On 23/10/15(Fri) 13:21, David Gwynne wrote:
>
> > On 23 Oct 2015, at 09:00, Reyk Floeter <r...@openbsd.org> wrote:
> >
> > Hi,
> >
> > this diff allows to interconnect routing domains.
> >
> > It is very useful to route traffic from one routing domain to another,
> > without using the pf "rtable" hack (tested in production for a long
> > time).
> >
> > eg.,
> > # ifconfig vether0 10.0.1.1/24
> > # ifconfig vether1 rdomain 1 10.0.1.2/24
> > # ping 10.1.1.2
> > # route -T 1 add default 10.0.1.1
> > # ifconfig bridge0 add vether0 add em0
> >
> > for hacking/testing, you can do thing like:
> > # dhcpd vether0
> > # dhclient vether1
> >
> > It has been discussed in much detail if this is possible with
> > bridge(4). It is not. The bridge is not designed for it and explain
> > on request.
>
> the diff implements a crossover option, but the example above doesnt use
> them. does that mean you can use a bridge to build crossovers without the
> extra code, or the example is wrong?
As said yesterday an alternative would be to use the bridge(4) as below:
Index: net/if_bridge.c
===================================================================
RCS file: /cvs/src/sys/net/if_bridge.c,v
retrieving revision 1.268
diff -u -p -r1.268 if_bridge.c
--- net/if_bridge.c 12 Oct 2015 10:03:25 -0000 1.268
+++ net/if_bridge.c 23 Oct 2015 11:52:13 -0000
@@ -1218,10 +1218,12 @@ bridgeintr_frame(struct bridge_softc *sc
if (m == NULL)
return;
/*
- * If the packet is a multicast or broadcast OR if we don't
- * know any better, forward it to all interfaces.
+ * If the packet is a multicast/broadcast, if we don't know
+ * any better or if the destination is in a different routing
+ * domain, forward it to all interfaces.
*/
- if ((m->m_flags & (M_BCAST | M_MCAST)) || dst_if == NULL) {
+ if ((m->m_flags & (M_BCAST | M_MCAST)) || dst_if == NULL ||
+ (dst_if->if_rdomain != src_if->if_rdomain)) {
sc->sc_if.if_imcasts++;
bridge_broadcast(sc, src_if, &eh, m);
return;
