[DCCP]: Adds the tx buffer sysctls

This one got lost on the way from Ian to Gerrit to me, fix it.
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

Documentation/networking/dccp.txt

@@ -100,6 +100,10 @@ rx_ccid = 2
 seq_window = 100
 	The initial sequence window (sec. 7.5.2).
 
+tx_qlen = 5
+	The size of the transmit buffer in packets. A value of 0 corresponds
+	to an unbounded transmit buffer.
+
 Notes
 =====
 

include/linux/sysctl.h

@@ -617,6 +617,7 @@ enum {
 	NET_DCCP_DEFAULT_REQ_RETRIES = 7,
 	NET_DCCP_DEFAULT_RETRIES1    = 8,
 	NET_DCCP_DEFAULT_RETRIES2    = 9,
+	NET_DCCP_DEFAULT_TX_QLEN     = 10,
 };
 
 /* /proc/sys/net/ipx */

net/dccp/sysctl.c

@@ -91,6 +91,15 @@ static struct ctl_table dccp_default_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
+	{
+		.ctl_name	= NET_DCCP_DEFAULT_TX_QLEN,
+		.procname	= "tx_qlen",
+		.data		= &sysctl_dccp_tx_qlen,
+		.maxlen		= sizeof(sysctl_dccp_tx_qlen),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+
 	{ .ctl_name = 0, }
 };