tcp: Remove TCPCT

TCPCT uses option-number 253, reserved for experimental use and should
not be used in production environments.
Further, TCPCT does not fully implement RFC 6013.

As a nice side-effect, removing TCPCT increases TCP's performance for
very short flows:

Doing an apache-benchmark with -c 100 -n 100000, sending HTTP-requests
for files of 1KB size.

before this patch:
	average (among 7 runs) of 20845.5 Requests/Second
after:
	average (among 7 runs) of 21403.6 Requests/Second

Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 7 deletions

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index cca4550f4082..cb45062c8be0 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -733,13 +733,6 @@ static struct ctl_table ipv4_table[] = {
                 .proc_handler   = proc_dointvec,
         },
         {
-                .procname       = "tcp_cookie_size",
-                .data           = &sysctl_tcp_cookie_size,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = proc_dointvec
-        },
-        {
                 .procname       = "tcp_thin_linear_timeouts",
                 .data           = &sysctl_tcp_thin_linear_timeouts,
                 .maxlen         = sizeof(int),