/* vms.c
 *
 * $Id: vms.c 14006 2005-04-03 11:00:49Z guy $
 *
 * Wiretap Library
 * Copyright (c) 2001 by Marc Milgram <ethereal@mmilgram.NOSPAMmail.net>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

/* Notes:
 *   TCPIPtrace TCP fragments don't have the header line.  So, we are never
 *   to look for that line for the first line of a packet except the first
 *   packet.  This allows us to read fragmented packets.  Define
 *   TCPIPTRACE_FRAGMENTS_HAVE_HEADER_LINE to expect the first line to be
 *   at the start of every packet.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "wtap-int.h"
#include "buffer.h"
#include "vms.h"
#include "file_wrappers.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

/* This module reads the output of the various VMS TCPIP trace utilities
 * such as TCPIPTRACE, TCPTRACE and UCX$TRACE
 *
 * It was initially based on toshiba.c and refined with code from cosine.c

--------------------------------------------------------------------------------
   Example TCPIPTRACE TCPTRACE output data:

   TCPIPtrace full display RCV packet 8 at 10-JUL-2001 14:54:19.56

   IP Version = 4,  IHL = 5,  TOS = 00,   Total Length = 84 = ^x0054
   IP Identifier  = ^x178F,  Flags (0=0,DF=0,MF=0),
         Fragment Offset = 0 = ^x0000,   Calculated Offset = 0 = ^x0000
   IP TTL = 64 = ^x40,  Protocol = 17 = ^x11,  Header Checksum = ^x4C71
   IP Source Address      = 10.12.1.80
   IP Destination Address = 10.12.1.50

   UDP Source Port = 731,   UDP Destination Port = 111
   UDP Header and Datagram Length = 64 = ^x0040,   Checksum = ^xB6C0

   50010C0A   714C1140   00008F17   54000045    0000    E..T....@.Lq...P
   27E54C3C | C0B64000   6F00DB02 | 32010C0A    0010    ...2...o.@..<L.'
   02000000   A0860100   02000000   00000000    0020    ................
   00000000   00000000   00000000   03000000    0030    ................
   06000000   01000000   A5860100   00000000    0040    ................
                                    00000000    0050    ....
--------------------------------------------------------------------------------

   Example UCX$TRACE output data:

    UCX INTERnet trace RCV packet seq # = 1 at 14-MAY-2003 11:32:10.93 

   IP Version = 4,  IHL = 5,  TOS = 00,   Total Length = 583 = ^x0247 
   IP Identifier  = ^x702E,  Flags (0=0,DF=0,MF=0),  
         Fragment Offset = 0 = ^x0000,   Calculated Offset = 0 = ^x0000 
   IP TTL = 128 = ^x80,  Protocol = 17 = ^x11,  Header Checksum = ^x70EC 
   IP Source Address      = 10.20.4.159 
   IP Destination Address = 10.20.4.255 

   UDP Source Port = 138,   UDP Destination Port = 138 
   UDP Header and Datagram Length = 563 = ^x0233,   Checksum = ^xB913 

   9F04140A   70EC1180   0000702E   47020045    0000    E..G.p.....p....
   B1B80E11 | B9133302   8A008A00 | FF04140A    0010    .........3......
   46484648   45200000   1D028A00   9F04140A    0020    ...........EHFHF
   43414341   4341434D   454D4546   45454550    0030    PEEEFEMEMCACACAC

--------------------------------------------------------------------------------

   Alternate UCX$TRACE type output data:

   TCPIP INTERnet trace RCV packet seq # = 1 at 23-OCT-1998 15:19:33.29

   IP Version = 4,  IHL = 5,  TOS = 00,   Total Length = 217 = ^x00D9
   IP Identifier  = ^x0065,  Flags (0=0,DF=0,MF=0),
         Fragment Offset = 0 = ^x0000,   Calculated Offset = 0 = ^x0000
   IP TTL = 32 = ^x20,  Protocol = 17 = ^x11,  Header Checksum = ^x8F6C
   IP Source Address      = 16.20.168.93
   IP Destination Address = 16.20.255.255

   UDP Source Port = 138,   UDP Destination Port = 138
   UDP Header and Datagram Length = 197 = ^x00C5,   Checksum = ^x0E77

   5DA81410   8F6C1120   00000065   D9000045    0000    E...awe.....l....]
            | 0E77C500   8A008A00 | FFFF1410    0010    ..........w.

--------------------------------------------------------------------------------

The only difference between the utilities is the Packet header line, primarily
the utility identifier and the packet sequence formats.

There appear to be 2 formats for packet seqencing

Format 1:

 ... packet nn at DD-MMM-YYYY hh:mm:ss.ss

Format 2:

 ... packet seq # = nn at DD-MMM-YYYY hh:mm:ss.ss

If there are other formats then code will have to be written in parse_vms_rec_hdr()
to handle them.

