[SCTP] Fix sctp_get{pl}addrs() API to work with 32-bit apps on 64-bit kernels.

The old socket options are marked with a _OLD suffix so that the
existing 32-bit apps on 32-bit kernels do not break.
Signed-off-by: Ivan Skytte Jrgensen <isj-sctp@i1.dk>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sctp/user.h

@@ -103,16 +103,20 @@ enum sctp_optname {
 #define SCTP_SOCKOPT_BINDX_REM	SCTP_SOCKOPT_BINDX_REM
 	SCTP_SOCKOPT_PEELOFF, 	/* peel off association. */
 #define SCTP_SOCKOPT_PEELOFF	SCTP_SOCKOPT_PEELOFF
-	SCTP_GET_PEER_ADDRS_NUM, 	/* Get number of peer addresss. */
-#define SCTP_GET_PEER_ADDRS_NUM	SCTP_GET_PEER_ADDRS_NUM
+	SCTP_GET_PEER_ADDRS_NUM_OLD, 	/* Get number of peer addresss. */
+#define SCTP_GET_PEER_ADDRS_NUM_OLD	SCTP_GET_PEER_ADDRS_NUM_OLD
+	SCTP_GET_PEER_ADDRS_OLD, 	/* Get all peer addresss. */
+#define SCTP_GET_PEER_ADDRS_OLD	SCTP_GET_PEER_ADDRS_OLD
+	SCTP_GET_LOCAL_ADDRS_NUM_OLD, 	/* Get number of local addresss. */
+#define SCTP_GET_LOCAL_ADDRS_NUM_OLD	SCTP_GET_LOCAL_ADDRS_NUM_OLD
+	SCTP_GET_LOCAL_ADDRS_OLD, 	/* Get all local addresss. */
+#define SCTP_GET_LOCAL_ADDRS_OLD	SCTP_GET_LOCAL_ADDRS_OLD
+	SCTP_SOCKOPT_CONNECTX, /* CONNECTX requests. */
+#define SCTP_SOCKOPT_CONNECTX	SCTP_SOCKOPT_CONNECTX
 	SCTP_GET_PEER_ADDRS, 	/* Get all peer addresss. */
 #define SCTP_GET_PEER_ADDRS	SCTP_GET_PEER_ADDRS
-	SCTP_GET_LOCAL_ADDRS_NUM, 	/* Get number of local addresss. */
-#define SCTP_GET_LOCAL_ADDRS_NUM	SCTP_GET_LOCAL_ADDRS_NUM
 	SCTP_GET_LOCAL_ADDRS, 	/* Get all local addresss. */
 #define SCTP_GET_LOCAL_ADDRS	SCTP_GET_LOCAL_ADDRS
-	SCTP_SOCKOPT_CONNECTX, /* CONNECTX requests. */
-#define SCTP_SOCKOPT_CONNECTX	SCTP_SOCKOPT_CONNECTX
 };
 
 /*
@@ -559,11 +563,16 @@ struct sctp_status {
  * SCTP_GET_LOCAL_ADDRS socket options used internally to implement
  * sctp_getpaddrs() and sctp_getladdrs() API. 
  */
-struct sctp_getaddrs {
+struct sctp_getaddrs_old {
 	sctp_assoc_t            assoc_id;
 	int			addr_num;
 	struct sockaddr		__user *addrs;
 };
+struct sctp_getaddrs {
+	sctp_assoc_t		assoc_id; /*input*/
+	__u32			addr_num; /*output*/
+	__u8			addrs[0]; /*output, variable size*/
+};
 
 /* These are bit fields for msghdr->msg_flags.  See section 5.1.  */
 /* On user space Linux, these live in <bits/socket.h> as an enum.  */