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Commit 2dc7e48d authored by Jason Baron's avatar Jason Baron Committed by David S. Miller
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Documentation: ip-sysctl.txt: Document tcp_fastopen_key 



Add docs for /proc/sys/net/ipv4/tcp_fastopen_key

Signed-off-by: default avatarJason Baron <jbaron@akamai.com>
Signed-off-by: default avatarChristoph Paasch <cpaasch@apple.com>
Cc: Jeremy Sowden <jeremy@azazel.net>
Acked-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent aa1236cd

Documentation/networking/ip-sysctl.txt

+20 −0
Original line number Diff line number Diff line
@@ -648,6 +648,26 @@ tcp_fastopen_blackhole_timeout_sec - INTEGER 
	0 to disable the blackhole detection.

	By default, it is set to 1hr.



tcp_fastopen_key - list of comma separated 32-digit hexadecimal INTEGERs

	The list consists of a primary key and an optional backup key. The

	primary key is used for both creating and validating cookies, while the

	optional backup key is only used for validating cookies. The purpose of

	the backup key is to maximize TFO validation when keys are rotated.



	A randomly chosen primary key may be configured by the kernel if

	the tcp_fastopen sysctl is set to 0x400 (see above), or if the

	TCP_FASTOPEN setsockopt() optname is set and a key has not been

	previously configured via sysctl. If keys are configured via

	setsockopt() by using the TCP_FASTOPEN_KEY optname, then those

	per-socket keys will be used instead of any keys that are specified via

	sysctl.



	A key is specified as 4 8-digit hexadecimal integers which are separated

	by a '-' as: xxxxxxxx-xxxxxxxx-xxxxxxxx-xxxxxxxx. Leading zeros may be

	omitted. A primary and a backup key may be specified by separating them

	by a comma. If only one key is specified, it becomes the primary key and

	any previously configured backup keys are removed.



tcp_syn_retries - INTEGER

	Number of times initial SYNs for an active TCP connection attempt

	will be retransmitted. Should not be higher than 127. Default value