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From: Jakub Kicinski <kuba@kernel.org>
To: "Toke Høiland-Jørgensen" <toke@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>,
	David Ahern <dsahern@kernel.org>,
	netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH bpf v2 1/3] bpf_redirect_neigh: Support supplying the nexthop as a helper parameter
Date: Tue, 20 Oct 2020 12:01:28 -0700	[thread overview]
Message-ID: <20201020120128.338595e9@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <87v9f422jx.fsf@toke.dk>

On Tue, 20 Oct 2020 20:08:18 +0200 Toke Høiland-Jørgensen wrote:
> > Isn't this backward? The hole could be named in the internal structure.
> > This is a bit of a gray area, but if you name this hole in uAPI and
> > programs start referring to it you will never be able to reuse it.
> > So you may as well not require it to be zeroed..  
> 
> Hmm, yeah, suppose you're right. Doesn't the verifier prevent any part
> of the memory from being unitialised anyway? I seem to recall having run
> into verifier complaints when I didn't initialise struct on the stack...

Good point, in which case we have a convenient way to zero the hole
after nh_family but no convenient way to zero the empty address space
for IPv4 :) (even though that one only needs to be zeroed for the
verifier)

  reply	other threads:[~2020-10-20 19:01 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-20 10:51 [PATCH bpf v2 0/3] bpf: Rework bpf_redirect_neigh() to allow supplying nexthop from caller Toke Høiland-Jørgensen
2020-10-20 10:51 ` [PATCH bpf v2 1/3] bpf_redirect_neigh: Support supplying the nexthop as a helper parameter Toke Høiland-Jørgensen
2020-10-20 15:08   ` Daniel Borkmann
2020-10-20 18:08     ` Toke Høiland-Jørgensen
2020-10-20 16:30   ` Jakub Kicinski
2020-10-20 18:08     ` Toke Høiland-Jørgensen
2020-10-20 19:01       ` Jakub Kicinski [this message]
2020-10-20 19:47         ` Daniel Borkmann
2020-10-20 18:12     ` David Ahern
2020-10-20 18:56       ` Jakub Kicinski
2020-10-20 16:34   ` Jakub Kicinski
2020-10-20 18:03     ` Toke Høiland-Jørgensen
2020-10-20 18:14       ` David Ahern
2020-10-20 18:50         ` Jakub Kicinski
2020-10-20 10:51 ` [PATCH bpf v2 2/3] bpf_fib_lookup: optionally skip neighbour lookup Toke Høiland-Jørgensen
2020-10-20 13:49   ` David Ahern
2020-10-20 15:04     ` Daniel Borkmann
2020-10-20 18:10       ` Toke Høiland-Jørgensen
2020-10-20 10:51 ` [PATCH bpf v2 3/3] selftests: Update test_tc_redirect.sh to use the modified bpf_redirect_neigh() Toke Høiland-Jørgensen

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