From 4c8755d69cbde2ec464a39c932aed0a83f9ff89f Mon Sep 17 00:00:00 2001 From: Linus Lüssing Date: Sat, 15 Feb 2014 17:47:54 +0100 Subject: batman-adv: Send multicast packets to nodes with a WANT_ALL flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit With this patch a node sends IPv4 multicast packets to nodes which have a BATADV_MCAST_WANT_ALL_IPV4 flag set and IPv6 multicast packets to nodes which have a BATADV_MCAST_WANT_ALL_IPV6 flag set, too. Why is this needed? There are scenarios involving bridges where multicast report snooping and multicast TT announcements are not sufficient, which would lead to packet loss for some nodes otherwise: MLDv1 and IGMPv1/IGMPv2 have a suppression mechanism for multicast listener reports. When we have an MLDv1/IGMPv1/IGMPv2 querier behind a bridge then our snooping bridge is potentially not going to see any reports even though listeners exist because according to RFC4541 such reports are only forwarded to multicast routers: ----------------------------------------------------------- --------------- {Querier}---|Snoop. Switch|----{Listener} --------------- \ ^ ------- | br0 | < ??? ------- \ _-~---~_ _-~/ ~-_ ~ batman-adv \-----{Sender} \~_ cloud ~/ -~~__-__-~_/ I) MLDv1 Query: {Querier} -> flooded II) MLDv1 Report: {Listener} -> {Querier} -> br0 cannot detect the {Listener} => Packets from {Sender} need to be forwarded to all detected listeners and MLDv1/IGMPv1/IGMPv2 queriers. ----------------------------------------------------------- Note that we do not need to explicitly forward to MLDv2/IGMPv3 queriers, because these protocols have no report suppression: A bridge has no trouble detecting MLDv2/IGMPv3 listeners. Even though we do not support bridges yet we need to provide the according infrastructure already to not break compatibility later. Signed-off-by: Linus Lüssing Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli --- net/batman-adv/send.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/batman-adv/send.c') diff --git a/net/batman-adv/send.c b/net/batman-adv/send.c index 8bee5e8536b7..3d64ed20c393 100644 --- a/net/batman-adv/send.c +++ b/net/batman-adv/send.c @@ -27,6 +27,7 @@ #include "originator.h" #include "network-coding.h" #include "fragmentation.h" +#include "multicast.h" static void batadv_send_outstanding_bcast_packet(struct work_struct *work); -- cgit v1.2.3-58-ga151