chore: listening tcp together for dns server (#1792)

common/sockopt/reuse_common.go

@@ -0,0 +1,30 @@
+package sockopt
+
+import (
+	"net"
+	"syscall"
+)
+
+func RawConnReuseaddr(rc syscall.RawConn) (err error) {
+	var innerErr error
+	err = rc.Control(func(fd uintptr) {
+		innerErr = reuseControl(fd)
+	})
+
+	if innerErr != nil {
+		err = innerErr
+	}
+	return
+}
+
+func UDPReuseaddr(c net.PacketConn) error {
+	if c, ok := c.(syscall.Conn); ok {
+		rc, err := c.SyscallConn()
+		if err != nil {
+			return err
+		}
+
+		return RawConnReuseaddr(rc)
+	}
+	return nil
+}

common/sockopt/reuse_other.go

@@ -0,0 +1,5 @@
+//go:build !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !solaris && !windows
+
+package sockopt
+
+func reuseControl(fd uintptr) error { return nil }

common/sockopt/reuse_unix.go

@@ -0,0 +1,22 @@
+//go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
+
+package sockopt
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+func reuseControl(fd uintptr) error {
+	e1 := unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_REUSEADDR, 1)
+	e2 := unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_REUSEPORT, 1)
+
+	if e1 != nil {
+		return e1
+	}
+
+	if e2 != nil {
+		return e2
+	}
+
+	return nil
+}

common/sockopt/reuse_windows.go

@@ -0,0 +1,9 @@
+package sockopt
+
+import (
+	"golang.org/x/sys/windows"
+)
+
+func reuseControl(fd uintptr) error {
+	return windows.SetsockoptInt(windows.Handle(fd), windows.SOL_SOCKET, windows.SO_REUSEADDR, 1)
+}

common/sockopt/reuseaddr_linux.go

@@ -1,19 +0,0 @@
-package sockopt
-
-import (
-	"net"
-	"syscall"
-)
-
-func UDPReuseaddr(c *net.UDPConn) (err error) {
-	rc, err := c.SyscallConn()
-	if err != nil {
-		return
-	}
-
-	rc.Control(func(fd uintptr) {
-		err = syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
-	})
-
-	return
-}

common/sockopt/reuseaddr_other.go

@@ -1,11 +0,0 @@
-//go:build !linux
-
-package sockopt
-
-import (
-	"net"
-)
-
-func UDPReuseaddr(c *net.UDPConn) (err error) {
-	return
-}