From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonas Rebmann Subject: Re: [GSoC] Introduction + question about dmd Date: Thu, 5 Mar 2015 14:44:13 +0100 Message-ID: References: <87mw3ryay0.fsf@gnu.org> Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=001a11349e3665933805108ac348 Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:44982) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YTW4V-0003AG-VY for guix-devel@gnu.org; Thu, 05 Mar 2015 08:44:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YTW4U-0003mj-H2 for guix-devel@gnu.org; Thu, 05 Mar 2015 08:44:15 -0500 Received: from mail-la0-x236.google.com ([2a00:1450:4010:c03::236]:34218) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YTW4U-0003mL-4c for guix-devel@gnu.org; Thu, 05 Mar 2015 08:44:14 -0500 Received: by labhs14 with SMTP id hs14so51421822lab.1 for ; Thu, 05 Mar 2015 05:44:13 -0800 (PST) In-Reply-To: <87mw3ryay0.fsf@gnu.org> List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Cc: guix-devel@gnu.org --001a11349e3665933805108ac348 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi, I contacted Ludo about the DHCP client just before I noticed this conversation. I'm interested in making it my gsoc project as well. I'm an undergraduate in computer science in Germany, I'm a bit into free software and I'm especially interested in making my gsoc for the gnu project. Would it be possible to team up on this project? Other project ideas for guix/dmd are very welcome. I'll be waiting for Ludovics reply and see what other project ideas might be interesting for me. Kind regards, Jonas 2015-03-05 11:51 GMT+01:00 Ludovic Court=C3=A8s : > Hello! > > Rohan Prinja skribis: > > > The project I'm interested in working on for GNU GSoC this year is to > > implement a DHCP client library in Guile. The end result, as I discusse= d > > with Ludovic, would be a package installable via Guix. This would make > > available a command roughly equivalent to ISC's dhclient. The library > > should also implement a service that dmd can run. > > Specifically, the library=E2=80=99s functionality should be available in = a way > that makes it easy to integrate in some event loop. > > > Things I've done so far - read the dmd manual, started learning Guile > (I've > > programmed in Racket before, but not Guile), reading up on the DHCP > > protocol, and started looking at ISC's implementation of dhclient (I us= ed > > the one obtained by apt-get source isc-dhcp-client). > > (Alternately, you can get it with =E2=80=98guix build -S isc-dhclient=E2= =80=99. ;-)) > > This is a good start. You might want to look at > more than at the actual > implementation. > > > @Ludovic: continuing our discussion - could you please explain what you > > mean by the dmd event loop? I searched in the manual as well the dmd-0.= 2 > > source but couldn't find any reference to it. Is this something planned > to > > be added to dmd? How will it look like? > > It=E2=80=99s something planned. Basically dmd has to react to various ev= ents; > currently, the only events that happen in practice are SIGCHLD, > connections made by the client programs (=E2=80=98deco=E2=80=99, =E2=80= =98reboot=E2=80=99, etc.), and > commands sent on open connections by these clients. > > Currently, in lieu of an full-blown even loop, there=E2=80=99s just this = naive > loop in the (dmd) module: > > (let next-command () > (match (accept sock) > ((command-source . client-address) > (process-connection command-source)) > (_ #f)) > (next-command)) > > That doesn=E2=80=99t scale well and isn=E2=80=99t safe though, because a = client could > wait forever and thus lead dmd to wait forever as well (although that=E2= =80=99s > slightly beyond the adversary model we would think of.) > > More importantly, we would like dmd to be able to handle other kinds of > events. For instance, I would like it to run a =E2=80=9CREPL server=E2= =80=9D (info > "(guile) REPL Servers"); that means it will also have to check for > events occurring on the REPL server socket. > > Other types of events could include network reconfigurations (which > could be detected via a PF_NETLINK/NETLINK_ROUTE socket), device > additions/removal, events related to the DHCP client process, etc. > > To be able to handle these events, dmd needs a usual event loop. It > doesn=E2=80=99t have it yet, but that=E2=80=99s something I=E2=80=99m pla= nning to add (I say =E2=80=9CI=E2=80=9D > but anyone reading this message is welcome to help ;-)). > > Does it clarify things a bit? > > Thanks, > Ludo=E2=80=99. > > --001a11349e3665933805108ac348 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Hi,
I contacted Ludo about the DHCP client just before I no= ticed this conversation. I'm interested in making it my gsoc project as= well.
I'm an undergra= duate in computer science in Germany, I'm a bit into free software and = I'm especially interested in making my gsoc for the gnu project.
<= div style=3D"font-size:12.8000001907349px">Would it be possible to team up = on this project?
Other pro= ject ideas for guix/dmd are very welcome.
I'll be waiting for Ludovics reply and see what other p= roject ideas might be interesting for me.

