Add missing PTR records

[dns.git] / bin / mkgeo

diff --git a/bin/mkgeo b/bin/mkgeo
index fca95b24a9f309da0e8303958263c04f377419de..3a69d89af6639e476e78c61cc910a8dbd73656a8 100755 (executable)
--- a/bin/mkgeo
+++ b/bin/mkgeo
@@ -1,5 +1,7 @@
 #!/usr/bin/perl
 
 #!/usr/bin/perl
 

+use v5.12;
+

 use strict;
 use warnings;
 
 use strict;
 use warnings;
 


@@ -7,265 +9,496 @@ use IO::File;
 use Math::Trig qw(deg2rad pip2 great_circle_distance);
 use JSON::XS;
 use LWP::UserAgent;
 use Math::Trig qw(deg2rad pip2 great_circle_distance);
 use JSON::XS;
 use LWP::UserAgent;

-use XML::TreeBuilder;
-use YAML;
+use YAML::XS qw(LoadFile DumpFile);

 
 

-my $source = shift @ARGV;
+my $originfile = shift @ARGV;
+my $clusterfile = shift @ARGV;

 my $zone = shift @ARGV;
 my $zone = shift @ARGV;

-my $servers = YAML::LoadFile("src/${source}");
-
-# Initialise server details
-while (my($name,$server) = each %$servers)
+my $targetoriginfile = shift @ARGV;
+my $origins = LoadFile($originfile);
+my $clusters = LoadFile($clusterfile);
+my $gdnsname = shift @ARGV;
+my @servers;
+
+# Initialise cluster details
+while (my($name,$cluster) = each %$clusters)

 {
 {

-    $server->{name} = $name;
-    $server->{bandwidth} = $server->{bandwidth} * 1024 * 1024;
+    if ($cluster->{servers})
+    {
+        $cluster->{requests} = 0;
+
+        foreach my $server (@{$cluster->{servers}})
+        {
+            $server->{cluster} = $cluster;
+            $cluster->{requests} = $cluster->{requests} + $server->{requests};

 
 

-    if ($ENV{PINGDOM_USERNAME} && $ENV{PINGDOM_PASSWORD})
+            push @servers, $server;
+        }
+    }
+    elsif ($cluster->{requests} > 0)

     {
     {

-        $server->{status} = "down";
+        my $server = {
+            cluster => $cluster,
+            statuscake => $cluster->{statuscake},
+            requests => $cluster->{requests},
+            cname => $cluster->{cname},
+            ipv4 => $cluster->{ipv4},
+            ipv6 => $cluster->{ipv6}
+        };
+
+        $cluster->{servers} = [ $server ];
+
+        push @servers, $server;

     }
     else
     {
     }
     else
     {

-        $server->{status} = "up";
+        $cluster->{servers} = [];

     }
     }

+
+    $cluster->{name} = $name;
+    $cluster->{status} = "down";

 }
 
 }
 

-# If pingdom support is enabled then check which servers are up
-if ($ENV{PINGDOM_USERNAME} && $ENV{PINGDOM_PASSWORD})
+# Initialise server details
+foreach my $server (@servers)
+{
+    $server->{status} = "up";
+}
+
+# If statuscake support is enabled then check which servers are up
+if ($ENV{STATUSCAKE_APIKEY})

 {
     my $ua = LWP::UserAgent->new;
 {
     my $ua = LWP::UserAgent->new;

+    my $cache;

 
 

-    $ua->default_header("App-Key", "2cohi62u5haxvqmypk3ljqqrze1jufrh");
-    $ua->credentials("api.pingdom.com:443", "Pingdom API", $ENV{PINGDOM_USERNAME}, $ENV{PINGDOM_PASSWORD});
+    $ua->agent("mkgeo/1.0");
+    $ua->default_header("Authorization", "Bearer $ENV{STATUSCAKE_APIKEY}");

 
 

