[getdns-api] link-local recursive name server addresses

[Willem Toorop]

Hi Tony, Hi Paul,

Paul, I have an API text change proposal below.

Support for ipv6 link-local addresses is in the development branch
(called master ;) of our implementation:
https://github.com/getdnsapi/getdns

Link-local addresses with scope_id are read in correctly from
/etc/resolv.conf .  Those scope_id's may also be provided (by name or
number) with getdns_context_set_upstream_recursive_servers, with the
"scope_id" name (a bindata) in the stub resolver dict.

I propose to insert a line just after the first two lines in the last
paragraph of section 8.7, like so:

	"The list of dicts define where a stub resolver will send queries. Each
dict contains at least two names: address_type (whose value is a
bindata; it is currently either "IPv4" or "IPv6") and address_data
(whose value is a bindata).  For IPv6 link-local addresses, a scope_id
name (a bindata) can be provided."

OK?

-- Willem

Op 01-07-14 om 19:43 schreef Tony Finch:
> Thomas Schäfer reported an interesting bug on the ipv6-ops list:
> http://lists.cluenet.de/pipermail/ipv6-ops/2014-July/010032.html
> 
> The problem occurs when /etc/resolv.conf contains a link-local nameserver
> address, which necessarily includes a scope so that the address is
> associated with the correct interface.
> 
> Some stub resolver libraries fail to parse the scope - usually they ignore
> the scope rather than failing, but this results in the wrong interface
> index in the eventual sockaddr, so the resolver ends up unable to talk to
> its server.
> 
> The interestingly awkward thing about this bug is that it implies that you
> cannot use a simple IPv6 address (e.g. AAAA RDATA) to represent a stub
> resolver's name server addresses. Unfortunately the getdns API assumes
> that you can; to fix this it needs to learn about scoped addresses.
> 
> Tony.
> 
> 
> 
> _______________________________________________
> getdns-api mailing list
> getdns-api at vpnc.org
> 

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