[IPSEC]: Add xfrm_sysctl.txt.

And use it to document new xfrm_acq_expires sysctl.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/xfrm_sysctl.txt b/Documentation/networking/xfrm_sysctl.txt
new file mode 100644 (file)
index 0000000..5bbd167
--- /dev/null
+++ b/Documentation/networking/xfrm_sysctl.txt
@@ -0,0 +1,4 @@
+/proc/sys/net/core/xfrm_* Variables:
+
+xfrm_acq_expires - INTEGER
+       default 30 - hard timeout in seconds for acquire requests