--- loncom/lonnet/perl/lonnet.pm	2007/04/11 21:37:20	1.868
+++ loncom/lonnet/perl/lonnet.pm	2007/04/11 22:52:03	1.869
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.868 2007/04/11 21:37:20 raeburn Exp $
+# $Id: lonnet.pm,v 1.869 2007/04/11 22:52:03 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -182,7 +182,7 @@ sub subreply {
 	$client=IO::Socket::UNIX->new(Peer    =>"$peerfile",
 				      Type    => SOCK_STREAM,
 				      Timeout => 10);
-	if($client) {
+	if ($client) {
 	    last;		# Connected!
 	} else {
 	    &create_connection(&hostname($server),$server);
@@ -7682,19 +7682,40 @@ sub goodbye {
 }
 
 sub get_dns {
-    my ($url,$func) = @_;
+    my ($url,$func,$ignore_cache) = @_;
+    if (!$ignore_cache) {
+	my ($content,$cached)=
+	    &Apache::lonnet::is_cached_new('dns',$url);
+	if ($cached) {
+	    &$func($content);
+	    return;
+	}
+    }
+
+    my %alldns;
     open(my $config,"<$perlvar{'lonTabDir'}/hosts.tab");
     foreach my $dns (<$config>) {
 	next if ($dns !~ /^\^(\S*)/x);
-	$dns = $1;
+	$alldns{$1} = 1;
+    }
+    while (%alldns) {
+	my ($dns) = keys(%alldns);
+	delete($alldns{$dns});
 	my $ua=new LWP::UserAgent;
 	my $request=new HTTP::Request('GET',"http://$dns$url");
 	my $response=$ua->request($request);
 	next if ($response->is_error());
 	my @content = split("\n",$response->content);
+	&Apache::lonnet::do_cache_new('dns',$url,\@content,30*24*60*60);
 	&$func(\@content);
+	return;
     }
     close($config);
+    &logthis("unable to contact DNS defaulting to on disk file\n");
+    open($config,"<$perlvar{'lonTabDir'}/dns_hosts.tab");
+    my @content = <$config>;
+    &$func(\@content);
+    return;
 }
 # ------------------------------------------------------------ Read domain file
 {
@@ -7724,7 +7745,8 @@ sub get_dns {
     }
 
     sub load_domain_tab {
-	&get_dns('/adm/dns/domain',\&parse_domain_tab);
+	my ($ignore_cache) = @_;
+	&get_dns('/adm/dns/domain',\&parse_domain_tab,$ignore_cache);
 	my $fh;
 	if (open($fh,"<".$perlvar{'lonTabDir'}.'/domain.tab')) {
 	    my @lines = <$fh>;
@@ -7781,7 +7803,8 @@ sub get_dns {
     }
 
     sub load_hosts_tab {
-	&get_dns('/adm/dns/hosts',\&parse_hosts_tab);
+	my ($ignore_cache) = @_;
+	&get_dns('/adm/dns/hosts',\&parse_hosts_tab,$ignore_cache);
 	open(my $config,"<$perlvar{'lonTabDir'}/hosts.tab");
 	my @config = <$config>;
 	&parse_hosts_tab(\@config);
@@ -7857,6 +7880,25 @@ sub get_dns {
     my %iphost;
     my %name_to_ip;
     my %lonid_to_ip;
+
+    my %valid_ip;
+    sub valid_ip {
+	my ($ip) = @_;
+	if (exists($iphost{$ip}) || exists($valid_ip{$ip})) {
+	    return 1;	
+	}
+	my $name = gethostbyip($ip);
+	my $lonid = &hostname($name);
+	if (defined($lonid)) {
+	    $valid_ip{$ip} = $lonid;
+	    return 1;
+	}
+	my %iphosts = &get_iphost();
+	if (ref($iphost{$ip})) {
+	    return 1;	
+	}
+    }
+
     sub get_hosts_from_ip {
 	my ($ip) = @_;
 	my %iphosts = &get_iphost();
@@ -7887,7 +7929,20 @@ sub get_dns {
     }
     
     sub get_iphost {
-	if (%iphost) { return %iphost; }
+	my ($ignore_cache) = @_;
+	if (!$ignore_cache) {
+	    if (%iphost) {
+		return %iphost;
+	    }
+	    my ($ip_info,$cached)=
+		&Apache::lonnet::is_cached_new('iphost','iphost');
+	    if ($cached) {
+		%iphost      = %{$ip_info->[0]};
+		%name_to_ip  = %{$ip_info->[1]};
+		%lonid_to_ip = %{$ip_info->[2]};
+		return %iphost;
+	    }
+	}
 	my %hostname = &all_hostnames();
 	foreach my $id (keys(%hostname)) {
 	    my $name=&hostname($id);
@@ -7906,6 +7961,10 @@ sub get_dns {
 	    $lonid_to_ip{$id} = $ip;
 	    push(@{$iphost{$ip}},$id);
 	}
+	&Apache::lonnet::do_cache_new('iphost','iphost',
+				      [\%iphost,\%name_to_ip,\%lonid_to_ip],
+				      24*60*60);
+
 	return %iphost;
     }
 }