To allow configuring user-defined actions as a result of inner workings of
a qdisc, a concept of qevents was recently introduced to the kernel.
Qevents are attach points for TC blocks, where filters can be put that are
executed as the packet hits well-defined points in the qdisc algorithms.
The attached blocks can be shared, in a manner similar to clsact ingress
and egress blocks, arbitrary classifiers with arbitrary actions can be put
on them, etc.
This patch set introduces the corresponding iproute2 support. Patch #1 adds
the new netlink attribute enumerators. Patch #2 adds a set of helpers to
implement qevents, and #3 adds a generic documentation to tc.8. Patch #4
then adds two new qevents to the RED qdisc: mark and early_drop.