#6527 NORM Never A: Mesh does not forward multicast packets (most of the time)

[Zarro Boogs per Child]

#6527: Mesh does not forward multicast packets (most of the time)
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 Reporter:  gnu     |       Owner:  dilinger                         
     Type:  defect  |      Status:  new                              
 Priority:  normal  |   Milestone:  Never Assigned                   
Component:  kernel  |     Version:  Development build as of this date
 Keywords:          |    Verified:  0                                
 Blocking:          |   Blockedby:                                   
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 I found this bug while trying to reproduce #4616 on modern hardware and
 software.

  Setup:

   * Two XO's, MP G1G1s.  One is using build 656, the other update.1-691.

   * In !NetworkManager screen, put both on "Mesh Network 1".  Wait a
 few minutes for things to settle down.  Go to donut screen, make     sure
 both of them say "Mesh Network 1, Connected to a Simple Mesh".

   * Start a terminal on each laptop.  Become root.

   * "ping6 -I msh0 ff02::1" on each laptop.

   * This will ping the all-nodes multicast address.  The laptop that
 sends this should get back a unicast IPv6 ping response from each     node
 on the network.  Keep moving the mouse on the update.1-691 laptop to avoid
 suspending.

   * On each laptop, it can see itself (btw, ping6 prints its own
 address on its first line of output).  It prints a very low   latency
 response (e.g. 0.154 ms) packet from its own kernel.  It    seldom or
 never sees a ping response from the other laptop.


   * Bizarrely, every once in a while, the Build 656 laptop will see
 ping responses from the update.1-691 laptop.  For about 10 seconds.
 Then they will go away again.  They say "(DUP!)" because it's the
 second response packet from a single outgoing ping packet.  Perhaps
 these happen after it suspends and I resume it with mouse motion.

 If I stop the pings, go back into !NetworkManager, and associate both XO's
 with a local access point (TrendNET TEW432-BRP), replace "msh0" with
 "eth0" in the ping6 command, and rerun the test, then the test works.
 Each laptop can see the other's multicast ping packets.

 This could be a kernel problem, or could be a Libertas firmware problem.
 I'm starting reporting it as kernel problem (partly because there's no
 category for mesh or Libertas bugs).  It should be possible to produce a
 smoking gun in kernel logs, that show whether the chip ever gives the
 kernel the missing packets.

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Ticket URL: <http://dev.laptop.org/ticket/6527>
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