[TCP]: Restrict congestion control choices.

Allow normal users to only choose among a restricted set of congestion
control choices.  The default is reno and what ever has been configured
as default. But the policy can be changed by administrator at any time.

For example, to allow any choice:
    cp /proc/sys/net/ipv4/tcp_available_congestion_control \
       /proc/sys/net/ipv4/tcp_allowed_congestion_control

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

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 28a48279654d..0725441621d0 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -427,6 +427,7 @@ enum
         NET_CIPSOV4_RBM_OPTFMT=120,
         NET_CIPSOV4_RBM_STRICTVALID=121,
         NET_TCP_AVAIL_CONG_CONTROL=122,
+        NET_TCP_ALLOWED_CONG_CONTROL=123,
 };
 
 enum {