diff --git a/sys/netinet/in_pcb.c b/sys/netinet/in_pcb.c
index 3d40b9fcc56..131b99854d9 100644
--- a/sys/netinet/in_pcb.c
+++ b/sys/netinet/in_pcb.c
@@ -62,6 +62,8 @@
 #include <netinet/in_pcb.h>
 #include <netinet/in_var.h>
 #include <netinet/ip_var.h>
+#include <netinet/tcp.h>
+#include <netinet/tcp_var.h>
 #ifdef INET6
 #include <netinet/ip6.h>
 #include <netinet6/ip6_var.h>