Adding upstream version 4.2.2.upstream/4.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 670 insertions, 0 deletions

diff --git a/wiretap/dbs-etherwatch.c b/wiretap/dbs-etherwatch.c
new file mode 100644
index 00000000..4147b039
--- /dev/null
+++ b/wiretap/dbs-etherwatch.c
@@ -0,0 +1,670 @@
+/* dbs-etherwatch.c
+ *
+ * Wiretap Library
+ * Copyright (c) 2001 by Marc Milgram <ethereal@mmilgram.NOSPAMmail.net>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+#include "wtap-int.h"
+#include "dbs-etherwatch.h"
+#include "file_wrappers.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+/* This module reads the text output of the 'DBS-ETHERTRACE' command in VMS
+ * It was initially based on vms.c.
+ */
+
+/*
+   Example 'ETHERWATCH' output data (with "printable" characters in the
+   "printable characters" section of the output replaced by "." if they have
+   the 8th bit set, so as not to upset compilers that are expecting text
+   in comments to be in a particular character encoding that can't handle
+   those values):
+ETHERWATCH  X5-008
+42 names and addresses were loaded
+Reading recorded data from PERSISTENCE
+------------------------------------------------------------------------------
+From 00-D0-C0-D2-4D-60 [MF1] to AA-00-04-00-FC-94 [PSERVB]
+Protocol 08-00 00 00-00-00-00-00,   60 byte buffer at 10-OCT-2001 10:20:45.16
+  [E..<8...........]-    0-[45 00 00 3C 38 93 00 00 1D 06 D2 12 80 93 11 1A]
+  [.........(......]-   16-[80 93 80 D6 02 D2 02 03 00 28 A4 90 00 00 00 00]
+  [................]-   32-[A0 02 FF FF 95 BD 00 00 02 04 05 B4 03 03 04 01]
+  [............    ]-   48-[01 01 08 0A 90 90 E5 14 00 00 00 00]
+------------------------------------------------------------------------------
+From 00-D0-C0-D2-4D-60 [MF1] to AA-00-04-00-FC-94 [PSERVB]
+Protocol 08-00 00 00-00-00-00-00,   50 byte buffer at 10-OCT-2001 10:20:45.17
+  [E..(8......%....]-    0-[45 00 00 28 38 94 00 00 1D 06 D2 25 80 93 11 1A]
+  [.........(..Z.4w]-   16-[80 93 80 D6 02 D2 02 03 00 28 A4 91 5A 1C 34 77]
+  [P.#(.s..........]-   32-[50 10 23 28 C1 73 00 00 02 04 05 B4 03 03 00 00]
+  [..              ]-   48-[02 04]
+
+
+Alternative HEX only output, slightly more efficient and all wireshark needs:
+------------------------------------------------------------------------------
+From 00-D0-C0-D2-4D-60 [MF1] to AA-00-04-00-FC-94 [PSERVB]
+Protocol 08-00 00 00-00-00-00-00,   50 byte buffer at 10-OCT-2001 10:20:45.17
+     0-[45 00 00 28 38 9B 00 00 1D 06 D2 1E 80 93 11 1A 80 93 80 D6]
+    20-[02 D2 02 03 00 28 A4 BF 5A 1C 34 79 50 10 23 28 C1 43 00 00]
+    40-[03 30 30 30 30 30 00 00 03 30]
+ */
+
+/* Magic text to check for DBS-ETHERWATCH-ness of file */
+static const char dbs_etherwatch_hdr_magic[]  =
+{ 'E', 'T', 'H', 'E', 'R', 'W', 'A', 'T', 'C', 'H', ' '};
+#define DBS_ETHERWATCH_HDR_MAGIC_SIZE  \
+        (sizeof dbs_etherwatch_hdr_magic  / sizeof dbs_etherwatch_hdr_magic[0])
+
+/* Magic text for start of packet */
+static const char dbs_etherwatch_rec_magic[]  =
+{'F', 'r', 'o', 'm', ' '};
+#define DBS_ETHERWATCH_REC_MAGIC_SIZE \
+    (sizeof dbs_etherwatch_rec_magic  / sizeof dbs_etherwatch_rec_magic[0])
+
+/*
+ * Default packet size - maximum normal Ethernet packet size, without an
+ * FCS.
