public override int FindSlot(IPEndPoint endPoint, bool comparePorts)
{
for (var i = 0; i < Connections.Length; i++)
{
if (Connections[i].State != ConnectionState.OFFLINE &&
Connections[i].State != ConnectionState.ERROR &&
NetworkCore.CompareEndPoints(Connections[i].EndPoint, endPoint, comparePorts))
{
return(i);
}
}
return(-1);
}
public override bool Receive(out NetworkChunk packet)
{
while (true)
{
if (ChunkReceiver.FetchChunk(out packet))
{
return(true);
}
if (UdpClient.Available <= 0)
{
return(false);
}
var remote = (IPEndPoint)null;
byte[] data;
try
{
data = UdpClient.Receive(ref remote);
}
catch
{
continue;
}
if (data.Length <= 0)
{
continue;
}
if (!NetworkCore.UnpackPacket(data, data.Length, ChunkReceiver.ChunkConstruct))
{
continue;
}
var useToken = false;
var token = (uint)0;
if (ChunkReceiver.ChunkConstruct.Flags.HasFlag(PacketFlags.TOKEN))
{
useToken = true;
token = ChunkReceiver.ChunkConstruct.Token;
}
else if (ChunkReceiver.ChunkConstruct.Flags.HasFlag(PacketFlags.CONTROL) &&
ChunkReceiver.ChunkConstruct.Data[0] == (int)ConnectionMessages.CONNECT &&
ChunkReceiver.ChunkConstruct.DataSize >= 1 + 512)
{
useToken = true;
token = ChunkReceiver.ChunkConstruct.Data.ToUInt32(5);
}
if (NetworkBan.IsBanned(remote, out var reason))
{
NetworkCore.SendControlMsg(UdpClient, remote, 0, useToken, token,
ConnectionMessages.CLOSE, reason);
continue;
}
if (ChunkReceiver.ChunkConstruct.Flags.HasFlag(PacketFlags.CONNLESS))
{
packet = new NetworkChunk
{
ClientId = -1,
Flags = SendFlags.CONNLESS,
EndPoint = remote,
DataSize = ChunkReceiver.ChunkConstruct.DataSize,
Data = ChunkReceiver.ChunkConstruct.Data
};
return(true);
}
var clientId = FindSlot(remote, true);
if (ChunkReceiver.ChunkConstruct.Flags.HasFlag(PacketFlags.CONTROL) &&
ChunkReceiver.ChunkConstruct.Data[0] == (int)ConnectionMessages.CONNECT)
{
if (clientId != -1)
{
continue;
}
if (ChunkReceiver.ChunkConstruct.DataSize >= 1 + 512)
{
var connectAccept = new byte[4];
GetToken(remote).ToByteArray(connectAccept, 0);
NetworkCore.SendControlMsg(UdpClient, remote, 0, true, token,
ConnectionMessages.CONNECTACCEPT, connectAccept);
Debug.Log("netserver", "got connect, sending connect+accept challenge");
}
else if (Config["SvAllowOldClients"].AsBoolean() && string.IsNullOrWhiteSpace(Config["Password"].AsString()))
{
if (LegacyRateLimit())
{
Debug.Log("netserver", "dropping legacy connect due to ratelimit");
continue;
}
var packets = new NetworkChunkConstruct[]
{
new NetworkChunkConstruct(),
new NetworkChunkConstruct(),
};
var legacyToken = GetLegacyToken(remote);
ConstructLegacyHandshake(packets[0], packets[1], legacyToken);
for (var i = 0; i < 2; i++)
{
NetworkCore.SendPacket(UdpClient, remote, packets[i]);
}
Debug.Log("netserver", "got legacy connect, sending legacy challenge");
}
else
{
Debug.Log("netserver", $"dropping short connect packet, size={ChunkReceiver.ChunkConstruct.DataSize}");
}
}
else
{
if (clientId == -1)
{
if (!useToken || !IsCorrectToken(remote, token))
{
if (!useToken && Config["SvAllowOldClients"].AsBoolean())
{
ChunkReceiver.Start(remote, null, -1);
var chunk = new NetworkChunk();
var correct = false;
while (ChunkReceiver.FetchChunk(out chunk))
{
if (DecodeLegacyHandShake(chunk.Data, chunk.DataSize, out var legacyToken))
{
if (IsCorrectLegacyToken(remote, legacyToken))
{
correct = true;
break;
}
}
}
ChunkReceiver.Clear();
if (!correct)
{
continue;
}
}
else
{
Debug.Log("netserver",
!useToken
? "dropping packet with missing token"
