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diff --git a/Documentation/networking/mptcp-sysctl.rst b/Documentation/networking/mptcp-sysctl.rst new file mode 100644 index 000000000000..1683c139821e --- /dev/null +++ b/Documentation/networking/mptcp-sysctl.rst @@ -0,0 +1,151 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +MPTCP Sysfs variables +===================== + +/proc/sys/net/mptcp/* Variables +=============================== + +add_addr_timeout - INTEGER (seconds) + Set the timeout after which an ADD_ADDR control message will be + resent to an MPTCP peer that has not acknowledged a previous + ADD_ADDR message. + + Do not retransmit if set to 0. + + The default value matches TCP_RTO_MAX. This is a per-namespace + sysctl. + + Default: 120 + +allow_join_initial_addr_port - BOOLEAN + Allow peers to send join requests to the IP address and port number used + by the initial subflow if the value is 1. This controls a flag that is + sent to the peer at connection time, and whether such join requests are + accepted or denied. + + Joins to addresses advertised with ADD_ADDR are not affected by this + value. + + This is a per-namespace sysctl. + + Default: 1 + +available_path_managers - STRING + Shows the available path managers choices that are registered. More + path managers may be available, but not loaded. + +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. This is a per-namespace sysctl. + + Default: 3600 + +checksum_enabled - BOOLEAN + Control whether DSS checksum can be enabled. + + DSS checksum can be enabled if the value is nonzero. This is a + per-namespace sysctl. + + Default: 0 + +close_timeout - INTEGER (seconds) + Set the make-after-break timeout: in absence of any close or + shutdown syscall, MPTCP sockets will maintain the status + unchanged for such time, after the last subflow removal, before + moving to TCP_CLOSE. + + The default value matches TCP_TIMEWAIT_LEN. This is a per-namespace + sysctl. + + Default: 60 + +enabled - BOOLEAN + Control whether MPTCP sockets can be created. + + MPTCP sockets can be created if the value is 1. This is a + per-namespace sysctl. + + Default: 1 (enabled) + +path_manager - STRING + Set the default path manager name to use for each new MPTCP + socket. In-kernel path management will control subflow + connections and address advertisements according to + per-namespace values configured over the MPTCP netlink + API. Userspace path management puts per-MPTCP-connection subflow + connection decisions and address advertisements under control of + a privileged userspace program, at the cost of more netlink + traffic to propagate all of the related events and commands. + + This is a per-namespace sysctl. + + * "kernel" - In-kernel path manager + * "userspace" - Userspace path manager + + Default: "kernel" + +pm_type - INTEGER + Set the default path manager type to use for each new MPTCP + socket. In-kernel path management will control subflow + connections and address advertisements according to + per-namespace values configured over the MPTCP netlink + API. Userspace path management puts per-MPTCP-connection subflow + connection decisions and address advertisements under control of + a privileged userspace program, at the cost of more netlink + traffic to propagate all of the related events and commands. + + This is a per-namespace sysctl. + + Deprecated since v6.15, use path_manager instead. + + * 0 - In-kernel path manager + * 1 - Userspace path manager + + Default: 0 + +scheduler - STRING + Select the scheduler of your choice. + + Support for selection of different schedulers. This is a per-namespace + sysctl. + + Default: "default" + +stale_loss_cnt - INTEGER + The number of MPTCP-level retransmission intervals with no traffic and + pending outstanding data on a given subflow required to declare it stale. + The packet scheduler ignores stale subflows. + A low stale_loss_cnt value allows for fast active-backup switch-over, + an high value maximize links utilization on edge scenarios e.g. lossy + link with high BER or peer pausing the data processing. + + This is a per-namespace sysctl. + + Default: 4 + +syn_retrans_before_tcp_fallback - INTEGER + The number of SYN + MP_CAPABLE retransmissions before falling back to + TCP, i.e. dropping the MPTCP options. In other words, if all the packets + are dropped on the way, there will be: + + * The initial SYN with MPTCP support + * This number of SYN retransmitted with MPTCP support + * The next SYN retransmissions will be without MPTCP support + + 0 means the first retransmission will be done without MPTCP options. + >= 128 means that all SYN retransmissions will keep the MPTCP options. A + lower number might increase false-positive MPTCP blackholes detections. + This is a per-namespace sysctl. + + Default: 2 |