llc: Add CoDel AQM implementation

This commit adds an implementation of the CoDel algorithm based on
the reference pseudocode presented in
http://queue.acm.org/appendices/codel.html. Instead of abstracting
the queue itself, the implementation provides a time stamp based
automaton which is invoked after a package has been dequeued.

Note that the modifications of the algorithm shown in
https://tools.ietf.org/html/draft-ietf-aqm-codel-01 are not yet
applied.

Sponsored-by: On-Waves ehf
diff --git a/tests/testsuite.at b/tests/testsuite.at
index d7a85e5..71179d1 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -50,3 +50,9 @@
 cat $abs_srcdir/llist/LListTest.err > experr
 AT_CHECK([$OSMO_QEMU $abs_top_builddir/tests/llist/LListTest], [0], [expout], [experr])
 AT_CLEANUP
+
+AT_SETUP([codel])
+AT_KEYWORDS([codel])
+cat $abs_srcdir/codel/codel_test.ok > expout
+AT_CHECK([$OSMO_QEMU $abs_top_builddir/tests/codel/codel_test], [0], [expout], [ignore])
+AT_CLEANUP