public void TestMinimumConfigFile()
{
// The smallest file that you can get away with is an empty zone, which has just an SOA
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""7200""
primary-ns=""ns.example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
</zone>
" );
var zone = DNSZone.Unserialize(config);
Assert.That(zone.Relays, Is.Empty);
Assert.That(zone.StartOfAuthority, Is.EqualTo(
new DNSRecord(
new Domain("example.com"),
AddressClass.INTERNET,
7200,
new SOAResource(
new Domain("ns.example.com"),
new Domain("admin.example.com"),
0,
3600,
60,
3600,
60))));
}
public static void Main(string[] args)
{
if (args.Length != 3)
{
Console.WriteLine("Usage: dns-server <config-file> <ip-address> <port>");
Environment.Exit(1);
}
var config = new XmlDocument();
config.Load(args[0]);
var zone = DNSZone.Unserialize(config);
var clock = new StopwatchClock();
var cache = new ResolverCache(clock, 2048);
var resolver = new StubResolver(cache, ResolverUtils.SendQuery);
var query_exec = new QueryExecutor(zone, resolver, cache);
var bind_addr = new IPEndPoint(IPAddress.Parse(args[1]),
int.Parse(args[2]));
var server = new UDPServer(bind_addr, query_exec);
server.Start();
}
public void TestNotAuthorityWhenPTRIsUnknown()
{
// We can't be authorities for PTR records we don't recognize
var zone = new DNSZone(start_of_authority, relays);
Assert.That(zone.IsAuthorityFor(new Domain("1.0.168.192.in-addr.arpa")), Is.False);
}
public void TestEmptyConfigFileFails()
{
// The empty configuration file is not valid, since it lacks a SOA
var config = ParseXML("<zone></zone>");
Assert.Throws <InvalidDataException>(() => DNSZone.Unserialize(config));
}
public void TestNotAuthorityWithoutDelegation()
{
// Ensure that we are not considered authoritative for things clearly
// outside of our zone
var zone = new DNSZone(start_of_authority, relays);
Assert.That(zone.IsAuthorityFor(new Domain("bogus.com")), Is.False);
}
public void TestNoSubzoneAuthoritative()
{
// Ensures that we don't return a subzone for things we're directly an
// authority for
var zone = new DNSZone(start_of_authority, relays);
Assert.That(zone.FindSubZone(new Domain("www.example.com")), Is.Null);
}
public void TestAuthorityWithoutDelegation()
{
// Ensure that we are considered authoritative for things that
// are in our zone (without involvement by subzones)
var zone = new DNSZone(start_of_authority, relays);
Assert.That(zone.IsAuthorityFor(new Domain("www.example.com")), Is.True);
}
public void TestNoSubzoneNotAuthoritatie()
{
// Ensures that we don't return a subzone for things that are outside of
// our authority
var zone = new DNSZone(start_of_authority, relays);
Assert.That(zone.FindSubZone(new Domain("bogus.com")), Is.Null);
}
public void TestSOABadPrimaryNS()
{
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""3600""
primary-ns=""....example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
</zone>
" );
Assert.Throws <InvalidDataException>(() => DNSZone.Unserialize(config));
}
public void TestSOAMissingMinTTL()
{
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""3600""
primary-ns=""ns.example.com"" hostmaster=""hostmaster.example.com""
refresh=""3600"" retry=""3600"" expire=""3600"" />
</zone>
" );
Assert.Throws <InvalidDataException>(() => DNSZone.Unserialize(config));
}
public void TestHighTTLFails()
{
// TTLs are 32-bit numbers, so any TTL over 136 years doesn't work
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""9999999999""
primary-ns=""ns.example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
</zone>
" );
Assert.Throws <InvalidDataException>(() => DNSZone.Unserialize(config));
}
public void TestAuthorityWhenPTRIsKnownV6()
{
// We should be an authority for a PTR record that we know about
var zone = new DNSZone(start_of_authority, relays);
var ptr = new DNSRecord(
new Domain("b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.ip6.arpa"),
AddressClass.INTERNET,
42,
new PTRResource(new Domain("www.example.com")));
