• Toshiaki Makita's avatar
    bridge: Fix the way to find old local fdb entries in br_fdb_changeaddr · a5642ab4
    Toshiaki Makita authored
    br_fdb_changeaddr() assumes that there is at most one local entry per port
    per vlan. It used to be true, but since commit 36fd2b63 ("bridge: allow
    creating/deleting fdb entries via netlink"), it has not been so.
    Therefore, the function might fail to search a correct previous address
    to be deleted and delete an arbitrary local entry if user has added local
    entries manually.
    
    Example of problematic case:
      ip link set eth0 address ee:ff:12:34:56:78
      brctl addif br0 eth0
      bridge fdb add 12:34:56:78:90:ab dev eth0 master
      ip link set eth0 address aa:bb:cc:dd:ee:ff
    Then, the address 12:34:56:78:90:ab might be deleted instead of
    ee:ff:12:34:56:78, the original mac address of eth0.
    
    Address this issue by introducing a new flag, added_by_user, to struct
    net_bridge_fdb_entry.
    
    Note that br_fdb_delete_by_port() has to set added_by_user to 0 in cases
    like:
      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
      bridge fdb add aa:bb:cc:dd:ee:ff dev eth0 master
      brctl addif br0 eth1
      brctl delif br0 eth0
    In this case, kernel should delete the user-added entry aa:bb:cc:dd:ee:ff,
    but it also should have been added by "brctl addif br0 eth1" originally,
    so we don't delete it and treat it a new kernel-created entry.
    Signed-off-by: default avatarToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    a5642ab4
br_fdb.c 19.8 KB