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From: John Fastabend <john.fastabend@gmail.com>
To: Cong Wang <xiyou.wangcong@gmail.com>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>,
	duanxiongchun@bytedance.com,
	Dongdong Wang <wangdongdong.6@bytedance.com>,
	jiang.wang@bytedance.com, Cong Wang <cong.wang@bytedance.com>
Subject: Re: [Patch bpf-next 00/19] sock_map: add non-TCP and cross-protocol support
Date: Wed, 03 Feb 2021 12:29:57 -0800	[thread overview]
Message-ID: <601b07c5c8345_4b70c208f2@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <CAM_iQpX-GDysSZTYr-2WsbqFP4VgG5ivcO1vwLvKVHkJ9hjodg@mail.gmail.com>

Cong Wang wrote:
> On Wed, Feb 3, 2021 at 9:48 AM Alexei Starovoitov
> <alexei.starovoitov@gmail.com> wrote:
> >
> > On Tue, Feb 02, 2021 at 08:16:17PM -0800, Cong Wang wrote:
> > > From: Cong Wang <cong.wang@bytedance.com>
> > >
> > > Currently sockmap only fully supports TCP, UDP is partially supported
> > > as it is only allowed to add into sockmap. This patch extends sockmap
> > > with: 1) full UDP support; 2) full AF_UNIX dgram support; 3) cross
> > > protocol support. Our goal is to allow socket splice between AF_UNIX
> > > dgram and UDP.
> >
> > Please expand on the use case. The 'splice between af_unix and udp'
> > doesn't tell me much. The selftest doesn't help to understand the scope either.
> 
> Sure. We have thousands of services connected to a daemon on every host
> with UNIX dgram sockets, after they are moved into VM, we have to add a proxy
> to forward these communications from VM to host, because rewriting thousands
> of them is not practical. This proxy uses a UNIX socket connected to services
> and uses a UDP socket to connect to the host. It is inefficient because data is
> copied between kernel space and user space twice, and we can not use
> splice() which only supports TCP. Therefore, we want to use sockmap to do
> the splicing without even going to user-space at all (after the initial setup).

Thanks for the details. We also have a use-case similar to TCP sockets
to apply policy/redirect to UDP sockets so will want similar semantics to
how TCP skmsg programs work on egress.

> 
> My colleague Jiang (already Cc'ed) is working on the sockmap support for
> vsock so that we can move from UDP to vsock for host-VM communications.

Great. The host-VM channel came up a few times in the initial sockmap work,
but I never got around to starting.

> 
> If this is useful, I can add it in this cover letter in the next update.
> 

Please add to the cover letter. I'll review the series today or
tomorrow, I have a couple things on the TODO list for today that
I need to get done first.

> Thanks.

Thanks for doing this work.

      reply	other threads:[~2021-02-03 20:31 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-03  4:16 [Patch bpf-next 00/19] sock_map: add non-TCP and cross-protocol support Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 01/19] bpf: rename BPF_STREAM_PARSER to BPF_SOCK_MAP Cong Wang
2021-02-05 10:32   ` Jakub Sitnicki
2021-02-09  1:40     ` Cong Wang
2021-02-08  8:21   ` John Fastabend
2021-02-08  9:50     ` Lorenz Bauer
2021-02-09  1:45     ` Cong Wang
2021-02-09  6:48       ` John Fastabend
2021-02-03  4:16 ` [Patch bpf-next 02/19] skmsg: get rid of struct sk_psock_parser Cong Wang
2021-02-05 11:25   ` Jakub Sitnicki
2021-02-08  8:39     ` John Fastabend
2021-02-09  0:19       ` Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 03/19] skmsg: use skb ext instead of TCP_SKB_CB Cong Wang
2021-02-05 22:09   ` Jakub Sitnicki
2021-02-08 18:56     ` Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 04/19] sock_map: rename skb_parser and skb_verdict Cong Wang
2021-02-08  8:27   ` John Fastabend
2021-02-03  4:16 ` [Patch bpf-next 05/19] sock_map: introduce BPF_SK_SKB_VERDICT Cong Wang
2021-02-08  8:31   ` John Fastabend
2021-02-03  4:16 ` [Patch bpf-next 06/19] sock: introduce sk_prot->update_proto() Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 07/19] udp: implement ->sendmsg_locked() Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 08/19] udp: implement ->read_sock() for sockmap Cong Wang
2021-02-08  9:48   ` Lorenz Bauer
2021-02-09  1:35     ` Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 09/19] udp: add ->read_sock() and ->sendmsg_locked() to ipv6 Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 10/19] af_unix: implement ->sendmsg_locked for dgram socket Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 11/19] af_unix: implement ->read_sock() for sockmap Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 12/19] af_unix: implement ->update_proto() Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 13/19] af_unix: set TCP_ESTABLISHED for datagram sockets too Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 14/19] skmsg: extract __tcp_bpf_recvmsg() and tcp_bpf_wait_data() Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 15/19] udp: implement udp_bpf_recvmsg() for sockmap Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 16/19] af_unix: implement unix_dgram_bpf_recvmsg() Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 17/19] sock_map: update sock type checks Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 18/19] selftests/bpf: add test cases for unix and udp sockmap Cong Wang
2021-02-05 10:53   ` Jakub Sitnicki
2021-02-08 18:43     ` Cong Wang
2021-02-03  4:16 ` [Patch bpf-next 19/19] selftests/bpf: add test case for redirection between udp and unix Cong Wang
2021-02-03 17:48 ` [Patch bpf-next 00/19] sock_map: add non-TCP and cross-protocol support Alexei Starovoitov
2021-02-03 19:22   ` Cong Wang
2021-02-03 20:29     ` John Fastabend [this message]

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