Route classifier in tc

Section: Linux (8)
Updated: 21 Oct 2015
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NAME

route - route traffic control filter

SYNOPSIS

tc filter ... route [ from REALM | fromif TAG ] [ to REALM ] [ classid CLASSID ] [ action ACTION_SPEC ]

DESCRIPTION

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.

OPTIONS

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.

EXAMPLES

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.

NOTES

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.