+ */
+#define DBS_ETHERWATCH_MAX_ETHERNET_PACKET_LEN   1514
+
+static gboolean dbs_etherwatch_read(wtap *wth, wtap_rec *rec,
+    Buffer *buf, int *err, gchar **err_info, gint64 *data_offset);
+static gboolean dbs_etherwatch_seek_read(wtap *wth, gint64 seek_off,
+    wtap_rec *rec, Buffer *buf, int *err, gchar **err_info);
+static gboolean parse_dbs_etherwatch_packet(FILE_T fh, wtap_rec *rec,
+    Buffer* buf, int *err, gchar **err_info);
+static guint parse_single_hex_dump_line(char* rec, guint8 *buf,
+    int byte_offset);
+static guint parse_hex_dump(char* dump, guint8 *buf, char separator, char end);
+
+static int dbs_etherwatch_file_type_subtype = -1;
+
+void register_dbs_etherwatch(void);
+
+/* Seeks to the beginning of the next packet, and returns the
+   byte offset.  Returns -1 on failure, and sets "*err" to the error
+   and "*err_info" to null or an additional error string. */
+static gint64 dbs_etherwatch_seek_next_packet(wtap *wth, int *err,
+                                              gchar **err_info)
+{
+    int byte;
+    unsigned int level = 0;
+    gint64 cur_off;
+
+    while ((byte = file_getc(wth->fh)) != EOF) {
+        if (byte == dbs_etherwatch_rec_magic[level]) {
+            level++;
+            if (level >= DBS_ETHERWATCH_REC_MAGIC_SIZE) {
+                /* note: we're leaving file pointer right after the magic characters */
+                cur_off = file_tell(wth->fh);
+                if (cur_off == -1) {
+                    /* Error. */
+                    *err = file_error(wth->fh, err_info);
+                    return -1;
+                }
+                return cur_off + 1;
+            }
+        } else {
+            level = 0;
+        }
+    }
+    /* EOF or error. */
+    *err = file_error(wth->fh, err_info);
+    return -1;
+}
+
+#define DBS_ETHERWATCH_HEADER_LINES_TO_CHECK    200
+#define DBS_ETHERWATCH_LINE_LENGTH      240
+
+/* Look through the first part of a file to see if this is
+ * a DBS Ethertrace text trace file.
+ *
+ * Returns TRUE if it is, FALSE if it isn't or if we get an I/O error;
+ * if we get an I/O error, "*err" will be set to a non-zero value and
+ * "*err_info" will be set to null or an error string.
+ */
+static gboolean dbs_etherwatch_check_file_type(wtap *wth, int *err,
+    gchar **err_info)
+{
+    char    buf[DBS_ETHERWATCH_LINE_LENGTH];
+    int line, byte;
+    gsize   reclen;
+    unsigned int i, level;
+
+    buf[DBS_ETHERWATCH_LINE_LENGTH-1] = 0;
+
+    for (line = 0; line < DBS_ETHERWATCH_HEADER_LINES_TO_CHECK; line++) {
+        if (file_gets(buf, DBS_ETHERWATCH_LINE_LENGTH, wth->fh) == NULL) {
+            /* EOF or error. */
+            *err = file_error(wth->fh, err_info);
+            return FALSE;
+        }
+
+        reclen = strlen(buf);
+        if (reclen < DBS_ETHERWATCH_HDR_MAGIC_SIZE)
+            continue;
+
+        level = 0;
+        for (i = 0; i < reclen; i++) {
+            byte = buf[i];
+            if (byte == dbs_etherwatch_hdr_magic[level]) {
+                level++;
+                if (level >=
+                      DBS_ETHERWATCH_HDR_MAGIC_SIZE) {
+                    return TRUE;
+                }
+            }
+            else
+                level = 0;
+        }
+    }
+    *err = 0;
+    return FALSE;
+}
+
+
+wtap_open_return_val dbs_etherwatch_open(wtap *wth, int *err, gchar **err_info)
+{
+    /* Look for DBS ETHERWATCH header */
+    if (!dbs_etherwatch_check_file_type(wth, err, err_info)) {
+        if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
+            return WTAP_OPEN_ERROR;
+        return WTAP_OPEN_NOT_MINE;
+    }
+
+    wth->file_encap = WTAP_ENCAP_ETHERNET;
+    wth->file_type_subtype = dbs_etherwatch_file_type_subtype;
+    wth->snapshot_length = 0;   /* not known */
+    wth->subtype_read = dbs_etherwatch_read;
+    wth->subtype_seek_read = dbs_etherwatch_seek_read;
+    wth->file_tsprec = WTAP_TSPREC_10_MSEC;
+
+    /*
+     * Add an IDB; we don't know how many interfaces were
+     * involved, so we just say one interface, about which
+     * we only know the link-layer type, snapshot length,
+     * and time stamp resolution.
