#!/usr/local/bin/perl -w

use strict;
use Getopt::Std;

use vars qw($opt_q);

# VH   size  id  flag TL P sum  source-IP
# 4500 0072 bdfd 4000 3f06 f8a5 c0a8 0202
#
# dest-IP   s-pt d-pt sequence# ack-numbr
#
# c0a8 0190 0438 0406 3470 7a31 000a 04cd
# HFlg win  sum  urg
# 5018 4470 cde2 0000 1080 fe00 0011 0042
#
# 0010 8100 6966 0000 0000 0000 0000 0000

my $address = 0;

sub nz($;$) {
	return defined($_[0]) ? $_[0] : (defined($_[1]) ? $_[1] : "");
}

sub iskanjiout($$$) {
	my ($a, $b, $c) = @_;
	return nz($a, 0) == 0x1b && nz($b, 0) == 0x28 && (nz($c, 0) == 0x42 || nz($c, 0) == 0x4a);
}

sub iskanjiin($$$) {
	my ($a, $b, $c) = @_;
	return nz($a, 0) == 0x1b && nz($b, 0) == 0x24 && nz($c, 0) == 0x42;
}

sub print_data($) {
	my ($s) = @_;
	my @v = unpack("C*", $s);
	my $total = $#v + 1;
	my $i;
	my $inkanji = 0;
	for ($i = 0; $i < $total; $i++) {
		my $c = $v[$i];
		if ($c == 0x0d) {
		}
		elsif ($inkanji && iskanjiout($c, $v[$i + 1], $v[$i + 2])) {
			print "\x1b";
			$inkanji = 0;
		}
		elsif (iskanjiin($c, $v[$i + 1], $v[$i + 2])) {
			my $match = 0;
			my $j;
			for ($j = $i; !$match && $j < $total - 2; $j++) {
				$match = iskanjiout($v[$j], $v[$j + 1], $v[$j + 2]);
			}
			if ($match) {
				print "\x1b";
				$inkanji = 1;
			}
			else {
				print "^[";
			}
		}
		elsif ($c == 0x0a) {
		}
		elsif ($c >= 0x20 && $c < 0x7f) {
			printf("%c", $c);
		}
		else {
			print ".";
		}
	}
	if ($total > 0) {
		printf("\n");
	}
}

sub tcpdata(@) {
	my (@v) = @_;
	my $i;
	my $s = "";
	#printf(">> %s\n", $ss);
	#for ($i = 0; $i <= $#v; $i++) {
	#	printf(" %02x", $v[$i]);
	#}
	my $ver = ($v[0] >> 4) & 0xf;
	if ($ver == 4) {
		my $ip_hlen = ($v[0] & 0xf) * 4;
		my $ip_total = $v[2] * 256 + $v[3];
		my $proto = $v[9];
		if ($proto == 6) { # tcp
			# sport(2) dport(2) seq(4) ack(4) HFlg(2) win(2) cksum(2) urg(2)
			my $tcp_hlen = (($v[$ip_hlen + 12] >> 4) & 0xf) * 4;
			my $tcp_data_top = $ip_hlen + $tcp_hlen;
			#printf("tcp_hlen=$tcp_hlen tcp_data_top=$tcp_data_top ip_total=$ip_total\n");
			if ($ip_total > $#v + 1) {
				$ip_total = $#v + 1;
			}
			if ($tcp_data_top < $ip_total) {
				splice(@v, 0, $tcp_data_top);
				$s = pack("C*", @v);
			}
		}
	}
	return $s;
}


sub view($$) {
	my ($hdr, $ss) = @_;
	my @v = split(/ /, $ss);
	#printf(">> %s\n", $ss);
	my $i;
	for ($i = 0; $i <= $#v; $i++) {
		$v[$i] = hex($v[$i]);
	}
	my $ver = ($v[0] >> 4) & 0xf;
	if ($ver != 4 && $v[12] == 0x08 && $v[13] == 0x00 && (($v[14] >> 4) & 0xf) == 4) {
		splice(@v, 0, 14);
		$ver = ($v[0] >> 4) & 0xf;
	}
	if ($ver == 4) {
		my $ip_hlen = ($v[0] & 0xf) * 4;
		my $ip_total = $v[2] * 256 + $v[3];
		my $proto = $v[9];
		if ($proto == 6) { # tcp
			# sport(2) dport(2) seq(4) ack(4) HFlg(2) win(2) cksum(2) urg(2)
			my $tcp_sport = ($v[$ip_hlen + 0] << 8) | $v[$ip_hlen + 1];
			my $tcp_dport = ($v[$ip_hlen + 2] << 8) | $v[$ip_hlen + 3];
			my $tcp_hlen = (($v[$ip_hlen + 12] >> 4) & 0xf) * 4;
			my $tcp_data_top = $ip_hlen + $tcp_hlen;
			my $s = tcpdata(@v);
			my @line = split(/\n/, $s);
			for ($i = 0; $i < $#line + 1; $i++) {
				if (!$opt_q || $line[$i] =~ /^(HELO|EHLO|MAIL|RCPT|DATA|QUIT|[0-9][0-9][0-9][- ])/i) {
					if ($hdr ne "") {
						printf("%s\n", $hdr);
						$hdr = "";
					}
					printf($tcp_dport == 25 ? "<<< " : ">>> ");
					print_data($line[$i]);
				}
			}
			if (!$opt_q && $hdr ne "") {
				printf("%s\n", $hdr);
			}
		}
		elsif ($proto == 17) { # udp
			# sport(2) dport(2) plen(2) cksum(2)
			#print "UDP> ", $ss, "\n";
		}
		elsif ($proto == 1) { # icmp
			#print "ICMP> ", $ss, "\n";
		}
	}
	else {
		#print "?> ", $ss, "\n";
	}
}

sub addhex($$) {
	my ($dst, $src) = @_;
	$src =~ s/ *$//;
	$src =~ s/([0-9A-Fa-f][0-9A-Fa-f])([0-9A-Fa-f][0-9A-Fa-f])/$1 $2/g;
	if ($dst ne "") {
		$dst .= " " . $src;
	}
	else {
		$dst = $src;
	}
	return $dst;
}

sub tcpdumpview() {
	my $lbuf;
	my $xbuf = "";
	my $mbuf = "";
	while ($lbuf = <>) {
		chomp($lbuf);
		#printf(">>>>[$lbuf]\n");
		if ($lbuf =~ /^[0-9][0-9]:/) {
			$address = 0;
			if ($xbuf ne "") {
				view($mbuf, $xbuf);
			}
			$xbuf = "";
			$mbuf = $lbuf;
		}
		if ($lbuf =~ /^[\t ]*0x/) {
			$lbuf =~ s/^[\t ]*0x[0-9A-Fa-f]+:?[\t ]+//;
			$lbuf =~ s/\t.*$//;
			$lbuf =~ s/  .*$//;
			$xbuf = addhex($xbuf, $lbuf);
		}
		elsif ($lbuf =~ /^\t/) {
			$lbuf =~ s/^[\t ]*//;
			$xbuf = addhex($xbuf, $lbuf);
		}
		else {
			# print $lbuf, "\n";
		}
	}
	if ($xbuf ne "") {
		view($mbuf, $xbuf);
	}
}

sub main() {
	getopts('q');
	tcpdumpview();
	return 0;
}

exit main();