diff --git a/sys/compat/linux/linux_socket.c b/sys/compat/linux/linux_socket.c
index bb4af573f321..0b6c51a29423 100644
--- a/sys/compat/linux/linux_socket.c
+++ b/sys/compat/linux/linux_socket.c
@@ -236,6 +236,8 @@ linux_to_bsd_so_sockopt(int opt)
 		return (SO_TIMESTAMP);
 	case LINUX_SO_ACCEPTCONN:
 		return (SO_ACCEPTCONN);
+	case LINUX_SO_PROTOCOL:
+		return (SO_PROTOCOL);
 	}
 	return (-1);
 }
diff --git a/sys/compat/linux/linux_socket.h b/sys/compat/linux/linux_socket.h
index 82008e09dcef..88ecfb819133 100644
--- a/sys/compat/linux/linux_socket.h
+++ b/sys/compat/linux/linux_socket.h
@@ -197,6 +197,7 @@ int linux_accept(struct thread *td, struct linux_accept_args *args);
 #define	LINUX_SO_ACCEPTCONN	30
 #define	LINUX_SO_SNDBUFFORCE	32
 #define	LINUX_SO_RCVBUFFORCE	33
+#define	LINUX_SO_PROTOCOL	38
 
 /* Socket options */
 #define	LINUX_IP_TOS		1