diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -1680,7 +1680,7 @@
 		    (tp->t_flags & TF_NOOPT))) {
 			tp->t_flags &= ~TF_SACK_PERMIT;
 		}
-		if (IS_FASTOPEN(tp->t_flags)) {
+		if (tp->t_flags & TF_FASTOPEN) {
 			if ((to.to_flags & TOF_FASTOPEN) &&
 			    !(tp->t_flags & TF_NOOPT)) {
 				uint16_t mss;
@@ -1989,7 +1989,7 @@
 				tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
 				goto dropwithreset;
 		}
-		if (IS_FASTOPEN(tp->t_flags)) {
+		if (tp->t_flags & TF_FASTOPEN) {
 			/*
 			 * When a TFO connection is in SYN_RECEIVED, the
 			 * only valid packets are the initial SYN, a
@@ -2063,7 +2063,7 @@
 			 * If not all the data that was sent in the TFO SYN
 			 * has been acked, resend the remainder right away.
 			 */
-			if (IS_FASTOPEN(tp->t_flags) &&
+			if ((tp->t_flags & TF_FASTOPEN) &&
 			    (tp->snd_una != tp->snd_max)) {
 				tp->snd_nxt = th->th_ack;
 				tfo_partial_ack = 1;
@@ -2419,7 +2419,7 @@
 		if (tp->t_state == TCPS_SYN_RECEIVED ||
 		    (tp->t_flags & TF_NEEDSYN)) {
 			if (tp->t_state == TCPS_SYN_RECEIVED &&
-			    IS_FASTOPEN(tp->t_flags)) {
+			    (tp->t_flags & TF_FASTOPEN)) {
 				tp->snd_wnd = tiwin;
 				cc_conn_init(tp);
 			}
@@ -2467,7 +2467,7 @@
 		 *      SYN-RECEIVED* -> FIN-WAIT-1
 		 */
 		tp->t_starttime = ticks;
-		if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
+		if ((tp->t_flags & TF_FASTOPEN) && tp->t_tfo_pending) {
 			tcp_fastopen_decrement_counter(tp->t_tfo_pending);
 			tp->t_tfo_pending = NULL;
 		}
@@ -2486,7 +2486,7 @@
 			 * snd_cwnd reduction that occurs when a TFO SYN|ACK
 			 * is retransmitted.
 			 */
-			if (!IS_FASTOPEN(tp->t_flags))
+			if (!(tp->t_flags & TF_FASTOPEN))
 				cc_conn_init(tp);
 			tcp_timer_activate(tp, TT_KEEP, TP_KEEPIDLE(tp));
 		}
@@ -3167,7 +3167,7 @@
 	 * connection then we just ignore the text.
 	 */
 	tfo_syn = ((tp->t_state == TCPS_SYN_RECEIVED) &&
-		   IS_FASTOPEN(tp->t_flags));
+	    (tp->t_flags & TF_FASTOPEN));
 	if ((tlen || (thflags & TH_FIN) || (tfo_syn && tlen > 0)) &&
 	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
 		tcp_seq save_start = th->th_seq;
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -239,10 +239,10 @@
 	 * only allow the initial SYN or SYN|ACK and those sent
 	 * by the retransmit timer.
 	 */
-	if (IS_FASTOPEN(tp->t_flags) &&
+	if ((tp->t_flags & TF_FASTOPEN) &&
 	    ((tp->t_state == TCPS_SYN_SENT) ||
-	     (tp->t_state == TCPS_SYN_RECEIVED)) &&
-	    SEQ_GT(tp->snd_max, tp->snd_una) && /* initial SYN or SYN|ACK sent */
+	    (tp->t_state == TCPS_SYN_RECEIVED)) &&
+	    SEQ_GT(tp->snd_max, tp->snd_una) && /* SYN or SYN|ACK sent */
 	    (tp->snd_nxt != tp->snd_una))       /* not a retransmit */
 		return (0);
 
