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>

3 files changed, 46 insertions, 2 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index df85cec3e5d..3220b488dd1 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3883,6 +3883,7 @@ static const struct net_device_ops bond_netdev_ops = {
 #endif
 	.ndo_add_slave		= bond_enslave,
 	.ndo_del_slave		= bond_release,
+	.ndo_get_slave		= bond_get_slave,
 	.ndo_fix_features	= bond_fix_features,
 };
 
diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c
index 555c7837d8e..21c648854a8 100644
--- a/drivers/net/bonding/bond_netlink.c
+++ b/drivers/net/bonding/bond_netlink.c
@@ -22,6 +22,42 @@
 #include <linux/reciprocal_div.h>
 #include "bonding.h"
 
+int bond_get_slave(struct net_device *slave_dev, struct sk_buff *skb)
+{
+	struct slave *slave = bond_slave_get_rtnl(slave_dev);
+	const struct aggregator *agg;
+
+	if (nla_put_u8(skb, IFLA_SLAVE_STATE, bond_slave_state(slave)))
+		goto nla_put_failure;
+
+	if (nla_put_u8(skb, IFLA_SLAVE_MII_STATUS, slave->link))
+		goto nla_put_failure;
+
+	if (nla_put_u32(skb, IFLA_SLAVE_LINK_FAILURE_COUNT,
+			slave->link_failure_count))
+		goto nla_put_failure;
+
+	if (nla_put(skb, IFLA_SLAVE_PERM_HWADDR,
+		    slave_dev->addr_len, slave->perm_hwaddr))
+		goto nla_put_failure;
+
+	if (nla_put_u16(skb, IFLA_SLAVE_QUEUE_ID, slave->queue_id))
+		goto nla_put_failure;
+
+	if (slave->bond->params.mode == BOND_MODE_8023AD) {
+		agg = SLAVE_AD_INFO(slave).port.aggregator;
+		if (agg)
+			if (nla_put_u16(skb, IFLA_SLAVE_AD_AGGREGATOR_ID,
+					agg->aggregator_identifier))
+				goto nla_put_failure;
+	}
+
+	return 0;
+
+nla_put_failure:
+	return -EMSGSIZE;
+}
+
 static const struct nla_policy bond_policy[IFLA_BOND_MAX + 1] = {
 	[IFLA_BOND_MODE]		= { .type = NLA_U8 },
 	[IFLA_BOND_ACTIVE_SLAVE]	= { .type = NLA_U32 },
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 309757d8482..8a935f8f2b3 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -285,12 +285,18 @@ static inline bool bond_is_lb(const struct bonding *bond)
 
 static inline void bond_set_active_slave(struct slave *slave)
 {
-	slave->backup = 0;
+	if (slave->backup) {
+		slave->backup = 0;
+		rtmsg_ifinfo(RTM_NEWLINK, slave->dev, 0, GFP_KERNEL);
+	}
 }
 
 static inline void bond_set_backup_slave(struct slave *slave)
 {
-	slave->backup = 1;
+	if (!slave->backup) {
+		slave->backup = 1;
+		rtmsg_ifinfo(RTM_NEWLINK, slave->dev, 0, GFP_KERNEL);
+	}
 }
 
 static inline int bond_slave_state(struct slave *slave)
@@ -426,6 +432,7 @@ int bond_sysfs_slave_add(struct slave *slave);
 void bond_sysfs_slave_del(struct slave *slave);
 int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev);
 int bond_release(struct net_device *bond_dev, struct net_device *slave_dev);
+int bond_get_slave(struct net_device *slave_dev, struct sk_buff *skb);
 int bond_xmit_hash(struct bonding *bond, struct sk_buff *skb, int count);
 int bond_parse_parm(const char *mode_arg, const struct bond_parm_tbl *tbl);
 int bond_parm_tbl_lookup(int mode, const struct bond_parm_tbl *tbl);