add buffer size option for udp connection

connector/socks/v5/conn.go

@@ -2,10 +2,10 @@ package v5
 
 import (
 	"bytes"
-	"math"
 	"net"
 	"time"
 
+	"github.com/go-gost/core/common/bufpool"
 	"github.com/go-gost/core/logger"
 	"github.com/go-gost/gosocks5"
 )
@@ -25,17 +25,18 @@ func (c *bindConn) RemoteAddr() net.Addr {
 }
 
 type udpRelayConn struct {
-	udpConn *net.UDPConn
-	tcpConn net.Conn
-	taddr   net.Addr
-	rbuf    [math.MaxUint16]byte
-	wbuf    [math.MaxInt16]byte
-	logger  logger.Logger
+	udpConn    *net.UDPConn
+	tcpConn    net.Conn
+	taddr      net.Addr
+	bufferSize int
+	logger     logger.Logger
 }
 
 func (c *udpRelayConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
-	buf := c.rbuf[:]
-	nn, err := c.udpConn.Read(buf[:])
+	buf := bufpool.Get(c.bufferSize)
+	defer bufpool.Put(buf)
+
+	nn, err := c.udpConn.Read(buf)
 	if err != nil {
 		return
 	}
@@ -81,7 +82,8 @@ func (c *udpRelayConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
 		Data:   b,
 	}
 
-	buf := c.wbuf[:]
+	buf := bufpool.Get(c.bufferSize)
+	defer bufpool.Put(buf)
 
 	nn, err := dgram.WriteTo(bytes.NewBuffer(buf[:0]))
 	if err != nil {

connector/socks/v5/connector.go

@@ -225,9 +225,10 @@ func (c *socks5Connector) relayUDP(ctx context.Context, conn net.Conn, addr net.
 	}
 
 	return &udpRelayConn{
-		udpConn: cc.(*net.UDPConn),
-		tcpConn: conn,
-		taddr:   addr,
-		logger:  log,
+		udpConn:    cc.(*net.UDPConn),
+		tcpConn:    conn,
+		taddr:      addr,
+		bufferSize: c.md.udpBufferSize,
+		logger:     log,
 	}, nil
 }

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{