/// <summary>
/// Processes incomming initial packet and creates or halts a connection.
/// </summary>
/// <param name="packet">Initial Packet</param>
/// <param name="endPoint">Peer's endpoint</param>
/// <returns></returns>
private QuicConnection ProcessInitialPacket(Packet packet, IPEndPoint endPoint)
{
QuicConnection result = null;
UInt32 availableConnectionId;
byte[] data;
// Unsupported version. Version negotiation packet is sent only on initial connection. All other packets are dropped. (5.2.2 / 16th draft)
if (packet.Version != QuicVersion.CurrentVersion || !QuicVersion.SupportedVersions.Contains(packet.Version))
{
VersionNegotiationPacket vnp = _packetCreator.CreateVersionNegotiationPacket();
data = vnp.Encode();
_client.Send(data, data.Length, endPoint);
return(null);
}
InitialPacket cast = packet as InitialPacket;
InitialPacket ip = _packetCreator.CreateInitialPacket(0, cast.SourceConnectionId);
// Protocol violation if the initial packet is smaller than the PMTU. (pt. 14 / 16th draft)
if (cast.Encode().Length < QuicSettings.PMTU)
{
ip.AttachFrame(new ConnectionCloseFrame(ErrorCode.PROTOCOL_VIOLATION, "PMTU have not been reached."));
}
else if (ConnectionPool.AddConnection(new ConnectionData(_pwt, cast.SourceConnectionId, 0), out availableConnectionId) == true)
{
// Tell the peer the available connection id
ip.SourceConnectionId = (byte)availableConnectionId;
// We're including the maximum possible stream id during the connection handshake. (4.5 / 16th draft)
ip.AttachFrame(new MaxStreamsFrame(QuicSettings.MaximumStreamId, StreamType.ServerBidirectional));
// Set the return result
result = ConnectionPool.Find(availableConnectionId);
}
else
{
// Not accepting connections. Send initial packet with CONNECTION_CLOSE frame.
// TODO: Buffering. The server might buffer incomming 0-RTT packets in anticipation of late delivery InitialPacket.
// Maximum buffer size should be set in QuicSettings.
ip.AttachFrame(new ConnectionCloseFrame(ErrorCode.SERVER_BUSY, "The server is too busy to process your request."));
}
data = ip.Encode();
int dataSent = _client.Send(data, data.Length, endPoint);
if (dataSent > 0)
{
return(result);
}
return(null);
}
public InitialPacket CreateInitialPacket(GranularInteger sourceConnectionId, GranularInteger destinationConnectionId)
{
InitialPacket packet = new InitialPacket(destinationConnectionId, sourceConnectionId);
packet.PacketNumber = 0;
packet.SourceConnectionId = sourceConnectionId;
packet.DestinationConnectionId = destinationConnectionId;
packet.Version = QuicVersion.CurrentVersion;
int length = packet.Encode().Length;
int padding = QuicSettings.PMTU - length;
for (int i = 0; i < padding; i++)
{
packet.AttachFrame(new PaddingFrame());
}
return(packet);
}
public InitialPacket CreateInitialPacket(byte sourceConnectionId, byte destinationConnectionId)
{
var packet = new InitialPacket
{
PacketNumber = 0,
SourceConnectionId = sourceConnectionId,
DestinationConnectionId = destinationConnectionId,
Version = QuicVersion.CurrentVersion
};
var length = packet.Encode().Length;
var padding = QuicSettings.PMTU - length;
for (var i = 0; i < padding; i++)
{
packet.AttachFrame(new PaddingFrame());
}
return(packet);
}
