wiretap/dbs-etherwatch.c

   1 /* dbs-etherwatch.c
   2  *
   3  * Wiretap Library
   4  * Copyright (c) 2001 by Marc Milgram <ethereal@mmilgram.NOSPAMmail.net>
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-or-later
   7  */
   8
   9 #include "config.h"
  10 #include "dbs-etherwatch.h"
  11 #include "wtap-int.h"
  12 #include "file_wrappers.h"
  13
  14 #include <stdlib.h>
  15 #include <string.h>
  16
  17 /* This module reads the text output of the 'DBS-ETHERTRACE' command in VMS
  18  * It was initially based on vms.c.
  19  */
  20
  21 /*
  22    Example 'ETHERWATCH' output data (with "printable" characters in the
  23    "printable characters" section of the output replaced by "." if they have
  24    the 8th bit set, so as not to upset compilers that are expecting text
  25    in comments to be in a particular character encoding that can't handle
  26    those values):
  27 ETHERWATCH  X5-008
  28 42 names and addresses were loaded
  29 Reading recorded data from PERSISTENCE
  30 ------------------------------------------------------------------------------
  31 From 00-D0-C0-D2-4D-60 [MF1] to AA-00-04-00-FC-94 [PSERVB]
  32 Protocol 08-00 00 00-00-00-00-00,   60 byte buffer at 10-OCT-2001 10:20:45.16
  33   [E..<8...........]-    0-[45 00 00 3C 38 93 00 00 1D 06 D2 12 80 93 11 1A]
  34   [.........(......]-   16-[80 93 80 D6 02 D2 02 03 00 28 A4 90 00 00 00 00]
  35   [................]-   32-[A0 02 FF FF 95 BD 00 00 02 04 05 B4 03 03 04 01]
  36   [............    ]-   48-[01 01 08 0A 90 90 E5 14 00 00 00 00]
  37 ------------------------------------------------------------------------------
  38 From 00-D0-C0-D2-4D-60 [MF1] to AA-00-04-00-FC-94 [PSERVB]
  39 Protocol 08-00 00 00-00-00-00-00,   50 byte buffer at 10-OCT-2001 10:20:45.17
  40   [E..(8......%....]-    0-[45 00 00 28 38 94 00 00 1D 06 D2 25 80 93 11 1A]
  41   [.........(..Z.4w]-   16-[80 93 80 D6 02 D2 02 03 00 28 A4 91 5A 1C 34 77]
  42   [P.#(.s..........]-   32-[50 10 23 28 C1 73 00 00 02 04 05 B4 03 03 00 00]
  43   [..              ]-   48-[02 04]
  44
  45
  46 Alternative HEX only output, slightly more efficient and all wireshark needs:
  47 ------------------------------------------------------------------------------
  48 From 00-D0-C0-D2-4D-60 [MF1] to AA-00-04-00-FC-94 [PSERVB]
  49 Protocol 08-00 00 00-00-00-00-00,   50 byte buffer at 10-OCT-2001 10:20:45.17
  50      0-[45 00 00 28 38 9B 00 00 1D 06 D2 1E 80 93 11 1A 80 93 80 D6]
  51     20-[02 D2 02 03 00 28 A4 BF 5A 1C 34 79 50 10 23 28 C1 43 00 00]
  52     40-[03 30 30 30 30 30 00 00 03 30]
  53  */
  54
  55 /* Magic text to check for DBS-ETHERWATCH-ness of file */
  56 static const char dbs_etherwatch_hdr_magic[]  =
  57 { 'E', 'T', 'H', 'E', 'R', 'W', 'A', 'T', 'C', 'H', ' '};
  58 #define DBS_ETHERWATCH_HDR_MAGIC_SIZE  \
  59         array_length(dbs_etherwatch_hdr_magic)
  60
  61 /* Magic text for start of packet */
  62 static const char dbs_etherwatch_rec_magic[]  =
  63 {'F', 'r', 'o', 'm', ' '};
  64 #define DBS_ETHERWATCH_REC_MAGIC_SIZE \
  65     array_length(dbs_etherwatch_rec_magic)
  66
  67 /*
  68  * Default packet size - maximum normal Ethernet packet size, without an
  69  * FCS.
