Re: [PATCH v2] batman-adv: add dynamic, bridged-in TT VID detection support

["Linus Lüssing" <linus.luessing@c0d3.blue>]

And one more thought/idea that just came to my mind:

Maybe after adding dynamic VLAN detection from traffic we
could then also exclude the annoying, actually typically
unused VID 0 from the static addition? That way we would
save quite a bit of overhead as each VLAN currently quite
significantly increases the OGM size.

So basically thinking of simply adding a "if (!vid) return" to
(.ndo_vlan_rx_add_vid =) batadv_interface_add_vid().

One could still use VID 0 on bat0, it just wouldn't be detected as
quickly/immediately, would take an actual payload packet to be added.

Currently VID 0 is added because we set
"dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER" in
batadv_softif_init_early(). Which in turn triggers:
net/8021q/vlan.c:vlan_device_event()->vlan_vid_add(dev, htons(ETH_P_8021Q), 0)
And triggers the message "adding VLAN 0 to HW filter on device bat0"
in dmesg.


But of course, first the BLA induced 30 seconds broadcast
filtering with each added VLAN would need to be solved. As that
might be a too easy DoS potential, I guess?
Could still need some feedback on how to best solve that
(bat_priv->bla.num_requests per VLAN?).

Regards, Linus