IGMP: Document igmp_link_local_mcast_reports

Document the addition of a new sysctl variable which controls the
generation of IGMP reports for link local multicast groups in the
224.0.0.X range.

IGMP reports for local multicast groups can now be optionally
inhibited by setting the value to zero e.g.:
echo 0 > /proc/sys/net/ipv4/igmp_link_local_mcast_reports

To retain backwards compatibility the previous behaviour is retained
by default on system boot or reverted by setting the value back to
non-zero.

Signed-off-by: Philip Downey <pdowney@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index ac77a13d2ea2cc2417e45780904c06dc0d6e3bcc..ebe94f2cab9811e62f0ea1d64c0d6c75838d0367 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1201,6 +1201,11 @@ xfrm4_gc_thresh - INTEGER
        destination cache entries.  At twice this value the system will
        refuse new allocations.
 
+igmp_link_local_mcast_reports - BOOLEAN
+       Enable IGMP reports for link local multicast groups in the
+       224.0.0.X range.
+       Default TRUE
+
 Alexey Kuznetsov.
 kuznet@ms2.inr.ac.ru