diff --git a/sys/net80211/ieee80211_adhoc.c b/sys/net80211/ieee80211_adhoc.c
index 35bc345320b..8d9bcce5890 100644
--- a/sys/net80211/ieee80211_adhoc.c
+++ b/sys/net80211/ieee80211_adhoc.c
@@ -285,7 +285,6 @@ doprint(struct ieee80211vap *vap, int subtype)
 static int
 adhoc_input(struct ieee80211_node *ni, struct mbuf *m, int rssi, int nf)
 {
-#define	SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
 #define	HAS_SEQ(type)	((type & 0x4) == 0)
 	struct ieee80211vap *vap = ni->ni_vap;
 	struct ieee80211com *ic = ni->ni_ic;
@@ -412,9 +411,7 @@ adhoc_input(struct ieee80211_node *ni, struct mbuf *m, int rssi, int nf)
 			    TID_TO_WME_AC(tid) >= WME_AC_VI)
 				ic->ic_wme.wme_hipri_traffic++;
 			rxseq = le16toh(*(uint16_t *)wh->i_seq);
-			if ((ni->ni_flags & IEEE80211_NODE_HT) == 0 &&
-			    (wh->i_fc[1] & IEEE80211_FC1_RETRY) &&
-			    SEQ_LEQ(rxseq, ni->ni_rxseqs[tid])) {
+			if (! ieee80211_check_rxseq(ni, wh)) {
 				/* duplicate, discard */
 				IEEE80211_DISCARD_MAC(vap, IEEE80211_MSG_INPUT,
 				    bssid, "duplicate",
@@ -660,7 +657,6 @@ out:
 		m_freem(m);
 	}
 	return type;
-#undef SEQ_LEQ
 }
 
 static int
diff --git a/sys/net80211/ieee80211_hostap.c b/sys/net80211/ieee80211_hostap.c
index e3e14921c26..e1904500374 100644
--- a/sys/net80211/ieee80211_hostap.c
+++ b/sys/net80211/ieee80211_hostap.c
@@ -472,7 +472,6 @@ doprint(struct ieee80211vap *vap, int subtype)
 static int
 hostap_input(struct ieee80211_node *ni, struct mbuf *m, int rssi, int nf)
 {
-#define	SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
 #define	HAS_SEQ(type)	((type & 0x4) == 0)
 	struct ieee80211vap *vap = ni->ni_vap;
 	struct ieee80211com *ic = ni->ni_ic;
@@ -572,9 +571,7 @@ hostap_input(struct ieee80211_node *ni, struct mbuf *m, int rssi, int nf)
 			    TID_TO_WME_AC(tid) >= WME_AC_VI)
 				ic->ic_wme.wme_hipri_traffic++;
 			rxseq = le16toh(*(uint16_t *)wh->i_seq);
-			if ((ni->ni_flags & IEEE80211_NODE_HT) == 0 &&
-			    (wh->i_fc[1] & IEEE80211_FC1_RETRY) &&
-			    SEQ_LEQ(rxseq, ni->ni_rxseqs[tid])) {
+			if (! ieee80211_check_rxseq(ni, wh)) {
 				/* duplicate, discard */
 				IEEE80211_DISCARD_MAC(vap, IEEE80211_MSG_INPUT,
 				    bssid, "duplicate",
@@ -914,7 +911,6 @@ out:
 		m_freem(m);
 	}
 	return type;
-#undef SEQ_LEQ
 }
 
 static void
diff --git a/sys/net80211/ieee80211_input.h b/sys/net80211/ieee80211_input.h
index 5b38dddc6b5..b90f46a14a1 100644
--- a/sys/net80211/ieee80211_input.h
+++ b/sys/net80211/ieee80211_input.h
@@ -142,6 +142,104 @@ ishtinfooui(const uint8_t *frm)
 	return frm[1] > 3 && LE_READ_4(frm+2) == ((BCM_OUI_HTINFO<<24)|BCM_OUI);
 }
 
