[SCTP] ADDIP: Add sysctl parameter to enable/disable addip.

include/linux/sysctl.h

@@ -576,6 +576,7 @@ enum {
 	NET_SCTP_HB_INTERVAL             = 10,
 	NET_SCTP_PRESERVE_ENABLE         = 11,
 	NET_SCTP_MAX_BURST               = 12,
+	NET_SCTP_ADDIP_ENABLE		 = 13,
 };
 
 /* CTL_PROC names: */

include/net/sctp/structs.h

@@ -190,6 +190,9 @@ extern struct sctp_globals {
 	 */
 	struct list_head local_addr_list;
 	spinlock_t local_addr_lock;
+	
+	/* Flag to indicate if addip is enabled. */
+	int addip_enable;
 } sctp_globals;
 
 #define sctp_rto_initial		(sctp_globals.rto_initial)
@@ -217,6 +220,7 @@ extern struct sctp_globals {
 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
 #define sctp_local_addr_list		(sctp_globals.local_addr_list)
 #define sctp_local_addr_lock		(sctp_globals.local_addr_lock)
+#define sctp_addip_enable		(sctp_globals.addip_enable)
 
 /* SCTP Socket type: UDP or TCP style. */
 typedef enum {

net/sctp/protocol.c

@@ -1115,6 +1115,9 @@ __init int sctp_init(void)
 			 "(established %d bind %d)\n",
 		sctp_assoc_hashsize, sctp_port_hashsize);
 
+	/* Disable ADDIP by default. */
+	sctp_addip_enable = 0;
+
 	sctp_sysctl_register();
 
 	INIT_LIST_HEAD(&sctp_address_families);

net/sctp/sm_statetable.c

@@ -924,11 +924,13 @@ const sctp_sm_table_entry_t *sctp_chunk_event_lookup(sctp_cid_t cid,
 	if (cid >= 0 && cid <= SCTP_CID_BASE_MAX)
 		return &chunk_event_table[cid][state];
 
+	if (sctp_addip_enable) {
 		if (cid == SCTP_CID_ASCONF)
 			return &addip_chunk_event_table[0][state];
 
 		if (cid == SCTP_CID_ASCONF_ACK)
 			return &addip_chunk_event_table[1][state];
+	}
 
 	return &chunk_event_table_unknown[state];
 }

net/sctp/socket.c

@@ -379,6 +379,9 @@ static int sctp_send_asconf_add_ip(struct sock		*sk,
 	int 				i;
 	int 				retval = 0;
 
+	if (!sctp_addip_enable)
+		return retval;
+
 	sp = sctp_sk(sk);
 	ep = sp->ep;
 
@@ -564,6 +567,9 @@ static int sctp_send_asconf_del_ip(struct sock		*sk,
 	int 			i;
 	int 			retval = 0;
 
+	if (!sctp_addip_enable)
+		return retval;
+
 	sp = sctp_sk(sk);
 	ep = sp->ep;
 

net/sctp/sysctl.c

@@ -162,6 +162,14 @@ static ctl_table sctp_table[] = {
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec
 	},
+	{
+		.ctl_name	= NET_SCTP_ADDIP_ENABLE,
+		.procname	= "addip_enable",
+		.data		= &sctp_addip_enable,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
 	{ .ctl_name = 0 }
 };