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2025-03-20mptcp: sysctl: add available_path_managersGeliang Tang
Similarly to net.mptcp.available_schedulers, this patch adds a new one net.mptcp.available_path_managers to list the available path managers. Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250313-net-next-mptcp-pm-ops-intro-v1-11-f4e4a88efc50@kernel.org Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-03-20mptcp: sysctl: set path manager by nameGeliang Tang
Similar to net.mptcp.scheduler, a new net.mptcp.path_manager sysctl knob is added to determine which path manager will be used by each newly created MPTCP socket by setting the name of it. Dealing with an explicit name is easier than with a number, especially when more PMs will be introduced. This sysctl knob makes the old one "pm_type" deprecated. Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250313-net-next-mptcp-pm-ops-intro-v1-8-f4e4a88efc50@kernel.org Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-01-30doc: mptcp: sysctl: blackhole_timeout is per-netnsMatthieu Baerts (NGI0)
All other sysctl entries mention it, and it is a per-namespace sysctl. So mention it as well. Fixes: 27069e7cb3d1 ("mptcp: disable active MPTCP in case of blackhole") Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-01-18mptcp: sysctl: add syn_retrans_before_tcp_fallbackMatthieu Baerts (NGI0)
The number of SYN + MPC retransmissions before falling back to TCP was fixed to 2. This is certainly a good default value, but having a fixed number can be a problem in some environments. The current behaviour means that if all packets are dropped, there will be: - The initial SYN + MPC - 2 retransmissions with MPC - The next ones will be without MPTCP. So typically ~3 seconds before falling back to TCP. In some networks where some temporally blackholes are unfortunately frequent, or when a client tries to initiate connections while the network is not ready yet, this can cause new connections not to have MPTCP connections. In such environments, it is now possible to increase the number of SYN retransmissions with MPTCP options to make sure MPTCP is used. Interesting values are: - 0: the first retransmission will be done without MPTCP options: quite aggressive, but also a higher risk of detecting false-positive MPTCP blackholes. - >= 128: all SYN retransmissions will keep the MPTCP options: back to the < 6.12 behaviour. The default behaviour is not changed here. Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250117-net-next-mptcp-syn_retrans_before_tcp_fallback-v1-1-ab4b187099b0@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-11mptcp: disable active MPTCP in case of blackholeMatthieu Baerts (NGI0)
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>
2024-06-01doc: mptcp: alphabetical orderMatthieu Baerts (NGI0)
Similar to what is done in other 'sysctl' pages: it looks clearer from a readability perspective. This might cause troubles in the short/mid-term with the backports, but by not putting new entries at the end, this can help to reduce conflicts in case of backports in the long term. We don't change the information here too often, so it looks OK to do that. Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://lore.kernel.org/r/20240530-upstream-net-20240520-mptcp-doc-v3-2-e94cdd9f2673@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-06-01doc: mptcp: add missing 'available_schedulers' entryMatthieu Baerts (NGI0)
This sysctl knob has been added recently, but the documentation has not been updated. This knob is used to show the available schedulers choices that are registered, similar to 'net.ipv4.tcp_available_congestion_control'. Fixes: 73c900aa3660 ("mptcp: add net.mptcp.available_schedulers") Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://lore.kernel.org/r/20240530-upstream-net-20240520-mptcp-doc-v3-1-e94cdd9f2673@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-10-25mptcp: add a new sysctl for make after break timeoutPaolo Abeni
The MPTCP protocol allows sockets with no alive subflows to stay in ESTABLISHED status for and user-defined timeout, to allow for later subflows creation. Currently such timeout is constant - TCP_TIMEWAIT_LEN. Let the user-space configure them via a newly added sysctl, to better cope with busy servers and simplify (make them faster) the relevant pktdrill tests. Note that the new know does not apply to orphaned MPTCP socket waiting for the data_fin handshake completion: they always wait TCP_TIMEWAIT_LEN. Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <martineau@kernel.org> Link: https://lore.kernel.org/r/20231023-send-net-next-20231023-2-v1-1-9dc60939d371@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-22mptcp: add a new sysctl schedulerGeliang Tang
This patch adds a new sysctl, named scheduler, to support for selection of different schedulers. Export mptcp_get_scheduler helper to get this sysctl. Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Geliang Tang <geliang.tang@suse.com> Signed-off-by: Mat Martineau <martineau@kernel.org> Link: https://lore.kernel.org/r/20230821-upstream-net-next-20230818-v1-4-0c860fb256a8@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-13Documentation: mptcp: fix pm_type formattingMatthieu Baerts
When looking at the rendered HTML version, we can see 'pm_type' is not displayed with a bold font: https://docs.kernel.org/5.19/networking/mptcp-sysctl.html The empty line under 'pm_type' is then removed to have the same style as the others. Fixes: 6bb63ccc25d4 ("mptcp: Add a per-namespace sysctl to set the default path manager type") Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Link: https://lore.kernel.org/r/20220906180404.1255873-2-matthieu.baerts@tessares.net Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-04-29mptcp: Add a per-namespace sysctl to set the default path manager typeMat Martineau
The new net.mptcp.pm_type sysctl determines which path manager will be used by each newly-created MPTCP socket. v2: Handle builds without CONFIG_SYSCTL v3: Clarify logic for type-specific PM init (Geliang Tang and Paolo Abeni) Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-14mptcp: faster active backup recoveryPaolo Abeni
The msk can use backup subflows to transmit in-sequence data only if there are no other active subflow. On active backup scenario, the MPTCP connection can do forward progress only due to MPTCP retransmissions - rtx can pick backup subflows. This patch introduces a new flag flow MPTCP subflows: if the underlying TCP connection made no progresses for long time, and there are other less problematic subflows available, the given subflow become stale. Stale subflows are not considered active: if all non backup subflows become stale, the MPTCP scheduler can pick backup subflows for plain transmissions. Stale subflows can return in active state, as soon as any reply from the peer is observed. Active backup scenarios can now leverage the available b/w with no restrinction. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/207 Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-22mptcp: add sysctl allow_join_initial_addr_portGeliang Tang
This patch added a new sysctl, named allow_join_initial_addr_port, to control whether allow peers to send join requests to the IP address and port number used by the initial subflow. Suggested-by: Florian Westphal <fw@strlen.de> Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Geliang Tang <geliangtang@gmail.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-18mptcp: add a new sysctl checksum_enabledGeliang Tang
This patch added a new sysctl, named checksum_enabled, to control whether DSS checksum can be enabled. Acked-by: Paolo Abeni <pabeni@redhat.com> Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Geliang Tang <geliangtang@gmail.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-05-28mptcp: restrict values of 'enabled' sysctlMatthieu Baerts
To avoid confusions, it seems better to parse this sysctl parameter as a boolean. We use it as a boolean, no need to parse an integer and bring confusions if we see a value different from 0 and 1, especially with this parameter name: enabled. It seems fine to do this modification because the default value is 1 (enabled). Then the only other interesting value to set is 0 (disabled). All other values would not have changed the default behaviour. Suggested-by: Florian Westphal <fw@strlen.de> Acked-by: Florian Westphal <fw@strlen.de> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-04docs: networking: mptcp: Add MPTCP sysctl entriesMat Martineau
Describe the two MPTCP sysctls, what the values mean, and the default settings. Acked-by: Geliang Tang <geliangtang@gmail.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Jakub Kicinski <kuba@kernel.org>