// sends a connection challenge packet to the endpoint
private void sendConnectionChallenge(NetcodePrivateConnectToken connectToken, EndPoint endpoint)
{
log("Sending connection challenge", NetcodeLogLevel.Debug);
var challengeToken = new NetcodeChallengeToken();
challengeToken.ClientID = connectToken.ClientID;
challengeToken.UserData = connectToken.UserData;
ulong challengeSequence = nextChallengeSequenceNumber++;
byte[] tokenBytes = BufferPool.GetBuffer(300);
using (var tokenWriter = ByteArrayReaderWriter.Get(tokenBytes))
challengeToken.Write(tokenWriter);
byte[] encryptedToken = BufferPool.GetBuffer(300);
int encryptedTokenBytes;
try
{
encryptedTokenBytes = PacketIO.EncryptChallengeToken(challengeSequence, tokenBytes, challengeKey, encryptedToken);
}
catch
{
BufferPool.ReturnBuffer(tokenBytes);
BufferPool.ReturnBuffer(encryptedToken);
return;
}
var challengePacket = new NetcodeConnectionChallengeResponsePacket();
challengePacket.ChallengeTokenSequence = challengeSequence;
challengePacket.ChallengeTokenBytes = encryptedToken;
var cryptIdx = encryptionManager.FindEncryptionMapping(endpoint, time);
if (cryptIdx == -1)
{
return;
}
var cryptKey = encryptionManager.GetSendKey(cryptIdx);
serializePacket(new NetcodePacketHeader()
{
PacketType = NetcodePacketType.ConnectionChallenge
}, (writer) =>
{
challengePacket.Write(writer);
}, endpoint, cryptKey);
BufferPool.ReturnBuffer(tokenBytes);
BufferPool.ReturnBuffer(encryptedToken);
}
private void processChallengePacket(NetcodePacketHeader header, int length, ByteArrayReaderWriter stream)
{
var decryptKey = serverToClientKey;
var challengePacket = new NetcodeConnectionChallengeResponsePacket()
{
Header = header
};
if (!challengePacket.Read(stream, length, decryptKey, connectToken.ProtocolID))
{
return;
}
if (state == ClientState.SendingConnectionRequest)
{
this.challengeResponse = challengePacket;
this.challengeResponse.Header.PacketType = NetcodePacketType.ChallengeResponse;
// move onto sending challenge response
timer = 0.0;
connectionTimer = 0.0;
changeState(ClientState.SendingChallengeResponse);
}
}
// process an incoming connection response packet
private void processConnectionResponse(ByteArrayReaderWriter reader, NetcodePacketHeader header, int size, EndPoint sender)
{
log("Got connection response", NetcodeLogLevel.Debug);
// encryption mapping was not registered, so don't bother
int cryptIdx = encryptionManager.FindEncryptionMapping(sender, time);
if (cryptIdx == -1)
{
log("No crytpo key for sender", NetcodeLogLevel.Debug);
return;
}
// grab the decryption key and decrypt the packet
var decryptKey = encryptionManager.GetReceiveKey(cryptIdx);
var connectionResponsePacket = new NetcodeConnectionChallengeResponsePacket()
{
Header = header
};
if (!connectionResponsePacket.Read(reader, size - (int)reader.ReadPosition, decryptKey, protocolID))
{
log("Failed to decrypt packet", NetcodeLogLevel.Debug);
return;
}
var challengeToken = new NetcodeChallengeToken();
if (!challengeToken.Read(connectionResponsePacket.ChallengeTokenBytes, connectionResponsePacket.ChallengeTokenSequence, challengeKey))
{
log("Failed to read challenge token", NetcodeLogLevel.Debug);
connectionResponsePacket.Release();
return;
}
// if a client from packet source IP / port is already connected, ignore the packet
if (clientSlots.Any(x => x != null && x.RemoteEndpoint.Equals(sender)))
{
log("Client {0} already connected", NetcodeLogLevel.Debug, sender.ToString());
return;
}
// if a client with the same id is already connected, ignore the packet
if (clientSlots.Any(x => x != null && x.ClientID == challengeToken.ClientID))
{
log("Client ID {0} already connected", NetcodeLogLevel.Debug, challengeToken.ClientID);
return;
}
// if the server is full, deny the connection
int nextSlot = getFreeClientSlot();
if (nextSlot == -1)
{
log("Server full, denying connection", NetcodeLogLevel.Info);
denyConnection(sender, encryptionManager.GetSendKey(cryptIdx));
return;
}
// assign the endpoint and client ID to a free client slot and set connected to true
RemoteClient client = new RemoteClient(this);
client.ClientID = challengeToken.ClientID;
client.RemoteEndpoint = sender;
client.Connected = true;
client.replayProtection = new NetcodeReplayProtection();
// assign timeout to client
client.timeoutSeconds = encryptionManager.GetTimeoutSeconds(cryptIdx);
// assign client to a free slot
client.ClientIndex = (uint)nextSlot;
this.clientSlots[nextSlot] = client;
encryptionManager.SetClientID(cryptIdx, client.ClientIndex);
// copy user data so application can make use of it, and set confirmed to false
client.UserData = challengeToken.UserData;
client.Confirmed = false;
client.Touch(time);
// respond with a connection keep alive packet
sendKeepAlive(client);
}