test/vfycksum.pl - net/ipfilter - Rivoreo Source Code Repositories


 #
 # validate the IPv4 header checksum.
 # $bytes[] is an array of 16bit values, with $cnt elements in the array.
 #
 sub dump {
 	print "\n";
 	for ($i = 0; $i < $#bytes; $i++) {
 		printf "%04x ", $bytes[$i];
 	}
 	print "\n";
 }

 sub dosum {
 	local($seed) = $_[0];
 	local($start) = $_[1];
 	local($max) = $_[2];
 	local($idx) = $start;
 	local($lsum) = $seed;

 	for ($idx = $start, $lsum = $seed; $idx < $max; $idx++) {
 		$lsum += $bytes[$idx];
 	}
 	$lsum = ($lsum & 0xffff) + ($lsum >> 16);
 	$lsum = ~$lsum & 0xffff;
 	return $lsum;
 }


 sub ipv4addrsum {
 	local($b) = $_[0];
 	local($as) = 0;

 	$as += $bytes[$b + 6];	# source address
 	$as += $bytes[$b + 7];
 	$as += $bytes[$b + 8];	# destination address
 	$as += $bytes[$b + 9];
 	return ($as);
 }

 sub ipv6addrsum {
 	local($b) = $_[0];
 	local($as) = 0;

 	$as += $bytes[$b + 4];	# source address
 	$as += $bytes[$b + 5];
 	$as += $bytes[$b + 6];
 	$as += $bytes[$b + 7];
 	$as += $bytes[$b + 8];
 	$as += $bytes[$b + 9];
 	$as += $bytes[$b + 10];
 	$as += $bytes[$b + 11];
 	$as += $bytes[$b + 12];	# destination address
 	$as += $bytes[$b + 13];
 	$as += $bytes[$b + 14];
 	$as += $bytes[$b + 15];
 	$as += $bytes[$b + 16];
 	$as += $bytes[$b + 17];
 	$as += $bytes[$b + 18];
 	$as += $bytes[$b + 19];
 	return ($as);
 }

 sub tcpcommon {
 	local($base) = $_[0];
 	local($hl) = $_[1];
 	local($hs) = $_[2];
 	local($lenoffset) = $_[3];

 	local($thl) = $bytes[$base + $hl + 6];
 	$thl &= 0xf0;
 	$thl >>= 2;

 	local($x) = $bytes[$base + $lenoffset];
 	local($y) = ($cnt - $base) * 2;
 	local($z) = 0;

 	if ($bytes[$base + $lenoffset] > ($cnt - $base) * 2) {
 		print "[cnt=$cnt base=$base]";
 		$x = $bytes[$base + $lenoffset];
 		$y = ($cnt - $base) * 2;
 		$z = 1;
 	} elsif (($cnt - $base) * 2 < $hl + $hl) {
 		$x = ($cnt - $base) * 2;
 		$y = $hl + 20;
 		$z = 2;
 	} elsif (($cnt - $base) * 2 < $hl + $thl) {
 		$x = ($cnt - $base) * 2;
 		$y = $hl + $thl;
 		$z = 3;
 	} elsif ($len < $thl) {
 		$x = ($cnt - $base) * 2;
 		$y = $len;
 		$z = 4;
 	} elsif (($cnt - $base) * 2 < 20) {
 		$x = ($cnt - $base) * 2;
 		$y = $len;
 		$z = 5;
 	}

 	if ($z) {
 		print " TCP: missing data($x $y $z) $hl";
 #		&dump();
 		return;
 	}

 	local($tcpat) = $base + $hl;
 	$hs = &dosum($_[2], $tcpat, $cnt);
 	if ($hs != 0) {
 		local($osum) = $bytes[$tcpat + 8];
 		$bytes[$base + $hl + 8] = 0;
 		local($hs2) = &dosum($_[2], $tcpat, $cnt);
 		$bytes[$tcpat + 8] = $osum;
 		printf " TCP: (%x) %x != %x", $hs, $osum, $hs2;
 	} else {
 		print " TCP: ok ($x $y)";
 	}
 }

