Index: head/sys/amd64/conf/GENERIC
===================================================================
--- head/sys/amd64/conf/GENERIC
+++ head/sys/amd64/conf/GENERIC
@@ -33,6 +33,7 @@
 options 	IPSEC_SUPPORT		# Allow kldload of ipsec and tcpmd5
 options 	TCP_OFFLOAD		# TCP offload
 options 	TCP_HHOOK		# hhook(9) framework for TCP
+options		TCP_RFC7413		# TCP Fast Open
 options 	SCTP			# Stream Control Transmission Protocol
 options 	FFS			# Berkeley Fast Filesystem
 options 	SOFTUPDATES		# Enable FFS soft updates support
Index: head/sys/arm64/conf/GENERIC
===================================================================
--- head/sys/arm64/conf/GENERIC
+++ head/sys/arm64/conf/GENERIC
@@ -33,6 +33,7 @@
 options 	IPSEC_SUPPORT		# Allow kldload of ipsec and tcpmd5
 options 	TCP_HHOOK		# hhook(9) framework for TCP
 options 	TCP_OFFLOAD		# TCP offload
+options		TCP_RFC7413		# TCP Fast Open
 options 	SCTP			# Stream Control Transmission Protocol
 options 	FFS			# Berkeley Fast Filesystem
 options 	SOFTUPDATES		# Enable FFS soft updates support
Index: head/sys/netinet/tcp_fastopen.h
===================================================================
--- head/sys/netinet/tcp_fastopen.h
+++ head/sys/netinet/tcp_fastopen.h
@@ -31,13 +31,20 @@
 
 #ifdef _KERNEL
 
+#include "opt_inet.h"
+
 #define	TCP_FASTOPEN_COOKIE_LEN		8	/* SipHash24 64-bit output */
 
+#ifdef TCP_RFC7413
 VNET_DECLARE(unsigned int, tcp_fastopen_client_enable);
 #define	V_tcp_fastopen_client_enable	VNET(tcp_fastopen_client_enable)
 
 VNET_DECLARE(unsigned int, tcp_fastopen_server_enable);
 #define	V_tcp_fastopen_server_enable	VNET(tcp_fastopen_server_enable)
+#else
+#define	V_tcp_fastopen_client_enable	0
+#define	V_tcp_fastopen_server_enable	0
+#endif  /* TCP_RFC7413 */
 
 union tcp_fastopen_ip_addr {
 	struct in_addr v4;
@@ -74,6 +81,7 @@
 	uint32_t 	secret;
 };
 
+#ifdef TCP_RFC7413
 void	tcp_fastopen_init(void);
 void	tcp_fastopen_destroy(void);
 unsigned int *tcp_fastopen_alloc_counter(void);
@@ -84,6 +92,17 @@
 void	tcp_fastopen_disable_path(struct tcpcb *);
 void	tcp_fastopen_update_cache(struct tcpcb *, uint16_t, uint8_t,
 	    uint8_t *);
+#else
+#define tcp_fastopen_init()			((void)0)
+#define tcp_fastopen_destroy()			((void)0)
+#define tcp_fastopen_alloc_counter()		NULL
+#define tcp_fastopen_decrement_counter(c)	((void)0)
+#define tcp_fastopen_check_cookie(i, c, l, lc)	(-1)
+#define tcp_fastopen_connect(t)			((void)0)
+#define tcp_fastopen_disable_path(t)		((void)0)
+#define tcp_fastopen_update_cache(t, m, l, c)	((void)0)
+#endif /* TCP_RFC7413 */
+
 #endif /* _KERNEL */
 
 #endif /* _TCP_FASTOPEN_H_ */
Index: head/sys/netinet/tcp_input.c
===================================================================
--- head/sys/netinet/tcp_input.c
+++ head/sys/netinet/tcp_input.c
@@ -108,9 +108,7 @@
 #include <netinet6/tcp6_var.h>
 #include <netinet/tcpip.h>
 #include <netinet/cc/cc.h>
-#ifdef TCP_RFC7413
 #include <netinet/tcp_fastopen.h>
-#endif
 #ifdef TCPPCAP
 #include <netinet/tcp_pcap.h>
 #endif
@@ -1130,9 +1128,7 @@
 				rstreason = BANDLIM_RST_OPENPORT;
 				goto dropwithreset;
 			}
-#ifdef TCP_RFC7413
 tfo_socket_result:
-#endif
 			if (so == NULL) {
 				/*
 				 * We completed the 3-way handshake
@@ -1375,12 +1371,9 @@
 #endif
 		TCP_PROBE3(debug__input, tp, th, m);
 		tcp_dooptions(&to, optp, optlen, TO_SYN);
-#ifdef TCP_RFC7413
 		if (syncache_add(&inc, &to, th, inp, &so, m, NULL, NULL))
 			goto tfo_socket_result;
-#else
-		syncache_add(&inc, &to, th, inp, &so, m, NULL, NULL);
-#endif
+
 		/*
 		 * Entry added to syncache and mbuf consumed.
 		 * Only the listen socket is unlocked by syncache_add().
@@ -1550,9 +1543,7 @@
 	struct in_conninfo *inc;
 	struct mbuf *mfree;
 	struct tcpopt to;
-#ifdef TCP_RFC7413
 	int tfo_syn;
-#endif
 	