zone.Add(ptr);
Assert.That(zone.IsAuthorityFor(new Domain("b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.ip6.arpa")), Is.True);
}
public void TestRelayTooHighPort()
{
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""7200""
primary-ns=""ns.example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
<relay address=""192.168.0.1"" port=""1000000"" />
</zone>
" );
Assert.Throws <InvalidDataException>(() => DNSZone.Unserialize(config));
}
public void TestPTRMissingPointer()
{
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""3600""
primary-ns=""ns.example.com"" hostmaster=""hostmaster.example.com""
refresh=""3600"" retry=""3600"" expire=""3600"" />
<PTR name=""1.0.168.192.in-addr.arpa"" class=""IN"" ttl=""3600"" />
</zone>
" );
Assert.Throws <InvalidDataException>(() => DNSZone.Unserialize(config));
}
public void TestMXGarbageMailserver()
{
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""3600""
primary-ns=""ns.example.com"" hostmaster=""hostmaster.example.com""
refresh=""3600"" retry=""3600"" expire=""3600"" />
<MX name=""example.com"" class=""IN"" ttl=""3600"" priority=""1"" mailserver="".....example.com"" />
</zone>
" );
Assert.Throws <InvalidDataException>(() => DNSZone.Unserialize(config));
}
public void TestAuthorityWithDelegation()
{
// Ensures that we're not an authority for things that are subzones
var zone = new DNSZone(start_of_authority, relays);
var subzone = new DNSRecord(
new Domain("foo.example.com"),
AddressClass.INTERNET,
42,
new NSResource(new Domain("ns.foo.example.com")));
zone.Add(subzone);
Assert.That(zone.IsAuthorityFor(new Domain("www.foo.example.com")), Is.False);
}
public void TestAIPv6Address()
{
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""3600""
primary-ns=""ns.example.com"" hostmaster=""hostmaster.example.com""
refresh=""3600"" retry=""3600"" expire=""3600"" />
<A name=""example.com"" class=""IN"" ttl=""3600"" address=""2001:beef:cafe::1337"" />
</zone>
" );
Assert.Throws <InvalidDataException>(() => DNSZone.Unserialize(config));
}
public void TestAuthorityWhenEqualToDelegation()
{
// Ensure that we are an authority for the subzone's address itself (which can
// occur if, say, there's a CNAME pointing to it)
var zone = new DNSZone(start_of_authority, relays);
var subzone = new DNSRecord(
new Domain("foo.example.com"),
AddressClass.INTERNET,
42,
new NSResource(new Domain("ns.foo.example.com")));
zone.Add(subzone);
Assert.That(zone.IsAuthorityFor(new Domain("foo.example.com")), Is.True);
}
public void TestSubzoneWithDelegation()
{
// Ensure that we can find the subzone for a domain in that subzone
var zone = new DNSZone(start_of_authority, relays);
var subzone = new DNSRecord(
new Domain("foo.example.com"),
AddressClass.INTERNET,
42,
new NSResource(new Domain("ns.foo.example.com")));
zone.Add(subzone);
Assert.That(zone.FindSubZone(new Domain("www.foo.example.com")),
Is.EqualTo(new Domain("foo.example.com")));
}
public void TestRelayGarbagePort()
{
// The smallest file that you can get away with is an empty zone, which has just an SOA
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""7200""
primary-ns=""ns.example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
<relay address=""192.168.0.1"" port=""blargh"" />
</zone>
" );
Assert.Throws <InvalidDataException>(() => DNSZone.Unserialize(config));
}
public void TestMultipleSOAFails()
{
// Multiple SOA records are not allowed, since we currently don't support multiple zones
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""7200""
primary-ns=""ns.example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
<SOA name=""fabrikam.com"" class=""IN"" ttl=""7200""
primary-ns=""ns.example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
</zone>
" );
Assert.Throws <InvalidDataException>(() => DNSZone.Unserialize(config));
}
public void TestQuery()
{
var zone = new DNSZone(start_of_authority, relays);
var www_a_record = new DNSRecord(