 sub udpcommon {
 	local($base) = $_[0];
 	local($hl) = $_[1];
 	local($hs) = $_[2];

 	if ($bytes[$base + 1] > ($cnt - $base) * 2) {
 		print " UDP: missing data(1)";
 		return;
 	} elsif ($bytes[$base + 1] < ($hl << 1) + 8) {
 		print " UDP: missing data(2)";
 		return;
 	} elsif (($cnt - $base) * 2 < ($hl << 1) + 8) {
 		print " UDP: missing data(3)";
 		return;
 	}

 	local($udpat) = $base + $hl;
 	$hs = &dosum($udpsum, $udpat, $cnt);
 	local($osum) = $bytes[$udpat + 3];

 	#
 	# It is valid for UDP packets to have a 0 checksum field.
 	# If it is 0, then display what it would otherwise be.
 	#
 	if ($osum == 0) {
 		printf " UDP: => %x", $hs;
 	} elsif ($hs != 0) {
 		$bytes[$udpat + 3] = 0;
 		local($hs2) = &dosum($udpsum, $udpat, $cnt);
 		$bytes[$udpat + 3] = $osum;
 		printf " UDP: (%x) %x != %x", $hs, $osum, $hs2;
 	} else {
 		print " UDP: ok";
 	}
 }

 sub ipv6check {
 	local($base) = $_[0];
 	$hl = $bytes[$base] / 256;
 	return if (($hl >> 4) != 6);	# IPv4 ?
 	$hl = 40;

 	print " IPv6($base): ok ";

 	if (($bytes[$base + 3] >> 8) == 6) {
 		&tcpcheck6($base);
 	} elsif (($bytes[$base + 3] >> 8) == 58) {
 		&icmpcheck6($base);
 	}
 	print "\n";
 }

 sub tcpcheck6 {
 	local($base) = $_[0];
 	local($hl) = $bytes[$base] / 256;
 	return if (($hl >> 4) != 6);
 	$hl = 20;

 	local($hs) = 6;	# TCP
 	local($len) = $bytes[$base + 2];
 	$hs += $len;
 	$hs += &ipv6addrsum($base);

 	&tcpcommon($base, $hl, $hs, 2);
 }

 sub icmpcheck6 {
 	local($base) = $_[0];
 	local($hl) = 20;

 	local($hs) = 58;	# ICMP6
 	local($len) = $bytes[$base + 2];
 	$hs += $len;
 	$hs += &ipv6addrsum($base);

 	local($len) = $bytes[$base + 1] - ($hl << 1);

 	if ($bytes[$base + 2] > ($cnt - $base) * 2) {
 		print " ICMPv6: missing data(1)";
 		return;
 	} elsif ($bytes[$base + 2] < 8) {
 		print " ICMPv6: missing data(2)";
 		return;
 	}

 	local($osum) = $bytes[$base + $hl + 1];
 	$bytes[$base + $hl + 1] = 0;
 	local($hs2) = &dosum($hs, $base + $hl, $cnt);
 	$bytes[$base + $hl + 1] = $osum;

 	if ($osum != $hs2) {
 		printf " ICMPv6: (%x) %x != %x", $hs, $osum, $hs2;
 	} else {
 		print " ICMPv6: ok";
 	}
 #	if ($base == 0) {
 #		$type = $bytes[$hl] >> 8;
 #		if ($type == 3 || $type == 4 || $type == 5 ||
 #		    $type == 11 || $type == 12) {
 #			&ipv4check($hl + 4);
 #		}
 #	}
 }

 sub ipv4check {
 	local($base) = $_[0];
 	$hl = $bytes[$base] / 256;
 	if (($hl >> 4) == 6) {
 		&ipv6check($_[0]);
 	}
 	return if (($hl >> 4) != 4);	# IPv4 ?
 	$hl &= 0xf;
 	$hl <<= 1;			# get the header length in 16bit words