--------------------------------------------------------------------------------

 */

/* Magic text to check for VMS-ness of file using possible utility names
 *
 */
#define VMS_HDR_MAGIC_STR1	"TCPIPtrace"
#define VMS_HDR_MAGIC_STR2	"TCPtrace"
#define VMS_HDR_MAGIC_STR3	"INTERnet trace"

/* Magic text for start of packet */
#define VMS_REC_MAGIC_STR1	VMS_HDR_MAGIC_STR1
#define VMS_REC_MAGIC_STR2	VMS_HDR_MAGIC_STR2
#define VMS_REC_MAGIC_STR3	VMS_HDR_MAGIC_STR3

#define VMS_HEADER_LINES_TO_CHECK    200
#define VMS_LINE_LENGTH              240

static gboolean vms_read(wtap *wth, int *err, gchar **err_info,
    long *data_offset);
static gboolean vms_seek_read(wtap *wth, long seek_off,
    union wtap_pseudo_header *pseudo_header, guint8 *pd, int len,
    int *err, gchar **err_info);
static gboolean parse_single_hex_dump_line(char* rec, guint8 *buf,
    long byte_offset, int in_off, int remaining_bytes);
static gboolean parse_vms_hex_dump(FILE_T fh, int pkt_len, guint8* buf,
    int *err, gchar **err_info);
static int parse_vms_rec_hdr(wtap *wth, FILE_T fh, int *err, gchar **err_info);

#ifdef TCPIPTRACE_FRAGMENTS_HAVE_HEADER_LINE
/* Seeks to the beginning of the next packet, and returns the
   byte offset.  Returns -1 on failure, and sets "*err" to the error. */
static long vms_seek_next_packet(wtap *wth, int *err)
{
  long cur_off;
  char buf[VMS_LINE_LENGTH];
  
  while (1) {
    cur_off = file_tell(wth->fh);
    if (cur_off == -1) {
      /* Error */
      *err = file_error(wth->fh);
      hdr = NULL;
      return -1;
    }
    if (file_gets(buf, sizeof(buf), wth->fh) != NULL) {
      if (strstr(buf, VMS_REC_MAGIC_STR1) ||
	  strstr(buf, VMS_REC_MAGIC_STR2) ||
	  strstr(buf, VMS_REC_MAGIC_STR2)) {
	strncpy(hdr, buf, VMS_LINE_LENGTH-1);
	hdr[VMS_LINE_LENGTH-1] = '\0';
	return cur_off;
      }
    } else {
      if (file_eof(wth->fh)) {
	/* We got an EOF. */
	*err = 0;
      } else {
	/* We (presumably) got an error (there's no
	   equivalent to "ferror()" in zlib, alas,
	   so we don't have a wrapper to check for
	   an error). */
	*err = file_error(wth->fh);
      }
      break;
    }
  }
  hdr = NULL;
  return -1;
}
#endif /* TCPIPTRACE_FRAGMENTS_HAVE_HEADER_LINE */

/* Look through the first part of a file to see if this is
 * a VMS 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.
 *
 * Leaves file handle at begining of line that contains the VMS Magic
 * identifier.
 */
static gboolean vms_check_file_type(wtap *wth, int *err)
{
  char	buf[VMS_LINE_LENGTH];
  guint	reclen, line;
  long mpos;
  
  buf[VMS_LINE_LENGTH-1] = '\0';
  
  for (line = 0; line < VMS_HEADER_LINES_TO_CHECK; line++) {
    mpos = file_tell(wth->fh);
    if (mpos == -1) {
      /* Error. */
      *err = file_error(wth->fh);
      return FALSE;
    }
    if (file_gets(buf, VMS_LINE_LENGTH, wth->fh) != NULL) {
      
      reclen = strlen(buf);
      if (reclen < strlen(VMS_HDR_MAGIC_STR1) ||
	  reclen < strlen(VMS_HDR_MAGIC_STR2) || 
	  reclen < strlen(VMS_HDR_MAGIC_STR3)) {
	continue;
      }
      
      if (strstr(buf, VMS_HDR_MAGIC_STR1) ||
	  strstr(buf, VMS_HDR_MAGIC_STR2) ||
	  strstr(buf, VMS_HDR_MAGIC_STR3)) {
	/* Go back to the beginning of this line, so we will
	 * re-read it. */
	if (file_seek(wth->fh, mpos, SEEK_SET, err) == -1) {
	  /* Error. */
	  return FALSE;
	}
	return TRUE;
      }
    } else {
      /* EOF or error. */
      if (file_eof(wth->fh))
	*err = 0;
      else
	*err = file_error(wth->fh);
      return FALSE;
    }
  }
  *err = 0;
  return FALSE;
}


