em(4): sending ARP regardless of NOARP flag

[Xin LI]

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Li, Qing wrote:
> Is this on -CURRENT ?

No, it's 7.2-RELEASE-p2.

> --Qing
> 
> 
>> -----Original Message-----
>> From: owner-freebsd-net at freebsd.org [mailto:owner-freebsd-
>> net at freebsd.org] On Behalf Of Xin LI
>> Sent: Monday, August 03, 2009 12:40 PM
>> To: Jack F Vogel
>> Cc: freebsd-net at freebsd.org
>> Subject: em(4): sending ARP regardless of NOARP flag
>>
> Hi, Jack,
> 
> I have observed that, even if -arp is specified when adding an IP
> address to the em(4) interface, an ARP request is still being sent.
> Here is a tcpdump from my network environment:
> 
> 11:15:01.370256 00:13:72:66:b5:d7 > ff:ff:ff:ff:ff:ff, ethertype ARP
> (0x0806), length 60: Request who-has *.*.152.120 tell *.*.152.120,
> length 46
> 11:15:01.370270 00:15:17:92:39:0e > 00:13:72:66:b5:d7, ethertype ARP
> (0x0806), length 42: Reply *.*.152.120 is-at 00:00:5e:00:01:07, length
> 28
> 
> (The first ARP request was sent from a Dell branded Intel 82541EI
>> based
> NIC, the latter is from a cheaper server that is part of CARP
> configuration which is unrelated to the problem in response to the ARP
> request)
> 
> I was originally under the impression that there is some bug in our
>> ARP
> code but with a bce(4) card, the problem does not exist.  After a
> glance
> at e1000 driver code, it looks like that the e1000 NIC has a feature
>> of
> hardware interception of ARP, can this be somehow connected?  The
> hardware in question is 82541EI based:
> 
> em1 at pci0:7:8:0:	class=0x020000 card=0x016d1028 chip=0x10768086
> rev=0x05
> hdr=0x00
>     vendor     = 'Intel Corporation'
>     device     = '82541EI Gigabit Ethernet Controller'
>     class      = network
>     subclass   = ethernet
> 
> Thanks in advance!
> 
> Cheers,
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- --
Xin LI <delphij at delphij.net>	http://www.delphij.net/
FreeBSD - The Power to Serve!
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