extern void print_data(const unsigned char *, int);
extern void l2tp_print(const u_char *, u_int);
extern void vrrp_print(const u_char *, u_int, int);
extern void print_data(const unsigned char *, int);
extern void l2tp_print(const u_char *, u_int);
extern void vrrp_print(const u_char *, u_int, int);