[U-Boot] [RFC PATCH 6/8] net: TFTP over IPv6

[Joe Hershberger]

Hi Chris,

On Wed, Nov 4, 2015 at 2:42 AM, Chris Packham <judge.packham at gmail.com> wrote:
> On Wed, Nov 4, 2015 at 8:43 AM, Joe Hershberger
> <joe.hershberger at gmail.com> wrote:
>> Hi Chris,
>>
>> On Tue, Nov 3, 2015 at 4:15 AM, Chris Packham <judge.packham at gmail.com> wrote:
>>> On Tue, Nov 3, 2015 at 9:43 AM, Joe Hershberger
>>> <joe.hershberger at gmail.com> wrote:
>>>> Hi Chris,
>>>>
>>>> On Mon, Oct 12, 2015 at 2:43 AM, Chris Packham <judge.packham at gmail.com> wrote:
>>>>> Add support for UDP/TFTP over IPv6.
>>>>>
>>>>> Signed-off-by: Chris Packham <judge.packham at gmail.com>
>>>>> ---
>>>>> One problem with the [hostIpAddr:]fileName syntax is that IPv6 addresses
>>>>> contains colons. So tftp_start() would be confused by 'tftpboot6
>>>>> $loadaddr 2001:db8::1:zImage'. It is probably possible to change the
>>>>> parsing to separate the host from the filename by parsing from the end
>>>>> (i.e. use strrchr() instead of strchr()) but then there are error cases
>>>>> that may not be handled correctly (e.g. omitting the filename).
>>>>
>>>> I think we should just change the filename separator for tftp6. How about ','?
>>>>
>>>
>>> The other strategy that is often used is to use square brackets to
>>> separate the address from other data e.g. http://[2001:db8::1]:8080/.
>>> Maybe that is a better (or at least more common) approach.
>>
>> Sounds good to me - I'm all for going with a common approach.
>>
>
> One wrinkle I've just discovered with this suggestion is the command
> line help text. Consider the following
>
>   => help tftpboot
>   Usage:
>   tftpboot [loadAddress] [[hostIPaddr:]bootfilename]
>
> Now the IPv6 version if the above syntax is supported
>   => help tftpboot6
>   Usage:
>   tftpboot6 [loadAddress] [[[hostIP6addr]:]bootfilename]
>
> How do we convey that the address before the bootfilename is optional
> but if it is specified square brackets are required around the
> address. In other words
>
>   tftpboot6 (valid)
>   tftpboot6 zImage (valid)
>   tftpboot6 2001:db8::1:zImage (invalid)
>   tftpboot6 [2001:db8::1]:zImage (valid)
>
> I still like the square bracket syntax and I'm still planning on
> implementing it but I thought I'd raise this now to give people a
> chance to object.

That's unfortunate.

Maybe something like

tftpboot6 [loadAddress] [[\[hostIP6addr\]:]bootfilename]

or

tftpboot6 [loadAddress] [['['hostIP6addr']':]bootfilename]

I don't love either, but does it get the message across?

-Joe