#3593 NORM Trial-3: Mesh channel randomization breaks NM 'mesh-start' tweakable

[Dan Williams]

On Wed, 2007-09-19 at 06:18 -0400, Walter Bender wrote:
> I would recommend not making the patch; I think I found it confusing
> only because I didn't know that random impacted link-local. But do we
> still default to channel 1 if no school server is found?

No, I'm not confident that we do.

Dan


> -walter
> 
> On 9/18/07, Zarro Boogs per Child <bugtracker at laptop.org> wrote:
> > #3593: Mesh channel randomization breaks NM 'mesh-start' tweakable
> > -----------------------------+----------------------------------------------
> >  Reporter:  dcbw             |       Owner:  jg
> >      Type:  defect           |      Status:  new
> >  Priority:  normal           |   Milestone:  Trial-3
> > Component:  network manager  |     Version:
> >  Keywords:                   |    Verified:  0
> > -----------------------------+----------------------------------------------
> >  Since we switched back to randomized mesh channels two weeks ago at the
> >  request of the server team, this inadvertently broke expectations about
> >  how the /etc/NetworkManager/mesh-start file affects things when using
> >  local-only.  In this case, if you do local-only through mesh-start, you
> >  are not guaranteed to come up on channel 1 because the start channel is
> >  random.
> >
> >  Please determine if this is trial-3 material or not.  Obviously, the
> >  factors against fixing this for trial-3 are that:
> >
> >  1) our target users for trial 3 aren't expected to have to do this
> >  2) you can always switch directly to mesh-1 from the UI
> >  3) we are in code freeze
> >
> >  However, the fix is low-risk and does not affect normal codepaths.
> >
> >  ```
> >  Index: src/nm-device-802-11-mesh-olpc.c
> >  ===================================================================
> >  --- src/nm-device-802-11-mesh-olpc.c    (revision 2824)
> >  +++ src/nm-device-802-11-mesh-olpc.c    (working copy)
> >  @@ -459,7 +459,10 @@
> >                  self->priv->use_mesh_beacons = TRUE;
> >          }
> >
> >  -       self->priv->channel = get_random_channel ();
> >  +       if (self->priv->default_first_step == MESH_S4_P2P_MESH)
> >  +               self->priv->channel = 1;
> >  +       else
> >  +               self->priv->channel = get_random_channel ();
> >
> >          self->priv->activation_started_ids = g_hash_table_new
> >  (g_direct_hash,
> >  g_direct_equal);
> >  @@ -1718,7 +1721,10 @@
> >                  nm_device_set_active_link (NM_DEVICE (self), FALSE);
> >                  if (reinit_state) {
> >                          self->priv->step = self->priv->default_first_step;
> >  -                       self->priv->channel = get_random_channel ();
> >  +                       if (self->priv->default_first_step ==
> >  MESH_S4_P2P_MESH)
> >  +                               self->priv->channel = 1;
> >  +                       else
> >  +                               self->priv->channel = get_random_channel
> >  ();
> >                          self->priv->chans_tried = 0;
> >                          self->priv->channel_locked = FALSE;
> >                  }
> >  @@ -1754,7 +1760,10 @@
> >                          self->priv->channel =
> >  nm_act_request_get_mesh_channel (req);
> >                          self->priv->channel_locked = TRUE;
> >                  } else {
> >  -                       self->priv->channel = get_random_channel ();
> >  +                       if (self->priv->default_first_step ==
> >  MESH_S4_P2P_MESH)
> >  +                               self->priv->channel = 1;
> >  +                       else
> >  +                               self->priv->channel = get_random_channel
> >  ();
> >                  }
> >          }
> >  ```
> >
> > --
> > Ticket URL: <https://dev.laptop.org/ticket/3593>
> > One Laptop Per Child <https://dev.laptop.org>
> > OLPC bug tracking system
> >
> 
>