tc-route man page
route — route traffic control filter
tc filter ... route [ from REALM | fromif TAG ] [ to REALM ] [ classid CLASSID ] [ action ACTION_SPEC ]
Match packets based on routing table entries. This filter centers around the possibility to assign a realm to routing table entries. For any packet to be classified by this filter, a routing table lookup is performed and the returned realm is used to decide on whether the packet is a match or not.
- action ACTION_SPEC
Apply an action from the generic actions framework on matching packets.
- classid CLASSID
Push matching packets into the class identified by CLASSID.
- from REALM
- fromif TAG
Perform source route lookups. TAG is the name of an interface which must be present on the system at the time of tc invocation.
- to REALM
Match if normal (i.e., destination) routing returns the given REALM.
Consider the subnet 192.168.2.0/24 being attached to eth0:
ip route add 192.168.2.0/24 dev eth0 realm 2
The following route filter will then match packets from that subnet:
tc filter add ... route from 2 classid 1:2
and pass packets on to class 1:2.
Due to implementation details, realm values must be in a range from 0 to 255, inclusive. Alternatively, a verbose name defined in /etc/iproute2/rt_realms may be given instead.