On Monday, 25 February 2019 17:00:46 CET Linus Lüssing wrote: [...]
Disable batman-adv and try a broadcast ping like "ping6 ff02::1%adhoc0" and unicast ones. If that works with 6 nodes, but not with 7 ones then you know it's not batman-adv's fault.
This is only true when the driver/firmware handles multicast frames as broadcasts. I have already seen some of them converting the multicast/unicast frames to unicast frames in such situations. This also broke OGM detection on batman-adv because we only accept broadcast OGMs received as broadcast - otherwise the OGM metric stuff wouldn't make any sense at all.
And you have to do this in both directions to check whether bidirectional links are available. A ping6 answer (icmp echo reply) is unicast - and you also need the check the broadcast stuff in both direction.
But yes, when even this test fails then it is definitely not batman-adv's fault. Just keep in mind that a working ping6 doesn't have to mean that it is batman-adv's fault.
Kind regard, Sven