In all the MPTCP backup related tests, the backup flag was set on one side, and the expected behaviour is to have both sides respecting this decision. That's also the "natural" way, and what the users seem to expect.
On the scheduler side, only the 'backup' field was checked, which is supposed to be set only if the other peer flagged a subflow as backup. But in various places, this flag was also set when the local host flagged the subflow as backup, certainly to have the expected behaviour mentioned above.
Patch 1 modifies the packet scheduler to check if the backup flag has been set on both directions, not to change its behaviour after having applied the following patches. That's what the default packet scheduler should have done since the beginning in v5.7.
Patch 2 fixes the backup flag being mirrored on the MPJ+SYN+ACK by accident since its introduction in v5.7. Instead, the received and sent backup flags are properly distinguished in requests.
Patch 3 stops setting the received backup flag as well when sending an MP_PRIO, something that was done since the MP_PRIO support in v5.12.
Patch 4 adds related and missing MIB counters to be able to easily check if MP_JOIN are sent with a backup flag. Certainly because these counters were not there, the behaviour that is fixed by patches here was not properly verified.
Patch 5 validates the previous patch by extending the MPTCP Join selftest.
Patch 6 fixes the backup support in signal endpoints: if a signal endpoint had the backup flag, it was not set in the MPJ+SYN+ACK as expected. It was only set for ongoing connections, but not future ones as expected, since the introduction of the backup flag in endpoints in v5.10.
Patch 7 validates the previous patch by extending the MPTCP Join selftest as well.
Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- Matthieu Baerts (NGI0) (7): mptcp: sched: check both directions for backup mptcp: distinguish rcv vs sent backup flag in requests mptcp: pm: only set request_bkup flag when sending MP_PRIO mptcp: mib: count MPJ with backup flag selftests: mptcp: join: validate backup in MPJ mptcp: pm: fix backup support in signal endpoints selftests: mptcp: join: check backup support in signal endp
include/trace/events/mptcp.h | 2 +- net/mptcp/mib.c | 2 + net/mptcp/mib.h | 2 + net/mptcp/options.c | 2 +- net/mptcp/pm.c | 12 +++++ net/mptcp/pm_netlink.c | 19 ++++++- net/mptcp/pm_userspace.c | 18 +++++++ net/mptcp/protocol.c | 10 ++-- net/mptcp/protocol.h | 4 ++ net/mptcp/subflow.c | 10 ++++ tools/testing/selftests/net/mptcp/mptcp_join.sh | 72 ++++++++++++++++++++----- 11 files changed, 132 insertions(+), 21 deletions(-) --- base-commit: 301927d2d2eb8e541357ba850bc7a1a74dbbd670 change-id: 20240727-upstream-net-20240727-mptcp-backup-signal-948235f2ad08
Best regards,