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From: Jakub Kicinski <kuba@kernel.org>
To: "Maciej Żenczykowski" <zenczykowski@gmail.com>
Cc: "Maciej Żenczykowski" <maze@google.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Linux Network Development Mailing List" <netdev@vger.kernel.org>,
	linux-kernel@vger.kernel.org,
	"David S . Miller" <davem@davemloft.net>
Subject: Re: [PATCH] [RFC] net: bpf: make __bpf_skb_max_len(skb) an skb-independent constant
Date: Tue, 21 Apr 2020 10:27:19 -0700	[thread overview]
Message-ID: <20200421102719.06bdfe02@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <20200420231427.63894-1-zenczykowski@gmail.com>

On Mon, 20 Apr 2020 16:14:27 -0700 Maciej Żenczykowski wrote:
> From: Maciej Żenczykowski <maze@google.com>
> 
> This function is used from:
>   bpf_skb_adjust_room
>   __bpf_skb_change_tail
>   __bpf_skb_change_head
> 
> but in the case of forwarding we're likely calling these functions
> during receive processing on ingress and bpf_redirect()'ing at
> a later point in time to egress on another interface, thus these
> mtu checks are for the wrong device.

Interesting. Without redirecting there should also be no reason
to do this check at ingress, right? So at ingress it's either 
incorrect or unnecessary?

  parent reply	other threads:[~2020-04-21 17:27 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-20 23:14 [PATCH] [RFC] net: bpf: make __bpf_skb_max_len(skb) an skb-independent constant Maciej Żenczykowski
2020-04-20 23:26 ` Maciej Żenczykowski
2020-04-21 17:27 ` Jakub Kicinski [this message]
2020-04-21 20:36   ` Maciej Żenczykowski
2020-04-28 17:53     ` Alexei Starovoitov
2020-05-06 23:32 ` [PATCH v2] net: bpf: permit redirect from L3 to L2 devices at near max mtu Maciej Żenczykowski
2020-05-06 23:55   ` Jakub Kicinski
2020-05-07  0:47     ` Maciej Żenczykowski
2020-05-07  2:32       ` Maciej Żenczykowski
2020-05-07  2:36         ` [PATCH v3] net: bpf: permit redirect from ingress L3 to egress " Maciej Żenczykowski
2020-05-07 15:54           ` Daniel Borkmann
2020-05-07 16:46             ` Maciej Żenczykowski
2020-05-07 21:05               ` Daniel Borkmann

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