diff --git a/echo.cpp b/echo.cpp
index e464d30..5ae9173 100644
--- a/echo.cpp
+++ b/echo.cpp
@@ -21,9 +21,11 @@
 #include "exception.h"
 
 #include <sys/socket.h>
+#include <netinet/in_systm.h>
 #include <netinet/in.h>
 #include <netinet/ip.h>
 #include <arpa/inet.h>
+#include <unistd.h>
 
 typedef ip IpHeader;
 
diff --git a/tun.cpp b/tun.cpp
index c91ccf9..4c95680 100644
--- a/tun.cpp
+++ b/tun.cpp
@@ -22,6 +22,8 @@
 #include "utility.h"
 
 #include <arpa/inet.h>
+#include <netinet/in_systm.h>
+#include <netinet/in.h>
 #include <netinet/ip.h>
 #include <syslog.h>
 #include <stdlib.h>
diff --git a/worker.cpp b/worker.cpp
index 42ec83f..407dea7 100644
--- a/worker.cpp
+++ b/worker.cpp
@@ -24,6 +24,7 @@
 
 #include <string.h>
 #include <syslog.h>
+#include <unistd.h>
 
 using namespace std;