-    foreach my $server (values %$servers)
+    if (-f "statuscake.yml")
+    {
+        $cache = LoadFile("statuscake.yml");
+    }
+    else

     {
     {

-        if (my $checkid = $server->{pingdom})
+        $cache = {};
+    }
+
+    my $page = 1;
+    my $pages = 1;
+
+    while ($page <= $pages)
+    {
+        my $response = $ua->get("https://api.statuscake.com/v1/uptime?nouptime=true&limit=100&page=${page}");
+
+        if ($response->is_success)

         {
         {

-            my $response = $ua->get("https://api.pingdom.com/api/2.0/checks/${checkid}");
+            my $uptime = decode_json($response->content);

 
 

-            if ($response->is_success)
+            foreach my $test (@{$uptime->{data}})

             {
             {

-                my $check = decode_json($response->content);
+                my $testid = $test->{id};
+
+                if ($test->{status} eq "up" && !$test->{paused})
+                {
+                    $cache->{$testid} = "up";
+                }
+                else
+                {
+                    $cache->{$testid} = "down";
+                }
+            }

 
 

-                $server->{status} = $check->{check}->{status};
+            $page = $page + 1;
+            $pages = $uptime->{metadata}->{page_count};
+        }
+    }
+
+    foreach my $server (@servers)
+    {
+        if (my $testids = $server->{statuscake})
+        {
+            $server->{status} = "up";
+
+            for my $testid (@$testids)
+            {
+                my $testresult = $cache->{$testid} || "down";
+
+                $server->{status} = "down" if $testresult eq "down";

             }
         }
             }
         }

+        else
+        {
+            $server->{status} = "down";
+        }

     }
     }

-}

 
 

-my %countries = ();
-my @mappings = ();
+    DumpFile("statuscake-$$.yml", $cache);
+    rename("statuscake-$$.yml", "statuscake.yml");
+}

 
 

-# Create a parser for the country database
-my $countries = XML::TreeBuilder->new;
+# Mark a cluster as up if any servers are up
+foreach my $server (@servers)
+{
+    if ($server->{status} eq "up")
+    {
+        $server->{cluster}->{status} = "up";
+    }
+    else
+    {
+        $server->{cluster}->{requests} = $server->{cluster}->{requests} - $server->{requests};
+    }
+}

 
 

-# Parse the country database
-$countries->parsefile("lib/countries.xml");
+# Abort if no servers at all are up
+exit 0 unless grep { $_->{status} eq "up" } values(%$clusters);

 
 

-# Load the per-country bandwidth details
-my $bandwidth = YAML::LoadFile("bandwidth/${source}.yml");
+# Create target origins object
+my $targetorigins = {};

 
 

-# Fill in country table and work out which servers each can use
-foreach my $country ($countries->look_down("_tag" => "country"))
+# Initialise cluster details
+while (my($name,$cluster) = each %$clusters)

 {
 {

-    my $code = $country->look_down("_tag" => "countryCode")->as_text;
-    my $name = $country->look_down("_tag" => "countryName")->as_text;
-    my $population = $country->look_down("_tag" => "population")->as_text;
-    my $bandwidth = $bandwidth->{$code} || 0;
-    my $continent = $country->look_down("_tag" => "continent")->as_text;
-    my $west = $country->look_down("_tag" => "west")->as_text;
-    my $north = $country->look_down("_tag" => "north")->as_text;
-    my $east = $country->look_down("_tag" => "east")->as_text;
-    my $south = $country->look_down("_tag" => "south")->as_text;
-    my $lat = centre_lat( $south, $north );
-    my $lon = centre_lon( $west, $east );
-
-    $countries{$code} = {
-        code => $code, name => $name, continent => $continent,
-        bandwidth => $bandwidth, lat => $lat, lon => $lon
+    $cluster->{requests_limit} = $cluster->{requests};
+    $cluster->{requests_used} = 0;
+
+    next if $cluster->{global};
+
+    $targetorigins->{$cluster->{name}} = {
+        code => $cluster->{name},
+        name => $cluster->{name},
+        lat => $cluster->{lat},
+        lon => $cluster->{lon},
+        requests => 0