+#include <sys/endian.h>		/* For le16toh() */
+
+/*
+ * Check the current frame sequence number against the current TID
+ * state and return whether it's in sequence or should be dropped.
+ *
+ * Since out of order packet and duplicate packet eliminations should
+ * be done by the AMPDU RX code, this routine blindly accepts all
+ * frames from a HT station w/ a TID that is currently doing AMPDU-RX.
+ * HT stations without WME or where the TID is not doing AMPDU-RX
+ * are checked like non-HT stations.
+ *
+ * The routine only eliminates packets whose sequence/fragment
+ * match or are less than the last seen sequence/fragment number
+ * AND are retransmits It doesn't try to eliminate out of order packets.
+ *
+ * Since all frames after sequence number 4095 will be less than 4095
+ * (as the seqnum wraps), handle that special case so packets aren't
+ * incorrectly dropped - ie, if the next packet is sequence number 0
+ * but a retransmit since the initial packet didn't make it.
+ */
+static __inline int
+ieee80211_check_rxseq(struct ieee80211_node *ni, struct ieee80211_frame *wh)
+{
+#define	SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
+#define	SEQ_EQ(a,b)	((int)((a)-(b)) == 0)
+#define	HAS_SEQ(type)	((type & 0x4) == 0)
+#define	SEQNO(a)	((a) >> IEEE80211_SEQ_SEQ_SHIFT)
+#define	FRAGNO(a)	((a) & IEEE80211_SEQ_FRAG_MASK)
+	uint16_t rxseq;
+	uint8_t type;
+	uint8_t tid;
+	struct ieee80211_rx_ampdu *rap;
+
+	rxseq = le16toh(*(uint16_t *)wh->i_seq);
+	type = wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK;
+
+	/* Types with no sequence number are always treated valid */
+	if (! HAS_SEQ(type))
+		return 1;
+
+	tid = ieee80211_gettid(wh);
+
+	/*
+	 * Only do the HT AMPDU check for WME stations; non-WME HT stations
+	 * shouldn't exist outside of debugging. We should at least
+	 * handle that.
+	 */
+	if (tid < WME_NUM_TID) {
+		rap = &ni->ni_rx_ampdu[tid];
+		/* HT nodes currently doing RX AMPDU are always valid */
+		if ((ni->ni_flags & IEEE80211_NODE_HT) &&
+		    (rap->rxa_flags & IEEE80211_AGGR_RUNNING))
+			return 1;
+	}
+
+	/*	
+	 * Otherwise, retries for packets below or equal to the last
+	 * seen sequence number should be dropped.
+	 */
+
+	/*
+	 * Treat frame seqnum 4095 as special due to boundary
+	 * wrapping conditions.
+	 */
+	if (SEQNO(ni->ni_rxseqs[tid]) == 4095) {
+		/*
+		 * Drop retransmits on seqnum 4095/current fragment for itself.
+		 */
+		if (SEQ_EQ(rxseq, ni->ni_rxseqs[tid]) &&
+		    (wh->i_fc[1] & IEEE80211_FC1_RETRY))
+			return 0;
+		/*
+		 * Treat any subsequent frame as fine if the last seen frame
+		 * is 4095 and it's not a retransmit for the same sequence
+		 * number. However, this doesn't capture incorrectly ordered
+	 	 * fragments w/ sequence number 4095. It shouldn't be seen
+		 * in practice, but see the comment above for further info.
+		 */
+		return 1;
+	}
+
+	/*
+	 * At this point we assume that retransmitted seq/frag numbers below
+	 * the current can simply be eliminated.
+	 */
+	if ((wh->i_fc[1] & IEEE80211_FC1_RETRY) &&
+	    SEQ_LEQ(rxseq, ni->ni_rxseqs[tid]))
+		return 0;
+
+	return 1;
+#undef	SEQ_LEQ
+#undef	SEQ_EQ
+#undef	HAS_SEQ
+#undef	SEQNO
+#undef	FRAGNO
+}
+
 void	ieee80211_deliver_data(struct ieee80211vap *,
 		struct ieee80211_node *, struct mbuf *);
 struct mbuf *ieee80211_defrag(struct ieee80211_node *,
diff --git a/sys/net80211/ieee80211_mesh.c b/sys/net80211/ieee80211_mesh.c
index 4cf2aac6f0c..571a7335390 100644
--- a/sys/net80211/ieee80211_mesh.c
+++ b/sys/net80211/ieee80211_mesh.c
@@ -1040,7 +1040,6 @@ mesh_isucastforme(struct ieee80211vap *vap, const struct ieee80211_frame *wh,
 static int
 mesh_input(struct ieee80211_node *ni, struct mbuf *m, int rssi, int nf)
 {
-#define	SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
 #define	HAS_SEQ(type)	((type & 0x4) == 0)
 	struct ieee80211vap *vap = ni->ni_vap;
 	struct ieee80211com *ic = ni->ni_ic;
@@ -1094,9 +1093,7 @@ mesh_input(struct ieee80211_node *ni, struct mbuf *m, int rssi, int nf)
 			    TID_TO_WME_AC(tid) >= WME_AC_VI)
 				ic->ic_wme.wme_hipri_traffic++;
 			rxseq = le16toh(*(uint16_t *)wh->i_seq);
-			if ((ni->ni_flags & IEEE80211_NODE_HT) == 0 &&
-			    (wh->i_fc[1] & IEEE80211_FC1_RETRY) &&
-			    SEQ_LEQ(rxseq, ni->ni_rxseqs[tid])) {
+			if (! ieee80211_check_rxseq(ni, wh)) {
 				/* duplicate, discard */
 				IEEE80211_DISCARD_MAC(vap, IEEE80211_MSG_INPUT,
 				    wh->i_addr1, "duplicate",
diff --git a/sys/net80211/ieee80211_sta.c b/sys/net80211/ieee80211_sta.c
index f8d488af3b4..5444459a152 100644
--- a/sys/net80211/ieee80211_sta.c
+++ b/sys/net80211/ieee80211_sta.c
@@ -512,7 +512,6 @@ doprint(struct ieee80211vap *vap, int subtype)
 static int
 sta_input(struct ieee80211_node *ni, struct mbuf *m, int rssi, int nf)
 {
-#define	SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
 #define	HAS_SEQ(type)	((type & 0x4) == 0)
 	struct ieee80211vap *vap = ni->ni_vap;
 	struct ieee80211com *ic = ni->ni_ic;
@@ -591,9 +590,7 @@ sta_input(struct ieee80211_node *ni, struct mbuf *m, int rssi, int nf)
 			    TID_TO_WME_AC(tid) >= WME_AC_VI)
 				ic->ic_wme.wme_hipri_traffic++;
 			rxseq = le16toh(*(uint16_t *)wh->i_seq);
-			if ((ni->ni_flags & IEEE80211_NODE_HT) == 0 &&
-			    (wh->i_fc[1] & IEEE80211_FC1_RETRY) &&
-			    SEQ_LEQ(rxseq, ni->ni_rxseqs[tid])) {
+			if (! ieee80211_check_rxseq(ni, wh)) {
 				/* duplicate, discard */
 				IEEE80211_DISCARD_MAC(vap, IEEE80211_MSG_INPUT,
 				    bssid, "duplicate",
@@ -910,7 +907,6 @@ out:
 		m_freem(m);
 	}
 	return type;
-#undef SEQ_LEQ
 }
 
