This same problem as detailed here
http://lists.openwall.net/netdev/2010/03/26/36
or here:
https://www.spinics.net/lists/lartc/msg22541.html
bit me today
I tried either
ip rule add dsfield CS6 table 100
or
ip rule add dsfield 0xc0 table 100
or replace dsfield with tos, all return:
RTNETLINK answers: Invalid argument
on the other hand, for ip route it will accept the ds/tos values
ip route add default dsfield CS6 dev dummy0
or
ip route add default dsfield 0xc0 dev dummy0
but packets tagged with CS6 don't go to dummy0 they go the regular
default route
