[OE-core] busybox: udhcpc: fix IPv6 support when using udhcpc

[Khem Raj]

On 1/20/20 4:57 AM, Stefan Agner wrote:
> On 2020-01-20 13:32, Quentin Schulz wrote:
>> Hi all,
>>
>> On Mon, Jan 13, 2020 at 03:57:31PM +0100, Quentin Schulz wrote:
>>> Hi all,
>>>
>>> On Mon, May 14, 2018 at 04:44:15PM +0200, Stefan Agner wrote:
>>>> From: Stefan Agner <stefan.agner at toradex.com>
>>>>
>>>> The udhcpc script calls ip addr flush .. which flushes addresses
>>>> of any address family, including IPv6. However, busybox udhcpc is
>>>> IPv4 only and should not influence IPv6 addressing. Hence use ip
>>>> addr flush with family constrait.
>>>>
>>>> The script particularly broke IPv6 SLAAC: Typically when udhcpc
>>>> calls the script the kernel already assigned the IPv6 link-local
>>>> address. The flush removes the link-local IPv6 address again and
>>>> prohibits proper IPv6 operation such as SLAAC since neighbor
>>>> discovery protocol relies on IPv6 link-local addressing.
>>>>
>>>> Signed-off-by: Stefan Agner <stefan.agner at toradex.com>
>>>> ---
>>>>   meta/recipes-core/busybox/files/simple.script | 2 +-
>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/meta/recipes-core/busybox/files/simple.script b/meta/recipes-core/busybox/files/simple.script
>>>> index 6ed0293525..8b5eb53633 100644
>>>> --- a/meta/recipes-core/busybox/files/simple.script
>>>> +++ b/meta/recipes-core/busybox/files/simple.script
>>>> @@ -28,7 +28,7 @@ case "$1" in
>>>>   		fi
>>>>   		if ! root_is_nfs ; then
>>>>                           if [ $have_bin_ip -eq 1 ]; then
>>>> -                                /SBIN_DIR/ip addr flush dev $interface
>>>> +                                /SBIN_DIR/ip -4 addr flush dev $interface
>>>>                                   /SBIN_DIR/ip link set dev $interface up
>>>>                           else
>>>>                                   /SBIN_DIR/ifconfig $interface 0.0.0.0
>>>
>>> Kindly pinging, happened to us as well many times.
>>>
>>
>> Kindly pinging.
> 
> Just checked, we still override that script in our layer, so definitely
> would be happy if this gets merged upstream so I can get rid of our
> custom script downstream.
> 

I think this is good to go got OE-core, but I was wondering if default 
script in busybox also need this and perhaps upstream too

> --
> Stefan
>