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 09:30:03 -0700 [thread overview]
Message-ID: <20201020093003.6e1c7fdb@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <160319106221.15822.2629789706666194966.stgit@toke.dk>
On Tue, 20 Oct 2020 12:51:02 +0200 Toke Høiland-Jørgensen wrote:
> diff --git a/include/linux/filter.h b/include/linux/filter.h
> index 20fc24c9779a..ba9de7188cd0 100644
> --- a/include/linux/filter.h
> +++ b/include/linux/filter.h
> @@ -607,12 +607,21 @@ struct bpf_skb_data_end {
> void *data_end;
> };
>
> +struct bpf_nh_params {
> + u8 nh_family;
> + union {
> + __u32 ipv4_nh;
> + struct in6_addr ipv6_nh;
> + };
> +};
> @@ -4906,6 +4910,18 @@ struct bpf_fib_lookup {
> __u8 dmac[6]; /* ETH_ALEN */
> };
>
> +struct bpf_redir_neigh {
> + /* network family for lookup (AF_INET, AF_INET6) */
> + __u8 nh_family;
> + /* avoid hole in struct - must be set to 0 */
> + __u8 unused[3];
> + /* network address of nexthop; skips fib lookup to find gateway */
> + union {
> + __be32 ipv4_nh;
> + __u32 ipv6_nh[4]; /* in6_addr; network order */
> + };
> +};
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..
next prev parent reply other threads:[~2020-10-20 16:30 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 [this message]
2020-10-20 18:08 ` Toke Høiland-Jørgensen
2020-10-20 19:01 ` Jakub Kicinski
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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