• stephen hemminger's avatar
    bridge: send proper message_age in config BPDU · bde99f60
    stephen hemminger authored
    commit 0c03150e upstream.
    
    A bridge topology with three systems:
    
          +------+  +------+
          | A(2) |--| B(1) |
          +------+  +------+
               \    /
              +------+
              | C(3) |
              +------+
    
    What is supposed to happen:
     * bridge with the lowest ID is elected root (for example: B)
     * C detects that A->C is higher cost path and puts in blocking state
    
    What happens. Bridge with lowest id (B) is elected correctly as
    root and things start out fine initially. But then config BPDU
    doesn't get transmitted from A -> C. Because of that
    the link from A-C is transistioned to the forwarding state.
    
    The root cause of this is that the configuration messages
    is generated with bogus message age, and dropped before
    sending.
    
    In the standardmessage_age is supposed to be:
      the time since the generation of the Configuration BPDU by
      the Root that instigated the generation of this Configuration BPDU.
    
    Reimplement this by recording the timestamp (age + jiffies) when
    recording config information. The old code incorrectly used the time
    elapsed on the ageing timer which was incorrect.
    
    See also:
      https://bugzilla.vyatta.com/show_bug.cgi?id=7164Signed-off-by: default avatarStephen Hemminger <shemminger@vyatta.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
    bde99f60
br_private.h 15.3 KB