Index: sys/compat/linux/linux_socket.h
===================================================================
--- sys/compat/linux/linux_socket.h
+++ sys/compat/linux/linux_socket.h
@@ -236,6 +236,7 @@
 
 #define	LINUX_TCP_NODELAY	1
 #define	LINUX_TCP_MAXSEG	2
+#define	LINUX_TCP_CORK		3
 #define	LINUX_TCP_KEEPIDLE	4
 #define	LINUX_TCP_KEEPINTVL	5
 #define	LINUX_TCP_KEEPCNT	6
Index: sys/compat/linux/linux_socket.c
===================================================================
--- sys/compat/linux/linux_socket.c
+++ sys/compat/linux/linux_socket.c
@@ -240,6 +240,7 @@
 
 	switch (opt) {
 	case LINUX_TCP_NODELAY:
+	case LINUX_TCP_CORK:
 		return (TCP_NODELAY);
 	case LINUX_TCP_MAXSEG:
 		return (TCP_MAXSEG);