binary API message ipsec_spd_dump requires spd_id and optional parameter sa_id. While I can set security associations to max uint32 in order to get all which are related to the SPD, I see no way how to dump all SPDs present on the VPP without knowing the index.

Set the spd_id to max value does not work.

A similar principle works with ip_sec_sa_dump, where sa_id set to max uint32 returns all of them.