extern void invert_address(uschar *, uschar *);
extern int ip_bind(int, int, uschar *, int);
extern int ip_connect(int, int, uschar *, int, int);
+extern int ip_get_address_family(int);
extern void ip_keepalive(int, uschar *, BOOL);
extern int ip_recv(int, uschar *, int, int);
extern int ip_socket(int, int);