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  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]
Date:   Thu, 10 Sep 2020 19:50:14 +0200
From:   Jesper Dangaard Brouer <>
To:     Toke Høiland-Jørgensen <>
Cc:     Alexei Starovoitov <>,
        David Ahern <>,
        Hangbin Liu <>, bpf <>,
        Network Development <>,
        Jiri Benc <>,
        Eelco Chaudron <>,
        Alexei Starovoitov <>,
        Daniel Borkmann <>,
        Lorenzo Bianconi <>,
        Andrii Nakryiko <>,
Subject: Re: [PATCHv11 bpf-next 2/5] xdp: add a new helper for dev map
 multicast support

On Thu, 10 Sep 2020 11:44:50 +0200
Toke Høiland-Jørgensen <> wrote:

> Alexei Starovoitov <> writes:
> > On Wed, Sep 9, 2020 at 8:30 PM David Ahern <> wrote:  
> >> >
> >> > I think the packets modification (edit dst mac, add vlan tag, etc) should be
> >> > done on egress, which rely on David's XDP egress support.  
> >>
> >> agreed. The DEVMAP used for redirect can have programs attached that
> >> update the packet headers - assuming you want to update them.  
> >
> > Then you folks have to submit them as one set.
> > As-is the programmer cannot achieve correct behavior.  
> The ability to attach a program to devmaps is already there. See:
> fbee97feed9b ("bpf: Add support to attach bpf program to a devmap entry")
> But now that you mention it, it does appear that this series is skipping
> the hook that will actually run such a program. Didn't realise that was
> in the caller of bq_enqueue() and not inside bq_enqueue() itself...

In the first revisions of Ahern's patchset (before fully integrated in
devmap), this was the case, but it changed in some of the last
revisions. (This also lost the sort-n-bulk effect in the process, that
optimize I-cache).  In these earlier revisions it operated on
xdp_frame's.  It would have been a lot easier for Hangbin's patch if
the devmap-prog operated on these xdp_frame's.

Maybe we should change the devmap-prog approach, and run this on the
xdp_frame's (in bq_xmit_all() to be precise) .  Hangbin's patchset
clearly shows that we need this "layer" between running the xdp_prog and
the devmap-prog. 

Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat

Powered by blists - more mailing lists