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

[Walter Bender]

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?

-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
>


-- 
Walter Bender
One Laptop per Child
http://laptop.org