ppp command port does not listens on ipv4 unless no INET6 in kernel

[Brian Somers]

On Sun, 17 Sep 2006 20:10:47 +0900 Hajimu UMEMOTO <ume at freebsd.org> wrote:
> Hi,
> 
> >>>>> On Thu, 14 Sep 2006 15:44:18 +0200 (CEST)
> >>>>> "Julian Stacey" <jhs at berklix.org> said:
> 
> jhs> I'm not clear if this is a bug or a config error:
> jhs>         It seems though my /usr/sbin/ppp was moving traffic
> jhs>         to & from internet, it was only listening for commands
> jhs>         (not data) on ipv6, not ipv4, thus I could not type commands
> jhs>         like dial & drop, unless instead of running ppp -auto
> jhs>         instead I invoked ppp manually in foreground on localhost.
> 
> As far as I read the source of ppp(8), it only listen on an IPv6, and
> expects to listen on an IPv4 through an IPv4-mapped IPv6 address.
> However, an IPv4-mapped IPv6 address feature is disabled by default.
> ppp(8) should be rewritten to listen on both an IPv4 and an IPv6.
> But, it is slightly complex.  So, I made a patch to enable an
> IPv4-mapped IPv6 address only for the socket that ppp(8) is listening
> on.
> I have no environment for testing this.  Could you try this patch?
> 
> Index: usr.sbin/ppp/server.c
> diff -u -p usr.sbin/ppp/server.c.orig usr.sbin/ppp/server.c
> --- usr.sbin/ppp/server.c.orig	Sun Sep  5 10:46:52 2004
> +++ usr.sbin/ppp/server.c	Sun Sep 17 19:54:43 2006
> @@ -346,6 +346,13 @@ server_TcpOpen(struct bundle *bundle, u_
>      goto failed;
>    }
>  
> +#ifndef NOINET6
> +  if (probe.ipv6_available) {
> +    int off = 0;
> +    setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&off, sizeof(off));
> +  }
> +#endif
> +
>    setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &s, sizeof s);
>    if (bind(s, (struct sockaddr *)&ss, sz) < 0) {
>      log_Printf(LogWARN, "Tcp: bind: %s\n", strerror(errno));
> 
> 
> Sincerely,

AFAIR I had trouble getting that code to work and was advised at
the time that I'd just get the mapped port for free.  I haven't
been using IPv6 on production machines for some time, so I haven't
seen the problem :(

It'd be great if you'd commit the patch if Julian says it works
ok for him.

Cheers.

-- 
Brian Somers                                          <brian at Awfulhak.org>
Don't _EVER_ lose your sense of humour !               <brian at FreeBSD.org>