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From: Jakub Sitnicki <jakub@cloudflare.com>
To: John Fastabend <john.fastabend@gmail.com>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
	kernel-team@cloudflare.com, Martin KaFai Lau <kafai@fb.com>
Subject: Re: [PATCH bpf-next 0/8] Extend SOCKMAP to store listening sockets
Date: Mon, 25 Nov 2019 10:22:55 +0100	[thread overview]
Message-ID: <87pnhgnwcw.fsf@cloudflare.com> (raw)
In-Reply-To: <5dda1ed3e7f5d_62c72ad877f985c42f@john-XPS-13-9370.notmuch>

On Sun, Nov 24, 2019 at 07:10 AM CET, John Fastabend wrote:
> Jakub Sitnicki wrote:
>> This patch set makes SOCKMAP more flexible by allowing it to hold TCP
>> sockets that are either in established or listening state. With it SOCKMAP
>> can act as a drop-in replacement for REUSEPORT_SOCKARRAY which reuseport
>> BPF programs use. Granted, it is limited to only TCP sockets.
>>
>> The idea started out at LPC '19 as feedback from John Fastabend to our
>> troubles with repurposing REUSEPORT_SOCKARRAY as a collection of listening
>> sockets accessed by a BPF program ran on socket lookup [1]. Without going
>> into details, REUSEPORT_SOCKARRAY proved to be tightly coupled with
>> reuseport logic. Talk from LPC (see slides [2] or video [3]) highlights
>> what problems we ran into when trying to make REUSEPORT_SOCKARRAY work for
>> our use-case.
>>
>> Patches have evolved quite a bit since the RFC series from a month ago
>> [4]. To recap the RFC feedback, John pointed out that BPF redirect helpers
>> for SOCKMAP need sane semantics when used with listening sockets [5], and
>> that SOCKMAP lookup from BPF would be useful [6]. While Martin asked for
>> UDP support [7].
>
> Curious if you've started looking into UDP support. I had hoped to do
> it but haven't got there yet.

No, not yet. I only made sure the newly added tests were easy to modify
to cover UDP by not hard-coding the socket type.

I expect to break ground with UDP work soon, though. Right after I push
out another iteration of programmable socket lookup [1] patches adapted for
SOCKMAP, which we've been testing internally.

>> As it happens, patches needed more work to get SOCKMAP to actually behave
>> correctly with listening sockets. It turns out flexibility has its
>> price. Change log below outlines them all.
>>
>
> But looks pretty clean to me, only major change here is to add an extra
> hook to remove psock from the child socket. And that looks fine to me and
> cleaner than any other solution I had in mind.
>
> Changes +/- looks good as well most the updates are in selftests to update
> tests and add some new ones. +1

Thanks for taking a look at the patches so quickly. I appreciate it.

-Jakub

[1] https://lore.kernel.org/bpf/20190828072250.29828-1-jakub@cloudflare.com/

      reply	other threads:[~2019-11-25  9:23 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-23 11:07 Jakub Sitnicki
2019-11-23 11:07 ` [PATCH bpf-next 1/8] bpf, sockmap: Return socket cookie on lookup from syscall Jakub Sitnicki
2019-11-24  5:32   ` John Fastabend
2019-11-23 11:07 ` [PATCH bpf-next 2/8] bpf, sockmap: Let all kernel-land lookup values in SOCKMAP Jakub Sitnicki
2019-11-24  5:35   ` John Fastabend
2019-11-23 11:07 ` [PATCH bpf-next 3/8] bpf, sockmap: Allow inserting listening TCP sockets into SOCKMAP Jakub Sitnicki
2019-11-24  5:38   ` John Fastabend
2019-11-23 11:07 ` [PATCH bpf-next 4/8] bpf, sockmap: Don't let child socket inherit psock or its ops on copy Jakub Sitnicki
2019-11-24  5:56   ` John Fastabend
2019-11-25 22:38   ` Martin Lau
2019-11-26 15:54     ` Jakub Sitnicki
2019-11-26 17:16       ` Martin Lau
2019-11-26 18:36         ` Jakub Sitnicki
     [not found]           ` <87sglsfdda.fsf@cloudflare.com>
2019-12-11 17:20             ` Martin Lau
2019-12-12 11:27               ` Jakub Sitnicki
2019-12-12 19:23                 ` Martin Lau
2019-12-17 15:06                   ` Jakub Sitnicki
2019-11-26 18:43         ` John Fastabend
2019-11-27 22:18           ` Jakub Sitnicki
2019-11-23 11:07 ` [PATCH bpf-next 5/8] bpf: Allow selecting reuseport socket from a SOCKMAP Jakub Sitnicki
2019-11-24  5:57   ` John Fastabend
2019-11-25  1:24   ` Alexei Starovoitov
2019-11-25  4:17     ` John Fastabend
2019-11-25 10:40       ` Jakub Sitnicki
2019-11-25 22:07         ` Martin Lau
2019-11-26 14:30           ` Jakub Sitnicki
2019-11-26 19:03             ` Martin Lau
2019-11-27 21:34               ` Jakub Sitnicki
2019-11-23 11:07 ` [PATCH bpf-next 6/8] libbpf: Recognize SK_REUSEPORT programs from section name Jakub Sitnicki
2019-11-24  5:57   ` John Fastabend
2019-11-23 11:07 ` [PATCH bpf-next 7/8] selftests/bpf: Extend SK_REUSEPORT tests to cover SOCKMAP Jakub Sitnicki
2019-11-24  6:00   ` John Fastabend
2019-11-25 22:30   ` Martin Lau
2019-11-26 14:32     ` Jakub Sitnicki
2019-12-12 10:30     ` Jakub Sitnicki
2019-11-23 11:07 ` [PATCH bpf-next 8/8] selftests/bpf: Tests for SOCKMAP holding listening sockets Jakub Sitnicki
2019-11-24  6:04   ` John Fastabend
2019-11-24  6:10 ` [PATCH bpf-next 0/8] Extend SOCKMAP to store " John Fastabend
2019-11-25  9:22   ` Jakub Sitnicki [this message]

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