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>

1 files changed, 65 insertions, 26 deletions

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index ed75ff9ff9e6..f2a29e467e78 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -851,6 +851,7 @@ static const struct nla_policy br_policy[IFLA_BR_MAX + 1] = {
 	[IFLA_BR_NF_CALL_ARPTABLES] = { .type = NLA_U8 },
 	[IFLA_BR_VLAN_DEFAULT_PVID] = { .type = NLA_U16 },
 	[IFLA_BR_VLAN_STATS_ENABLED] = { .type = NLA_U8 },
+	[IFLA_BR_MCAST_STATS_ENABLED] = { .type = NLA_U8 },
 };
 
 static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
@@ -1055,6 +1056,13 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
 
 		br->multicast_startup_query_interval = clock_t_to_jiffies(val);
 	}
+
+	if (data[IFLA_BR_MCAST_STATS_ENABLED]) {
+		__u8 mcast_stats;
+
+		mcast_stats = nla_get_u8(data[IFLA_BR_MCAST_STATS_ENABLED]);
+		br->multicast_stats_enabled = !!mcast_stats;
+	}
 #endif
 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 	if (data[IFLA_BR_NF_CALL_IPTABLES]) {
@@ -1110,6 +1118,7 @@ static size_t br_get_size(const struct net_device *brdev)
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_SNOOPING */
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_QUERY_USE_IFADDR */
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_QUERIER */
+	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_MCAST_STATS_ENABLED */
 	       nla_total_size(sizeof(u32)) +    /* IFLA_BR_MCAST_HASH_ELASTICITY */
 	       nla_total_size(sizeof(u32)) +    /* IFLA_BR_MCAST_HASH_MAX */
 	       nla_total_size(sizeof(u32)) +    /* IFLA_BR_MCAST_LAST_MEMBER_CNT */
@@ -1187,6 +1196,8 @@ static int br_fill_info(struct sk_buff *skb, const struct net_device *brdev)
 	    nla_put_u8(skb, IFLA_BR_MCAST_QUERY_USE_IFADDR,
 		       br->multicast_query_use_ifaddr) ||
 	    nla_put_u8(skb, IFLA_BR_MCAST_QUERIER, br->multicast_querier) ||
+	    nla_put_u8(skb, IFLA_BR_MCAST_STATS_ENABLED,
+		       br->multicast_stats_enabled) ||
 	    nla_put_u32(skb, IFLA_BR_MCAST_HASH_ELASTICITY,
 			br->hash_elasticity) ||
 	    nla_put_u32(skb, IFLA_BR_MCAST_HASH_MAX, br->hash_max) ||
@@ -1242,21 +1253,21 @@ static size_t bridge_get_linkxstats_size(const struct net_device *dev)
 	int numvls = 0;
 
 	vg = br_vlan_group(br);
-	if (!vg)
-		return 0;
-
-	/* we need to count all, even placeholder entries */
-	list_for_each_entry(v, &vg->vlan_list, vlist)
-		numvls++;
+	if (vg) {
+		/* we need to count all, even placeholder entries */
+		list_for_each_entry(v, &vg->vlan_list, vlist)
+			numvls++;
+	}
 
-	/* account for the vlans and the link xstats type nest attribute */
 	return numvls * nla_total_size(sizeof(struct bridge_vlan_xstats)) +
+	       nla_total_size(sizeof(struct br_mcast_stats)) +
 	       nla_total_size(0);
 }
 
 static size_t brport_get_linkxstats_size(const struct net_device *dev)
 {
-	return nla_total_size(0);
+	return nla_total_size(sizeof(struct br_mcast_stats)) +
+	       nla_total_size(0);
 }
 
 static size_t br_get_linkxstats_size(const struct net_device *dev, int attr)
@@ -1280,37 +1291,50 @@ static int bridge_fill_linkxstats(struct sk_buff *skb,
 				  int *prividx)
 {
 	struct net_bridge *br = netdev_priv(dev);
+	struct nlattr *nla __maybe_unused;
 	struct net_bridge_vlan_group *vg;
 	struct net_bridge_vlan *v;
 	struct nlattr *nest;
 	int vl_idx = 0;
 
-	vg = br_vlan_group(br);
-	if (!vg)
-		goto out;
 	nest = nla_nest_start(skb, LINK_XSTATS_TYPE_BRIDGE);
 	if (!nest)
 		return -EMSGSIZE;
-	list_for_each_entry(v, &vg->vlan_list, vlist) {
-		struct bridge_vlan_xstats vxi;
-		struct br_vlan_stats stats;
 
-		if (++vl_idx < *prividx)
-			continue;
-		memset(&vxi, 0, sizeof(vxi));
-		vxi.vid = v->vid;
-		br_vlan_get_stats(v, &stats);
-		vxi.rx_bytes = stats.rx_bytes;
-		vxi.rx_packets = stats.rx_packets;
-		vxi.tx_bytes = stats.tx_bytes;
-		vxi.tx_packets = stats.tx_packets;
-
-		if (nla_put(skb, BRIDGE_XSTATS_VLAN, sizeof(vxi), &vxi))
+	vg = br_vlan_group(br);
+	if (vg) {
+		list_for_each_entry(v, &vg->vlan_list, vlist) {
+			struct bridge_vlan_xstats vxi;
+			struct br_vlan_stats stats;
+
+			if (++vl_idx < *prividx)
+				continue;
+			memset(&vxi, 0, sizeof(vxi));
+			vxi.vid = v->vid;
+			br_vlan_get_stats(v, &stats);
+			vxi.rx_bytes = stats.rx_bytes;
+			vxi.rx_packets = stats.rx_packets;
+			vxi.tx_bytes = stats.tx_bytes;
+			vxi.tx_packets = stats.tx_packets;
+
+			if (nla_put(skb, BRIDGE_XSTATS_VLAN, sizeof(vxi), &vxi))
+				goto nla_put_failure;
+		}
+	}
+
+#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
+	if (++vl_idx >= *prividx) {
+		nla = nla_reserve_64bit(skb, BRIDGE_XSTATS_MCAST,
+					sizeof(struct br_mcast_stats),
+					BRIDGE_XSTATS_PAD);
+		if (!nla)
 			goto nla_put_failure;
+		br_multicast_get_stats(br, NULL, nla_data(nla));
 	}
+#endif
 	nla_nest_end(skb, nest);
 	*prividx = 0;
-out:
+
 	return 0;
 
 nla_put_failure:
@@ -1324,11 +1348,26 @@ static int brport_fill_linkxstats(struct sk_buff *skb,
 				  const struct net_device *dev,
 				  int *prividx)
 {
+	struct net_bridge_port *p = br_port_get_rtnl(dev);
+	struct nlattr *nla __maybe_unused;
 	struct nlattr *nest;
 
+	if (!p)
+		return 0;
+
 	nest = nla_nest_start(skb, LINK_XSTATS_TYPE_BRIDGE);
 	if (!nest)
 		return -EMSGSIZE;
+#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
+	nla = nla_reserve_64bit(skb, BRIDGE_XSTATS_MCAST,
+				sizeof(struct br_mcast_stats),
+				BRIDGE_XSTATS_PAD);
+	if (!nla) {
+		nla_nest_end(skb, nest);
+		return -EMSGSIZE;
+	}
+	br_multicast_get_stats(p->br, p, nla_data(nla));
+#endif
 	nla_nest_end(skb, nest);
 
 	return 0;