vlan issues with 7.0-RC3

Christopher Cowart ccowart at rescomp.berkeley.edu
Thu Feb 28 02:38:41 UTC 2008


On Tue, Feb 26, 2008 at 04:43:55PM +0900, Pyun YongHyeon wrote:
>On Mon, Feb 25, 2008 at 01:17:12AM -0800, Christopher Cowart wrote:
>> Hello,
>> 
>> I have a mac mini running 7.0-RC3, which I'm trying to turn it into a
>> router. I have a Linksys SRW2008 "fully managed" (via an IE only web
>> interface, ick) switch. 
>> 
>> Switch:
>>   Port 1 - Trunk vlans 10,60,98 - FreeBSD Box
>>   Port 7 - Access vlan 98 - Existing LAN (192.168.1.0/24)
>> 
>> OpenWRT (192.168.1.1):
>>   WRT54G box on the Existing LAN
>> 
>> FreeBSD Box:
>>   ifconfig msk0 up
>>   ifconfig vlan98 create vlan 98 vlandev msk0 inet 192.168.1.67/24
>> 
>> With this configuration, I can ping hosts on the other lan segment (Port
>> 7). Arp and icmp seem to be quite happy. Unfortunately, I'm not having
>> any luck with tcp and udp. Any attempt to ssh to OpenWRT or dig
>> @OpenWRT hangs indefinitely. If I do a tcpdump, I see the SYN or A?
>> leaving and absolutely no response returning. If I run a tcpdump on
>> OpenWRT, I see no incoming traffic.
>> 
>> When I try to connect *to* the FreeBSD box from the other lan segment, I
>> continue to have problems. tcpdump shows the SYNs arriving via vlan98
>> and the FreeBSD box responding with SYN-ACK. OpenWRT receives the SYNACK.
>> 
>> I disabled ipfw just to be sure (sysctl -w net.inet.ip.fw.enable=0), but
>> it had no effect on the problem. If I connect the FreeBSD box to a vlan
>> 98 access port and assign the address to msk0, my connectivity problems
>> go away. This leads me to believe that the firewall on OpenWRT is not
>> the problem and the problem is related to vlans.
>> 
>> Thinking it was a problem with the not-so-cheap Linksys POS (bitterness
>> about the IE web interface again), I plugged my MacBook (running
>> Leopard, not FreeBSD) into the trunk port. Running the ifconfig commands
>> above (s/msk0/en0/), I got up and running without any problems. This
>> causes me to suspect the FreeBSD box.
>> 
>> Does anyone have any idea what's going on here? Any suggestions for
>> further troubleshooting?
>> 
>
> Try disabling hardware features one by one in msk(4) and see how
> it goes.
>  o Disable TSO.
>  o Disable Tx checksum offload.
>  o Disable VLAN hardware tagging.

Works great after `sudo ifconfig msk0 -txcsum'. 

Is this a known bug, or should I file a PR? Let me know if there are any
other details I can provide to help somebody squash it.

Thanks,

-- 
Chris Cowart
Network Technical Lead
Network & Infrastructure Services, RSSP-IT
UC Berkeley
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