Re: [PATCH net-next] net: bridge: add support for IGMP/MLD stats and export them via netlink

On 27/06/16 20:10, Nikolay Aleksandrov wrote:

This patch adds stats support for the currently used IGMP/MLD types by the
bridge. The stats are per-port (plus one stat per-bridge) and per-direction
(RX/TX). The stats are exported via netlink via the new linkxstats API
(RTM_GETSTATS). In order to minimize the performance impact, a new option
is used to enable/disable the stats - multicast_stats_enabled, similar to
the recent vlan stats. Also in order to avoid multiple IGMP/MLD type
lookups and checks, we make use of the current "igmp" member of the bridge
private skb->cb region to record the type on Rx (both host-generated and
external packets pass by multicast_rcv()). We can do that since the igmp
member was used as a boolean and all the valid IGMP/MLD types are positive
values. The normal bridge fast-path is not affected at all, the only
affected paths are the flooding ones and since we make use of the IGMP/MLD
type, we can quickly determine if the packet should be counted using
cache-hot data (cb's igmp member). We add counters for:
* IGMP Queries
* IGMP Leaves
* IGMP v1/v2/v3 reports

* MLD Queries
* MLD Leaves
* MLD v1/v2 reports

These are invaluable when monitoring or debugging complex multicast setups
with bridges.

Signed-off-by: Nikolay Aleksandrov <redacted>
---
 include/uapi/linux/if_bridge.h |  27 +++++++
 include/uapi/linux/if_link.h   |   1 +
 net/bridge/br_device.c         |  10 ++-
 net/bridge/br_forward.c        |  13 ++-
 net/bridge/br_if.c             |   9 ++-
 net/bridge/br_input.c          |   3 +
 net/bridge/br_multicast.c      | 176 +++++++++++++++++++++++++++++++++++++----
 net/bridge/br_netlink.c        |  94 ++++++++++++++++------
 net/bridge/br_private.h        |  41 +++++++++-
 net/bridge/br_sysfs_br.c       |  25 ++++++
 10 files changed, 356 insertions(+), 43 deletions(-)

Self-NAK, while the patch is okay, me and Roopa have been talking about exporting
the stats via the new API better and would like to introduce a way to expose only
per-port stats via a specific RTM_GETSTATS request instead of dumping it all via
the bridge request in order to be able to get the stats only for a single device.

I will post v2 after working out the details on how to achieve per-port export of
linkxstats.

Thanks,
 Nik