Merge branch 'net-add-iff_no_addrconf-to-prevent-ipv6-addrconf'

Xin Long says:

====================
net: add IFF_NO_ADDRCONF to prevent ipv6 addrconf

This patchset adds IFF_NO_ADDRCONF flag for dev->priv_flags
to prevent ipv6 addrconf, as Jiri Pirko's suggestion.

For Bonding it changes to use this flag instead of IFF_SLAVE
flag in Patch 1, and for Teaming and Net Failover it sets
this flag before calling dev_open() in Patch 2 and 3.
====================

Link: https://lore.kernel.org/r/cover.1670599241.git.lucien.xin@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/bonding/bond_main.c

@@ -1632,13 +1632,19 @@ static int bond_master_upper_dev_link(struct bonding *bond, struct slave *slave,
 {
 	struct netdev_lag_upper_info lag_upper_info;
 	enum netdev_lag_tx_type type;
+	int err;
 
 	type = bond_lag_tx_type(bond);
 	lag_upper_info.tx_type = type;
 	lag_upper_info.hash_type = bond_lag_hash_type(bond, type);
 
-	return netdev_master_upper_dev_link(slave->dev, bond->dev, slave,
-					    &lag_upper_info, extack);
+	err = netdev_master_upper_dev_link(slave->dev, bond->dev, slave,
+					   &lag_upper_info, extack);
+	if (err)
+		return err;
+
+	slave->dev->flags |= IFF_SLAVE;
+	return 0;
 }
 
 static void bond_upper_dev_unlink(struct bonding *bond, struct slave *slave)
@@ -1950,8 +1956,8 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev,
 		}
 	}
 
-	/* set slave flag before open to prevent IPv6 addrconf */
-	slave_dev->flags |= IFF_SLAVE;
+	/* set no_addrconf flag before open to prevent IPv6 addrconf */
+	slave_dev->priv_flags |= IFF_NO_ADDRCONF;
 
 	/* open the slave since the application closed it */
 	res = dev_open(slave_dev, extack);
@@ -2254,7 +2260,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev,
 	dev_close(slave_dev);
 
 err_restore_mac:
-	slave_dev->flags &= ~IFF_SLAVE;
+	slave_dev->priv_flags &= ~IFF_NO_ADDRCONF;
 	if (!bond->params.fail_over_mac ||
 	    BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {
 		/* XXX TODO - fom follow mode needs to change master's
@@ -2446,6 +2452,8 @@ static int __bond_release_one(struct net_device *bond_dev,
 	/* close slave before restoring its mac address */
 	dev_close(slave_dev);
 
+	slave_dev->priv_flags &= ~IFF_NO_ADDRCONF;
+
 	if (bond->params.fail_over_mac != BOND_FOM_ACTIVE ||
 	    BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {
 		/* restore original ("permanent") mac address */

drivers/net/team/team.c

@@ -1044,6 +1044,7 @@ static int team_port_enter(struct team *team, struct team_port *port)
 			goto err_port_enter;
 		}
 	}
+	port->dev->priv_flags |= IFF_NO_ADDRCONF;
 
 	return 0;
 
@@ -1057,6 +1058,7 @@ static void team_port_leave(struct team *team, struct team_port *port)
 {
 	if (team->ops.port_leave)
 		team->ops.port_leave(team, port);
+	port->dev->priv_flags &= ~IFF_NO_ADDRCONF;
 	dev_put(team->dev);
 }
 

include/linux/netdevice.h

@@ -1662,6 +1662,7 @@ struct net_device_ops {
  * @IFF_FAILOVER: device is a failover master device
  * @IFF_FAILOVER_SLAVE: device is lower dev of a failover master device
  * @IFF_L3MDEV_RX_HANDLER: only invoke the rx handler of L3 master device
+ * @IFF_NO_ADDRCONF: prevent ipv6 addrconf
  * @IFF_TX_SKB_NO_LINEAR: device/driver is capable of xmitting frames with
  *	skb_headlen(skb) == 0 (data starts from frag0)
  * @IFF_CHANGE_PROTO_DOWN: device supports setting carrier via IFLA_PROTO_DOWN
@@ -1697,7 +1698,7 @@ enum netdev_priv_flags {
 	IFF_FAILOVER			= 1<<27,
 	IFF_FAILOVER_SLAVE		= 1<<28,
 	IFF_L3MDEV_RX_HANDLER		= 1<<29,
-	/* was IFF_LIVE_RENAME_OK */
+	IFF_NO_ADDRCONF			= BIT_ULL(30),
 	IFF_TX_SKB_NO_LINEAR		= BIT_ULL(31),
 	IFF_CHANGE_PROTO_DOWN		= BIT_ULL(32),
 };

net/core/failover.c

@@ -80,14 +80,14 @@ static int failover_slave_register(struct net_device *slave_dev)
 		goto err_upper_link;
 	}
 
-	slave_dev->priv_flags |= IFF_FAILOVER_SLAVE;
+	slave_dev->priv_flags |= (IFF_FAILOVER_SLAVE | IFF_NO_ADDRCONF);
 
 	if (fops && fops->slave_register &&
 	    !fops->slave_register(slave_dev, failover_dev))
 		return NOTIFY_OK;
 
 	netdev_upper_dev_unlink(slave_dev, failover_dev);
-	slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE;
+	slave_dev->priv_flags &= ~(IFF_FAILOVER_SLAVE | IFF_NO_ADDRCONF);
 err_upper_link:
 	netdev_rx_handler_unregister(slave_dev);
 done:
@@ -121,7 +121,7 @@ int failover_slave_unregister(struct net_device *slave_dev)
 
 	netdev_rx_handler_unregister(slave_dev);
 	netdev_upper_dev_unlink(slave_dev, failover_dev);
-	slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE;
+	slave_dev->priv_flags &= ~(IFF_FAILOVER_SLAVE | IFF_NO_ADDRCONF);
 
 	if (fops && fops->slave_unregister &&
 	    !fops->slave_unregister(slave_dev, failover_dev))

net/ipv6/addrconf.c

@@ -3320,7 +3320,7 @@ static void addrconf_addr_gen(struct inet6_dev *idev, bool prefix_route)
 		return;
 
 	/* no link local addresses on devices flagged as slaves */
-	if (idev->dev->flags & IFF_SLAVE)
+	if (idev->dev->priv_flags & IFF_NO_ADDRCONF)
 		return;
 
 	ipv6_addr_set(&addr, htonl(0xFE800000), 0, 0, 0);
@@ -3560,7 +3560,7 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
 		if (idev && idev->cnf.disable_ipv6)
 			break;
 
-		if (dev->flags & IFF_SLAVE) {
+		if (dev->priv_flags & IFF_NO_ADDRCONF) {
 			if (event == NETDEV_UP && !IS_ERR_OR_NULL(idev) &&
 			    dev->flags & IFF_UP && dev->flags & IFF_MULTICAST)
 				ipv6_mc_up(idev);