[TCP]: TCP Probe congestion window tracing

This adds a new module for tracking TCP state variables non-intrusively
using kprobes.  It has a simple /proc interface that outputs one line
for each packet received. A sample usage is to collect congestion
window and ssthresh over time graphs.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/Kconfig

@@ -215,6 +215,21 @@ config NET_PKTGEN
 	  To compile this code as a module, choose M here: the
 	  module will be called pktgen.
 
+config NET_TCPPROBE
+	tristate "TCP connection probing"
+	depends on INET && EXPERIMENTAL && PROC_FS && KPROBES
+	---help---
+	This module allows for capturing the changes to TCP connection
+	state in response to incoming patckets. It is used for debugging
+	TCP congestion avoidance modules. If you don't understand
+	what was just said, you don't need it: say N.
+
+	Documentation on how to use the packet generator can be found
+	at http://linux-net.osdl.org/index.php/TcpProbe
+
+	To compile this code as a module, choose M here: the
+	module will be called tcp_probe.
+
 endmenu
 
 endmenu