diff --git a/src/protocol.c b/src/protocol.c
index 3caccb6a3..7884ef734 100644
--- a/src/protocol.c
+++ b/src/protocol.c
@@ -10,6 +10,7 @@
  *
  */
 
+#include <sys/types.h>
 #include <sys/socket.h>
 
 #include <common/config.h>