From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Daniel Borkmann <daniel@iogearbox.net>,
David Ahern <dsahern@gmail.com>, David Ahern <dsahern@kernel.org>,
netdev@vger.kernel.org
Cc: davem@davemloft.net, kuba@kernel.org,
prashantbhole.linux@gmail.com, brouer@redhat.com,
john.fastabend@gmail.com, ast@kernel.org, kafai@fb.com,
songliubraving@fb.com, yhs@fb.com, andriin@fb.com,
David Ahern <dahern@digitalocean.com>
Subject: Re: [PATCH v5 bpf-next 00/11] net: Add support for XDP in egress path
Date: Tue, 19 May 2020 16:52:42 +0200 [thread overview]
Message-ID: <87lflom0xx.fsf@toke.dk> (raw)
In-Reply-To: <d705cf50-b5b3-8778-16fe-3a29b9eb1e85@iogearbox.net>
Daniel Borkmann <daniel@iogearbox.net> writes:
> On 5/19/20 2:02 AM, David Ahern wrote:
>> On 5/18/20 3:06 PM, Daniel Borkmann wrote:
>>> So given we neither call this hook on the skb path, nor XDP_TX nor
>>> AF_XDP's TX
>>> path, I was wondering also wrt the discussion with John if it makes
>>> sense to
>>> make this hook a property of the devmap _itself_, for example, to have a
>>> default
>>> BPF prog upon devmap creation or a dev-specific override that is passed
>>> on map
>>> update along with the dev. At least this would make it very clear where
>>> this is
>>> logically tied to and triggered from, and if needed (?) would provide
>>> potentially
>>> more flexibility on specifiying BPF progs to be called while also
>>> solving your
>>> use-case.
>>
>> You lost me on the 'property of the devmap.' The programs need to be per
>> netdevice, and devmap is an array of devices. Can you elaborate?
>
> I meant that the dev{map,hash} would get extended in a way where the
> __dev_map_update_elem() receives an (ifindex, BPF prog fd) tuple from
> user space and holds the program's ref as long as it is in the map slot.
> Then, upon redirect to the given device in the devmap, we'd execute the
> prog as well in order to also allow for XDP_DROP policy in there. Upon
> map update when we drop the dev from the map slot, we also release the
> reference to the associated BPF prog. What I mean to say wrt 'property
> of the devmap' is that this program is _only_ used in combination with
> redirection to devmap, so given we are not solving all the other egress
> cases for reasons mentioned, it would make sense to tie it logically to
> the devmap which would also make it clear from a user perspective _when_
> the prog is expected to run.
I would be totally on board with this. Also makes sense for the
multicast map type, if you want to fix up the packet after the redirect,
just stick the fixer-upper program into the map along with the ifindex.
-Toke
next prev parent reply other threads:[~2020-05-19 14:53 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 1:45 [PATCH v5 bpf-next 00/11] net: Add support for XDP in egress path David Ahern
2020-05-13 1:45 ` [PATCH v5 bpf-next 01/11] net: Refactor convert_to_xdp_frame David Ahern
2020-05-13 1:45 ` [PATCH v5 bpf-next 02/11] net: uapi for XDP programs in the egress path David Ahern
2020-05-13 1:45 ` [PATCH v5 bpf-next 03/11] net: Add XDP setup and query commands for Tx programs David Ahern
2020-05-13 1:46 ` [PATCH v5 bpf-next 04/11] net: Add BPF_XDP_EGRESS as a bpf_attach_type David Ahern
2020-05-13 1:46 ` [PATCH v5 bpf-next 05/11] xdp: Add xdp_txq_info to xdp_buff David Ahern
2020-05-13 1:46 ` [PATCH v5 bpf-next 06/11] net: set XDP egress program on netdevice David Ahern
2020-05-13 1:46 ` [PATCH v5 bpf-next 07/11] net: Support xdp in the Tx path for xdp_frames David Ahern
2020-05-13 1:46 ` [PATCH v5 bpf-next 08/11] libbpf: Add egress XDP support David Ahern
2020-05-13 1:46 ` [PATCH v5 bpf-next 09/11] bpftool: Add support for XDP egress David Ahern
2020-05-13 1:46 ` [PATCH v5 bpf-next 10/11] selftest: Add xdp_egress attach tests David Ahern
2020-05-13 1:46 ` [PATCH v5 bpf-next 11/11] samples/bpf: add XDP egress support to xdp1 David Ahern
2020-05-13 10:43 ` [PATCH v5 bpf-next 00/11] net: Add support for XDP in egress path Toke Høiland-Jørgensen
2020-05-13 19:37 ` David Ahern
2020-05-15 22:54 ` John Fastabend
2020-05-15 23:15 ` David Ahern
2020-05-18 18:10 ` John Fastabend
2020-05-18 23:52 ` David Ahern
2020-05-19 6:04 ` John Fastabend
2020-05-18 3:40 ` David Ahern
2020-05-18 9:08 ` Toke Høiland-Jørgensen
2020-05-18 14:44 ` David Ahern
2020-05-18 18:00 ` Toke Høiland-Jørgensen
2020-05-18 21:06 ` Daniel Borkmann
2020-05-19 0:02 ` David Ahern
2020-05-19 13:31 ` Daniel Borkmann
2020-05-19 14:21 ` Jesper Dangaard Brouer
2020-05-19 16:58 ` Lorenzo Bianconi
2020-05-19 14:52 ` Toke Høiland-Jørgensen [this message]
2020-05-19 16:37 ` David Ahern
2020-05-18 23:37 ` David Ahern
2020-05-18 21:23 ` Daniel Borkmann
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