diff --git a/common/rfb/util.cxx b/common/rfb/util.cxx
index 265114f..2709f2c 100644
--- a/common/rfb/util.cxx
+++ b/common/rfb/util.cxx
@@ -34,6 +34,8 @@
 #include <config.h>
 #endif
 
+#include <sys/time.h>
+
 #include <rfb/util.h>
 
 // Provide strcasecmp() and/or strncasecmp() if absent on this system.
@@ -185,4 +187,18 @@
     dest[src ? destlen-1 : 0] = 0;
   }
 
+  unsigned msSince(const struct timeval *then)
+  {
+    struct timeval now;
+    unsigned diff;
+
+    gettimeofday(&now, NULL);
+
+    diff = (now.tv_sec - then->tv_sec) * 1000;
+
+    diff += now.tv_usec / 1000;
+    diff -= then->tv_usec / 1000;
+
+    return diff;
+  }
 };
diff --git a/common/rfb/util.h b/common/rfb/util.h
index 4124769..7d90a6b 100644
--- a/common/rfb/util.h
+++ b/common/rfb/util.h
@@ -30,6 +30,8 @@
 #include <limits.h>
 #include <string.h>
 
+struct timeval;
+
 namespace rfb {
 
   // -=- Class to handle cleanup of arrays of characters
@@ -85,6 +87,9 @@
   inline int secsToMillis(int secs) {
     return (secs < 0 || secs > (INT_MAX/1000) ? INT_MAX : secs * 1000);
   }
+
+  // Returns time elapsed since given moment in milliseconds.
+  unsigned msSince(const struct timeval *then);
 }
 
 // Some platforms (e.g. Windows) include max() and min() macros in their