cloudflared-mirror/socks/connection_handler.go

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2020-03-31 14:56:22 +00:00
package socks
import (
"bufio"
"fmt"
"io"
)
// ConnectionHandler is the Serve method to handle connections
// from a local TCP listener of the standard library (net.Listener)
type ConnectionHandler interface {
Serve(io.ReadWriter) error
}
// StandardConnectionHandler is the base implementation of handling SOCKS5 requests
type StandardConnectionHandler struct {
requestHandler RequestHandler
authHandler AuthHandler
}
// NewConnectionHandler creates a standard SOCKS5 connection handler
// This process connections from a generic TCP listener from the standard library
func NewConnectionHandler(requestHandler RequestHandler) ConnectionHandler {
return &StandardConnectionHandler{
requestHandler: requestHandler,
authHandler: NewAuthHandler(),
}
}
// Serve process new connection created after calling `Accept()` in the standard library
func (h *StandardConnectionHandler) Serve(c io.ReadWriter) error {
bufConn := bufio.NewReader(c)
// read the version byte
version := []byte{0}
if _, err := bufConn.Read(version); err != nil {
return err
}
// ensure compatibility
if version[0] != socks5Version {
return fmt.Errorf("Unsupported SOCKS version: %v", version)
}
// handle auth
if err := h.authHandler.Handle(bufConn, c); err != nil {
return err
}
// process command/request
req, err := NewRequest(bufConn)
if err != nil {
return err
}
return h.requestHandler.Handle(req, c)
}