コード例 #1
0
ファイル: trpt.c プロジェクト: SylvestreG/bitrig
void
dotrace(caddr_t tcpcb)
{
	struct tcp_debug *td;
	int prev_debx = tcp_debx;
	int i;

 again:
	if (--tcp_debx < 0)
		tcp_debx = TCP_NDEBUG - 1;
	for (i = prev_debx % TCP_NDEBUG; i < TCP_NDEBUG; i++) {
		td = &tcp_debug[i];
		if (tcpcb && td->td_tcb != tcpcb)
			continue;
		ntime = ntohl(td->td_time);
		tcp_trace(td->td_act, td->td_ostate,
		    &td->td_cb, &td->td_ti,
		    &td->td_ti6, td->td_req);
		if (i == tcp_debx)
			goto done;
	}
	for (i = 0; i <= tcp_debx % TCP_NDEBUG; i++) {
		td = &tcp_debug[i];
		if (tcpcb && td->td_tcb != tcpcb)
			continue;
		ntime = ntohl(td->td_time);
		tcp_trace(td->td_act, td->td_ostate,
		    &td->td_cb, &td->td_ti,
		    &td->td_ti6, td->td_req);
	}
 done:
	if (follow) {
		prev_debx = tcp_debx + 1;
		if (prev_debx >= TCP_NDEBUG)
			prev_debx = 0;
		do {
			sleep(1);
			if (kvm_read(kd, nl[N_TCP_DEBX].n_value,
			    (char *)&tcp_debx, sizeof(tcp_debx)) !=
			    sizeof(tcp_debx))
				errx(3, "tcp_debx: %s", kvm_geterr(kd));
		} while (tcp_debx == prev_debx);

		if (kvm_read(kd, nl[N_TCP_DEBUG].n_value, (char *)tcp_debug,
		    sizeof(tcp_debug)) != sizeof(tcp_debug))
			errx(3, "tcp_debug: %s", kvm_geterr(kd));

		goto again;
	}
}
コード例 #2
0
ファイル: tcp_timer.c プロジェクト: dzavalishin/oskit
/*
 * Tcp protocol timeout routine called every 500 ms.
 * Updates the timers in all active tcb's and
 * causes finite state machine actions if timers expire.
 */
void
tcp_slowtimo()
{
	register struct inpcb *ip, *ipnxt;
	register struct tcpcb *tp;
	register int i;
	int s;
#ifdef TCPDEBUG
	int ostate;
#endif

	s = splnet();

	tcp_maxidle = tcp_keepcnt * tcp_keepintvl;

	ip = tcb.lh_first;
	if (ip == NULL) {
		splx(s);
		return;
	}
	/*
	 * Search through tcb's and update active timers.
	 */
	for (; ip != NULL; ip = ipnxt) {
		ipnxt = ip->inp_list.le_next;
		tp = intotcpcb(ip);
		if (tp == 0 || tp->t_state == TCPS_LISTEN)
			continue;
		for (i = 0; i < TCPT_NTIMERS; i++) {
			if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
#ifdef TCPDEBUG
				ostate = tp->t_state;
#endif
				tp = tcp_timers(tp, i);
				if (tp == NULL)
					goto tpgone;
#ifdef TCPDEBUG
				if (tp->t_inpcb->inp_socket->so_options
				    & SO_DEBUG)
					tcp_trace(TA_USER, ostate, tp,
						  (struct tcpiphdr *)0,
						  PRU_SLOWTIMO);
#endif
			}
		}
		tp->t_idle++;
		tp->t_duration++;
		if (tp->t_rtt)
			tp->t_rtt++;
tpgone:
		;
	}
	tcp_iss += TCP_ISSINCR/PR_SLOWHZ;		/* increment iss */
#ifdef TCP_COMPAT_42
	if ((int)tcp_iss < 0)
		tcp_iss = TCP_ISSINCR;			/* XXX */
#endif
	tcp_now++;					/* for timestamps */
	splx(s);
}
コード例 #3
0
ファイル: tcp_timer.c プロジェクト: Gwenio/DragonFlyBSD
/* Caller should be in critical section */
static struct tcpcb *
tcp_timer_2msl_handler(struct tcpcb *tp)
{
#ifdef TCPDEBUG
	int ostate;
#endif

#ifdef TCPDEBUG
	ostate = tp->t_state;
#endif
	/*
	 * 2 MSL timeout in shutdown went off.  If we're closed but
	 * still waiting for peer to close and connection has been idle
	 * too long, or if 2MSL time is up from TIME_WAIT, delete connection
	 * control block.  Otherwise, check again in a bit.
	 */
	if (tp->t_state != TCPS_TIME_WAIT &&
	    (ticks - tp->t_rcvtime) <= tp->t_maxidle) {
		tcp_callout_reset(tp, tp->tt_2msl, tp->t_keepintvl,
				  tcp_timer_2msl);
	} else {
		tp = tcp_close(tp);
	}

#ifdef TCPDEBUG
	if (tp && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
		tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO);
#endif
	return tp;
}
コード例 #4
0
ファイル: tcp_timer.c プロジェクト: Gwenio/DragonFlyBSD
/* Caller should be in critical section */
static struct tcpcb *
tcp_timer_persist_handler(struct tcpcb *tp)
{
#ifdef TCPDEBUG
	int ostate;
#endif

#ifdef TCPDEBUG
	ostate = tp->t_state;
#endif
	/*
	 * Persistance timer into zero window.
	 * Force a byte to be output, if possible.
	 */
	tcpstat.tcps_persisttimeo++;
	/*
	 * Hack: if the peer is dead/unreachable, we do not
	 * time out if the window is closed.  After a full
	 * backoff, drop the connection if the idle time
	 * (no responses to probes) reaches the maximum
	 * backoff that we would use if retransmitting.
	 */
	if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
	    ((ticks - tp->t_rcvtime) >= tcp_maxpersistidle ||
	     (ticks - tp->t_rcvtime) >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
		tcpstat.tcps_persistdrop++;
		tp = tcp_drop(tp, ETIMEDOUT);
		goto out;
	}
	tcp_setpersist(tp);
	tp->t_flags |= TF_FORCE;
	tcp_output(tp);
	tp->t_flags &= ~TF_FORCE;

out:
#ifdef TCPDEBUG
	if (tp && tp->t_inpcb->inp_socket->so_options & SO_DEBUG)
		tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO);
#endif
	return tp;
}
コード例 #5
0
ファイル: tcp_timer.c プロジェクト: jaredmcneill/freebsd
void
tcp_timer_keep(void *xtp)
{
	struct tcpcb *tp = xtp;
	struct tcptemp *t_template;
	struct inpcb *inp;
	CURVNET_SET(tp->t_vnet);
#ifdef TCPDEBUG
	int ostate;

	ostate = tp->t_state;
#endif
	inp = tp->t_inpcb;
	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
	INP_WLOCK(inp);
	if (callout_pending(&tp->t_timers->tt_keep) ||
	    !callout_active(&tp->t_timers->tt_keep)) {
		INP_WUNLOCK(inp);
		CURVNET_RESTORE();
		return;
	}
	callout_deactivate(&tp->t_timers->tt_keep);
	if ((inp->inp_flags & INP_DROPPED) != 0) {
		INP_WUNLOCK(inp);
		CURVNET_RESTORE();
		return;
	}
	KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
		("%s: tp %p tcpcb can't be stopped here", __func__, tp));

	/*
	 * Because we don't regularly reset the keepalive callout in
	 * the ESTABLISHED state, it may be that we don't actually need
	 * to send a keepalive yet. If that occurs, schedule another
	 * call for the next time the keepalive timer might expire.
	 */
	if (TCPS_HAVEESTABLISHED(tp->t_state)) {
		u_int idletime;

		idletime = ticks - tp->t_rcvtime;
		if (idletime < TP_KEEPIDLE(tp)) {
			callout_reset(&tp->t_timers->tt_keep,
			    TP_KEEPIDLE(tp) - idletime, tcp_timer_keep, tp);
			INP_WUNLOCK(inp);
			CURVNET_RESTORE();
			return;
		}
	}

