diff --git a/src/relay/udp.cpp b/src/relay/udp.cpp
index 8af2bc9b..e072bbee 100644
--- a/src/relay/udp.cpp
+++ b/src/relay/udp.cpp
@@ -3,6 +3,7 @@
 
 #include <algorithm>
 #include <cstring>
+#include <ctime>
 #include <memory>
 
 #include <sodium.h>