 	$hs = &dosum(0, $base, $base + $hl);
 	$osum = $bytes[$base + 5];

 	if ($hs != 0) {
 		$bytes[$base + 5] = 0;
 		$hs2 = &dosum(0, $base, $base + $hl);
 		$bytes[$base + 5] = $osum;
 		printf " IPv4: ($hl,%x) %x != %x", $hs, $osum, $hs2;
 	} else {
 		print " IPv4($base): ok ";
 	}

 	#
 	# Recognise TCP & UDP and calculate checksums for each of these.
 	#
 	if (($bytes[$base + 4] & 0xff) == 4) {
 		&ipv4check($hl);
 	}
 	if (($bytes[$base + 4] & 0xff) == 6) {
 		&tcpcheck($base);
 	}

 	if (($bytes[$base + 4] & 0xff) == 17) {
 		&udpcheck($base);
 	}

 	if (($bytes[$base + 4] & 0xff) == 1) {
 		&icmpcheck($base);
 	}
 	if ($base == 0) {
 		print "\n";
 	}
 }

 sub tcpcheck {
 	local($base) = $_[0];
 	local($hl) = $bytes[$base] / 256;
 	return if (($hl >> 4) != 4);
 	if ($bytes[$base + 3] & 0x3fff) {
 		print " TCP: fragment";
 		return;
 	}
 	$hl &= 0xf;
 	$hl <<= 1;

 	local($hs) = 6;	# TCP
 	local($len) = $bytes[$base + 1] - ($hl << 1);
 	$hs += $len;
 	$hs += &ipv4addrsum($base);

 	&tcpcommon($base, $hl, $hs, 1);
 }

 sub udpcheck {
 	local($base) = $_[0];
 	local($hl) = $bytes[0] / 256;
 	return if (($hl >> 4) != 4);
 	if ($bytes[$base + 3] & 0x3fff) {
 		print " UDP: fragment";
 		return;
 	}
 	$hl &= 0xf;
 	$hl <<= 1;

 	local($hs) = 17;	# UDP
 	local($len) = $bytes[$base + 1] - ($hl << 1);
 	$hs += $len;
 	$hs += &ipv4addrsum($base);
 	local($udpsum) = $hs;
 	&udpcommon($base, $hl, $hs);
 }

 sub icmpcheck {
 	local($base) = $_[0];
 	local($hl) = $bytes[$base + 0] / 256;
 	return if (($hl >> 4) != 4);
 	return if ($bytes[3] & 0x1fff);
 	$hl &= 0xf;
 	$hl <<= 1;

 	local($hs);
 	local($hs2);

 	local($len) = $bytes[$base + 1] - ($hl << 1);

 	if ($bytes[$base + 1] > ($cnt - $base) * 2) {
 		print " ICMP: missing data(1)";
 		return;
 	} elsif ($bytes[$base + 1] < ($hl << 1) + 8) {
 		print " ICMP: missing data(2)";
 		return;
 	} elsif (($cnt - $base) * 2 < ($hl << 1) + 8) {
 		print " ICMP: missing data(3)";
 		return;
 	}

 	local($osum) = $bytes[$base + $hl + 1];
 	$bytes[$base + $hl + 1] = 0;
 	$hs2 = &dosum(0, $base + $hl, $cnt);
 	$bytes[$base + $hl + 1] = $osum;

 	if ($osum != $hs2) {
 		printf " ICMP: (%x) %x != %x", $hs, $osum, $hs2;
 	} else {
 		print " ICMP: ok";
 	}
 	if ($base == 0) {
 		$type = $bytes[$hl] >> 8;
 		if ($type == 3 || $type == 4 || $type == 5 ||
 		    $type == 11 || $type == 12) {
 			&ipv4check($hl + 4);
 		}
 	}
 }

 while ($#ARGV >= 0) {
 	open(I, "$ARGV[0]") || die $!;
 	print "--- $ARGV[0] ---\n";
 	$multi = 0;
 	while (<I>) {
 		chop;
 		s/#.*//g;

