Index: tcp_usrreq.c
===================================================================
--- tcp_usrreq.c
+++ tcp_usrreq.c
@@ -133,6 +133,8 @@
 static void	tcp_usrclosed(struct tcpcb *);
 static void	tcp_fill_info(struct tcpcb *, struct tcp_info *);
 
+static int	tcp_options_support(struct tcpcb *tp, int flags);
+
 #ifdef TCPDEBUG
 #define	TCPDEBUG0	int ostate = 0
 #define	TCPDEBUG1()	ostate = tp ? tp->t_state : 0
@@ -979,6 +981,16 @@
 		goto out;
 	}
 	tp = intotcpcb(inp);
+	if ((flags & MSG_OOB) || (flags & PRUS_OOB)) {
+		if ((error = tcp_options_support(tp, PRUS_OOB)) != 0) {
+			if (control)
+				m_freem(control);
+			if (m && (flags & PRUS_NOTREADY) == 0)
+				m_freem(m);
+			error = ECONNRESET;
+			goto out;
+		}
+	}
 	TCPDEBUG1();
 	if (nam != NULL && tp->t_state < TCPS_SYN_SENT) {
 		switch (nam->sa_family) {
@@ -1362,6 +1374,19 @@
 	NET_EPOCH_EXIT(et);
 }
 
+static int 
+tcp_options_support(struct tcpcb *tp, int flags)
+{
+	/*
+	 * For now we say we support anything, we
+	 * need to change this so that we ask the
+	 * specific stack and let it decide if
+	 * it supports PRUS_OOB or possibly other
+	 * flags in the future.
+	 */
+	return (0);
+}
+
 /*
  * Receive out-of-band data.
  */
@@ -1381,6 +1406,10 @@
 		goto out;
 	}
 	tp = intotcpcb(inp);
+	error = tcp_options_support(tp, PRUS_OOB);
+	if (error) {
+		goto out;
+	}
 	TCPDEBUG1();
 	if ((so->so_oobmark == 0 &&
 	     (so->so_rcv.sb_state & SBS_RCVATMARK) == 0) ||