net: rtnetlink: add linkxstats callbacks and attribute

Add callbacks to calculate the size and fill link extended statistics
which can be split into multiple messages and are dumped via the new
rtnl stats API (RTM_GETSTATS) with the IFLA_STATS_LINK_XSTATS attribute.
Also add that attribute to the idx mask check since it is expected to
be able to save state and resume dumping (e.g. future bridge per-vlan
stats will be dumped via this attribute and callbacks).
Each link type should nest its private attributes under the per-link type
attribute. This allows to have any number of separated private attributes
and to avoid one call to get the dev link type.

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

1 files changed, 30 insertions, 0 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index de529a20cd18..d471f097c739 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3483,6 +3483,26 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb, struct net_device *dev,
 		dev_get_stats(dev, sp);
 	}
 
+	if (stats_attr_valid(filter_mask, IFLA_STATS_LINK_XSTATS, *idxattr)) {
+		const struct rtnl_link_ops *ops = dev->rtnl_link_ops;
+
+		if (ops && ops->fill_linkxstats) {
+			int err;
+
+			*idxattr = IFLA_STATS_LINK_XSTATS;
+			attr = nla_nest_start(skb,
+					      IFLA_STATS_LINK_XSTATS);
+			if (!attr)
+				goto nla_put_failure;
+
+			err = ops->fill_linkxstats(skb, dev, prividx);
+			nla_nest_end(skb, attr);
+			if (err)
+				goto nla_put_failure;
+			*idxattr = 0;
+		}
+	}
+
 	nlmsg_end(skb, nlh);
 
 	return 0;
@@ -3509,6 +3529,16 @@ static size_t if_nlmsg_stats_size(const struct net_device *dev,
 	if (stats_attr_valid(filter_mask, IFLA_STATS_LINK_64, 0))
 		size += nla_total_size_64bit(sizeof(struct rtnl_link_stats64));
 
+	if (stats_attr_valid(filter_mask, IFLA_STATS_LINK_XSTATS, 0)) {
+		const struct rtnl_link_ops *ops = dev->rtnl_link_ops;
+
+		if (ops && ops->get_linkxstats_size) {
+			size += nla_total_size(ops->get_linkxstats_size(dev));
+			/* for IFLA_STATS_LINK_XSTATS */
+			size += nla_total_size(0);
+		}
+	}
+
 	return size;
 }