typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
const struct comm_addr *source);
typedef void comm_request_notify_fn(void *commst, void *nst,
typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
const struct comm_addr *source);
typedef void comm_request_notify_fn(void *commst, void *nst,