 		#
 		# If the first non-comment, non-empty line of input starts
 		# with a '[', then allow the input to be a multi-line hex
 		# string, otherwise it has to be all on one line.
 		#
 		if (/^\[/) {
 			$multi=1;
 			s/^\[[^]]*\]//g;

 		}
 		s/^ *//g;
 		if (length == 0) {
 			next if ($cnt == 0);
 			&ipv4check(0);
 			$cnt = 0;
 			$multi = 0;
 			next;
 		}

 		#
 		# look for 16 bits, represented with leading 0's as required,
 		# in hex.
 		#
 		s/\t/ /g;
 		while (/^[0-9a-fA-F][0-9a-fA-F] [0-9a-fA-F][0-9a-fA-F] .*/) {
 			s/^([0-9a-fA-F][0-9a-fA-F]) ([0-9a-fA-F][0-9a-fA-F]) (.*)/$1$2 $3/;
 		}
 		while (/.* [0-9a-fA-F][0-9a-fA-F] [0-9a-fA-F][0-9a-fA-F] .*/) {
 $b=$_;
 			s/(.*?) ([0-9a-fA-F][0-9a-fA-F]) ([0-9a-fA-F][0-9a-fA-F]) (.*)/$1 $2$3 $4/g;
 		}
 		if (/.* [0-9a-fA-F][0-9a-fA-F] [0-9a-fA-F][0-9a-fA-F]/) {
 $b=$_;
 			s/(.*?) ([0-9a-fA-F][0-9a-fA-F]) ([0-9a-fA-F][0-9a-fA-F])/$1 $2$3/g;
 		}
 		while (/^[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F].*/) {
 			$x = $_;
 			$x =~ s/([0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]).*/$1/;
 			$x =~ s/ *//g;
 			$y = hex $x;
 			s/[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F] *(.*)/$1/;
 			$bytes[$cnt] = $y;
 #print "bytes[$cnt] = $x\n";
 			$cnt++;
 		}

 		#
 		# Pick up stragler bytes.
 		#
 		if (/^[0-9a-fA-F][0-9a-fA-F]/) {
 			$y = hex $_;
 			$bytes[$cnt++] = $y * 256;
 		}
 		if ($multi == 0 && $cnt > 0) {
 			&ipv4check(0);
 			$cnt = 0;
 		}
 	}

 	if ($cnt > 0) {
 		&ipv4check(0);
 	}
 	close(I);
 	shift(@ARGV);
 }

	#
	# validate the IPv4 header checksum.
	# $bytes[] is an array of 16bit values, with $cnt elements in the array.
	#
	sub dump {
	print "\n";
	for ($i = 0; $i < $#bytes; $i++) {
	printf "%04x ", $bytes[$i];
	}
	print "\n";
	}

	sub dosum {
	local($seed) = $_[0];
	local($start) = $_[1];
	local($max) = $_[2];
	local($idx) = $start;
	local($lsum) = $seed;

	for ($idx = $start, $lsum = $seed; $idx < $max; $idx++) {
	$lsum += $bytes[$idx];
	}
	$lsum = ($lsum & 0xffff) + ($lsum >> 16);
	$lsum = ~$lsum & 0xffff;
	return $lsum;
	}


	sub ipv4addrsum {
	local($b) = $_[0];
	local($as) = 0;

	$as += $bytes[$b + 6]; # source address
	$as += $bytes[$b + 7];
	$as += $bytes[$b + 8]; # destination address
	$as += $bytes[$b + 9];
	return ($as);
	}

	sub ipv6addrsum {
	local($b) = $_[0];
	local($as) = 0;

