Re: [PATCH bpf-next 5/7] selftests: bpf: add test for sk_assign

From: Joe Stringer <joe@wand.net.nz>
To: Martin KaFai Lau <kafai@fb.com>
Cc: Joe Stringer <joe@wand.net.nz>, bpf <bpf@vger.kernel.org>,
	Lorenz Bauer <lmb@cloudflare.com>,
	netdev <netdev@vger.kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Alexei Starovoitov <ast@kernel.org>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Andrii Nakryiko <andriin@fb.com>
Subject: Re: [PATCH bpf-next 5/7] selftests: bpf: add test for sk_assign
Date: Wed, 18 Mar 2020 22:45:58 -0700	[thread overview]
Message-ID: <CAOftzPguUws6sVKg0PQ4pQNhOQL5Q14XiwpHb60=271Jcw+pnA@mail.gmail.com> (raw)
In-Reply-To: <20200318172735.kxwuvccegquupkwh@kafai-mbp>

On Wed, Mar 18, 2020 at 10:28 AM Martin KaFai Lau <kafai@fb.com> wrote:
>
> On Tue, Mar 17, 2020 at 01:56:12PM -0700, Joe Stringer wrote:
> > On Tue, Mar 17, 2020 at 12:31 AM Martin KaFai Lau <kafai@fb.com> wrote:
> > >
> > > On Thu, Mar 12, 2020 at 04:36:46PM -0700, Joe Stringer wrote:
> > > > From: Lorenz Bauer <lmb@cloudflare.com>
> > > >
> > > > Attach a tc direct-action classifier to lo in a fresh network
> > > > namespace, and rewrite all connection attempts to localhost:4321
> > > > to localhost:1234.
> > > >
> > > > Keep in mind that both client to server and server to client traffic
> > > > passes the classifier.
> > > >
> > > > Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
> > > > Signed-off-by: Joe Stringer <joe@wand.net.nz>
> > > > ---
> > > >  tools/testing/selftests/bpf/.gitignore        |   1 +
> > > >  tools/testing/selftests/bpf/Makefile          |   3 +-
> > > >  .../selftests/bpf/progs/test_sk_assign.c      | 127 +++++++++++++
> > > >  tools/testing/selftests/bpf/test_sk_assign.c  | 176 ++++++++++++++++++
> > > Can this test be put under the test_progs.c framework?
> >
> > I'm not sure, how does the test_progs.c framework handle the logic in
> > "tools/testing/selftests/bpf/test_sk_assign.sh"?
> >
> > Specifically I'm looking for:
> > * Unique netns to avoid messing with host networking stack configuration
> > * Control over routes
> > * Attaching loaded bpf programs to ingress qdisc of a device
> >
> > These are each trivial one-liners in the supplied shell script
> > (admittedly building on existing shell infrastructure in the tests dir
> > and iproute2 package). Seems like maybe the netns parts aren't so bad
> > looking at flow_dissector_reattach.c but anything involving netlink
> > configuration would either require pulling in a netlink library
> > dependency somewhere or shelling out to the existing binaries. At that
> > point I wonder if we're trying to achieve integration of this test
> > into some automated prog runner, is there a simpler way like a place I
> > can just add a one-liner to run the test_sk_assign.sh script?
> I think running a system(cmd) in test_progs is fine, as long as it cleans
> up everything when it is done.  There is some pieces of netlink
> in tools/lib/bpf/netlink.c that may be reuseable also.
>
> Other than test_progs.c, I am not aware there is a script to run
> all *.sh.  I usually only run test_progs.
>
> Cc: Andrii who has fixed many selftest issues recently.

OK, unless I get some other guidance I'll take a stab at this.