     };
     };

+}

 
 

-    foreach my $server (values %$servers)
+my @mappings = ();
+
+# Scan origins and work out which clusters each can use
+foreach my $origin (values %$origins)
+{
+    foreach my $cluster (values %$clusters)

     {
     {

-        my $match = match_country($server, $code, $continent);
+        my $match = match_origin($cluster, $origin);

 
 

-        if ($server->{status} eq "up" && $match ne "denied")
+        if ($cluster->{status} eq "up" && $match ne "denied")

         {
             my $priority = $match eq "preferred" ? 20 : 10;
         {
             my $priority = $match eq "preferred" ? 20 : 10;

-            my $distance = distance($lat, $lon, $server->{lat}, $server->{lon});
+            my $distance;
+
+            if ($cluster->{global})
+            {
+                $distance = 0;
+            }
+            else
+            {
+                $distance = distance($origin->{lat}, $origin->{lon}, $cluster->{lat}, $cluster->{lon});
+            }

 
             push @mappings, {
 
             push @mappings, {

-                country => $countries{$code}, server => $server,
+                origin => $origin, cluster => $cluster,

                 priority => $priority, distance => $distance
             };
         }
     }
 }
 
                 priority => $priority, distance => $distance
             };
         }
     }
 }
 

-# Discard the parsed country database
-$countries->delete;
+# Allocate each country to a cluster
+allocate_clusters(@mappings);

 
 

-# Loop over the mappings, trying to assign each country to the
-# nearest server, but subject to the bandwidth limits;
-foreach my $mapping (sort {  $b->{priority} <=> $a->{priority} || $a->{distance} <=> $b->{distance} } @mappings)
+# If we failed to allocate every origin then loop, increasing
+# the requests for each cluster by a little and retrying until
+# we manage to allocate everything
+while (grep { !exists($_->{cluster}) } values %$origins)

 {
 {

-    my $country = $mapping->{country};
-    my $server = $mapping->{server};
+    # Clear any existing mappings of countries to clusters
+    foreach my $origin (values %$origins)
+    {
+        delete $origin->{cluster};
+    }

 
 

-    if ($country->{bandwidth} <= $server->{bandwidth} && !exists($country->{server}))
+    # Reset requests usage for clusters and increase limits by 10%
+    foreach my $cluster (values %$clusters)

     {
     {

-        $country->{server} = $server;
-        $server->{bandwidth} = $server->{bandwidth} - $country->{bandwidth};
+        $cluster->{requests_used} = 0;
+        $cluster->{requests_limit} = $cluster->{requests_limit} * 1.1;

     }
     }

+
+    # Try the allocate again
+    allocate_clusters(@mappings);

 }
 
 }
 

-# Loop over the mappings again, assigning anything that is left
-# as best we can, and allowing bandwidth limits to be exeeded
-foreach my $mapping (sort {  $b->{priority} <=> $a->{priority} || $a->{distance} <=> $b->{distance} } @mappings)
+# Report on allocation results
+foreach my $name (sort keys %$clusters)

 {
 {

-    my $country = $mapping->{country};
-    my $server = $mapping->{server};
+    my $cluster = $clusters->{$name};
+    my $used = int($cluster->{requests_used} + 0.5);
+    my $limit = $cluster->{requests_limit};

 
 

-    $country->{server} = $server unless exists($country->{server});
+    if ($limit > 0)
+    {
+        my $proportion = int($used / $limit * 100 + 0.5);
+    
+        print "${name}: used ${used} of ${limit} (${proportion}%)\n";
+    }
+    else
+    {
+        print "${name}: used ${used} of ${limit}\n";
+    }

