[ds6-devel] no more objections

[Chris Leishman]

On Tuesday, December 31, 2002, at 12:27 AM, Mauro Tortonesi wrote:

>
> chris,
>
> 	i was thinking to the double binding stuff we talked about
> yesterday. i think the best behaviour is:
>
> - always reorder the res struct to have ipv6 sockaddrs first
> - inside the for loop:
>   1) check that getaddrinfo does not return ipv4-mapped addresses
>   2) skip if family != PF_INET and family != PF_INET6
>   3) use IPV6_V6ONLY if the system supports it
>   4) warn if cannot bind to ptr->ai_addr
>
> we can't do much more than this without complicating too much the 
> design
> of nc6 (e.g. including checks for double binding and/or to discover if 
> a
> particular addressed is already bound to another process).
>
> so, i have no more objections to remove the functions is_ipv6_enabled 
> and
> is_double_binding_sane. i will do this tomorrow, if you agree.


I'm not sure what the point of 1) and 2) is.  Do we really care if 
getaddrinfo returns IPv4 mapped addresses?  And do we really need to 
limit it to only PF_INET and PF_INET6 - there's no really need to loose 
the AF independence of the code when all we really need to limit is the 
sock types that we can support.

Did you see the algorithm I posted?


On systems where IPV6_V6ONLY is not defined or the setsockopt with it 
fails:
	- Keep track of whether an IPv6 socket has been bound.
	- If a bind to IPv4 fails with EADDRINUSE and an IPv6 socket
	  has been bound, then just ignore the error.

I would probably extend this to only tracking IPv6 binds to 
IN6_ADDR_ANY, and only ignoring errors from IPv4 binds to IN_ADDR_ANY.


What do you think of this?

Regards,
Chris