Problem with igb and vlans in 2.6.38-rc4
Subsystems (2)
We have a user-space app that uses packet-sockets to grab and send Ethernet frames (basically a user-space bridge).
This has stopped working for VLANs unless we set the physical port MTU to be vlan-MTU + 4 (ie, 1504 for standard MTU size vlan frames). I think this started post 2.6.34 kernel..but not exactly sure at this time.
The test setup is essentially:
client -- vlan 5 -- [ eth4 {software-bridge} eth3 ] -- vlan 5 -- server
The software bridge machine has no VLANs enabled..it is supposed to just read Ethernet frames from one port and xmit out the other.
The bridge machine sees rx-length errors, and if only one port is set to 1504, the other shows xmit errors (since it doesn't like sending a frame 4 bytes larger than MTU probably).
This used to work, and I'm hoping this change wasn't done on purpose.
Thanks,
Ben
Signature · 2 lines
Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com
Quoted 3 lines · Ben Greear
We have a user-space app that uses packet-sockets to grab and send Ethernet frames (basically a user-space bridge).
FYI: I'll post some patches for comment soon..seems I have it working now, just need to clean them up and eat lunch :)
Thanks,
Ben
Quoted 23 lines
This has stopped working for VLANs unless we set the physical port MTU to be vlan-MTU + 4 (ie, 1504 for standard MTU size vlan frames). I think this started post 2.6.34 kernel..but not exactly sure at this time.
The test setup is essentially:
client -- vlan 5 -- [ eth4 {software-bridge} eth3 ] -- vlan 5 -- server
The software bridge machine has no VLANs enabled..it is supposed to just read Ethernet frames from one port and xmit out the other.
The bridge machine sees rx-length errors, and if only one port is set to 1504, the other shows xmit errors (since it doesn't like sending a frame 4 bytes larger than MTU probably).
This used to work, and I'm hoping this change wasn't done on purpose.
Thanks,
Ben
Signature · 2 lines
Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com