Re: IPv6 mass_dns and nsock_connect_udp

[jah <jah () zadkiel plus com>]

On 03/12/2008 01:06, Kris Katterjohn wrote:
> On 12/02/2008 06:28 PM, jah wrote:
> > Hi folks,
>
>
> Hey jah,
>
> > I'm making some progress with a little project to allow mass_rdns to do
> > lookups for IPv6 addresses (async code rather than the system resolver)
> > and to connect to an IPv6 socket on dns servers - I'm using MS Visual
> > C++ EE.
>
> > I've changed a member of the struct dns_server_s from sockaddr_in to
> > sockaddr_storage and hit a snag after connect_dns_servers() calls
> > nsock_connect_udp().
>
> > Previously, connect_dns_servers passed a reference to a dns_server_s
> > sockaddr_in casted to a pointer to a sockaddr along with sizeof(struct
> > sockaddr) which are defined as saddr and sslen respectively in
> > nsock_connect_udp.
> > saddr is then casted to pointer to a sockaddr_storage, but sslen remains
> > unchanged:
>
>
> Instead of passing "sizeof(struct sockaddr)" for sslen, you should
> pass in the
> size of the struct you're using.  So pass in "sizeof(struct
> sockaddr_in)" for
> IPv4 or "sizeof(struct sockaddr_in6)" for IPv6.  The current use of
> sockaddr{}
> works because both it and sockaddr_in{} should always be the same size
> (look
> at the sin_zero field of the latter).
Thanks for that Guys, most helpful.

I think what I need to do is add an addr_len member to dns_server_s
which will be set to the correct size by resolve() in tcpip.cc and I can
then pass that to nsock_connect_udp().
So far I've seen sslen to be 10 for an IPv4 address and 28 (not 128!)
for an IPv6 one - this seems sane and it certainly works:

mass_rdns: Using DNS server 2001:a88:0:fffa::1
mass_rdns: OK MATCHED <2001:a88:0:fffa::1> to <ns0.ipv6.claradns.net>
Completed Parallel DNS resolution of 1 host. at 02:16, 0.03s elapsed

Thanks again.

jah







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