+int ask_permission(const char *, ...) __attribute__((format(printf, 1, 2)));
+int read_keyfile_line(FILE *, const char *, char *, size_t, u_long *);
+
+int tun_open(int, int);
+
+/* Common definitions for ssh tunnel device forwarding */
+#define SSH_TUNMODE_NO 0x00
+#define SSH_TUNMODE_POINTOPOINT 0x01
+#define SSH_TUNMODE_ETHERNET 0x02
+#define SSH_TUNMODE_DEFAULT SSH_TUNMODE_POINTOPOINT
+#define SSH_TUNMODE_YES (SSH_TUNMODE_POINTOPOINT|SSH_TUNMODE_ETHERNET)
+
+#define SSH_TUNID_ANY 0x7fffffff
+#define SSH_TUNID_ERR (SSH_TUNID_ANY - 1)
+#define SSH_TUNID_MAX (SSH_TUNID_ANY - 2)