  70  */
  71 #define DBS_ETHERWATCH_MAX_ETHERNET_PACKET_LEN   1514
  72
  73 static bool dbs_etherwatch_read(wtap *wth, wtap_rec *rec,
  74     Buffer *buf, int *err, char **err_info, int64_t *data_offset);
  75 static bool dbs_etherwatch_seek_read(wtap *wth, int64_t seek_off,
  76     wtap_rec *rec, Buffer *buf, int *err, char **err_info);
  77 static bool parse_dbs_etherwatch_packet(FILE_T fh, wtap_rec *rec,
  78     Buffer* buf, int *err, char **err_info);
  79 static unsigned parse_single_hex_dump_line(char* rec, uint8_t *buf,
  80     int byte_offset);
  81 static unsigned parse_hex_dump(char* dump, uint8_t *buf, char separator, char end);
  82
  83 static int dbs_etherwatch_file_type_subtype = -1;
  84
  85 void register_dbs_etherwatch(void);
  86
  87 /* Seeks to the beginning of the next packet, and returns the
  88    byte offset.  Returns -1 on failure, and sets "*err" to the error
  89    and "*err_info" to null or an additional error string. */
  90 static int64_t dbs_etherwatch_seek_next_packet(wtap *wth, int *err,
  91                                               char **err_info)
  92 {
  93     int byte;
  94     unsigned int level = 0;
  95     int64_t cur_off;
  96
  97     while ((byte = file_getc(wth->fh)) != EOF) {
  98         if (byte == dbs_etherwatch_rec_magic[level]) {
  99             level++;
 100             if (level >= DBS_ETHERWATCH_REC_MAGIC_SIZE) {
 101                 /* note: we're leaving file pointer right after the magic characters */
 102                 cur_off = file_tell(wth->fh);
 103                 if (cur_off == -1) {
 104                     /* Error. */
 105                     *err = file_error(wth->fh, err_info);
 106                     return -1;
 107                 }
 108                 return cur_off + 1;
 109             }
 110         } else {
 111             level = 0;
 112         }
 113     }
 114     /* EOF or error. */
 115     *err = file_error(wth->fh, err_info);
 116     return -1;
 117 }
 118
 119 #define DBS_ETHERWATCH_HEADER_LINES_TO_CHECK    200
 120 #define DBS_ETHERWATCH_LINE_LENGTH      240
 121
 122 /* Look through the first part of a file to see if this is
 123  * a DBS Ethertrace text trace file.
 124  *
 125  * Returns true if it is, false if it isn't or if we get an I/O error;
 126  * if we get an I/O error, "*err" will be set to a non-zero value and
 127  * "*err_info" will be set to null or an error string.