int vms_open(wtap *wth, int *err, gchar **err_info _U_)
{
    /* Look for VMS header */
    if (!vms_check_file_type(wth, err)) {
        if (*err == 0)
            return 0;
        else
            return -1;
    }

    wth->data_offset = 0;
    wth->file_encap = WTAP_ENCAP_RAW_IP;
    wth->file_type = WTAP_FILE_VMS;
    wth->snapshot_length = 0; /* not known */
    wth->subtype_read = vms_read;
    wth->subtype_seek_read = vms_seek_read;

    return 1;
}

/* Find the next packet and parse it; called from wtap_read(). */
static gboolean vms_read(wtap *wth, int *err, gchar **err_info,
    long *data_offset)
{
    long   offset = 0;
    guint8    *buf;
    int    pkt_len;

    /* Find the next packet */
#ifdef TCPIPTRACE_FRAGMENTS_HAVE_HEADER_LINE
    offset = vms_seek_next_packet(wth, err);
#else
    offset = file_tell(wth->fh);
#endif
    if (offset < 1)
        return FALSE;

    /* Parse the header */
    pkt_len = parse_vms_rec_hdr(wth, wth->fh, err, err_info);
    if (pkt_len == -1)
	return FALSE;

    /* Make sure we have enough room for the packet */
    buffer_assure_space(wth->frame_buffer, pkt_len);
    buf = buffer_start_ptr(wth->frame_buffer);

    /* Convert the ASCII hex dump to binary data */
    if (!parse_vms_hex_dump(wth->fh, pkt_len, buf, err, err_info))
        return FALSE;

    wth->data_offset = offset;
    *data_offset = offset;
    return TRUE;
}

/* Used to read packets in random-access fashion */
static gboolean
vms_seek_read (wtap *wth, long seek_off,
    union wtap_pseudo_header *pseudo_header _U_,
    guint8 *pd, int len, int *err, gchar **err_info)
{
    int    pkt_len;

    if (file_seek(wth->random_fh, seek_off - 1, SEEK_SET, err) == -1)
        return FALSE;

    pkt_len = parse_vms_rec_hdr(NULL, wth->random_fh, err, err_info);

    if (pkt_len != len) {
        if (pkt_len != -1) {
            *err = WTAP_ERR_BAD_RECORD;
            *err_info = g_strdup_printf("vms: requested length %d doesn't match length %d",
                len, pkt_len);
        }
        return FALSE;
    }

    return parse_vms_hex_dump(wth->random_fh, pkt_len, pd, err, err_info);
}

/* isdumpline assumes that dump lines start with some non-alphanumerics
 * followed by 4 hex numbers - each 8 digits long, each hex number followed
 * by 3 spaces.
 */
static int
isdumpline( gchar *line )
{
    int i, j;

    while (*line && !isalnum((guchar)*line))
	line++;

    for (j=0; j<4; j++) {
	for (i=0; i<8; i++, line++)
	    if (! isxdigit((guchar)*line))
		return FALSE;

	for (i=0; i<3; i++, line++)
	    if (*line != ' ')
		return FALSE;
    }

    return isspace((guchar)*line);
}

/* Parses a packet record header. */
static int
parse_vms_rec_hdr(wtap *wth, FILE_T fh, int *err, gchar **err_info)
{
    char   line[VMS_LINE_LENGTH + 1];
    int    num_items_scanned;
    int	   pkt_len = 0;
    int	   pktnum;
    int	   csec = 101;
    struct tm tm;
    char mon[4] = {'J', 'A', 'N', 0};
    gchar *p;
    static gchar months[] = "JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC";

    tm.tm_year = 1970;
    tm.tm_hour = 1;
    tm.tm_min = 1;
    tm.tm_sec = 1;

    /* Skip lines until one starts with a hex number */
    do {
        if (file_gets(line, VMS_LINE_LENGTH, fh) == NULL) {
            *err = file_error(fh);
	    if ((*err == 0) && (csec != 101)) {
		*err = WTAP_ERR_SHORT_READ;
            }
            return -1;
        }
	line[VMS_LINE_LENGTH] = '\0';

	if ((csec == 101) && (p = strstr(line, "packet "))
	    && (! strstr(line, "could not save "))) {
	    /* Find text in line starting with "packet ". */

