Messages in this thread | | | Date | Fri, 6 Jan 2023 15:43:39 +0100 | Subject | Re: [PATCH bpf-next v3 00/16] bpfilter | From | Quentin Deslandes <> |
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Le 03/01/2023 à 12:45, Florian Westphal a écrit : > Quentin Deslandes <qde@naccy.de> wrote: >> The patchset is based on the patches from David S. Miller [1], >> Daniel Borkmann [2], and Dmitrii Banshchikov [3]. >> >> Note: I've partially sent this patchset earlier due to a >> mistake on my side, sorry for then noise. >> >> The main goal of the patchset is to prepare bpfilter for >> iptables' configuration blob parsing and code generation. >> >> The patchset introduces data structures and code for matches, >> targets, rules and tables. Beside that the code generation >> is introduced. >> >> The first version of the code generation supports only "inline" >> mode - all chains and their rules emit instructions in linear >> approach. >> >> Things that are not implemented yet: >> 1) The process of switching from the previous BPF programs to the >> new set isn't atomic. > > You can't make this atomic from userspace perspective, the > get/setsockopt API of iptables uses a read-modify-write model.
This refers to updating the programs from bpfilter's side. It won't be atomic from iptables point of view, but currently bpfilter will remove the program associated to a table, before installing the new one. This means packets received in between those operations are not filtered. I assume a better solution is possible.
> Tentatively I'd try to extend libnftnl and generate bpf code there, > since its used by both iptables(-nft) and nftables we'd automatically > get support for both.
That's one of the option, this could also remain in the kernel tree or in a dedicated git repository. I don't know which one would be the best, I'm open to suggestions.
> I was planning to look into "attach bpf progs to raw netfilter hooks" > in Q1 2023, once the initial nf-bpf-codegen is merged.
Is there any plan to support non raw hooks? That's mainly out of curiosity, I don't even know whether that would be a good thing or not.
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