stack allocated buffer

common/protocol/address.go

@@ -2,11 +2,13 @@ package protocol
 
 import (
 	"io"
+	"unsafe"
 
 	"v2ray.com/core/common"
 	"v2ray.com/core/common/buf"
 	"v2ray.com/core/common/net"
 	"v2ray.com/core/common/serial"
+	"v2ray.com/core/common/stack"
 )
 
 type AddressOption func(*option)
@@ -232,7 +234,13 @@ func (p *addressParser) writeAddress(writer io.Writer, address net.Address) erro
 
 	switch address.Family() {
 	case net.AddressFamilyIPv4, net.AddressFamilyIPv6:
-		if _, err := writer.Write([]byte{tb}); err != nil {
+		var bytes stack.TwoBytes
+		s := bytes[:1]
+		s[0] = tb
+		p := uintptr(unsafe.Pointer(&s))
+		v := (*[]byte)(unsafe.Pointer(p))
+
+		if _, err := writer.Write(*v); err != nil {
 			return err
 		}
 		if _, err := writer.Write(address.IP()); err != nil {
@@ -243,7 +251,15 @@ func (p *addressParser) writeAddress(writer io.Writer, address net.Address) erro
 		if isDomainTooLong(domain) {
 			return newError("Super long domain is not supported: ", domain)
 		}
-		if _, err := writer.Write([]byte{tb, byte(len(domain))}); err != nil {
+
+		var bytes stack.TwoBytes
+		s := bytes[:]
+		s[0] = tb
+		s[1] = byte(len(domain))
+		p := uintptr(unsafe.Pointer(&s))
+		v := (*[]byte)(unsafe.Pointer(p))
+
+		if _, err := writer.Write(*v); err != nil {
 			return err
 		}
 		if _, err := io.WriteString(writer, domain); err != nil {

common/stack/bytes.go

@@ -0,0 +1,11 @@
+package stack
+
+// TwoBytes is a [8]byte which is always allocated on stack.
+//
+//go:notinheap
+type TwoBytes [2]byte
+
+// EightBytes is a [8]byte which is always allocated on stack.
+//
+//go:notinheap
+type EightBytes [8]byte