datapath-windows/NetlinkBuf.h: Added NlBufSize

Added an inline function to return used size in the buffer.

Signed-off-by: Ankur Sharma <ankursharma@vmware.com>
Acked-by: Nithin Raju <nithin@vmware.com>
Acked-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>

datapath-windows/ovsext/Netlink/NetlinkBuf.h

@@ -38,4 +38,18 @@ PCHAR NlBufCopyAtOffsetUninit(PNL_BUFFER nlBuf, UINT32 len, UINT32 offset);
 
 PCHAR NlBufAt(PNL_BUFFER nlBuf, UINT32 offset, UINT32 len);
 
+/*
+ * --------------------------------------------------------------------------
+ * NlBufSize --
+ *
+ *    Returns the used size of buffer.
+ * --------------------------------------------------------------------------
+ */
+static __inline UINT32
+NlBufSize(PNL_BUFFER nlBuf)
+{
+    ASSERT(nlBuf);
+    return (nlBuf->bufLen - nlBuf->bufRemLen);
+}
+
 #endif /* __NETLINK_BUF_H_ */