#define SILC_ID_COMPARE_HASH ...

    Compares the nickname hash of the Client ID. Returns TRUE if
    they match. Since the nickname hash is based on the nickname of
    the client this can be used to search the ID by nickname (taking
    the hash out of it) or using the hash from the ID.

    #define SILC_ID_COMPARE_HASH(id1, id2) \
      (!memcmp((id1)->hash, (id2)->hash, CLIENTID_HASH_LEN))