 }
 
 # Create JSON collection object
 my @json;
 
 # Open output files
 }
 
 # Create JSON collection object
 my @json;
 
 # Open output files

-my $zonefile = IO::File->new("> data/${zone}") || die "$!";
-my $jsonfile = IO::File->new("> json/${zone}.json") || die "$!";
+my $zonefile = IO::File->new("> include/${zone}.js") || die "$!";
+my $jsonfile = IO::File->new("> json/${zone}.openstreetmap.org.json") || die "$!";
+
+# Output headers
+$zonefile->print("var \U${zone}\E_RECORDS = [\n");

 
 # Output details for each country
 
 # Output details for each country

-foreach my $country (values %countries)
+foreach my $origin (sort { $a->{name} cmp $b->{name} } values %$origins)

 {
 {

-    my $server = $country->{server};
-    my $clon = $country->{lon};
-    my $clat = $country->{lat};
-    my $slon = $server->{lon};
-    my $slat = $server->{lat};
+    my $cluster = $origin->{cluster};

 
 

-    if ($clon > 0 && $slon < 0 && 360 + $slon - $clon < $clon - $slon)
+    if (!defined($gdnsname))

     {
     {

-        $slon = $slon + 360;
+        $zonefile->print("  CNAME(\"\L$origin->{code}\E.${zone}\", \"$cluster->{name}.${zone}.openstreetmap.org.\", TTL(\"10m\")),\n");

     }
     }

-    elsif ($slon > 0 && $clon < 0 && 360 + $clon - $slon < $slon - $clon)
+
+    if ($cluster->{lon} && $cluster->{lat})

     {
     {

-        $clon = $clon + 360;
+        my $clon = $origin->{lon};
+        my $clat = $origin->{lat};
+        my $slon = $cluster->{lon};
+        my $slat = $cluster->{lat};
+
+        if ($clon > 0 && $slon < 0 && 360 + $slon - $clon < $clon - $slon)
+        {
+            $slon = $slon + 360;
+        }
+        elsif ($slon > 0 && $clon < 0 && 360 + $clon - $slon < $slon - $clon)
+        {
+            $clon = $clon + 360;
+        }
+
+        push @json, {
+            type => "Feature",
+            geometry => {
+                type => "LineString",
+                coordinates => [ [ $clon, $clat ], [ $slon, $slat ] ]
+            },
+            properties => {
+                origin => $origin->{name},
+                server => $cluster->{name},
+                colour => $cluster->{colour}
+            }
+        };

     }
 
     }
 

-    $zonefile->print("# $country->{name}\n");
-    $zonefile->print("C\L$country->{code}\E.${zone}:$server->{name}.${zone}:600\n");
+    next if $cluster->{global};
+
+    $targetorigins->{$cluster->{name}}->{requests} += $origin->{requests};
+}

 
 

-    push @json, {
-        type => "Feature",
-        geometry => {
-            type => "LineString",
-            coordinates => [ [ $clon, $clat ], [ $slon, $slat ] ]
-        },
-        properties => {
-            country => $country->{name}
+# Skip default records if we don't need them
+if (!defined($gdnsname))
+{
+    # Output default records for IPs that can't be mapped to a country
+    foreach my $cluster (sort { $a->{name} cmp $b->{name} } values %$clusters)
+    {
+        my $name = $cluster->{name};
+
+        if (my $default = $cluster->{default})
+        {
+            output_server($zonefile, "${default}.${zone}", $cluster, 0);

         }
         }

-    };
+        elsif (exists($cluster->{default}))
+        {
+            output_server($zonefile, "${zone}", $cluster, 0);
+        }
+    }

 }
 
 }
 

-# Output default records for IPs that can't be mapped to a country
-foreach my $server (grep { $servers->{$_}->{default} } keys %$servers)
+# Output A records for each cluster
+foreach my $cluster (sort { $a->{name} cmp $b->{name} } values %$clusters)

