Add tun inbound for linux

common/tun/tun_linux.go

@@ -0,0 +1,51 @@
+package tun
+
+import (
+	"net/netip"
+
+	"github.com/vishvananda/netlink"
+	"gvisor.dev/gvisor/pkg/tcpip/link/tun"
+)
+
+func Open(name string) (uintptr, error) {
+	tunFd, err := tun.Open(name)
+	if err != nil {
+		return 0, err
+	}
+	return uintptr(tunFd), nil
+}
+
+func Configure(name string, inet4Address netip.Prefix, inet6Address netip.Prefix, mtu uint32) error {
+	tunLink, err := netlink.LinkByName(name)
+	if err != nil {
+		return err
+	}
+
+	if inet4Address.IsValid() {
+		addr4, _ := netlink.ParseAddr(inet4Address.String())
+		err = netlink.AddrAdd(tunLink, addr4)
+		if err != nil {
+			return err
+		}
+	}
+
+	if inet6Address.IsValid() {
+		addr6, _ := netlink.ParseAddr(inet6Address.String())
+		err = netlink.AddrAdd(tunLink, addr6)
+		if err != nil {
+			return err
+		}
+	}
+
+	err = netlink.LinkSetMTU(tunLink, int(mtu))
+	if err != nil {
+		return err
+	}
+
+	err = netlink.LinkSetUp(tunLink)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}