Add bip_get_socket (#210)

* Add function to get BIP socket

* Add bip_get_socket to all applicable ports

ports/bsd/bip-init.c

@@ -80,6 +80,15 @@ static void debug_print_ipv4(const char *str,
     }
 }
 
+/**
+ * @brief Return the active BIP socket.
+ * @return The active BIP socket, or -1 if uninitialized.
+ */
+int bip_get_socket(void)
+{
+    return BIP_Socket;
+}
+
 /**
  * @brief Enabled debug printing of BACnet/IPv4
  */

ports/linux/bip-init.c

@@ -94,6 +94,17 @@ static void debug_print_ipv4(const char *str,
     }
 }
 
+
+/**
+ * @brief Return the active BIP socket.
+ * @return The active BIP socket, or -1 if uninitialized.
+ */
+int bip_get_socket(void)
+{
+    return BIP_Socket;
+}
+
+
 /**
  * @brief Enabled debug printing of BACnet/IPv4
  */

ports/win32/bip-init.c

@@ -87,6 +87,17 @@ static void debug_print_ipv4(const char *str,
     }
 }
 
+/**
+ * @brief Return the active BIP socket.
+ * @return The active BIP socket, or INVALID_SOCKET if uninitialized.
+ * @note Strictly, the return type should be SOCKET, however in practice 
+ *  Windows never returns values large enough that truncation is an issue.
+ */
+int bip_get_socket(void)
+{
+    return (int)BIP_Socket;
+}
+
 /**
  * @brief Enabled debug printing of BACnet/IPv4
  */

src/bacnet/datalink/bip.h

@@ -115,6 +115,9 @@ extern "C" {
     BACNET_STACK_EXPORT
     void bip_debug_enable(void);
 
+    BACNET_STACK_EXPORT
+    int bip_get_socket(void);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */