DCCP_FEATURE_ACKVECTOR
dccp_remove_feature(cb->pcb, DCCP_OPT_CHANGE_R, DCCP_FEATURE_ACKVECTOR);
dccp_add_feature(cb->pcb, DCCP_OPT_CHANGE_R, DCCP_FEATURE_ACKVECTOR, feature, 1);
case DCCP_FEATURE_ACKVECTOR:
dccp_remove_feature(dp, DCCP_OPT_CONFIRM_L, DCCP_FEATURE_ACKVECTOR);
dccp_add_feature_option(dp, DCCP_OPT_CONFIRM_L, DCCP_FEATURE_ACKVECTOR , val, 1);
dccp_remove_feature(dp, DCCP_OPT_CONFIRM_L, DCCP_FEATURE_ACKVECTOR);