	$as += $bytes[$b + 4]; # source address
	$as += $bytes[$b + 5];
	$as += $bytes[$b + 6];
	$as += $bytes[$b + 7];
	$as += $bytes[$b + 8];
	$as += $bytes[$b + 9];
	$as += $bytes[$b + 10];
	$as += $bytes[$b + 11];
	$as += $bytes[$b + 12]; # destination address
	$as += $bytes[$b + 13];
	$as += $bytes[$b + 14];
	$as += $bytes[$b + 15];
	$as += $bytes[$b + 16];
	$as += $bytes[$b + 17];
	$as += $bytes[$b + 18];
	$as += $bytes[$b + 19];
	return ($as);
	}

	sub tcpcommon {
	local($base) = $_[0];
	local($hl) = $_[1];
	local($hs) = $_[2];
	local($lenoffset) = $_[3];

	local($thl) = $bytes[$base + $hl + 6];
	$thl &= 0xf0;
	$thl >>= 2;

	local($x) = $bytes[$base + $lenoffset];
	local($y) = ($cnt - $base) * 2;
	local($z) = 0;

	if ($bytes[$base + $lenoffset] > ($cnt - $base) * 2) {
	print "[cnt=$cnt base=$base]";
	$x = $bytes[$base + $lenoffset];
	$y = ($cnt - $base) * 2;
	$z = 1;
	} elsif (($cnt - $base) * 2 < $hl + $hl) {
	$x = ($cnt - $base) * 2;
	$y = $hl + 20;
	$z = 2;
	} elsif (($cnt - $base) * 2 < $hl + $thl) {
	$x = ($cnt - $base) * 2;
	$y = $hl + $thl;
	$z = 3;
	} elsif ($len < $thl) {
	$x = ($cnt - $base) * 2;
	$y = $len;
	$z = 4;
	} elsif (($cnt - $base) * 2 < 20) {
	$x = ($cnt - $base) * 2;
	$y = $len;
	$z = 5;
	}

	if ($z) {
	print " TCP: missing data($x $y $z) $hl";
	# &dump();
	return;
	}

	local($tcpat) = $base + $hl;
	$hs = &dosum($_[2], $tcpat, $cnt);
	if ($hs != 0) {
	local($osum) = $bytes[$tcpat + 8];
	$bytes[$base + $hl + 8] = 0;
	local($hs2) = &dosum($_[2], $tcpat, $cnt);
	$bytes[$tcpat + 8] = $osum;
	printf " TCP: (%x) %x != %x", $hs, $osum, $hs2;
	} else {
	print " TCP: ok ($x $y)";
	}
	}

	sub udpcommon {
	local($base) = $_[0];
	local($hl) = $_[1];
	local($hs) = $_[2];

	if ($bytes[$base + 1] > ($cnt - $base) * 2) {
	print " UDP: missing data(1)";
	return;
	} elsif ($bytes[$base + 1] < ($hl << 1) + 8) {
	print " UDP: missing data(2)";
	return;
	} elsif (($cnt - $base) * 2 < ($hl << 1) + 8) {
	print " UDP: missing data(3)";
	return;
	}

	local($udpat) = $base + $hl;
	$hs = &dosum($udpsum, $udpat, $cnt);
	local($osum) = $bytes[$udpat + 3];

	#
	# It is valid for UDP packets to have a 0 checksum field.
	# If it is 0, then display what it would otherwise be.
	#
	if ($osum == 0) {
	printf " UDP: => %x", $hs;
	} elsif ($hs != 0) {
	$bytes[$udpat + 3] = 0;
	local($hs2) = &dosum($udpsum, $udpat, $cnt);
	$bytes[$udpat + 3] = $osum;
	printf " UDP: (%x) %x != %x", $hs, $osum, $hs2;
	} else {
	print " UDP: ok";
	}
	}

	sub ipv6check {
	local($base) = $_[0];
	$hl = $bytes[$base] / 256;
	return if (($hl >> 4) != 6); # IPv4 ?
	$hl = 40;

	print " IPv6($base): ok ";

	if (($bytes[$base + 3] >> 8) == 6) {
	&tcpcheck6($base);
	} elsif (($bytes[$base + 3] >> 8) == 58) {
	&icmpcheck6($base);
	}
	print "\n";
	}

	sub tcpcheck6 {
	local($base) = $_[0];
	local($hl) = $bytes[$base] / 256;
	return if (($hl >> 4) != 6);
	$hl = 20;

	local($hs) = 6; # TCP
	local($len) = $bytes[$base + 2];
	$hs += $len;
	$hs += &ipv6addrsum($base);

