Index: head/sys/netinet/tcp_input.c
===================================================================
--- head/sys/netinet/tcp_input.c
+++ head/sys/netinet/tcp_input.c
@@ -1028,7 +1028,7 @@
 #endif
 	if (!((tp->t_state == TCPS_ESTABLISHED && (thflags & TH_SYN) == 0) ||
 	      (tp->t_state == TCPS_LISTEN && (thflags & TH_SYN) &&
-	       !(tp->t_flags & TF_FASTOPEN)))) {
+	       !IS_FASTOPEN(tp->t_flags)))) {
 		if (ti_locked == TI_UNLOCKED) {
 			if (INP_INFO_TRY_RLOCK(&V_tcbinfo) == 0) {
 				in_pcbref(inp);
@@ -1506,7 +1506,9 @@
 	struct in_conninfo *inc;
 	struct mbuf *mfree;
 	struct tcpopt to;
+#ifdef TCP_RFC7413
 	int tfo_syn;
+#endif
 	
 #ifdef TCPDEBUG
 	/*
@@ -1964,7 +1966,7 @@
 				goto dropwithreset;
 		}
 #ifdef TCP_RFC7413
-		if (tp->t_flags & TF_FASTOPEN) {
+		if (IS_FASTOPEN(tp->t_flags)) {
 			/*
 			 * When a TFO connection is in SYN_RECEIVED, the
 			 * only valid packets are the initial SYN, a
@@ -2398,7 +2400,7 @@
 		    (tp->t_flags & TF_NEEDSYN)) {
 #ifdef TCP_RFC7413
 			if (tp->t_state == TCPS_SYN_RECEIVED &&
-			    tp->t_flags & TF_FASTOPEN) {
+			    IS_FASTOPEN(tp->t_flags)) {
 				tp->snd_wnd = tiwin;
 				cc_conn_init(tp);
 			}
@@ -2461,7 +2463,7 @@
 			 * snd_cwnd reduction that occurs when a TFO SYN|ACK
 			 * is retransmitted.
 			 */
-			if (!(tp->t_flags & TF_FASTOPEN))
+			if (!IS_FASTOPEN(tp->t_flags))
 #endif
 				cc_conn_init(tp);
 			tcp_timer_activate(tp, TT_KEEP, TP_KEEPIDLE(tp));
@@ -3028,8 +3030,12 @@
 	 * case PRU_RCVD).  If a FIN has already been received on this
 	 * connection then we just ignore the text.
 	 */
+#ifdef TCP_RFC7413
 	tfo_syn = ((tp->t_state == TCPS_SYN_RECEIVED) &&
-		   (tp->t_flags & TF_FASTOPEN));
+		   IS_FASTOPEN(tp->t_flags));
+#else
+#define	tfo_syn	(false)
+#endif
 	if ((tlen || (thflags & TH_FIN) || tfo_syn) &&
 	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
 		tcp_seq save_start = th->th_seq;
@@ -3253,6 +3259,9 @@
 	if (tp != NULL)
 		INP_WUNLOCK(tp->t_inpcb);
 	m_freem(m);
+#ifndef TCP_RFC7413
+#undef	tfo_syn
+#endif
 }
 
