Commit 9ec7eb60 authored Mar 15, 2023 by Nikolay Aleksandrov Committed by David S. Miller Mar 17, 2023

bonding: restore IFF_MASTER/SLAVE flags on bond enslave ether type change



Add bond_ether_setup helper which is used to fix ether_setup() calls in the
bonding driver. It takes care of both IFF_MASTER and IFF_SLAVE flags, the
former is always restored and the latter only if it was set.
If the bond enslaves non-ARPHRD_ETHER device (changes its type), then
releases it and enslaves ARPHRD_ETHER device (changes back) then we
use ether_setup() to restore the bond device type but it also resets its
flags and removes IFF_MASTER and IFF_SLAVE[1]. Use the bond_ether_setup
helper to restore both after such transition.

[1] reproduce (nlmon is non-ARPHRD_ETHER):
 $ ip l add nlmon0 type nlmon
 $ ip l add bond2 type bond mode active-backup
 $ ip l set nlmon0 master bond2
 $ ip l set nlmon0 nomaster
 $ ip l add bond1 type bond
 (we use bond1 as ARPHRD_ETHER device to restore bond2's mode)
 $ ip l set bond1 master bond2
 $ ip l sh dev bond2
 37: bond2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether be:d7:c5:40:5b:cc brd ff:ff:ff:ff:ff:ff promiscuity 0 minmtu 68 maxmtu 1500
 (notice bond2's IFF_MASTER is missing)

Fixes: e36b9d16 ("bonding: clean muticast addresses when device changes type")
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 53515a05

drivers/net/bonding/bond_main.c

+15 −4

Original line number	Diff line number	Diff line
		@@ -1775,6 +1775,19 @@ void bond_lower_state_changed(struct slave *slave)
		slave_err(bond_dev, slave_dev, "Error: %s\n", errmsg); \
		} while (0)

		/* The bonding driver uses ether_setup() to convert a master bond device
		* to ARPHRD_ETHER, that resets the target netdevice's flags so we always
		* have to restore the IFF_MASTER flag, and only restore IFF_SLAVE if it was set
		*/
		static void bond_ether_setup(struct net_device *bond_dev)
		{
		unsigned int slave_flag = bond_dev->flags & IFF_SLAVE;

		ether_setup(bond_dev);
		bond_dev->flags \|= IFF_MASTER \| slave_flag;
		bond_dev->priv_flags &= ~IFF_TX_SKB_SHARING;
		}

		/* enslave device <slave> to bond device <master> */
		int bond_enslave(struct net_device bond_dev, struct net_device slave_dev,
		struct netlink_ext_ack *extack)
		@@ -1866,10 +1879,8 @@ int bond_enslave(struct net_device bond_dev, struct net_device slave_dev,

		if (slave_dev->type != ARPHRD_ETHER)
		bond_setup_by_slave(bond_dev, slave_dev);
		else {
		ether_setup(bond_dev);
		bond_dev->priv_flags &= ~IFF_TX_SKB_SHARING;
		}
		else
		bond_ether_setup(bond_dev);

		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
		bond_dev);