1. 29 Jul, 2019 19 commits
  2. 27 Jul, 2019 16 commits
  3. 26 Jul, 2019 3 commits
  4. 25 Jul, 2019 2 commits
    • David S. Miller's avatar
      Merge branch 'tipc-link-changeover-issues' · b591c6f6
      David S. Miller authored
      Tuong Lien says:
      
      ====================
      tipc: link changeover issues
      
      This patch series is to resolve some issues found with the current link
      changeover mechanism, it also includes an optimization for the link
      synching.
      ====================
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b591c6f6
    • Tuong Lien's avatar
      tipc: fix changeover issues due to large packet · 2320bcda
      Tuong Lien authored
      In conjunction with changing the interfaces' MTU (e.g. especially in
      the case of a bonding) where the TIPC links are brought up and down
      in a short time, a couple of issues were detected with the current link
      changeover mechanism:
      
      1) When one link is up but immediately forced down again, the failover
      procedure will be carried out in order to failover all the messages in
      the link's transmq queue onto the other working link. The link and node
      state is also set to FAILINGOVER as part of the process. The message
      will be transmited in form of a FAILOVER_MSG, so its size is plus of 40
      bytes (= the message header size). There is no problem if the original
      message size is not larger than the link's MTU - 40, and indeed this is
      the max size of a normal payload messages. However, in the situation
      above, because the link has just been up, the messages in the link's
      transmq are almost SYNCH_MSGs which had been generated by the link
      synching procedure, then their size might reach the max value already!
      When the FAILOVER_MSG is built on the top of such a SYNCH_MSG, its size
      will exceed the link's MTU. As a result, the messages are dropped
      silently and the failover procedure will never end up, the link will
      not be able to exit the FAILINGOVER state, so cannot be re-established.
      
      2) The same scenario above can happen more easily in case the MTU of
      the links is set differently or when changing. In that case, as long as
      a large message in the failure link's transmq queue was built and
      fragmented with its link's MTU > the other link's one, the issue will
      happen (there is no need of a link synching in advance).
      
      3) The link synching procedure also faces with the same issue but since
      the link synching is only started upon receipt of a SYNCH_MSG, dropping
      the message will not result in a state deadlock, but it is not expected
      as design.
      
      The 1) & 3) issues are resolved by the last commit that only a dummy
      SYNCH_MSG (i.e. without data) is generated at the link synching, so the
      size of a FAILOVER_MSG if any then will never exceed the link's MTU.
      
      For the 2) issue, the only solution is trying to fragment the messages
      in the failure link's transmq queue according to the working link's MTU
      so they can be failovered then. A new function is made to accomplish
      this, it will still be a TUNNEL PROTOCOL/FAILOVER MSG but if the
      original message size is too large, it will be fragmented & reassembled
      at the receiving side.
      Acked-by: default avatarYing Xue <ying.xue@windriver.com>
      Acked-by: default avatarJon Maloy <jon.maloy@ericsson.com>
      Signed-off-by: default avatarTuong Lien <tuong.t.lien@dektech.com.au>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2320bcda