sctp_sack_info
((struct sctp_sack_info *)arg)->sack_assoc_id = id;
struct sctp_sack_info *sack;
SCTP_CHECK_AND_CAST(sack, optval, struct sctp_sack_info, *optsize);
*optsize = sizeof(struct sctp_sack_info);
struct sctp_sack_info *sack;
SCTP_CHECK_AND_CAST(sack, optval, struct sctp_sack_info, optsize);