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.
Apply an action from the generic actions framework on matching packets.
Push matching packets into the class identified by CLASSID.
Perform source route lookups. TAG is the name of an interface which must be present on the system at the time of tc invocation.
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.