	    /* First look for the Format 1 type sequencing */
	    num_items_scanned = sscanf(p,  
		  		       "packet %d at %d-%3s-%d %d:%d:%d.%d",
			  	       &pktnum, &tm.tm_mday, mon,
				       &tm.tm_year, &tm.tm_hour,
				       &tm.tm_min, &tm.tm_sec, &csec);
	    /* Next look for the Format 2 type sequencing */
	    if (num_items_scanned != 8) {
	      num_items_scanned = sscanf(p,
		  		         "packet seq # = %d at %d-%3s-%d %d:%d:%d.%d",
			  	         &pktnum, &tm.tm_mday, mon,
				         &tm.tm_year, &tm.tm_hour,
				         &tm.tm_min, &tm.tm_sec, &csec);
	    }
	    /* if unknown format then exit with error        */
	    /* We will need to add code to handle new format */
	    if (num_items_scanned != 8) {
	        *err = WTAP_ERR_BAD_RECORD;
	        *err_info = g_strdup_printf("vms: header line not valid");
		return -1;
	    }
	}
        if ( (! pkt_len) && (p = strstr(line, "Length"))) {
            p += sizeof("Length ");
            while (*p && ! isdigit((guchar)*p))
                p++;

            if ( !*p ) {
                *err = WTAP_ERR_BAD_RECORD;
	        *err_info = g_strdup_printf("vms: Length field not valid");
                return -1;
            }

            pkt_len = atoi(p);
	    break;
        }
    } while (! isdumpline(line));

    if (wth) {
        p = strstr(months, mon);
        if (p)
            tm.tm_mon = (p - months) / 3;
        tm.tm_year -= 1900;

	tm.tm_isdst = -1;
        wth->phdr.ts.tv_sec = mktime(&tm);

        wth->phdr.ts.tv_usec = csec * 10000;
        wth->phdr.caplen = pkt_len;
        wth->phdr.len = pkt_len;
    }

    return pkt_len;
}

/* Converts ASCII hex dump to binary data */
static gboolean
parse_vms_hex_dump(FILE_T fh, int pkt_len, guint8* buf, int *err,
    gchar **err_info)
{
    gchar line[VMS_LINE_LENGTH + 1];
    int    i;
    int    offset = 0;

    for (i = 0; i < pkt_len; i += 16) {
        if (file_gets(line, VMS_LINE_LENGTH, fh) == NULL) {
            *err = file_error(fh);
            if (*err == 0) {
                *err = WTAP_ERR_SHORT_READ;
            }
            return FALSE;
        }
	line[VMS_LINE_LENGTH] = '\0';
        if (i == 0) {
	    while (! isdumpline(line)) { /* advance to start of hex data */
	        if (file_gets(line, VMS_LINE_LENGTH, fh) == NULL) {
		    *err = file_error(fh);
		    if (*err == 0) {
		        *err = WTAP_ERR_SHORT_READ;
		    }
		    return FALSE;
		}
		line[VMS_LINE_LENGTH] = '\0';
	    }
            while (line[offset] && !isxdigit((guchar)line[offset]))
                offset++;
	}
	if (!parse_single_hex_dump_line(line, buf, i,
					offset, pkt_len - i)) {
            *err = WTAP_ERR_BAD_RECORD;
	    *err_info = g_strdup_printf("vms: hex dump not valid");
            return FALSE;
        }
    }
    /* Avoid TCPIPTRACE-W-BUFFERSFUL, TCPIPtrace could not save n packets.
     * errors. */
    file_gets(line, VMS_LINE_LENGTH, fh);
    return TRUE;
}

/*
          1         2         3         4
0123456789012345678901234567890123456789012345
   50010C0A   A34C0640   00009017   2C000045    0000    E..,....@.L....P
   00000000   14945E52   0A00DC02 | 32010C0A    0010    ...2....R^......
       0000 | B4050402   00003496   00020260    0020    `....4........
*/

#define START_POS    7
#define HEX_LENGTH    ((8 * 4) + 7) /* eight clumps of 4 bytes with 7 inner spaces */
/* 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 TRUE if good hex dump, FALSE if bad.
 */
static gboolean
parse_single_hex_dump_line(char* rec, guint8 *buf, long byte_offset,
               int in_off, int remaining) {

    int        i;
    char        *s;
    int        value;
    static int offsets[16] = {39,37,35,33,28,26,24,22,17,15,13,11,6,4,2,0};
    char lbuf[3] = {0,0,0};


    /* Get the byte_offset directly from the record */
    s = rec;
    value = strtoul(s + 45 + in_off, NULL, 16);

    if (value != byte_offset) {
        return FALSE;
    }

    if (remaining > 16)
	remaining = 16;

    /* Read the octets right to left, as that is how they are displayed
     * in VMS.
     */

    for (i = 0; i < remaining; i++) {
        lbuf[0] = rec[offsets[i] + in_off];
        lbuf[1] = rec[offsets[i] + 1 + in_off];

        buf[byte_offset + i] = (guint8) strtoul(lbuf, NULL, 16);
    }

    return TRUE;
}
