Re: [PATCH v2] net/ipv6: allow device-only routes via the multipath API

[Nicolas Dichtel]

Le 28/11/2025 à 13:38, azey a écrit :
> On 2025-11-28 09:38:07 +0100  Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx> wrote:
>> With IPv6, unlike IPv4, the ECMP next hops can be added one by one. Your commit
>> doesn't allow this:
>>
>> $ ip -6 route add 2002::/64 via fd00:125::2 dev ntfp2
>> $ ip -6 route append 2002::/64 dev ntfp3
>> $ ip -6 route
>> 2002::/64 via fd00:125::2 dev ntfp2 metric 1024 pref medium
>> 2002::/64 dev ntfp3 metric 1024 pref medium
>> ...
>> $ ip -6 route append 2002::/64 via fd00:175::2 dev ntfp3
>> $ ip -6 route
>> 2002::/64 metric 1024 pref medium
>>         nexthop via fd00:125::2 dev ntfp2 weight 1
>>         nexthop via fd00:175::2 dev ntfp3 weight 1
>>
>> Note that the previous route via ntfp3 has been removed.
> 
> I just tested your example in a VM with my patch, and everything works
> as you described. This is due to fib6_explicit_ecmp not overriding
I tested your patch ;-)

'ip -6 route append 2002::/64 dev ntfp3' failed to add the next hop, a second
route was created.