 128  */
 129 static bool dbs_etherwatch_check_file_type(wtap *wth, int *err,
 130     char **err_info)
 131 {
 132     char    buf[DBS_ETHERWATCH_LINE_LENGTH];
 133     int line, byte;
 134     size_t  reclen;
 135     unsigned int i, level;
 136
 137     buf[DBS_ETHERWATCH_LINE_LENGTH-1] = 0;
 138
 139     for (line = 0; line < DBS_ETHERWATCH_HEADER_LINES_TO_CHECK; line++) {
 140         if (file_gets(buf, DBS_ETHERWATCH_LINE_LENGTH, wth->fh) == NULL) {
 141             /* EOF or error. */
 142             *err = file_error(wth->fh, err_info);
 143             return false;
 144         }
 145
 146         reclen = strlen(buf);
 147         if (reclen < DBS_ETHERWATCH_HDR_MAGIC_SIZE)
 148             continue;
 149
 150         level = 0;
 151         for (i = 0; i < reclen; i++) {
 152             byte = buf[i];
 153             if (byte == dbs_etherwatch_hdr_magic[level]) {
 154                 level++;
 155                 if (level >=
 156                       DBS_ETHERWATCH_HDR_MAGIC_SIZE) {
 157                     return true;
 158                 }
 159             }
 160             else
 161                 level = 0;
 162         }
 163     }
 164     *err = 0;
 165     return false;
 166 }
 167
 168
 169 wtap_open_return_val dbs_etherwatch_open(wtap *wth, int *err, char **err_info)
 170 {
 171     /* Look for DBS ETHERWATCH header */
 172     if (!dbs_etherwatch_check_file_type(wth, err, err_info)) {
 173         if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
 174             return WTAP_OPEN_ERROR;
 175         return WTAP_OPEN_NOT_MINE;
 176     }
 177
 178     wth->file_encap = WTAP_ENCAP_ETHERNET;
 179     wth->file_type_subtype = dbs_etherwatch_file_type_subtype;
 180     wth->snapshot_length = 0;   /* not known */
 181     wth->subtype_read = dbs_etherwatch_read;
 182     wth->subtype_seek_read = dbs_etherwatch_seek_read;
 183     wth->file_tsprec = WTAP_TSPREC_10_MSEC;
 184
 185     /*
 186      * Add an IDB; we don't know how many interfaces were
 187      * involved, so we just say one interface, about which
 188      * we only know the link-layer type, snapshot length,
 189      * and time stamp resolution.
 190      */
 191     wtap_add_generated_idb(wth);
 192
 193     return WTAP_OPEN_MINE;
 194 }
 195
 196 /* Find the next packet and parse it; called from wtap_read(). */
 197 static bool dbs_etherwatch_read(wtap *wth, wtap_rec *rec,
 198     Buffer *buf, int *err, char **err_info, int64_t *data_offset)
 199 {
 200     int64_t offset;
 201
 202     /* Find the next packet */
 203     offset = dbs_etherwatch_seek_next_packet(wth, err, err_info);
 204     if (offset < 1)
 205         return false;
 206     *data_offset = offset;
 207
 208     /* Parse the packet */
 209     return parse_dbs_etherwatch_packet(wth->fh, rec, buf, err, err_info);
 210 }
 211
 212 /* Used to read packets in random-access fashion */
 213 static bool
 214 dbs_etherwatch_seek_read(wtap *wth, int64_t seek_off,
 215     wtap_rec *rec, Buffer *buf, int *err, char **err_info)
 216 {
 217     if (file_seek(wth->random_fh, seek_off - 1, SEEK_SET, err) == -1)
 218         return false;
 219
 220     return parse_dbs_etherwatch_packet(wth->random_fh, rec, buf, err,
 221         err_info);
 222 }
 223
 224 /* Parse a packet */
 225 /*
 226 Packet header:
 227           1         2         3         4
 228 0123456789012345678901234567890123456789012345
 229 From 00-D0-C0-D2-4D-60 [MF1] to AA-00-04-00-FC-94 [PSERVB]
 230 Protocol 08-00 00 00-00-00-00-00,   50 byte buffer at 10-OCT-2001 10:20:45.17
 231 */
 232 #define MAC_ADDR_LENGTH     6           /* Length MAC address */
 233 #define DEST_MAC_PREFIX     "] to "     /* Prefix to the dest. MAC address */
 234 #define PROTOCOL_LENGTH     2           /* Length protocol */
 235 #define PROTOCOL_POS        9           /* Position protocol */
 236 #define SAP_LENGTH          2           /* Length DSAP+SSAP */
 237 #define SAP_POS             9           /* Position DSAP+SSAP */
 238 #define CTL_UNNUMB_LENGTH   1           /* Length unnumbered control field */
 239 #define CTL_NUMB_LENGTH     2           /* Length numbered control field */
 240 #define CTL_POS             15          /* Position control field */
 241 #define PID_LENGTH          5           /* Length PID */
 242 #define PID_POS             18          /* Position PID */
 243 #define LENGTH_POS          33          /* Position length */
 244 #define HEX_HDR_SPR         '-'         /* Separator char header hex values */
 245 #define HEX_HDR_END         ' '         /* End char hdr. hex val. except PID */
 246 #define HEX_PID_END         ','         /* End char PID hex value */
 247 #define IEEE802_LEN_LEN     2           /* Length of the IEEE 802 len. field */
 248 /*
 249 To check whether it is Ethernet II or IEEE 802 we check the values of the
 250 control field and PID, when they are all 0's we assume it is Ethernet II
 251 else IEEE 802. In IEEE 802 the DSAP and SSAP are behind protocol, the
 252 length in the IEEE data we have to construct.
