• dingtianhong's avatar
    bonding: correct the MAC address for "follow" fail_over_mac policy · e051e39d
    dingtianhong authored
    [ Upstream commit a951bc1e ]
    
    The "follow" fail_over_mac policy is useful for multiport devices that
    either become confused or incur a performance penalty when multiple
    ports are programmed with the same MAC address, but the same MAC
    address still may happened by this steps for this policy:
    
    1) echo +eth0 > /sys/class/net/bond0/bonding/slaves
       bond0 has the same mac address with eth0, it is MAC1.
    
    2) echo +eth1 > /sys/class/net/bond0/bonding/slaves
       eth1 is backup, eth1 has MAC2.
    
    3) ifconfig eth0 down
       eth1 became active slave, bond will swap MAC for eth0 and eth1,
       so eth1 has MAC1, and eth0 has MAC2.
    
    4) ifconfig eth1 down
       there is no active slave, and eth1 still has MAC1, eth2 has MAC2.
    
    5) ifconfig eth0 up
       the eth0 became active slave again, the bond set eth0 to MAC1.
    
    Something wrong here, then if you set eth1 up, the eth0 and eth1 will have the same
    MAC address, it will break this policy for ACTIVE_BACKUP mode.
    
    This patch will fix this problem by finding the old active slave and
    swap them MAC address before change active slave.
    Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
    Tested-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
    e051e39d
bond_main.c 128 KB