diff --git a/packets.h b/packets.h
index 6f4ae26..e16b80b 100644
--- a/packets.h
+++ b/packets.h
@@ -1,5 +1,6 @@
 #include <stdint.h>
 #include <stdlib.h>
+#include <sys/types.h>
 
 #define IS_UNKNOWN 0
 #define IS_HTTP 1