Moved NUM_SOCKETS and struct lwip_sock to sockets_priv.h; added test case for fd_use count with select

src/include/lwip/priv/sockets_priv.h

@@ -48,6 +48,48 @@
 extern "C" {
 #endif
 
+#define NUM_SOCKETS MEMP_NUM_NETCONN
+
+/** This is overridable for the rare case where more than 255 threads
+ * select on the same socket...
+ */
+#ifndef SELWAIT_T
+#define SELWAIT_T u8_t
+#endif
+
+union lwip_sock_lastdata {
+  struct netbuf *netbuf;
+  struct pbuf *pbuf;
+};
+
+/** Contains all internal pointers and states used for a socket */
+struct lwip_sock {
+  /** sockets currently are built on netconns, each socket has one netconn */
+  struct netconn *conn;
+  /** data that was left from the previous read */
+  union lwip_sock_lastdata lastdata;
+#if LWIP_SOCKET_SELECT
+  /** number of times data was received, set by event_callback(),
+      tested by the receive and select functions */
+  s16_t rcvevent;
+  /** number of times data was ACKed (free send buffer), set by event_callback(),
+      tested by select */
+  u16_t sendevent;
+  /** error happened for this socket, set by event_callback(), tested by select */
+  u16_t errevent;
+  /** counter of how many threads are waiting for this socket using select */
+  SELWAIT_T select_waiting;
+#endif /* LWIP_SOCKET_SELECT */
+#if LWIP_NETCONN_FULLDUPLEX
+  /* counter of how many threads are using a struct lwip_sock (not the 'int') */
+  u8_t fd_used;
+  /* status of pending close/delete actions */
+  u8_t fd_free_pending;
+#define LWIP_SOCK_FD_FREE_TCP  1
+#define LWIP_SOCK_FD_FREE_FREE 2
+#endif
+};
+
 #if LWIP_SOCKET_SET_ERRNO
 #ifndef set_errno
 #define set_errno(err) do { if (err) { errno = (err); } } while(0)
@@ -92,6 +134,8 @@ struct lwip_setgetsockopt_data {
 }
 #endif
 
+struct lwip_sock* lwip_socket_dbg_get_socket(int fd);
+
 #endif /* LWIP_SOCKET */
 
 #endif /* LWIP_HDR_SOCKETS_PRIV_H */