 /*
Index: head/sys/netinet/tcp_output.c
===================================================================
--- head/sys/netinet/tcp_output.c
+++ head/sys/netinet/tcp_output.c
@@ -230,7 +230,7 @@
 	 * For TFO connections in SYN_RECEIVED, only allow the initial
 	 * SYN|ACK and those sent by the retransmit timer.
 	 */
-	if ((tp->t_flags & TF_FASTOPEN) &&
+	if (IS_FASTOPEN(tp->t_flags) &&
 	    (tp->t_state == TCPS_SYN_RECEIVED) &&
 	    SEQ_GT(tp->snd_max, tp->snd_una) &&    /* initial SYN|ACK sent */
 	    (tp->snd_nxt != tp->snd_una))          /* not a retransmit */
@@ -426,7 +426,7 @@
 		 * When sending additional segments following a TFO SYN|ACK,
 		 * do not include the SYN bit.
 		 */
-		if ((tp->t_flags & TF_FASTOPEN) &&
+		if (IS_FASTOPEN(tp->t_flags) &&
 		    (tp->t_state == TCPS_SYN_RECEIVED))
 			flags &= ~TH_SYN;
 #endif
@@ -449,7 +449,7 @@
 	 * don't include data, as the presence of data may have caused the
 	 * original SYN|ACK to have been dropped by a middlebox.
 	 */
-	if ((tp->t_flags & TF_FASTOPEN) &&
+	if (IS_FASTOPEN(tp->t_flags) &&
 	    (((tp->t_state == TCPS_SYN_RECEIVED) && (tp->t_rxtshift > 0)) ||
 	     (flags & TH_RST)))
 		len = 0;
@@ -786,7 +786,7 @@
 			 * the TFO option may have caused the original
 			 * SYN|ACK to have been dropped by a middlebox.
 			 */
-			if ((tp->t_flags & TF_FASTOPEN) &&
+			if (IS_FASTOPEN(tp->t_flags) &&
 			    (tp->t_state == TCPS_SYN_RECEIVED) &&
 			    (tp->t_rxtshift == 0)) {
 				to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN;
Index: head/sys/netinet/tcp_syncache.c
===================================================================
--- head/sys/netinet/tcp_syncache.c
+++ head/sys/netinet/tcp_syncache.c
@@ -1209,7 +1209,7 @@
 	ltflags = (tp->t_flags & (TF_NOOPT | TF_SIGNATURE));
 
 #ifdef TCP_RFC7413
-	if (V_tcp_fastopen_enabled && (tp->t_flags & TF_FASTOPEN) &&
+	if (V_tcp_fastopen_enabled && IS_FASTOPEN(tp->t_flags) &&
 	    (tp->t_tfo_pending != NULL) && (to->to_flags & TOF_FASTOPEN)) {
 		/*
 		 * Limit the number of pending TFO connections to
Index: head/sys/netinet/tcp_usrreq.c
===================================================================
--- head/sys/netinet/tcp_usrreq.c
+++ head/sys/netinet/tcp_usrreq.c
@@ -410,7 +410,7 @@
 	SOCK_UNLOCK(so);
 
 #ifdef TCP_RFC7413
-	if (tp->t_flags & TF_FASTOPEN)
+	if (IS_FASTOPEN(tp->t_flags))
 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
 #endif
 out:
@@ -460,7 +460,7 @@
 	SOCK_UNLOCK(so);
 
 #ifdef TCP_RFC7413
-	if (tp->t_flags & TF_FASTOPEN)
+	if (IS_FASTOPEN(tp->t_flags))
 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
 #endif
 out:
@@ -826,7 +826,7 @@
 	 * application response data, or failing that, when the DELACK timer
 	 * expires.
 	 */
-	if ((tp->t_flags & TF_FASTOPEN) &&
+	if (IS_FASTOPEN(tp->t_flags) &&
 	    (tp->t_state == TCPS_SYN_RECEIVED))
 		goto out;
 #endif
Index: head/sys/netinet/tcp_var.h
===================================================================
--- head/sys/netinet/tcp_var.h
+++ head/sys/netinet/tcp_var.h
@@ -349,6 +349,12 @@
 #define	ENTER_RECOVERY(t_flags) t_flags |= (TF_CONGRECOVERY | TF_FASTRECOVERY)
 #define	EXIT_RECOVERY(t_flags) t_flags &= ~(TF_CONGRECOVERY | TF_FASTRECOVERY)
 
+#if defined(_KERNEL) && !defined(TCP_RFC7413)
+#define	IS_FASTOPEN(t_flags)		(false)
+#else
+#define	IS_FASTOPEN(t_flags)		(t_flags & TF_FASTOPEN)
+#endif
+
 #define	BYTES_THIS_ACK(tp, th)	(th->th_ack - tp->snd_una)
 
 /*