Chain pinging and other minor things

6 files changed, 223 insertions, 43 deletions

diff --git a/Echolot/Chain.pm b/Echolot/Chain.pm
index 02494ae..14186a2 100644
--- a/Echolot/Chain.pm
+++ b/Echolot/Chain.pm
@@ -1,7 +1,7 @@
 package Echolot::Chain;
 
 # (c) 2002 Peter Palfrader <peter@palfrader.org>
-# $Id: Chain.pm,v 1.3 2003/02/15 11:43:41 weasel Exp $
+# $Id: Chain.pm,v 1.4 2003/02/16 03:06:51 weasel Exp $
 #
 
 =pod
@@ -105,7 +105,7 @@ sub remailer_supports_chaintype($$) {
 	my ($address, $type) = @_;
 
 	my %supports = map { $_ => 1} Echolot::Globals::get()->{'storage'}->get_types($address);
-	for my $type (@{Echolot::Config::get()->{'do_chainpings'}->{$type}}) {
+	for my $type (@{Echolot::Config::get()->{'which_chainpings'}->{$type}}) {
 		return $type if $supports{$type};
 	};
 	return 0;
@@ -145,7 +145,7 @@ sub send_pings($;$$) {
 			$which1 eq $addr1 ||
 			$which1 eq '');
 
-		for my $chaintype (keys %{Echolot::Config::get()->{'do_chainpings'}}) {
+		for my $chaintype (keys %{Echolot::Config::get()->{'which_chainpings'}}) {
 			my $type1 = remailer_supports_chaintype($addr1, $chaintype);;
 			next unless $type1;
 			my $key1 = get_latest_key($addr1, $type1);
diff --git a/Echolot/Config.pm b/Echolot/Config.pm
index 50d7ca7..db20904 100644
--- a/Echolot/Config.pm
+++ b/Echolot/Config.pm
@@ -1,7 +1,7 @@
 package Echolot::Config;
 
 # (c) 2002 Peter Palfrader <peter@palfrader.org>
-# $Id: Config.pm,v 1.49 2003/02/15 11:43:41 weasel Exp $
+# $Id: Config.pm,v 1.50 2003/02/16 03:06:51 weasel Exp $
 #
 
 =pod
@@ -68,6 +68,8 @@ sub init($) {
 
 		# Magic Numbers
 		hash_len                    => 8,
+		stats_days                  => 12,
+		seconds_per_day             => 24 * 60 * 60,
 
 		# New Remailers
 		fetch_new                   => 1,
@@ -99,6 +101,10 @@ sub init($) {
 
 		chainpinger_interval        => 5*60, # send out pings every 5 minutes
 		chainping_every_nth_time    => 810,  # send out pings to the same chain every 810 calls, i.e. every 3 days
+		chainping_period            => 10*24*60*60, # 10 days
+		chainping_fudge             => 0.7, # if less than 0.7 * rel1 * rel2 make it, the chain is really broken
+		chainping_grace             => 1.5, # don't count pings sent no longer than 1.5 * (lat1 + lat2) ago
+		chainping_update            => 300, # chain stats should never be older than 300 seconds
 
 		addresses_default_ttl       => 5, # getkeyconf seconds (days)
 		check_resurrection_ttl      => 8, # check_resurrection seconds (weeks)
@@ -131,14 +137,14 @@ sub init($) {
 		commands_file               => 'commands.txt',
 		pidfile                     => 'pingd.pid',
 
-		'save-errormails'           => 0,
+		save_errormails             => 0,
 		write_meta_files            => 1,
 		meta_extension              => '.meta',
 
 		storage                     => {
-			backend                 	=> 'File',
-			File                    	=> {
-				basedir             		=> 'data'
+			backend                 => 'File',
+			File                    => {
+				basedir             => 'data'
 			}
 		},
 
@@ -154,8 +160,8 @@ sub init($) {
 			'cpunk-clear' => 1,
 			'mix' => 1
 		},
-		# ping types
-		do_chainpings => {
+		do_chainpings => 1,
+		which_chainpings => {
 			'cpunk' => [ qw{cpunk-dsa cpunk-rsa cpunk-clear} ],
 			'mix' => [ qw{mix} ]
 		},
diff --git a/Echolot/Mailin.pm b/Echolot/Mailin.pm
index 266ccff..41d4863 100644
--- a/Echolot/Mailin.pm
+++ b/Echolot/Mailin.pm
@@ -1,7 +1,7 @@
 package Echolot::Mailin;
 
