IPFLOW_FLAG_ONLIST
KKASSERT(((ipf)->ipf_flags & IPFLOW_FLAG_ONLIST) == 0); \
(ipf)->ipf_flags |= IPFLOW_FLAG_ONLIST; \
KKASSERT((ipf)->ipf_flags & IPFLOW_FLAG_ONLIST); \
(ipf)->ipf_flags &= ~IPFLOW_FLAG_ONLIST; \
KKASSERT((ipf->ipf_flags & IPFLOW_FLAG_ONLIST) == 0);