vlan tag packet is stripped in eth1 not in eth2 interface?

sargurus · 04-02-2014, 02:00 AM

After reboot the box:
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eth 1 Interface:
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[root@Linux ~]# ethtool -d eth1 | grep -i vlan
VLAN mode: disabled
VLAN filter: enabled

[root@Linux ~]# ifconfig eth1 promisc

[root@Linux ~]# ethtool -d eth1 | grep -i vlan //After change the promisc mode in eth1 :
VLAN mode: enabled
VLAN filter: disabled
[root@Linux ~]#

[root@Linux ~]# ifconfig eth1 –promisc

[root@Linux ~]# ethtool -d eth1 | grep -i vlan
VLAN mode: disabled
VLAN filter: enabled

[root@Linux ~]# ethtool -K eth1 rxvlan off
Cannot set device flag settings: Operation not supported
[root@Linux ~]#
[root@Linux ~]# uname -a
Linux Centos-2.6.32-431.5.1.el6.i686 #1 SMP Tue Feb 11 21:56:33 UTC 2014 i686 i686 i386 GNU/Linux

lspci for eth1:
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01:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection
Subsystem: Intel Corporation Device 202c
Flags: bus master, fast devsel, latency 0, IRQ 17
Memory at d0120000 (32-bit, non-prefetchable) [size=128K]
Memory at d0100000 (32-bit, non-prefetchable) [size=128K]
I/O ports at 2000 [size=32]
Memory at d0140000 (32-bit, non-prefetchable) [size=16K]
Capabilities: [c8] Power Management version 2
Capabilities: [d0] MSI: Enable- Count=1/1 Maskable- 64bit+
Capabilities: [e0] Express Endpoint, MSI 00
Capabilities: [a0] MSI-X: Enable+ Count=5 Masked-
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Device Serial Number 00-22-4d-ff-ff-88-da-6c
Kernel driver in use: e1000e
Kernel modules: e1000e

02:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection
Subsystem: Intel Corporation Device 202c
Flags: bus master, fast devsel, latency 0, IRQ 16
Memory at d0220000 (32-bit, non-prefetchable) [size=128K]
Memory at d0200000 (32-bit, non-prefetchable) [size=128K]
I/O ports at 3000 [size=32]
Memory at d0240000 (32-bit, non-prefetchable) [size=16K]
Capabilities: [c8] Power Management version 2
Capabilities: [d0] MSI: Enable- Count=1/1 Maskable- 64bit+
Capabilities: [e0] Express Endpoint, MSI 00
Capabilities: [a0] MSI-X: Enable+ Count=5 Masked-
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Device Serial Number 00-22-4d-ff-ff-88-da-6f
Kernel driver in use: e1000e
Kernel modules: e1000e

eth2 interface:
***************
[root@Linux ~]# ethtool -d eth2 | grep -i vlan
VLAN mode: disabled
VLAN filter: disabled

[root@Linux ~]# ifconfig eth2 promisc

[root@Linux ~]# ethtool -d eth2 | grep -i vlan // After change the promisc mode in eth2 :
VLAN mode: disabled
VLAN filter: disabled
[root@Linux ~]#

[root@Linux ~]# ifconfig eth2 –promisc

[root@Linux ~]# ethtool -d eth2 | grep -i vlan
VLAN mode: disabled
VLAN filter: disabled

lspci for eth2:
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03:00.0 Ethernet controller: Intel Corporation 82541PI Gigabit Ethernet Controller (rev 05)
Subsystem: Intel Corporation PRO/1000 GT Desktop Adapter
Flags: bus master, 66MHz, medium devsel, latency 32, IRQ 20
Memory at d0020000 (32-bit, non-prefetchable) [size=128K]
Memory at d0000000 (32-bit, non-prefetchable) [size=128K]
I/O ports at 1000 [size=64]
Expansion ROM at d0600000 [disabled] [size=128K]
Capabilities: [dc] Power Management version 2
Capabilities: [e4] PCI-X non-bridge device
Kernel driver in use: e1000
Kernel modules: e1000
Question -1
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In my Linux Application, I turn the promiscuous mode ON to see all the packets coming in to this interface.However, I receive the packets with vlan tag stripped.I am able to see vlan tagged packet in tcpdump.

Is this the expected behavior in Cent OS(Please see above for the exact configs) ?

I see the same working fine for <Intel Corporation 82574L Gigabit Network Connection - e1000> in the same box, but not in <Intel Corporation 82574L Gigabit Network Connection - e1000e>

Question -2:
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I tried to turn off rxvlan offloading through the ethtool –K command. However, it did not work
Is this an expected behavior and are there any other ways to turn it off through commands/configs ?

I browsed through and hit the below match.
https://www.mail-archive.com/e1000-d.../msg09044.html
Is there an alternate way ? Is it required to rebuild the complete linux kernel for this change ?

Thanks
Saravanan