 # (c) 2002 Peter Palfrader <peter@palfrader.org>
-# $Id: Mailin.pm,v 1.13 2003/02/15 11:43:41 weasel Exp $
+# $Id: Mailin.pm,v 1.14 2003/02/16 03:06:51 weasel Exp $
 #
 
 =pod
@@ -214,7 +214,7 @@ sub process() {
 	Echolot::Globals::get()->{'storage'}->delay_commit();
 	for my $mail (@$mails) {
 		unless (handle($mail)) {
-			if (Echolot::Config::get()->{'save-errormails'}) {
+			if (Echolot::Config::get()->{'save_errormails'}) {
 				Echolot::Log::info("Saving mail with unknown destination (probably a bounce) to mail-errordir.");
 				my $name = make_sane_name();
 				storemail($mailerrordir, $mail) or
diff --git a/Echolot/Stats.pm b/Echolot/Stats.pm
index 39eef51..c3a21b4 100644
--- a/Echolot/Stats.pm
+++ b/Echolot/Stats.pm
@@ -1,7 +1,7 @@
 package Echolot::Stats;
 
 # (c) 2002 Peter Palfrader <peter@palfrader.org>
-# $Id: Stats.pm,v 1.39 2003/02/15 11:43:41 weasel Exp $
+# $Id: Stats.pm,v 1.40 2003/02/16 03:06:51 weasel Exp $
 #
 
 =pod
@@ -18,8 +18,6 @@ and keyrings.
 =cut
 
 use strict;
-use constant DAYS => 12;
-use constant SECS_PER_DAY => 24 * 60 * 60;
 use English;
 use Echolot::Log;
 
@@ -29,6 +27,12 @@ my $NORMAL = new Statistics::Distrib::Normal;
 $NORMAL->mu(0);
 $NORMAL->sigma(1);
 
+my $STATS_DAYS;
+my $SECONDS_PER_DAY;
+
+my %LAST_BROKENCHAIN_RUN;
+my %BROKEN_CHAINS;
+
 sub make_date() {
 	my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday) = gmtime();
 	sprintf("%s %02d %s %4d %02d:%02d:%02d GMT",
@@ -69,9 +73,9 @@ sub make_min_hr($$) {
 sub build_list1_latencystr($) {
 	my ($lat) = @_;
 
-	my $str = '?' x DAYS;
-	for my $day (0 .. DAYS - 1) {
-		substr($str, DAYS - 1 - $day, 1) = 
+	my $str = '?' x $STATS_DAYS;
+	for my $day (0 .. $STATS_DAYS - 1) {
+		substr($str, $STATS_DAYS - 1 - $day, 1) = 
 			(defined $lat->[$day]) ?
 			 ($lat->[$day] <    300 ? '#' :
 			  ($lat->[$day] <   3600 ? '*' :
@@ -88,9 +92,9 @@ sub build_list1_latencystr($) {
 sub build_list2_latencystr($) {
 	my ($lat) = @_;
 
-	my $str = '?' x DAYS;
-	for my $day (0 .. DAYS - 1) {
-		substr($str, DAYS - 1 - $day, 1) = 
+	my $str = '?' x $STATS_DAYS;
+	for my $day (0 .. $STATS_DAYS - 1) {
+		substr($str, $STATS_DAYS - 1 - $day, 1) = 
 			(defined $lat->[$day]) ?
 			 ($lat->[$day] <    20*60 ? '0' :
 			  ($lat->[$day] <   1*3600 ? '1' :
@@ -119,9 +123,9 @@ sub build_list2_latencystr($) {
 sub build_list2_reliabilitystr($) {
 	my ($rel) = @_;
 
