Add docs for /proc/sys/net/ipv4/tcp_fastopen_key
Signed-off-by: Christoph Paasch <cpaa...@apple.com>
Signed-off-by: Jason Baron <jba...@akamai.com>
---
Documentation/networking/ip-sysctl.txt | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/Documentation/networking/ip-sysctl.txt
b/Documentation/networking/ip-sysctl.txt
index 14fe930..e8d848e 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 separted
+ by a '-' as: xxxxxxxx-xxxxxxxx-xxxxxxxx-xxxxxxxx. Leading zeros may be
+ omitted. A primary and a backup key may be specified by separting them
+ by a comma. If only one key is specified, it becomes the primary key and
+ any previous 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
--
2.7.4
