新增dnst隧道

listener/dns/tunnel.go

@@ -3,6 +3,7 @@ package dns
 import (
 	"context"
 	"crypto/tls"
+	"errors"
 	"net"
 	"strings"
 
@@ -65,6 +66,7 @@ func (l *dnsTunnelListener) Init(md md.Metadata) (err error) {
 	if err != nil {
 		return
 	}
+	bufferConn := conn
 
 	conn = dns_util.ServerConn(
 		conn,
@@ -82,6 +84,10 @@ func (l *dnsTunnelListener) Init(md md.Metadata) (err error) {
 		limiter.ServiceOption(l.options.Service),
 		limiter.NetworkOption(conn.LocalAddr().Network()),
 	)
+	conn = &setBufferPacketConn{
+		PacketConn: conn,
+		bufferConn: bufferConn,
+	}
 
 	config := &quic.Config{
 		KeepAlivePeriod:      l.md.keepAlivePeriod,
@@ -203,3 +209,22 @@ func (c *dnsTunnelConn) LocalAddr() net.Addr {
 func (c *dnsTunnelConn) RemoteAddr() net.Addr {
 	return c.raddr
 }
+
+type setBufferPacketConn struct {
+	net.PacketConn
+	bufferConn net.PacketConn
+}
+
+func (c *setBufferPacketConn) SetReadBuffer(n int) error {
+	if pc, ok := c.bufferConn.(interface{ SetReadBuffer(int) error }); ok {
+		return pc.SetReadBuffer(n)
+	}
+	return errors.New("dns: set read buffer unsupported")
+}
+
+func (c *setBufferPacketConn) SetWriteBuffer(n int) error {
+	if pc, ok := c.bufferConn.(interface{ SetWriteBuffer(int) error }); ok {
+		return pc.SetWriteBuffer(n)
+	}
+	return errors.New("dns: set write buffer unsupported")
+}