ipv6 scope id support

ipv6 scope id support

[orc]

Hi list!
Great to see major changes towards dns code cleanup and rewrite! Here another one:
As I understand, this is a feature when you can specify destination link-local address and from which interface packets are sent. The address and interface are both specified, being separated by '%' (for example, ff02::1%eth0)
I've grepped into glibc sources and found that this step is performed somewhere in dns resolver.

Does musl support this? My current attempt to use it failed.

Re: ipv6 scope id support

[Rich Felker]

On Mon, Jun 09, 2014 at 10:35:39PM +0800, orc wrote:
> Hi list!
> Great to see major changes towards dns code cleanup and rewrite! Here another one:
> As I understand, this is a feature when you can specify destination link-local address and from which interface packets are sent. The address and interface are both specified, being separated by '%' (for example, ff02::1%eth0)
> I've grepped into glibc sources and found that this step is performed somewhere in dns resolver.
> 
> Does musl support this? My current attempt to use it failed.

Can you explain what you did that failed? getaddrinfo should always
accept %nnnn (numeric scope_id) following a numeric address string,
and accepts %ifname if the address has link-local scope (as determined
by IN6_IS_ADDR_LINKLOCAL || IN6_IS_ADDR_MC_LINKLOCAL). Likewise,
getnameinfo will reverse the scope_id to an interface name only fork
link-local addresses, and the reversal can be inhibited with the
NI_NUMERICSCOPE flag.

For non-numeric addresses, scope_id is not parsed at all, but entries
in /etc/hosts can have a scope_id attached to them.

If any of this logic seems incorrect to you, please explain what you
think should be changed.

Rich

Re: ipv6 scope id support

[orc]

10 июня 2014 г. 2:53:37 KRAT, Rich Felker <dalias@libc.org> пишет:
>On Mon, Jun 09, 2014 at 10:35:39PM +0800, orc wrote:
>> Hi list!
>> Great to see major changes towards dns code cleanup and rewrite! Here
>another one:
>> As I understand, this is a feature when you can specify destination
>link-local address and from which interface packets are sent. The
>address and interface are both specified, being separated by '%' (for
>example, ff02::1%eth0)
>> I've grepped into glibc sources and found that this step is performed
>somewhere in dns resolver.
>> 
>> Does musl support this? My current attempt to use it failed.
>
>Can you explain what you did that failed? getaddrinfo should always
>accept %nnnn (numeric scope_id) following a numeric address string,
>and accepts %ifname if the address has link-local scope (as determined
>by IN6_IS_ADDR_LINKLOCAL || IN6_IS_ADDR_MC_LINKLOCAL). Likewise,
>getnameinfo will reverse the scope_id to an interface name only fork
>link-local addresses, and the reversal can be inhibited with the
>NI_NUMERICSCOPE flag.
>
>For non-numeric addresses, scope_id is not parsed at all, but entries
>in /etc/hosts can have a scope_id attached to them.
>
>If any of this logic seems incorrect to you, please explain what you
>think should be changed.

Oh, I am sorry, false alert. I was using 1.0.0 at that time. It lacks this.
And the dns bug will motivate me to upgrade :-)

>
>Rich