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Message-ID: <c86784f5-ef2c-cfd6-cb75-a67af7e11c3c@iogearbox.net>
Date: Fri, 21 Feb 2020 22:41:14 +0100
From: Daniel Borkmann <daniel@...earbox.net>
To: Jakub Sitnicki <jakub@...udflare.com>, bpf@...r.kernel.org
Cc: netdev@...r.kernel.org, kernel-team@...udflare.com,
John Fastabend <john.fastabend@...il.com>,
Lorenz Bauer <lmb@...udflare.com>, Martin Lau <kafai@...com>
Subject: Re: [PATCH bpf-next v7 00/11] Extend SOCKMAP/SOCKHASH to store
listening sockets
On 2/18/20 6:10 PM, Jakub Sitnicki wrote:
> This patch set turns SOCK{MAP,HASH} into generic collections for TCP
> sockets, both listening and established. Adding support for listening
> sockets enables us to use these BPF map types with reuseport BPF programs.
>
> Why? SOCKMAP and SOCKHASH, in comparison to REUSEPORT_SOCKARRAY, allow the
> socket to be in more than one map at the same time.
>
> Having a BPF map type that can hold listening sockets, and gracefully
> co-exist with reuseport BPF is important if, in the future, we want
> BPF programs that run at socket lookup time [0]. Cover letter for v1 of
> this series tells the full story of how we got here [1].
>
> Although SOCK{MAP,HASH} are not a drop-in replacement for SOCKARRAY just
> yet, because UDP support is lacking, it's a step in this direction. We're
> working with Lorenz on extending SOCK{MAP,HASH} to hold UDP sockets, and
> expect to post RFC series for sockmap + UDP in the near future.
>
> I've dropped Acks from all patches that have been touched since v6.
>
> The audit for missing READ_ONCE annotations for access to sk_prot is
> ongoing. Thus far I've found one location specific to TCP listening sockets
> that needed annotating. This got fixed it in this iteration. I wonder if
> sparse checker could be put to work to identify places where we have
> sk_prot access while not holding sk_lock...
>
> The patch series depends on another one, posted earlier [2], that has been
> split out of it.
>
> Thanks,
> jkbs
>
> [0] https://lore.kernel.org/bpf/20190828072250.29828-1-jakub@cloudflare.com/
> [1] https://lore.kernel.org/bpf/20191123110751.6729-1-jakub@cloudflare.com/
> [2] https://lore.kernel.org/bpf/20200217121530.754315-1-jakub@cloudflare.com/
>
> v6 -> v7:
>
> - Extended the series to cover SOCKHASH. (patches 4-8, 10-11) (John)
>
> - Rebased onto recent bpf-next. Resolved conflicts in recent fixes to
> sk_state checks on sockmap/sockhash update path. (patch 4)
>
> - Added missing READ_ONCE annotation in sock_copy. (patch 1)
>
> - Split out patches that simplify sk_psock_restore_proto [2].
Applied, thanks!
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