typedef bool analyze_packet_fn(const struct sk_buff *skb);

// pointer, _t suffix
typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
                         unsigned);

// pointer, _func suffix
typedef int (*get_char_func)(void);

// prototype, _fn suffix
typedef void (elevator_registered_fn)(struct request_queue *);

// prototype, fn suffix
typedef unsigned int nf_hookfn(void *priv,
                               struct sk_buff *skb,
                               const struct nf_hook_state *state);