Re: [PATCH BlueZ] mesh: Ignore beacons with IVU if IV already updated

["Gix, Brian" <brian.gix@intel.com>]

Hi Rafał,

On Tue, 2020-04-07 at 11:32 +0200, Rafał Gajda wrote:
> When daemon receives beacon with IV=n+1, IVU=False it will                                          
> start sending messages with new IV and set sequence to 0.                                           
> However if daemon receives another beacon with IV=n+1, IVU=True it                                  
> will go back to sending messages with old IV=n (IVU will be set to                                  
> True).                                                                                              
> Because sequence number has been reset those messages will be dropped                               
> by replay protection and node will lose communication.                                              
>                                                                                                     
> Once IV is updated daemon should not go back to using the old value.                                
>                                                                                                     
> This patch adds beacon rejection if IV has already been updated.   
> 
> ---
>  mesh/net.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/mesh/net.c b/mesh/net.c
> index 9a56d2ee8..2f51a5ade 100644
> --- a/mesh/net.c
> +++ b/mesh/net.c
> @@ -2717,6 +2717,12 @@ static void update_iv_ivu_state(struct mesh_net *net, uint32_t iv_index,
>  			return;
>  		}
>  
> +		/* Ignore beacons with IVU if IV already updated */
> +		if (iv_index == net->iv_index) {
> +			l_info("iv already updated");
> +			return;
> +		}
> +

I see the bug you are fixing, and agree with the fix.

I have spun a v2 of this patch I would like to to OK:

1. I have eliminated the l_info output, because with a lot of nodes, this sends out a burst of "iv already
updated" strings each time this occurs (which seems to be a lot).

2. I added the equivilent check to the IV_UPD_INIT state, since this could just as easily happen on restart,
where the first beacon a daemon hears has the old IVU state as well...

I will await your OK before applying.

>  		if (!net->iv_update) {
>  			l_info("iv_upd_state = IV_UPD_UPDATING");
>  			net->iv_upd_state = IV_UPD_UPDATING;