On Tue, 6 Jan 2026 13:04:41 +0100 Oliver Hartkopp wrote:

When such skb is echo'ed back after successful transmission via 
netif_rx() this leads to skb->skb_iif = skb->dev->ifindex;

To prevent a loopback the CAN frame must not be sent back to the 
originating interface - even when it has been routed to different CAN 
interfaces in the meantime (which always overwrites skb_iif).

Therefore we need to maintain the "real original" incoming interface.

Alternatively perhaps for this particular use case you could use
something like metadata_dst to mark the frame as forwarded / annotate
with the originating ifindex?