net: rtnetlink: add support for the IFLA_STATS_LINK_XSTATS_SLAVE attribute

This patch adds support for the IFLA_STATS_LINK_XSTATS_SLAVE attribute
which allows to export per-slave statistics if the master device supports
the linkxstats callback. The attribute is passed down to the linkxstats
callback and it is up to the callback user to use it (an example has been
added to the only current user - the bridge). This allows us to query only
specific slaves of master devices like bridge ports and export only what
we're interested in instead of having to dump all ports and searching only
for a single one. This will be used to export per-port IGMP/MLD stats and
also per-port vlan stats in the future, possibly other statistics as well.

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

1 files changed, 48 insertions, 2 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index eb49ca2..cfed7bc 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3519,7 +3519,32 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb, struct net_device *dev,
 			if (!attr)
 				goto nla_put_failure;
 
-			err = ops->fill_linkxstats(skb, dev, prividx);
+			err = ops->fill_linkxstats(skb, dev, prividx, *idxattr);
+			nla_nest_end(skb, attr);
+			if (err)
+				goto nla_put_failure;
+			*idxattr = 0;
+		}
+	}
+
+	if (stats_attr_valid(filter_mask, IFLA_STATS_LINK_XSTATS_SLAVE,
+			     *idxattr)) {
+		const struct rtnl_link_ops *ops = NULL;
+		const struct net_device *master;
+
+		master = netdev_master_upper_dev_get(dev);
+		if (master)
+			ops = master->rtnl_link_ops;
+		if (ops && ops->fill_linkxstats) {
+			int err;
+
+			*idxattr = IFLA_STATS_LINK_XSTATS_SLAVE;
+			attr = nla_nest_start(skb,
+					      IFLA_STATS_LINK_XSTATS_SLAVE);
+			if (!attr)
+				goto nla_put_failure;
+
+			err = ops->fill_linkxstats(skb, dev, prividx, *idxattr);
 			nla_nest_end(skb, attr);
 			if (err)
 				goto nla_put_failure;
@@ -3555,14 +3580,35 @@ static size_t if_nlmsg_stats_size(const struct net_device *dev,
 
 	if (stats_attr_valid(filter_mask, IFLA_STATS_LINK_XSTATS, 0)) {
 		const struct rtnl_link_ops *ops = dev->rtnl_link_ops;
+		int attr = IFLA_STATS_LINK_XSTATS;
 
 		if (ops && ops->get_linkxstats_size) {
-			size += nla_total_size(ops->get_linkxstats_size(dev));
+			size += nla_total_size(ops->get_linkxstats_size(dev,
+									attr));
 			/* for IFLA_STATS_LINK_XSTATS */
 			size += nla_total_size(0);
 		}
 	}
 
+	if (stats_attr_valid(filter_mask, IFLA_STATS_LINK_XSTATS_SLAVE, 0)) {
+		struct net_device *_dev = (struct net_device *)dev;
+		const struct rtnl_link_ops *ops = NULL;
+		const struct net_device *master;
+
+		/* netdev_master_upper_dev_get can't take const */
+		master = netdev_master_upper_dev_get(_dev);
+		if (master)
+			ops = master->rtnl_link_ops;
+		if (ops && ops->get_linkxstats_size) {
+			int attr = IFLA_STATS_LINK_XSTATS_SLAVE;
+
+			size += nla_total_size(ops->get_linkxstats_size(dev,
+									attr));
+			/* for IFLA_STATS_LINK_XSTATS_SLAVE */
+			size += nla_total_size(0);
+		}
+	}
+
 	return size;
 }