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

[Denis Kenzior <denkenz at gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 1406 bytes --]

Hi Andrew,

> With IPv6 Router Advertisements you can have knowledge of multiple
> on-link prefixes.  The gateway needs to match one of them in exactly
> the same way as with IPv4.

But netconfig is not doing this matching? The kernel is?  icmp6 simply puts in 
the default gateway info and the prefix routes into the routing table.  I don't 
think it is 'our problem' if the prefixes and route info from the RA results in 
the RA address not being routable.


> Well, if that address you're trying to validate (e.g. let's say your
> DNS IP) is on-link, which you'd find out from the RA, then you don't
> need to add anything to the routing table because your RA handler will
> already have added that route.  If it's not and there's no default
> router, then either it's an error or you might want to implicitly add
> a route for it.

If there is no gateway and the DNS address is not 'onlink', what 'implicit' 
route can we add that would make any sense?  Isn't the address simply unreachable?

Why would we be 'validating' the DNS address in the first place?  How would we 
validate it?

> 
> But the way you'd find out whether given IP is on-link is by calling
> l_net_subnet_matches for each prefix.  Their lengths vary from 0 to
> 128 like the RFC says.

Anyhow, just rename this function l_net_prefix_matches, since that is what you 
really intend.

Regards,
-Denis