add buffer size option for udp connection

handler/ss/udp/handler.go

@@ -7,6 +7,7 @@ import (
 	"net"
 	"time"
 
+	"github.com/go-gost/core/common/bufpool"
 	"github.com/go-gost/core/handler"
 	"github.com/go-gost/core/logger"
 	md "github.com/go-gost/core/metadata"
@@ -112,7 +113,7 @@ func (h *ssuHandler) Handle(ctx context.Context, conn net.Conn, opts ...handler.
 			pc = h.cipher.PacketConn(pc)
 		}
 		// standard UDP relay.
-		pc = ss.UDPServerConn(pc, conn.RemoteAddr())
+		pc = ss.UDPServerConn(pc, conn.RemoteAddr(), h.md.udpBufferSize)
 	} else {
 		if h.cipher != nil {
 			conn = ss.ShadowConn(h.cipher.StreamConn(conn), nil)
@@ -150,11 +151,18 @@ func (h *ssuHandler) Handle(ctx context.Context, conn net.Conn, opts ...handler.
 func (h *ssuHandler) relayPacket(ctx context.Context, pc1, pc2 net.PacketConn, ro *xrecorder.HandlerRecorderObject, log logger.Logger) (err error) {
 	errc := make(chan error, 2)
 
+	bufferSize := h.md.udpBufferSize
+	if bufferSize <= 0 {
+		bufferSize = defaultBufferSize
+	}
+
 	go func() {
-		var b [MaxMessageSize]byte
+		b := bufpool.Get(bufferSize)
+		defer bufpool.Put(b)
+
 		for {
 			err := func() error {
-				n, addr, err := pc1.ReadFrom(b[:])
+				n, addr, err := pc1.ReadFrom(b)
 				if err != nil {
 					return err
 				}
@@ -185,10 +193,12 @@ func (h *ssuHandler) relayPacket(ctx context.Context, pc1, pc2 net.PacketConn, r
 	}()
 
 	go func() {
-		var b [MaxMessageSize]byte
+		b := bufpool.Get(bufferSize)
+		defer bufpool.Put(b)
+
 		for {
 			err := func() error {
-				n, raddr, err := pc2.ReadFrom(b[:])
+				n, raddr, err := pc2.ReadFrom(b)
 				if err != nil {
 					return err
 				}

handler/ss/udp/metadata.go

@@ -1,7 +1,6 @@
 package ss
 
 import (
-	"math"
 	"time"
 
 	mdata "github.com/go-gost/core/metadata"
@@ -9,22 +8,20 @@ import (
 )
 
 const (
-	MaxMessageSize = math.MaxUint16
+	defaultBufferSize = 4096
 )
 
 type metadata struct {
-	key         string
-	readTimeout time.Duration
+	key           string
+	readTimeout   time.Duration
+	udpBufferSize int
 }
 
 func (h *ssuHandler) parseMetadata(md mdata.Metadata) (err error) {
-	const (
-		key         = "key"
-		readTimeout = "readTimeout"
-	)
 
-	h.md.key = mdutil.GetString(md, key)
-	h.md.readTimeout = mdutil.GetDuration(md, readTimeout)
+	h.md.key = mdutil.GetString(md, "key")
+	h.md.readTimeout = mdutil.GetDuration(md, "readTimeout")
+	h.md.udpBufferSize = mdutil.GetInt(md, "udpBufferSize", "udp.bufferSize")
 
 	return
 }