+     */
+    wtap_add_generated_idb(wth);
+
+    return WTAP_OPEN_MINE;
+}
+
+/* Find the next packet and parse it; called from wtap_read(). */
+static gboolean dbs_etherwatch_read(wtap *wth, wtap_rec *rec,
+    Buffer *buf, int *err, gchar **err_info, gint64 *data_offset)
+{
+    gint64  offset;
+
+    /* Find the next packet */
+    offset = dbs_etherwatch_seek_next_packet(wth, err, err_info);
+    if (offset < 1)
+        return FALSE;
+    *data_offset = offset;
+
+    /* Parse the packet */
+    return parse_dbs_etherwatch_packet(wth->fh, rec, buf, err, err_info);
+}
+
+/* Used to read packets in random-access fashion */
+static gboolean
+dbs_etherwatch_seek_read(wtap *wth, gint64 seek_off,
+    wtap_rec *rec, Buffer *buf, int *err, gchar **err_info)
+{
+    if (file_seek(wth->random_fh, seek_off - 1, SEEK_SET, err) == -1)
+        return FALSE;
+
+    return parse_dbs_etherwatch_packet(wth->random_fh, rec, buf, err,
+        err_info);
+}
+
+/* Parse a packet */
+/*
+Packet header:
+          1         2         3         4
+0123456789012345678901234567890123456789012345
+From 00-D0-C0-D2-4D-60 [MF1] to AA-00-04-00-FC-94 [PSERVB]
+Protocol 08-00 00 00-00-00-00-00,   50 byte buffer at 10-OCT-2001 10:20:45.17
+*/
+#define MAC_ADDR_LENGTH     6           /* Length MAC address */
+#define DEST_MAC_PREFIX     "] to "     /* Prefix to the dest. MAC address */
+#define PROTOCOL_LENGTH     2           /* Length protocol */
+#define PROTOCOL_POS        9           /* Position protocol */
+#define SAP_LENGTH          2           /* Length DSAP+SSAP */
+#define SAP_POS             9           /* Position DSAP+SSAP */
+#define CTL_UNNUMB_LENGTH   1           /* Length unnumbered control field */
+#define CTL_NUMB_LENGTH     2           /* Length numbered control field */
+#define CTL_POS             15          /* Position control field */
+#define PID_LENGTH          5           /* Length PID */
+#define PID_POS             18          /* Position PID */
+#define LENGTH_POS          33          /* Position length */
+#define HEX_HDR_SPR         '-'         /* Separator char header hex values */
+#define HEX_HDR_END         ' '         /* End char hdr. hex val. except PID */
+#define HEX_PID_END         ','         /* End char PID hex value */
+#define IEEE802_LEN_LEN     2           /* Length of the IEEE 802 len. field */
+/*
+To check whether it is Ethernet II or IEEE 802 we check the values of the
+control field and PID, when they are all 0's we assume it is Ethernet II
+else IEEE 802. In IEEE 802 the DSAP and SSAP are behind protocol, the
+length in the IEEE data we have to construct.
+*/
+#define ETH_II_CHECK_POS    15
+#define ETH_II_CHECK_STR    "00 00-00-00-00-00,"
+/*
+To check whether it IEEE 802.3 with SNAP we check that both the DSAP & SSAP
+values are 0xAA and the control field 0x03.
+*/
+#define SNAP_CHECK_POS      9
+#define SNAP_CHECK_STR      "AA-AA 03"
+/*
+To check whether the control field is 1 or two octets we check if it is
+unnumbered. Unnumbered has length 1, numbered 2.