 #ifdef TCPDEBUG
 	/*
@@ -1717,7 +1708,6 @@
 		if ((tp->t_flags & TF_SACK_PERMIT) &&
 		    (to.to_flags & TOF_SACKPERM) == 0)
 			tp->t_flags &= ~TF_SACK_PERMIT;
-#ifdef TCP_RFC7413
 		if (IS_FASTOPEN(tp->t_flags)) {
 			if (to.to_flags & TOF_FASTOPEN)
 				tcp_fastopen_update_cache(tp, to.to_mss,
@@ -1725,7 +1715,6 @@
 			else
 				tcp_fastopen_disable_path(tp);
 		}
-#endif
 	}
 
 	/*
@@ -1983,7 +1972,6 @@
 				rstreason = BANDLIM_RST_OPENPORT;
 				goto dropwithreset;
 		}
-#ifdef TCP_RFC7413
 		if (IS_FASTOPEN(tp->t_flags)) {
 			/*
 			 * When a TFO connection is in SYN_RECEIVED, the
@@ -2004,7 +1992,6 @@
 				goto drop;
 			}
 		}
-#endif
 		break;
 
 	/*
@@ -2423,13 +2410,11 @@
 	if ((thflags & TH_ACK) == 0) {
 		if (tp->t_state == TCPS_SYN_RECEIVED ||
 		    (tp->t_flags & TF_NEEDSYN)) {
-#ifdef TCP_RFC7413
 			if (tp->t_state == TCPS_SYN_RECEIVED &&
 			    IS_FASTOPEN(tp->t_flags)) {
 				tp->snd_wnd = tiwin;
 				cc_conn_init(tp);
 			}
-#endif
 			goto step6;
 		} else if (tp->t_flags & TF_ACKNOW)
 			goto dropafterack;
@@ -2470,8 +2455,7 @@
 			tcp_state_change(tp, TCPS_ESTABLISHED);
 			TCP_PROBE5(accept__established, NULL, tp,
 			    m, tp, th);
-#ifdef TCP_RFC7413
-			if (tp->t_tfo_pending) {
+			if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
 				tcp_fastopen_decrement_counter(tp->t_tfo_pending);
 				tp->t_tfo_pending = NULL;
 
@@ -2489,7 +2473,6 @@
 			 * is retransmitted.
 			 */
 			if (!IS_FASTOPEN(tp->t_flags))
-#endif
 				cc_conn_init(tp);
 			tcp_timer_activate(tp, TT_KEEP, TP_KEEPIDLE(tp));
 		}
@@ -3055,12 +3038,8 @@
 	 * 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) &&
 		   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;
@@ -3284,9 +3263,6 @@
 	if (tp != NULL)
 		INP_WUNLOCK(tp->t_inpcb);
 	m_freem(m);
-#ifndef TCP_RFC7413
-#undef	tfo_syn
-#endif
 }
 