	&tcpcommon($base, $hl, $hs, 2);
	}

	sub icmpcheck6 {
	local($base) = $_[0];
	local($hl) = 20;

	local($hs) = 58; # ICMP6
	local($len) = $bytes[$base + 2];
	$hs += $len;
	$hs += &ipv6addrsum($base);

	local($len) = $bytes[$base + 1] - ($hl << 1);

	if ($bytes[$base + 2] > ($cnt - $base) * 2) {
	print " ICMPv6: missing data(1)";
	return;
	} elsif ($bytes[$base + 2] < 8) {
	print " ICMPv6: missing data(2)";
	return;
	}

	local($osum) = $bytes[$base + $hl + 1];
	$bytes[$base + $hl + 1] = 0;
	local($hs2) = &dosum($hs, $base + $hl, $cnt);
	$bytes[$base + $hl + 1] = $osum;

	if ($osum != $hs2) {
	printf " ICMPv6: (%x) %x != %x", $hs, $osum, $hs2;
	} else {
	print " ICMPv6: ok";
	}
	# if ($base == 0) {
	# $type = $bytes[$hl] >> 8;
	# if ($type == 3 \|\| $type == 4 \|\| $type == 5 \|\|
	# $type == 11 \|\| $type == 12) {
	# &ipv4check($hl + 4);
	# }
	# }
	}

	sub ipv4check {
	local($base) = $_[0];
	$hl = $bytes[$base] / 256;
	if (($hl >> 4) == 6) {
	&ipv6check($_[0]);
	}
	return if (($hl >> 4) != 4); # IPv4 ?
	$hl &= 0xf;
	$hl <<= 1; # get the header length in 16bit words

	$hs = &dosum(0, $base, $base + $hl);
	$osum = $bytes[$base + 5];

	if ($hs != 0) {
	$bytes[$base + 5] = 0;
	$hs2 = &dosum(0, $base, $base + $hl);
	$bytes[$base + 5] = $osum;
	printf " IPv4: ($hl,%x) %x != %x", $hs, $osum, $hs2;
	} else {
	print " IPv4($base): ok ";
	}

	#
	# Recognise TCP & UDP and calculate checksums for each of these.
	#
	if (($bytes[$base + 4] & 0xff) == 4) {
	&ipv4check($hl);
	}
	if (($bytes[$base + 4] & 0xff) == 6) {
	&tcpcheck($base);
	}

	if (($bytes[$base + 4] & 0xff) == 17) {
	&udpcheck($base);
	}

	if (($bytes[$base + 4] & 0xff) == 1) {
	&icmpcheck($base);
	}
	if ($base == 0) {
	print "\n";
	}
	}

	sub tcpcheck {
	local($base) = $_[0];
	local($hl) = $bytes[$base] / 256;
	return if (($hl >> 4) != 4);
	if ($bytes[$base + 3] & 0x3fff) {
	print " TCP: fragment";
	return;
	}
	$hl &= 0xf;
	$hl <<= 1;

	local($hs) = 6; # TCP
	local($len) = $bytes[$base + 1] - ($hl << 1);
	$hs += $len;
	$hs += &ipv4addrsum($base);

	&tcpcommon($base, $hl, $hs, 1);
	}

	sub udpcheck {
	local($base) = $_[0];
	local($hl) = $bytes[0] / 256;
	return if (($hl >> 4) != 4);
	if ($bytes[$base + 3] & 0x3fff) {
	print " UDP: fragment";
	return;
	}
	$hl &= 0xf;
	$hl <<= 1;

	local($hs) = 17; # UDP
	local($len) = $bytes[$base + 1] - ($hl << 1);
	$hs += $len;
	$hs += &ipv4addrsum($base);
	local($udpsum) = $hs;
	&udpcommon($base, $hl, $hs);
	}