 {
 {

-    $zonefile->print("Cxx.${zone}:${server}.${zone}:600\n");
+    my $name = $cluster->{name};
+
+    if (@{$cluster->{servers}} > 1)
+    {
+        output_server($zonefile, "${name}-%02d.${zone}", $cluster, 1);
+    }
+    else
+    {
+        output_server($zonefile, "${name}.${zone}", $cluster, 1);
+    }

 }
 
 # Output the GeoJSON text
 $jsonfile->print(encode_json(\@json));
 
 }
 
 # Output the GeoJSON text
 $jsonfile->print(encode_json(\@json));
 

+# Output footers
+$zonefile->print("];\n");
+

 # Close the output files
 # Close the output files

-$jsonfile->close();
+$zonefile->close();

 $zonefile->close();
 
 $zonefile->close();
 

-exit 0;
-
-#
-# Find the centre value between two latitudes
-#
-sub centre_lat
+# Output gdnsd configuration
+if (defined($gdnsname))

 {
 {

-    my $south = shift;
-    my $north = shift;
+    my $gdnsmapfile = IO::File->new("> gdns/${gdnsname}.map") || die "$!";
+    my $gdnsresourcefile = IO::File->new("> gdns/${gdnsname}.resource") || die "$!";
+    my $gdnsweightedfile = IO::File->new("> gdns/${gdnsname}.weighted") || die "$!";
+    my $continent = "";
+
+    $gdnsmapfile->print("${gdnsname} => {\n");
+    $gdnsmapfile->print("  geoip2_db => /etc/gdnsd/geoip/GeoLite2-Country.mmdb\n");
+    $gdnsmapfile->print("  datacenters => [" . join(",", sort(keys(%$clusters))) . "]\n");
+    $gdnsmapfile->print("  map => {\n");
+    $gdnsmapfile->print("    default => [" . join(",", sort(map { $_->{name} } grep { $_->{default} } values(%$clusters))) . "]\n");
+
+    foreach my $origin (sort { $a->{continent} cmp $b->{continent} || $a->{code} cmp $b->{code} } values %$origins)
+    {
+        my $code = $origin->{code};
+        my $cluster = $origin->{cluster}->{name};

 
 

-    return ( $south + $north ) / 2;
-}
+        next if $code eq "XK";

 
 

-#
-# Find the centre value between two longitudes
-#
-sub centre_lon
-{
-    my $west = shift;
-    my $east = shift;
-    my $lon;
+        if ($continent ne $origin->{continent})
+        {
+            $gdnsmapfile->print("    }\n") if $continent;

 
 

-    if ($west < $east)
-    {
-        $lon = ( $west + $east ) / 2;
+            $continent = $origin->{continent};
+
+            $gdnsmapfile->print("    ${continent} => {\n");
+        }
+
+        $gdnsmapfile->print("      ${code} => [${cluster}]\n");

     }
     }

-    else
+
+    $gdnsmapfile->print("    }\n") if $continent;
+
+    $gdnsmapfile->print("  }\n");
+    $gdnsmapfile->print("}\n");
+
+    $gdnsresourcefile->print("${gdnsname} => {\n");
+    $gdnsresourcefile->print("  map => ${gdnsname}\n");
+    $gdnsresourcefile->print("  dcmap => {\n");
+
+    foreach my $cluster (sort { $a->{name} cmp $b->{name} } values %$clusters)

