /* hour of capture start time */
  47         guint8  unknown3[5007];
  48         guint8  start_year[2];  /* year of capture start date */
  49         guint8  start_month[2]; /* month of capture start date */
  50         guint8  unknown4[2];
  51         guint8  start_day[2];   /* day of capture start date */
  52         guint8  unknown5[8];
  53         guchar  com_info[16];   /* COM port and speed, null-padded(?) */
  54         guint8  unknown6[107];
  55         guchar  xxx_vers[41];   /* unknown version string (longer, null-padded?) */
  56 };
  57
  58 /* Aethra record header.  Yes, the alignment is weird.
  59    All multi-byte fields are little-endian. */
  60 struct aethrarec_hdr {
  61         guint8 rec_size[2];     /* record length, not counting the length itself */
  62         guint8 rec_type;        /* record type */
  63         guint8 timestamp[4];    /* milliseconds since start of capture */
  64         guint8 flags;           /* low-order bit: 0 = N->U, 1 = U->N */
  65 };
  66
  67 /*
  68  * Record types.
  69  *
  70  * As the indications from the device and signalling messages appear not
  71  * to have the 8th bit set, and at least some B-channel records do, we
  72  * assume, for now, that the 8th bit indicates bearer information.
  73  *
  74  * 0x9F is the record type seen for B31 channel records; that might be
  75  * 0x80|31, so, for now, we assume that if the 8th bit is set, the B
  76  * channel number is in the low 7 bits.
  77  */
  78 #define AETHRA_BEARER           0x80    /* bearer information */
  79
  80 #define AETHRA_DEVICE           0x00    /* indication from the monitoring device */
  81 #define AETHRA_ISDN_LINK        0x01    /* information from the ISDN link */
  82
  83 /*
  84  * In AETHRA_DEVICE records, the flags field has what appears to
  85  * be a record subtype.
  86  */
  87 #define AETHRA_DEVICE_STOP_MONITOR      0x00    /* Stop Monitor */
  88 #define AETHRA_DEVICE_START_MONITOR     0x04    /* Start Monitor */
  89 #define AETHRA_DEVICE_ACTIVATION        0x05    /* Activation */
  90 #define AETHRA_DEVICE_START_CAPTURE     0x5F    /* Start Capture */
  91
  92 /*
  93  * In AETHRA_ISDN_LINK and bearer channel records, the flags field has
  94  * a direction flag and possibly some other bits.
  95  *
  96  * In AETHRA_ISDN_LINK records, at least some of the other bits are
  97  * a subtype.
  98  *
  99  * In bearer channel records, there are records with data and
 100  * "Constant Value" records with a single byte.  Data has a
 101  * flags value of 0x14 ORed with the direction flag, and Constant Value
 102  * records have a flags value of 0x16 ORed with the direction flag.
 103  * There are also records of an unknown type with 0x02, probably
 104  * ORed with the direction flag.
 105  */
 106 #define AETHRA_U_TO_N                           0x01    /* set for TE->NT */
 107
 108 #define AETHRA_ISDN_LINK_SUBTYPE                0xFE
 109 #define AETHRA_ISDN_LINK_LAPD                   0x00    /* LAPD frame */
 110 #define AETHRA_ISDN_LINK_SA_BITS                0x2E    /* 2048K PRI Sa bits (G.704 section 2.3.2) */
 111 #define AETHRA_ISDN_LINK_ALL_ALARMS_CLEARED     0x30    /* All Alarms Cleared */
 112
 113 typedef struct {
 114         time_t  start;
 115 } aethra_t;
 116
 117 static gboolean aethra_read(wtap *wth, int *err, gchar **err_info,
 118     gint64 *data_offset);
 119 static gboolean aethra_seek_read(wtap *wth, gint64 seek_off,
 120     struct wtap_pkthdr *phdr, Buffer *buf, int length,
 121     int *err, gchar **err_info);
 122 static gboolean aethra_read_rec_header(wtap *wth, FILE_T fh, struct aethrarec_hdr *hdr,
 123     struct wtap_pkthdr *phdr, int *err, gchar **err_info);
 124
 125 int aethra_open(wtap *wth, int *err, gchar **err_info)
 126 {
 127         int bytes_read;
 128         struct aethra_hdr hdr;
 129         struct tm tm;
 130         aethra_t *aethra;
 131
 132         /* Read in the string that should be at the start of a "aethra" file */
 133         errno = WTAP_ERR_CANT_READ;
 134         bytes_read = file_read(hdr.magic, sizeof hdr.magic, wth->fh);
 135         if (bytes_read != sizeof hdr.magic) {
 136                 *err = file_error(wth->fh, err_info);
 137                 if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
 138                         return -1;
 139                 return 0;
 140         }
 141
 142         if (memcmp(hdr.magic, aethra_magic, sizeof aethra_magic) != 0)
 143                 return 0;
 144
 145         /* Read the rest of the header. */
 146         errno = WTAP_ERR_CANT_READ;
 147         bytes_read = file_read((char *)&hdr + sizeof hdr.magic,
 148             sizeof hdr - sizeof hdr.magic, wth->fh);
 149         if (bytes_read != sizeof hdr - sizeof hdr.magic) {
 150                 *err = file_error(wth->fh, err_info);
 151                 if (*err == 0)
 152                         *err = WTAP_ERR_SHORT_READ;
 153                 return -1;
 154         }
 155         wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_AETHRA;
 156         aethra = (aethra_t *)g_malloc(sizeof(aethra_t));
 157         wth->priv = (void *)aethra;
 158         wth->subtype_read = aethra_read;
 159         wth->subtype_seek_read = aethra_seek_read;
 160
 161         /*
 162          * Convert the time stamp to a "time_t".
