Re: [PATCH net-next] hyperv: Add handler for RNDIS_STATUS_NETWORK_CHANGE event

Am 30.10.2015 um 23:03 schrieb Haiyang Zhang:

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-----Original Message-----
From: Vitaly Kuznetsov [mailto:vkuznets@redhat.com]
Sent: Friday, October 30, 2015 6:56 AM
To: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Richard Weinberger <redacted>; David Miller
[off-list ref]; olaf@aepfle.de; jasowang@redhat.com; driverdev-
devel@linuxdriverproject.org; LKML [off-list ref];
netdev@vger.kernel.org
Subject: Re: [PATCH net-next] hyperv: Add handler for
RNDIS_STATUS_NETWORK_CHANGE event

Haiyang Zhang [off-list ref] writes:

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-----Original Message-----
From: Richard Weinberger [mailto:richard.weinberger@gmail.com]
Sent: Tuesday, October 27, 2015 6:36 PM
To: David Miller <davem@davemloft.net>
Cc: Haiyang Zhang <haiyangz@microsoft.com>; olaf@aepfle.de; Greg

Kroah-

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Hartman [off-list ref]; netdev@vger.kernel.org; jasowang@redhat.com;
driverdev-devel@linuxdriverproject.org; LKML <linux-
kernel@vger.kernel.org>
Subject: Re: [PATCH net-next] hyperv: Add handler for
RNDIS_STATUS_NETWORK_CHANGE event

On Mon, Jun 23, 2014 at 10:10 PM, David Miller [off-list ref]
wrote:

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From: Haiyang Zhang <haiyangz@microsoft.com>
Date: Mon, 23 Jun 2014 16:09:59 +0000

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So, what's the equivalent or similar command to "network restart"

on

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SLES12? Could

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you update the command line for the usermodehelper when porting

this

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patch to SLES

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12?

No, you are not going to keep the usermodehelper invocation in your

driver

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please remove it.  It is absolutely inappropriate, and I strictly

do

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not want

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to keep it in there because other people will copy it and then

we'll

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have a

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real mess on our hands.

Sorry for digging up this old thread.
While talking with some guys about usermodehelper abuses I came

across

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this gem.
Mainline still contains that "/etc/init.d/network restart" code.
Haiyang, care to cleanup?

Hi Richard and others,

Thanks for the reminder. I will clean up the usermode helper.

Do you have suggestions of trigger DHCP refresh from kernel mode? Any
sample code in the existing kernel code?

I think it's wrong to call dhcp refresh from kernel. What happens when
we reconnect normal hardware adapter to another network? Link goes down
and then up and userspace is supposed to react accordingly. I think we
should emulate something similar for RNDIS_STATUS_NETWORK_CHANGE.

When link is down physically for a few seconds, the DHCP will automatically 
refresh. I will add code to emulate this. There were some discussions around 
this and other possibilities previously... I agree emulating what happens 
with physically plug/unplug a cable is a reasonable way to trigger the DHCP 
refresh.

Can't you propagate the event to userspace and let it take an appropriate
action?

Thanks,
//richard