public void Tick()
{
while (socket != null && socket.Poll(0, SelectMode.SelectRead))
{
try
{
int msgLength = socket.ReceiveFrom(rawReceiveBuffer, 0, rawReceiveBuffer.Length, SocketFlags.None, ref newClientEP);
//Log.Info($"KCP: server raw recv {msgLength} bytes = {BitConverter.ToString(buffer, 0, msgLength)}");
// calculate connectionId from endpoint
int connectionId = newClientEP.GetHashCode();
// IMPORTANT: detect if buffer was too small for the received
// msgLength. otherwise the excess data would be
// silently lost.
// (see ReceiveFrom documentation)
if (msgLength <= rawReceiveBuffer.Length)
{
// is this a new connection?
if (!connections.TryGetValue(connectionId, out KcpServerConnection connection))
{
// create a new KcpConnection
connection = new KcpServerConnection(socket, newClientEP, NoDelay, Interval, FastResend, CongestionWindow, SendWindowSize, ReceiveWindowSize);
// DO NOT add to connections yet. only if the first message
// is actually the kcp handshake. otherwise it's either:
// * random data from the internet
// * or from a client connection that we just disconnected
// but that hasn't realized it yet, still sending data
// from last session that we should absolutely ignore.
//
//
// TODO this allocates a new KcpConnection for each new
// internet connection. not ideal, but C# UDP Receive
// already allocated anyway.
//
// expecting a MAGIC byte[] would work, but sending the raw
// UDP message without kcp's reliability will have low
// probability of being received.
//
// for now, this is fine.
// setUp authenticated event that also adds to connections
connection.OnAuthenticated = () =>
{
// only send handshake to client AFTER we received his
// handshake in OnAuthenticated.
// we don't want to reply to random internet messages
// with handshakes each time.
connection.SendHandshake();
// add to connections dict after being authenticated.
connections.Add(connectionId, connection);
Log.Info($"KCP: server added connection({connectionId}): {newClientEP}");
// setUp Data + Disconnected events only AFTER the
// handshake. we don't want to fire OnServerDisconnected
// every time we receive invalid random data from the
// internet.
// setUp data event
connection.OnData = (message) =>
{
// call mirror event
//Log.Info($"KCP: OnServerDataReceived({connectionId}, {BitConverter.ToString(message.Array, message.Offset, message.Count)})");
OnData.Invoke(connectionId, message);
};
// setUp disconnected event
connection.OnDisconnected = () =>
{
// flag for removal
// (can't remove directly because connection is Updated
// and event is called while iterating all connections)
connectionsToRemove.Add(connectionId);
// call mirror event
Log.Info($"KCP: OnServerDisconnected({connectionId})");
OnDisconnected.Invoke(connectionId);
};
// finally, call mirror OnConnected event
Log.Info($"KCP: OnServerConnected({connectionId})");
OnConnected.Invoke(connectionId);
};
// now input the message & tick
// connected event was set Up.
// tick will process the first message and adds the
// connection if it was the handshake.
connection.RawInput(rawReceiveBuffer, msgLength);
connection.Tick();
// again, do not add to connections.
// if the first message wasn't the kcp handshake then
// connection will simply be garbage collected.
}
// existing connection: simply input the message into kcp
else
{
connection.RawInput(rawReceiveBuffer, msgLength);
}
}
else
{
Log.Error($"KCP Server: message of size {msgLength} does not fit into buffer of size {rawReceiveBuffer.Length}. The excess was silently dropped. Disconnecting connectionId={connectionId}.");
Disconnect(connectionId);
}
}
// this is fine, the socket might have been closed in the other end
catch (SocketException) {}
}
// tick all server connections
foreach (KcpServerConnection connection in connections.Values)
{
connection.Tick();
}
// remove disconnected connections
// (can't do it in connection.OnDisconnected because Tick is called
// while iterating connections)
foreach (int connectionId in connectionsToRemove)
{
connections.Remove(connectionId);
}
connectionsToRemove.Clear();
}
public void TickIncoming()
{
while (socket != null && socket.Poll(0, SelectMode.SelectRead))
{
try
{
// NOTE: ReceiveFrom allocates.
// we pass our IPEndPoint to ReceiveFrom.
// receive from calls newClientEP.Create(socketAddr).
// IPEndPoint.Create always returns a new IPEndPoint.
// https://github.com/mono/mono/blob/f74eed4b09790a0929889ad7fc2cf96c9b6e3757/mcs/class/System/System.Net.Sockets/Socket.cs#L1761
//int msgLength = socket.ReceiveFrom(rawReceiveBuffer, 0, rawReceiveBuffer.Length, SocketFlags.None, ref newClientEP);
//Log.Info($"KCP: server raw recv {msgLength} bytes = {BitConverter.ToString(buffer, 0, msgLength)}");
// where-allocation nonalloc ReceiveFrom.
int msgLength = socket.ReceiveFrom_NonAlloc(rawReceiveBuffer, 0, rawReceiveBuffer.Length, SocketFlags.None, reusableClientEP);
SocketAddress remoteAddress = reusableClientEP.temp;
// calculate connectionId from endpoint
// NOTE: IPEndPoint.GetHashCode() allocates.
