linux-kernel - Re: [RFC PATCH 1/7] net: skbuff: Add tun_vnet

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAF=yD-K0RR5XCuPdHS8gPwppM-HAmodSOVBpS=v+j8X7=Su2Rg@mail.gmail.com>
Date:   Sun, 8 Oct 2023 20:39:07 +0200
From:   Willem de Bruijn <willemdebruijn.kernel@...il.com>
To:     Akihiko Odaki <akihiko.odaki@...nix.com>
Cc:     Jason Wang <jasowang@...hat.com>,
        "Michael S. Tsirkin" <mst@...hat.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        virtualization@...ts.linux-foundation.org,
        linux-kselftest@...r.kernel.org, bpf@...r.kernel.org,
        davem@...emloft.net, kuba@...nel.org, ast@...nel.org,
        daniel@...earbox.net, andrii@...nel.org, kafai@...com,
        songliubraving@...com, yhs@...com, john.fastabend@...il.com,
        kpsingh@...nel.org, rdunlap@...radead.org, willemb@...gle.com,
        gustavoars@...nel.org, herbert@...dor.apana.org.au,
        steffen.klassert@...unet.com, nogikh@...gle.com,
        pablo@...filter.org, decui@...rosoft.com, cai@....pw,
        jakub@...udflare.com, elver@...gle.com, pabeni@...hat.com,
        Yuri Benditovich <yuri.benditovich@...nix.com>
Subject: Re: [RFC PATCH 1/7] net: skbuff: Add tun_vnet_hash flag

On Sun, Oct 8, 2023 at 7:22 AM Akihiko Odaki <akihiko.odaki@...nix.com> wrote:
>
> tun_vnet_hash can use this flag to indicate it stored virtio-net hash
> cache to cb.
>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@...nix.com>
> ---
>  include/linux/skbuff.h | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 4174c4b82d13..e638f157c13c 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -837,6 +837,7 @@ typedef unsigned char *sk_buff_data_t;
>   *     @truesize: Buffer size
>   *     @users: User count - see {datagram,tcp}.c
>   *     @extensions: allocated extensions, valid if active_extensions is nonzero
> + *     @tun_vnet_hash: tun stored virtio-net hash cache to cb
>   */
>
>  struct sk_buff {
> @@ -989,6 +990,7 @@ struct sk_buff {
>  #if IS_ENABLED(CONFIG_IP_SCTP)
>         __u8                    csum_not_inet:1;
>  #endif
> +       __u8                    tun_vnet_hash:1;

sk_buff space is very limited.

No need to extend it, especially for code that stays within a single
subsystem (tun).

To a lesser extent the same point applies to the qdisc_skb_cb.