-	my $str = '?' x DAYS;
-	for my $day (0 .. DAYS - 1) {
-		substr($str, DAYS - 1 - $day, 1) =
+	my $str = '?' x $STATS_DAYS;
+	for my $day (0 .. $STATS_DAYS - 1) {
+		substr($str, $STATS_DAYS - 1 - $day, 1) =
 			(defined $rel->[$day]) ?
 				(($rel->[$day] >= 0.9999) ?
 				#(($rel->[$day] == 1) ?
@@ -198,8 +202,8 @@ sub calculate($$) {
 		next unless Echolot::Globals::get()->{'storage'}->has_type($addr, $type);
 		my @keys = Echolot::Globals::get()->{'storage'}->get_keys($addr, $type);
 		for my $key (@keys) {
-			push @out,  grep {$_      > $now - DAYS * SECS_PER_DAY} Echolot::Globals::get()->{'storage'}->get_pings($addr, $type, $key, 'out');
-			push @done, grep {$_->[0] > $now - DAYS * SECS_PER_DAY} Echolot::Globals::get()->{'storage'}->get_pings($addr, $type, $key, 'done');
+			push @out,  grep {$_      > $now - $STATS_DAYS * $SECONDS_PER_DAY} Echolot::Globals::get()->{'storage'}->get_pings($addr, $type, $key, 'out');
+			push @done, grep {$_->[0] > $now - $STATS_DAYS * $SECONDS_PER_DAY} Echolot::Globals::get()->{'storage'}->get_pings($addr, $type, $key, 'done');
 		};
 	};
 
@@ -210,13 +214,13 @@ sub calculate($$) {
 	my @received;
 	my @sent;
 	for my $done (@done) {
-		$latency += $done->[1];   $latency [int(($now - $done->[0]) / SECS_PER_DAY)] += $done->[1];
-		$sent ++;                 $sent    [int(($now - $done->[0]) / SECS_PER_DAY)] ++;
-		$received ++;             $received[int(($now - $done->[0]) / SECS_PER_DAY)] ++;
+		$latency += $done->[1];   $latency [int(($now - $done->[0]) / $SECONDS_PER_DAY)] += $done->[1];
+		$sent ++;                 $sent    [int(($now - $done->[0]) / $SECONDS_PER_DAY)] ++;
+		$received ++;             $received[int(($now - $done->[0]) / $SECONDS_PER_DAY)] ++;
 	};
 	$latency /= (scalar @done) if (scalar @done);
 	$latency = undef unless (scalar @done);
-	for ( 0 .. DAYS - 1 ) {
+	for ( 0 .. $STATS_DAYS - 1 ) {
 		$latency[$_] /= $received[$_] if ($received[$_]);
 	};
 
@@ -232,12 +236,12 @@ sub calculate($$) {
 				$NORMAL->utp( map { ($now - $_ - $latency) / $deviation } @out ) :
 				map { 0 } @out;
 		for (my $i=0; $i < scalar @out; $i++) {
-			$sent ++;            $sent    [int(($now - $out[$i]) / SECS_PER_DAY)] ++;
-			$received += $p[$i]; $received[int(($now - $out[$i]) / SECS_PER_DAY)] += $p[$i];
+			$sent ++;            $sent    [int(($now - $out[$i]) / $SECONDS_PER_DAY)] ++;
+			$received += $p[$i]; $received[int(($now - $out[$i]) / $SECONDS_PER_DAY)] += $p[$i];
 		};
 	};
 	$received /= $sent if ($sent);
-	for ( 0 .. DAYS - 1 ) {
+	for ( 0 .. $STATS_DAYS - 1 ) {
 		$received[$_] /= $sent[$_] if ($sent[$_]);
 	};
 
@@ -472,6 +476,83 @@ sub build_rems($) {
 	return \@rems;
 };
 
