tipc: Add socket options to get number of queued messages

This patch allows a TIPC application to determine the number of messages
currently waiting in a socket's receive queue (TIPC_SOCK_RECVQ_DEPTH) or
in all TIPC socket receive queues (TIPC_NODE_RECVQ_DEPTH).
Signed-off-by: Oscar Medina <oscar.medina@motorola.com>
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/tipc.h

@@ -209,5 +209,7 @@ struct sockaddr_tipc {
 #define TIPC_SRC_DROPPABLE	128	/* Default: 0 (resend congested msg) */
 #define TIPC_DEST_DROPPABLE	129	/* Default: based on socket type */
 #define TIPC_CONN_TIMEOUT	130	/* Default: 8000 (ms)  */
+#define TIPC_NODE_RECVQ_DEPTH	131	/* Default: none (read only) */
+#define TIPC_SOCK_RECVQ_DEPTH	132	/* Default: none (read only) */
 
 #endif

net/tipc/socket.c

@@ -1748,6 +1748,12 @@ static int getsockopt(struct socket *sock,
 		value = jiffies_to_msecs(sk->sk_rcvtimeo);
 		/* no need to set "res", since already 0 at this point */
 		break;
+	 case TIPC_NODE_RECVQ_DEPTH:
+		value = (u32)atomic_read(&tipc_queue_size);
+		break;
+	 case TIPC_SOCK_RECVQ_DEPTH:
+		value = skb_queue_len(&sk->sk_receive_queue);
+		break;
 	default:
 		res = -EINVAL;
 	}