Re: [PATCH] net: ipv6: don't generate link-local address in any addr_gen_mode

From: David Ahern
Date: Thu Jul 01 2021 - 00:41:54 EST


On 6/30/21 9:39 PM, Rocco Yue wrote:
> On Wed, 2021-06-30 at 21:03 -0600, David Ahern wrote:
> On 6/30/21 7:59 PM, Rocco Yue wrote:
>>> This patch provides an ipv6 proc file named
>>> "disable_gen_linklocal_addr", its absolute path is as follows:
>>> "/proc/sys/net/ipv6/conf/<iface>/disable_gen_linklocal_addr".
>>>
>>> When the "disable_gen_linklocal_addr" value of a device is 1,
>>> it means that this device does not need the Linux kernel to
>>> automatically generate the ipv6 link-local address no matter
>>> which IN6_ADDR_GEN_MODE is used.
>>>
>>
>> doesn't this duplicate addr_gen_mode == 1 == IN6_ADDR_GEN_MODE_NONE?
>>
>
> Hi David,
>
> Thanks for your review.
>
> This patch is different with IN6_ADDR_GEN_MODE_NONE.
>
> When the addr_gen_mode == IN6_ADDR_GEN_MODE_NONE, the Linux kernel
> doesn't automatically generate the ipv6 link-local address.
>

...

>
> After this patch, when the "disable_gen_linklocal_addr" value of a device
> is 1, no matter in which addr_gen_mode, the Linux kernel will not automatically
> generate an ipv6 link-local for this device.
>

those 2 sentences are saying the same thing to me.

for your use case, why is setting addr_gen_mode == 1 for the device not
sufficient?