MS DNS doesn't answer to CURRENT under Hyper-V

Wei Hu weh at microsoft.com
Wed Jul 29 07:50:20 UTC 2015


It is already in stable/10 branch. I am just about to send the request to
re@ for releng/10.2 commit approval.

Wei


-----Original Message-----
From: Pavel Timofeev [mailto:timp87 at gmail.com] 
Sent: Wednesday, July 29, 2015 3:48 PM
To: Wei Hu <weh at microsoft.com>
Cc: Slawa Olhovchenkov <slw at zxy.spb.ru>; freebsd-current at freebsd.org; freebsd-virtualization at freebsd.org
Subject: Re: MS DNS doesn't answer to CURRENT under Hyper-V

Hi!
r285785 still isn't MFCed.
RC2 is coming soon.

2015-07-23 10:54 GMT+03:00 Pavel Timofeev <timp87 at gmail.com>:
> Ok, sorry!
>
> 2015-07-23 7:51 GMT+03:00 Wei Hu <weh at microsoft.com>:
>> The TCP offloading is still working on these platforms. There is no flag to distinguish UDP and TCP offloading, so the RXCSUM and TXCSUM are still set. Let me know if there is any other way to show it properly.
>>
>> Thanks,
>> Wei
>>
>>
>> -----Original Message-----
>> From: Pavel Timofeev [mailto:timp87 at gmail.com]
>> Sent: Wednesday, July 22, 2015 9:04 PM
>> To: Wei Hu <weh at microsoft.com>
>> Cc: Slawa Olhovchenkov <slw at zxy.spb.ru>; freebsd-current at freebsd.org; 
>> freebsd-virtualization at freebsd.org
>> Subject: Re: MS DNS doesn't answer to CURRENT under Hyper-V
>>
>> Hi! I see you have done the code for disabling UDP checksum 
>> offloading when running on the Hyper-V on Windows Server 2012 and 
>> earlier hosts
>>
>> https://svnweb.freebsd.org/base?view=revision&revision=285785
>>
>> I tried new CURRENT and it works. Thank you!
>>
>> A small note here: while it disables and works it still shows RXCSUM and TSCSUM in iface's options:
>>
>> root at proxy:/usr/src # ifconfig hn0
>> hn0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
>>         options=31b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,TSO4,TSO6>
>>         ether 00:15:5d:02:9c:09
>>         inet 192.168.25.26 netmask 0xffffffc0 broadcast 192.168.25.63
>>         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>>
>> Is it possible to hide it automatically if it's disabled by new code?
>>
>>
>> 2015-07-13 11:06 GMT+03:00 Wei Hu <weh at microsoft.com>:
>>> We have root caused the problem. This issue happens on the Hyper-Vs on Windows Server 2012 (Win 8.0) and earlier releases. On these releases, the UPD checksum offloading on host side does not work properly. The workaround is to disable UPD checksum offloading in the FreeBSD guest through 'ifconfig'. We are also working on a patch to turn off UPD checksum offloading in the netvsc driver when detecting the Hyper-V releases.
>>>
>>> The UDP checksum offloading works fine on Windows Server 2012R2 and Win 8.1 hosts.
>>>
>>> Thanks Pavel and Slawa for the support.
>>>
>>> Wei
>>>
>>>
>>>> -----Original Message-----
>>>> From: owner-freebsd-virtualization at freebsd.org 
>>>> [mailto:owner-freebsd- virtualization at freebsd.org] On Behalf Of 
>>>> Pavel Timofeev
>>>> Sent: Wednesday, July 8, 2015 4:06 PM
>>>> To: Slawa Olhovchenkov
>>>> Cc: freebsd-current at freebsd.org; freebsd-virtualization at freebsd.org
>>>> Subject: Re: MS DNS doesn't answer to CURRENT under Hyper-V
>>>>
>>>> Ok, r284746 is the root of the problem. MS DNS works under r284745 
>>>> and doesn't work under r284746.
>>>> Slawa, what should I look at in wireshark output?
>>>>
>>>>
>>>> 2015-07-07 18:49 GMT+03:00 Slawa Olhovchenkov <slw at zxy.spb.ru>:
>>>> > On Tue, Jul 07, 2015 at 06:04:46PM +0300, Pavel Timofeev wrote:
>>>> >
>>>> >> Well, turning off checksum offloading by `ifconfig hn0 -txcsum 
>>>> >> -rxcsum` definitely helps.
>>>> >>
>>>> >> As for tcpdump I'm not completely sure if I did it right, but I 
>>>> >> see "bad udp cksum" phrase:
>>>> >>
>>>> >> # tcpdump -i hn0 -vvv -nn udp dst port 53
>>>> >> tcpdump: listening on hn0, link-type EN10MB (Ethernet), capture 
>>>> >> size
>>>> >> 262144 bytes
>>>> >> 18:01:19.139994 IP (tos 0x0, ttl 64, id 61218, offset 0, flags 
>>>> >> [none], proto UDP (17), length 51)
>>>> >>     192.168.25.26.45683 > 192.168.25.3.53: [bad udp cksum 0xb39e
>>>> >> -> 0xf210!] 52886+ A? ya.ru. (23)
>>>> >> 18:01:24.140544 IP (tos 0x0, ttl 64, id 17293, offset 0, flags 
>>>> >> [none], proto UDP (17), length 51)
>>>> >>     192.168.25.26.12575 > 192.168.25.3.53: [bad udp cksum 0xb39e
>>>> >> -> 0x7365!] 52886+ A? ya.ru. (23)
>>>> >
>>>> > tcpdump "bad udp cksum" is normal on FreeBSD host in case 
>>>> > checksum offload (and may be need only for help finding issuse in code).
>>>> > Need wireshark capturing from MS DNS host (or from mirroring port).
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