Re: Unsolicited Neighbor Solicitations disabled for 20 years

[christos%astron.com@localhost (Christos Zoulas)]

In article <20210812144716.GR826%trav.math.uni-bonn.de@localhost>,
Edgar Fuß  <ef%math.uni-bonn.de@localhost> wrote:
>> Is there a way of manually triggering an Unsolicited Neighbor Solicitation 
>> (the IPv6 equivalent of a gratuitous ARP)?
>> 
>> When adding an adress to an interface, one should be sent, but I see only the 
>> DAD and a Mulicast join.
>After digging through the source for the past days, I've made some progress.
>
>It looks like the code paths for generating GARPs and Unsol NAs are completely 
>different because ARP is an ethernet-only thing while ND is L2 agnostic.
>
>So while GARPs are generated in lla_rt_output() in the RTM_ADD case, Unsol NAs 
>should probably be generated in nd6_rtrequest() (which ifa_rtrequest points to 
>in the IPv6 case). But the code part that seems should in fact generate them 
>is #if 0'd out with a comment /* XXX it does not work */ for more than 
>20 years. Unfortunately, itojun@ is no longer with us to explain why he 
>disabled that part.
>
>Any experts on this area? Would it make sense to look at how other projects 
>using KAME (who would that be?) handle that case?

What does FreeBSD/OpenBSD do?

christos