Revert last change and insure the driver can support other address families.

Pointed out by: ume, matusita

sys/net/if_tun.c

@@ -16,7 +16,10 @@
  * $FreeBSD$
  */
 
+#include "opt_atalk.h"
 #include "opt_inet.h"
+#include "opt_inet6.h"
+#include "opt_ipx.h"
 #include "opt_mac.h"
 
 #include <sys/param.h>
@@ -794,6 +797,21 @@ tunwrite(dev_t dev, struct uio *uio, int flag)
 	case AF_INET:
 		isr = NETISR_IP;
 		break;
+#endif
+#ifdef INET6
+	case AF_INET6:
+		isr = NETISR_IPV6;
+		break;
+#endif
+#ifdef IPX
+	case AF_IPX:
+		isr = NETISR_IPX;
+		break;
+#endif
+#ifdef NETATALK
+	case AF_APPLETALK:
+		isr = NETISR_ATALK2;
+		break;
 #endif
 	default:
 		m_freem(m);