--- loncom/lonnet/perl/londns.pm	2013/09/02 14:40:18	1.3
+++ loncom/lonnet/perl/londns.pm	2021/06/06 23:14:18	1.7
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # A debugging harness.
 #
-# $Id: londns.pm,v 1.3 2013/09/02 14:40:18 raeburn Exp $
+# $Id: londns.pm,v 1.7 2021/06/06 23:14:18 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,31 +31,48 @@ package Apache::londns;
 
 use strict;
 use LONCAPA;
-use Apache::Constants qw(:common :http);
+use Apache::Constants qw(:common :http :remotehost);
 use Apache::lonnet;
 
 sub serve_file {
-    my ($r,$file,$type)=@_;
-    open(my $config,"<$Apache::lonnet::perlvar{'lonTabDir'}/$file");
-    my $file = join('',<$config>);
-    $r->content_type($type);
-    $r->send_http_header;
-    return OK if $r->header_only;
-    $r->print($file);
-    return OK;
+    my ($r,$dir,$file,$type)=@_;
+    if (($dir eq '') || ($file eq '')) {
+        return FORBIDDEN;
+    }
+    if (open(my $config,"<","$dir/$file")) {
+        my $contents = join('',<$config>);
+        close($config);
+        $r->content_type($type);
+        $r->send_http_header;
+        return OK if $r->header_only;
+        $r->print($contents);
+        return OK;
+    } else {
+        return FORBIDDEN;
+    }
 }
 
 sub handler {
     my ($r) = @_;
 
+    my $reqhost = $r->get_remote_host(REMOTE_NOLOOKUP);
+    my @hostids= &Apache::lonnet::get_hosts_from_ip($reqhost);
+    if (!@hostids && $reqhost ne '127.0.0.1' ) {
+        $r->log_reason("Unable to find a host for ".
+                       $r->get_remote_host(REMOTE_NOLOOKUP));
+        return FORBIDDEN;
+    }
+
     my $command = (split('/',$r->uri))[3];
-    if ($command eq 'hosts') {
-	return &serve_file($r,'dns_hosts.tab','loncapa/hosts');
-    } elsif ($command eq 'domain') {
-	return &serve_file($r,'dns_domain.tab','loncapa/domain');
-    } elsif ($command eq 'checksums') {
-        my $version = (split('/',$r->uri))[4];
-        return &serve_file($r,"dns_checksums/$version.tab",'loncapa/versions');
+    my ($dir,$file) = &Apache::lonnet::parse_getdns_url($command,$r->uri);
+    my %types = (
+                    hosts      => 'loncapa/hosts',
+                    domain     => 'loncapa/domain',
+                    checksums  => 'loncapa/versions',
+                    loncapaCRL => 'application/x-pem-file',
+                );
+    if (exists($types{$command})) {
+        return &serve_file($r,$dir,$file,$types{$command});
     }
     return FORBIDDEN;
 }