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, 3 insertions, 2 deletions

diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
index 006a7b81d758..4113916cc1bb 100644
--- a/include/net/rtnetlink.h
+++ b/include/net/rtnetlink.h
@@ -98,10 +98,11 @@ struct rtnl_link_ops {
                                                    const struct net_device *dev,
                                                    const struct net_device *slave_dev);
         struct net              *(*get_link_net)(const struct net_device *dev);
-        size_t                  (*get_linkxstats_size)(const struct net_device *dev);
+        size_t                  (*get_linkxstats_size)(const struct net_device *dev,
+                                                       int attr);
         int                     (*fill_linkxstats)(struct sk_buff *skb,
                                                    const struct net_device *dev,
-                                                   int *prividx);
+                                                   int *prividx, int attr);
 };
 
 int __rtnl_link_register(struct rtnl_link_ops *ops);