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authorJason Baron <jbaron@akamai.com>2019-05-29 12:34:00 -0400
committerDavid S. Miller <davem@davemloft.net>2019-05-30 13:41:26 -0700
commit2dc7e48dee68219dd8921824473306036ea45152 (patch)
tree34caa508f761a70985830a0a8b3716346d0905c4 /Documentation
parentaa1236cdfa898dc4d41cdae8e69d401a2cc7f7f5 (diff)
downloadlinux-2dc7e48dee68219dd8921824473306036ea45152.tar.bz2
Documentation: ip-sysctl.txt: Document tcp_fastopen_key
Add docs for /proc/sys/net/ipv4/tcp_fastopen_key Signed-off-by: Jason Baron <jbaron@akamai.com> Signed-off-by: Christoph Paasch <cpaasch@apple.com> Cc: Jeremy Sowden <jeremy@azazel.net> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/networking/ip-sysctl.txt20
1 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 14fe93049d28..a73b3a02e49a 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -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