[TCP]: Add tcp_available_congestion_control sysctl.

Create /proc/sys/net/ipv4/tcp_available_congestion_control
that reflects currently available TCP choices.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index fd3c0c012351..db4280856588 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -351,10 +351,16 @@ tcp_frto - BOOLEAN
         where packet loss is typically due to random radio interference
         rather than intermediate router congestion.
 
+tcp_available_congestion_control - STRING
+        Shows the available congestion control choices that are registered.
+        More congestion control algorithms may be available as modules,
+        but not loaded.
+
 tcp_congestion_control - STRING
         Set the congestion control algorithm to be used for new
         connections. The algorithm "reno" is always available, but
         additional choices may be available based on kernel configuration.
+        Default is set as part of kernel configuration.
 
 somaxconn - INTEGER
         Limit of socket listen() backlog, known in userspace as SOMAXCONN.