[OpenAFS-devel] N800, Mobile AFS, and changing IP addresses

[Jeffrey Altman]

Simon Wilkinson wrote:
> 
> On 27 Apr 2008, at 01:50, Jason Edgecombe wrote:

>> 2. What should be done when the network comes up, down, or gets a new IP?
> 
> You should generate the new list of interfaces, and then make the 
> AFSOP_ADVISEADDR syscall, setting 'code' to note the fact its a refresh. 
> See afsd_update_addresses for the Darwin version of this code (a 
> non-darwin version would be pretty much the same, but with a different 
> prototype)
> 
> If you're not using Net* restrictions, or rxbind, I think the only thing 
> you really need to do is to reset the list of down servers - so servers 
> that were marked down whilst you were disconnected, or connected to a 
> network which blocked AFS, get marked back up again.

Instead of resetting down servers blindly I recommend performing a probe 
of all VL and File servers to determine their new state.  You know the 
network configuration just changed.  Things that were accessible may no 
longer be and vice versa.  See afs_CheckServer()

>> 3. How can I deal with wifi networks that block AFS?
> 
> Tune the AFS timeouts so that the user get's failure messages more quickly?

Performing the check at the time the network configuration changed will 
ensure that the cache manager knows as soon as possible whether or not 
the desired servers are in fact accessible.   If they are not the cache 
manager can fail requests immediately.

Jeffrey Altman