diff --git a/p2p/base/port.cc b/p2p/base/port.cc
index a1b478d116..81aa0aadb8 100644
--- a/p2p/base/port.cc
+++ b/p2p/base/port.cc
@@ -10,6 +10,8 @@
 
 #include "p2p/base/port.h"
 
+#include <math.h>
+
 #include <algorithm>
 #include <vector>