// it calls m_Address.GetHashCode().
// m_Address is an IPAddress.
// GetHashCode() allocates for IPv6:
// https://github.com/mono/mono/blob/bdd772531d379b4e78593587d15113c37edd4a64/mcs/class/referencesource/System/net/System/Net/IPAddress.cs#L699
//
// => using only newClientEP.Port wouldn't work, because
// different connections can have the same port.
//int connectionId = newClientEP.GetHashCode();
// where-allocation nonalloc GetHashCode
int connectionId = remoteAddress.GetHashCode();
// IMPORTANT: detect if buffer was too small for the received
// msgLength. otherwise the excess data would be
// silently lost.
// (see ReceiveFrom documentation)
if (msgLength <= rawReceiveBuffer.Length)
{
// is this a new connection?
if (!connections.TryGetValue(connectionId, out KcpServerConnection connection))
{
// IPEndPointNonAlloc is reused all the time.
// we can't store that as the connection's endpoint.
// we need a new copy!
IPEndPoint newClientEP = reusableClientEP.DeepCopyIPEndPoint();
// for allocation free sending, we also need another
// IPEndPointNonAlloc...
IPEndPointNonAlloc reusableSendEP = new IPEndPointNonAlloc(newClientEP.Address, newClientEP.Port);
// create a new KcpConnection
// -> where-allocation IPEndPointNonAlloc is reused.
// need to create a new one from the temp address.
connection = new KcpServerConnection(socket, newClientEP, reusableSendEP, NoDelay, Interval, FastResend, CongestionWindow, SendWindowSize, ReceiveWindowSize, Timeout);
// DO NOT add to connections yet. only if the first message
// is actually the kcp handshake. otherwise it's either:
// * random data from the internet
// * or from a client connection that we just disconnected
// but that hasn't realized it yet, still sending data
// from last session that we should absolutely ignore.
//
//
// TODO this allocates a new KcpConnection for each new
// internet connection. not ideal, but C# UDP Receive
// already allocated anyway.
//
// expecting a MAGIC byte[] would work, but sending the raw
// UDP message without kcp's reliability will have low
// probability of being received.
//
// for now, this is fine.
// setup authenticated event that also adds to connections
connection.OnAuthenticated = () =>
{
// only send handshake to client AFTER we received his
// handshake in OnAuthenticated.
// we don't want to reply to random internet messages
// with handshakes each time.
connection.SendHandshake();
// add to connections dict after being authenticated.
connections.Add(connectionId, connection);
Log.Info($"KCP: server added connection({connectionId}): {newClientEP}");
// setup Data + Disconnected events only AFTER the
// handshake. we don't want to fire OnServerDisconnected
// every time we receive invalid random data from the
// internet.
// setup data event
connection.OnData = (message) =>
{
// call mirror event
//Log.Info($"KCP: OnServerDataReceived({connectionId}, {BitConverter.ToString(message.Array, message.Offset, message.Count)})");
OnData.Invoke(connectionId, message);
};
// setup disconnected event
connection.OnDisconnected = () =>
{
// flag for removal
// (can't remove directly because connection is updated
// and event is called while iterating all connections)
connectionsToRemove.Add(connectionId);
// call mirror event
Log.Info($"KCP: OnServerDisconnected({connectionId})");
OnDisconnected.Invoke(connectionId);
};
// finally, call mirror OnConnected event
Log.Info($"KCP: OnServerConnected({connectionId})");
OnConnected.Invoke(connectionId);
};
// now input the message & process received ones
// connected event was set up.
// tick will process the first message and adds the
// connection if it was the handshake.
connection.RawInput(rawReceiveBuffer, msgLength);
connection.TickIncoming();
// again, do not add to connections.
// if the first message wasn't the kcp handshake then
// connection will simply be garbage collected.
}
// existing connection: simply input the message into kcp
else
{
connection.RawInput(rawReceiveBuffer, msgLength);
}
}
else
{
Log.Error($"KCP Server: message of size {msgLength} does not fit into buffer of size {rawReceiveBuffer.Length}. The excess was silently dropped. Disconnecting connectionId={connectionId}.");
Disconnect(connectionId);
}
}
// this is fine, the socket might have been closed in the other end
catch (SocketException) {}
}
// process inputs for all server connections
// (even if we didn't receive anything. need to tick ping etc.)
foreach (KcpServerConnection connection in connections.Values)
{
connection.TickIncoming();
}
// remove disconnected connections
// (can't do it in connection.OnDisconnected because Tick is called
// while iterating connections)
foreach (int connectionId in connectionsToRemove)
{
connections.Remove(connectionId);
}
connectionsToRemove.Clear();
}
