Following up my previous email with output from the machine:
Note that like some of those other people I was able to get ip rule to
accept tos values with just low order bits set
Here is example of how ip rule accepts low order dsfield bits but not modern
DSCP type bits, also including some version info
dlakelan@pingpong:~$ sudo ip rule add dsfield 0x0c table 100
dlakelan@pingpong:~$ ip rule show
0: from all lookup local
32765: from all tos 0x0c lookup 100
32766: from all lookup main
32767: from all lookup default
dlakelan@pingpong:~$ sudo ip rule add dsfield 0xc0 table 100
RTNETLINK answers: Invalid argument
dlakelan@pingpong:~$ cat /proc/version
Linux version 4.12.0-1-amd64 (debian-ker...@lists.debian.org) (gcc version
6.4.0 20170805 (Debian 6.4.0-3) ) #1 SMP Debian 4.12.6-1 (2017-08-12)
dlakelan@pingpong:~$ ip -V
ip utility, iproute2-ss160518
