SO_BINDTODEVICE and ipv6

[John Newlin]

On Sat, May 31, 2014 at 9:29 AM, /dev/rob0 <rob0 at gmx.co.uk> wrote:

> On Thu, May 29, 2014 at 07:21:18AM -0700, John Newlin wrote:
> > In socket.c SO_BINDTODEVICE is not used for ipv6.  Is there any
> > reason this isn't used for ipv6?
> >
> > Our system has two interfaces we want to run dhclient on, and
> > this is causing issues as the dhcpv6 Reply is going to the
> > wrong instance of dhclient.  Before I change it, I'd like to
> > know the rationale for disabling it for ipv6.
>
> I admit to being mostly out of my league with this question, however
> in this case I think I have the right answer. :)
>
> DHCPv6, rather than using raw sockets as DHCPv4 did, communicates
> using the IPv6 link-local address.
>
> (I'd appreciate confirmation or correction from someone who knows
> better, thanks.)
>

Pretty sure that's correct.  I have 1 physical interface, and am running on
the untagged and a vlan interface, and I think they have the same link
local address.  I definitely see packets going to the wrong interface.


>
> As for the problem at hand, perhaps you could run a single dhclient
> instance for both interfaces?
>

Is that possible?  I'll have to read the doc again.  :)



>
> > // socket.c  relevant code.
> > #if defined(SO_BINDTODEVICE)
> >         /* Bind this socket to this interface. */
> >         if ((local_family != AF_INET6) && (info->ifp != NULL) &&
> >             setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE,
> >                         (char *)(info -> ifp), sizeof(*(info -> ifp))) <
> 0)
> > {
> >                 log_fatal("setsockopt: SO_BINDTODEVICE: %m");
> >         }
> > #endif
> --
>   http://rob0.nodns4.us/
>   Offlist GMX mail is seen only if "/dev/rob0" is in the Subject:
> _______________________________________________
> dhcp-users mailing list
> dhcp-users at lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.isc.org/pipermail/dhcp-users/attachments/20140531/541f677f/attachment.html>