#!/usr/bin/env perl
# -*- perl -*- 
#-----------------------------------------------------------------------
#   Module Name:    $Source: /Users/goeke/programming/perl/crater/RCS/CComment,v $
#   Purpose:        UDP packet stream in; LRO-compatible, CCSDS packet out
#   Language:       Perl 5
#   Assumptions:    Data ICD is 32-02001
#   Part Number:    
#   Author:         Robert F. Goeke (goeke@space.mit.edu
#   References:     
#   Copyright:      Massachusetts Institute of Technology 2006
#-----------------------------------------------------------------------

########################################################################
# Initial Constants
########################################################################
$Version = '$Id: CComment,v 1.2 2007/08/13 13:51:18 goeke Exp goeke $';

require 5.002;
use Socket;
# use File::Copy;
use Time::Local;
use Time::gmtime;

$Epoch = timegm(0,0,0,1,0,2001);    # Epoch for LRO MET
$LeapSec = 1;                       # Occured 1/1/06

$TLM_OUT     = 11403;          # default UDP telemetry output port
$HOST_OUT    = "localhost";    # default output UDP is this host name
$APP_ID      = 123;            # default AppId for comments
$MAXLEN      = 4096;           # max length of UDP packet in bytes

########################################################################
########################################################################
# Main Program executes here
########################################################################
########################################################################

&Setup;
&Doctor;      # should not return

printf STDERR "Zounds!!!!\n";
exit 5;               # Should never get here!

##########################That's all, folks! ###########################
########################################################################

########################################################################
#    Read a packet, add CCSDS header if necessary, and write the result
#    We really are assuming that the input stream contains
#      a) a binary CCSDS packet, which we pass unchanged
#      b) ASCII text to which we add a header and pack
#    Does not return
########################################################################
sub Doctor {
    while(1) {
	if (!defined($TLM_IN)) {
	    &GetStdin;      # packs stdin into $Packet
	} else {
	    &GetPacket;     # copies UDP input into $Packet
	}
	if (&FixPacket) {   # Pass packets which already have headder
	    printf ">> Adding CCSDS header\n" if ($Verbose);
	    &MakePacket;    # Add the CCSDS header
	} else {
	    printf "." if ($Verbose);
	    $Telemetry = $Packet;  # $Packet is assumed to be pre-packed
	}
	&SendPacket;        # Assumes output is in $Telemetry
    }
}

########################################################################
# This answers the question -- does the packet need to be fixed?
#   (header checks taken from "verify"; not exhaustive, but probably adequate)
########################################################################
sub FixPacket {
    $VERSION = '0';
    $TYPE = '0';
    $SECFLAG = '1';
    $SEGFLAG = '3';
    $RESERVED = '0';

    my ($one,$two,$three,$four,$five,$six,@contents) = 
	unpack("nnnnnnC*",$Packet);
    my $version     = 0x07 & $one>>13;
    my $type        = 0x01 & $one>>12;
    my $secFlag     = 0x01 & $one>>11;
    my $appId       = 0x3FF & $one;
    my $segFlag     = 0x03 & $two>>14;
    my $seqCount    = 0x3FFF & $two;
    my $length      = $three;
    my $res1        = 0x01 & $four>>15;
    my $sec_time    = (0x7FFF&$four)<<16 | $five;
    my $subsec_time = 0x0F & $six>>12;
    my $res2        = 0x1F & $six>>7;
    my $test        = 0x01 & $six>>6;
    my $tick        = 0x01 & $six>>5;
    my $sn          = 0x1F & $six;

    return 0 if ( $version==$VERSION && $type==$TYPE && 
		  $secFlag==$SECFLAG && $segFlag==$SEGFLAG &&
		  $res1==$RESERVED && $res2==$RESERVED &&
		  $appId>119 && $appId<130 );
    # So the packet needs a header
    return 1;
}

########################################################################
# Get a complete packet -> $packet
########################################################################
sub GetPacket {
    recv(INSTUFF, $Packet, $MAXLEN, 0) || die $!;
}

