[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>
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index f30faef..38b8039 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -36,6 +36,7 @@
 obj-$(CONFIG_INET_DIAG) += inet_diag.o 
 obj-$(CONFIG_IP_ROUTE_MULTIPATH_CACHED) += multipath.o
 obj-$(CONFIG_INET_TCP_DIAG) += tcp_diag.o
+obj-$(CONFIG_NET_TCPPROBE) += tcp_probe.o
 obj-$(CONFIG_TCP_CONG_BIC) += tcp_bic.o
 obj-$(CONFIG_TCP_CONG_CUBIC) += tcp_cubic.o
 obj-$(CONFIG_TCP_CONG_WESTWOOD) += tcp_westwood.o