refactor: re-org packages

core/sockopt/sockopt_linux.go

@@ -0,0 +1,22 @@
+package sockopt
+
+import (
+	"net"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+)
+
+func bindRawConn(network string, c syscall.RawConn, bindIface *net.Interface) error {
+	var err1, err2 error
+	err1 = c.Control(func(fd uintptr) {
+		if bindIface != nil {
+			err2 = unix.BindToDevice(int(fd), bindIface.Name)
+		}
+	})
+	if err1 != nil {
+		return err1
+	} else {
+		return err2
+	}
+}