sctp_authkey
struct sctp_authkey *authkey = NULL;
sockopt_len = sizeof(struct sctp_authkey) + 64 * sizeof(uint8_t);
((struct sctp_authkey *)arg)->sca_assoc_id = id;
struct sctp_authkey *sca;
SCTP_CHECK_AND_CAST(sca, optval, struct sctp_authkey, optsize);
size = optsize - sizeof(struct sctp_authkey);
if (sca->sca_keylength + sizeof(struct sctp_authkey) <= optsize) {