	/*
	 * Keep-alive timer went off; send something
	 * or drop connection if idle for too long.
	 */
	TCPSTAT_INC(tcps_keeptimeo);
	if (tp->t_state < TCPS_ESTABLISHED)
		goto dropit;
	if ((always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
	    tp->t_state <= TCPS_CLOSING) {
		if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp))
			goto dropit;
		/*
		 * Send a packet designed to force a response
		 * if the peer is up and reachable:
		 * either an ACK if the connection is still alive,
		 * or an RST if the peer has closed the connection
		 * due to timeout or reboot.
		 * Using sequence number tp->snd_una-1
		 * causes the transmitted zero-length segment
		 * to lie outside the receive window;
		 * by the protocol spec, this requires the
		 * correspondent TCP to respond.
		 */
		TCPSTAT_INC(tcps_keepprobe);
		t_template = tcpip_maketemplate(inp);
		if (t_template) {
			tcp_respond(tp, t_template->tt_ipgen,
				    &t_template->tt_t, (struct mbuf *)NULL,
				    tp->rcv_nxt, tp->snd_una - 1, 0);
			free(t_template, M_TEMP);
		}
		callout_reset(&tp->t_timers->tt_keep, TP_KEEPINTVL(tp),
			      tcp_timer_keep, tp);
	} else
		callout_reset(&tp->t_timers->tt_keep, TP_KEEPIDLE(tp),
			      tcp_timer_keep, tp);

#ifdef TCPDEBUG
	if (inp->inp_socket->so_options & SO_DEBUG)
		tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
			  PRU_SLOWTIMO);
#endif
	TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
	INP_WUNLOCK(inp);
	CURVNET_RESTORE();
	return;

dropit:
	TCPSTAT_INC(tcps_keepdrops);

	if (tcp_inpinfo_lock_add(inp)) {
		tcp_inpinfo_lock_del(inp, tp);
		goto out;
	}
	tp = tcp_drop(tp, ETIMEDOUT);

#ifdef TCPDEBUG
	if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
		tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
			  PRU_SLOWTIMO);
#endif
	TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
	tcp_inpinfo_lock_del(inp, tp);
out:
	CURVNET_RESTORE();
}
コード例 #6
0
ファイル: tcp_timer.c プロジェクト: jaredmcneill/freebsd
void
tcp_timer_2msl(void *xtp)
{
	struct tcpcb *tp = xtp;
	struct inpcb *inp;
	CURVNET_SET(tp->t_vnet);
#ifdef TCPDEBUG
	int ostate;

	ostate = tp->t_state;
#endif
	inp = tp->t_inpcb;
	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
	INP_WLOCK(inp);
	tcp_free_sackholes(tp);
	if (callout_pending(&tp->t_timers->tt_2msl) ||
	    !callout_active(&tp->t_timers->tt_2msl)) {
		INP_WUNLOCK(tp->t_inpcb);
		CURVNET_RESTORE();
		return;
	}
	callout_deactivate(&tp->t_timers->tt_2msl);
	if ((inp->inp_flags & INP_DROPPED) != 0) {
		INP_WUNLOCK(inp);
		CURVNET_RESTORE();
		return;
	}
	KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
		("%s: tp %p tcpcb can't be stopped here", __func__, tp));
	/*
	 * 2 MSL timeout in shutdown went off.  If we're closed but
	 * still waiting for peer to close and connection has been idle
	 * too long delete connection control block.  Otherwise, check
	 * again in a bit.
	 *
	 * If in TIME_WAIT state just ignore as this timeout is handled in
	 * tcp_tw_2msl_scan().
	 *
	 * If fastrecycle of FIN_WAIT_2, in FIN_WAIT_2 and receiver has closed, 
	 * there's no point in hanging onto FIN_WAIT_2 socket. Just close it. 
	 * Ignore fact that there were recent incoming segments.
	 */
	if ((inp->inp_flags & INP_TIMEWAIT) != 0) {
		INP_WUNLOCK(inp);
		CURVNET_RESTORE();
		return;
	}
	if (tcp_fast_finwait2_recycle && tp->t_state == TCPS_FIN_WAIT_2 &&
	    tp->t_inpcb && tp->t_inpcb->inp_socket && 
	    (tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE)) {
		TCPSTAT_INC(tcps_finwait2_drops);
		if (tcp_inpinfo_lock_add(inp)) {
			tcp_inpinfo_lock_del(inp, tp);
			goto out;
		}
		tp = tcp_close(tp);             
		tcp_inpinfo_lock_del(inp, tp);
		goto out;
	} else {
		if (ticks - tp->t_rcvtime <= TP_MAXIDLE(tp)) {
			callout_reset(&tp->t_timers->tt_2msl,
				      TP_KEEPINTVL(tp), tcp_timer_2msl, tp);
		} else {
			if (tcp_inpinfo_lock_add(inp)) {
				tcp_inpinfo_lock_del(inp, tp);
				goto out;
			}
			tp = tcp_close(tp);
			tcp_inpinfo_lock_del(inp, tp);
			goto out;
		}
       }

#ifdef TCPDEBUG
	if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
		tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
			  PRU_SLOWTIMO);
#endif
	TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);

	if (tp != NULL)
		INP_WUNLOCK(inp);
out:
	CURVNET_RESTORE();
}
コード例 #7
0
ファイル: tcp_timer.c プロジェクト: yazshel/netbsd-kernel
void
tcp_timer_2msl(void *arg)
{
	struct tcpcb *tp = arg;
#ifdef TCP_DEBUG
	struct socket *so = NULL;
	short ostate;
#endif

	mutex_enter(softnet_lock);
	if ((tp->t_flags & TF_DEAD) != 0) {
		mutex_exit(softnet_lock);
		return;
	}
	if (!callout_expired(&tp->t_timer[TCPT_2MSL])) {
		mutex_exit(softnet_lock);
		return;
	}

	/*
	 * 2 MSL timeout went off, clear the SACK scoreboard, reset
	 * the FACK estimate.
	 */
	KERNEL_LOCK(1, NULL);
	tcp_free_sackholes(tp);
	tp->snd_fack = tp->snd_una;

#ifdef TCP_DEBUG
#ifdef INET
	if (tp->t_inpcb)
		so = tp->t_inpcb->inp_socket;
#endif
#ifdef INET6
	if (tp->t_in6pcb)
		so = tp->t_in6pcb->in6p_socket;
#endif

	ostate = tp->t_state;
#endif /* TCP_DEBUG */

	/*
	 * 2 MSL timeout in shutdown went off.  If we're closed but
	 * still waiting for peer to close and connection has been idle
	 * too long, or if 2MSL time is up from TIME_WAIT, delete connection
	 * control block.  Otherwise, check again in a bit.
	 */
	if (tp->t_state != TCPS_TIME_WAIT &&
	    ((tp->t_maxidle == 0) ||
	    ((tcp_now - tp->t_rcvtime) <= tp->t_maxidle)))
	    TCP_TIMER_ARM(tp, TCPT_2MSL, tp->t_keepintvl);
	else
		tp = tcp_close(tp);

#ifdef TCP_DEBUG
	if (tp && so->so_options & SO_DEBUG)
		tcp_trace(TA_USER, ostate, tp, NULL,
		    PRU_SLOWTIMO | (TCPT_2MSL << 8));
#endif
	mutex_exit(softnet_lock);
	KERNEL_UNLOCK_ONE(NULL);
}
コード例 #8
0
ファイル: tcp_timer.c プロジェクト: yazshel/netbsd-kernel
void
tcp_timer_keep(void *arg)
{
	struct tcpcb *tp = arg;
	struct socket *so = NULL;	/* Quell compiler warning */
#ifdef TCP_DEBUG
	short ostate;
#endif

	mutex_enter(softnet_lock);
	if ((tp->t_flags & TF_DEAD) != 0) {
		mutex_exit(softnet_lock);
		return;
	}
	if (!callout_expired(&tp->t_timer[TCPT_KEEP])) {
		mutex_exit(softnet_lock);
		return;
	}