 163          */
 164         tm.tm_year = pletohs(&hdr.start_year) - 1900;
 165         tm.tm_mon = pletohs(&hdr.start_month) - 1;
 166         tm.tm_mday = pletohs(&hdr.start_day);
 167         tm.tm_hour = hdr.start_hour;
 168         tm.tm_min = hdr.start_min;
 169         tm.tm_sec = hdr.start_sec;
 170         tm.tm_isdst = -1;
 171         aethra->start = mktime(&tm);
 172
 173         /*
 174          * We've only seen ISDN files, so, for now, we treat all
 175          * files as ISDN.
 176          */
 177         wth->file_encap = WTAP_ENCAP_ISDN;
 178         wth->snapshot_length = 0;       /* not available in header */
 179         wth->tsprecision = WTAP_FILE_TSPREC_MSEC;
 180         return 1;
 181 }
 182
 183 #if 0
 184 static guint packet = 0;
 185 #endif
 186
 187 /* Read the next packet */
 188 static gboolean aethra_read(wtap *wth, int *err, gchar **err_info,
 189     gint64 *data_offset)
 190 {
 191         struct aethrarec_hdr hdr;
 192
 193         /*
 194          * Keep reading until we see an AETHRA_ISDN_LINK with a subtype
 195          * of AETHRA_ISDN_LINK_LAPD record or get an end-of-file.
 196          */
 197         for (;;) {
 198                 *data_offset = file_tell(wth->fh);
 199
 200                 /* Read record header. */
 201                 if (!aethra_read_rec_header(wth, wth->fh, &hdr, &wth->phdr, err, err_info))
 202                         return FALSE;
 203
 204                 /*
 205                  * XXX - if this is big, we might waste memory by
 206                  * growing the buffer to handle it.
 207                  */
 208                 if (wth->phdr.caplen != 0) {
 209                         if (!wtap_read_packet_bytes(wth->fh, wth->frame_buffer,
 210                             wth->phdr.caplen, err, err_info))
 211                                 return FALSE;   /* Read error */
 212                 }
 213 #if 0
 214 packet++;
 215 #endif
 216                 switch (hdr.rec_type) {
 217
 218                 case AETHRA_ISDN_LINK:
 219 #if 0
 220 fprintf(stderr, "Packet %u: type 0x%02x (AETHRA_ISDN_LINK)\n",
 221 packet, hdr.rec_type);
 222 #endif
 223                         switch (hdr.flags & AETHRA_ISDN_LINK_SUBTYPE) {
 224
 225                         case AETHRA_ISDN_LINK_LAPD:
 226                                 /*
 227                                  * The data is a LAPD frame.
 228                                  */
 229 #if 0
 230 fprintf(stderr, "    subtype 0x%02x (AETHRA_ISDN_LINK_LAPD)\n", hdr.flags & AETHRA_ISDN_LINK_SUBTYPE);
 231 #endif
 232                                 goto found;
 233
 234                         case AETHRA_ISDN_LINK_SA_BITS:
 235                                 /*
 236                                  * These records have one data byte, which
 237                                  * has the Sa bits in the lower 5 bits.
