switch core support

add nekobox_core

linux: use sing-box for vpn

go/pkg/protect_server/protect_server_linux.go

@@ -0,0 +1,95 @@
+package protect_server
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"os/signal"
+	"reflect"
+	"syscall"
+)
+
+func getOneFd(socket int) (int, error) {
+	// recvmsg
+	buf := make([]byte, syscall.CmsgSpace(4))
+	_, _, _, _, err := syscall.Recvmsg(socket, nil, buf, 0)
+	if err != nil {
+		return 0, err
+	}
+
+	// parse control msgs
+	var msgs []syscall.SocketControlMessage
+	msgs, err = syscall.ParseSocketControlMessage(buf)
+
+	if len(msgs) != 1 {
+		return 0, fmt.Errorf("invaild msgs count: %d", len(msgs))
+	}
+
+	var fds []int
+	fds, err = syscall.ParseUnixRights(&msgs[0])
+	if len(fds) != 1 {
+		return 0, fmt.Errorf("invaild fds count: %d", len(fds))
+	}
+	return fds[0], nil
+}
+
+// GetFdFromConn get net.Conn's file descriptor.
+func GetFdFromConn(l net.Conn) int {
+	v := reflect.ValueOf(l)
+	netFD := reflect.Indirect(reflect.Indirect(v).FieldByName("fd"))
+	pfd := reflect.Indirect(netFD.FieldByName("pfd"))
+	fd := int(pfd.FieldByName("Sysfd").Int())
+	return fd
+}
+
+func ServeProtect(path string, fwmark int) {
+	fmt.Println("ServeProtect", path, fwmark)
+
+	os.Remove(path)
+	defer os.Remove(path)
+
+	l, err := net.ListenUnix("unix", &net.UnixAddr{Name: path, Net: "unix"})
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer l.Close()
+
+	os.Chmod(path, 0777)
+
+	go func() {
+		for {
+			c, err := l.Accept()
+			if err != nil {
+				log.Println("Accept:", err)
+				return
+			}
+
+			go func() {
+				socket := GetFdFromConn(c)
+				defer c.Close()
+
+				fd, err := getOneFd(socket)
+				if err != nil {
+					log.Println("getOneFd:", err)
+					return
+				}
+				defer syscall.Close(fd)
+
+				if err := syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_MARK, fwmark); err != nil {
+					log.Println("syscall.SetsockoptInt:", err)
+				}
+
+				if err == nil {
+					c.Write([]byte{1})
+				} else {
+					c.Write([]byte{0})
+				}
+			}()
+		}
+	}()
+
+	sigCh := make(chan os.Signal, 1)
+	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+	<-sigCh
+}