Add a new TUNSIFPID ioctl to update the tun_pid (recorded in

tunopen) with the current pid.

sys/net/if_tun.c

@@ -461,6 +461,9 @@ tunioctl(dev, cmd, data, flag, p)
 			return(EINVAL);
 		}
 		break;
+	case TUNSIFPID:
+		tp->tun_pid = curproc->p_pid;
+		break;
 	case FIONBIO:
 		break;
 	case FIOASYNC:

sys/net/if_tun.h

@@ -41,5 +41,6 @@ struct tuninfo {
 #define	TUNGIFINFO	_IOR('t', 92, struct tuninfo)
 #define	TUNSLMODE	_IOW('t', 93, int)
 #define	TUNSIFMODE	_IOW('t', 94, int)
+#define	TUNSIFPID	_IO('t', 95)
 
 #endif /* !_NET_IF_TUN_H_ */