struct stp *stp_create(const char *name, stp_identifier bridge_id,
void (*send_bpdu)(struct ofpbuf *bpdu, int port_no,
void *aux),
struct stp *stp_create(const char *name, stp_identifier bridge_id,
void (*send_bpdu)(struct ofpbuf *bpdu, int port_no,
void *aux),