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

From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Joe Stringer <joe@wand.net.nz>
Cc: Martin KaFai Lau <kafai@fb.com>, 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: Thu, 19 Mar 2020 10:36:34 -0700	[thread overview]
Message-ID: <CAEf4BzZWdJf6yWhfJSd8UEgu9i8KrYVaeBhoK-QXcdqzvE_h1Q@mail.gmail.com> (raw)
In-Reply-To: <CAOftzPguUws6sVKg0PQ4pQNhOQL5Q14XiwpHb60=271Jcw+pnA@mail.gmail.com>

On Wed, Mar 18, 2020 at 10:46 PM Joe Stringer <joe@wand.net.nz> wrote:
>
> 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.

Having tests in test_progs makes sure it's executed constantly, both
by maintainers, automated testing and, hopefully, developers. Having
some .sh script has much more coverage in that sense. So if at all
possible, please add new tests to test_progs.