On Sun, Mar 22, 2009 at 09:04:50PM -0700, Stephen Hemminger wrote: > On Sun, 22 Mar 2009 06:26:20 -0700 > Garry Dolley <gdolley@xxxxxxxxxxxxxxx> wrote: > > > Dear linux-net, > > > > I'm running the stock kernel of Ubuntu Hardy: > > 2.6.27-7-generic #1 SMP Tue Nov 4 19:33:06 UTC 2008 x86_64 GNU/Linux > > > > My eth0 is: > > driver: e1000e > > version: 0.3.3.3-k6 > > firmware-version: 2.1-12 > > bus-info: 0000:04:00.0 > > > > If have several VLANs configured on eth0, such as: > > > > eth0.105 > > eth0.106 > > eth0.107 > > > > When I run tcpdump on each, I can see the traffic for the respective VLAN. > > When I tcpdump eth0, I can see the traffic for *all* the VLANs. > > > > So far so good. > > > > Except, when I look at the traffic for all the VLANs, the VLAN ID is not > > present. Many hours of googling, looking at the e1000e driver code and VLAN > > code, and picking other ppl's brains, has led me to believe that VLAN > > hardware acceleration is stripping the tag from the frame, so I can't actually > > see the VLAN ID. > > > > So my question is, is it possible to turn hwaccel off for this card without > > hacking and recompiling the driver? Or can I get the VLAN ID using some other > > method that I don't know about? > > no, without recompiling driver. Roger that. > > Also, some of code and commit messages I've read seem to indicate even if > > tcpdump could show me the VLAN ID, I wouldn't necessarily get any of this > > traffic unless eth0 is in promisc mode. > > There are patches to libpcap, that teach it how to handle this. > http://www.mail-archive.com/tcpdump-workers@xxxxxxxxxxxxxxxxx/msg03866.html Awesome, thanks for that link. > > My main goal here is to be able to bridge eth0 to another device and ensure > > that that device can see all the tagged traffic that comes in eth0. eth0 is > > plugged into a Cisco switch and is a trunk port. > > > > Any suggestions? > > Find (or patch) a version of tcpdump that knows about PACKET_AUXDATA Roger that. OK, now for some news; I think I solved my problem. VLAN hardware acceleration wasn't the issue; as of kernel 2.6.27, I *can* see all the vlan tags on eth0, but there is a big catch -- eth0 cannot actually participate in any VLANs. That is, if no VLANs have been configured on eth0, I can tcpdump like so: tcpdump -i eth0 vlan and see all the traffic with the tags. But as soon as I do: vconfig add eth0 500 Thereby creating eth0.500, then: tcpdump -i eth0 vlan shows absolutely no traffic. However: tcpdump -i eth0 shows all the traffic, like in my first example, except the packets are all *untagged*. I take it as soon as a VLAN is added to eth0, creating a sub-interface (eth0.500), then only the sub-interfaces "see" traffic (and they are untagged, as expected). The main interface, eth0, no longer sees the VLAN tags, they have been stripped out already (by 8021q module maybe?). -- Garry Dolley ARP Networks, Inc. http://www.arpnetworks.com Data center, VPS, and IP transit solutions (818) 206-0181 Member Los Angeles County REACT, Unit 336 WQGK336 Blog http://scie.nti.st -- To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