+*/
+#define CTL_UNNUMB_MASK     0x03
+#define CTL_UNNUMB_VALUE    0x03
+static gboolean
+parse_dbs_etherwatch_packet(FILE_T fh, wtap_rec *rec, Buffer* buf,
+    int *err, gchar **err_info)
+{
+    guint8 *pd;
+    char    line[DBS_ETHERWATCH_LINE_LENGTH];
+    int num_items_scanned;
+    int eth_hdr_len, pkt_len, csec;
+    int length_pos, length_from, length;
+    struct tm tm;
+    char mon[4] = "xxx";
+    gchar *p;
+    static const gchar months[] = "JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC";
+    int count, line_count;
+
+    /* Make sure we have enough room for a regular Ethernet packet */
+    ws_buffer_assure_space(buf, DBS_ETHERWATCH_MAX_ETHERNET_PACKET_LEN);
+    pd = ws_buffer_start_ptr(buf);
+
+    eth_hdr_len = 0;
+    memset(&tm, 0, sizeof(tm));
+    /* Our file pointer should be on the first line containing the
+     * summary information for a packet. Read in that line and
+     * extract the useful information
+     */
+    if (file_gets(line, DBS_ETHERWATCH_LINE_LENGTH, fh) == NULL) {
+        *err = file_error(fh, err_info);
+        if (*err == 0) {
+            *err = WTAP_ERR_SHORT_READ;
+        }
+        return FALSE;
+    }
+
+    /* Get the destination address */
+    p = strstr(line, DEST_MAC_PREFIX);
+    if(!p) {
+        *err = WTAP_ERR_BAD_FILE;
+        *err_info = g_strdup("dbs_etherwatch: destination address not found");
+        return FALSE;
+    }
+    p += strlen(DEST_MAC_PREFIX);
+    if(parse_hex_dump(p, &pd[eth_hdr_len], HEX_HDR_SPR, HEX_HDR_END)
+                != MAC_ADDR_LENGTH) {
+        *err = WTAP_ERR_BAD_FILE;
+        *err_info = g_strdup("dbs_etherwatch: destination address not valid");
+        return FALSE;
+    }
+    eth_hdr_len += MAC_ADDR_LENGTH;
+
+    /* Get the source address */
+    /*
+     * Since the first part of the line is already skipped in order to find
+     * the start of the record we cannot index, just look for the first
+     * 'HEX' character
+     */
+    p = line;
+    while(!g_ascii_isxdigit(*p)) {
+        p++;
+    }
+    if(parse_hex_dump(p, &pd[eth_hdr_len], HEX_HDR_SPR,
+        HEX_HDR_END) != MAC_ADDR_LENGTH) {
+        *err = WTAP_ERR_BAD_FILE;
+        *err_info = g_strdup("dbs_etherwatch: source address not valid");
+        return FALSE;
+    }
+    eth_hdr_len += MAC_ADDR_LENGTH;
+
+    /* Read the next line of the record header */
+    if (file_gets(line, DBS_ETHERWATCH_LINE_LENGTH, fh) == NULL) {
+        *err = file_error(fh, err_info);
+        if (*err == 0) {
+            *err = WTAP_ERR_SHORT_READ;
+        }
+        return FALSE;
+    }
+
+    /* Check the lines is as least as long as the length position */
+    if(strlen(line) < LENGTH_POS) {
+        *err = WTAP_ERR_BAD_FILE;
+        *err_info = g_strdup("dbs_etherwatch: line too short");
+        return FALSE;
+    }
+
+    num_items_scanned = sscanf(line + LENGTH_POS,
+                "%9d byte buffer at %2d-%3s-%4d %2d:%2d:%2d.%9d",
+                &pkt_len,
+                &tm.tm_mday, mon,
+                &tm.tm_year, &tm.tm_hour, &tm.tm_min,
+                &tm.tm_sec, &csec);
+
+    if (num_items_scanned != 8) {
+        *err = WTAP_ERR_BAD_FILE;
+        *err_info = g_strdup("dbs_etherwatch: header line not valid");
+        return FALSE;
+    }
+
+    if (pkt_len < 0) {
+        *err = WTAP_ERR_BAD_FILE;
+        *err_info = g_strdup("dbs_etherwatch: packet header has a negative packet length");
+        return FALSE;
+    }
+
+    /* Determine whether it is Ethernet II or IEEE 802 */
+    if(strncmp(&line[ETH_II_CHECK_POS], ETH_II_CHECK_STR,
+        strlen(ETH_II_CHECK_STR)) == 0) {
+        /* Ethernet II */