 static void
diff --git a/sys/net80211/ieee80211_wds.c b/sys/net80211/ieee80211_wds.c
index 926ef578bd1..ed82fac1c08 100644
--- a/sys/net80211/ieee80211_wds.c
+++ b/sys/net80211/ieee80211_wds.c
@@ -406,7 +406,6 @@ wds_newstate(struct ieee80211vap *vap, enum ieee80211_state nstate, int arg)
 static int
 wds_input(struct ieee80211_node *ni, struct mbuf *m, int rssi, int nf)
 {
-#define	SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
 #define	HAS_SEQ(type)	((type & 0x4) == 0)
 	struct ieee80211vap *vap = ni->ni_vap;
 	struct ieee80211com *ic = ni->ni_ic;
@@ -495,9 +494,7 @@ wds_input(struct ieee80211_node *ni, struct mbuf *m, int rssi, int nf)
 		    TID_TO_WME_AC(tid) >= WME_AC_VI)
 			ic->ic_wme.wme_hipri_traffic++;
 		rxseq = le16toh(*(uint16_t *)wh->i_seq);
-		if ((ni->ni_flags & IEEE80211_NODE_HT) == 0 &&
-		    (wh->i_fc[1] & IEEE80211_FC1_RETRY) &&
-		    SEQ_LEQ(rxseq, ni->ni_rxseqs[tid])) {
+		if (! ieee80211_check_rxseq(ni, wh)) {
 			/* duplicate, discard */
 			IEEE80211_DISCARD_MAC(vap, IEEE80211_MSG_INPUT,
 			    wh->i_addr1, "duplicate",
@@ -741,7 +738,6 @@ out:
 		m_freem(m);
 	}
 	return type;
-#undef SEQ_LEQ
 }
 
 static void