Here is a list of all documented struct and union fields with links to the struct/union documentation for each field:

auth_key_len : srtp_crypto_policy_t
auth_tag_len : srtp_crypto_policy_t
auth_type : srtp_crypto_policy_t
cipher_key_len : srtp_crypto_policy_t
cipher_type : srtp_crypto_policy_t
event : srtp_event_data_t
sec_serv : srtp_crypto_policy_t
session : srtp_event_data_t
ssrc : srtp_event_data_t