	sub icmpcheck {
	local($base) = $_[0];
	local($hl) = $bytes[$base + 0] / 256;
	return if (($hl >> 4) != 4);
	return if ($bytes[3] & 0x1fff);
	$hl &= 0xf;
	$hl <<= 1;

	local($hs);
	local($hs2);

	local($len) = $bytes[$base + 1] - ($hl << 1);

	if ($bytes[$base + 1] > ($cnt - $base) * 2) {
	print " ICMP: missing data(1)";
	return;
	} elsif ($bytes[$base + 1] < ($hl << 1) + 8) {
	print " ICMP: missing data(2)";
	return;
	} elsif (($cnt - $base) * 2 < ($hl << 1) + 8) {
	print " ICMP: missing data(3)";
	return;
	}

	local($osum) = $bytes[$base + $hl + 1];
	$bytes[$base + $hl + 1] = 0;
	$hs2 = &dosum(0, $base + $hl, $cnt);
	$bytes[$base + $hl + 1] = $osum;

	if ($osum != $hs2) {
	printf " ICMP: (%x) %x != %x", $hs, $osum, $hs2;
	} else {
	print " ICMP: ok";
	}
	if ($base == 0) {
	$type = $bytes[$hl] >> 8;
	if ($type == 3 \|\| $type == 4 \|\| $type == 5 \|\|
	$type == 11 \|\| $type == 12) {
	&ipv4check($hl + 4);
	}
	}
	}

	while ($#ARGV >= 0) {
	open(I, "$ARGV[0]") \|\| die $!;
	print "--- $ARGV[0] ---\n";
	$multi = 0;
	while (<I>) {
	chop;
	s/#.*//g;

	#
	# If the first non-comment, non-empty line of input starts
	# with a '[', then allow the input to be a multi-line hex
	# string, otherwise it has to be all on one line.
	#
	if (/^\[/) {
	$multi=1;
	s/^\[[^]]*\]//g;

	}
	s/^ *//g;
	if (length == 0) {
	next if ($cnt == 0);
	&ipv4check(0);
	$cnt = 0;
	$multi = 0;
	next;
	}

	#
	# look for 16 bits, represented with leading 0's as required,
	# in hex.
	#
	s/\t/ /g;
	while (/^[0-9a-fA-F][0-9a-fA-F] [0-9a-fA-F][0-9a-fA-F] .*/) {
	s/^([0-9a-fA-F][0-9a-fA-F]) ([0-9a-fA-F][0-9a-fA-F]) (.*)/$1$2 $3/;
	}
	while (/.* [0-9a-fA-F][0-9a-fA-F] [0-9a-fA-F][0-9a-fA-F] .*/) {
	$b=$_;
	s/(.?) ([0-9a-fA-F][0-9a-fA-F]) ([0-9a-fA-F][0-9a-fA-F]) (.)/$1 $2$3 $4/g;
	}
	if (/.* [0-9a-fA-F][0-9a-fA-F] [0-9a-fA-F][0-9a-fA-F]/) {
	$b=$_;
	s/(.*?) ([0-9a-fA-F][0-9a-fA-F]) ([0-9a-fA-F][0-9a-fA-F])/$1 $2$3/g;
	}
	while (/^[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F].*/) {
	$x = $_;
	$x =~ s/([0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]).*/$1/;
	$x =~ s/ *//g;
	$y = hex $x;
	s/[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F] (.)/$1/;
	$bytes[$cnt] = $y;
	#print "bytes[$cnt] = $x\n";
	$cnt++;
	}

	#
	# Pick up stragler bytes.
	#
	if (/^[0-9a-fA-F][0-9a-fA-F]/) {
	$y = hex $_;
	$bytes[$cnt++] = $y * 256;
	}
	if ($multi == 0 && $cnt > 0) {
	&ipv4check(0);
	$cnt = 0;
	}
	}

	if ($cnt > 0) {
	&ipv4check(0);
	}
	close(I);
	shift(@ARGV);
	}