Date: Sat, 13 Jun 2009 10:26:09 +0200 From: Michael Tuexen <tuexen@freebsd.org> To: pyunyh@gmail.com Cc: FreeBSD net mailing list <freebsd-net@freebsd.org>, Andrew Gallatin <gallatin@cs.duke.edu> Subject: Re: Ethernet NIC drivers depending unconditionally on INET Message-ID: <7472C82E-0C52-45AB-9BFF-DD6196B393C9@freebsd.org> In-Reply-To: <20090613080136.GB76872@michelle.cdnetworks.co.kr> References: <20090611184555.J22887@maildrop.int.zabbadoz.net> <20090612013406.GB72855@michelle.cdnetworks.co.kr> <20090612100900.M22887@maildrop.int.zabbadoz.net> <71535CB2-2784-4253-B67E-017FEAD57637@freebsd.org> <4A32F752.90003@cs.duke.edu> <EB178368-A869-4190-BDBC-F88F77C56F6A@freebsd.org> <20090613080136.GB76872@michelle.cdnetworks.co.kr>
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On Jun 13, 2009, at 10:01 AM, Pyun YongHyeon wrote:
> On Sat, Jun 13, 2009 at 09:15:06AM +0200, Michael Tuexen wrote:
>> On Jun 13, 2009, at 2:48 AM, Andrew Gallatin wrote:
>>
>>> Michael Tuexen wrote:
>>>
>>>> I'm not sure if we need additional IFCAP_RXCSUM6 IFCAP_TXCSUM6
>>>> capabilities... Why would we want to enable IPv4 offloading and
>>>> not IPv6 or vice versa?
>>>
>>> I'd assume that some older hardware supports IPv4 offloads, but
>>> might not have support for IPv6 offloads.
>> Sure. But then the driver only provides the CSUM_ flags which
>> are appropriate. For example, a similar thing is already in the
>> igb driver:
>>
>> 1167 if (ifp->if_capenable & IFCAP_TXCSUM) {
>> 1168 ifp->if_hwassist |= (CSUM_TCP | CSUM_UDP);
>> 1169 #if __FreeBSD_version >= 800000
>> 1170 if (adapter->hw.mac.type == e1000_82576)
>> 1171 ifp->if_hwassist |= CSUM_SCTP;
>> 1172 #endif
>> 1173 }
>
> That would disable all IPv4/IPv6 checksum offloading if
> administrator disable IFCAP_TXCSUM. If we have IFCAP_TXCSUM6/
> IFCAP_RXCSUM6 users could choose best working one even if some part
> of driver/controller had checksum offload bugs.
Sure. That is what I wrote in my earlier mail: Do we want to
provide a ability to disable/enable checksum offload for
IPv4 and IPv6 individually...
Besides this "working around bugs" I see no reason to do
it. Some other capabilities TSO/TOE are IPv[46] specific.
I have no strong opinion on this. What do others think?
Best regards
Michael
>
>>
>> For FreeBSD 8 and a particular chip, SCTP checksum offloading
>> is supported. No need for a special IFCAP_TXCSUM.
>>
>> Best regards
>> Michael
>>
>>>
>>> Drew
>>
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