@@ -436,7 +436,7 @@
 		 * When sending additional segments following a TFO SYN|ACK,
 		 * do not include the SYN bit.
 		 */
-		if (IS_FASTOPEN(tp->t_flags) &&
+		if ((tp->t_flags & TF_FASTOPEN) &&
 		    (tp->t_state == TCPS_SYN_RECEIVED))
 			flags &= ~TH_SYN;
 		off--, len++;
@@ -464,7 +464,7 @@
 	 *
 	 *  - When the socket is in the CLOSED state (RST is being sent)
 	 */
-	if (IS_FASTOPEN(tp->t_flags) &&
+	if ((tp->t_flags & TF_FASTOPEN) &&
 	    (((flags & TH_SYN) && (tp->t_rxtshift > 0)) ||
 	     ((tp->t_state == TCPS_SYN_SENT) &&
 	      (tp->t_tfo_client_cookie_len == 0)) ||
@@ -801,7 +801,7 @@
 			 * have caused the original SYN or SYN|ACK to have
 			 * been dropped by a middlebox.
 			 */
-			if (IS_FASTOPEN(tp->t_flags) &&
+			if ((tp->t_flags & TF_FASTOPEN) &&
 			    (tp->t_rxtshift == 0)) {
 				if (tp->t_state == TCPS_SYN_RECEIVED) {
 					to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN;
@@ -875,7 +875,7 @@
 		 * If we wanted a TFO option to be added, but it was unable
 		 * to fit, ensure no data is sent.
 		 */
-		if (IS_FASTOPEN(tp->t_flags) && wanted_cookie &&
+		if ((tp->t_flags & TF_FASTOPEN) && wanted_cookie &&
 		    !(to.to_flags & TOF_FASTOPEN))
 			len = 0;
 	}
diff --git a/sys/netinet/tcp_stacks/bbr.c b/sys/netinet/tcp_stacks/bbr.c
--- a/sys/netinet/tcp_stacks/bbr.c
+++ b/sys/netinet/tcp_stacks/bbr.c
@@ -8188,7 +8188,7 @@
 	 * then we just ignore the text.
 	 */
 	tfo_syn = ((tp->t_state == TCPS_SYN_RECEIVED) &&
-		   IS_FASTOPEN(tp->t_flags));
+	    (tp->t_flags & TF_FASTOPEN));
 	if ((tlen || (thflags & TH_FIN) || (tfo_syn && tlen > 0)) &&
 	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
 		tcp_seq save_start = th->th_seq;
@@ -8773,7 +8773,7 @@
 		 * If not all the data that was sent in the TFO SYN
 		 * has been acked, resend the remainder right away.
 		 */
-		if (IS_FASTOPEN(tp->t_flags) &&
+		if ((tp->t_flags & TF_FASTOPEN) &&
 		    (tp->snd_una != tp->snd_max)) {
 			tp->snd_nxt = th->th_ack;
 			tfo_partial = 1;
@@ -8939,7 +8939,7 @@
 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
 		return (1);
 	}
-	if (IS_FASTOPEN(tp->t_flags)) {
+	if (tp->t_flags & TF_FASTOPEN) {
 		/*
 		 * When a TFO connection is in SYN_RECEIVED, the only valid
 		 * packets are the initial SYN, a retransmit/copy of the
@@ -9015,7 +9015,7 @@
 	 * processing; else drop segment and return.
 	 */
 	if ((thflags & TH_ACK) == 0) {
-		if (IS_FASTOPEN(tp->t_flags)) {
+		if (tp->t_flags & TF_FASTOPEN) {
 			cc_conn_init(tp);
 		}
 		return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
@@ -9052,7 +9052,7 @@
 	/* Drop off any SYN in the send map (probably not there)  */
 	if (thflags & TH_ACK)
 		bbr_log_syn(tp, to);
-	if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
+	if ((tp->t_flags & TF_FASTOPEN) && tp->t_tfo_pending) {
 		tcp_fastopen_decrement_counter(tp->t_tfo_pending);
 		tp->t_tfo_pending = NULL;
 	}
@@ -9074,7 +9074,7 @@
 		 * is not harmless as it would undo the snd_cwnd reduction
 		 * that occurs when a TFO SYN|ACK is retransmitted.
 		 */
-		if (!IS_FASTOPEN(tp->t_flags))
+		if (!(tp->t_flags & TF_FASTOPEN))
 			cc_conn_init(tp);
 	}
 	/*
@@ -11408,7 +11408,7 @@
 			if ((tp->t_flags & TF_SACK_PERMIT) &&
 			    (to.to_flags & TOF_SACKPERM) == 0)
 				tp->t_flags &= ~TF_SACK_PERMIT;
-			if (IS_FASTOPEN(tp->t_flags)) {
+			if (tp->t_flags & TF_FASTOPEN) {
 				if (to.to_flags & TOF_FASTOPEN) {
 					uint16_t mss;
 
