Index: head/sys/net/ethernet.h
===================================================================
--- head/sys/net/ethernet.h
+++ head/sys/net/ethernet.h
@@ -344,6 +344,7 @@
 #define	ETHERTYPE_PPPOE		0x8864	/* PPP Over Ethernet Session Stage */
 #define	ETHERTYPE_LANPROBE	0x8888	/* HP LanProbe test? */
 #define	ETHERTYPE_PAE		0x888e	/* EAPOL PAE/802.1x */
+#define	ETHERTYPE_QINQ		0x88A8	/* 802.1ad VLAN stacking */
 #define	ETHERTYPE_LOOPBACK	0x9000	/* Loopback: used to test interfaces */
 #define	ETHERTYPE_LBACK		ETHERTYPE_LOOPBACK	/* DEC MOP loopback */
 #define	ETHERTYPE_XNSSM		0x9001	/* 3Com (Formerly Bridge Communications), XNS Systems Management */