+        /* Get the Protocol */
+        if(parse_hex_dump(&line[PROTOCOL_POS], &pd[eth_hdr_len], HEX_HDR_SPR,
+                    HEX_HDR_END) != PROTOCOL_LENGTH) {
+            *err = WTAP_ERR_BAD_FILE;
+            *err_info = g_strdup("dbs_etherwatch: Ethernet II protocol value not valid");
+            return FALSE;
+        }
+        eth_hdr_len += PROTOCOL_LENGTH;
+    } else {
+        /* IEEE 802 */
+        /* Remember where to put the length in the header */
+        length_pos = eth_hdr_len;
+        /* Leave room in the header for the length */
+        eth_hdr_len += IEEE802_LEN_LEN;
+        /* Remember how much of the header should not be added to the length */
+        length_from = eth_hdr_len;
+        /* Get the DSAP + SSAP */
+        if(parse_hex_dump(&line[SAP_POS], &pd[eth_hdr_len], HEX_HDR_SPR,
+                    HEX_HDR_END) != SAP_LENGTH) {
+            *err = WTAP_ERR_BAD_FILE;
+            *err_info = g_strdup("dbs_etherwatch: 802.2 DSAP+SSAP value not valid");
+            return FALSE;
+        }
+        eth_hdr_len += SAP_LENGTH;
+        /* Get the (first part of the) control field */
+        if(parse_hex_dump(&line[CTL_POS], &pd[eth_hdr_len], HEX_HDR_SPR,
+                    HEX_HDR_END) != CTL_UNNUMB_LENGTH) {
+            *err = WTAP_ERR_BAD_FILE;
+            *err_info = g_strdup("dbs_etherwatch: 802.2 control field first part not valid");
+            return FALSE;
+        }
+        /* Determine whether the control is numbered, and thus longer */
+        if((pd[eth_hdr_len] & CTL_UNNUMB_MASK) != CTL_UNNUMB_VALUE) {
+            /* Get the rest of the control field, the first octet in the PID */
+            if(parse_hex_dump(&line[PID_POS],
+                        &pd[eth_hdr_len + CTL_UNNUMB_LENGTH], HEX_HDR_END,
+                        HEX_HDR_SPR) != CTL_NUMB_LENGTH - CTL_UNNUMB_LENGTH) {
+                *err = WTAP_ERR_BAD_FILE;
+                *err_info = g_strdup("dbs_etherwatch: 802.2 control field second part value not valid");
+                return FALSE;
+            }
+            eth_hdr_len += CTL_NUMB_LENGTH;
+        } else {
+            eth_hdr_len += CTL_UNNUMB_LENGTH;
+        }
+        /* Determine whether it is SNAP */
+        if(strncmp(&line[SNAP_CHECK_POS], SNAP_CHECK_STR,
+                strlen(SNAP_CHECK_STR)) == 0) {
+            /* Get the PID */
+            if(parse_hex_dump(&line[PID_POS], &pd[eth_hdr_len], HEX_HDR_SPR,
+                        HEX_PID_END) != PID_LENGTH) {
+                *err = WTAP_ERR_BAD_FILE;
+                *err_info = g_strdup("dbs_etherwatch: 802.2 PID value not valid");
+                return FALSE;
+            }
+            eth_hdr_len += PID_LENGTH;
+        }
+        /* Write the length in the header */
+        length = eth_hdr_len - length_from + pkt_len;
+        pd[length_pos] = (length) >> 8;
+        pd[length_pos+1] = (length) & 0xFF;
+    }
+
+    rec->rec_type = REC_TYPE_PACKET;
+    rec->block = wtap_block_create(WTAP_BLOCK_PACKET);
+    rec->presence_flags = WTAP_HAS_TS|WTAP_HAS_CAP_LEN;
+
+    p = strstr(months, mon);
+    if (p)
+        tm.tm_mon = (int)(p - months) / 3;
+    tm.tm_year -= 1900;
+
+    tm.tm_isdst = -1;
+    rec->ts.secs = mktime(&tm);
+    rec->ts.nsecs = csec * 10000000;
+    rec->rec_header.packet_header.caplen = eth_hdr_len + pkt_len;
+    rec->rec_header.packet_header.len = eth_hdr_len + pkt_len;
+
+    if (rec->rec_header.packet_header.caplen > WTAP_MAX_PACKET_SIZE_STANDARD) {
+        /*
+         * Probably a corrupt capture file; return an error,
+         * so that our caller doesn't blow up trying to allocate
+         * space for an immensely-large packet.