new Domain("www.example.com"),
AddressClass.INTERNET,
42,
new AResource(IPv4Address.Parse("192.168.0.1")));
var www_a_record_2 = new DNSRecord(
new Domain("www.example.com"),
AddressClass.INTERNET,
42,
new AResource(IPv4Address.Parse("192.168.0.2")));
// Something that matches the class and record type, but not the domain
var www2_a_record = new DNSRecord(
new Domain("www2.example.com"),
AddressClass.INTERNET,
42,
new AResource(IPv4Address.Parse("192.168.0.3")));
// Something that matches the domain and class, but not the record type
var www_cname_record = new DNSRecord(
new Domain("www.example.com"),
AddressClass.INTERNET,
42,
new CNAMEResource(new Domain("www2.example.com")));
zone.Add(www_a_record);
zone.Add(www_a_record_2);
zone.Add(www2_a_record);
zone.Add(www_cname_record);
var query_result = zone.Query(
new Domain("www.example.com"),
ResourceRecordType.HOST_ADDRESS,
AddressClass.INTERNET);
var expected = new List <DNSRecord>();
expected.Add(www_a_record);
expected.Add(www_a_record_2);
Assert.That(query_result, Is.EquivalentTo(expected));
}
public void TestConfigRelay()
{
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""7200""
primary-ns=""ns.example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
<relay address=""192.168.0.1"" port=""53"" />
</zone>
" );
var zone = DNSZone.Unserialize(config);
var relays = new EndPoint[] {
new IPEndPoint(IPAddress.Parse("192.168.0.1"), 53)
};
Assert.That(zone.Relays, Is.EquivalentTo(relays));
}
public void TestConfigMXRecord()
{
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""7200""
primary-ns=""ns.example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
<MX name=""example.com"" class=""IN"" ttl=""3600"" priority=""42"" mailserver=""smtp.example.com"" />
</zone>
" );
var zone = DNSZone.Unserialize(config);
var records = new List <DNSRecord>();
records.Add(new DNSRecord(
new Domain("example.com"),
AddressClass.INTERNET,
3600,
new MXResource(42, new Domain("smtp.example.com"))));
Assert.That(zone.Records, Is.EquivalentTo(records));
}
public void TestConfigAAAARecord()
{
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""7200""
primary-ns=""ns.example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
<AAAA name=""www.example.com"" class=""IN"" ttl=""3600"" address=""2001:0DB8:AC10:FE01:0000:0000:0000:0000"" />
</zone>
" );
var zone = DNSZone.Unserialize(config);
var records = new List <DNSRecord>();
records.Add(new DNSRecord(
new Domain("www.example.com"),
AddressClass.INTERNET,
3600,
new AAAAResource(IPv6Address.Parse("2001:0DB8:AC10:FE01:0000:0000:0000:0000"))));
Assert.That(zone.Records, Is.EquivalentTo(records));
}
public void TestSOAMinTTLIsEnforced()
{
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""7200""
primary-ns=""ns.example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
<A name=""www.example.com"" class=""IN"" ttl=""5"" address=""192.168.0.1"" />
</zone>
" );
var zone = DNSZone.Unserialize(config);
var records = new List <DNSRecord>();
records.Add(new DNSRecord(
new Domain("www.example.com"),
AddressClass.INTERNET,
60,
new AResource(IPv4Address.Parse("192.168.0.1"))));
Assert.That(zone.Records, Is.EquivalentTo(records));
}
public void TestConfigPTRRecordV6()
{
var config = ParseXML(@"
<zone>
<SOA name=""example.com"" class=""IN"" ttl=""7200""
primary-ns=""ns.example.com"" hostmaster=""admin.example.com""
serial=""0"" refresh=""3600"" retry=""60"" expire=""3600"" min-ttl=""60"" />
<PTR name=""b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.ip6.arpa"" class=""IN"" ttl=""3600"" pointer=""www.example.com"" />
</zone>
" );
var zone = DNSZone.Unserialize(config);
var records = new List <DNSRecord>();
records.Add(new DNSRecord(
new Domain("b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.ip6.arpa"),
AddressClass.INTERNET,
3600,
new PTRResource(new Domain("www.example.com"))));
Assert.That(zone.Records, Is.EquivalentTo(records));
}
/**
* Produces a new zone from an input XML file.