 238                                  *
 239                                  * XXX - what about stuff other than 2048K
 240                                  * PRI lines?
 241                                  */
 242 #if 0
 243 fprintf(stderr, "    subtype 0x%02x (AETHRA_ISDN_LINK_SA_BITS)\n", hdr.flags & AETHRA_ISDN_LINK_SUBTYPE);
 244 #endif
 245                                 break;
 246
 247                         case AETHRA_ISDN_LINK_ALL_ALARMS_CLEARED:
 248                                 /*
 249                                  * No data, just an "all alarms cleared"
 250                                  * indication.
 251                                  */
 252 #if 0
 253 fprintf(stderr, "    subtype 0x%02x (AETHRA_ISDN_LINK_ALL_ALARMS_CLEARED)\n", hdr.flags & AETHRA_ISDN_LINK_SUBTYPE);
 254 #endif
 255                                 break;
 256
 257                         default:
 258 #if 0
 259 fprintf(stderr, "    subtype 0x%02x, packet_size %u, direction 0x%02x\n",
 260 hdr.flags & AETHRA_ISDN_LINK_SUBTYPE, wth->phdr.caplen, hdr.flags & AETHRA_U_TO_N);
 261 #endif
 262                                 break;
 263                         }
 264                         break;
 265
 266                 default:
 267 #if 0
 268 fprintf(stderr, "Packet %u: type 0x%02x, packet_size %u, flags 0x%02x\n",
 269 packet, hdr.rec_type, wth->phdr.caplen, hdr.flags);
 270 #endif
 271                         break;
 272                 }
 273         }
 274
 275 found:
 276         return TRUE;
 277 }
 278
 279 static gboolean
 280 aethra_seek_read(wtap *wth, gint64 seek_off, struct wtap_pkthdr *phdr,
 281     Buffer *buf, int length, int *err, gchar **err_info)
 282 {
 283         struct aethrarec_hdr hdr;
 284
 285         if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
 286                 return FALSE;
 287
 288         if (!aethra_read_rec_header(wth, wth->random_fh, &hdr, phdr, err, err_info))
 289                 return FALSE;
 290
 291         /*
 292          * Read the packet data.
 293          */
 294         if (!wtap_read_packet_bytes(wth->random_fh, buf, length, err, err_info))
 295                 return FALSE;   /* failed */
 296
 297         return TRUE;
 298 }
 299
 300 static gboolean
 301 aethra_read_rec_header(wtap *wth, FILE_T fh, struct aethrarec_hdr *hdr,
 302     struct wtap_pkthdr *phdr, int *err, gchar **err_info)
 303 {
 304         aethra_t *aethra = (aethra_t *)wth->priv;
 305         int     bytes_read;
 306         guint32 rec_size;
 307         guint32 packet_size;
 308         guint32 msecs;
 309
 310         /* Read record header. */
 311         errno = WTAP_ERR_CANT_READ;
 312         bytes_read = file_read(hdr, sizeof *hdr, fh);
 313         if (bytes_read != sizeof *hdr) {
 314                 *err = file_error(fh, err_info);
 315                 if (*err == 0 && bytes_read != 0)
 316                         *err = WTAP_ERR_SHORT_READ;
 317                 return FALSE;
 318         }
 319
 320         rec_size = pletohs(hdr->rec_size);
 321         if (rec_size < (sizeof *hdr - sizeof hdr->rec_size)) {
 322                 /* The record is shorter than a record header. */
 323                 *err = WTAP_ERR_BAD_FILE;
 324                 *err_info = g_strdup_printf("aethra: File has %u-byte record, less than minimum of %u",
 325                     rec_size,
 326                     (unsigned int)(sizeof *hdr - sizeof hdr->rec_size));
 327                 return FALSE;
 328         }
 329
 330         packet_size = rec_size - (guint32)(sizeof *hdr - sizeof hdr->rec_size);
 331
 332         msecs = pletohl(hdr->timestamp);
 333         phdr->presence_flags = WTAP_HAS_TS;
 334         phdr->ts.secs = aethra->start + (msecs / 1000);
 335         phdr->ts.nsecs = (msecs % 1000) * 1000000;
 336         phdr->caplen = packet_size;
 337         phdr->len = packet_size;
 338         phdr->pseudo_header.isdn.uton = (hdr->flags & AETHRA_U_TO_N);
 339         phdr->pseudo_header.isdn.channel = 0;   /* XXX - D channel */
 340
 341         return TRUE;
 342 }