[PATCH v2 2/2] test: net: add IP defragmentation duplicate-fragment regression test

[Simon Glass]

Hi Mateusz,

On Wed, 17 Jun 2026 at 16:19, Mateusz Furdyna (Nokia)
<mateusz.furdyna at nokia.com> wrote:
>
>
>
> On 14/06/2026 14:16, Simon Glass wrote:
> > Hi Mateusz,
> >
> > On 2026-06-10T14:25:33, Mateusz Furdyna <mateusz.furdyna at nokia.com> wrote:
> >> test: net: add IP defragmentation duplicate-fragment regression test
> >>
> >> Add a unit test for the IP datagram reassembler (CONFIG_IP_DEFRAG) that
> >> covers the duplicate-last-fragment scenario.
> >>
> >> Without the fix the last fragment will re-trigger datagram delivery,
> >> increasing udp_rx_count to 2 and effectively failing the test; with it
> >> applied the test passes with udp_rx_count == 1.
> >>
> >> Signed-off-by: Mateusz Furdyna <mateusz.furdyna at nokia.com>
> >>
> >> test/dm/Makefile     |  1 +
> >>   test/dm/net_defrag.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> >>   2 files changed, 83 insertions(+)
> >
> > Reviewed-by: Simon Glass <sjg at chromium.org>
> >
> >> diff --git a/test/dm/net_defrag.c b/test/dm/net_defrag.c
> >> @@ -0,0 +1,82 @@
> >> +DM_TEST(dm_test_net_ip_defrag_dup_last, 0);
> >
> > Just to check, does this test actually use driver model?
> No, it doesn't. It drives net_process_received_packet() directly,
> nothing is actually using DM in the test path.
>
> I'd followed the existing precedent in test/dm/eth.c
> (dm_test_string_to_ip6(), which similarly doesn't exercise DM), which is
> what prompted my earlier question about whether "ut dm" was the right
> home for this (and stopped me for looking further, my bad).
>
> I'm happy to move it to the lib suite, for instance. Since Jerome has
> already queued this v2 for net/master: should I create v3, a follow-up
> on top of what's queued or just leave it as-is in DM?

Since it works, this is fine. We can always adjust it later if problems come up.

Regards,
Simon