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

[Julian H. Stacey]

Brian Somers wrote:
> 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.

Tested. It Works. Thanks !
I tested the patch on PPP running under both kernels IPV4+6 & V4only
just to be sure, it works on both, & allows me to type dial & down
(all I tried or wanted.)

Output With patch:
------------------------
strings /boot/kernel/kernel | grep ___ | grep INET
___options INET
___options INET6
sockstat -l
USER     COMMAND    PID   FD PROTO  LOCAL ADDRESS         FOREIGN ADDRESS      
root     ppp        939   9  tcp46  *:12345               *:*
------------------------
strings /boot/kernel/kernel | grep ___ | grep INET
___options INET
___# options INET6
sockstat -l
USER     COMMAND    PID   FD PROTO  LOCAL ADDRESS         FOREIGN ADDRESS      
root     ppp        931   9  tcp4   *:12345               *:*
------------------------
Old V4+6 Kernel pre patch:
 USER     COMMAND    PID   FD PROTO  LOCAL ADDRESS         FOREIGN ADDRESS
 root     ppp        1020  9  tcp6   *:12345               *:*

I hope it's commited.  (Dont't know if a 2nd tester is needed to verify ?)
Thanks Hajimu :-)
Julian
-- 
Julian Stacey.  BSD Unix C Net Consultancy, Munich/Muenchen  http://berklix.com
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