sctp: Add sysctl support for Auto-ASCONF.

This patch allows the system administrator to change default
Auto-ASCONF on/off behavior via an sysctl value.

Signed-off-by: Michio Honda <micchie@sfc.wide.ad.jp>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 50cb57f..6b39529 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -183,6 +183,13 @@
 		.proc_handler	= proc_dointvec,
 	},
 	{
+		.procname	= "default_auto_asconf",
+		.data		= &sctp_default_auto_asconf,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
 		.procname	= "prsctp_enable",
 		.data		= &sctp_prsctp_enable,
 		.maxlen		= sizeof(int),