status.pl

#!/usr/bin/perl

use Digest::MD5;
use Digest::HMAC;
use Crypt::RC4::XS;
use MIME::Base64;
use IO::Socket::INET;
use Config::IniFiles;
use Getopt::Long;


#
# Command line arguments:
#

my $help = '';
my $retrieve = '';

GetOptions (
	'help|h' => \$help,
	'retrieve|r' => \$retrieve );

if ($help) {
	print STDOUT
		"Usage: $0 [options] [msgcode]\n",
		"\n",
		"Get message status from server (default) or car (retrieve).\n",
		"Message code defaults to 'S'.\n",
		"\n",
		"Options:\n",
		" --help|-h       show this help\n",
		" --retrieve|-r   retrieve update from car module\n",
		"\n";
	exit;
}

my $cmd_code = $ARGV[0];

if (!$cmd_code) {
  # Default: "S"tatus message
  $cmd_code = "S";
}


#
# Read configuration
#

my $config = Config::IniFiles->new(-file => 'ovms_client.conf');

my $vehicle_id       = $config->val('client','vehicle_id','TESTCAR');
my $server_password  = $config->val('client','server_password','NETPASS');
my $module_password  = $config->val('client','module_password','OVMS');

my $server_ip        = $config->val('client','server_ip','54.197.255.127');


#####
##### CONNECT
#####

my $sock = IO::Socket::INET->new(PeerAddr => $server_ip,
                                 PeerPort => '6867',
                                 Proto    => 'tcp');

#####
##### REGISTER
#####

my $b64tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

rand;
my $client_token;
foreach (0 .. 21)
  { $client_token .= substr($b64tab,rand(64),1); }

my $client_hmac = Digest::HMAC->new($server_password, "Digest::MD5");
$client_hmac->add($client_token);
my $client_digest = $client_hmac->b64digest();

my $skipcnt;
if ($retrieve)
  {
  # Register as active client (type "A"):
  print $sock "MP-A 0 $client_token $client_digest $vehicle_id\r\n";
  $skipcnt = 1; # skip server status, wait for car status
  }
else
  {
  # Register as batch client (type "B"):
  print $sock "MP-B 0 $client_token $client_digest $vehicle_id\r\n";
  $skipcnt = 0; # use server status
  }

my $line = <$sock>;
chop $line;
chop $line;
my ($welcome,$crypt,$server_token,$server_digest) = split /\s+/,$line;

my $d_server_digest = decode_base64($server_digest);
my $client_hmac = Digest::HMAC->new($server_password, "Digest::MD5");
$client_hmac->add($server_token);
if ($client_hmac->digest() ne $d_server_digest)
  {
  print STDERR "  Client detects server digest is invalid - aborting\n";
  exit(1);
  }

$client_hmac = Digest::HMAC->new($server_password, "Digest::MD5");
$client_hmac->add($server_token);
$client_hmac->add($client_token);
my $client_key = $client_hmac->digest;

my $txcipher = Crypt::RC4::XS->new($client_key);
$txcipher->RC4(chr(0) x 1024); # Prime the cipher
my $rxcipher = Crypt::RC4::XS->new($client_key);
$rxcipher->RC4(chr(0) x 1024); # Prime the cipher


##### 
##### READ RESPONSE
##### 

my $ptoken = "";
my $pdigest = "";
my $data = "";
my $discardcnt = 0;

while(1)
{
	# Timeout socket reads after 10 seconds:
	eval {
			local $SIG{ALRM} = sub { die "Timed Out" };
			alarm 10;
			$data = <$sock>;
			alarm 0;
		};
		if ($@ and $@ =~ /Timed Out/) {
			print STDERR "No more results, exit.\n";
			exit;
		}

	chop $data; chop $data;
	my $decoded = $rxcipher->RC4(decode_base64($data));

	if ($decoded =~ /^MP-0 ET(.+)/) {
		$ptoken = $1;
		my $paranoid_hmac = Digest::HMAC->new($module_password, "Digest::MD5");
		$paranoid_hmac->add($ptoken);
		$pdigest = $paranoid_hmac->digest;
		# discard:
		$decoded = "";
	}
	elsif ($decoded =~ /^MP-0 EM(.)(.*)/) {
		my ($code,$data) = ($1,$2);
		my $pmcipher = Crypt::RC4::XS->new($pdigest);
		$pmcipher->RC4(chr(0) x 1024); # Prime the cipher
		$decoded = $pmcipher->RC4(decode_base64($data));
		# reformat as std msg:
		$decoded = "MP-0 ".$code.$decoded;
	}
	
	if ($decoded =~ /^MP-0 $cmd_code/) {
		if ($skipcnt eq 0) {
			print STDOUT $decoded,"\n";
			exit;
		} else {
			$skipcnt--;
		}
	}
	else {
		# exit if more than 25 other msgs received in series (assuming timeout):
		$discardcnt++;
		if ($discardcnt > 25) {
			print STDERR "No more results, exit.\n";
			exit;
		}
	}
}