 253 */
 254 #define ETH_II_CHECK_POS    15
 255 #define ETH_II_CHECK_STR    "00 00-00-00-00-00,"
 256 /*
 257 To check whether it IEEE 802.3 with SNAP we check that both the DSAP & SSAP
 258 values are 0xAA and the control field 0x03.
 259 */
 260 #define SNAP_CHECK_POS      9
 261 #define SNAP_CHECK_STR      "AA-AA 03"
 262 /*
 263 To check whether the control field is 1 or two octets we check if it is
 264 unnumbered. Unnumbered has length 1, numbered 2.
 265 */
 266 #define CTL_UNNUMB_MASK     0x03
 267 #define CTL_UNNUMB_VALUE    0x03
 268 static bool
 269 parse_dbs_etherwatch_packet(FILE_T fh, wtap_rec *rec, Buffer* buf,
 270     int *err, char **err_info)
 271 {
 272     uint8_t *pd;
 273     char    line[DBS_ETHERWATCH_LINE_LENGTH];
 274     int num_items_scanned;
 275     int eth_hdr_len, pkt_len, csec;
 276     int length_pos, length_from, length;
 277     struct tm tm;
 278     char mon[4] = "xxx";
 279     char *p;
 280     static const char months[] = "JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC";
 281     int count, line_count;
 282
 283     /* Make sure we have enough room for a regular Ethernet packet */
 284     ws_buffer_assure_space(buf, DBS_ETHERWATCH_MAX_ETHERNET_PACKET_LEN);
 285     pd = ws_buffer_start_ptr(buf);
 286
 287     eth_hdr_len = 0;
 288     memset(&tm, 0, sizeof(tm));
 289     /* Our file pointer should be on the first line containing the
 290      * summary information for a packet. Read in that line and
 291      * extract the useful information
 292      */
 293     if (file_gets(line, DBS_ETHERWATCH_LINE_LENGTH, fh) == NULL) {
 294         *err = file_error(fh, err_info);
 295         if (*err == 0) {
 296             *err = WTAP_ERR_SHORT_READ;
 297         }
 298         return false;
 299     }
 300
 301     /* Get the destination address */
 302     p = strstr(line, DEST_MAC_PREFIX);
 303     if(!p) {
 304         *err = WTAP_ERR_BAD_FILE;
 305         *err_info = g_strdup("dbs_etherwatch: destination address not found");
 306         return false;
 307     }
 308     p += strlen(DEST_MAC_PREFIX);
 309     if(parse_hex_dump(p, &pd[eth_hdr_len], HEX_HDR_SPR, HEX_HDR_END)
 310                 != MAC_ADDR_LENGTH) {
 311         *err = WTAP_ERR_BAD_FILE;
 312         *err_info = g_strdup("dbs_etherwatch: destination address not valid");
 313         return false;
 314     }
 315     eth_hdr_len += MAC_ADDR_LENGTH;
 316
 317     /* Get the source address */
 318     /*
 319      * Since the first part of the line is already skipped in order to find
 320      * the start of the record we cannot index, just look for the first
 321      * 'HEX' character
 322      */
 323     p = line;
 324     while(!g_ascii_isxdigit(*p)) {
 325         p++;
 326     }
 327     if(parse_hex_dump(p, &pd[eth_hdr_len], HEX_HDR_SPR,
 328         HEX_HDR_END) != MAC_ADDR_LENGTH) {
 329         *err = WTAP_ERR_BAD_FILE;
 330         *err_info = g_strdup("dbs_etherwatch: source address not valid");
 331         return false;
 332     }
 333     eth_hdr_len += MAC_ADDR_LENGTH;
