After kernel v4.17 options are added to enable Layer 4 hashing inside the linux kernel.
As we are running 4.19 these options are available to us, bit the ui is missing options to configure it.
more information at:
https://cumulusnetworks.com/blog/celebrating-ecmp-part-two/
The options needed are:
fib_multipath_use_neigh - BOOLEAN Use status of existing neighbor entry when determining nexthop for multipath routes. If disabled, neighbor information is not used and packets could be directed to a failed nexthop. Only valid for kernels built with CONFIG_IP_ROUTE_MULTIPATH enabled. Default: 0 (disabled) Possible values: 0 - disabled 1 - enabled fib_multipath_hash_policy - INTEGER Controls which hash policy to use for multipath routes. Only valid for kernels built with CONFIG_IP_ROUTE_MULTIPATH enabled. Default: 0 (Layer 3) Possible values: 0 - Layer 3 1 - Layer 4