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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Jakub Sitnicki <jakub@cloudflare.com>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
	kernel-team@cloudflare.com, Eric Dumazet <edumazet@google.com>,
	John Fastabend <john.fastabend@gmail.com>,
	Lorenz Bauer <lmb@cloudflare.com>,
	Martin KaFai Lau <kafai@fb.com>
Subject: Re: [PATCH bpf-next v2 00/11] Extend SOCKMAP to store listening sockets
Date: Fri, 10 Jan 2020 16:18:11 -0800	[thread overview]
Message-ID: <20200111001809.uznbax2rr6peexkl@ast-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20200110105027.257877-1-jakub@cloudflare.com>

On Fri, Jan 10, 2020 at 11:50:16AM +0100, Jakub Sitnicki wrote:
> With the realization that properly cloning listening sockets that have
> psock state/callbacks is tricky, comes the second version of patches.
> 
> The spirit of the patch set stays the same - make SOCKMAP a generic
> collection for listening and established sockets. This would let us use the
> SOCKMAP with reuseport today, and in the future hopefully with BPF programs
> that run at socket lookup time [0]. For a bit more context, please see v1
> cover letter [1].
> 
> The biggest change that happened since v1 is how we deal with clearing
> psock state in a copy of parent socket when cloning it (patches 3 & 4).
> 
> As much as I did not want to touch icsk/tcp clone path, it seems
> unavoidable. The changes were kept down to a minimum, with attention to not
> break existing users. That said, a review from the TCP maintainer would be
> invaluable (patches 3 & 4).
> 
> Patches 1 & 2 will conflict with recently posted "Fixes for sockmap/tls
> from more complex BPF progs" series [0]. I'll adapt or split them out this
> series once sockmap/tls fixes from John land in bpf-next branch.
> 
> Some food for thought - is mixing listening and established sockets in the
> same BPF map a good idea? I don't know but I couldn't find a good reason to
> restrict the user.
> 
> Considering how much the code evolved, I didn't carry over Acks from v1.
> 
> Thanks,
> jkbs
> 
> [0] https://lore.kernel.org/bpf/157851776348.1732.12600714815781177085.stgit@ubuntu3-kvm2/T/#t
> [1] https://lore.kernel.org/bpf/20191123110751.6729-1-jakub@cloudflare.com/
> 
> v1 -> v2:
> 
> - af_ops->syn_recv_sock callback is no longer overridden and burdened with
>   restoring sk_prot and clearing sk_user_data in the child socket. As child
>   socket is already hashed when syn_recv_sock returns, it is too late to
>   put it in the right state. Instead patches 3 & 4 restore sk_prot and
>   clear sk_user_data before we hash the child socket. (Pointed out by
>   Martin Lau)
> 
> - Annotate shared access to sk->sk_prot with READ_ONCE/WRITE_ONCE macros as
>   we write to it from sk_msg while socket might be getting cloned on
>   another CPU. (Suggested by John Fastabend)
> 
> - Convert tests for SOCKMAP holding listening sockets to return-on-error
>   style, and hook them up to test_progs. Also use BPF skeleton for setup.
>   Add new tests to cover the race scenario discovered during v1 review.

lgtm
Martin, John, please review.

  parent reply	other threads:[~2020-01-11  0:18 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-10 10:50 [PATCH bpf-next v2 00/11] Extend SOCKMAP to store listening sockets Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 01/11] bpf, sk_msg: Don't reset saved sock proto on restore Jakub Sitnicki
2020-01-11 22:50   ` John Fastabend
2020-01-10 10:50 ` [PATCH bpf-next v2 02/11] net, sk_msg: Annotate lockless access to sk_prot on clone Jakub Sitnicki
2020-01-11 23:14   ` John Fastabend
2020-01-13 15:09     ` Jakub Sitnicki
2020-01-14  3:14       ` John Fastabend
2020-01-20 17:00       ` John Fastabend
2020-01-20 18:11         ` Jakub Sitnicki
2020-01-21 12:42           ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 03/11] net, sk_msg: Clear sk_user_data pointer on clone if tagged Jakub Sitnicki
2020-01-11 23:38   ` John Fastabend
2020-01-12 12:55   ` kbuild test robot
2020-01-13 20:15   ` Martin Lau
2020-01-14 16:04     ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 04/11] tcp_bpf: Don't let child socket inherit parent protocol ops on copy Jakub Sitnicki
2020-01-11  2:42   ` kbuild test robot
2020-01-11  3:02   ` kbuild test robot
2020-01-11 23:48   ` John Fastabend
2020-01-13 22:31     ` Jakub Sitnicki
2020-01-13 22:23   ` Martin Lau
2020-01-13 22:42     ` Jakub Sitnicki
2020-01-13 23:23       ` Martin Lau
2020-01-10 10:50 ` [PATCH bpf-next v2 05/11] bpf, sockmap: Allow inserting listening TCP sockets into sockmap Jakub Sitnicki
2020-01-11 23:59   ` John Fastabend
2020-01-13 15:48     ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 06/11] bpf, sockmap: Don't set up sockmap progs for listening sockets Jakub Sitnicki
2020-01-12  0:51   ` John Fastabend
2020-01-12  1:07     ` John Fastabend
2020-01-13 17:59       ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 07/11] bpf, sockmap: Return socket cookie on lookup from syscall Jakub Sitnicki
2020-01-12  0:56   ` John Fastabend
2020-01-13 23:12   ` Martin Lau
2020-01-14  3:16     ` John Fastabend
2020-01-14 15:48       ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 08/11] bpf, sockmap: Let all kernel-land lookup values in SOCKMAP Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 09/11] bpf: Allow selecting reuseport socket from a SOCKMAP Jakub Sitnicki
2020-01-12  1:00   ` John Fastabend
2020-01-13 23:45   ` Martin Lau
2020-01-15 12:41     ` Jakub Sitnicki
2020-01-13 23:51   ` Martin Lau
2020-01-15 12:57     ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 10/11] selftests/bpf: Extend SK_REUSEPORT tests to cover SOCKMAP Jakub Sitnicki
2020-01-12  1:01   ` John Fastabend
2020-01-10 10:50 ` [PATCH bpf-next v2 11/11] selftests/bpf: Tests for SOCKMAP holding listening sockets Jakub Sitnicki
2020-01-12  1:06   ` John Fastabend
2020-01-13 15:58     ` Jakub Sitnicki
2020-01-11  0:18 ` Alexei Starovoitov [this message]
2020-01-11 22:47 ` [PATCH bpf-next v2 00/11] Extend SOCKMAP to store " John Fastabend

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