########################################################################
# Get a complete packet -> $packet
########################################################################
sub GetStdin {
    my $in_line =  <>;
    chop($in_line);

    if (length($in_line)>$MAXLEN) {
	printf STDERR ">> Input line on STDIN too long; IGNORED\n";
	$in_line = "INPUT LINE ERROR";
    }

    printf ">> STDIN: $in_line\n" if ($Verbose>1);
    $Packet = pack("A*",$in_line);
}

########################################################################
# The general HELP! message
# Short if $Verbose = 0, else not
# NB this subroutine does not return
########################################################################
sub Help {
    print "
usage: $0 [-a AppId] [-h] [-p UDP_in] [-m out_to] [-q UDP_out] [-v]
";
    exit if (!$Verbose);

    print "
flag: -a specify AppID to be placed in CCSDS header [$APP_ID]
      -h displays this message
      -p selects port for input telemetry stream [$TLM_IN]
      -m selects machine name for output telemetry stream [$HOST_OUT]
      -q selects port for output telemetry stream [$TLM_OUT]
      -v specifies verbose operation

Program accepts text from STDIN, adds an appropriate CRaTER-style CCSDS
  telemetry header, and emits the result as a UDP packet. Lines must be 
  newline terminated and less than $MAXLEN characters long.

When used with the -p flag to set an input port for UDP packets, the 
  program adds, only if necessary, the CCSDS header; in this case STDIN
  is ignored.
";

    exit;
}

########################################################################
# Convert LRO time to local version
########################################################################
sub Localtime {
    my ($sec,$min,$hour,$mday,$mon,$year) = localtime($Epoch + $_[0]);
    return sprintf("%02d:%02d:%02d %d/%d/%02d", 
		   $hour, $min, $sec, $mon+1, $mday, $year-100);
}

########################################################################
# Add a header to these contents
#  (Taken from "primary-packet")
########################################################################
sub MakePacket {

### CCSDS Primary Header is 3 words long; last 2 must be set later
    my $c_version   = 0;   # CCSDS Version Number
    my $c_type      = 0;   # CCSDS "1" for Telecommand
    my $c_secFlag   = 1;   # CCSDS "1" for secondary header present
    my $c_appId;           # CCSDS CRaTER Application ID
    my $c_segFlag   = 3;   # CCSDS "3" to indicate no segmentation
# $c_seqCount;         # CCSDS incremented for each packet sent
                       # NB this is a global so it saves state to increment
    my $c_length;          # CCSDS byes following primary header - 1

# my $CCSDS_Pone = $c_version<<13 | $c_type<<12 | $c_secFlag<<11 | $c_appId ;
# $CCSDS_Ptwo = $c_segFlag<<14 | $c_seqCount ;
# $CCSDS_Pthree = $c_length;

### CCSDS Secondary Header is 3 words long
# $s_reserved_0  = 0;      # bit  48:      "0" means non-standard header
# $s_time_sec;             # bits 49-79:   s/c time in seconds
    my $s_time_subsec   = 0;      # bits 80-83:   s/c time in subseconds
# $s_reserved_1  = 0;      # bits 84-88:   constant 0
    my $s_test_mode     = 0;      # bit  89:      "1" means in test mode
    my $s_oneHertz      = 0;      # bit  90:      1 Hz tick received
    my $s_serialNo      = 0;      # bits 91-95:   Instrument Serial No. 
# $CCSDS_Sone     =  $s_time_sec&0x7FFFFFFF;
# $CCSDS_Stwo     =  $s_time_sbsec<<11 | $s_oneHertz<<5 | $s_serialno;

    $c_appId = $APP_ID;
    my $CCSDS_Pone = $c_version<<13 | $c_type<<12 | $c_secFlag<<11 | $c_appId ;

    # This should roll properly in the following pack()
    my $CCSDS_Ptwo = $c_segFlag<<14 | $c_seqCount++ ;

    $c_length = 5 + length($Packet);
    my $CCSDS_Pthree   = $c_length;

    $s_time_sec = time() - $Epoch + $LeapSec; 
    my $CCSDS_Sone     =  $s_time_sec & 0x7FFFFFFF;
    my $CCSDS_Stwo     =  ($s_time_subsec&0x0F)<<12 | 
	                $s_test_mode<<6 |
	                $s_oneHertz<<5 | 
			$s_serialNo;

