ipvs: Document sysctl pmtu_disc

Document sysctl pmtu_disc based on commit 3654e61137db ("ipvs: add
pmtu_disc option to disable IP DF for TUN packets").

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

diff --git a/Documentation/networking/ipvs-sysctl.txt b/Documentation/networking/ipvs-sysctl.txt
index a6feecd467cd45f85560cb7e0e1c56f3cccb53fb..056898685d408e463f1a191f36e2384e9974ab6d 100644 (file)
--- a/Documentation/networking/ipvs-sysctl.txt
+++ b/Documentation/networking/ipvs-sysctl.txt
@@ -175,6 +175,14 @@ nat_icmp_send - BOOLEAN
         for VS/NAT when the load balancer receives packets from real
         servers but the connection entries don't exist.
 
+pmtu_disc - BOOLEAN
+       0 - disabled
+       not 0 - enabled (default)
+
+       By default, reject with FRAG_NEEDED all DF packets that exceed
+       the PMTU, irrespective of the forwarding method. For TUN method
+       the flag can be disabled to fragment such packets.
+
 secure_tcp - INTEGER
         0  - disabled (default)