	KERNEL_LOCK(1, NULL);

#ifdef TCP_DEBUG
	ostate = tp->t_state;
#endif /* TCP_DEBUG */

	/*
	 * Keep-alive timer went off; send something
	 * or drop connection if idle for too long.
	 */

	TCP_STATINC(TCP_STAT_KEEPTIMEO);
	if (TCPS_HAVEESTABLISHED(tp->t_state) == 0)
		goto dropit;
#ifdef INET
	if (tp->t_inpcb)
		so = tp->t_inpcb->inp_socket;
#endif
#ifdef INET6
	if (tp->t_in6pcb)
		so = tp->t_in6pcb->in6p_socket;
#endif
	KASSERT(so != NULL);
	if (so->so_options & SO_KEEPALIVE &&
	    tp->t_state <= TCPS_CLOSE_WAIT) {
	    	if ((tp->t_maxidle > 0) &&
		    ((tcp_now - tp->t_rcvtime) >=
		     tp->t_keepidle + tp->t_maxidle))
			goto dropit;
		/*
		 * Send a packet designed to force a response
		 * if the peer is up and reachable:
		 * either an ACK if the connection is still alive,
		 * or an RST if the peer has closed the connection
		 * due to timeout or reboot.
		 * Using sequence number tp->snd_una-1
		 * causes the transmitted zero-length segment
		 * to lie outside the receive window;
		 * by the protocol spec, this requires the
		 * correspondent TCP to respond.
		 */
		TCP_STATINC(TCP_STAT_KEEPPROBE);
		if (tcp_compat_42) {
			/*
			 * The keepalive packet must have nonzero
			 * length to get a 4.2 host to respond.
			 */
			(void)tcp_respond(tp, tp->t_template,
			    NULL, NULL, tp->rcv_nxt - 1,
			    tp->snd_una - 1, 0);
		} else {
			(void)tcp_respond(tp, tp->t_template,
			    NULL, NULL, tp->rcv_nxt,
			    tp->snd_una - 1, 0);
		}
		TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepintvl);
	} else
		TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle);

#ifdef TCP_DEBUG
	if (tp && so->so_options & SO_DEBUG)
		tcp_trace(TA_USER, ostate, tp, NULL,
		    PRU_SLOWTIMO | (TCPT_KEEP << 8));
#endif
	KERNEL_UNLOCK_ONE(NULL);
	mutex_exit(softnet_lock);
	return;

 dropit:
	TCP_STATINC(TCP_STAT_KEEPDROPS);
	(void) tcp_drop(tp, ETIMEDOUT);
	KERNEL_UNLOCK_ONE(NULL);
	mutex_exit(softnet_lock);
}
コード例 #9
0
ファイル: tcp_timer.c プロジェクト: yazshel/netbsd-kernel
void
tcp_timer_persist(void *arg)
{
	struct tcpcb *tp = arg;
	uint32_t rto;
#ifdef TCP_DEBUG
	struct socket *so = NULL;
	short ostate;
#endif

	mutex_enter(softnet_lock);
	if ((tp->t_flags & TF_DEAD) != 0) {
		mutex_exit(softnet_lock);
		return;
	}
	if (!callout_expired(&tp->t_timer[TCPT_PERSIST])) {
		mutex_exit(softnet_lock);
		return;
	}

	KERNEL_LOCK(1, NULL);
#ifdef TCP_DEBUG
#ifdef INET
	if (tp->t_inpcb)
		so = tp->t_inpcb->inp_socket;
#endif
#ifdef INET6
	if (tp->t_in6pcb)
		so = tp->t_in6pcb->in6p_socket;
#endif

	ostate = tp->t_state;
#endif /* TCP_DEBUG */

	/*
	 * Persistance timer into zero window.
	 * Force a byte to be output, if possible.
	 */

	/*
	 * Hack: if the peer is dead/unreachable, we do not
	 * time out if the window is closed.  After a full
	 * backoff, drop the connection if the idle time
	 * (no responses to probes) reaches the maximum
	 * backoff that we would use if retransmitting.
	 */
	rto = TCP_REXMTVAL(tp);
	if (rto < tp->t_rttmin)
		rto = tp->t_rttmin;
	if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
	    ((tcp_now - tp->t_rcvtime) >= tcp_maxpersistidle ||
	    (tcp_now - tp->t_rcvtime) >= rto * tcp_totbackoff)) {
		TCP_STATINC(TCP_STAT_PERSISTDROPS);
		tp = tcp_drop(tp, ETIMEDOUT);
		goto out;
	}
	TCP_STATINC(TCP_STAT_PERSISTTIMEO);
	tcp_setpersist(tp);
	tp->t_force = 1;
	(void) tcp_output(tp);
	tp->t_force = 0;

 out:
#ifdef TCP_DEBUG
	if (tp && so->so_options & SO_DEBUG)
		tcp_trace(TA_USER, ostate, tp, NULL,
		    PRU_SLOWTIMO | (TCPT_PERSIST << 8));
#endif
	KERNEL_UNLOCK_ONE(NULL);
	mutex_exit(softnet_lock);
}
コード例 #10
0
ファイル: tcp_timer.c プロジェクト: yazshel/netbsd-kernel
void
tcp_timer_rexmt(void *arg)
{
	struct tcpcb *tp = arg;
	uint32_t rto;
#ifdef TCP_DEBUG
	struct socket *so = NULL;
	short ostate;
#endif

	mutex_enter(softnet_lock);
	if ((tp->t_flags & TF_DEAD) != 0) {
		mutex_exit(softnet_lock);
		return;
	}
	if (!callout_expired(&tp->t_timer[TCPT_REXMT])) {
		mutex_exit(softnet_lock);
		return;
	}

	KERNEL_LOCK(1, NULL);
	if ((tp->t_flags & TF_PMTUD_PEND) && tp->t_inpcb &&
	    SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una) &&
	    SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_ourmss))) {
		extern struct sockaddr_in icmpsrc;
		struct icmp icmp;

		tp->t_flags &= ~TF_PMTUD_PEND;

		/* XXX create fake icmp message with relevant entries */
		icmp.icmp_nextmtu = tp->t_pmtud_nextmtu;
		icmp.icmp_ip.ip_len = tp->t_pmtud_ip_len;
		icmp.icmp_ip.ip_hl = tp->t_pmtud_ip_hl;
		icmpsrc.sin_addr = tp->t_inpcb->inp_faddr;
		icmp_mtudisc(&icmp, icmpsrc.sin_addr);

		/*
		 * Notify all connections to the same peer about
		 * new mss and trigger retransmit.
		 */
		in_pcbnotifyall(&tcbtable, icmpsrc.sin_addr, EMSGSIZE,
		    tcp_mtudisc);
		KERNEL_UNLOCK_ONE(NULL);
		mutex_exit(softnet_lock);
 		return;
 	}
#ifdef TCP_DEBUG
#ifdef INET
	if (tp->t_inpcb)
		so = tp->t_inpcb->inp_socket;
#endif
#ifdef INET6
	if (tp->t_in6pcb)
		so = tp->t_in6pcb->in6p_socket;
#endif
	ostate = tp->t_state;
#endif /* TCP_DEBUG */

	/*
	 * Clear the SACK scoreboard, reset FACK estimate.
	 */
	tcp_free_sackholes(tp);
	tp->snd_fack = tp->snd_una;

	/*
	 * Retransmission timer went off.  Message has not
	 * been acked within retransmit interval.  Back off
	 * to a longer retransmit interval and retransmit one segment.
	 */

	if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
		tp->t_rxtshift = TCP_MAXRXTSHIFT;
		TCP_STATINC(TCP_STAT_TIMEOUTDROP);
		tp = tcp_drop(tp, tp->t_softerror ?
		    tp->t_softerror : ETIMEDOUT);
		goto out;
	}
	TCP_STATINC(TCP_STAT_REXMTTIMEO);
	rto = TCP_REXMTVAL(tp);
	if (rto < tp->t_rttmin)
		rto = tp->t_rttmin;
	TCPT_RANGESET(tp->t_rxtcur, rto * tcp_backoff[tp->t_rxtshift],
	    tp->t_rttmin, TCPTV_REXMTMAX);
	TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur);