    $Telemetry = pack("n n n N n", 
		      $CCSDS_Pone,$CCSDS_Ptwo,$CCSDS_Pthree,
		      $CCSDS_Sone,$CCSDS_Stwo);
    $Telemetry = $Telemetry.$Packet;
}


########################################################################
# Send a complete packet contained in $Telemetry
########################################################################
sub SendPacket {
    send(OUTSTUFF,$Telemetry,0,$Portaddr) || die $!;
}

########################################################################
# Process all the command line arguments
# Open input and output files
########################################################################
sub Setup {

    $Verbose = 0;

    my ($foo,$jj);
    local ($inport);

    while ( $foo = shift(@ARGV) ) {
	if ( $foo =~ /^-[aA]/ ) {       # Specify appid
	    if ( !defined($APP_ID=shift(@ARGV)) || $APP_ID =~ /[^0-9]/) {
		print STDERR "Flag $foo requires a numeric argument\n";
		&Help;
	    }
	    next;
	}
	if ( $foo =~ /^-[hH]/ ) {       # Ask for help
	    $Verbose++;
	    &Help;
	}
	if ( $foo =~ /^-[mM]/ ) {       # Specify target output machine
	    if ( !defined($HOST_OUT=shift(@ARGV)) ) {
		print STDERR "Flag $foo requires an argument\n";
		&Help;
	    }
	    next;
	}
	if ( $foo =~ /^-[pP]/ ) {       # Specify input port
	    if ( !defined($TLM_IN=shift(@ARGV)) || $TLM_IN =~ /[^0-9]/) {
		print STDERR "Flag $foo requires a numeric argument\n";
		&Help;
	    }
	    $inport++;                  # used as a sanity check later
	    next;
	}
	if ( $foo =~ /^-[qQ]/ ) {       # Specify output port
	    if ( !defined($TLM_OUT=shift(@ARGV)) || $TLM_OUT =~ /[^0-9]/) {
		print STDERR "Flag $foo requires a numeric argument\n";
		&Help;
	    }
	    next;
	}
	if ( $foo =~ /^-[vV]/ ) {
	    $Verbose++;
	    next;
	} 
	print STDERR "Unknown argument: $foo\n";
	&Help;
    }

    print ">> $Version\n" if ($Verbose);

    if ($APP_ID<123 || $APP_ID>126) {
	printf STDERR "AppId must be in the range 123 to 125\n";
	exit 2;
    }

    if (!defined($TLM_IN)) {
	print ">> Taking input from STDIN\n" if ($Verbose);
    } else {
	socket(INSTUFF, PF_INET, SOCK_DGRAM, getprotobyname('udp')) || di $!;
	bind(INSTUFF, sockaddr_in($TLM_IN,INADDR_ANY)) || die $!;
	print ">> Accepting packets on socket $TLM_IN\n" if ($Verbose);
    }

    # we establish, but do not bind this socket
    socket(OUTSTUFF, PF_INET, SOCK_DGRAM, getprotobyname('udp')) || die $!;
    $Portaddr = sockaddr_in($TLM_OUT,inet_aton("$HOST_OUT"));
    print ">> Writing on socket $TLM_OUT to $HOST_OUT\n" if ($Verbose);
}

########################################################################
# Pod follows
########################################################################

=for html 
<head><title>CRaTER -- CComment</title></head>

=head2 NAME

B<CComment> -- CRaTER data merge into packet stream

=head2 USAGE

     CComment [-a AppId] [-h] [-p UDP_in] [-m out_to] [-q UDP_out] [-v]

=head2 FLAGS

      -a sets AppId [123]
      -h displays this message
      -p selects port for input telemetry stream; cancels STDIN
      -m selects machine name to which output stream is directed [localhost]
      -q selects port to which output stream is directed [11403]
      -v selects verbose operation

=head2 DESCRIPTION

Program accepts text from STDIN and formats each line into a separate
  CRaTER-style CCSDS telemetry packet, stripping off the trailing 
  newline.  The maximum line length is restricted to 4096 characters.  
  If an input data stream port 
  is selected via the B<-p> flag, the each received UDP packet is 
  screened for a proper 12-byte header.  If the header is present, the
  packet is passed unchanged.  If the header is absent, one is added.

If a new header is required, the time inserted will be the current 
  machine time, translated to the LRO epoch.

