hi all,
I need different routes for packets with different TOS values, and tried
to do this with ip. I noticed that ip does not recognice all possible
values for the TOS byte, even when I enter them in
/etc/iproute/rt_dsfield.
to demonstrate this, I added prohibit rules for different marked packets
and tried if the packets are dropped when I try to "ping -Q tosvalue
<somehost>":
#: ip route add prohibit default tos 0xb8
#: ip route add prohibit default tos 0x11
#: ip route add prohibit default tos 0x10
#: ip route add prohibit default tos 0x02
#: ip route
<some rules snipped>
prohibit default tos high
prohibit default tos test
prohibit default tos lowdelay
prohibit default tos mincost
default via 192.168.10.1 dev eth0
#: cat /etc/iproute2/rt_dsfield
0x11 test
0xb8 high
0xbc video
0xe0 burstplan
0x10 lowdelay
0x08 throughput
0x04 reliability
0x02 mincost
so ip look at rt_dsfield and enters the names not the values, that''s
fine. but...
#: ping -Q 0xb8 192.168.10.1
PING 192.168.10.1 (192.168.10.1) from 192.168.10.2 : 56(84) bytes of data.
64 bytes from 192.168.10.1: icmp_seq=0 ttl=254 time=1.919 msec
#: ping -Q 0x11 192.168.10.1
connect: Network is unreachable
#: ping -Q 0x10 192.168.10.1
connect: Network is unreachable
#: ping -Q 0x02 192.168.10.1
PING 192.168.10.1 (192.168.10.1) from 192.168.10.2 : 56(84) bytes of data.
64 bytes from 141.201.123.33: icmp_seq=0 ttl=254 time=1.793 msec
so it works for tos=0x10 and 0x11, but not for tos=0xb8 and 0x02.
it is possible to construct more examples which work, or don''t work,
but I
see no pattern or reason for this strange behavior.
any hints? ideas?
Kurt
