sched: CHOKe flow scheduler

CHOKe ("CHOose and Kill" or "CHOose and Keep") is an alternative
packet scheduler based on the Random Exponential Drop (RED) algorithm.

The core idea is:
  For every packet arrival:
  	Calculate Qave
	if (Qave < minth)
	     Queue the new packet
	else
	     Select randomly a packet from the queue
	     if (both packets from same flow)
	     then Drop both the packets
	     else if (Qave > maxth)
	          Drop packet
	     else
	       	  Admit packet with proability p (same as RED)

See also:
  Rong Pan, Balaji Prabhakar, Konstantinos Psounis, "CHOKe: a stateless active
   queue management scheme for approximating fair bandwidth allocation",
  Proceeding of INFOCOM'2000, March 2000.

Help from:
     Eric Dumazet <eric.dumazet@gmail.com>
     Patrick McHardy <kaber@trash.net>

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index e318f45..8c19b6e 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -217,6 +217,17 @@
 
 	  If unsure, say N.
 
+config NET_SCH_CHOKE
+	tristate "CHOose and Keep responsive flow scheduler (CHOKE)"
+	help
+	  Say Y here if you want to use the CHOKe packet scheduler (CHOose
+	  and Keep for responsive flows, CHOose and Kill for unresponsive
+	  flows). This is a variation of RED which trys to penalize flows
+	  that monopolize the queue.
+
+	  To compile this code as a module, choose M here: the
+	  module will be called sch_choke.
+
 config NET_SCH_INGRESS
 	tristate "Ingress Qdisc"
 	depends on NET_CLS_ACT