Currently, the MPTCP ADD_ADDR notifications are retransmitted after a fixed timeout controlled by the net.mptcp.add_addr_timeout sysctl knob, if the corresponding "echo" packets are not received before. This can be too slow (or too quick), especially with a too cautious default value set to 2 minutes. - Patch 1: make ADD_ADDR retransmission timeout adaptive, using the TCP's retransmission timeout. The corresponding sysctl knob is now used as a maximum value. - Patch 2: now that these ADD_ADDR retransmissions can happen faster, all MPTCP Join subtests checking ADD_ADDR counters accept more ADD_ADDR than expected (if any). This is aligned with the previous behaviour, when the ADD_ADDR RTO was lowered down to 1 second. - Patch 3: Some CIs have reported that some MPTCP Join signalling tests were unstable. It seems that it is due to the time it can take in slow environments to send a bunch of ADD_ADDR notifications and wait each time for their echo reply. Use a longer transfer to avoid such errors. Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx> --- Notes: - Patch 1 has already been sent before, but the selftests had to be adapted differently, see: https://lore.kernel.org/d5397026-92eb-4a43-9534-954b43ab9305@xxxxxxxxxx --- Geliang Tang (1): mptcp: make ADD_ADDR retransmission timeout adaptive Matthieu Baerts (NGI0) (2): selftests: mptcp: join: tolerate more ADD_ADDR selftests: mptcp: join: allow more time to send ADD_ADDR Documentation/networking/mptcp-sysctl.rst | 8 ++++--- net/mptcp/pm.c | 28 +++++++++++++++++++++---- tools/testing/selftests/net/mptcp/mptcp_join.sh | 25 ++++++++++------------ 3 files changed, 40 insertions(+), 21 deletions(-) --- base-commit: c6142e1913de563ab772f7b0e4ae78d6de9cc5b1 change-id: 20250905-net-next-mptcp-add_addr-retrans-adapt-565b9973acfd Best regards, -- Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
