Re: [B.A.T.M.A.N.] [PATCHv15 1/4] batman-adv: Always flood IGMP/MLD reports

[Marek Lindner <mareklindner@neomailbox.ch>]

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On Tuesday, May 10, 2016 18:41:24 Linus Lüssing wrote:
> With this patch IGMP or MLD reports are always flooded. This is
> necessary for the upcoming bridge integration to function without
> multicast packet loss.
> 
> With the report handling so far bridges might miss interested multicast
> listeners, leading to wrongly excluding ports from multicast packet
> forwarding.
> 
> Currently we are treating IGMP/MLD reports, the messages bridges use to
> learn about interested multicast listeners, just as any other multicast
> packet: We try to send them to nodes matching its multicast destination.
> 
> Unfortunately, the destination address of reports of the older
> IGMPv2/MLDv1 protocol families do not strictly adhere to their own
> protocol: More precisely, the interested receiver, an IGMPv2 or MLDv1
> querier, itself usually does not listen to the multicast destination
> address of any reports.
> 
> Therefore with this patch we are simply excluding IGMP/MLD reports from
> the multicast forwarding code path and keep flooding them. By that
> any bridge receives them and can properly learn about listeners.
> 
> To avoid compatibility issues with older nodes not yet implementing this
> report handling, we need to force them to flood reports: We do this by
> bumping the multicast TVLV version to 2, effectively disabling their
> multicast optimization.
> 
> Tested-by: Simon Wunderlich <sw@simonwunderlich.de>
> Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
> ---
>  Makefile                              |    4 +
>  compat-include/linux/igmp.h           |   13 ++
>  compat-include/linux/skbuff.h         |   14 ++
>  compat-include/net/addrconf.h         |   13 ++
>  compat-include/net/ip6_checksum.h     |   18 +++
>  compat-include/net/ipv6.h             |   17 +++
>  compat-sources/Makefile               |    3 +
>  compat-sources/net/core/skbuff.c      |  212 +++++++++++++++++++++++++++++
>  compat-sources/net/ipv4/igmp.c        |  241
> +++++++++++++++++++++++++++++++++ compat-sources/net/ipv6/mcast_snoop.c
> |  216 +++++++++++++++++++++++++++++
> net/batman-adv/Kconfig                |    2 +-
>  net/batman-adv/multicast.c            |   85 ++++++++++--
>  12 files changed, 825 insertions(+), 13 deletions(-)
>  create mode 100644 compat-include/linux/igmp.h
>  create mode 100644 compat-include/net/addrconf.h
>  create mode 100644 compat-include/net/ip6_checksum.h
>  create mode 100644 compat-include/net/ipv6.h
>  create mode 100644 compat-sources/Makefile
>  create mode 100644 compat-sources/net/core/skbuff.c
>  create mode 100644 compat-sources/net/ipv4/igmp.c
>  create mode 100644 compat-sources/net/ipv6/mcast_snoop.c

Applied in revision 08bf4dc.

Thanks,
Marek

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