     {
     {

-        $lon = ( $west + $east + 360 ) / 2;
+        my $name = $cluster->{name};
+
+        if (@{$cluster->{servers}} > 1 && grep { $_->{status} eq "up" } @{$cluster->{servers}})
+        {
+            $gdnsweightedfile->print("${name} => {\n");
+
+            while (my($index,$server) = each @{$cluster->{servers}})
+            {
+                if ($server->{status} eq "up")
+                {
+                    my $number = sprintf("%02d", $index + 1);
+                    my $requests = $server->{requests};
+
+                    if (my $cname = $server->{cname})
+                    {
+                        $gdnsweightedfile->print("  ${name}-${number} = [ ${cname}., ${requests} ]\n");
+                    }
+                    else
+                    {
+                        $gdnsweightedfile->print("  ${name}-${number} = [ ${name}-${number}.${zone}.openstreetmap.org., ${requests} ]\n");
+                    }
+                }
+            }
+
+            $gdnsweightedfile->print("}\n");
+
+            $gdnsresourcefile->print("    ${name} => %weighted!${name}\n");
+        }
+        elsif (my $cname = $cluster->{cname})
+        {
+            $gdnsresourcefile->print("    ${name} => ${cname}.\n");
+        }
+        else
+        {
+            $gdnsresourcefile->print("    ${name} => ${name}.${zone}.openstreetmap.org.\n");
+        }

     }
 
     }
 

-    $lon = $lon - 360 if $lon > 180;
+    $gdnsresourcefile->print("  }\n");
+    $gdnsresourcefile->print("}\n");

 
 

-    return $lon
+    $gdnsweightedfile->close();
+    $gdnsresourcefile->close();
+    $gdnsmapfile->close();

 }
 
 }
 

+# Output the target details in origin format if required
+DumpFile($targetoriginfile, $targetorigins) if $targetoriginfile;
+
+exit 0;
+

 #
 #

-# Match a country against a server
+# Match an origin against a cluster

 #
 #

-sub match_country
+sub match_origin

 {
 {

-    my $server = shift;
-    my $country = shift;
-    my $continent = shift;
+    my $cluster = shift;
+    my $origin = shift;

     my $match;
 
     my $match;
 

-    if ($server->{preferred} &&
-        $server->{preferred}->{countries} &&
-        grep { $_ eq $country } @{$server->{preferred}->{countries}})
+    if ($cluster->{preferred} &&
+        $cluster->{preferred}->{origins} &&
+        grep { $_ eq $origin->{name} } @{$cluster->{preferred}->{origins}})

     {
         $match = "preferred";
     }
     {
         $match = "preferred";
     }

-    elsif ($server->{preferred} &&
-           $server->{preferred}->{continents} &&
-           grep { $_ eq $continent } @{$server->{preferred}->{continents}})
+    elsif ($cluster->{allowed} &&
+           $cluster->{allowed}->{origins} &&
+           grep { $_ eq $origin->{name} } @{$cluster->{allowed}->{origins}})

     {
     {

-        $match = "preferred";
+        $match = "allowed";

     }
     }

-    elsif ($server->{allowed} &&
-           $server->{allowed}->{countries} &&
-           grep { $_ eq $country } @{$server->{allowed}->{countries}})
+    elsif ($cluster->{preferred} &&
+           $cluster->{preferred}->{countries} &&
+           grep { $_ eq $origin->{country} } @{$cluster->{preferred}->{countries}})

     {
     {

-        $match = "allowed";
+        $match = "preferred";

     }
     }

-    elsif ($server->{allowed} &&
-           $server->{allowed}->{continents} &&
-           grep { $_ eq $continent } @{$server->{allowed}->{continents}})
+    elsif ($cluster->{allowed} &&
+           $cluster->{allowed}->{countries} &&
+           grep { $_ eq $origin->{country} } @{$cluster->{allowed}->{countries}})

     {
         $match = "allowed";
     }
     {
         $match = "allowed";
     }

-    elsif ($server->{denied} &&
-        $server->{denied}->{countries} &&
-        grep { $_ eq $country } @{$server->{preferred}->{countries}})
+    elsif ($cluster->{denied} &&
+           $cluster->{denied}->{countries} &&
+           grep { $_ eq $origin->{country} } @{$cluster->{denied}->{countries}})

