This is a WIP patchset i would like comments on from bridge, switchdev and hardware offload people. The linux bridge supports IGMP snooping. It will listen to IGMP reports on bridge ports and keep track of which groups have been joined on an interface. It will then forward multicast based on this group membership. When the bridge adds or removed groups from an interface, it uses switchdev to request the hardware add an mdb to a port, so the hardware can perform the selective forwarding between ports. What is not covered by the current bridge code, is IGMP joins/leaves from the host on the brX interface. No such monitoring is performed. With a pure software bridge, it is not required. All mulitcast frames are passed to the brX interface, and the network stack filters them, as it does for any interface. However, when hardware offload is involved, things change. We should program the hardware to only send multcast packets to the host when the host has in interest in them. Thus we need to perform IGMP snooping on the brX interface, just like any other interface of the bridge. However, currently the brX interface is missing all the needed data structures to do this. There is no net_bridge_port structure for the brX interface. This strucuture is created when an interface is added to the bridge. But the brX interface is not a member of the bridge. So this patchset makes the brX interface a first class member of the bridge. When the brX interface is opened, the interface is added to the bridge. A net_bridge_port is allocated for it, and IGMP snooping is performed as usual. There are some complexities here. Some assumptions are broken, like the master interface of a port interface is the bridge interface. The brX interface cannot be its own master. The use of netdev_master_upper_dev_get() within the bridge code has been changed to reflecit this. The bridge receive handler needs to not process frames for the brX interface, etc. The interface downward to the hardware is also an issue. The code presented here is a hack and needs to change. But that is secondary and can be solved once it is agreed how the bridge needs to change to support this use case. Comment welcome and wanted. Andrew Andrew Lunn (5): net: rtnetlink: Handle bridge port without upper device net: bridge: Skip receive handler on brX interface net: bridge: Make the brX interface a member of the bridge net: dsa: HACK: Handle MDB add/remove for none-switch ports net: dsa: Don't include CPU port when adding MDB to a port include/linux/if_bridge.h | 1 + net/bridge/br_device.c | 12 ++++++++++-- net/bridge/br_if.c | 37 ++++++++++++++++++++++++------------- net/bridge/br_input.c | 4 ++++ net/bridge/br_mdb.c | 2 -- net/bridge/br_multicast.c | 7 ++++--- net/bridge/br_private.h | 1 + net/core/rtnetlink.c | 23 +++++++++++++++++++++-- net/dsa/port.c | 19 +++++++++++++++++-- net/dsa/switch.c | 2 +- 10 files changed, 83 insertions(+), 25 deletions(-) -- 2.14.1
