[U-Boot] [PATCH 1/2] efi_loader: initialize ethernet device path fully

[Heinrich Schuchardt]

On 03/25/2018 10:11 PM, Heinrich Schuchardt wrote:
> On 03/25/2018 07:31 PM, Patrick Wildt wrote:
>> On Fri, Mar 23, 2018 at 07:58:07PM +0100, Heinrich Schuchardt wrote:
>>> On 03/23/2018 07:54 PM, Heinrich Schuchardt wrote:
>>>> >From c38a011f699cf5a41b48c6fc547f3d0dde3d7cf9 Mon Sep 17 00:00:00 2001
>>>> From: Patrick Wildt <patrick at blueri.se>
>>>> Date: Fri, 23 Mar 2018 15:36:58 +0100
>>>> Subject: [PATCH 1/2] efi_loader: initialize ethernet device path fully
>>>>
>>>> Since the backing memory for a new device path can contain stale
>>>> data we have to make sure that we either zero the buffer or that
>>>> we initialize all variables in the overlaying structure.  This
>>>> fixes setting the boot device path in the loaded image protocol
>>>> in case we boot from network.>
>>>> Signed-off-by: Patrick Wildt <patrick at blueri.se>
>>>> ---
<snip>
> 
>>
>>>
>>>> +	ndp->if_type = 1;
>>>
>>> This line does not give any clue what 1 relates to. Please, define a
>>> constant. EDK uses NET_IFTYPE_ETHERNET = 1.
>>>
>>> The UEFI spec refers to RFC3232. But I could not find the corresponding
>>> definition there.
>>> https://www.iana.org/assignments/ianaiftype-mib/ianaiftype-mib uses the
>>> value 6 for Ethernet interfaces.
>>>
>>> Please, provide the RFC or IANA page from which you have taken the value
>>> 1 in a comment for the constant.
>>
>> I guess I should have added /* Ethernet */ as comment, which would be as
>> precise information as given in the function dp_fill(void) where this
>> was introduced as part of commit 9dfd84da8ce :
>>
>> +		/* Ethernet */
>> +		dp->if_type = 1;
> 
> You got me. We should use the same constant here, too. I still do not
> know in which spec this value of 1 is really defined.
> 
> Best regards
> 
> Heinrich
> 

The UEFI spec 2.7 says for IfType:
Network interface type(i.e., 802.3, FDDI). See RFC 3232

RFC 3232 says that we should use the numbers published on www.iana.org.

https://www.iana.org/assignments/ianaiftype-mib/ianaiftype-mib has these
values for ifType

other: 1
ethernetCsmacd: 6 for all ethernet-like interfaces, as per RFC 3635

For converting device paths the UEFI specs requires:
"If IfType  is 0 or 1, then the MacAddr must be exactly six bytes."

For compatibility's sake we should stick with the value 1. But, please,
define a constant and use it wherever iftype is set.

Best regards

Heinrich