add UDP support for reverse proxy tunnel

connector/ss/udp/metadata.go

@@ -27,7 +27,7 @@ func (c *ssuConnector) parseMetadata(md mdata.Metadata) (err error) {
 	if bs := mdutil.GetInt(md, bufferSize); bs > 0 {
 		c.md.bufferSize = int(math.Min(math.Max(float64(bs), 512), 64*1024))
 	} else {
-		c.md.bufferSize = 1500
+		c.md.bufferSize = 4096
 	}
 
 	return