From: Stefano Brivio <sbrivio@redhat.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: passt-dev@passt.top
Subject: Re: [PATCH v4 00/16] Simplify and correct handling of "spliced" UDP forwarding
Date: Tue, 6 Dec 2022 07:45:38 +0100 [thread overview]
Message-ID: <20221206074538.7124ea93@elisabeth> (raw)
In-Reply-To: <20221130041316.2539575-1-david@gibson.dropbear.id.au>
On Wed, 30 Nov 2022 15:13:00 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:
> The UDP "splicing" (forwarding packets from one L4 socket to another,
> rather than via the tuntap device) code assumes that any given UDP
> port in the init namespace will only communicate with a single port on
> the ns side at a time, and vice versa. This will often be the case,
> but since UDP is a connectionless protocol, it need not be. In fact
> it is not the case in our existing UDP bandwidth checks, although the
> specific configuration there means it's not harmful in that case.
>
> The failure mode in this case can be quite bad: we don't just fall
> back to an unoptimized oath, or drop packets, we will misdirect
> packets to the wrong destination.
>
> This series make some substantial simplifications to how we handle the
> splice forwarding, then corrects it to handle the case of multiple
> source ports sending to a single destination.
Applied (and pushed :)).
--
Stefano
prev parent reply other threads:[~2022-12-06 6:45 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-30 4:13 [PATCH v4 00/16] Simplify and correct handling of "spliced" UDP forwarding David Gibson
2022-11-30 4:13 ` [PATCH v4 01/16] udp: Also bind() connected ports for "splice" forwarding David Gibson
2022-11-30 4:13 ` [PATCH v4 02/16] udp: Separate tracking of inbound and outbound packet flows David Gibson
2022-11-30 4:13 ` [PATCH v4 03/16] udp: Always use sendto() rather than send() for forwarding spliced packets David Gibson
2022-11-30 4:13 ` [PATCH v4 04/16] udp: Don't connect "forward" sockets for spliced flows David Gibson
2022-11-30 4:13 ` [PATCH v4 05/16] udp: Remove the @bound field from union udp_epoll_ref David Gibson
2022-11-30 4:13 ` [PATCH v4 06/16] udp: Split splice field in udp_epoll_ref into (mostly) independent bits David Gibson
2022-11-30 4:13 ` [PATCH v4 07/16] udp: Don't create double sockets for -U port David Gibson
2022-11-30 4:13 ` [PATCH v4 08/16] udp: Re-use fixed bound sockets for packet forwarding when possible David Gibson
2022-11-30 4:13 ` [PATCH v4 09/16] udp: Don't explicitly track originating socket for spliced "connections" David Gibson
2022-11-30 4:13 ` [PATCH v4 10/16] udp: Update UDP "connection" timestamps in both directions David Gibson
2022-11-30 4:13 ` [PATCH v4 11/16] udp: Simplify udp_sock_handler_splice David Gibson
2022-11-30 4:13 ` [PATCH v4 12/16] udp: Make UDP_SPLICE_FRAMES and UDP_TAP_FRAMES_MEM the same thing David Gibson
2022-11-30 4:13 ` [PATCH v4 13/16] udp: Add helper to extract port from a sockaddr_in or sockaddr_in6 David Gibson
2022-11-30 4:13 ` [PATCH v4 14/16] udp: Unify buffers for tap and splice paths David Gibson
2022-11-30 4:13 ` [PATCH v4 15/16] udp: Split send half of udp_sock_handler_splice() from the receive half David Gibson
2022-11-30 4:13 ` [PATCH v4 16/16] udp: Correct splice forwarding when receiving from multiple sources David Gibson
2022-12-06 6:45 ` Stefano Brivio [this message]
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