 /*
@@ -3440,7 +3416,6 @@
 			to->to_sacks = cp + 2;
 			TCPSTAT_INC(tcps_sack_rcv_blocks);
 			break;
-#ifdef TCP_RFC7413
 		case TCPOPT_FAST_OPEN:
 			/*
 			 * Cookie length validation is performed by the
@@ -3456,7 +3431,6 @@
 			to->to_tfo_len = optlen - 2;
 			to->to_tfo_cookie = to->to_tfo_len ? cp + 2 : NULL;
 			break;
-#endif
 		default:
 			continue;
 		}
Index: head/sys/netinet/tcp_output.c
===================================================================
--- head/sys/netinet/tcp_output.c
+++ head/sys/netinet/tcp_output.c
@@ -79,9 +79,7 @@
 #include <netinet/tcp_var.h>
 #include <netinet/tcpip.h>
 #include <netinet/cc/cc.h>
-#ifdef TCP_RFC7413
 #include <netinet/tcp_fastopen.h>
-#endif
 #ifdef TCPPCAP
 #include <netinet/tcp_pcap.h>
 #endif
@@ -212,10 +210,8 @@
 	struct sackhole *p;
 	int tso, mtu;
 	struct tcpopt to;
-#ifdef TCP_RFC7413
 	unsigned int wanted_cookie = 0;
 	unsigned int dont_sendalot = 0;
-#endif
 #if 0
 	int maxburst = TCP_MAXBURST;
 #endif
@@ -233,7 +229,6 @@
 		return (tcp_offload_output(tp));
 #endif
 
-#ifdef TCP_RFC7413
 	/*
 	 * For TFO connections in SYN_RECEIVED, only allow the initial
 	 * SYN|ACK and those sent by the retransmit timer.
@@ -243,7 +238,7 @@
 	    SEQ_GT(tp->snd_max, tp->snd_una) &&    /* initial SYN|ACK sent */
 	    (tp->snd_nxt != tp->snd_una))         /* not a retransmit */
 		return (0);
-#endif
+
 	/*
 	 * Determine length of data that should be transmitted,
 	 * and flags that will be used.
@@ -429,7 +424,6 @@
 	if ((flags & TH_SYN) && SEQ_GT(tp->snd_nxt, tp->snd_una)) {
 		if (tp->t_state != TCPS_SYN_RECEIVED)
 			flags &= ~TH_SYN;
-#ifdef TCP_RFC7413
 		/*
 		 * When sending additional segments following a TFO SYN|ACK,
 		 * do not include the SYN bit.
@@ -437,7 +431,6 @@
 		if (IS_FASTOPEN(tp->t_flags) &&
 		    (tp->t_state == TCPS_SYN_RECEIVED))
 			flags &= ~TH_SYN;
-#endif
 		off--, len++;
 	}
 
@@ -451,7 +444,6 @@
 		flags &= ~TH_FIN;
 	}
 
-#ifdef TCP_RFC7413
 	/*
 	 * On TFO sockets, ensure no data is sent in the following cases:
 	 *
@@ -470,7 +462,6 @@
 	      (tp->t_tfo_client_cookie_len == 0)) ||
 	     (flags & TH_RST)))
 		len = 0;
-#endif
 	if (len <= 0) {
 		/*
 		 * If FIN has been sent but not acked,
@@ -774,7 +765,7 @@
 			tp->snd_nxt = tp->iss;
 			to.to_mss = tcp_mssopt(&tp->t_inpcb->inp_inc);
 			to.to_flags |= TOF_MSS;
-#ifdef TCP_RFC7413
+
 			/*
 			 * On SYN or SYN|ACK transmits on TFO connections,
 			 * only include the TFO option if it is not a
@@ -807,7 +798,6 @@
 					dont_sendalot = 1;
 				}
 			}
-#endif
 		}
 		/* Window scaling. */
 		if ((flags & TH_SYN) && (tp->t_flags & TF_REQ_SCALE)) {
@@ -851,7 +841,6 @@
 
 		/* Processing the options. */
 		hdrlen += optlen = tcp_addoptions(&to, opt);
-#ifdef TCP_RFC7413
 		/*
 		 * If we wanted a TFO option to be added, but it was unable
 		 * to fit, ensure no data is sent.
@@ -859,7 +848,6 @@
 		if (IS_FASTOPEN(tp->t_flags) && wanted_cookie &&
 		    !(to.to_flags & TOF_FASTOPEN))
 			len = 0;
-#endif
 	}
 
 	/*
@@ -1004,10 +992,8 @@
 		} else {
 			len = tp->t_maxseg - optlen - ipoptlen;
 			sendalot = 1;
-#ifdef TCP_RFC7413
 			if (dont_sendalot)
 				sendalot = 0;
-#endif
 		}
 	} else
 		tso = 0;
@@ -1811,7 +1797,6 @@
 			TCPSTAT_INC(tcps_sack_send_blocks);
 			break;
 			}
-#ifdef TCP_RFC7413
 		case TOF_FASTOPEN:
 			{
 			int total_len;
@@ -1831,7 +1816,6 @@
 			optlen += total_len;
 			break;
 			}
-#endif
 		default:
 			panic("%s: unknown TCP option type", __func__);
 			break;
Index: head/sys/netinet/tcp_subr.c
===================================================================
--- head/sys/netinet/tcp_subr.c
+++ head/sys/netinet/tcp_subr.c
@@ -104,9 +104,7 @@
 #include <netinet6/tcp6_var.h>
 #endif
 #include <netinet/tcpip.h>
-#ifdef TCP_RFC7413
 #include <netinet/tcp_fastopen.h>
-#endif
 #ifdef TCPPCAP
 #include <netinet/tcp_pcap.h>
 #endif
@@ -755,9 +753,7 @@
 	V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
 