 334
 335     /* Read the next line of the record header */
 336     if (file_gets(line, DBS_ETHERWATCH_LINE_LENGTH, fh) == NULL) {
 337         *err = file_error(fh, err_info);
 338         if (*err == 0) {
 339             *err = WTAP_ERR_SHORT_READ;
 340         }
 341         return false;
 342     }
 343
 344     /* Check the lines is as least as long as the length position */
 345     if(strlen(line) < LENGTH_POS) {
 346         *err = WTAP_ERR_BAD_FILE;
 347         *err_info = g_strdup("dbs_etherwatch: line too short");
 348         return false;
 349     }
 350
 351     num_items_scanned = sscanf(line + LENGTH_POS,
 352                 "%9d byte buffer at %2d-%3s-%4d %2d:%2d:%2d.%9d",
 353                 &pkt_len,
 354                 &tm.tm_mday, mon,
 355                 &tm.tm_year, &tm.tm_hour, &tm.tm_min,
 356                 &tm.tm_sec, &csec);
 357
 358     if (num_items_scanned != 8) {
 359         *err = WTAP_ERR_BAD_FILE;
 360         *err_info = g_strdup("dbs_etherwatch: header line not valid");
 361         return false;
 362     }
 363
 364     if (pkt_len < 0) {
 365         *err = WTAP_ERR_BAD_FILE;
 366         *err_info = g_strdup("dbs_etherwatch: packet header has a negative packet length");
 367         return false;
 368     }
 369
 370     /* Determine whether it is Ethernet II or IEEE 802 */
 371     if(strncmp(&line[ETH_II_CHECK_POS], ETH_II_CHECK_STR,
 372         strlen(ETH_II_CHECK_STR)) == 0) {
 373         /* Ethernet II */
 374         /* Get the Protocol */
 375         if(parse_hex_dump(&line[PROTOCOL_POS], &pd[eth_hdr_len], HEX_HDR_SPR,
 376                     HEX_HDR_END) != PROTOCOL_LENGTH) {
 377             *err = WTAP_ERR_BAD_FILE;
 378             *err_info = g_strdup("dbs_etherwatch: Ethernet II protocol value not valid");
 379             return false;
 380         }
 381         eth_hdr_len += PROTOCOL_LENGTH;
 382     } else {
 383         /* IEEE 802 */
 384         /* Remember where to put the length in the header */
 385         length_pos = eth_hdr_len;
 386         /* Leave room in the header for the length */
 387         eth_hdr_len += IEEE802_LEN_LEN;
 388         /* Remember how much of the header should not be added to the length */
 389         length_from = eth_hdr_len;
 390         /* Get the DSAP + SSAP */
 391         if(parse_hex_dump(&line[SAP_POS], &pd[eth_hdr_len], HEX_HDR_SPR,
 392                     HEX_HDR_END) != SAP_LENGTH) {
 393             *err = WTAP_ERR_BAD_FILE;
 394             *err_info = g_strdup("dbs_etherwatch: 802.2 DSAP+SSAP value not valid");
 395             return false;
 396         }
 397         eth_hdr_len += SAP_LENGTH;
 398         /* Get the (first part of the) control field */
 399         if(parse_hex_dump(&line[CTL_POS], &pd[eth_hdr_len], HEX_HDR_SPR,
 400                     HEX_HDR_END) != CTL_UNNUMB_LENGTH) {
 401             *err = WTAP_ERR_BAD_FILE;
 402             *err_info = g_strdup("dbs_etherwatch: 802.2 control field first part not valid");
 403             return false;