@@ -12062,7 +12062,7 @@
 	 * For TFO connections in SYN_RECEIVED, only allow the initial
 	 * SYN|ACK and those sent by the retransmit timer.
 	 */
-	if (IS_FASTOPEN(tp->t_flags) &&
+	if ((tp->t_flags & TF_FASTOPEN) &&
 	    ((tp->t_state == TCPS_SYN_RECEIVED) ||
 	     (tp->t_state == TCPS_SYN_SENT)) &&
 	    SEQ_GT(tp->snd_max, tp->snd_una) &&	/* initial SYN or SYN|ACK sent */
@@ -12381,7 +12381,7 @@
 		 * When sending additional segments following a TFO SYN|ACK,
 		 * do not include the SYN bit.
 		 */
-		if (IS_FASTOPEN(tp->t_flags) &&
+		if ((tp->t_flags & TF_FASTOPEN) &&
 		    (tp->t_state == TCPS_SYN_RECEIVED))
 			flags &= ~TH_SYN;
 		sb_offset--, len++;
@@ -12412,7 +12412,7 @@
 	 *    actively created socket
 	 *  - When the socket is in the CLOSED state (RST is being sent)
 	 */
-	if (IS_FASTOPEN(tp->t_flags) &&
+	if ((tp->t_flags & TF_FASTOPEN) &&
 	    (((flags & TH_SYN) && (tp->t_rxtshift > 0)) ||
 	     ((tp->t_state == TCPS_SYN_SENT) &&
 	      (tp->t_tfo_client_cookie_len == 0)) ||
@@ -12422,7 +12422,7 @@
 		rsm = NULL;
 	}
 	/* Without fast-open there should never be data sent on a SYN */
-	if ((flags & TH_SYN) && (!IS_FASTOPEN(tp->t_flags)))
+	if ((flags & TH_SYN) && !(tp->t_flags & TF_FASTOPEN))
 		len = 0;
 	if (len <= 0) {
 		/*
@@ -12846,7 +12846,7 @@
 			 * have caused the original SYN or SYN|ACK to have
 			 * been dropped by a middlebox.
 			 */
-			if (IS_FASTOPEN(tp->t_flags) &&
+			if ((tp->t_flags & TF_FASTOPEN) &&
 			    (tp->t_rxtshift == 0)) {
 				if (tp->t_state == TCPS_SYN_RECEIVED) {
 					to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN;
@@ -12902,7 +12902,7 @@
 		 * If we wanted a TFO option to be added, but it was unable
 		 * to fit, ensure no data is sent.
 		 */
-		if (IS_FASTOPEN(tp->t_flags) && wanted_cookie &&
+		if ((tp->t_flags & TF_FASTOPEN) && wanted_cookie &&
 		    !(to.to_flags & TOF_FASTOPEN))
 			len = 0;
 	}
diff --git a/sys/netinet/tcp_stacks/rack.c b/sys/netinet/tcp_stacks/rack.c
--- a/sys/netinet/tcp_stacks/rack.c
+++ b/sys/netinet/tcp_stacks/rack.c
@@ -13585,7 +13585,7 @@
 	 * then we just ignore the text.
 	 */
 	tfo_syn = ((tp->t_state == TCPS_SYN_RECEIVED) &&
-		   IS_FASTOPEN(tp->t_flags));
+	    (tp->t_flags & TF_FASTOPEN));
 	if ((tlen || (thflags & TH_FIN) || (tfo_syn && tlen > 0)) &&
 	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
 		tcp_seq save_start = th->th_seq;
@@ -14194,7 +14194,7 @@
 		 * If not all the data that was sent in the TFO SYN
 		 * has been acked, resend the remainder right away.
 		 */
-		if (IS_FASTOPEN(tp->t_flags) &&
+		if ((tp->t_flags & TF_FASTOPEN) &&
 		    (tp->snd_una != tp->snd_max)) {
 			/* Was it a partial ack? */
 			if (SEQ_LT(th->th_ack, tp->snd_max))
@@ -14373,7 +14373,7 @@
 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
 		return (1);
 	}
-	if (IS_FASTOPEN(tp->t_flags)) {
+	if (tp->t_flags & TF_FASTOPEN) {
 		/*
 		 * When a TFO connection is in SYN_RECEIVED, the
 		 * only valid packets are the initial SYN, a
@@ -14454,7 +14454,7 @@
 	 * processing; else drop segment and return.
 	 */
 	if ((thflags & TH_ACK) == 0) {
-		if (IS_FASTOPEN(tp->t_flags)) {
+		if (tp->t_flags & TF_FASTOPEN) {
 			rack_cc_conn_init(tp);
 		}
 		return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
@@ -14475,7 +14475,7 @@
 	 * FIN-WAIT-1
 	 */
 	tp->t_starttime = ticks;
-	if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
+	if ((tp->t_flags & TF_FASTOPEN) && tp->t_tfo_pending) {
 		tcp_fastopen_decrement_counter(tp->t_tfo_pending);
 		tp->t_tfo_pending = NULL;
 	}
@@ -14492,7 +14492,7 @@
 		 * is not harmless as it would undo the snd_cwnd reduction
 		 * that occurs when a TFO SYN|ACK is retransmitted.
 		 */
-		if (!IS_FASTOPEN(tp->t_flags))
+		if (!(tp->t_flags & TF_FASTOPEN))
 			rack_cc_conn_init(tp);
 	}
 	/*
@@ -18198,7 +18198,7 @@
 			if ((tp->t_flags & TF_SACK_PERMIT) &&
 			    (to.to_flags & TOF_SACKPERM) == 0)
 				tp->t_flags &= ~TF_SACK_PERMIT;
-			if (IS_FASTOPEN(tp->t_flags)) {
+			if (tp->t_flags & TF_FASTOPEN) {
 				if (to.to_flags & TOF_FASTOPEN) {
 					uint16_t mss;
 
