bonding: add netlink attributes to slave link dev

If link is IFF_SLAVE, extend link dev netlink attributes to include
slave attributes with new IFLA_SLAVE nest.  Add netlink notification
(RTM_NEWLINK) when slave status changes from backup to active, or
visa-versa.

Adds new ndo_get_slave op to net_device_ops to fill skb with IFLA_SLAVE
attributes.  Currently only used by bonding driver, but could be
used by other aggregating devices with slaves.

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

1 files changed, 54 insertions, 0 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e6e7d582f901..4f85de7aca33 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -721,6 +721,28 @@ static size_t rtnl_port_size(const struct net_device *dev)
 		return port_self_size;
 }
 
+static size_t rtnl_bond_slave_size(const struct net_device *dev)
+{
+	struct net_device *bond;
+	size_t slave_size =
+		nla_total_size(sizeof(struct nlattr)) +	/* IFLA_SLAVE */
+		nla_total_size(1) +	/* IFLA_SLAVE_STATE */
+		nla_total_size(1) +	/* IFLA_SLAVE_MII_STATUS */
+		nla_total_size(4) +	/* IFLA_SLAVE_LINK_FAILURE_COUNT */
+		nla_total_size(MAX_ADDR_LEN) +	/* IFLA_SLAVE_PERM_HWADDR */
+		nla_total_size(2) +	/* IFLA_SLAVE_QUEUE_ID */
+		nla_total_size(2) +	/* IFLA_SLAVE_AD_AGGREGATOR_ID */
+		0;
+
+	if (netif_is_bond_slave((struct net_device *)dev)) {
+		bond = netdev_master_upper_dev_get((struct net_device *)dev);
+		if (bond && bond->netdev_ops->ndo_get_slave)
+			return slave_size;
+	}
+
+	return 0;
+}
+
 static noinline size_t if_nlmsg_size(const struct net_device *dev,
 				     u32 ext_filter_mask)
 {
@@ -750,6 +772,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
 	       + rtnl_port_size(dev) /* IFLA_VF_PORTS + IFLA_PORT_SELF */
 	       + rtnl_link_get_size(dev) /* IFLA_LINKINFO */
 	       + rtnl_link_get_af_size(dev) /* IFLA_AF_SPEC */
+	       + rtnl_bond_slave_size(dev) /* IFLA_SLAVE */
 	       + nla_total_size(MAX_PHYS_PORT_ID_LEN); /* IFLA_PHYS_PORT_ID */
 }
 
@@ -847,6 +870,34 @@ static int rtnl_phys_port_id_fill(struct sk_buff *skb, struct net_device *dev)
 	return 0;
 }
 
+static size_t rtnl_bond_slave_fill(struct sk_buff *skb, struct net_device *dev)
+{
+	struct net_device *bond;
+	struct nlattr *nest;
+	int err;
+
+	if (!netif_is_bond_slave(dev))
+		return 0;
+
+	bond = netdev_master_upper_dev_get(dev);
+	if (!bond || !bond->netdev_ops->ndo_get_slave)
+		return 0;
+
+	nest = nla_nest_start(skb, IFLA_SLAVE);
+	if (!nest)
+		return -EMSGSIZE;
+
+	err = bond->netdev_ops->ndo_get_slave(dev, skb);
+	if (err) {
+		nla_nest_cancel(skb, nest);
+		return (err == -EMSGSIZE) ? err : 0;
+	}
+
+	nla_nest_end(skb, nest);
+
+	return 0;
+}
+
 static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 			    int type, u32 pid, u32 seq, u32 change,
 			    unsigned int flags, u32 ext_filter_mask)
@@ -1001,6 +1052,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 	if (rtnl_port_fill(skb, dev))
 		goto nla_put_failure;
 
+	if (rtnl_bond_slave_fill(skb, dev))
+		goto nla_put_failure;
+
 	if (dev->rtnl_link_ops) {
 		if (rtnl_link_fill(skb, dev) < 0)
 			goto nla_put_failure;