netdev - RE: [PATCH bpf-next 5/8] xdp: add xdp_do_redirect_frame() for pre-computed xdp

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

Message-ID: <87wnkdwyov.fsf@toke.dk>
Date:   Thu, 09 Dec 2021 17:05:52 +0100
From:   Toke Høiland-Jørgensen <toke@...hat.com>
To:     John Fastabend <john.fastabend@...il.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Jesper Dangaard Brouer <hawk@...nel.org>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org
Subject: RE: [PATCH bpf-next 5/8] xdp: add xdp_do_redirect_frame() for
 pre-computed xdp_frames

John Fastabend <john.fastabend@...il.com> writes:

> Toke Høiland-Jørgensen wrote:
>> Add an xdp_do_redirect_frame() variant which supports pre-computed
>> xdp_frame structures. This will be used in bpf_prog_run() to avoid having
>> to write to the xdp_frame structure when the XDP program doesn't modify the
>> frame boundaries.
>> 
>> Signed-off-by: Toke Høiland-Jørgensen <toke@...hat.com>
>> ---
>>  include/linux/filter.h |  4 ++++
>>  net/core/filter.c      | 28 +++++++++++++++++++++-------
>>  2 files changed, 25 insertions(+), 7 deletions(-)
>> 
>> diff --git a/include/linux/filter.h b/include/linux/filter.h
>> index b6a216eb217a..845452c83e0f 100644
>> --- a/include/linux/filter.h
>> +++ b/include/linux/filter.h
>> @@ -1022,6 +1022,10 @@ int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,
>>  int xdp_do_redirect(struct net_device *dev,
>>  		    struct xdp_buff *xdp,
>>  		    struct bpf_prog *prog);
>> +int xdp_do_redirect_frame(struct net_device *dev,
>> +			  struct xdp_buff *xdp,
>> +			  struct xdp_frame *xdpf,
>> +			  struct bpf_prog *prog);
>
> I don't really like that we are passing both the xdp_buff ptr and
> xdp_frame *xdpf around when one is always null it looks like?

Yeah, the problem is basically that AF_XDP uses xdp_buff all the way
through, so we can't pass xdp_frame to that. I do agree that it's a bit
ugly, though; maybe we can just do the XSK disambiguation in the caller;
will take another look at this - thanks!

-Toke