     {
         $match = "denied";
     }
     {
         $match = "denied";
     }

-    elsif ($server->{denied} &&
-           $server->{denied}->{continents} &&
-           grep { $_ eq $continent } @{$server->{preferred}->{continents}})
+    elsif ($cluster->{preferred} &&
+           $cluster->{preferred}->{continents} &&
+           grep { $_ eq $origin->{continent} } @{$cluster->{preferred}->{continents}})
+    {
+        $match = "preferred";
+    }
+    elsif ($cluster->{allowed} &&
+           $cluster->{allowed}->{continents} &&
+           grep { $_ eq $origin->{continent} } @{$cluster->{allowed}->{continents}})
+    {
+        $match = "allowed";
+    }
+    elsif ($cluster->{denied} &&
+           $cluster->{denied}->{continents} &&
+           grep { $_ eq $origin->{continent} } @{$cluster->{denied}->{continents}})

     {
         $match = "denied";
     }
     {
         $match = "denied";
     }

-    elsif ($server->{allowed})
+    elsif ($cluster->{allowed})

     {
         $match = "denied";
     }
     {
         $match = "denied";
     }


@@ -289,3 +522,92 @@ sub distance
 
     return great_circle_distance($lon1, pip2 - $lat1, $lon2, pip2 - $lat2);
 }
 
     return great_circle_distance($lon1, pip2 - $lat1, $lon2, pip2 - $lat2);
 }

+
+#
+# Allocate each origin to a cluster
+#
+sub allocate_clusters
+{
+    my @mappings = sort { compare_mappings($a, $b) } @_;
+
+    # Loop over the mappings, trying to assign each origin to the
+    # nearest cluster, but subject to the request limits
+    while (my $mapping = shift @mappings)
+    {
+        my @group;
+
+        push @group, $mapping;
+
+        while (@mappings && compare_mappings($mapping, $mappings[0]) == 0)
+        {
+            push @group, shift @mappings;
+        }
+
+        for my $mapping (sort compare_requests @group)
+        {
+            my $origin = $mapping->{origin};
+            my $cluster = $mapping->{cluster};
+
+            if (!exists($origin->{cluster}) &&
+                $cluster->{requests_used} + $origin->{requests} <= $cluster->{requests_limit})
+            {
+                $origin->{cluster} = $cluster;
+                $cluster->{requests_used} = $cluster->{requests_used} + $origin->{requests};
+            }
+        }
+    }
+
+    return;
+}
+
+#
+# Compare two mappings to decide which to use
+#
+sub compare_mappings
+{
+    my $a = shift;
+    my $b = shift;
+
+    return $b->{priority} <=> $a->{priority} ||
+           $a->{distance} <=> $b->{distance};
+}
+
+#
+# Compare two mappings to decide which to try first
+#
+sub compare_requests
+{
+    my $a_used = ( $a->{cluster}->{requests_used} * 100.0 ) / ( $a->{cluster}->{requests_limit} * 1.0 );
+    my $b_used = ( $b->{cluster}->{requests_used} * 100.0 ) / ( $b->{cluster}->{requests_limit} * 1.0 );
+
+    return $a_used <=> $b_used;
+}
+
+#
+# Output DNS records for a server
+#
+sub output_server
+{
+    my $zonefile = shift;
+    my $name = shift;
+    my $cluster = shift;
+    my $all = shift;
+
+    while (my($index,$server) = each @{$cluster->{servers}})
+    {
+        if ($all || $server->{status} eq "up")
+        {
+            if ($server->{ipv4})
+            {
+                $zonefile->printf("  A(\"${name}\", \"$server->{ipv4}\", TTL(\"10m\")),\n", $index + 1);
+            }
+
+            if ($server->{ipv6})
+            {
+                $zonefile->printf("  AAAA(\"${name}\", \"$server->{ipv6}\", TTL(\"10m\")),\n", $index + 1);
+            }
+        }
+    }
+
+    return;
+}