When looking at improving the user experience around the MPTCP endpoints
setup, I noticed that setting an endpoint with both the 'signal' and the
'subflow' flags -- as it has been done in the past by users according to
bug reports we got -- were resulting on only announcing the endpoint,
but not using it to create subflows: the 'subflow' flag was then
ignored.
My initial thought was to modify IPRoute2 to warn the user when the two
flags were set, but it doesn't sound normal to ignore one of them. I
then looked at modifying the kernel not to allow having the two flags
set, but when discussing about that with Mat, we thought it was maybe
not ideal to do that, as there might be use-cases, we might break some
configs, and it was working before apparently. So instead, I fixed the
support on the kernel side (patch 5) using Paolo's suggestion. This also
includes a fix on the options side (patch 1), an explicit deny of some
options combinations (patch 2), and some refactoring (patches 3 and 4).
While at it, I added a new selftest (patch 7) to validate this case --
including a modification of the chk_add_nr helper to inverse the sides
were the counters are checked (patch 6) -- and allowed ADD_ADDR echo
just after the MP_JOIN 3WHS.
While working on that, I also noticed that re-using IDs were not
possible in some cases -- see patches 8, 10 and 12 -- and the accounting
was not correct in some other cases -- see patches 14 to 17.
The selftests modification have the same Fixes tag as the previous
commit, but they should not get the 'Cc: Stable' one later: if the
backport can work, that's not, if not, no need to worry, many CIs will
use the selftests from the last stable version to validate previous
stable releases.
The last patches don't have any modifications of the selftests attached
to them, because the current ones were producing the new WARN() that
have just been added.
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Changes in v3:
- Small changes in patches 10 and 14, see individual changelog (Geliang)
- New patches 18-20: small fixes
- Link to v2: https://lore.kernel.org/r/20240715-mptcp-pm-avail-v2-0-fc5153bd1f6e@kernel.org
Changes in v2:
- Do not split id_avail_bitmap per target in patch 5 (Paolo)
- Explicit deny (patch 2), reduce indentation (patch 3), stop earlier
(patch 4) (Paolo)
- New fixes and tests (patches 8-17).
- Link to v1: https://lore.kernel.org/r/20240621-mptcp-pm-avail-v1-0-b692d5eb89b5@kernel.org
---
Matthieu Baerts (NGI0) (20):
mptcp: fully established after ADD_ADDR echo on MPJ
mptcp: pm: deny endp with signal + subflow + port
mptcp: pm: reduce indentation blocks
mptcp: pm: don't try to create sf if alloc failed
mptcp: pm: do not ignore 'subflow' if 'signal' flag is also set
selftests: mptcp: join: ability to invert ADD_ADDR check
selftests: mptcp: join: test both signal & subflow
mptcp: pm: re-using ID of unused removed ADD_ADDR
selftests: mptcp: join: check re-using ID of unused ADD_ADDR
mptcp: pm: re-using ID of unused removed subflows
selftests: mptcp: join: check re-using ID of closed subflow
mptcp: pm: re-using ID of unused flushed subflows
selftests: mptcp: join: test for flush/re-add endpoints
mptcp: pm: remove mptcp_pm_remove_subflow()
mptcp: pm: only mark 'subflow' endp as available
mptcp: pm: only decrement add_addr_accepted for MPJ req
mptcp: pm: check add_addr_accept_max before accepting new ADD_ADDR
mptcp: pm: only in-kernel cannot have entries with ID 0
mptcp: pm: fullmesh: select the right ID later
selftests: mptcp: join: validate fullmesh endp on 1st sf
net/mptcp/options.c | 3 +-
net/mptcp/pm.c | 13 ---
net/mptcp/pm_netlink.c | 136 +++++++++++++++++-------
net/mptcp/protocol.h | 3 -
tools/testing/selftests/net/mptcp/mptcp_join.sh | 131 ++++++++++++++++++-----
5 files changed, 205 insertions(+), 81 deletions(-)
---
base-commit: 296fa2eabd1b78e41a4ff9e4d345be994de96ea8
change-id: 20240620-mptcp-pm-avail-f5e3957be441
Best regards,
--
Matthieu Baerts (NGI0) <matttbe@kernel.org>