 404         }
 405         /* Determine whether the control is numbered, and thus longer */
 406         if((pd[eth_hdr_len] & CTL_UNNUMB_MASK) != CTL_UNNUMB_VALUE) {
 407             /* Get the rest of the control field, the first octet in the PID */
 408             if(parse_hex_dump(&line[PID_POS],
 409                         &pd[eth_hdr_len + CTL_UNNUMB_LENGTH], HEX_HDR_END,
 410                         HEX_HDR_SPR) != CTL_NUMB_LENGTH - CTL_UNNUMB_LENGTH) {
 411                 *err = WTAP_ERR_BAD_FILE;
 412                 *err_info = g_strdup("dbs_etherwatch: 802.2 control field second part value not valid");
 413                 return false;
 414             }
 415             eth_hdr_len += CTL_NUMB_LENGTH;
 416         } else {
 417             eth_hdr_len += CTL_UNNUMB_LENGTH;
 418         }
 419         /* Determine whether it is SNAP */
 420         if(strncmp(&line[SNAP_CHECK_POS], SNAP_CHECK_STR,
 421                 strlen(SNAP_CHECK_STR)) == 0) {
 422             /* Get the PID */
 423             if(parse_hex_dump(&line[PID_POS], &pd[eth_hdr_len], HEX_HDR_SPR,
 424                         HEX_PID_END) != PID_LENGTH) {
 425                 *err = WTAP_ERR_BAD_FILE;
 426                 *err_info = g_strdup("dbs_etherwatch: 802.2 PID value not valid");
 427                 return false;
 428             }
 429             eth_hdr_len += PID_LENGTH;
 430         }
 431         /* Write the length in the header */
 432         length = eth_hdr_len - length_from + pkt_len;
 433         pd[length_pos] = (length) >> 8;
 434         pd[length_pos+1] = (length) & 0xFF;
 435     }
 436
 437     rec->rec_type = REC_TYPE_PACKET;
 438     rec->block = wtap_block_create(WTAP_BLOCK_PACKET);
 439     rec->presence_flags = WTAP_HAS_TS|WTAP_HAS_CAP_LEN;
 440
 441     p = strstr(months, mon);
 442     if (p)
 443         tm.tm_mon = (int)(p - months) / 3;
 444     tm.tm_year -= 1900;
 445
 446     tm.tm_isdst = -1;
 447     rec->ts.secs = mktime(&tm);
 448     rec->ts.nsecs = csec * 10000000;
 449     rec->rec_header.packet_header.caplen = eth_hdr_len + pkt_len;
 450     rec->rec_header.packet_header.len = eth_hdr_len + pkt_len;
 451
 452     if (rec->rec_header.packet_header.caplen > WTAP_MAX_PACKET_SIZE_STANDARD) {
 453         /*
 454          * Probably a corrupt capture file; return an error,
 455          * so that our caller doesn't blow up trying to allocate
 456          * space for an immensely-large packet.
 457          */
 458         *err = WTAP_ERR_BAD_FILE;
 459         *err_info = ws_strdup_printf("dbs_etherwatch: File has %u-byte packet, bigger than maximum of %u",
 460                                     rec->rec_header.packet_header.caplen, WTAP_MAX_PACKET_SIZE_STANDARD);
 461         return false;
 462     }
 463
 464     /* Make sure we have enough room, even for an oversized Ethernet packet */
 465     ws_buffer_assure_space(buf, rec->rec_header.packet_header.caplen);
 466     pd = ws_buffer_start_ptr(buf);
 467
 468     /*
 469      * We don't have an FCS in this frame.