=head2 ENVIRONMENT

    perl5.002     Minimum version of Perl interpreter required
    CRATER_GSE    Environment variable containing EGSE machine name

=head2 BUGS

There are implicit assumptions that the input to be formatted into
  UDP packets is newline-terminated ASCII strings.

=head2 SEE ALSO

rtlm

=head2 AUTHOR

Bob Goeke

=head2 RCS Information

$Id: CComment,v 1.2 2007/08/13 13:51:18 goeke Exp goeke $

=cut

########################################################################
# history follows
########################################################################
#   $Log: CComment,v $
#   Revision 1.2  2007/08/13 13:51:18  goeke
#   Restrict appids to 123-126
#
#   Revision 1.1  2007/08/11 14:40:02  goeke
#   Initial revision
#
#   Revision 3.14  2007/06/22 17:34:09  goeke
#   Add -z flag
#
#   Revision 3.13  2007/06/14 16:00:47  goeke
#   Fix appId selection for packet diagnostics
#
#   Revision 3.12  2007/06/14 15:55:59  goeke
#   Add diagnostic for packets with bad (CRaTER) appIds
#
#   Revision 3.11  2007/05/29 20:04:43  goeke
#   Fixed bug in &GetOneSecond; now does &Spray every time.
#
#   Revision 3.10  2007/05/24 14:45:04  goeke
#   Fixed format of "echo" and "mask" output in -R mode
#   Changed logic for detecting end-of-file so that sync will work
#     over the 64-byte header (which starts off with NULs)
#   Added verbose display of last packet time.
#
#   Revision 3.9  2007/05/03 15:07:35  goeke
#   Added time message to "F" command in file-stepping mode;
#   Fixed exit bug in file-stepping mode
#
#   Revision 3.8  2007/04/17 15:36:16  goeke
#   Add POD
#
#   Revision 3.7  2007/02/26 13:40:37  goeke
#   Fixed bug in emitting WARN for too many sockets open
#
#   Revision 3.6  2007/02/23 16:59:48  goeke
#   Added "end of message" mark to "state" response
#
#   Revision 3.5  2007/02/23 16:39:30  goeke
#   "state" now returns machine's name instead of IP address
#
#   Revision 3.4  2006/11/01 13:33:45  goeke
#   Fix typo in &Setup opening input telemetry channel
#
#   Revision 3.3  2006/10/31 21:54:36  goeke
#   Fix bug in display of active AppIds
#
#   Revision 3.2  2006/10/30 23:17:37  goeke
#   Separated out the -r and -R versions of file retrieval
#
#   Revision 3.1  2006/10/30 22:23:58  goeke
#   Start new major rev incorporating LRO-standard archive file retrieval
#
#   Revision 2.12  2006/10/30 22:19:28  goeke
#   Fixed bug in -h flag; added -x flag
#   Now first packet is used to set $lasttime
#
#   Revision 2.11  2006/10/30 20:28:16  goeke
#   Add -e flag
#
#   Revision 2.10  2006/10/30 19:43:16  goeke
#   Add ability to scroll through LRO-standard data files
#
#   Revision 2.9  2006/10/13 15:26:37  goeke
#   Add EXTRACT command
#   More error checking on appid numbers (but "foo" still works?)
#
#   Revision 2.8  2006/09/29 20:27:15  goeke
#   Fix bugs in close commands
#   Eliminate the "flow" command and do all opens immediate
#
#   Revision 2.7  2006/09/07 20:42:18  goeke
#   Added HELP response to UDP user.
#
#   Revision 2.6  2006/09/07 20:28:35  goeke
#   Added STATE command
#   Implemented -p, -P, -s, -S commands
#
#   Revision 2.5  2006/09/07 19:53:28  goeke
#   Fix bug in CLOSE port_number
#
#   Revision 2.4  2006/09/07 19:39:20  goeke
#   Updated help(); took out signal handler as unnecessary.
#   Added CLOSE port_number feature
#
#   Revision 2.3  2006/09/07 18:44:43  goeke
#   Seems to work; need to clean up help
#
#   Revision 2.2  2006/09/07 18:28:50  goeke
#   Distributes packets OK, but CLOSE isn't working
#
#   Revision 2.1  2006/09/07 15:47:57  goeke
#