private TSocket CreateAcceptSocket(IPEndPoint endPoint, SocketFlags flags)
{
int acceptSocketFd = -1;
int port = endPoint.Port;
try
{
bool ipv4 = endPoint.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork;
SocketInterop.Socket(ipv4 ? AF_INET : AF_INET6, SOCK_STREAM, IPPROTO_TCP, blocking: false,
out acceptSocketFd).ThrowOnError();
TSocket acceptSocket = new TSocket(this, acceptSocketFd, flags, _transportOptions);
if (!ipv4)
{
// Kestrel does mapped ipv4 by default.
acceptSocket.SetSocketOption(SOL_IPV6, IPV6_V6ONLY, 0);
}
if (_transportOptions.ReceiveOnIncomingCpu)
{
if (_transportThread.CpuId != -1)
{
if (!acceptSocket.TrySetSocketOption(SOL_SOCKET, SO_INCOMING_CPU, _transportThread.CpuId))
{
_logger.LogWarning($"Cannot enable SO_INCOMING_CPU for {endPoint}");
}
}
}
// Linux: allow bind during linger time
acceptSocket.SetSocketOption(SOL_SOCKET, SO_REUSEADDR, 1);
// Linux: allow concurrent binds and let the kernel do load-balancing
acceptSocket.SetSocketOption(SOL_SOCKET, SO_REUSEPORT, 1);
if ((flags & SocketFlags.DeferAccept) != 0)
{
// Linux: wait up to 1 sec for data to arrive before accepting socket
acceptSocket.SetSocketOption(SOL_TCP, TCP_DEFER_ACCEPT, 1);
}
acceptSocket.ZeroCopyThreshold = LinuxTransportOptions.NoZeroCopy;
if (_transportOptions.ZeroCopy && _transportOptions.ZeroCopyThreshold != LinuxTransportOptions.NoZeroCopy)
{
if (acceptSocket.TrySetSocketOption(SOL_SOCKET, SO_ZEROCOPY, 1))
{
acceptSocket.ZeroCopyThreshold = _transportOptions.ZeroCopyThreshold;
}
}
var bindResult = acceptSocket.TryBind(endPoint);
if (bindResult == PosixResult.EADDRINUSE)
{
throw new AddressInUseException("Address in use.");
}
if (bindResult == PosixResult.EADDRNOTAVAIL)
{
throw new AddressNotAvailableException("Address not available.");
}
bindResult.ThrowOnError();
if (port == 0)
{
// When testing we want the OS to select a free port
port = acceptSocket.GetLocalIPAddress().Port;
}
acceptSocket.Listen(ListenBacklog);
endPoint.Port = port;
return(acceptSocket);
}
catch
{
if (acceptSocketFd != -1)
{
IOInterop.Close(acceptSocketFd);
}
throw;
}
}