Re: [PATCH 3/3] Report IP network prefix in XenStore

[Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx>]

On 28/07/2026 16:31, Owen Smith wrote:
> 
>> @@ -735,7 +761,7 @@ FrontendDumpIPv6Address(
>>       _In_ PXENVIF_ADDRESS            Entry
>>       )
>>   {
>> -    CHAR                            Node[sizeof ("ipv6/XXXXXXXXXX")];
>> +    CHAR                            Node[sizeof ("ipv6/XXXXXXXXXX/prefix")];
>>       ULONG                           Index;
>>       ULONG                           Count;
>>       ULONG                           ZeroIndex;
>> @@ -823,6 +849,26 @@ FrontendDumpIPv6Address(
>>       if (!NT_SUCCESS(status))
>>           return status;
>>
>> +    if (Entry->Prefix > 128)
>> +        return STATUS_SUCCESS;
>> +
>> +    status = RtlStringCbPrintfA(Node,
>> +                                sizeof (Node),
>> +                                "ipv6/%u/prefix",
>> +                                AddressIndex);
>> +    if (!NT_SUCCESS(status))
>> +        return status;
>> +
>> +    status = XENBUS_STORE(Printf,
>> +                          &Frontend->StoreInterface,
>> +                          Transaction,
>> +                          __FrontendGetPrefix(Frontend),
>> +                          Node,
>> +                          "%hhu",
>> +                          Entry->Prefix);
>> +    if (!NT_SUCCESS(status))
>> +        return status;
>> +
>>       return STATUS_SUCCESS;
>>   }
> 
> Is it intentional to potentially leave a 'prefix' value if Prefix <= 128?
> Should "ipv6/%u/prefix" value be removed if Entry->Prefix <= 128

StoreRemove is called on the entire ipv4/ipv6 key before writing to 
xenstore: 
https://github.com/xcp-ng/win-xenvif/blob/1982ec64f82bc157e6bf15dd19f9106ef01a59bd/src/xenvif/frontend.c#L800

So removing the prefix value shouldn't be needed in this case.

> 
> Owen



--
Ngoc Tu Dinh | Vates XCP-ng Developer

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