From 2d02ea94587bfb1be0a3d5c7b8b592f52dbcd124 Mon Sep 17 00:00:00 2001
From: Dobrica Pavlinusic <dpavlin@rot13.org>
Date: Fri, 18 Sep 2020 16:05:32 +0200
Subject: [PATCH] support requence, cleanup protocol parsing

dump binary packets in /dev/shm with DEBUG=1
---
 unpack.pl | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/unpack.pl b/unpack.pl
index 683e731..1e04e2d 100755
--- a/unpack.pl
+++ b/unpack.pl
@@ -75,6 +75,7 @@ sub modbus_crc16 {
 my $protocol;
 while(<DATA>) {
 	chomp;
+	next if m{^\s*$}; # skip empty lines
 	my @a = split(/\s*\t\s*/, $_,7);
 	my $id = hex( $a[0] );
 	my $pack_fmt = $a[2]; $pack_fmt =~ s/\s+.*$//;
@@ -91,16 +92,24 @@ while(<DATA>) {
 
 warn "## protocol = ",dump( $protocol ) if $debug;
 
+my $pkg_nr = 0;
 
 sub protocol_decode {
-	my ( $up_down, $raw ) = @_;
+	my ( $up_down, $hex ) = @_;
 
-warn "up/down: $up_down raw = ",dump($raw);
+warn "up/down: $up_down hex = ",dump($hex);
 
-my $bin = join('', map { chr(hex($_)) } split(/\s+/,$raw));
+my $bin = join('', map { chr(hex($_)) } split(/\s+/,$hex));
 
 warn "bin = ", dump($bin);
 
+if ( $debug ) {
+	open(my $dump, '>', "/dev/shm/zc.$pkg_nr.$up_down");
+	print $dump $bin;
+	close($dump);
+	$pkg_nr++;
+}
+
 my $cksum = substr($bin, -2, 2);
 
 if ( my $crc = modbus_crc16( substr($bin,0,-2) ) ) {
@@ -144,13 +153,21 @@ while ( $data ) {
 	warn "XXX data = $hex\n";
 
 	my $data_id = unpack( 'C', substr($data,0,1) );
-	my $data_id_desc = $protocol->{$data_id}->{description} || die "can't find description for data_id $data_id";
+	my $data_id_desc = $protocol->{$data_id}->{description};
+	if ( ! $data_id_desc ) {
+       		warn "ERROR: no description for data_id $data_id SKIPPING!";
+		$data = substr($data,1);
+		next;
+	}
 	my $pack_fmt = $protocol->{$data_id}->{pack_fmt} || die "can't find pack_fmt for data_id $data_id";
 
 	my $data_range;
 
 	if ( $data_id == 0x00 ) {
-		warn "FIXME seq number?";
+		# sequence number
+
+		$data_range = substr($data,2,4);
+		$data = substr($data,6);
 
 	} elsif ( $up_down eq 'down' && $function_code == 0x03 ) {
 		# type A
-- 
2.20.1