[PATCH net 0/5] mptcp: fix stalled connections

[Matthieu Baerts]

Daire reported a few issues with MPTCP where some connections were
stalled in different states. Paolo did a great job fixing them.

Patch 1 fixes bogus receive window shrinkage with multiple subflows. Due
to a race condition and unlucky circumstances, that may lead to
TCP-level window shrinkage, and the connection being stalled on the
sender end.

Patch 2 is a preparation for patch 3 which processes pending subflow
errors on close. Without that and under specific circumstances, the
MPTCP-level socket might not switch to the CLOSE state and stall.

Patch 4 is also a preparation patch for the next one. Patch 5 fixes
MPTCP connections not switching to the CLOSE state when all subflows
have been closed but no DATA_FIN have been exchanged to explicitly close
the MPTCP connection. Now connections in such state will switch to the
CLOSE state after a timeout, still allowing the "make-after-break"
feature but making sure connections don't stall forever. It will be
possible to modify this timeout -- currently matching TCP TIMEWAIT value
(60 seconds) -- in a future version.

Signed-off-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx>
---
Paolo Abeni (5):
      mptcp: fix bogus receive window shrinkage with multiple subflows
      mptcp: move __mptcp_error_report in protocol.c
      mptcp: process pending subflow error on close
      mptcp: rename timer related helper to less confusing names
      mptcp: fix dangling connection hang-up

 net/mptcp/options.c  |   5 +-
 net/mptcp/protocol.c | 165 +++++++++++++++++++++++++++++++--------------------
 net/mptcp/protocol.h |  24 +++++++-
 net/mptcp/subflow.c  |  39 +-----------
 4 files changed, 130 insertions(+), 103 deletions(-)
---
base-commit: 615efed8b63f60ddd69c0b8f32f7783859034fc2
change-id: 20230915-upstream-net-20230915-mptcp-hanging-conn-0609338b1728

Best regards,
-- 
Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx>