• Toshiaki Makita's avatar
    bridge: Change local fdb entries whenever mac address of bridge device changes · a4b816d8
    Toshiaki Makita authored
    Vlan code may need fdb change when changing mac address of bridge device
    even if it is caused by the mac address changing of a bridge port.
    
    Example configuration:
      ip link set eth0 address 12:34:56:78:90:ab
      ip link set eth1 address aa:bb:cc:dd:ee:ff
      brctl addif br0 eth0
      brctl addif br0 eth1 # br0 will have mac address 12:34:56:78:90:ab
      bridge vlan add dev br0 vid 10 self
      bridge vlan add dev eth0 vid 10
    We will have fdb entry such that f->dst == NULL, f->vlan_id == 10 and
    f->addr == 12:34:56:78:90:ab at this time.
    Next, change the mac address of eth0 to greater value.
      ip link set eth0 address ee:ff:12:34:56:78
    Then, mac address of br0 will be recalculated and set to aa:bb:cc:dd:ee:ff.
    However, an entry aa:bb:cc:dd:ee:ff will not be created and we will be not
    able to communicate using br0 on vlan 10.
    
    Address this issue by deleting and adding local entries whenever
    changing the mac address of the bridge device.
    
    If there already exists an entry that has the same address, for example,
    in case that br_fdb_changeaddr() has already inserted it,
    br_fdb_change_mac_address() will simply fail to insert it and no
    duplicated entry will be made, as it was.
    
    This approach also needs br_add_if() to call br_fdb_insert() before
    br_stp_recalculate_bridge_id() so that we don't create an entry whose
    dst == NULL in this function to preserve previous behavior.
    
    Note that this is a slight change in behavior where the bridge device can
    receive the traffic to the new address before calling
    br_stp_recalculate_bridge_id() in br_add_if().
    However, it is not a problem because we have already the address on the
    new port and such a way to insert new one before recalculating bridge id
    is taken in br_device_event() as well.
    Signed-off-by: default avatarToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
    Acked-by: default avatarVlad Yasevich <vyasevic@redhat.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    a4b816d8
br_stp_if.c 7.67 KB