Daniel Xu <dxu@xxxxxxxxx> writes: > Support direct writes to nf_conn:mark from TC and XDP prog types. This > is useful when applications want to store per-connection metadata. This > is also particularly useful for applications that run both bpf and > iptables/nftables because the latter can trivially access this > metadata. Looking closer at the nf_conn definition, the mark field (and possibly secmark) seems to be the only field that is likely to be feasible to support direct writes to, as everything else either requires special handling (like status and timeout), or they are composite field that will require helpers anyway to use correctly. Which means we're in the process of creating an API where users have to call helpers to fill in all fields *except* this one field that happens to be directly writable. That seems like a really confusing and inconsistent API, so IMO it strengthens the case for just making a helper for this field as well, even though it adds a bit of overhead (and then solving the overhead issue in a more generic way such as by supporting clever inlining). -Toke