+sub find_broken_chains($$$) {
+	my ($chaintype, $rems, $manual) = @_;
+
+	if (!defined $LAST_BROKENCHAIN_RUN{$chaintype} ||
+	    $LAST_BROKENCHAIN_RUN{$chaintype} < time() - Echolot::Config::get()->{'chainping_update'} ||
+	    ! defined $BROKEN_CHAINS{$chaintype} ) {
+		Echolot::Log::debug ("Broken Chains $chaintype need generating."),
+		$LAST_BROKENCHAIN_RUN{$chaintype} = time();
+
+		my $pings = Echolot::Globals::get()->{'storage'}->get_chainpings($chaintype);
+
+		my %remailers = map { $_->{'address'} => $_ } @$rems;
+
+		my $stats;
+		my %received;
+		my @broken_chains;
+		for my $status (qw{done out}) {
+			my $status_done = $status eq 'done';
+			my $status_out = $status eq 'out';
+			for my $ping (@{$pings->{$status}}) {
+				my $addr1 = $ping->{'addr1'};
+				my $addr2 = $ping->{'addr2'};
+				my $sent  = $ping->{'sent'};
+				next if $sent < (time() - Echolot::Config::get()->{'chainping_period'});
+				next unless defined $remailers{$addr1};
+				next unless defined $remailers{$addr2};
+
+				if ($status_done) {
+					$received{$addr1.':'.$addr2.':'.$sent} = 1;
+				};
+				if ($status_out && !defined $received{$addr1.':'.$addr2.':'.$sent}) {
+					my $theoretical_lat = $remailers{$addr1}->{'stats'}->{'avr_latency'} +
+							      $remailers{$addr2}->{'stats'}->{'avr_latency'};
+					$theoretical_lat = 0 unless defined $theoretical_lat;
+					my $latency = time() - $ping->{'sent'};
+					# print ("lat helps $latency $theoretical_lat\n"), 
+					next if ($latency < $theoretical_lat * Echolot::Config::get()->{'chainping_grace'});
+				};
+
+				# print "Having $addr1 $addr2 $status at $sent\n";
+				$stats->{$addr1}->{$addr2}->{$status}++;
+			};
+		};
+		# require Data::Dumper;
+		# print Data::Dumper->Dump([$stats]);
+		for my $addr1 (keys %$stats) {
+			for my $addr2 (keys %{$stats->{$addr1}}) {
+				my $theoretical_rel = $remailers{$addr1}->{'stats'}->{'avr_reliability'} *
+						      $remailers{$addr2}->{'stats'}->{'avr_reliability'};
+				($stats->{$addr1}->{$addr2}->{'out'} != 0) or
+					Echolot::Log::debug("Should not devide through zero (".
+						$stats->{$addr1}->{$addr2}->{'done'}."/".
+						$stats->{$addr1}->{$addr2}->{'out'}.
+						") for $addr1, $addr2."),
+					next;
+				my $real_rel = $stats->{$addr1}->{$addr2}->{'done'} /
+					       $stats->{$addr1}->{$addr2}->{'out'};
+				# print "$addr1 $addr2 $stats->{$addr1}->{$addr2}->{'done'}/$stats->{$addr1}->{$addr2}->{'out'}".
+				#       " == $real_rel ($theoretical_rel)\n";
+				next if ($real_rel > $theoretical_rel * Echolot::Config::get()->{'chainping_fudge'});
+				my $nick1 = $remailers{$addr1}->{'nick'};
+				my $nick2 = $remailers{$addr2}->{'nick'};
+				push @broken_chains, "($nick1 $nick2)\n";
+			};
+		};
+		$BROKEN_CHAINS{$chaintype} = \@broken_chains;
+	} else {
+		Echolot::Log::debug ("Broken Chains $chaintype are up to date."),
+	};
+
+	my @result = defined $manual ? (split /\n/, $manual) : ();
+	push @result, @{ $BROKEN_CHAINS{$chaintype} };
+	my %unique;
+	@result = grep { ! $unique{$_}++; } @result;
+	return join "\n", @result;
+};
+
 sub build_lists() {
 
 	my $clist;
@@ -486,7 +567,16 @@ sub build_lists() {
 	my $broken2 = read_file( Echolot::Config::get()->{'broken2'}, 1);
 	my $sameop = read_file( Echolot::Config::get()->{'sameop'}, 1);
 
-	$rems = build_rems(['mix']);
+
+	my $mixrems = build_rems(['mix']);
+	my $cpunkrems = build_rems(['cpunk-rsa', 'cpunk-dsa', 'cpunk-clear']);
+	if (Echolot::Config::get()->{'do_chainpings'}) {
+		$broken1 = find_broken_chains('cpunk', $cpunkrems, $broken1);
+		$broken2 = find_broken_chains('mix', $mixrems, $broken2);
+	};
+
+	$rems = $mixrems;
+	$mixrems = undef;
 	@$pubrems = grep { $_->{'showit'} } @$rems;
 	build_mlist1( $rems, $broken1, $broken2, $sameop, Echolot::Config::get()->{'private_resultdir'}.'/'.'mlist', 'mlist');
 	build_list2( $rems, 2, $broken1, $broken2, $sameop, Echolot::Config::get()->{'private_resultdir'}.'/'.'mlist2', 'mlist2');
@@ -500,7 +590,8 @@ sub build_lists() {
 		$pubclist->{'mix'} = $pubrems; $pubrems = undef;
 	};
 
