so_upcall_t
soupcall_set(struct socket *so, sb_which which, so_upcall_t func, void *arg)
solisten_upcall_set(struct socket *so, so_upcall_t func, void *arg)
so_upcall_t *sol_upcall; /* (e) */
void soupcall_set(struct socket *, sb_which, so_upcall_t, void *);
void solisten_upcall_set(struct socket *, so_upcall_t, void *);