*/
public static DNSZone Unserialize(XmlDocument config)
{
DNSRecord start_of_authority = null;
var records = new List <DNSRecord>();
var relays = new List <EndPoint>();
if (config.DocumentElement.Name != "zone")
{
throw new InvalidDataException("Root element must be called zone");
}
foreach (var entry in config.DocumentElement.ChildNodes.OfType <XmlNode>())
{
if (entry.NodeType != XmlNodeType.Element)
{
logger.Trace("Ignoring node of type {0}", entry.NodeType);
continue;
}
bool is_record =
entry.Name == "A" ||
entry.Name == "NS" ||
entry.Name == "CNAME" ||
entry.Name == "MX" ||
entry.Name == "SOA" ||
entry.Name == "PTR" ||
entry.Name == "AAAA";
if (is_record)
{
if (entry.Attributes["name"] == null ||
entry.Attributes["class"] == null ||
entry.Attributes["ttl"] == null)
{
throw new InvalidDataException("Resource records must have 'name', 'class' and 'ttl' attributes");
}
var record_name = new Domain(entry.Attributes["name"].Value);
AddressClass record_class;
switch (entry.Attributes["class"].Value)
{
case "IN":
record_class = AddressClass.INTERNET;
break;
default:
throw new InvalidDataException("Only address class 'IN' is supported");
}
UInt32 record_ttl = 0;
try
{
record_ttl = UInt32.Parse(entry.Attributes["ttl"].Value);
}
catch (Exception err)
{
if (err is OverflowException || err is FormatException)
{
throw new InvalidDataException(entry.Attributes["ttl"].Value + " is not a valid TTL");
}
else
{
throw;
}
}
IDNSResource resource = null;
switch (entry.Name)
{
case "A":
if (entry.Attributes["address"] == null)
{
throw new InvalidDataException("A record must have address");
}
IPv4Address address;
try
{
address = IPv4Address.Parse(entry.Attributes["address"].Value);
}
catch (FormatException)
{
throw new InvalidDataException(entry.Attributes["address"].Value + " is not a valid IPv4 address");
}
resource = new AResource(address);
logger.Trace("A record: address={0}", ((AResource)resource).Address);
break;
case "NS":
if (entry.Attributes["nameserver"] == null)
{
throw new InvalidDataException("NS record must have a nameserver");
}
resource = new NSResource(new Domain(entry.Attributes["nameserver"].Value));
logger.Trace("NS record: nameserver={0}", ((NSResource)resource).Nameserver);
break;
case "CNAME":
if (entry.Attributes["alias"] == null)
{
throw new InvalidDataException("CNAME record must have an alias");
}
resource = new CNAMEResource(new Domain(entry.Attributes["alias"].Value));
logger.Trace("CNAME record: alias={0}", ((CNAMEResource)resource).Alias);
break;
case "MX":
if (entry.Attributes["priority"] == null ||
entry.Attributes["mailserver"] == null)
{
throw new InvalidDataException("MX record must have priority and mailserver");
}
var mailserver = new Domain(entry.Attributes["mailserver"].Value);
UInt16 preference = 0;
try
{
preference = UInt16.Parse(entry.Attributes["priority"].Value);
}
catch (Exception err)
{
if (err is OverflowException || err is FormatException)
{
throw new InvalidDataException(entry.Attributes["priority"].Value + " is not a valid priority value");
}
else
{
throw;
}
}
resource = new MXResource(preference, mailserver);
logger.Trace("MX record: priority={0} mailserver={1}",
((MXResource)resource).Preference,
((MXResource)resource).Mailserver);
break;
case "PTR":
if (entry.Attributes["pointer"] == null)
{
throw new InvalidDataException("PTR record must have pointer");
}
if (!reverse_zone_v4.IsSubdomain(record_name) && !reverse_zone_v6.IsSubdomain(record_name))
{
throw new InvalidDataException("PTR record be in the in-addr.arpa or ip6.arpa zone");
}
resource = new PTRResource(new Domain(entry.Attributes["pointer"].Value));
logger.Trace("PTR record: pointer={0}", ((PTRResource)resource).Pointer);
break;
case "AAAA":
if (entry.Attributes["address"] == null)
{
throw new InvalidDataException("AAAA record must have address");
}
IPv6Address v6address;
try
{
v6address = IPv6Address.Parse(entry.Attributes["address"].Value);
}
catch (FormatException)
{
throw new InvalidDataException(entry.Attributes["address"].Value + " is not a valid IPv4 address");
}
resource = new AAAAResource(v6address);
logger.Trace("AAAA record: address={0}", ((AAAAResource)resource).Address);
break;
case "SOA":
if (entry.Attributes["primary-ns"] == null ||
entry.Attributes["hostmaster"] == null ||
entry.Attributes["serial"] == null ||
