答复: [DxeNetLib] Why do we restrict each field to have the same leading zero format?

[Guoheyi <guoheyi@huawei.com>]

Many thanks. I missed to check the latest cod...

Regards,

Gary (Heyi Guo)

-----邮件原件-----
发件人: Wu, Jiaxin [mailto:jiaxin.wu@intel.com] 
发送时间: 2017年4月6日 13:30
收件人: Guoheyi; edk2-devel@lists.01.org
抄送: Tian, Feng; Fu, Siyuan; Zeng, Star
主题: RE: [edk2] [DxeNetLib] Why do we restrict each field to have the same leading zero format?

Hi Gary,

The issue has been gone since the version of 9f5ca5efbd0bb00c9d3577b95e6322e85cb0b118. Please check that.

Thanks,
Jiaxin

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of 
> Guoheyi
> Sent: Wednesday, April 5, 2017 6:56 PM
> To: edk2-devel@lists.01.org
> Cc: Tian, Feng <feng.tian@intel.com>; Wu, Jiaxin 
> <jiaxin.wu@intel.com>; Fu, Siyuan <siyuan.fu@intel.com>; Zeng, Star 
> <star.zeng@intel.com>
> Subject: [edk2] [DxeNetLib] Why do we restrict each field to have the 
> same leading zero format?
> 
> Hi folks,
> 
> We are using NetLibAsciiStrToIp6 function in DxeNetLib.c of 
> MdeModulePkg to convert string to IPv6 address. We found this function 
> will return invalid parameter with below input:
> 2001:3456:789a:0000:f012:2:2003:2005
> 
> We trace the code and believe it is handled by the branch in line 2955:
> 
>       if ((Cnt != 0) && (Cnt < 4) && LeadZero) {
>         return EFI_INVALID_PARAMETER;
>       }
> 
> I think the reason is that we have field 3 of "0000" which has leading 
> zero and causes LeadZero flag to be true, and it requires all the 
> following fields to have the same leading zero format, while field 5 of "2" is not.
> 
> I checked RFC 4291 and only found below text; I didn't find any 
> restriction that requires each field to have the same leading zero format.
> 
>    1. The preferred form is x:x:x:x:x:x:x:x, where the 'x's are one to
>       four hexadecimal digits of the eight 16-bit pieces of the address.
>       Examples:
> 
>          ABCD:EF01:2345:6789:ABCD:EF01:2345:6789
> 
>          2001:DB8:0:0:8:800:200C:417A
> 
>       Note that it is not necessary to write the leading zeros in an
>       individual field, but there must be at least one numeral in every
>       field (except for the case described in 2.).
> 
> Could you help to confirm whether it is a bug or there is some special 
> reason for this?
> 
> Thanks and regards,
> 
> Gary (Heyi Guo)
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