	/*
	 * If we are losing and we are trying path MTU discovery,
	 * try turning it off.  This will avoid black holes in
	 * the network which suppress or fail to send "packet
	 * too big" ICMP messages.  We should ideally do
	 * lots more sophisticated searching to find the right
	 * value here...
	 */
	if (tp->t_mtudisc && tp->t_rxtshift > TCP_MAXRXTSHIFT / 6) {
		TCP_STATINC(TCP_STAT_PMTUBLACKHOLE);

#ifdef INET
		/* try turning PMTUD off */
		if (tp->t_inpcb)
			tp->t_mtudisc = 0;
#endif
#ifdef INET6
		/* try using IPv6 minimum MTU */
		if (tp->t_in6pcb)
			tp->t_mtudisc = 0;
#endif

		/* XXX: more sophisticated Black hole recovery code? */
	}

	/*
	 * If losing, let the lower level know and try for
	 * a better route.  Also, if we backed off this far,
	 * our srtt estimate is probably bogus.  Clobber it
	 * so we'll take the next rtt measurement as our srtt;
	 * move the current srtt into rttvar to keep the current
	 * retransmit times until then.
	 */
	if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
#ifdef INET
		if (tp->t_inpcb)
			in_losing(tp->t_inpcb);
#endif
#ifdef INET6
		if (tp->t_in6pcb)
			in6_losing(tp->t_in6pcb);
#endif
		/*
		 * This operation is not described in RFC2988.  The
		 * point is to keep srtt+4*rttvar constant, so we
		 * should shift right 2 bits to divide by 4, and then
		 * shift right one bit because the storage
		 * representation of rttvar is 1/16s vs 1/32s for
		 * srtt.
		 */
		tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
		tp->t_srtt = 0;
	}
	tp->snd_nxt = tp->snd_una;
	tp->snd_high = tp->snd_max;
	/*
	 * If timing a segment in this window, stop the timer.
	 */
	tp->t_rtttime = 0;
	/*
	 * Remember if we are retransmitting a SYN, because if
	 * we do, set the initial congestion window must be set
	 * to 1 segment.
	 */
	if (tp->t_state == TCPS_SYN_SENT)
		tp->t_flags |= TF_SYN_REXMT;

	/*
	 * Adjust congestion control parameters.
	 */
	tp->t_congctl->slow_retransmit(tp);

	(void) tcp_output(tp);

 out:
#ifdef TCP_DEBUG
	if (tp && so->so_options & SO_DEBUG)
		tcp_trace(TA_USER, ostate, tp, NULL,
		    PRU_SLOWTIMO | (TCPT_REXMT << 8));
#endif
	KERNEL_UNLOCK_ONE(NULL);
	mutex_exit(softnet_lock);
}
コード例 #11
0
ファイル: trpt.c プロジェクト: kusumi/DragonFlyBSD
void
dotrace(caddr_t tcpcb)
{
	struct tcp_debug *td;
	int i;
	int prev_debx, family;

	prev_debx = tcp_debx;
again:	if (--tcp_debx < 0)
		tcp_debx = TCP_NDEBUG - 1;
	for (i = prev_debx % TCP_NDEBUG; i < TCP_NDEBUG; i++) {
		td = &tcp_debug[i];
		if (tcpcb && td->td_tcb != tcpcb)
			continue;
		ntime = ntohl(td->td_time);
#ifdef INET6
		family = td->td_family;
#else
		family = AF_INET;
#endif
		switch(family) {
		case AF_INET:
			tcp_trace(td->td_act, td->td_ostate,
				  (struct tcpcb *)td->td_tcb,
				  &td->td_cb, td->td_family, &td->td_ti.ti_i,
				  &td->td_ti.ti_t, td->td_req);
			break;
#ifdef INET6
		case AF_INET6:
			tcp_trace(td->td_act, td->td_ostate,
				  (struct tcpcb *)td->td_tcb,
				  &td->td_cb, td->td_family, &td->td_ti6.ip6,
				  &td->td_ti6.th, td->td_req);
			break;
#endif
		}
		if (i == tcp_debx)
			goto done;
	}
	for (i = 0; i <= tcp_debx % TCP_NDEBUG; i++) {
		td = &tcp_debug[i];
		if (tcpcb && td->td_tcb != tcpcb)
			continue;
		ntime = ntohl(td->td_time);
#ifdef INET6
		family = td->td_family;
#else
		family = AF_INET;
#endif
		switch(family) {
		case AF_INET:
			tcp_trace(td->td_act, td->td_ostate,
				  (struct tcpcb *)td->td_tcb,
				  &td->td_cb, td->td_family, &td->td_ti.ti_i,
				  &td->td_ti.ti_t, td->td_req);
			break;
#ifdef INET6
		case AF_INET6:
			tcp_trace(td->td_act, td->td_ostate,
				  (struct tcpcb *)td->td_tcb,
				  &td->td_cb, td->td_family, &td->td_ti6.ip6,
				  &td->td_ti6.th, td->td_req);
			break;
#endif
		}
	}
done:	if (follow) {
		prev_debx = tcp_debx + 1;
		if (prev_debx >= TCP_NDEBUG)
			prev_debx = 0;
		do {
			sleep(1);
			klseek(memf, (off_t)nl[N_TCP_DEBX].n_value, L_SET);
			if (read(memf, (char *)&tcp_debx, sizeof(tcp_debx)) !=
			    sizeof(tcp_debx))
				err(3, "tcp_debx");
		} while (tcp_debx == prev_debx);
		klseek(memf, (off_t)nl[N_TCP_DEBUG].n_value, L_SET);
		if (read(memf, (char *)tcp_debug, sizeof(tcp_debug)) !=
		    sizeof(tcp_debug))
			err(3, "tcp_debug");
		goto again;
	}
}
コード例 #12
0
ファイル: tcp_timer.c プロジェクト: carriercomm/libuinet
void
tcp_timer_2msl(void *xtp)
{
	struct tcpcb *tp = xtp;
	struct inpcb *inp;
	CURVNET_SET(tp->t_vnet);
#ifdef TCPDEBUG
	int ostate;

	ostate = tp->t_state;
#endif
	/*
	 * XXXRW: Does this actually happen?
	 */
	INP_INFO_WLOCK(&V_tcbinfo);
	inp = tp->t_inpcb;
	/*
	 * XXXRW: While this assert is in fact correct, bugs in the tcpcb
	 * tear-down mean we need it as a work-around for races between
	 * timers and tcp_discardcb().
	 *
	 * KASSERT(inp != NULL, ("tcp_timer_2msl: inp == NULL"));
	 */
	if (inp == NULL) {
		tcp_timer_race++;
		INP_INFO_WUNLOCK(&V_tcbinfo);
		CURVNET_RESTORE();
		return;
	}
	INP_WLOCK(inp);
	tcp_free_sackholes(tp);
	if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_2msl) ||
	    !callout_active(&tp->t_timers->tt_2msl)) {
		INP_WUNLOCK(tp->t_inpcb);
		INP_INFO_WUNLOCK(&V_tcbinfo);
		CURVNET_RESTORE();
		return;
	}
	callout_deactivate(&tp->t_timers->tt_2msl);
	/*
	 * 2 MSL timeout in shutdown went off.  If we're closed but
	 * still waiting for peer to close and connection has been idle
	 * too long, or if 2MSL time is up from TIME_WAIT, delete connection
	 * control block.  Otherwise, check again in a bit.
	 *
	 * If fastrecycle of FIN_WAIT_2, in FIN_WAIT_2 and receiver has closed, 
	 * there's no point in hanging onto FIN_WAIT_2 socket. Just close it. 
	 * Ignore fact that there were recent incoming segments.
	 */
	if (tcp_fast_finwait2_recycle && tp->t_state == TCPS_FIN_WAIT_2 &&
	    tp->t_inpcb && tp->t_inpcb->inp_socket && 
	    (tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE)) {
		TCPSTAT_INC(tcps_finwait2_drops);
		tp = tcp_close(tp);             
	} else {
		if (tp->t_state != TCPS_TIME_WAIT &&
		   ticks - tp->t_rcvtime <= TP_MAXIDLE(tp))
		       callout_reset_on(&tp->t_timers->tt_2msl,
			   TP_KEEPINTVL(tp), tcp_timer_2msl, tp, INP_CPU(inp));
	       else
		       tp = tcp_close(tp);
       }

