diff options
| author | Matthieu Baerts (NGI0) <matttbe@kernel.org> | 2024-09-09 22:09:23 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-09-11 15:57:50 -0700 |
| commit | 27069e7cb3d1cea9377069266acf19b9cc5ad0ae (patch) | |
| tree | b2b59e53ce7fee633efeb019b4903cba0b649ac8 /Documentation | |
| parent | 6982826fe5e53ef115836de7dd397bd970030937 (diff) | |
mptcp: disable active MPTCP in case of blackhole
An MPTCP firewall blackhole can be detected if the following SYN
retransmission after a fallback to "plain" TCP is accepted.
In case of blackhole, a similar technique to the one in place with TFO
is now used: MPTCP can be disabled for a certain period of time, 1h by
default. This time period will grow exponentially when more blackhole
issues get detected right after MPTCP is re-enabled and will reset to
the initial value when the blackhole issue goes away.
The blackhole period can be modified thanks to a new sysctl knob:
blackhole_timeout. Two new MIB counters help understanding what's
happening:
- 'Blackhole', incremented when a blackhole is detected.
- 'MPCapableSYNTXDisabled', incremented when an MPTCP connection
directly falls back to TCP during the blackhole period.
Because the technique is inspired by the one used by TFO, an important
part of the new code is similar to what can find in tcp_fastopen.c, with
some adaptations to the MPTCP case.
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/57
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240909-net-next-mptcp-fallback-x-mpc-v1-3-da7ebb4cd2a3@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/networking/mptcp-sysctl.rst | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/networking/mptcp-sysctl.rst b/Documentation/networking/mptcp-sysctl.rst index fd514bba8c43..95598c21fc8e 100644 --- a/Documentation/networking/mptcp-sysctl.rst +++ b/Documentation/networking/mptcp-sysctl.rst @@ -34,6 +34,17 @@ available_schedulers - STRING Shows the available schedulers choices that are registered. More packet schedulers may be available, but not loaded. +blackhole_timeout - INTEGER (seconds) + Initial time period in second to disable MPTCP on active MPTCP sockets + when a MPTCP firewall blackhole issue happens. This time period will + grow exponentially when more blackhole issues get detected right after + MPTCP is re-enabled and will reset to the initial value when the + blackhole issue goes away. + + 0 to disable the blackhole detection. + + Default: 3600 + checksum_enabled - BOOLEAN Control whether DSS checksum can be enabled. |