TOF_SACK_REDUNDANT
(TOF_SACK | TOF_SACK_REDUNDANT))
(to_flags & (TOF_SACK | TOF_SACK_REDUNDANT)) ==
(to_flags & (TOF_DSACK | TOF_SACK_REDUNDANT)) ==
(TOF_DSACK | TOF_SACK_REDUNDANT)) {
to->to_flags |= TOF_SACK_REDUNDANT;
to->to_flags &= ~TOF_SACK_REDUNDANT;