Documentation/networking/mptcp-sysctl.rst
Source file repositories/reference/linux-study-clean/Documentation/networking/mptcp-sysctl.rst
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- Linux kernel
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Documentation/networking/mptcp-sysctl.rst- Extension
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- Domain
- Support Tooling And Documentation
- Bucket
- Documentation
- Inferred role
- Support Tooling And Documentation: documentation
- Status
- atlas-only
Why This File Exists
Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
- Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
Dependency Surface
- No C-style include directives detected by the generator.
Detected Declarations
- No top-level syscall, struct, function, initcall, or export declaration detected by the generator.
Annotated Snippet
.. SPDX-License-Identifier: GPL-2.0
=====================
MPTCP Sysfs variables
=====================
/proc/sys/net/mptcp/* Variables
===============================
add_addr_timeout - INTEGER (seconds)
Set the maximum value of timeout after which an ADD_ADDR control message
will be resent to an MPTCP peer that has not acknowledged a previous
ADD_ADDR message. A dynamically estimated retransmission timeout based
on the estimated connection round-trip-time is used if this value is
lower than the maximum one.
Do not retransmit if set to 0.
The default value matches TCP_RTO_MAX. This is a per-namespace
sysctl.
Default: 120
add_addr_v6_port_drop_ts - BOOLEAN
Control whether preparing an ADD_ADDR with an IPv6 address and a port
should drop the TCP timestamps option to have enough option space to
send the signal.
If there is not enough option space, and the TCP timestamps option
cannot be dropped, the signal cannot be sent. Note that dropping the TCP
timestamps option for one packet of the connection could disrupt some
middleboxes: even if it should be unlikely, they could drop the packet
or block the connection. This is a per-namespace sysctl.
Default: 1 (enabled)
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.
Annotation
- Atlas domain: Support Tooling And Documentation / Documentation.
- Implementation status: atlas-only.
Implementation Notes
- This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
- Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
- Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.