Date:	Mon, 10 Oct 2011 17:05:52 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Michael Tokarev <mjt@....msk.ru>
Cc:	David Lamparter <equinox@...c24.net>, jeffrey.t.kirsher@...el.com,
	netdev <netdev@...r.kernel.org>
Subject: Re: e100 + VLANs?

Le lundi 10 octobre 2011 à 18:57 +0400, Michael Tokarev a écrit :
> 10.10.2011 14:19, David Lamparter wrote:
> > On Sat, Oct 08, 2011 at 11:34:40AM -0700, Jeff Kirsher wrote:
> >> On 10/08/2011 09:24 AM, Eric Dumazet wrote:
> >>> Le samedi 08 octobre 2011 à 14:08 +0400, Michael Tokarev a écrit :
> >>>>> Yesterday I tried to use 802.1Q VLAN tagging with an (oldish)
> >>>>> e100-driven network card, identified by lspci like this:
> >>>>>
> >>>>>  00:12.0 Ethernet controller: Intel Corporation 82557/8/9/0/1 Ethernet Pro 100 (rev 02)
> >>>>>
> >>>>> Just to discover that it does not quite work: packets of
> >>>>> size 1497+ bytes gets lost.
> > [...]
> >>> e100 driver seems VLAN enabled at a first glance.
> >> Eric is correct, that e100 does support VLANs.
> >>
> >> In addition to Eric's suggestion, can you also provide all the output of
> >> lspci -vvv for the network card?
> > 
> > I'm opening the lore box here, but early e100 cards AFAIK have a 
> > hardware limit at 1500 (+18 src/dst/proto) bytes. At least, Juniper's
> > JUNOS does not support full-sized .1Q on their e100 control plane
> > interfaces...
> 
> Thank you all for the suggestions and feedback.
> 
> The card may indeed be quite old, I don't know where it come from and
> when.  Here's lspci -vvv for it:
> 
> 00:12.0 Ethernet controller: Intel Corporation 82557/8/9/0/1 Ethernet Pro 100 (rev 02)
> 	Subsystem: Intel Corporation EtherExpress PRO/100B (TX)
> 	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx-
> 	Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
> 	Latency: 66 (2000ns min, 14000ns max)
> 	Interrupt: pin A routed to IRQ 11
> 	Region 0: Memory at fe200000 (32-bit, prefetchable) [size=4K]
> 	Region 1: I/O ports at 2400 [size=32]
> 	Region 2: Memory at fc000000 (32-bit, non-prefetchable) [size=1M]
> 	[virtual] Expansion ROM at 30100000 [disabled] [size=1M]
> 	Kernel driver in use: e100
> 
> 
> I tried to set it up to talk to another machine in order to find
> out where the packets gets lost.  But had another complication
> on the way: it does not "want" to work with 802.1Q VLANs anymore
> at all... ;)
> 
> When pinging this NIC from another machine over VLAN5, I see
> ARP packets coming to it, gets recognized and replies going
> back, all on vlan 5.  But on the other side, replies comes
> WITHOUT a VLAN tag!
> 
> From this NIC's point of view, capturing on whole ethX:
> 
> 00:1f:c6:ef:e5:1b > ff:ff:ff:ff:ff:ff, ethertype 802.1Q (0x8100), length 60: vlan 5, p 0, ethertype ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 10.48.11.2 tell 10.48.11.1, length 42
> 00:90:27:30:6d:1c > 00:1f:c6:ef:e5:1b, ethertype 802.1Q (0x8100), length 46: vlan 5, p 0, ethertype ARP, Ethernet (len 6), IPv4 (len 4), Reply 10.48.11.2 is-at 00:90:27:30:6d:1c, length 28
> 
> From the partner point of view, also on whole ethX:
> 
> 00:1f:c6:ef:e5:1b > ff:ff:ff:ff:ff:ff, ethertype 802.1Q (0x8100), length 46: vlan 5, p 0, ethertype ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 10.48.11.2 tell 10.48.11.1, length 28
> 00:90:27:30:6d:1c > 00:1f:c6:ef:e5:1b, ethertype ARP (0x0806), length 60: Ethernet (len 6), IPv4 (len 4), Reply 10.48.11.2 is-at 00:90:27:30:6d:1c, length 46
> 
> So, the tag gets eaten somewhere along the way... ;)
> 
> And I can't really recreate the situation which I had - I know
> some packets were flowing, so at least ARP worked.  Now it
> does not work anymore.

What the 'partner' setup looks like ?

ip link
ip addr
ip ro


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