#ifdef TCPDEBUG
	if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
		tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
			  PRU_SLOWTIMO);
#endif
	if (tp != NULL)
		INP_WUNLOCK(inp);
	INP_INFO_WUNLOCK(&V_tcbinfo);
	CURVNET_RESTORE();
}
コード例 #13
0
void
tcp_timer_keep(void *xtp)
{
	struct tcpcb *tp = xtp;
	struct tcptemp *t_template;
	struct inpcb *inp;
	CURVNET_SET(tp->t_vnet);
#ifdef TCPDEBUG
	int ostate;

	ostate = tp->t_state;
#endif
	INP_INFO_RLOCK(&V_tcbinfo);
	inp = tp->t_inpcb;
	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
	INP_WLOCK(inp);
	if (callout_pending(&tp->t_timers->tt_keep) ||
	    !callout_active(&tp->t_timers->tt_keep)) {
		INP_WUNLOCK(inp);
		INP_INFO_RUNLOCK(&V_tcbinfo);
		CURVNET_RESTORE();
		return;
	}
	callout_deactivate(&tp->t_timers->tt_keep);
	if ((inp->inp_flags & INP_DROPPED) != 0) {
		INP_WUNLOCK(inp);
		INP_INFO_RUNLOCK(&V_tcbinfo);
		CURVNET_RESTORE();
		return;
	}
	KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
		("%s: tp %p tcpcb can't be stopped here", __func__, tp));
	KASSERT((tp->t_timers->tt_flags & TT_KEEP) != 0,
		("%s: tp %p keep callout should be running", __func__, tp));
	/*
	 * Keep-alive timer went off; send something
	 * or drop connection if idle for too long.
	 */
	TCPSTAT_INC(tcps_keeptimeo);
	if (tp->t_state < TCPS_ESTABLISHED)
		goto dropit;
	if ((always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
	    tp->t_state <= TCPS_CLOSING) {
		if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp))
			goto dropit;
		/*
		 * Send a packet designed to force a response
		 * if the peer is up and reachable:
		 * either an ACK if the connection is still alive,
		 * or an RST if the peer has closed the connection
		 * due to timeout or reboot.
		 * Using sequence number tp->snd_una-1
		 * causes the transmitted zero-length segment
		 * to lie outside the receive window;
		 * by the protocol spec, this requires the
		 * correspondent TCP to respond.
		 */
		TCPSTAT_INC(tcps_keepprobe);
		t_template = tcpip_maketemplate(inp);
		if (t_template) {
			tcp_respond(tp, t_template->tt_ipgen,
				    &t_template->tt_t, (struct mbuf *)NULL,
				    tp->rcv_nxt, tp->snd_una - 1, 0);
			free(t_template, M_TEMP);
		}
		if (!callout_reset(&tp->t_timers->tt_keep, TP_KEEPINTVL(tp),
		    tcp_timer_keep, tp)) {
			tp->t_timers->tt_flags &= ~TT_KEEP_RST;
		}
	} else if (!callout_reset(&tp->t_timers->tt_keep, TP_KEEPIDLE(tp),
		    tcp_timer_keep, tp)) {
			tp->t_timers->tt_flags &= ~TT_KEEP_RST;
		}

#ifdef TCPDEBUG
	if (inp->inp_socket->so_options & SO_DEBUG)
		tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
			  PRU_SLOWTIMO);
#endif
	TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
	INP_WUNLOCK(inp);
	INP_INFO_RUNLOCK(&V_tcbinfo);
	CURVNET_RESTORE();
	return;

dropit:
	TCPSTAT_INC(tcps_keepdrops);
	tp = tcp_drop(tp, ETIMEDOUT);

#ifdef TCPDEBUG
	if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
		tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
			  PRU_SLOWTIMO);
#endif
	TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
	if (tp != NULL)
		INP_WUNLOCK(tp->t_inpcb);
	INP_INFO_RUNLOCK(&V_tcbinfo);
	CURVNET_RESTORE();
}
コード例 #14
0
ファイル: usnet_tcp_input.c プロジェクト: venkynv/libusnet
/*
 * TCP input routine, follows pages 65-76 of the
 * protocol specification dated September, 1981 very closely.
 */
void
tcp_input(usn_mbuf_t *m, int iphlen)
{
	struct tcpiphdr *ti;
	struct inpcb *inp;
	u_char *optp = NULL;
	int optlen;
	int len, tlen, off;
	struct tcpcb *tp = 0;
	int tiflags;
	struct usn_socket *so = 0;
	int todrop, acked, ourfinisacked;
   int needoutput = 0;
	short ostate;
	struct usn_in_addr laddr;
	int dropsocket = 0;
	int iss = 0;
	u_long tiwin, ts_val, ts_ecr;
	int ts_present = 0;

   (void)needoutput;
	g_tcpstat.tcps_rcvtotal++;
 
	// Get IP and TCP header together in first mbuf.
	// Note: IP leaves IP header in first mbuf.
	ti = mtod(m, struct tcpiphdr *);
	if (iphlen > sizeof (usn_ip_t))
		ip_stripoptions(m, (usn_mbuf_t *)0);
	if (m->mlen < sizeof (struct tcpiphdr)) {
		if ((m = m_pullup(m, sizeof (struct tcpiphdr))) == 0) {
			g_tcpstat.tcps_rcvshort++;
			return;
		}
		ti = mtod(m, struct tcpiphdr *);
	}

#ifdef DUMP_PAYLOAD
   dump_chain(m,"tcp");
#endif

   /*
	 * Checksum extended TCP header and data.
    */
	tlen = ntohs(((usn_ip_t *)ti)->ip_len);
	len = sizeof (usn_ip_t) + tlen;
	ti->ti_next = ti->ti_prev = 0;
	ti->ti_x1 = 0;
	ti->ti_len = (u_short)tlen;
	HTONS(ti->ti_len);
   ti->ti_sum = in_cksum(m, len);
	if (ti->ti_sum) {
		g_tcpstat.tcps_rcvbadsum++;
		goto drop;
	}
   /*
	 * Check that TCP offset makes sense,
	 * pull out TCP options and adjust length. XXX
    */
	off = ti->ti_off << 2;
	if (off < sizeof (struct tcphdr) || off > tlen) {
		g_tcpstat.tcps_rcvbadoff++;
		goto drop;
	}
	tlen -= off;
	ti->ti_len = tlen;
	if (off > sizeof (struct tcphdr)) {
		if (m->mlen < sizeof(usn_ip_t) + off) {
			if ((m = m_pullup(m, sizeof (usn_ip_t) + off)) == 0) {
				g_tcpstat.tcps_rcvshort++;
				return;
			}
			ti = mtod(m, struct tcpiphdr *);
		}
		optlen = off - sizeof (struct tcphdr);
		optp = mtod(m, u_char *) + sizeof (struct tcpiphdr);

      //	Do quick retrieval of timestamp options ("options
      // prediction?"). If timestamp is the only option and it's
      // formatted as recommended in RFC 1323 appendix A, we
      // quickly get the values now and not bother calling
      // tcp_dooptions(), etc.
		if ((optlen == TCPOLEN_TSTAMP_APPA ||
		     (optlen > TCPOLEN_TSTAMP_APPA &&
			optp[TCPOLEN_TSTAMP_APPA] == TCPOPT_EOL)) &&
		     *(u_int *)optp == htonl(TCPOPT_TSTAMP_HDR) &&
		     (ti->ti_flags & TH_SYN) == 0) {
			ts_present = 1;
			ts_val = ntohl(*(u_long *)(optp + 4));
			ts_ecr = ntohl(*(u_long *)(optp + 8));
			optp = NULL;	// we've parsed the options
		}
	}
	tiflags = ti->ti_flags;

