add buffer size option for udp connection

connector/ss/udp/connector.go

@@ -85,7 +85,7 @@ func (c *ssuConnector) Connect(ctx context.Context, conn net.Conn, network, addr
 		}
 
 		// standard UDP relay
-		return ss.UDPClientConn(pc, conn.RemoteAddr(), taddr), nil
+		return ss.UDPClientConn(pc, conn.RemoteAddr(), taddr, c.md.udpBufferSize), nil
 	}
 
 	if c.cipher != nil {

connector/ss/udp/metadata.go

@@ -10,16 +10,13 @@ import (
 type metadata struct {
 	key            string
 	connectTimeout time.Duration
+	udpBufferSize  int
 }
 
 func (c *ssuConnector) parseMetadata(md mdata.Metadata) (err error) {
-	const (
-		key            = "key"
-		connectTimeout = "timeout"
-	)
-
-	c.md.key = mdutil.GetString(md, key)
-	c.md.connectTimeout = mdutil.GetDuration(md, connectTimeout)
+	c.md.key = mdutil.GetString(md, "key")
+	c.md.connectTimeout = mdutil.GetDuration(md, "timeout", "connectTimeout")
+	c.md.udpBufferSize = mdutil.GetInt(md, "udpBufferSize", "udp.bufferSize")
 
 	return
 }