Send shadowsocks handshake with payload if available (#736)

proxy/shadowsocks/client.go

@@ -2,6 +2,7 @@ package shadowsocks
 
 import (
 	"context"
+	"time"
 
 	"github.com/xtls/xray-core/transport/internet/stat"
 
@@ -101,18 +102,22 @@ func (c *Client) Process(ctx context.Context, link *transport.Link, dialer inter
 	timer := signal.CancelAfterInactivity(ctx, cancel, sessionPolicy.Timeouts.ConnectionIdle)
 
 	if request.Command == protocol.RequestCommandTCP {
+		requestDone := func() error {
+			defer timer.SetTimeout(sessionPolicy.Timeouts.DownlinkOnly)
 			bufferedWriter := buf.NewBufferedWriter(buf.NewWriter(conn))
 			bodyWriter, err := WriteTCPRequest(request, bufferedWriter)
 			if err != nil {
 				return newError("failed to write request").Base(err)
 			}
 
+			if err = buf.CopyOnceTimeout(link.Reader, bodyWriter, time.Millisecond*100); err != nil && err != buf.ErrNotTimeoutReader && err != buf.ErrReadTimeout {
+				return newError("failed to write A request payload").Base(err).AtWarning()
+			}
+
 			if err := bufferedWriter.SetBuffered(false); err != nil {
 				return err
 			}
 
-		requestDone := func() error {
-			defer timer.SetTimeout(sessionPolicy.Timeouts.DownlinkOnly)
 			return buf.Copy(link.Reader, bodyWriter, buf.UpdateActivity(timer))
 		}