net: bridge: add support for IGMP/MLD stats and export them via netlink

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 <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 27 insertions, 0 deletions

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index 397d503fdedb..8304fe6f0561 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -247,8 +247,34 @@ enum {
 enum {
         BRIDGE_XSTATS_UNSPEC,
         BRIDGE_XSTATS_VLAN,
+        BRIDGE_XSTATS_MCAST,
+        BRIDGE_XSTATS_PAD,
         __BRIDGE_XSTATS_MAX
 };
 #define BRIDGE_XSTATS_MAX (__BRIDGE_XSTATS_MAX - 1)
 
+enum {
+        BR_MCAST_DIR_RX,
+        BR_MCAST_DIR_TX,
+        BR_MCAST_DIR_SIZE
+};
+
+/* IGMP/MLD statistics */
+struct br_mcast_stats {
+        __u64 igmp_queries[BR_MCAST_DIR_SIZE];
+        __u64 igmp_leaves[BR_MCAST_DIR_SIZE];
+        __u64 igmp_v1reports[BR_MCAST_DIR_SIZE];
+        __u64 igmp_v2reports[BR_MCAST_DIR_SIZE];
+        __u64 igmp_v3reports[BR_MCAST_DIR_SIZE];
+        __u64 igmp_parse_errors;
+
+        __u64 mld_queries[BR_MCAST_DIR_SIZE];
+        __u64 mld_leaves[BR_MCAST_DIR_SIZE];
+        __u64 mld_v1reports[BR_MCAST_DIR_SIZE];
+        __u64 mld_v2reports[BR_MCAST_DIR_SIZE];
+        __u64 mld_parse_errors;
+
+        __u64 mcast_bytes[BR_MCAST_DIR_SIZE];
+        __u64 mcast_packets[BR_MCAST_DIR_SIZE];
+};
 #endif /* _UAPI_LINUX_IF_BRIDGE_H */
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index db2458ade81c..4285ac31e865 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -273,6 +273,7 @@ enum {
         IFLA_BR_VLAN_DEFAULT_PVID,
         IFLA_BR_PAD,
         IFLA_BR_VLAN_STATS_ENABLED,
+        IFLA_BR_MCAST_STATS_ENABLED,
         __IFLA_BR_MAX,
 };