Use Buffer as a writer

common/alloc/buffer.go

@@ -50,6 +50,11 @@ func (b *Buffer) IsFull() bool {
 	return len(b.Value) == cap(b.Value)
 }
 
+func (b *Buffer) Write(data []byte) (int, error) {
+	b.Append(data)
+	return len(data), nil
+}
+
 type bufferPool struct {
 	chain        chan []byte
 	bufferSize   int
@@ -98,7 +103,10 @@ func (p *bufferPool) cleanup(tick <-chan time.Time) {
 			continue
 		}
 		for delta := p.buffers2Keep - pSize; delta > 0; delta-- {
-			p.chain <- make([]byte, p.bufferSize)
+			select {
+			case p.chain <- make([]byte, p.bufferSize):
+			default:
+			}
 		}
 	}
 }

proxy/vmess/vmessin_udp.go

@@ -77,7 +77,8 @@ func (handler *VMessInboundHandler) handlePacket(conn *net.UDPConn, request *pro
 	responseKey := md5.Sum(request.RequestKey)
 	responseIV := md5.Sum(request.RequestIV)
 
-	buffer := bytes.NewBuffer(make([]byte, 0, bufferSize))
+	buffer := alloc.NewBuffer().Clear()
+	defer buffer.Release()
 
 	responseWriter, err := v2io.NewAesEncryptWriter(responseKey[:], responseIV[:], buffer)
 	if err != nil {
@@ -95,7 +96,7 @@ func (handler *VMessInboundHandler) handlePacket(conn *net.UDPConn, request *pro
 	}
 
 	if hasData {
-		conn.WriteToUDP(buffer.Bytes(), clientAddr)
-		log.Info("VMessIn sending %d bytes to %s", len(buffer.Bytes()), clientAddr.String())
+		conn.WriteToUDP(buffer.Value, clientAddr)
+		log.Info("VMessIn sending %d bytes to %s", buffer.Len(), clientAddr.String())
 	}
 }