	// Convert TCP protocol specific fields to host format.
	NTOHL(ti->ti_seq);
	NTOHL(ti->ti_ack);
	NTOHS(ti->ti_win);
	NTOHS(ti->ti_urp);

	// Locate pcb for segment.
findpcb:
	inp = g_tcp_last_inpcb;
	if (inp->inp_lport != ti->ti_dport ||
	    inp->inp_fport != ti->ti_sport ||
	    inp->inp_faddr.s_addr != ti->ti_src.s_addr ||
	    inp->inp_laddr.s_addr != ti->ti_dst.s_addr) {
		inp = in_pcblookup(&g_tcb, ti->ti_src, ti->ti_sport,
		    ti->ti_dst, ti->ti_dport, INPLOOKUP_WILDCARD);
		if (inp)
			g_tcp_last_inpcb = inp;
		++g_tcpstat.tcps_pcbcachemiss;
	}

	// If the state is CLOSED (i.e., TCB does not exist) then
	// all data in the incoming segment is discarded.
	// If the TCB exists but is in CLOSED state, it is embryonic,
	// but should either do a listen or a connect soon.
	if (inp == 0)
		goto dropwithreset;

	tp = intotcpcb(inp);

   DEBUG("found inp cb, laddr=%x, lport=%d, faddr=%x,"
         " fport=%d, tp_state=%d, tp_flags=%d",
         inp->inp_laddr.s_addr,
         inp->inp_lport,
         inp->inp_faddr.s_addr,
         inp->inp_fport, tp->t_state, tp->t_flags);

	if (tp == 0)
		goto dropwithreset;
	if (tp->t_state == TCPS_CLOSED)
		goto drop;
	
	// Unscale the window into a 32-bit value. 
	if ((tiflags & TH_SYN) == 0)
		tiwin = ti->ti_win << tp->snd_scale;
	else
		tiwin = ti->ti_win;

	so = inp->inp_socket;
   DEBUG("socket info, options=%x", so->so_options);

	if (so->so_options & (SO_DEBUG|SO_ACCEPTCONN)) {
		if (so->so_options & SO_DEBUG) {
			ostate = tp->t_state;
			g_tcp_saveti = *ti;
		}
		if (so->so_options & SO_ACCEPTCONN) {
			if ((tiflags & (TH_RST|TH_ACK|TH_SYN)) != TH_SYN) {
				// Note: dropwithreset makes sure we don't
				// send a reset in response to a RST.
				if (tiflags & TH_ACK) {
					g_tcpstat.tcps_badsyn++;
					goto dropwithreset;
				}
            DEBUG("SYN is expected, tiflags=%d", tiflags);
				goto drop;
			}
			so = sonewconn(so, 0);
			if (so == 0) {
            DEBUG("failed to create new connection, tiflags=%d", tiflags);
				goto drop;
         }

			// Mark socket as temporary until we're
			// committed to keeping it.  The code at
			// ``drop'' and ``dropwithreset'' check the
			// flag dropsocket to see if the temporary
			// socket created here should be discarded.
			// We mark the socket as discardable until
			// we're committed to it below in TCPS_LISTEN.
			dropsocket++;
			inp = (struct inpcb *)so->so_pcb;
			inp->inp_laddr = ti->ti_dst;
			inp->inp_lport = ti->ti_dport;

         // BSD >= 4.3
			inp->inp_options = ip_srcroute();

			tp = intotcpcb(inp);
			tp->t_state = TCPS_LISTEN;

			// Compute proper scaling value from buffer space
			while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
			   TCP_MAXWIN << tp->request_r_scale < so->so_rcv->sb_hiwat)
				tp->request_r_scale++;
		}
	}

	// Segment received on connection.
	// Reset idle time and keep-alive timer.
	tp->t_idle = 0;
	tp->t_timer[TCPT_KEEP] = g_tcp_keepidle;

	// Process options if not in LISTEN state,
	// else do it below (after getting remote address).
	if (optp && tp->t_state != TCPS_LISTEN)
		tcp_dooptions(tp, optp, optlen, ti,
			&ts_present, &ts_val, &ts_ecr);

	// Header prediction: check for the two common cases
	// of a uni-directional data xfer.  If the packet has
	// no control flags, is in-sequence, the window didn't
	// change and we're not retransmitting, it's a
	// candidate.  If the length is zero and the ack moved
	// forward, we're the sender side of the xfer.  Just
	// free the data acked & wake any higher level process
	// that was blocked waiting for space.  If the length
	// is non-zero and the ack didn't move, we're the
	// receiver side.  If we're getting packets in-order
	// (the reassembly queue is empty), add the data to
	// the socket buffer and note that we need a delayed ack.
	if (tp->t_state == TCPS_ESTABLISHED &&
	    (tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK &&
	    (!ts_present || TSTMP_GEQ(ts_val, tp->ts_recent)) &&
	    ti->ti_seq == tp->rcv_nxt &&
	    tiwin && tiwin == tp->snd_wnd &&
	    tp->snd_nxt == tp->snd_max) {
		// If last ACK falls within this segment's sequence numbers,
		// record the timestamp.
      if ( ts_present && TSTMP_GEQ(ts_val, tp->ts_recent) &&
            SEQ_LEQ(ti->ti_seq, tp->last_ack_sent) ){
			tp->ts_recent_age = g_tcp_now;
			tp->ts_recent = ts_val;
		}

		if (ti->ti_len == 0) {
			if (SEQ_GT(ti->ti_ack, tp->snd_una) &&
			    SEQ_LEQ(ti->ti_ack, tp->snd_max) &&
			    tp->snd_cwnd >= tp->snd_wnd) {
				// this is a pure ack for outstanding data.
				++g_tcpstat.tcps_predack;
				if (ts_present)
					tcp_xmit_timer(tp, g_tcp_now-ts_ecr+1);
				else if (tp->t_rtt &&
					    SEQ_GT(ti->ti_ack, tp->t_rtseq))
					tcp_xmit_timer(tp, tp->t_rtt);

				acked = ti->ti_ack - tp->snd_una;
				g_tcpstat.tcps_rcvackpack++;
				g_tcpstat.tcps_rcvackbyte += acked;
            TRACE("drop so_snd buffer, drop_bytes=%d, len=%d", 
                  acked, so->so_snd.sb_cc);

				sbdrop(so->so_snd, acked);
				tp->snd_una = ti->ti_ack;
				usn_free_cmbuf(m);

				// If all outstanding data are acked, stop
				// retransmit timer, otherwise restart timer
				// using current (possibly backed-off) value.
				// If process is waiting for space,
				// wakeup/selwakeup/signal.  If data
				// are ready to send, let tcp_output
				// decide between more output or persist.
				if (tp->snd_una == tp->snd_max)
					tp->t_timer[TCPT_REXMT] = 0;
				else if (tp->t_timer[TCPT_PERSIST] == 0)
					tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;

	         if (so->so_options & SO_DEBUG)
             	tcp_trace(TA_INPUT, ostate, tp, &g_tcp_saveti, 0);

				//if (so->so_snd->sb_flags & SB_NOTIFY) {
            //   usnet_tcpin_wwakeup(so, USN_TCP_IN, usn_tcpev_sbnotify, 0);
				//	sowwakeup(so);
            //}

            // send buffer is available for app thread. 
            usnet_tcpin_wwakeup(so, USN_TCP_IN, USN_TCPEV_WRITE, 0);

				if (so->so_snd->sb_cc)
					tcp_output(tp);
				return;
			}
		} else if (ti->ti_ack == tp->snd_una &&
		    tp->seg_next == (struct tcpiphdr *)tp &&
		    ti->ti_len <= sbspace(so->so_rcv)) {