K= ind regards,
Jonas

2015-03-05 11= :51 GMT+01:00 Ludovic Court=C3=A8s <ludo@gnu.org>:
Hello!

Rohan Prinja <rohan.prinja@gma= il.com> skribis:

> The project I'm interested in working on for GNU GSoC this year is= to
> implement a DHCP client library in Guile. The end result, as I discuss= ed
> with Ludovic, would be a package installable via Guix. This would make=
> available a command roughly equivalent to ISC's dhclient. The libr= ary
> should also implement a service that dmd can run.

Specifically, the library=E2=80=99s functionality should be available in a = way
that makes it easy to integrate in some event loop.

> Things I've done so far - read the dmd manual, started learning Gu= ile (I've
> programmed in Racket before, but not Guile), reading up on the DHCP > protocol, and started looking at ISC's implementation of dhclient = (I used
> the one obtained by apt-get source isc-dhcp-client).

(Alternately, you can get it with =E2=80=98guix build -S isc-dhclient=E2=80= =99.=C2=A0 ;-))

This is a good start.=C2=A0 You might want to look at
<http= s://www.ietf.org/rfc/rfc2131.txt> more than at the actual
implementation.

> @Ludovic: continuing our discussion - could you please explain what yo= u
> mean by the dmd event loop? I searched in the manual as well the dmd-0= .2
> source but couldn't find any reference to it. Is this something pl= anned to
> be added to dmd? How will it look like?

It=E2=80=99s something planned.=C2=A0 Basically dmd has to react to various= events;
currently, the only events that happen in practice are SIGCHLD,
connections made by the client programs (=E2=80=98deco=E2=80=99, =E2=80=98r= eboot=E2=80=99, etc.), and
commands sent on open connections by these clients.

Currently, in lieu of an full-blown even loop, there=E2=80=99s just this na= ive
loop in the (dmd) module:

=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (let next-command ()
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (match (accept sock)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 ((command-source . client-= address)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0(process-connection = command-source))
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (_ #f))
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (next-command))

That doesn=E2=80=99t scale well and isn=E2=80=99t safe though, because a cl= ient could
wait forever and thus lead dmd to wait forever as well (although that=E2=80= =99s
slightly beyond the adversary model we would think of.)

More importantly, we would like dmd to be able to handle other kinds of
events.=C2=A0 For instance, I would like it to run a =E2=80=9CREPL server= =E2=80=9D (info
"(guile) REPL Servers"); that means it will also have to check fo= r
events occurring on the REPL server socket.

Other types of events could include network reconfigurations (which
could be detected via a PF_NETLINK/NETLINK_ROUTE socket), device
additions/removal, events related to the DHCP client process, etc.

To be able to handle these events, dmd needs a usual event loop.=C2=A0 It doesn=E2=80=99t have it yet, but that=E2=80=99s something I=E2=80=99m plann= ing to add (I say =E2=80=9CI=E2=80=9D
but anyone reading this message is welcome to help ;-)).

Does it clarify things a bit?

Thanks,
Ludo=E2=80=99.


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