Chore: adjust all udp alloc size

Author: Dreamacro

common/pool/pool.go

@@ -5,6 +5,11 @@ const (
 	// but the maximum packet size of vmess/shadowsocks is about 16 KiB
 	// so define a buffer of 20 KiB to reduce the memory of each TCP relay
 	RelayBufferSize = 20 * 1024
+
+	// RelayBufferSize uses 20KiB, but due to the allocator it will actually
+	// request 32Kib. Most UDPs are smaller than the MTU, and the TUN's MTU
+	// set to 9000, so the UDP Buffer size set to 16Kib
+	UDPBufferSize = 16 * 1024
 )
 
 func Get(size int) []byte {

listener/socks/udp.go

@@ -49,7 +49,7 @@ func NewUDP(addr string, in chan<- *inbound.PacketAdapter) (*UDPListener, error)
 	}
 	go func() {
 		for {
-			buf := pool.Get(pool.RelayBufferSize)
+			buf := pool.Get(pool.UDPBufferSize)
 			n, remoteAddr, err := l.ReadFrom(buf)
 			if err != nil {
 				pool.Put(buf)

listener/tproxy/udp.go

@@ -57,7 +57,7 @@ func NewUDP(addr string, in chan<- *inbound.PacketAdapter) (*UDPListener, error)
 	go func() {
 		oob := make([]byte, 1024)
 		for {
-			buf := pool.Get(pool.RelayBufferSize)
+			buf := pool.Get(pool.UDPBufferSize)
 			n, oobn, _, lAddr, err := c.ReadMsgUDP(buf, oob)
 			if err != nil {
 				pool.Put(buf)

tunnel/connection.go

@@ -39,7 +39,7 @@ func handleUDPToRemote(packet C.UDPPacket, pc C.PacketConn, metadata *C.Metadata
 }
 
 func handleUDPToLocal(packet C.UDPPacket, pc net.PacketConn, key string, fAddr net.Addr) {
-	buf := pool.Get(pool.RelayBufferSize)
+	buf := pool.Get(pool.UDPBufferSize)
 	defer pool.Put(buf)
 	defer natTable.Delete(key)
 	defer pc.Close()