extern void pgm_print(const u_char *, u_int, const u_char *);
extern void cdp_print(const u_char *, u_int, u_int);
extern void stp_print(const u_char *, u_int);
extern void pgm_print(const u_char *, u_int, const u_char *);
extern void cdp_print(const u_char *, u_int, u_int);
extern void stp_print(const u_char *, u_int);