netdev - Re: [PATCH 0/2] tools: bpftool: add net (un)load command to load 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: <20190730155915.5bbe3a03@cakuba.netronome.com>
Date:   Tue, 30 Jul 2019 15:59:15 -0700
From:   Jakub Kicinski <jakub.kicinski@...ronome.com>
To:     "Daniel T. Lee" <danieltimlee@...il.com>,
        Stephen Hemminger <stephen@...workplumber.org>,
        David Ahern <dsahern@...il.com>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        John Fastabend <john.fastabend@...il.com>
Cc:     Daniel Borkmann <daniel@...earbox.net>,
        Alexei Starovoitov <ast@...nel.org>, netdev@...r.kernel.org
Subject: Re: [PATCH 0/2] tools: bpftool: add net (un)load command to load
 XDP

On Wed, 31 Jul 2019 03:48:19 +0900, Daniel T. Lee wrote:
> Currently, bpftool net only supports dumping progs loaded on the
> interface. To load XDP prog on interface, user must use other tool
> (eg. iproute2). By this patch, with `bpftool net (un)load`, user can
> (un)load XDP prog on interface.

I don't understand why using another tool is a bad thing :(
What happened to the Unix philosophy?

I remain opposed to duplicating iproute2's functionality under 
bpftool net :( The way to attach bpf programs in the networking
subsystem is through the iproute2 commends - ip and tc.. 

It seems easy enough to add a feature to bpftool but from 
a perspective of someone adding a new feature to the kernel, 
and wanting to update user space components it's quite painful :(

So could you describe to me in more detail why this is a good idea?
Perhaps others can chime in?

>     $ ./bpftool prog
>     ...
>     208: xdp  name xdp_prog1  tag ad822e38b629553f  gpl
>       loaded_at 2019-07-28T18:03:11+0900  uid 0
>     ...
>     $ ./bpftool net load id 208 xdpdrv enp6s0np1
>     $ ./bpftool net
>     xdp:
>     enp6s0np1(5) driver id 208
>     ...
>     $ ./bpftool net unload xdpdrv enp6s0np1
>     $ ./bpftool net
>     xdp:
>     ...
> 
> The word 'load' is used instead of 'attach', since XDP program is not
> considered as 'bpf_attach_type' and can't be attached with
> 'BPF_PROG_ATTACH'. In this context, the meaning of 'load' is, prog will
> be loaded on interface.
> 
> While this patch only contains support for XDP, through `net (un)load`,
> bpftool can further support other prog attach types.
> 
> XDP (un)load tested on Netronome Agilio.