entry.Attributes["refresh"] == null ||
entry.Attributes["retry"] == null ||
entry.Attributes["expire"] == null ||
entry.Attributes["min-ttl"] == null)
{
throw new InvalidDataException("SOA record missing one of: primary-ns, hostmaster, serial, refresh, retry, expire and min-ttl");
}
var primary_ns = new Domain(entry.Attributes["primary-ns"].Value);
var hostmaster = new Domain(entry.Attributes["hostmaster"].Value);
UInt32 serial = 0;
try
{
serial = UInt32.Parse(entry.Attributes["serial"].Value);
}
catch (Exception err)
{
if (err is OverflowException || err is FormatException)
{
throw new InvalidDataException(entry.Attributes["serial"].Value + " is not a valid serial number");
}
else
{
throw;
}
}
UInt32 refresh = 0;
try
{
refresh = UInt32.Parse(entry.Attributes["refresh"].Value);
}
catch (Exception err)
{
if (err is OverflowException || err is FormatException)
{
throw new InvalidDataException(entry.Attributes["refresh"].Value + " is not a valid refresh value");
}
else
{
throw;
}
}
UInt32 retry = 0;
try
{
retry = UInt32.Parse(entry.Attributes["retry"].Value);
}
catch (Exception err)
{
if (err is OverflowException || err is FormatException)
{
throw new InvalidDataException(entry.Attributes["retry"].Value + " is not a valid retry value");
}
else
{
throw;
}
}
UInt32 expire = 0;
try
{
expire = UInt32.Parse(entry.Attributes["expire"].Value);
}
catch (Exception err)
{
if (err is OverflowException || err is FormatException)
{
throw new InvalidDataException(entry.Attributes["expire"].Value + " is not a valid expire value");
}
else
{
throw;
}
}
UInt32 minttl = 0;
try
{
minttl = UInt32.Parse(entry.Attributes["min-ttl"].Value);
}
catch (Exception err)
{
if (err is OverflowException || err is FormatException)
{
throw new InvalidDataException(entry.Attributes["min-ttl"].Value + " is not a valid expire value");
}
else
{
throw;
}
}
resource = new SOAResource(primary_ns, hostmaster, serial, refresh, retry, expire, minttl);
logger.Trace("SOA record: primary-ns={0} hostmaster={1} serial={2} refresh={3} retry={4} expire={5} min-ttl={6}",
((SOAResource)resource).PrimaryNameServer,
((SOAResource)resource).Hostmaster,
((SOAResource)resource).Serial,
((SOAResource)resource).RefreshSeconds,
((SOAResource)resource).RetrySeconds,
((SOAResource)resource).ExpireSeconds,
((SOAResource)resource).MinimumTTL);
break;
}
var record = new DNSRecord(record_name, record_class, record_ttl, resource);
if (record.Resource.Type == ResourceRecordType.START_OF_AUTHORITY)
{
if (start_of_authority == null)
{
logger.Trace("Found SOA: {0}", record);
start_of_authority = record;
}
else
{
throw new InvalidDataException("Cannot have more than one SOA record in zone");
}
}
else
{
logger.Trace("Found other record: {0}", record);
records.Add(record);
}
}
else if (entry.Name == "relay")
{
if (entry.Attributes["address"] == null ||
entry.Attributes["port"] == null)
{
throw new InvalidDataException("relay record must have address and port");
}
IPAddress address;
int port;
try
{
address = IPAddress.Parse(entry.Attributes["address"].Value);
}
catch (FormatException)
{
throw new InvalidDataException(entry.Attributes["address"].Value + " is not a valid IPv4 address");
}
try
{
port = int.Parse(entry.Attributes["port"].Value);
}
catch (FormatException)
{
throw new InvalidDataException(entry.Attributes["port"].Value + " is not a valid port");
}
try
{
relays.Add(new IPEndPoint(address, port));
}
catch (ArgumentOutOfRangeException)
{
throw new InvalidDataException(entry.Attributes["port"].Value + " is not a valid port");
}
logger.Trace("Found relay: {0}:{1}", address, port);
}
else
{
throw new InvalidDataException(entry.Name + " is not a valid zone entry");
}
}
if (start_of_authority == null)
{
throw new InvalidDataException("Zone does not have SOA record");
}
var zone = new DNSZone(start_of_authority, relays.ToArray());
foreach (var record in records)
{
if (record.TimeToLive < ((SOAResource)start_of_authority.Resource).MinimumTTL)
{
logger.Trace("Correcting TTL: Record {0} has smaller TTL than SOA MinTTL {1}",
record, start_of_authority);
record.TimeToLive = ((SOAResource)start_of_authority.Resource).MinimumTTL;
}
zone.Add(record);
}
return(zone);
}
public QueryExecutor(DNSZone zone, IResolver resolver, IDNSCache cache)
{
this.zone = zone;
this.resolver = resolver;
this.cache = cache;
}