@@ -21346,7 +21346,7 @@
 	 * For TFO connections in SYN_RECEIVED, only allow the initial
 	 * SYN|ACK and those sent by the retransmit timer.
 	 */
-	if (IS_FASTOPEN(tp->t_flags) &&
+	if ((tp->t_flags & TF_FASTOPEN) &&
 	    (tp->t_state == TCPS_SYN_RECEIVED) &&
 	    SEQ_GT(tp->snd_max, tp->snd_una) &&    /* initial SYN|ACK sent */
 	    (rack->r_ctl.rc_resend == NULL)) {         /* not a retransmit */
@@ -21494,7 +21494,7 @@
 	 * only allow the initial SYN or SYN|ACK and those sent
 	 * by the retransmit timer.
 	 */
-	if (IS_FASTOPEN(tp->t_flags) &&
+	if ((tp->t_flags & TF_FASTOPEN) &&
 	    ((tp->t_state == TCPS_SYN_RECEIVED) ||
 	     (tp->t_state == TCPS_SYN_SENT)) &&
 	    SEQ_GT(tp->snd_max, tp->snd_una) && /* initial SYN or SYN|ACK sent */
@@ -21949,7 +21949,8 @@
 	}
 	SOCKBUF_LOCK(sb);
 	if ((sack_rxmit == 0) &&
-	    (TCPS_HAVEESTABLISHED(tp->t_state) || IS_FASTOPEN(tp->t_flags))) {
+	    (TCPS_HAVEESTABLISHED(tp->t_state) ||
+	    (tp->t_flags & TF_FASTOPEN))) {
 		/*
 		 * We are not retransmitting (sack_rxmit is 0) so we
 		 * are sending new data. This is always based on snd_max.
@@ -22075,7 +22076,7 @@
 		 * no data please.
 		 */
 		if ((sack_rxmit == 0) &&
-		    (!IS_FASTOPEN(tp->t_flags))){
+		    !(tp->t_flags & TF_FASTOPEN)) {
 			len = 0;
 			sb_offset = 0;
 		}
@@ -22135,7 +22136,7 @@
 		 * When sending additional segments following a TFO SYN|ACK,
 		 * do not include the SYN bit.
 		 */
-		if (IS_FASTOPEN(tp->t_flags) &&
+		if ((tp->t_flags & TF_FASTOPEN) &&
 		    (tp->t_state == TCPS_SYN_RECEIVED))
 			flags &= ~TH_SYN;
 	}
@@ -22160,7 +22161,7 @@
 	 *
 	 *  - When the socket is in the CLOSED state (RST is being sent)
 	 */
-	if (IS_FASTOPEN(tp->t_flags) &&
+	if ((tp->t_flags & TF_FASTOPEN) &&
 	    (((flags & TH_SYN) && (tp->t_rxtshift > 0)) ||
 	     ((tp->t_state == TCPS_SYN_SENT) &&
 	      (tp->t_tfo_client_cookie_len == 0)) ||
@@ -22169,7 +22170,7 @@
 		len = 0;
 	}
 	/* Without fast-open there should never be data sent on a SYN */
-	if ((flags & TH_SYN) && (!IS_FASTOPEN(tp->t_flags))) {
+	if ((flags & TH_SYN) && !(tp->t_flags & TF_FASTOPEN)) {
 		len = 0;
 	}
 	if ((len > segsiz) && (tcp_dsack_block_exists(tp))) {
@@ -22498,7 +22499,7 @@
 	{
 		int app_limited = CTF_JR_SENT_DATA;
 
