void ResolveHost(DnsQuestion question)
{
IPAddress address;
if (IPAddress.TryParse(question.QueryName, out address))
{
Console.WriteLine("Ignored question for IP {0}.", address);
Cache.Add(question, new DnsCacheEntry {
Data = address.GetAddressBytes(),
TimeToLive = TimeSpan.FromMinutes(1)
});
}
else
{
byte[] addr = HostsFile[question.QueryName];
if (addr == null)
{
byte[] pkt = new DnsPacket {
RecursionDesired = true,
Questions = new [] {
question
}
}.ToByteArray();
Console.WriteLine("Question for {0}", question.QueryName);
foreach (UdpClient upstream in Upstreams)
{
upstream.Send(pkt, pkt.Length);
}
}
else
{
Console.WriteLine("Found {0} in hosts file.", question.QueryName);
Cache.Add(question, new DnsCacheEntry {
Data = addr,
TimeToLive = HostsFile.TimeToLive
});
}
}
}
void ReadCallback(IAsyncResult iar)
{
IPEndPoint endPoint = new IPEndPoint(Address, Port);
byte[] data = Listener.EndReceive(iar, ref endPoint);
Listener.BeginReceive(ReadCallback, null);
DnsPacket packet = new DnsPacket(data);
List <Task <DnsResourceRecord> > answers = new List <Task <DnsResourceRecord> >();
foreach (DnsQuestion question in packet.Questions)
{
if (question.QueryName.EndsWith(".proxyconfigurer.localhost"))
{
string query = question.QueryName.Substring(0, question.QueryName.Length - ".proxyconfigurer.localhost".Length);
string[] parts = query.Split('.');
string last = parts[parts.Length - 1];
ushort nonce;
if (last.StartsWith('n') && ushort.TryParse(last.Substring(1), out nonce))
{
if (parts[0] == "p")
{
answers.Add(Handler.GetConfigurationPacket(nonce).ContinueWith(t => new DnsResourceRecord {
Name = question.QueryName,
Type = question.Type,
Class = question.Class,
TimeToLive = t.Result.Item2,
Data = t.Result.Item1
}));
}
else
{
answers.Add(Handler.ResolveHost(nonce, int.Parse(parts[0].Substring(1))).ContinueWith(t => {
Task <DnsResourceRecord> task = Cache[new DnsQuestion {
QueryName = t.Result.Item1,
Type = question.Type,
Class = question.Class
}];
task.Wait();
task.Result.Name = question.QueryName;
task.Result.TimeToLive = Math.Min(task.Result.TimeToLive, t.Result.Item2);
return(task.Result);
}));
}
}
else
{
answers.Add(Handler.GetFirstConfigurationPacket(query).ContinueWith(t => new DnsResourceRecord {
Name = question.QueryName,
Type = question.Type,
Class = question.Class,
TimeToLive = t.Result.Item2,
Data = t.Result.Item1
}));
}
}
else
{
answers.Add(Cache[question]);
}
Console.WriteLine("Query for {0}", question.QueryName);
}
Task.WhenAll(answers).ContinueWith(t => {
byte[] pkt = new DnsPacket {
Identification = packet.Identification,
QueryResponse = true,
Questions = packet.Questions,
Answers = t.Result
}.ToByteArray();
Listener.Send(pkt, pkt.Length, endPoint);
});
}
