net: Add functions to return connection status needed in TCP

These are internal functions needed when initiating a TCP
connection.

Change-Id: Ide5d59ac9854ec8bdea3baa97b3cde3ffa6a5e0f
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>

include/net/net_core.h

@@ -143,6 +143,19 @@ int net_recv(struct net_buf *buf);
 
 void net_context_init(void);
 
+/**
+ * @brief Get current status of the TCP connection.
+ *
+ * @details Application can call this to get the current status
+ * of TCP connection. The returned value maps to errno values.
+ * Value 0 means ok. For UDP context 0 is always returned.
+ *
+ * @param context Network context
+ *
+ * @return 0 if ok, < 0 connection status
+ */
+int net_context_get_connection_status(struct net_context *context);
+
 #ifdef __cplusplus
 }
 #endif