add buffer size option for udp connection

connector/socks/v5/metadata.go

@@ -8,10 +8,15 @@ import (
 	mdutil "github.com/go-gost/x/metadata/util"
 )
 
+const (
+	defaultUDPBufferSize = 4096
+)
+
 type metadata struct {
 	connectTimeout time.Duration
 	noTLS          bool
 	relay          string
+	udpBufferSize  int
 	udpTimeout     time.Duration
 	muxCfg         *mux.Config
 }
@@ -20,6 +25,10 @@ func (c *socks5Connector) parseMetadata(md mdata.Metadata) (err error) {
 	c.md.connectTimeout = mdutil.GetDuration(md, "timeout")
 	c.md.noTLS = mdutil.GetBool(md, "notls")
 	c.md.relay = mdutil.GetString(md, "relay")
+	c.md.udpBufferSize = mdutil.GetInt(md, "udp.bufferSize", "udpBufferSize")
+	if c.md.udpBufferSize <= 0 {
+		c.md.udpBufferSize = defaultUDPBufferSize
+	}
 	c.md.udpTimeout = mdutil.GetDuration(md, "udp.timeout")
 
 	c.md.muxCfg = &mux.Config{