-#ifdef TCP_RFC7413
 	tcp_fastopen_init();
-#endif
 
 	/* Skip initialization of globals for non-default instances. */
 	if (!IS_DEFAULT_VNET(curvnet))
@@ -844,13 +840,11 @@
 	uma_zdestroy(V_sack_hole_zone);
 	uma_zdestroy(V_tcpcb_zone);
 
-#ifdef TCP_RFC7413
 	/*
 	 * Cannot free the zone until all tcpcbs are released as we attach
 	 * the allocations to them.
 	 */
 	tcp_fastopen_destroy();
-#endif
 
 #ifdef TCP_HHOOK
 	error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_IN]);
@@ -1647,7 +1641,6 @@
 	if (tp->t_state == TCPS_LISTEN)
 		tcp_offload_listen_stop(tp);
 #endif
-#ifdef TCP_RFC7413
 	/*
 	 * This releases the TFO pending counter resource for TFO listen
 	 * sockets as well as passively-created TFO sockets that transition
@@ -1657,7 +1650,6 @@
 		tcp_fastopen_decrement_counter(tp->t_tfo_pending);
 		tp->t_tfo_pending = NULL;
 	}
-#endif
 	in_pcbdrop(inp);
 	TCPSTAT_INC(tcps_closed);
 	if (tp->t_state != TCPS_CLOSED)
@@ -2407,10 +2399,8 @@
 	if (tp->t_state != TCPS_SYN_SENT)
 		return (inp);
 
-#ifdef TCP_RFC7413
 	if (IS_FASTOPEN(tp->t_flags))
 		tcp_fastopen_disable_path(tp);
-#endif
 	
 	tp = tcp_drop(tp, errno);
 	if (tp != NULL)
Index: head/sys/netinet/tcp_syncache.h
===================================================================
--- head/sys/netinet/tcp_syncache.h
+++ head/sys/netinet/tcp_syncache.h
@@ -75,9 +75,7 @@
 #endif
 	struct label	*sc_label;		/* MAC label reference */
 	struct ucred	*sc_cred;		/* cred cache for jail checks */
-#ifdef TCP_RFC7413
 	void		*sc_tfo_cookie;		/* for TCP Fast Open response */
-#endif
 	void		*sc_pspare;		/* TCP_SIGNATURE */
 	u_int32_t	sc_spare[2];		/* UTO */
 };
Index: head/sys/netinet/tcp_syncache.c
===================================================================
--- head/sys/netinet/tcp_syncache.c
+++ head/sys/netinet/tcp_syncache.c
@@ -83,9 +83,7 @@
 #include <netinet6/in6_pcb.h>
 #endif
 #include <netinet/tcp.h>
-#ifdef TCP_RFC7413
 #include <netinet/tcp_fastopen.h>
-#endif
 #include <netinet/tcp_fsm.h>
 #include <netinet/tcp_seq.h>
 #include <netinet/tcp_timer.h>
@@ -1176,7 +1174,6 @@
 	return (0);
 }
 
-#ifdef TCP_RFC7413
 static void
 syncache_tfo_expand(struct syncache *sc, struct socket **lsop, struct mbuf *m,
     uint64_t response_cookie)
@@ -1208,7 +1205,6 @@
 		TCPSTAT_INC(tcps_sc_completed);
 	}
 }
-#endif /* TCP_RFC7413 */
 
 /*
  * Given a LISTEN socket and an inbound SYN request, add
@@ -1251,12 +1247,10 @@
 #endif
 	struct syncache scs;
 	struct ucred *cred;
-#ifdef TCP_RFC7413
 	uint64_t tfo_response_cookie;
 	unsigned int *tfo_pending = NULL;
 	int tfo_cookie_valid = 0;
 	int tfo_response_cookie_valid = 0;
-#endif
 