-		if ((IS_FASTOPEN(tp->t_flags) == 0) &&
+		if ((tp->t_flags & TF_FASTOPEN) == 0 &&
 		    (flags & TH_FIN) &&
 		    (len == 0) &&
 		    (sbused(sb) == (tp->snd_max - tp->snd_una)) &&
@@ -22866,7 +22867,7 @@
 			 * have caused the original SYN or SYN|ACK to have
 			 * been dropped by a middlebox.
 			 */
-			if (IS_FASTOPEN(tp->t_flags) &&
+			if ((tp->t_flags & TF_FASTOPEN) &&
 			    (tp->t_rxtshift == 0)) {
 				if (tp->t_state == TCPS_SYN_RECEIVED) {
 					to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN;
@@ -22964,7 +22965,7 @@
 		 * If we wanted a TFO option to be added, but it was unable
 		 * to fit, ensure no data is sent.
 		 */
-		if (IS_FASTOPEN(tp->t_flags) && wanted_cookie &&
+		if ((tp->t_flags & TF_FASTOPEN) && wanted_cookie &&
 		    !(to.to_flags & TOF_FASTOPEN))
 			len = 0;
 	}
diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -3282,7 +3282,7 @@
 	if (tp->t_state != TCPS_SYN_SENT)
 		return (inp);
 
