Re: [PATCH 01/11] net: Add l_net_subnet_matches

Hi Andrew,

> I put the following comment in one of the patches:
> 
> +        * TODO: check if we have a prefix route covering the IP,
> +        * l_dhcp6_client doesn't guarantee that the received IP is in
> +        * on of the subnets marked as on-link in the RA.
> 

You keep repeating this, but I still don't believe this is true.  You could have 
RA gateway address being link-local, or subnet C.  The prefix info in the RA 
could be subnet B and the DHCPv6 address obtained could be in subnet A with no 
overlap.  Why would you want to? Who knows ;)

The only 'requirement' is that the gateway is routable.  If it isn't, then 
obviously no traffic can get outside.

So I would simply drop this TODO, and any hope of doing any sort of validation. 
  Let the kernel do this.

> That's a different discussion.  We might want to warn or directly
> return an error from the D-Bus .Connect call if the connection is
> unusable, rather than ignore it and make the user discover it the hard
> way.  You could argue that it's usable for local traffic though.
> 

Let the higher layers deal with it.  If they need internet connectivity, then 
services like connman already implement these types of checks.

>> If there is no gateway and the DNS address is not 'onlink', what 'implicit'
>> route can we add that would make any sense?
> 
> You could add a direct route for that ip, assume it's 'onlink'.  But

Yeah, no :)

> it's really an error situation and should rather be treated that way
> IMHO.

Sure, but I'd still let the higher levels deal with it.

Regards,
-Denis