 	INP_WLOCK_ASSERT(inp);			/* listen socket */
 	KASSERT((th->th_flags & (TH_RST|TH_ACK|TH_SYN)) == TH_SYN,
@@ -1281,7 +1275,6 @@
 	win = so->sol_sbrcv_hiwat;
 	ltflags = (tp->t_flags & (TF_NOOPT | TF_SIGNATURE));
 
-#ifdef TCP_RFC7413
 	if (V_tcp_fastopen_server_enable && IS_FASTOPEN(tp->t_flags) &&
 	    (tp->t_tfo_pending != NULL) &&
 	    (to->to_flags & TOF_FASTOPEN)) {
@@ -1308,7 +1301,6 @@
 		 */
 		tfo_pending = tp->t_tfo_pending;
 	}
-#endif
 
 	/* By the time we drop the lock these should no longer be used. */
 	so = NULL;
@@ -1321,9 +1313,7 @@
 	} else
 		mac_syncache_create(maclabel, inp);
 #endif
-#ifdef TCP_RFC7413
 	if (!tfo_cookie_valid)
-#endif
 		INP_WUNLOCK(inp);
 
 	/*
@@ -1369,10 +1359,8 @@
 	sc = syncache_lookup(inc, &sch);	/* returns locked entry */
 	SCH_LOCK_ASSERT(sch);
 	if (sc != NULL) {
-#ifdef TCP_RFC7413
 		if (tfo_cookie_valid)
 			INP_WUNLOCK(inp);
-#endif
 		TCPSTAT_INC(tcps_sc_dupsyn);
 		if (ipopts) {
 			/*
@@ -1415,13 +1403,11 @@
 		goto done;
 	}
 
-#ifdef TCP_RFC7413
 	if (tfo_cookie_valid) {
 		bzero(&scs, sizeof(scs));
 		sc = &scs;
 		goto skip_alloc;
 	}
-#endif
 
 	sc = uma_zalloc(V_tcp_syncache.zone, M_NOWAIT | M_ZERO);
 	if (sc == NULL) {
@@ -1449,11 +1435,9 @@
 		}
 	}
 
-#ifdef TCP_RFC7413
 skip_alloc:
 	if (!tfo_cookie_valid && tfo_response_cookie_valid)
 		sc->sc_tfo_cookie = &tfo_response_cookie;
-#endif
 
 	/*
 	 * Fill in the syncache values.
@@ -1562,14 +1546,12 @@
 #endif
 	SCH_UNLOCK(sch);
 
-#ifdef TCP_RFC7413
 	if (tfo_cookie_valid) {
 		syncache_tfo_expand(sc, lsop, m, tfo_response_cookie);
 		/* INP_WUNLOCK(inp) will be performed by the caller */
 		rv = 1;
 		goto tfo_expanded;
 	}
-#endif
 
 	/*
 	 * Do a standard 3-way handshake.
@@ -1592,7 +1574,6 @@
 		*lsop = NULL;
 		m_freem(m);
 	}
-#ifdef TCP_RFC7413
 	/*
 	 * If tfo_pending is not NULL here, then a TFO SYN that did not
 	 * result in a new socket was processed and the associated pending
@@ -1603,7 +1584,6 @@
 		tcp_fastopen_decrement_counter(tfo_pending);
 
 tfo_expanded:
-#endif
 	if (cred != NULL)
 		crfree(cred);
 #ifdef MAC
@@ -1740,7 +1720,6 @@
 		if (sc->sc_flags & SCF_SIGNATURE)
 			to.to_flags |= TOF_SIGNATURE;
 #endif
-#ifdef TCP_RFC7413
 		if (sc->sc_tfo_cookie) {
 			to.to_flags |= TOF_FASTOPEN;
 			to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN;
@@ -1748,7 +1727,6 @@
 			/* don't send cookie again when retransmitting response */
 			sc->sc_tfo_cookie = NULL;
 		}
-#endif
 		optlen = tcp_addoptions(&to, (u_char *)(th + 1));
 
 		/* Adjust headers by option size. */
Index: head/sys/netinet/tcp_usrreq.c
===================================================================
--- head/sys/netinet/tcp_usrreq.c
+++ head/sys/netinet/tcp_usrreq.c
@@ -92,9 +92,7 @@
 #include <netinet/tcp_var.h>
 #include <netinet/tcpip.h>
 #include <netinet/cc/cc.h>
-#ifdef TCP_RFC7413
 #include <netinet/tcp_fastopen.h>
-#endif
 #ifdef TCPPCAP
 #include <netinet/tcp_pcap.h>
 #endif
@@ -430,10 +428,9 @@
 	}
 	SOCK_UNLOCK(so);
 