			// this is a pure, in-sequence data packet
			// with nothing on the reassembly queue and
			// we have enough buffer space to take it.
			++g_tcpstat.tcps_preddat;
			tp->rcv_nxt += ti->ti_len;
			g_tcpstat.tcps_rcvpack++;
			g_tcpstat.tcps_rcvbyte += ti->ti_len;

			// Drop TCP, IP headers and TCP options then add data
			// to socket buffer.
			m->head += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
			m->mlen -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);

         TRACE("add data to rcv buf");
			sbappend(so->so_rcv, m);
			sorwakeup(so);

         // new data is available for app threads.
         usnet_tcpin_rwakeup(so, USN_TCP_IN, USN_TCPEV_READ, m);

	      if (so->so_options & SO_DEBUG) {
            TRACE("tcp trace, so_options=%d", so->so_options);
          	tcp_trace(TA_INPUT, ostate, tp, &g_tcp_saveti, 0);
         }

			tp->t_flags |= TF_DELACK;
			return;
		}
	}

	// Drop TCP, IP headers and TCP options.
	m->head += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
	m->mlen -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);

	// Calculate amount of space in receive window,
	// and then do TCP input processing.
	// Receive window is amount of space in rcv queue,
	// but not less than advertised window.
   {
	   int win;
	   win = sbspace(so->so_rcv);
	   if (win < 0)
	      win = 0;
  	   tp->rcv_wnd = max(win, (int)(tp->rcv_adv - tp->rcv_nxt));
	}

	switch (tp->t_state) {
	// If the state is LISTEN then ignore segment if it contains an RST.
	// If the segment contains an ACK then it is bad and send a RST.
	// If it does not contain a SYN then it is not interesting; drop it.
	// Don't bother responding if the destination was a broadcast.
	// Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial
	// tp->iss, and send a segment:
	//     <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>
	// Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss.
	// Fill in remote peer address fields if not previously specified.
	// Enter SYN_RECEIVED state, and process any other fields of this
	// segment in this state.
	case TCPS_LISTEN: {
		usn_mbuf_t *am;
		struct usn_sockaddr_in *sin;

		if (tiflags & TH_RST)
			goto drop;
		if (tiflags & TH_ACK)
			goto dropwithreset;
		if ((tiflags & TH_SYN) == 0)
			goto drop;

		// RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN
		// in_broadcast() should never return true on a received
		// packet with M_BCAST not set.

		//if (m->m_flags & (M_BCAST|M_MCAST) ||
		//    IN_MULTICAST(ntohl(ti->ti_dst.s_addr)))
		//	goto drop;

		am = usn_get_mbuf(0, BUF_MSIZE, 0);	// XXX: the size!
		if (am == NULL)
			goto drop;
		am->mlen = sizeof (struct usn_sockaddr_in);
		sin = mtod(am, struct usn_sockaddr_in *);
		sin->sin_family = AF_INET;
		sin->sin_len = sizeof(*sin);
		sin->sin_addr = ti->ti_src;
		sin->sin_port = ti->ti_sport;
		bzero((caddr_t)sin->sin_zero, sizeof(sin->sin_zero));

		laddr = inp->inp_laddr;
		if (inp->inp_laddr.s_addr == USN_INADDR_ANY)
			inp->inp_laddr = ti->ti_dst;

		if (in_pcbconnect(inp, am)) {
			inp->inp_laddr = laddr;
			usn_free_mbuf(am);
			goto drop;
		}
		usn_free_mbuf(am);
		tp->t_template = tcp_template(tp);
		if (tp->t_template == 0) {
			tp = tcp_drop(tp, ENOBUFS);
			dropsocket = 0;		// socket is already gone
			goto drop;
		}
		if (optp)
			tcp_dooptions(tp, optp, optlen, ti,
				&ts_present, &ts_val, &ts_ecr);
		if (iss)
			tp->iss = iss;
		else
			tp->iss = g_tcp_iss;
		g_tcp_iss += TCP_ISSINCR/4;
		tp->irs = ti->ti_seq;
		tcp_sendseqinit(tp);
		tcp_rcvseqinit(tp);
		tp->t_flags |= TF_ACKNOW;
      TRACE("change tcp state to TCPS_SYN_RECEIVED, state=%d, tp_flags=%d",
            tp->t_state, tp->t_flags);
		tp->t_state = TCPS_SYN_RECEIVED;

      // tcp event
      usnet_tcpin_ewakeup(so, USN_TCP_IN, USN_TCPST_SYN_RECEIVED, 0);

		tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
		dropsocket = 0;		// committed to socket
		g_tcpstat.tcps_accepts++;
		goto trimthenstep6;
	}


	// If the state is SYN_SENT:
	//	if seg contains an ACK, but not for our SYN, drop the input.
	//	if seg contains a RST, then drop the connection.
	//	if seg does not contain SYN, then drop it.
	// Otherwise this is an acceptable SYN segment
	//	initialize tp->rcv_nxt and tp->irs
	//	if seg contains ack then advance tp->snd_una
	//	if SYN has been acked change to ESTABLISHED else SYN_RCVD state
	//	arrange for segment to be acked (eventually)
	//	continue processing rest of data/controls, beginning with URG
	case TCPS_SYN_SENT:
		if ((tiflags & TH_ACK) &&
		    (SEQ_LEQ(ti->ti_ack, tp->iss) ||
		     SEQ_GT(ti->ti_ack, tp->snd_max)))
			goto dropwithreset;
		if (tiflags & TH_RST) {
			if (tiflags & TH_ACK)
				tp = tcp_drop(tp, ECONNREFUSED);
			goto drop;
		}
		if ((tiflags & TH_SYN) == 0)
			goto drop;
		if (tiflags & TH_ACK) {
			tp->snd_una = ti->ti_ack;
			if (SEQ_LT(tp->snd_nxt, tp->snd_una))
				tp->snd_nxt = tp->snd_una;
		   tp->t_timer[TCPT_REXMT] = 0; 
		}
		
		tp->irs = ti->ti_seq;
		tcp_rcvseqinit(tp);
		tp->t_flags |= TF_ACKNOW;
      TRACE("ack now, tp flags=%d", tp->t_flags);

      // XXX: remove second test.
		if (tiflags & TH_ACK /*&& SEQ_GT(tp->snd_una, tp->iss)*/) {
			g_tcpstat.tcps_connects++;
			soisconnected(so);
         TRACE("change tcp state to TCPS_ESTABLISHED,"
               " state=%d, tp_flags=%d", tp->t_state, tp->t_flags);
			tp->t_state = TCPS_ESTABLISHED;

			// Do window scaling on this connection?
			if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
				(TF_RCVD_SCALE|TF_REQ_SCALE)) {
				tp->snd_scale = tp->requested_s_scale;
				tp->rcv_scale = tp->request_r_scale;
			}
			tcp_reass(tp, (struct tcpiphdr *)0, (usn_mbuf_t *)0);

			// if we didn't have to retransmit the SYN,
			// use its rtt as our initial srtt & rtt var.
			if (tp->t_rtt)
				tcp_xmit_timer(tp, tp->t_rtt);
		} else {
         TRACE("change tcp state to TCPS_SYN_RECEIVED, state=%d, tp_flags=%d", 
               tp->t_state, tp->t_flags);
			tp->t_state = TCPS_SYN_RECEIVED;
         // tcp event
         usnet_tcpin_ewakeup(so, USN_TCP_IN, USN_TCPST_SYN_RECEIVED, 0);
      }

trimthenstep6:

		// Advance ti->ti_seq to correspond to first data byte.
		// If data, trim to stay within window,
		// dropping FIN if necessary.
		ti->ti_seq++;
		if (ti->ti_len > tp->rcv_wnd) {
			todrop = ti->ti_len - tp->rcv_wnd;
			m_adj(m, -todrop);
			ti->ti_len = tp->rcv_wnd;
			tiflags &= ~TH_FIN;
			g_tcpstat.tcps_rcvpackafterwin++;
			g_tcpstat.tcps_rcvbyteafterwin += todrop;
		}
		tp->snd_wl1 = ti->ti_seq - 1;
		tp->rcv_up = ti->ti_seq;
		goto step6;
	}