-	$rems = build_rems(['cpunk-rsa', 'cpunk-dsa', 'cpunk-clear']);
+	$rems = $cpunkrems;
+	$cpunkrems = undef;
 	@$pubrems = grep { $_->{'showit'} } @$rems;
 	build_rlist1( $rems, $broken1, $broken2, $sameop, Echolot::Config::get()->{'private_resultdir'}.'/'.'rlist', 'rlist');
 	build_list2( $rems, 1, $broken1, $broken2, $sameop,  Echolot::Config::get()->{'private_resultdir'}.'/'.'rlist2', 'rlist2');
@@ -805,6 +896,8 @@ sub build_pgpring() {
 };
 
 sub build_stats() {
+	$STATS_DAYS = Echolot::Config::get()->{'stats_days'};
+	$SECONDS_PER_DAY = Echolot::Config::get()->{'seconds_per_day'};
 	build_lists();
 };
 sub build_keys() {
diff --git a/Echolot/Storage/File.pm b/Echolot/Storage/File.pm
index c22b325..9309a03 100644
--- a/Echolot/Storage/File.pm
+++ b/Echolot/Storage/File.pm
@@ -1,7 +1,7 @@
 package Echolot::Storage::File;
 
 # (c) 2002 Peter Palfrader <peter@palfrader.org>
-# $Id: File.pm,v 1.49 2003/02/15 11:43:41 weasel Exp $
+# $Id: File.pm,v 1.50 2003/02/16 03:06:51 weasel Exp $
 #
 
 =pod
@@ -639,7 +639,7 @@ Returns 1.
 sub chainpingdata_open($) {
 	my ($self) = @_;
 
-	for my $type ( keys %{Echolot::Config::get()->{'do_chainpings'}} ) {
+	for my $type ( keys %{Echolot::Config::get()->{'which_chainpings'}} ) {
 		$self->chainpingdata_open_one($type);
 	};
 
@@ -715,6 +715,86 @@ sub chainpingdata_close($) {
 
 
 
+=item $storage->B<get_chainpings>( I<$chaintype> )
+
+Return chainping data for I<$chaintype>.
+
+The result is a reference to a hash having two entries: out and done.
+
+Each of them is a reference to an array of single pings.  Each ping is a hash
+reference with the hash having the keys B<sent>, B<addr1>, B<type1>, B<key1>,
+B<addr2>, B<type2>, B<key2>, and in case of received pings B<lat>.
+
+Out currently includes all sent pings - also those that allready arrived.
+This is different from the get_pings() function above.
+
+Returns undef on error.
+
+=cut
+sub get_chainpings($$) {
+	my ($self, $chaintype) = @_;
+
+	my $fh = $self->get_chainping_fh($chaintype, 'out') or
+		Echolot::Log::warn ("assigned filehandle for $chaintype out chainpings."),
+		return undef;
+	seek($fh, 0, SEEK_SET) or
+		Echolot::Log::warn("Cannot seek to start of $chaintype out chainpings $!."),
+		return undef;
+	my @out =
+		map {
+			chomp;
+			my @a = split;
+			{	sent  => $a[0],
+				addr1 => $a[1],
+				type1 => $a[2],
+				key1  => $a[3],
+				addr2 => $a[4],
+				type2 => $a[5],
+				key2  => $a[6]
+			}
+		} <$fh>;
+	my %sent = map {
+		my $a = $_;
+		my $key = join (' ', map ({ $a->{$_} } qw{sent addr1 type1 key1 addr2 type2 key2}));
+		$key => 1
+	} @out;
+
+	$fh = $self->get_chainping_fh($chaintype, 'done') or
+		Echolot::Log::warn ("assigned filehandle for $chaintype done chainpings."),
+		return undef;
+	seek($fh, 0, SEEK_SET) or
+		Echolot::Log::warn("Cannot seek to start of $chaintype done chainpings $!."),
+		return undef;
+	my @done =
+		grep {
+			# Only list things that actually got sent - and only once
+			my $a = $_;
+			my $key = join (' ', map ({ $a->{$_} } qw{sent addr1 type1 key1 addr2 type2 key2}));
+			my $exists = exists $sent{$key};
+			delete $sent{$key};
+			$exists
+		}
+		map {
+			chomp;
+			my @a = split;
+			{	sent  => $a[0],
+				addr1 => $a[1],
+				type1 => $a[2],
+				key1  => $a[3],
+				addr2 => $a[4],
+				type2 => $a[5],
+				key2  => $a[6],
+				lat   => $a[7]
+			}
+		} <$fh>;
+
+	return {
+		out => \@out,
+		done => \@done
+	};
+};
+
+
 =item $storage->B<register_chainpingout>( I<$chaintype>, I<$addr1>, I<$type1>, I<$key1>, I<$addr2>, I<$type2>, I<$key2>, I<$sent_time> >
 