+         */
+        *err = WTAP_ERR_BAD_FILE;
+        *err_info = ws_strdup_printf("dbs_etherwatch: File has %u-byte packet, bigger than maximum of %u",
+                                    rec->rec_header.packet_header.caplen, WTAP_MAX_PACKET_SIZE_STANDARD);
+        return FALSE;
+    }
+
+    /* Make sure we have enough room, even for an oversized Ethernet packet */
+    ws_buffer_assure_space(buf, rec->rec_header.packet_header.caplen);
+    pd = ws_buffer_start_ptr(buf);
+
+    /*
+     * We don't have an FCS in this frame.
+     */
+    rec->rec_header.packet_header.pseudo_header.eth.fcs_len = 0;
+
+    /* Parse the hex dump */
+    count = 0;
+    while (count < pkt_len) {
+        if (file_gets(line, DBS_ETHERWATCH_LINE_LENGTH, fh) == NULL) {
+            *err = file_error(fh, err_info);
+            if (*err == 0) {
+                *err = WTAP_ERR_SHORT_READ;
+            }
+            return FALSE;
+        }
+        if (!(line_count = parse_single_hex_dump_line(line,
+                &pd[eth_hdr_len + count], count))) {
+            *err = WTAP_ERR_BAD_FILE;
+            *err_info = g_strdup("dbs_etherwatch: packet data value not valid");
+            return FALSE;
+        }
+        count += line_count;
+        if (count > pkt_len) {
+            *err = WTAP_ERR_BAD_FILE;
+            *err_info = g_strdup("dbs_etherwatch: packet data value has too many bytes");
+            return FALSE;
+        }
+    }
+    return TRUE;
+}
+
+/* Parse a hex dump line */
+/*
+/DISPLAY=BOTH output:
+
+          1         2         3         4
+0123456789012345678901234567890123456789012345
+  [E..(8...........]-    0-[45 00 00 28 38 9B 00 00 1D 06 D2 1E 80 93 11 1A]
+  [.........(..Z.4y]-   16-[80 93 80 D6 02 D2 02 03 00 28 A4 BF 5A 1C 34 79]
+  [P.#(.C...00000..]-   32-[50 10 23 28 C1 43 00 00 03 30 30 30 30 30 00 00]
+  [.0              ]-   48-[03 30]
+
+/DISPLAY=HEXADECIMAL output:
+
+          1         2         3         4
+0123456789012345678901234567890123456789012345
+     0-[45 00 00 28 38 9B 00 00 1D 06 D2 1E 80 93 11 1A 80 93 80 D6]
+    20-[02 D2 02 03 00 28 A4 BF 5A 1C 34 79 50 10 23 28 C1 43 00 00]
+    40-[03 30 30 30 30 30 00 00 03 30]
+
+*/
+
+#define TYPE_CHECK_POS      2   /* Position to check the type of hex dump */
+#define TYPE_CHECK_BOTH     '[' /* Value at pos. that indicates BOTH type */
+#define COUNT_POS_BOTH      21  /* Count position BOTH type */
+#define COUNT_POS_HEX       1   /* Count position HEX type */
+#define COUNT_SIZE      5   /* Length counter */
+#define HEX_DUMP_START      '[' /* Start char */
+#define HEX_DUMP_SPR        ' ' /* Separator char */
+#define HEX_DUMP_END        ']' /* End char */
+
+/* Take a string representing one line from a hex dump and converts the
+ * text to binary data. We check the printed offset with the offset
+ * we are passed to validate the record. We place the bytes in the buffer
+ * at the specified offset.
