From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Tue, 13 May 2008 17:50:55 +0000
Subject: Re: [RFC] [DCCP]: Deprecate SOCK_DCCP in favour of SOCK_DGRAM
Message-Id: <20080513175055.GI15306@ghostprotocols.net>
List-Id: <dccp.vger.kernel.org>
References: <20080513072853.GB4514@gerrit.erg.abdn.ac.uk>
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To: dccp@vger.kernel.org

Em Tue, May 13, 2008 at 08:37:38PM +0300, R=E9mi Denis-Courmont escreveu:
> Le Tuesday 13 May 2008 20:03:25 Gerrit Renker, vous avez =E9crit=A0:
> > Using work-arounds is brittle and frustrating when the API behaviour
> > suddenly changes. My experience of using such a wrapper was:
> >
> >  * it passed UDP(-Lite), TCP through without changing the socket type;
> >  * when passed DCCP, it set the socket type to 0, to avoid `ai_socktype
> >    not supported' getaddrinfo error;
>=20
> >  * this used to work fine until about January, when something in the
> >    lookup machinery for dual-stack hosts changed:
> >    - before, AF_UNSPEC + ai_socktype=3D0 put IPv6 first into the result=
 list,
> >    - now the the result order is reversed (IPv4 sockets are returned fi=
rst)
>=20
> You're probably using a recent libc that applies RFC3484 _properly_. If y=
ou=20
> still want IPv6 first, no matter what addresses the host has, I think the=
=20
> AI_PASSIVE flag should do the trick. Then again, working around RFC3484=20
> policy is _not_ a good idea.
>=20
> As far as I am concerned, for DCCP, I (meaning VLC) currently use SOCK_ST=
REAM,=20
> and overrides the socktype and protocol fields in the socket() call=20
> manually - so I don't get a TCP socjet.
>=20
> In any case, getaddrinfo() should be patched to
> 1/ accept ai_socktype =3D SOCK_DCCP and ai_protocol =3D IPPROTO_DCCP,
> 2/ accept ai_socktype =3D SOCK_DCCP and ai_protocol =3D 0,
>    and set ai_protocol to IPPROTO_DCCP in the results,
> 3/ (perhaps?) accept ai_protocol =3D IPPROTO_DCCP and ai_socktype =3D 0,
>    and set ai_socktype to SOCK_DCCP in the results.
>=20
> Similarly:
> 1/ accept ai_socktype =3D SOCK_DGRAM and ai_protocol =3D IPPROTO_UDPLITE,
> 2/ (intentionally omitted - keep normal UDP non-Lite behavior)
> 3/ (perhaps?) accept ai_protocol =3D IPPROTO_UDPLITE and ai_socktype =3D =
0,
>    and set ai_socktype to SOCK_DGRAM in the results.
>=20
> Voil=E0. Best to check this with Ulrich Drepper, no?

Cest bon! Agreed. Ulrich?

- Arnaldo