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

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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: e36b9d16c6a6 ("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>
This commit is contained in:
Nikolay Aleksandrov 2023-03-15 13:18:40 +02:00 committed by David S. Miller
parent 53515a052a
commit 9ec7eb60dc
1 changed files with 15 additions and 4 deletions
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19
drivers/net/bonding/bond_main.c
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@ -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);