ipv4: Documenting two sysctls for tcp PMTU probe

Namely tcp_probe_interval to control how often to restart
a probe. And tcp_probe_threshold to control when stop the
probing in respect to the width of search range in bytes

Signed-off-by: Fan Du <fan.du@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 1b8c964b0d17..4412f695a62f 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -388,6 +388,16 @@ tcp_mtu_probing - INTEGER
           1 - Disabled by default, enabled when an ICMP black hole detected
           2 - Always enabled, use initial MSS of tcp_base_mss.
 
+tcp_probe_interval - INTEGER
+        Controls how often to start TCP Packetization-Layer Path MTU
+        Discovery reprobe. The default is reprobing every 10 minutes as
+        per RFC4821.
+
+tcp_probe_threshold - INTEGER
+        Controls when TCP Packetization-Layer Path MTU Discovery probing
+        will stop in respect to the width of search range in bytes. Default
+        is 8 bytes.
+
 tcp_no_metrics_save - BOOLEAN
         By default, TCP saves various connection metrics in the route cache
         when the connection closes, so that connections established in the