[TCP]: Add TCP Hybla congestion control module.

TCP Hybla congestion avoidance.

- "In heterogeneous networks, TCP connections that incorporate a
terrestrial or satellite radio link are greatly disadvantaged with
respect to entirely wired connections, because of their longer round
trip times (RTTs). To cope with this problem, a new TCP proposal, the
TCP Hybla, is presented and discussed in the paper[1]. It stems from an
analytical evaluation of the congestion window dynamics in the TCP
standard versions (Tahoe, Reno, NewReno), which suggests the necessary
modifications to remove the performance dependence on RTT.[...]"[1]

[1]: Carlo Caini, Rosario Firrincieli, "TCP Hybla: a TCP enhancement for
heterogeneous networks",
International Journal of Satellite Communications and Networking
Volume 22, Issue 5 , Pages 547 - 566. September 2004.

Signed-off-by: Daniele Lacamera (root at danielinux.net)net
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 910e25b..516ffe8 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -478,6 +478,16 @@
 	increase the congestion window by when an ACK is received.
  	For more detail	see http://www.icir.org/floyd/hstcp.html
 
+config TCP_CONG_HYBLA
+	tristate "TCP-Hybla congestion control algorithm"
+	depends on INET && EXPERIMENTAL
+	default n
+	---help---
+	TCP-Hybla is a sender-side only change that eliminates penalization of
+	long-RTT, large-bandwidth connections, like when satellite legs are
+	involved, expecially when sharing a common bottleneck with normal
+	terrestrial connections.
+
 endmenu
 
 source "net/ipv4/ipvs/Kconfig"