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From: David Ahern <dsahern@gmail.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>, bpf@vger.kernel.org
Cc: 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
Subject: Re: [PATCH bpf-next V3 2/6] bpf: bpf_fib_lookup return MTU value as output when looked up
Date: Thu, 8 Oct 2020 21:05:44 -0700	[thread overview]
Message-ID: <d06ee8a0-79f1-d9c7-ba16-e25f97736c0a@gmail.com> (raw)
In-Reply-To: <160216614748.882446.6805410687451779968.stgit@firesoul>

On 10/8/20 7:09 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@gmail.com>


  reply	other threads:[~2020-10-09  4:05 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-08 14:08 [PATCH bpf-next V3 0/6] bpf: New approach for BPF MTU handling Jesper Dangaard Brouer
2020-10-08 14:09 ` [PATCH bpf-next V3 1/6] bpf: Remove MTU check in __bpf_skb_max_len Jesper Dangaard Brouer
2020-10-09 16:12   ` Daniel Borkmann
2020-10-09 18:26     ` Maciej Żenczykowski
2020-10-10 10:25     ` Jesper Dangaard Brouer
2020-10-08 14:09 ` [PATCH bpf-next V3 2/6] bpf: bpf_fib_lookup return MTU value as output when looked up Jesper Dangaard Brouer
2020-10-09  4:05   ` David Ahern [this message]
2020-10-08 14:09 ` [PATCH bpf-next V3 3/6] bpf: add BPF-helper for MTU checking Jesper Dangaard Brouer
2020-10-09 23:29   ` Maciej Żenczykowski
2020-10-21 11:32     ` Jesper Dangaard Brouer
2020-10-12 15:54   ` Lorenz Bauer
2020-10-08 14:09 ` [PATCH bpf-next V3 4/6] bpf: make it possible to identify BPF redirected SKBs Jesper Dangaard Brouer
2020-10-09 16:47   ` Daniel Borkmann
2020-10-09 18:33     ` Maciej Żenczykowski
2020-10-10 11:09       ` Jesper Dangaard Brouer
2020-10-12 21:04         ` Maciej Żenczykowski
2020-10-08 14:09 ` [PATCH bpf-next V3 5/6] bpf: drop MTU check when doing TC-BPF redirect to ingress Jesper Dangaard Brouer
2020-10-09 23:17   ` Maciej Żenczykowski
2020-10-08 14:09 ` [PATCH bpf-next V3 6/6] net: inline and splitup is_skb_forwardable Jesper Dangaard Brouer
2020-10-09 16:33 ` [PATCH bpf-next V3 0/6] bpf: New approach for BPF MTU handling Jakub Kicinski
2020-10-09 20:49   ` John Fastabend
2020-10-09 21:07     ` Alexei Starovoitov
2020-10-09 21:57       ` Maciej Żenczykowski
2020-10-09 23:00     ` Jakub Kicinski
2020-10-10 10:44       ` Jesper Dangaard Brouer
2020-10-10 16:32         ` Jakub Kicinski
2020-10-10 23:52           ` John Fastabend
2020-10-11 23:30             ` Jakub Kicinski
2020-10-13 20:40           ` Jesper Dangaard Brouer
2020-10-13 23:07             ` Jakub Kicinski
2020-10-13 23:37               ` Alexei Starovoitov
2020-10-13 23:54                 ` Maciej Żenczykowski

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