 Register a chain ping of type I<$chaintype> sent through I<$addr1> (I<$type1>, I<$key1>)
@@ -761,7 +841,7 @@ sub register_chainpingdone($$$$$$$$$$) {
 	seek($fh, 0, SEEK_END) or
 		Echolot::Log::warn("Cannot seek to end of $chaintype/done pings: $!."),
 		return undef;
-	print($fh join(' ', $sent_time, $latency, $addr1, $type1, $key1, $addr2, $type2, $key2)."\n") or
+	print($fh join(' ', $sent_time, $addr1, $type1, $key1, $addr2, $type2, $key2, $latency)."\n") or
 		Echolot::Log::warn("Error when writing to $chaintype/done pings: $!."),
 		return undef;
 	$fh->flush();
diff --git a/pingd b/pingd
index 565956f..ce231a0 100755
--- a/pingd
+++ b/pingd
@@ -2,8 +2,8 @@
 
 $| = 1;
 
-# (c) 2002 Peter Palfrader <peter@palfrader.org>
-# $Id: pingd,v 1.95 2003/02/14 05:12:37 weasel Exp $
+# (c) 2002, 2003 Peter Palfrader <peter@palfrader.org>
+# $Id: pingd,v 1.96 2003/02/16 03:06:51 weasel Exp $
 #
 
 =pod
@@ -502,7 +502,8 @@ sub daemon_run($) {
 
 	$scheduler->add('processmail'         , Echolot::Config::get()->{'processmail'}          , 0, \&Echolot::Mailin::process );
 	$scheduler->add('ping'                , Echolot::Config::get()->{'pinger_interval'}      , 0, \&Echolot::Pinger::send_pings );
-	$scheduler->add('chainping'           , Echolot::Config::get()->{'chainpinger_interval'} , 0, \&Echolot::Chain::send_pings );
+	$scheduler->add('chainping'           , Echolot::Config::get()->{'chainpinger_interval'} , 0, \&Echolot::Chain::send_pings )
+		if Echolot::Config::get()->{'do_chainpings'};
 	$scheduler->add('buildstats'          , Echolot::Config::get()->{'buildstats'}           , 0, \&Echolot::Stats::build_stats );
 	$scheduler->add('buildkeys'           , Echolot::Config::get()->{'buildkeys'}            , 0, \&Echolot::Stats::build_keys );
 	$scheduler->add('buildthesaurus'      , Echolot::Config::get()->{'buildthesaurus'}       , 0, \&Echolot::Thesaurus::build_thesaurus );
@@ -621,7 +622,7 @@ if (!GetOptions (
 if ($params->{'help'}) {
     print ("Usage: $PROGRAM_NAME [options] command\n");
     print ("See man pingd or perldoc pingd for more info.\n");
-    print ("echolot $VERSION - (c) 2002 Peter Palfrader <peter\@palfrader.org>\n");
+    print ("echolot $VERSION - (c) 2002, 2003 Peter Palfrader <peter\@palfrader.org>\n");
     print ("http://savannah.gnu.org/projects/echolot/\n");
 	print ("\n");
 	print ("Commands:\n");
@@ -644,7 +645,7 @@ if ($params->{'help'}) {
 };
 if ($params->{'version'}) {
     print ("echolot $VERSION\n");
-    print ("(c) 2002 Peter Palfrader <peter\@palfrader.org>\n");
+    print ("(c) 2002, 2003 Peter Palfrader <peter\@palfrader.org>\n");
     print ("http://savannah.gnu.org/projects/echolot/\n");
     exit 0;
 };