-#ifdef TCP_RFC7413
 	if (IS_FASTOPEN(tp->t_flags))
 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
-#endif
+
 out:
 	TCPDEBUG2(PRU_LISTEN);
 	TCP_PROBE2(debug__user, tp, PRU_LISTEN);
@@ -480,10 +477,9 @@
 	}
 	SOCK_UNLOCK(so);
 
-#ifdef TCP_RFC7413
 	if (IS_FASTOPEN(tp->t_flags))
 		tp->t_tfo_pending = tcp_fastopen_alloc_counter();
-#endif
+
 out:
 	TCPDEBUG2(PRU_LISTEN);
 	TCP_PROBE2(debug__user, tp, PRU_LISTEN);
@@ -848,7 +844,6 @@
 	}
 	tp = intotcpcb(inp);
 	TCPDEBUG1();
-#ifdef TCP_RFC7413
 	/*
 	 * For passively-created TFO connections, don't attempt a window
 	 * update while still in SYN_RECEIVED as this may trigger an early
@@ -859,7 +854,6 @@
 	if (IS_FASTOPEN(tp->t_flags) &&
 	    (tp->t_state == TCPS_SYN_RECEIVED))
 		goto out;
-#endif
 #ifdef TCP_OFFLOAD
 	if (tp->t_flags & TF_TOE)
 		tcp_offload_rcvd(tp);
@@ -950,12 +944,9 @@
 #endif
 			if (error)
 				goto out;
-#ifdef TCP_RFC7413
 			if (IS_FASTOPEN(tp->t_flags))
 				tcp_fastopen_connect(tp);
-			else
-#endif
-			{
+			else {
 				tp->snd_wnd = TTCP_CLIENT_SND_WND;
 				tcp_mss(tp, -1);
 			}
@@ -1004,13 +995,12 @@
 			 * initialize window to default value, and
 			 * initialize maxseg using peer's cached MSS.
 			 */
-#ifdef TCP_RFC7413
+
 			/*
 			 * Not going to contemplate SYN|URG
 			 */
 			if (IS_FASTOPEN(tp->t_flags))
 				tp->t_flags &= ~TF_FASTOPEN;
-#endif
 #ifdef INET6
 			if (isipv6)
 				error = tcp6_connect(tp, nam, td);
@@ -1782,7 +1772,6 @@
 			goto unlock_and_done;
 #endif
 
-#ifdef TCP_RFC7413
 		case TCP_FASTOPEN: {
 			struct tcp_fastopen tfo_optval;
 
@@ -1829,7 +1818,6 @@
 				tp->t_flags &= ~TF_FASTOPEN;
 			goto unlock_and_done;
 		}
-#endif
 
 		default:
 			INP_WUNLOCK(inp);
@@ -1911,14 +1899,11 @@
 			error = sooptcopyout(sopt, &optval, sizeof optval);
 			break;
 #endif
-
-#ifdef TCP_RFC7413
 		case TCP_FASTOPEN:
 			optval = tp->t_flags & TF_FASTOPEN;
 			INP_WUNLOCK(inp);
 			error = sooptcopyout(sopt, &optval, sizeof optval);
 			break;
-#endif
 		default:
 			INP_WUNLOCK(inp);
 			error = ENOPROTOOPT;
Index: head/sys/netinet/tcp_var.h
===================================================================
--- head/sys/netinet/tcp_var.h
+++ head/sys/netinet/tcp_var.h
@@ -191,14 +191,12 @@
 	u_int	t_flags2;		/* More tcpcb flags storage */
 	struct tcp_function_block *t_fb;/* TCP function call block */
 	void	*t_fb_ptr;		/* Pointer to t_fb specific data */
-#ifdef TCP_RFC7413
 	uint8_t t_tfo_client_cookie_len; /* TCP Fast Open client cookie length */
 	unsigned int *t_tfo_pending;	/* TCP Fast Open server pending counter */
 	union {
 		uint8_t client[TCP_FASTOPEN_MAX_COOKIE_LEN];
 		uint64_t server;
 	} t_tfo_cookie;			/* TCP Fast Open cookie to send */
-#endif
 #ifdef TCPPCAP
 	struct mbufq t_inpkts;		/* List of saved input packets. */
 	struct mbufq t_outpkts;		/* List of saved output packets. */