Re: IP4 Config Troubles with DHCP

["Wu, Jiaxin" <jiaxin.wu@intel.com>]

Hi Eugene,

The formal patch will be sent out next Monday. Currently, I'm not in office, so, I don't have valid DHCP server to verify my fixing. 

Thank you for understanding.

Jiaxin 

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Cohen, Eugene
> Sent: Friday, August 12, 2016 8:35 PM
> To: Wu, Jiaxin <jiaxin.wu@intel.com>; edk2-devel@lists.01.org
> Subject: Re: [edk2] IP4 Config Troubles with DHCP
> 
> > Eugene,
> >
> > I can reproduce the issue now. And root cause as below:
> >
> > #1. Set policy to DHCP.
> > #2. If DHCP process is not complete yet, then run one App to invoke
> > the
> > UDP4 Configure with "UseDefaultAddress = TRUE" (loop to keep calling
> > Udp4->Configure until Ip4Mode.IsConfigured changes to TRUE)
> > #3. Even DHCP succeed but Ip4Mode.IsConfigured flag never set to TRUE
> --
> > -- failure here!!!
> >
> > In step1, the policy will be set to DHCP, and then
> > Ip4Config2OnPolicyChanged() will be called. In this function, "IpSb-
> > >Reconfig" flag will be set to TRUE before Ip4StartAutoConfig()
> > >called. That
> > means the original "IpSb->DefaultInterface" will be abandoned/freed
> > once this DHCP process finished. Detailed see
> > Ip4Config2SetDefaultAddr() function.
> >
> > In step2, UDP4 Configure with "UseDefaultAddress = TRUE" is called,
> > that means the default interface (IpSb->DefaultInterface) will be
> > selected as current instance's interface. Detailed see Ip4ConfigProtocol()
> function.
> >
> > In step3, When DHCP process finished, as I said in step1, the original
> > "IpSb-
> > >DefaultInterface" will be abandoned/freed because "IpSb->Reconfig"
> > >flag is
> > true. Meanwhile, one new interface is assigned to "IpSb-
> >DefaultInterface".
> > This "IpSb->DefaultInterface" is different to the original one
> > assigned to the
> > UDP4 Configured instance. So, even DHCP process succeed, the up caller
> > will never have the chance to get it's truly status.
> >
> > I will send one patch to fix this issue later.
> >
> > Thanks your reporting.
> >
> > Best Regards!
> > Jiaxin
> 
> Jiaxin, excellent to hear.  I'm glad to hear you've isolated the issue.  So the
> service binding instance we have in this case is orphaned which explains why
> destroying it and creating a new one resolves the issue.  Of course we'd be
> happy to test the patch as soon as it's available.
> 
> Thank you!
> 
> Eugene
> 
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