Index: sys/kern/uipc_mbuf.c
===================================================================
--- sys/kern/uipc_mbuf.c
+++ sys/kern/uipc_mbuf.c
@@ -111,11 +111,11 @@
  */
 #if defined(__LP64__)
 CTASSERT(offsetof(struct mbuf, m_dat) == 32);
-CTASSERT(sizeof(struct pkthdr) == 56);
+CTASSERT(sizeof(struct pkthdr) == 64);
 CTASSERT(sizeof(struct m_ext) == 48);
 #else
 CTASSERT(offsetof(struct mbuf, m_dat) == 24);
-CTASSERT(sizeof(struct pkthdr) == 48);
+CTASSERT(sizeof(struct pkthdr) == 52);
 CTASSERT(sizeof(struct m_ext) == 28);
 #endif
 
Index: sys/sys/mbuf.h
===================================================================
--- sys/sys/mbuf.h
+++ sys/sys/mbuf.h
@@ -105,13 +105,14 @@
 
 /*
  * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
- * Size ILP32: 48
- *	 LP64: 56
+ * Size ILP32: 52
+ *	 LP64: 64
  * Compile-time assertions in uipc_mbuf.c test these values to ensure that
  * they are correct.
  */
 struct pkthdr {
 	struct ifnet	*rcvif;		/* rcv interface */
+	struct ifring	*ifring;	/* rcv ring */
 	SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
 	int32_t		 len;		/* total packet length */