dccp_add_feature_option
int dccp_add_feature_option(struct dccpcb *, u_int8_t, u_int8_t, char *, u_int8_t);
return dccp_add_feature_option(dp, opt, 0, val, val_len);
dccp_add_feature_option(dp, DCCP_OPT_CONFIRM_L, DCCP_FEATURE_CC , val, 1);
dccp_add_feature_option(dp, DCCP_OPT_CONFIRM_L, DCCP_FEATURE_ACKVECTOR , val, 1);