Re: [Caml-list] IPv6 zone-id

["Raphaël Proust" <raphlalou@gmail.com>]

On Wed, Jul 9, 2014 at 6:35 PM, Vincent B. <vb@luminar.eu.org> wrote:
> The Unix module does not make possible to use IPv6 link-local
> addresses.
>
> This is due to the fact that the "sockaddr" type in Unix is not as
> complete as its C counterpart, especially it lacks zone-id information
> that is required to use such addresses.
>
> Since I needed such features, I started writing a library
> (http://github.com/vbmithr/ocaml-sockopt), unfortunately, given that
> every networking piece of code written in OCaml use the primitives of
> the Unix module, I would have to patch all networking code I want to
> use which is not very convenient.

Is it possible to make a new networking module using Cstruct to manage
sockaddr and such?


>
> So I'm in the process of writing a patch for OCaml and I'm taking the
> approach of extending the sockaddr type like this:
>
> type sockaddr_raw (* a real struct sockaddr *)
>
> type sockaddr =
>   ADDR_UNIX of string
> | ADDR_INET of inet_addr * int
> | ADDR_RAW of sockaddr_raw
>
> And then upgrading all the Unix code that uses type sockaddr.
>
> This approach seems to me the most conservative towards existing
> code. Should I continue in this direction or this design is not the
> optimal one ?

Although very conservative towards the existing codebases, I don't
like this approach for the following reasons.

The same sockaddr can be represented in different ways (which means
that equality becomes non-trivial, and the choice of representation is
non-obvious for programmers).

The Unix module is build as abstractions from the underlying system,
adding a sockaddr_raw defeats that. It becomes abstractionless.


Additionally, is sockaddr_raw completely opaque? what
constructors/destructors are available?



Cheers,
-- 
______________
Raphaël Proust