+ *
+ * Returns length parsed if a good hex dump, 0 if bad.
+ */
+static guint
+parse_single_hex_dump_line(char* rec, guint8 *buf, int byte_offset) {
+
+    int     pos, i;
+    int     value;
+
+
+    /* Check that the record is as least as long as the check offset */
+    for(i = 0; i < TYPE_CHECK_POS; i++)
+    {
+        if(rec[i] == '\0') {
+            return 0;
+        }
+    }
+    /* determine the format and thus the counter offset and hex dump length */
+    if(rec[TYPE_CHECK_POS] == TYPE_CHECK_BOTH)
+    {
+        pos = COUNT_POS_BOTH;
+    }
+    else
+    {
+        pos = COUNT_POS_HEX;
+    }
+
+    /* Check that the record is as least as long as the start position */
+    while(i < pos)
+    {
+        if(rec[i] == '\0') {
+            return 0;
+        }
+        i++;
+    }
+
+    /* Get the byte_offset directly from the record */
+    value = 0;
+    for(i = 0; i < COUNT_SIZE; i++) {
+        if(!g_ascii_isspace(rec[pos])) {
+            if(g_ascii_isdigit(rec[pos])) {
+                value *= 10;
+                value += rec[pos] - '0';
+            } else {
+                return 0;
+            }
+        }
+        pos++;
+    }
+
+    if (value != byte_offset) {
+        return 0;
+    }
+
+    /* find the start of the hex dump */
+    while(rec[pos] != HEX_DUMP_START) {
+        if(rec[pos] == '\0') {
+            return 0;
+        }
+        pos++;
+    }
+    pos++;
+    return parse_hex_dump(&rec[pos], buf, HEX_DUMP_SPR, HEX_DUMP_END);
+}
+
+/* Parse a hex dump */
+static guint
+parse_hex_dump(char* dump, guint8 *buf, char separator, char end) {
+    int     pos, count;
+
+    /* Parse the hex dump */
+    pos = 0;
+    count = 0;
+    while(dump[pos] != end) {
+        /* Check the hex value */
+        if(!(g_ascii_isxdigit(dump[pos]) &&
+            g_ascii_isxdigit(dump[pos + 1]))) {
+            return 0;
+        }
+        /* Get the hex value */
+        if(g_ascii_isdigit(dump[pos])) {
+            buf[count] = (dump[pos] - '0') << 4;
+        } else {
+            buf[count] = (g_ascii_toupper(dump[pos]) - 'A' + 10) << 4;
+        }
+        pos++;
+        if(g_ascii_isdigit(dump[pos])) {
+            buf[count] += dump[pos] - '0';
+        } else {
+            buf[count] += g_ascii_toupper(dump[pos]) - 'A' + 10;
+        }
+        pos++;
+        count++;
+        /* Skip the separator characters */
+        while(dump[pos] == separator) {
+            pos++;
+        }
+    }
+    return count;
+}
+
+static const struct supported_block_type dbs_etherwatch_blocks_supported[] = {
+    /*
+     * We support packet blocks, with no comments or other options.
+     */
+    { WTAP_BLOCK_PACKET, MULTIPLE_BLOCKS_SUPPORTED, NO_OPTIONS_SUPPORTED }
+};
+
+static const struct file_type_subtype_info dbs_etherwatch_info = {
+    "DBS Etherwatch (VMS)", "etherwatch", "txt", NULL,
+    FALSE, BLOCKS_SUPPORTED(dbs_etherwatch_blocks_supported),
+    NULL, NULL, NULL
+};
+
+void register_dbs_etherwatch(void)
+{
+    dbs_etherwatch_file_type_subtype = wtap_register_file_type_subtype(&dbs_etherwatch_info);
+
+    /*
+     * Register name for backwards compatibility with the
+     * wtap_filetypes table in Lua.
+     */
+    wtap_register_backwards_compatibility_lua_name("DBS_ETHERWATCH",
+                                                   dbs_etherwatch_file_type_subtype);
+}
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 4
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * vi: set shiftwidth=4 tabstop=8 expandtab:
+ * :indentSize=4:tabSize=8:noTabs=true:
+ */