-	if (IS_FASTOPEN(tp->t_flags))
+	if (tp->t_flags & TF_FASTOPEN)
 		tcp_fastopen_disable_path(tp);
 
 	tp = tcp_drop(tp, errno);
diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c
--- a/sys/netinet/tcp_syncache.c
+++ b/sys/netinet/tcp_syncache.c
@@ -1447,7 +1447,7 @@
 	win = so->sol_sbrcv_hiwat;
 	ltflags = (tp->t_flags & (TF_NOOPT | TF_SIGNATURE));
 
-	if (V_tcp_fastopen_server_enable && IS_FASTOPEN(tp->t_flags) &&
+	if (V_tcp_fastopen_server_enable && (tp->t_flags & TF_FASTOPEN) &&
 	    (tp->t_tfo_pending != NULL) &&
 	    (to->to_flags & TOF_FASTOPEN)) {
 		/*
diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -397,7 +397,7 @@
 	}
 	SOCK_UNLOCK(so);
 
-	if (IS_FASTOPEN(tp->t_flags))
+	if (tp->t_flags & TF_FASTOPEN)
 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
 
 out:
@@ -454,7 +454,7 @@
 	}
 	SOCK_UNLOCK(so);
 
-	if (IS_FASTOPEN(tp->t_flags))
+	if (tp->t_flags & TF_FASTOPEN)
 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
 
 	if (error != 0)
@@ -887,8 +887,7 @@
 	 * application response data, or failing that, when the DELACK timer
 	 * expires.
 	 */
-	if (IS_FASTOPEN(tp->t_flags) &&
-	    (tp->t_state == TCPS_SYN_RECEIVED))
+	if ((tp->t_flags & TF_FASTOPEN) && (tp->t_state == TCPS_SYN_RECEIVED))
 		goto out;
 #ifdef TCP_OFFLOAD
 	if (tp->t_flags & TF_TOE)
@@ -1095,7 +1094,7 @@
 				sbflush(&so->so_snd);
 				goto out;
 			}
-			if (IS_FASTOPEN(tp->t_flags))
+			if (tp->t_flags & TF_FASTOPEN)
 				tcp_fastopen_connect(tp);
 			else {
 				tp->snd_wnd = TTCP_CLIENT_SND_WND;
@@ -1161,7 +1160,7 @@
 			/*
 			 * Not going to contemplate SYN|URG
 			 */
-			if (IS_FASTOPEN(tp->t_flags))
+			if (tp->t_flags & TF_FASTOPEN)
 				tp->t_flags &= ~TF_FASTOPEN;
 #ifdef INET6
 			if (isipv6)
@@ -1578,7 +1577,7 @@
 		default:
 			break;
 	}
-	if (IS_FASTOPEN(tp->t_flags))
+	if (tp->t_flags & TF_FASTOPEN)
 		ti->tcpi_options |= TCPI_OPT_TFO;
 
 	ti->tcpi_rto = tp->t_rxtcur * tick;
@@ -2685,7 +2684,7 @@
 	 * socket is still open.
 	 */
 	if (tp->t_state < TCPS_ESTABLISHED &&
-	    !(tp->t_state > TCPS_LISTEN && IS_FASTOPEN(tp->t_flags))) {
+	    !(tp->t_state > TCPS_LISTEN && (tp->t_flags & TF_FASTOPEN))) {
 		tp = tcp_close(tp);
 		KASSERT(tp != NULL,
 		    ("tcp_disconnect: tcp_close() returned NULL"));
diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -812,14 +812,6 @@
 #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)
-#if !defined(TCP_RFC7413)
-#define	IS_FASTOPEN(t_flags)		(false)
-#else
-#define	IS_FASTOPEN(t_flags)		(t_flags & TF_FASTOPEN)
-#endif
-#endif
-
 #define	BYTES_THIS_ACK(tp, th)	(th->th_ack - tp->snd_una)
 
 /*