Re: [lwip-devel] IPv6 design considerations

[Kieran Mansley]

On Tue, 2010-11-09 at 08:04 +0100, Simon Goldschmidt wrote:
> If that's enough that's fine. However, I would have thought we would
> need a new ip_addr_t-like struct that contains both the union and a
> type information (i.e. "isipv6"). For example, after creating a new
> tcp pcb, it would be nice to just pass in the address and connect to
> whatever the address points to. Otherwise, you would need different
> connect functions for v4 and v6 (as the address then has a different
> type).

I agree that duplicating code for the two different address families
would be best avoided, so adding type information will be essential.

> The downside is that the size of ipv4 addresses increases (which is
> quite optimal with 4 bytes, currently).

Is that really a significant downside?  ip_addr_t is already passed
around as a pointer rather than a value so I would not expect the effect
of the difference in size of adding the type field to be significant.
Perhaps I've missed something about ip_addr_t being 4 bytes?

Kieran