 470      */
 471     rec->rec_header.packet_header.pseudo_header.eth.fcs_len = 0;
 472
 473     /* Parse the hex dump */
 474     count = 0;
 475     while (count < pkt_len) {
 476         if (file_gets(line, DBS_ETHERWATCH_LINE_LENGTH, fh) == NULL) {
 477             *err = file_error(fh, err_info);
 478             if (*err == 0) {
 479                 *err = WTAP_ERR_SHORT_READ;
 480             }
 481             return false;
 482         }
 483         if (!(line_count = parse_single_hex_dump_line(line,
 484                 &pd[eth_hdr_len + count], count))) {
 485             *err = WTAP_ERR_BAD_FILE;
 486             *err_info = g_strdup("dbs_etherwatch: packet data value not valid");
 487             return false;
 488         }
 489         count += line_count;
 490         if (count > pkt_len) {
 491             *err = WTAP_ERR_BAD_FILE;
 492             *err_info = g_strdup("dbs_etherwatch: packet data value has too many bytes");
 493             return false;
 494         }
 495     }
 496     return true;
 497 }
 498
 499 /* Parse a hex dump line */
 500 /*
 501 /DISPLAY=BOTH output:
 502
 503           1         2         3         4
 504 0123456789012345678901234567890123456789012345
 505   [E..(8...........]-    0-[45 00 00 28 38 9B 00 00 1D 06 D2 1E 80 93 11 1A]
 506   [.........(..Z.4y]-   16-[80 93 80 D6 02 D2 02 03 00 28 A4 BF 5A 1C 34 79]
 507   [P.#(.C...00000..]-   32-[50 10 23 28 C1 43 00 00 03 30 30 30 30 30 00 00]
 508   [.0              ]-   48-[03 30]
 509
 510 /DISPLAY=HEXADECIMAL output:
 511
 512           1         2         3         4
 513 0123456789012345678901234567890123456789012345
 514      0-[45 00 00 28 38 9B 00 00 1D 06 D2 1E 80 93 11 1A 80 93 80 D6]
 515     20-[02 D2 02 03 00 28 A4 BF 5A 1C 34 79 50 10 23 28 C1 43 00 00]
 516     40-[03 30 30 30 30 30 00 00 03 30]
 517
 518 */
 519
 520 #define TYPE_CHECK_POS      2   /* Position to check the type of hex dump */
 521 #define TYPE_CHECK_BOTH     '[' /* Value at pos. that indicates BOTH type */
 522 #define COUNT_POS_BOTH      21  /* Count position BOTH type */
 523 #define COUNT_POS_HEX       1   /* Count position HEX type */
 524 #define COUNT_SIZE      5   /* Length counter */
 525 #define HEX_DUMP_START      '[' /* Start char */
 526 #define HEX_DUMP_SPR        ' ' /* Separator char */
 527 #define HEX_DUMP_END        ']' /* End char */
 528
 529 /* Take a string representing one line from a hex dump and converts the
 530  * text to binary data. We check the printed offset with the offset
 531  * we are passed to validate the record. We place the bytes in the buffer
 532  * at the specified offset.
 533  *
 534  * Returns length parsed if a good hex dump, 0 if bad.
