[U-Boot] [RFC PATCH v2 0/5] Initial IPv6 support

Chris Packham
2013-01-20T09:44:39Z

On 01/18/2013 11:44 PM, Wolfgang Denk wrote:
> Dear Chris,
>
> In message <50F91851.5050003@gmail.com> you wrote:
>>
>> Good question. Basically we have some out of tree code that implements a
>> basic IPv6 stack. I'm drip feeding the code in pieces to avoid just
>> dumping it on people and because the current code wouldn't meet u-boot's
>> standards.
>
> Can you please go into abit more detail which exact services this
> implements, and how?

TFTP over IPv6 as well as PING6. Our use case is just static address
configuration but using link-local addresses should be doable. I was
thinking it wouldn't be to hard to implement something to generate a
global IPv6 address based on the eui-64 of the device.

> Last time I checked (about 2 years ago) there was no officially
> agreed-on standard for example how network booting should be done in
> IPv6.
>
> There used to be a document how TFTP could handle IPv6 addresses at
> http://datatracker.ietf.org/idtracker/draft-evans-tftp-address-options/comment/50586/
> but this apears to be gone now. The proposal was rejected by then,
> and the comments ("I do recommend the transition to a better
> transport protocol.") sounded as if the IETF would like to abandon
> TFTp under IPv6.

For TFTP it's just a matter of which addresses the server binds to, and
whether the CLI accepts IPv6 addresses. I think we had a patch for
tftp-hpa floating around which was only a few lines. I'm not sure it's
even needed these days.

> I found links for DHCPv6, for example
> http://tools.ietf.org/html/draft-ietf-dhc-dhcpv6-opt-netboot-00
> but no read standard for a bootstrap protocol. Some documents
> indicated it might be based on iSCSI - but that would be quite
> complex; see
> http://tools.ietf.org/html/rfc4173
> http://tools.ietf.org/agenda/72/slides/dhc-12.pdf

DHCPv6 has come along way. At least in terms of address assignment and
interop with other IPv6 auto-configuration mechanisms. I'm not sure
about the bootstrap side of things though.

> So what exactly are you targeting for?

A fairly narrow use-case initially - TFTP with a statically configured
IPv6 address.

At $dayjob we have just added DHCPv6 to our Linux based switches (based
on ISC dhcpd). I wasn't personally involved but it's something we might
be able to help with if there was demand.

>> Putting my IPv6 promoter hat on I hope that it won't stay dead for long :)
>
> Thanks, appreciated!
>
>> Personally I'm happy to have a long running series and periodically send
>> updates to the list. I have a repository on github[1] which has an ipv6
>> branch collecting my changes if anyone wants to pull it down for their
>> own testing. If we want to apply some of the simple stuff early that's
>> fine by me.
>
> I see no problem with handling this as a branch (for example in the
> u-boot-net or u-boot-testing repositories). This should probably be
> decided by Joe Hershberger, though.
>
> Best regards,
>
> Wolfgang Denk
>