core

type Connection interface {
	// RemoteAddr returns the destination network address.
	RemoteAddr() net.Addr

	// LocalAddr returns the local client network address.
	LocalAddr() net.Addr

	// Receive receives data from TUN.
	Receive(data []byte) error

	// Write writes data to TUN.
	Write(data []byte) (int, error)

	// Sent will be called when sent data has been acknowledged by clients (TCP only).
	Sent(len uint16) error

	// Close closes the connection (TCP only).
	Close() error

	// Abort aborts the connection to client by sending a RST segment (TCP only).
	Abort()

	// Err will be called when a fatal error has occurred on the connection (TCP only).
	Err(err error)

	// LocalDidClose will be called when local client has close the connection (TCP only).
	LocalDidClose() error

	// Poll will be periodically called by timers (TCP only).
	Poll() error
}

type ConnectionHandler interface {
	// Connect connects the proxy server.
	Connect(conn Connection, target net.Addr) error

	// DidReceive will be called when data arrives from TUN.
	DidReceive(conn Connection, data []byte) error

	// DidSend will be called when sent data has been acknowledged by local clients.
	DidSend(conn Connection, len uint16)

	// DidClose will be called when the connection has been closed.
	DidClose(conn Connection)

	// LocalDidClose will be called when local client has close the connection.
	LocalDidClose(conn Connection)
}

type LWIPStack interface {
	Write([]byte) (int, error)
	Close() error
	RestartTimeouts()
}