From: Jesper Dangaard Brouer <brouer@redhat.com>
To: David Ahern <dsahern@gmail.com>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
Daniel Borkmann <borkmann@iogearbox.net>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
maze@google.com, lmb@cloudflare.com, shaun@tigera.io,
Lorenzo Bianconi <lorenzo@kernel.org>,
marek@cloudflare.com, John Fastabend <john.fastabend@gmail.com>,
Jakub Kicinski <kuba@kernel.org>,
eyal.birger@gmail.com, brouer@redhat.com
Subject: Re: [PATCH bpf-next V4 2/5] bpf: bpf_fib_lookup return MTU value as output when looked up
Date: Fri, 30 Oct 2020 18:01:02 +0100 [thread overview]
Message-ID: <20201030180102.567d3751@carbon> (raw)
In-Reply-To: <b41f461b-ec5b-edb0-d69d-b413e93359de@gmail.com>
On Tue, 27 Oct 2020 11:15:31 -0600
David Ahern <dsahern@gmail.com> wrote:
> On 10/27/20 10:26 AM, Jesper Dangaard Brouer wrote:
> > The BPF-helpers for FIB lookup (bpf_xdp_fib_lookup and bpf_skb_fib_lookup)
> > can perform MTU check and return BPF_FIB_LKUP_RET_FRAG_NEEDED. The BPF-prog
> > don't know the MTU value that caused this rejection.
> >
> > If the BPF-prog wants to implement PMTU (Path MTU Discovery) (rfc1191) it
> > need to know this MTU value for the ICMP packet.
> >
> > Patch change lookup and result struct bpf_fib_lookup, to contain this MTU
> > value as output via a union with 'tot_len' as this is the value used for
> > the MTU lookup.
> >
> > Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> > ---
> > include/uapi/linux/bpf.h | 11 +++++++++--
> > net/core/filter.c | 17 ++++++++++++-----
> > tools/include/uapi/linux/bpf.h | 11 +++++++++--
> > 3 files changed, 30 insertions(+), 9 deletions(-)
>
> Reviewed-by: David Ahern <dsahern@kernel.org>
Thanks a lot for the review. I didn't propagate-it-over in V5 of this
patch, as I changed the name of the output member from mtu to
mtu_result in V5. Please review V5 and give your review consent.
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2020-10-30 17:01 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 16:26 [PATCH bpf-next V4 0/5] bpf: New approach for BPF MTU handling Jesper Dangaard Brouer
2020-10-27 16:26 ` [PATCH bpf-next V4 1/5] bpf: Remove MTU check in __bpf_skb_max_len Jesper Dangaard Brouer
2020-10-30 19:24 ` John Fastabend
2020-10-27 16:26 ` [PATCH bpf-next V4 2/5] bpf: bpf_fib_lookup return MTU value as output when looked up Jesper Dangaard Brouer
2020-10-27 17:15 ` David Ahern
2020-10-30 17:01 ` Jesper Dangaard Brouer [this message]
2020-10-28 12:49 ` Dan Carpenter
2020-10-30 14:35 ` Jesper Dangaard Brouer
2020-10-27 16:27 ` [PATCH bpf-next V4 3/5] bpf: add BPF-helper for MTU checking Jesper Dangaard Brouer
2020-10-27 16:27 ` [PATCH bpf-next V4 4/5] bpf: drop MTU check when doing TC-BPF redirect to ingress Jesper Dangaard Brouer
2020-10-27 16:27 ` [PATCH bpf-next V4 5/5] bpf: make it possible to identify BPF redirected SKBs Jesper Dangaard Brouer
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