Date: Thu, 3 Jul 2003 15:00:34 -0700 (PDT) From: Doug Ambrisko <ambrisko@ambrisko.com> To: Julian Elischer <julian@elischer.org> Cc: freebsd-net@freebsd.org Subject: Re: Suggesting for fixing VLAN bridging the right way Message-ID: <200307032200.h63M0YcL088406@www.ambrisko.com> In-Reply-To: <Pine.BSF.4.21.0307031444120.78043-100000@InterJet.elischer.org>
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Julian Elischer writes:
| how does netgraph bridging do?
I'm actually using netgraph bridging sort-of, kind-of. Since I don't
care about loops and I'm only connecting to interfaces together
I just doing
ngctl connect vlan0: rl0: lower lower
with the setpromisc, setautosrc etc. Luigi's bridging had the
same issue.
This is actually a simple test case. What I'm doing it actually more
complicated for our product VLAN testing. With this hack now my test
stuff works (I do a IP re-map to do a poor man's virtualization of the
network stack ... which by the way I tried out the latest virtual
network stuff. It sort-of worked but ran into some bugs and quirks).
So this is a fundamental bug, in which the packets from the NIC
don't make it to the vlan SW layer and things break. I guess
I didn't explain that part well based on some other questions I got.
You also have to set the NIC in promiscous mode as well. Seems like
if you configure a VLAN and modes those things should get enabled
on the base NIC. Granted it could get funky with HW VLAN support.
It strange since I don't ifconfig the NIC but I always have to do
an 'ifconfig <nic> up' to make the VLAN work at all. That's a little
odd.
Also you can see the bug via tcpdumps. You see the packets come in
on the NIC but never make to the vlan iface.
Doug A.
| On Thu, 3 Jul 2003, Doug Ambrisko wrote:
|
| > I'm trying to bridge VLAN traffic to network that doesn't have that VLAN,
| > something like:
| > (vlan network) -> fxp0 -> vlan0 <- FreeBSD bridge -> rl0 (no tag)
| >
| > Both of the networks are the same except one side is tagged the other
| > has no tag.
| >
| > It works fine in the "no tag" -> "tag" direction. It fails in the
| > "tag" -> "no tag" direction since ether_demux we bail out on this
| > check:
| > if (!(BDG_ACTIVE(ifp))) {
| > /*
| > * Discard packet if upper layers shouldn't see it because it
| > * was unicast to a different Ethernet address. If the driver
| > * is working properly, then this situation can only happen
| > * when the interface is in promiscuous mode.
| > */
| > if ((ifp->if_flags & IFF_PROMISC) != 0
| > && (eh->ether_dhost[0] & 1) == 0
| > && bcmp(eh->ether_dhost,
| > IFP2AC(ifp)->ac_enaddr, ETHER_ADDR_LEN) != 0
| > && (ifp->if_flags & IFF_PPROMISC) == 0) {
| > m_freem(m);
| > return;
| > }
| > }
| >
| > since it doesn't consider VLAN tagged packets coming in the headers
| > won't match this paradigm so the packets get through out. I did a quick
| > hack and changed it to:
| > if (!(BDG_ACTIVE(ifp))) {
| > /*
| > * Discard packet if upper layers shouldn't see it because it
| > * was unicast to a different Ethernet address. If the driver
| > * is working properly, then this situation can only happen
| > * when the interface is in promiscuous mode.
| > */
| > if ((ifp->if_flags & IFF_PROMISC) != 0
| > && (eh->ether_dhost[0] & 1) == 0
| > && bcmp(eh->ether_dhost,
| > IFP2AC(ifp)->ac_enaddr, ETHER_ADDR_LEN) != 0
| > && (ifp->if_flags & IFF_PPROMISC) == 0) {
| > /*
| > * Let VLAN packets go to the SW VLAN node needed for
| > * bridging
| > */
| > if (! (vlan_input_p != NULL
| > && ntohs(eh->ether_type) == ETHERTYPE_VLAN )) {
| > m_freem(m);
| > return;
| > }
| > }
| > }
| >
| > That makes it work. I rather doubt this is the right solution.
| >
| > Suggestions greatly appreciated. This issue is in -current and -stable.
| >
| > Thanks,
| >
| > Doug A.
| > _______________________________________________
| > freebsd-net@freebsd.org mailing list
| > http://lists.freebsd.org/mailman/listinfo/freebsd-net
| > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"
| >
|
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