 535  */
 536 static unsigned
 537 parse_single_hex_dump_line(char* rec, uint8_t *buf, int byte_offset) {
 538
 539     int     pos, i;
 540     int     value;
 541
 542
 543     /* Check that the record is as least as long as the check offset */
 544     for(i = 0; i < TYPE_CHECK_POS; i++)
 545     {
 546         if(rec[i] == '\0') {
 547             return 0;
 548         }
 549     }
 550     /* determine the format and thus the counter offset and hex dump length */
 551     if(rec[TYPE_CHECK_POS] == TYPE_CHECK_BOTH)
 552     {
 553         pos = COUNT_POS_BOTH;
 554     }
 555     else
 556     {
 557         pos = COUNT_POS_HEX;
 558     }
 559
 560     /* Check that the record is as least as long as the start position */
 561     while(i < pos)
 562     {
 563         if(rec[i] == '\0') {
 564             return 0;
 565         }
 566         i++;
 567     }
 568
 569     /* Get the byte_offset directly from the record */
 570     value = 0;
 571     for(i = 0; i < COUNT_SIZE; i++) {
 572         if(!g_ascii_isspace(rec[pos])) {
 573             if(g_ascii_isdigit(rec[pos])) {
 574                 value *= 10;
 575                 value += rec[pos] - '0';
 576             } else {
 577                 return 0;
 578             }
 579         }
 580         pos++;
 581     }
 582
 583     if (value != byte_offset) {
 584         return 0;
 585     }
 586
 587     /* find the start of the hex dump */
 588     while(rec[pos] != HEX_DUMP_START) {
 589         if(rec[pos] == '\0') {
 590             return 0;
 591         }
 592         pos++;
 593     }
 594     pos++;
 595     return parse_hex_dump(&rec[pos], buf, HEX_DUMP_SPR, HEX_DUMP_END);
 596 }
 597
 598 /* Parse a hex dump */
 599 static unsigned
 600 parse_hex_dump(char* dump, uint8_t *buf, char separator, char end) {
 601     int     pos, count;
 602
 603     /* Parse the hex dump */
 604     pos = 0;
 605     count = 0;
 606     while(dump[pos] != end) {
 607         /* Check the hex value */
 608         if(!(g_ascii_isxdigit(dump[pos]) &&
 609             g_ascii_isxdigit(dump[pos + 1]))) {
 610             return 0;
 611         }
 612         /* Get the hex value */
 613         if(g_ascii_isdigit(dump[pos])) {
 614             buf[count] = (dump[pos] - '0') << 4;
 615         } else {
 616             buf[count] = (g_ascii_toupper(dump[pos]) - 'A' + 10) << 4;
 617         }
 618         pos++;
 619         if(g_ascii_isdigit(dump[pos])) {
 620             buf[count] += dump[pos] - '0';
 621         } else {
 622             buf[count] += g_ascii_toupper(dump[pos]) - 'A' + 10;
 623         }
 624         pos++;
 625         count++;
 626         /* Skip the separator characters */
 627         while(dump[pos] == separator) {
 628             pos++;
 629         }
 630     }
 631     return count;
 632 }
 633
 634 static const struct supported_block_type dbs_etherwatch_blocks_supported[] = {
 635     /*
 636      * We support packet blocks, with no comments or other options.
 637      */
 638     { WTAP_BLOCK_PACKET, MULTIPLE_BLOCKS_SUPPORTED, NO_OPTIONS_SUPPORTED }
 639 };
 640
 641 static const struct file_type_subtype_info dbs_etherwatch_info = {
 642     "DBS Etherwatch (VMS)", "etherwatch", "txt", NULL,
 643     false, BLOCKS_SUPPORTED(dbs_etherwatch_blocks_supported),
 644     NULL, NULL, NULL
 645 };
 646
 647 void register_dbs_etherwatch(void)
 648 {
 649     dbs_etherwatch_file_type_subtype = wtap_register_file_type_subtype(&dbs_etherwatch_info);
 650
 651     /*
 652      * Register name for backwards compatibility with the
 653      * wtap_filetypes table in Lua.
 654      */
 655     wtap_register_backwards_compatibility_lua_name("DBS_ETHERWATCH",
 656                                                    dbs_etherwatch_file_type_subtype);
 657 }
 658
 659 /*
 660  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 661  *
 662  * Local variables:
 663  * c-basic-offset: 4
 664  * tab-width: 8
 665  * indent-tabs-mode: nil
 666  * End:
 667  *
 668  * vi: set shiftwidth=4 tabstop=8 expandtab:
 669  * :indentSize=4:tabSize=8:noTabs=true:
 670  */