Changeset 752

Timestamp:

06/01/17 16:52:55 (8 years ago)

Author:

Kris Deugau

Message:

/trunk

Minor administrivia cleanups

Mostly finalize new ALIAS pseudotype. See #55.

• Add validator
• Tweak handling of ALIAS IP cache with new DB column
• Fix an output typo that would have created broken record lines

File:

• trunk/DNSDB.pm (modified) (4 diffs)

trunk/DNSDB.pm

@@ -3 +3 @@
 ##
 # $Id$
-# Copyright 2008-2016 Kris Deugau <kdeugau@deepnet.cx>
+# Copyright 2008-2017 Kris Deugau <kdeugau@deepnet.cx>
 # 
 #    This program is free software: you can redistribute it and/or modify
@@ -1369 +1369 @@
   }
   return ('OK','OK');
-}
+} # done delegation record
+
+# ALIAS record
+# A specialized variant of the CNAME, which retrieves the A record list on each
+# export and publishes the A records instead.  Primarily for "root CNAME" or "apex
+# alias" records.  See https://secure.deepnet.cx/trac/dnsadmin/ticket/55.
+# Not allowed in reverse zones because this is already a hack, and reverse zones
+# don't get pointed to CNAMEed CDNs the way domains do.
+sub _validate_65300 {
+  my $self = shift;
+  my $dbh = $self->{dbh};
+
+  my %args = @_;
+
+  return ('FAIL',"ALIAS records are not permitted in reverse zones") if $args{revrec} eq 'y';
+
+  # Make sure target is a well-formed hostname
+  return ('FAIL', $errstr) if ! _check_hostname_form(${$args{val}}, ${$args{rectype}}, $args{defrec}, $args{revrec});
+
+  # Coerce all hostnames to end in ".DOMAIN" for group/default records,
+  # or the intended parent domain for live records.
+  my $pname = ($args{defrec} eq 'y' ? 'DOMAIN' : $self->domainName($args{id}));
+  ${$args{host}} =~ s/\.*$/\.$pname/ if (${$args{host}} ne '@' && ${$args{host}} !~ /$pname$/i);  
+
+  # don't do the cache thing on default records
+  return ('OK','OK') if $defrec ne 'n';
+
+  # now we check/update the cached target address info
+  my ($iplist) = $self->{dbh}->selectrow_array("SELECT auxdata FROM records WHERE record_id = ?", undef, $args{recid});
+  my $warnmsg;
+
+  my $res = Net::DNS::Resolver->new;
+  # Set short timeouts to minimize disruption.  If the target's DNS is slow the site will likely be broken anyway.
+  $res->tcp_timeout(2);
+  $res->udp_timeout(2);
+  my $reply = $res->query(${$args{val}});
+  my @newlist;
+  if ($reply) { 
+    foreach my $rr ($reply->answer) {
+      next unless $rr->type eq "A";
+      push @newlist, $rr->address;
+    }
+  } else {
+    $warnmsg = "Failure retrieving IP list from DNS for cache validation/update on ALIAS '${$args{host}} -> ${$args{val}}': ".$res->errors$
+  }
+
+  # we don't need this to be perfectly correct IP address order, just consistent.
+  my $liveips = join(':', sort(@newlist));
+
+  # check to see if there was an OOOOPS checking for updated A records on the target.  also make sure we have something cached.
+  if (!$liveips) {
+    if (!$iplist) {
+      # not fatal since we do the lookup on export as well
+      return ('WARN',
+        join("\n", $warnmsg, "No cached data and no live DNS data for ALIAS target ${$args{val}};  record may be SKIPPED on export!") );
+#    } else {
+#      return ('WARN', "No live DNS data for ALIAS target ${$args{val}};  falling back to cache");
+    }
+  }
+
+  # munge the insert/update fieldlist and data array
+  if ($iplist ne $liveips) {
+    ${$args{fields}} .= "auxdata,";
+    push @{$args{vallist}}, $liveips;
+  }
+
+  return ('WARN', $warnmsg) if $warnmsg;
+  
+  return ('OK','OK');
+} # done ALIAS record
+
 
 # Subs not specific to a particular record type
@@ -6664 +6734 @@
     return if $revrec eq 'y';
 
-    my ($target,$iplist) = split /:/, $val, 2;
+    my ($iplist) = $self->{dbh}->selectrow_array("SELECT auxdata FROM records WHERE record_id = ?", undef, $recid);
     my $res = Net::DNS::Resolver->new;
-    my $reply = $res->query($target);
-
-    if ($reply) { 
+    my $reply = $res->query($val);
+
+    if ($reply) {
       my $liveips;
       my @newlist;
@@ -6679 +6749 @@
       if ($iplist ne $liveips) {
         # update the cache of IPs from the target
-        $self->{dbh}->do("UPDATE records SET val=? WHERE record_id=?", undef, "$target:$liveips", $recid);
+        $self->{dbh}->do("UPDATE records SET auxdata = ? WHERE record_id = ?", undef, $liveips, $recid);
         $iplist = $liveips;
       }
     } else {
-      warn "Failure retrieving IP list for cache validation/update on ALIAS '$host -> $target': ", $res->errorstring, "\n";
+      warn "Failure retrieving IP list for cache validation/update on ALIAS '$host -> $val': ", $res->errorstring, "\n";
     }
 
     # output a plain old A record for each IP the target name really points to.
     foreach my $subip (split ':', $iplist) {
-      print "+$host:$subip:$ttl,$stamp,$loc\n" or die $!;
+      print "+$host:$subip:$ttl:$stamp:$loc\n" or die $!;
     }