After a few years of increasing test coverage in the MPTCP selftests, we realised [1] the last version of the selftests is supposed to run on old kernels without issues.
Supporting older versions is not that easy for this MPTCP case: these selftests are often validating the internals by checking packets that are exchanged, when some MIB counters are incremented after some actions, how connections are getting opened and closed in some cases, etc. In other words, it is not limited to the socket interface between the userspace and the kernelspace. In addition, the current selftests run a lot of different sub-tests but the TAP13 protocol used in the selftests don't support sub-tests: in other words, one failure in sub-tests implies that the whole selftest is seen as failed at the end because sub-tests are not tracked. It is then important to skip sub-tests not supported by old kernels.
To minimise the modifications and reduce the complexity to support old versions, the idea is to look at external signs and skip the whole selftests or just some sub-tests before starting them.
This first part focuses on marking the different selftests as skipped if MPTCP is not even supported. That's what is done in patches 2 to 8. Patch 2/8 introduces a new file (mptcp_lib.sh) to be able to re-use some helpers in the different selftests. The first MPTCP selftest has been introduced in v5.6.
Patch 1/8 is a bit different but still linked: it modifies mptcp_join.sh selftest not to use 'cmp --bytes' which is not supported by the BusyBox implementation. It is apparently quite common to use BusyBox in CI environments. This tool is needed for a subtest introduced in v6.1.
Link: https://lore.kernel.org/stable/CA+G9fYtDGpgT4dckXD-y-N92nqUxuvue_7AtDdBcHrbO... [1] Link: https://github.com/multipath-tcp/mptcp_net-next/issues/368 Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net --- Matthieu Baerts (8): selftests: mptcp: join: avoid using 'cmp --bytes' selftests: mptcp: connect: skip if MPTCP is not supported selftests: mptcp: pm nl: skip if MPTCP is not supported selftests: mptcp: join: skip if MPTCP is not supported selftests: mptcp: diag: skip if MPTCP is not supported selftests: mptcp: simult flows: skip if MPTCP is not supported selftests: mptcp: sockopt: skip if MPTCP is not supported selftests: mptcp: userspace pm: skip if MPTCP is not supported
tools/testing/selftests/net/mptcp/Makefile | 2 +- tools/testing/selftests/net/mptcp/diag.sh | 4 +++ tools/testing/selftests/net/mptcp/mptcp_connect.sh | 4 +++ tools/testing/selftests/net/mptcp/mptcp_join.sh | 17 +++++++-- tools/testing/selftests/net/mptcp/mptcp_lib.sh | 40 ++++++++++++++++++++++ tools/testing/selftests/net/mptcp/mptcp_sockopt.sh | 4 +++ tools/testing/selftests/net/mptcp/pm_netlink.sh | 4 +++ tools/testing/selftests/net/mptcp/simult_flows.sh | 4 +++ tools/testing/selftests/net/mptcp/userspace_pm.sh | 4 +++ 9 files changed, 80 insertions(+), 3 deletions(-) --- base-commit: 9b9e46aa07273ceb96866b2e812b46f1ee0b8d2f change-id: 20230528-upstream-net-20230528-mptcp-selftests-support-old-kernels-part-1-305638f4dbc0
Best regards,