[WireGuard] Source address fib invalidation on IPv6

[Jason A. Donenfeld]

On Sat, Nov 12, 2016 at 8:08 PM, Jason A. Donenfeld <Jason at zx2c4.com> wrote:
>> Gotcha. I don't see any checks that the saddr is valid similar to what IPv4 does.
>>
>> I think the right place to add a check is in ip6_dst_lookup_tail():
>>     if (!ipv6_addr_any(&fl6->saddr)) {
>>         // saddr is valid for L3 domain
>>     }
>
> Right. It should probably do the check here, and return
> ERR_PTR(-EINVAL), the same as the v4 version, so that ret codes can be
> checked consistently.
>
> Thanks for looking into this. If you're backed up and would like me to
> submit a patch, just let me know, and I'll give it my best shot.

In perusing through the v6 FIB code, I don't even see an analog of
__ip_dev_find... Hm?