: $"dropping packet with invalid token, token={token}");
continue;
}
}
var sameIps = 0;
for (var i = 0; i < Connections.Length; i++)
{
if (Connections[i].State == ConnectionState.OFFLINE)
{
if (clientId < 0)
{
clientId = i;
}
continue;
}
if (!NetworkCore.CompareEndPoints(Connections[i].EndPoint, remote, false))
{
continue;
}
sameIps++;
if (sameIps >= ServerConfig.MaxClientsPerIp)
{
NetworkCore.SendControlMsg(UdpClient, remote, 0, useToken, token, ConnectionMessages.CLOSE,
$"Only {ServerConfig.MaxClientsPerIp} players with the same IP are allowed");
return(false);
}
}
if (clientId < 0)
{
for (var i = 0; i < Connections.Length; i++)
{
if (Connections[i].State == ConnectionState.OFFLINE)
{
clientId = i;
break;
}
}
}
if (clientId < 0)
{
NetworkCore.SendControlMsg(UdpClient, remote, 0, useToken, token,
ConnectionMessages.CLOSE, "This server is full");
return(false);
}
if (useToken)
{
Connections[clientId].Accept(remote, token);
}
else
{
Connections[clientId].AcceptLegacy(remote);
}
NewClientCallback?.Invoke(clientId, !useToken);
if (!useToken)
{
continue;
}
Connections[clientId].Feed(ChunkReceiver.ChunkConstruct, remote);
}
if (Connections[clientId].Feed(ChunkReceiver.ChunkConstruct, remote))
{
if (ChunkReceiver.ChunkConstruct.DataSize != 0)
{
ChunkReceiver.Start(remote, Connections[clientId], clientId);
}
}
}
}
}
public override bool Feed(NetworkChunkConstruct packet, IPEndPoint remote)
{
if (packet.Flags.HasFlag(PacketFlags.RESEND))
{
Resend();
}
if (UseToken)
{
if (!packet.Flags.HasFlag(PacketFlags.TOKEN))
{
if (!packet.Flags.HasFlag(PacketFlags.CONTROL) || packet.DataSize < 1)
{
Debug.Log("connection", "dropping msg without token");
return(false);
}
if (packet.Data[0] == (int)ConnectionMessages.CONNECTACCEPT)
{
if (!Config["ClAllowOldServers"])
{
Debug.Log("connection", "dropping connect+accept without token");
return(false);
}
}
else
{
Debug.Log("connection", "dropping ctrl msg without token");
return(false);
}
}
else
{
if (packet.Token != Token)
{
Debug.Log("connection", $"dropping msg with invalid token, wanted={Token} got={packet.Token}");
return(false);
}
}
}
if (Sequence >= PeerAck)
{
if (packet.Ack < PeerAck || packet.Ack > Sequence)
{
return(false);
}
}
else
{
if (packet.Ack < PeerAck && packet.Ack > Sequence)
{
return(false);
}
}
PeerAck = packet.Ack;
if (packet.Flags.HasFlag(PacketFlags.RESEND))
{
Resend();
}
if (packet.Flags.HasFlag(PacketFlags.CONTROL))
{
var msg = (ConnectionMessages)packet.Data[0];
if (msg == ConnectionMessages.CLOSE)
{
if (!NetworkCore.CompareEndPoints(EndPoint, remote, true))
{
return(false);
}
State = ConnectionState.ERROR;
RemoteClosed = true;
var reason = "";
if (packet.DataSize > 1)
{
reason = Encoding.UTF8.GetString(packet.Data, 1, Math.Clamp(packet.DataSize - 1, 1, 128));
}
Error = reason;
Debug.Log("connection", $"closed reason='{reason}'");
return(false);
}
else
{
if (State == ConnectionState.CONNECT)
{
if (msg == ConnectionMessages.CONNECTACCEPT)
{
if (packet.Flags.HasFlag(PacketFlags.TOKEN))
{
if (packet.DataSize < 1 + 4)
{
Debug.Log("connection", $"got short connect+accept, size={packet.DataSize}");
return(true);
}
Token = packet.Data.ToUInt32(1);
}
else
{
UseToken = false;
}
LastReceiveTime = Time.Get();
State = ConnectionState.ONLINE;
Debug.Log("connection", "got connect+accept, sending accept. connection online");
}
}
}
}
if (State == ConnectionState.ONLINE)
{
LastReceiveTime = Time.Get();
AckChunks(packet.Ack);
}
return(true);
}