	// States other than LISTEN or SYN_SENT.
	// First check timestamp, if present.
	// Then check that at least some bytes of segment are within 
	// receive window.  If segment begins before rcv_nxt,
	// drop leading data (and SYN); if nothing left, just ack.
	// 
	// RFC 1323 PAWS: If we have a timestamp reply on this segment
	// and it's less than ts_recent, drop it.
	if (ts_present && (tiflags & TH_RST) == 0 && tp->ts_recent &&
	    TSTMP_LT(ts_val, tp->ts_recent)) {
		// Check to see if ts_recent is over 24 days old.
		if ((int)(g_tcp_now - tp->ts_recent_age) > TCP_PAWS_IDLE) {
			// Invalidate ts_recent.  If this segment updates
			// ts_recent, the age will be reset later and ts_recent
			// will get a valid value.  If it does not, setting
			// ts_recent to zero will at least satisfy the
			// requirement that zero be placed in the timestamp
			// echo reply when ts_recent isn't valid.  The
			// age isn't reset until we get a valid ts_recent
			// because we don't want out-of-order segments to be
			// dropped when ts_recent is old.
			tp->ts_recent = 0;
		} else {
			g_tcpstat.tcps_rcvduppack++;
			g_tcpstat.tcps_rcvdupbyte += ti->ti_len;
			g_tcpstat.tcps_pawsdrop++;
			goto dropafterack;
		}
	}

	todrop = tp->rcv_nxt - ti->ti_seq;
	if (todrop > 0) {
		if (tiflags & TH_SYN) {
			tiflags &= ~TH_SYN;
			ti->ti_seq++;
			if (ti->ti_urp > 1) 
				ti->ti_urp--;
			else
				tiflags &= ~TH_URG;
			todrop--;
		}
      if ( todrop >= ti->ti_len || 
           ( todrop == ti->ti_len && (tiflags & TH_FIN ) == 0 ) ) {
         // Any valid FIN must be to the left of the window.
         // At this point the FIN must be a duplicate or
         // out of sequence; drop it.
         tiflags &= ~TH_FIN;
         // Send an ACK to resynchronize and drop any data
         // But keep on processing for RST or ACK.
         tp->t_flags |= TF_ACKNOW;
         TRACE("send ack now to resync, tp_flags=%d", tp->t_flags);
         todrop = ti->ti_len;
         g_tcpstat.tcps_rcvdupbyte += ti->ti_len;
         g_tcpstat.tcps_rcvduppack++;
      } else {
         g_tcpstat.tcps_rcvpartduppack++;
         g_tcpstat.tcps_rcvpartdupbyte += ti->ti_len;
      }

		m_adj(m, todrop);
		ti->ti_seq += todrop;
		ti->ti_len -= todrop;
		if (ti->ti_urp > todrop)
			ti->ti_urp -= todrop;
		else {
			tiflags &= ~TH_URG;
			ti->ti_urp = 0;
		}
	}

	// If new data are received on a connection after the
	// user processes are gone, then RST the other end.
	if ((so->so_state & USN_NOFDREF) && 
	    tp->t_state > TCPS_CLOSE_WAIT && ti->ti_len) {
		tp = tcp_close(tp);
		g_tcpstat.tcps_rcvafterclose++;
		goto dropwithreset;
	}


	// If segment ends after window, drop trailing data
	// (and PUSH and FIN); if nothing left, just ACK.
	todrop = (ti->ti_seq+ti->ti_len) - (tp->rcv_nxt+tp->rcv_wnd);
	if (todrop > 0) {
		g_tcpstat.tcps_rcvpackafterwin++;
		if (todrop >= ti->ti_len) {
			g_tcpstat.tcps_rcvbyteafterwin += ti->ti_len;

			// If a new connection request is received
			// while in TIME_WAIT, drop the old connection
			// and start over if the sequence numbers
			// are above the previous ones.
			if (tiflags & TH_SYN &&
			    tp->t_state == TCPS_TIME_WAIT &&
			    SEQ_GT(ti->ti_seq, tp->rcv_nxt)) {
				iss = tp->snd_nxt + TCP_ISSINCR;
				tp = tcp_close(tp);
				goto findpcb;
			}

			// If window is closed can only take segments at
			// window edge, and have to drop data and PUSH from
			// incoming segments.  Continue processing, but
			// remember to ack.  Otherwise, drop segment
			// and ack.
			if (tp->rcv_wnd == 0 && ti->ti_seq == tp->rcv_nxt) {
				tp->t_flags |= TF_ACKNOW;
				g_tcpstat.tcps_rcvwinprobe++;
			} else
				goto dropafterack;
		} else
			g_tcpstat.tcps_rcvbyteafterwin += todrop;
		m_adj(m, -todrop);
		ti->ti_len -= todrop;
		tiflags &= ~(TH_PUSH|TH_FIN);
	}

   // check valid timestamp. Replace code above.
   if (ts_present && TSTMP_GEQ(ts_val, tp->ts_recent) &&
         SEQ_LEQ(ti->ti_seq, tp->last_ack_sent) ) {
		tp->ts_recent_age = g_tcp_now;
		tp->ts_recent = ts_val;
   }

	// If the RST bit is set examine the state:
	//    SYN_RECEIVED STATE:
	//	If passive open, return to LISTEN state.
	//	If active open, inform user that connection was refused.
	//    ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES:
	//	Inform user that connection was reset, and close tcb.
	//    CLOSING, LAST_ACK, TIME_WAIT STATES
	//	Close the tcb.
	if (tiflags&TH_RST) switch (tp->t_state) {

	case TCPS_SYN_RECEIVED:
		so->so_error = ECONNREFUSED;
		goto close;

	case TCPS_ESTABLISHED:
	case TCPS_FIN_WAIT_1:
	case TCPS_FIN_WAIT_2:
	case TCPS_CLOSE_WAIT:
		so->so_error = ECONNRESET;
close:
      DEBUG("change tcp state to TCPS_CLOSED, state=%d", tp->t_state);
		tp->t_state = TCPS_CLOSED;
      // tcp event
      usnet_tcpin_ewakeup(so, USN_TCP_IN, USN_TCPST_CLOSED, 0);
		g_tcpstat.tcps_drops++;
		tp = tcp_close(tp);
		goto drop;

	case TCPS_CLOSING:
	case TCPS_LAST_ACK:
	case TCPS_TIME_WAIT:
		tp = tcp_close(tp);
		goto drop;
	}

	// If a SYN is in the window, then this is an
	// error and we send an RST and drop the connection.
	if (tiflags & TH_SYN) {
		tp = tcp_drop(tp, ECONNRESET);
		goto dropwithreset;
	}

	// If the ACK bit is off we drop the segment and return.
	if ((tiflags & TH_ACK) == 0)
		goto drop;

	// Ack processing.
	switch (tp->t_state) {

	// In SYN_RECEIVED state if the ack ACKs our SYN then enter
	// ESTABLISHED state and continue processing, otherwise
	// send an RST.
	case TCPS_SYN_RECEIVED:
		if (SEQ_GT(tp->snd_una, ti->ti_ack) ||
		    SEQ_GT(ti->ti_ack, tp->snd_max))
			goto dropwithreset;
		g_tcpstat.tcps_connects++;

      DEBUG("change tcp state to TCPS_ESTABLISHED, state=%d", tp->t_state);
		tp->t_state = TCPS_ESTABLISHED;
		soisconnected(so);

		// Do window scaling?
		if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
			(TF_RCVD_SCALE|TF_REQ_SCALE)) {
			tp->snd_scale = tp->requested_s_scale;
			tp->rcv_scale = tp->request_r_scale;
		}
		tcp_reass(tp, (struct tcpiphdr *)0, (usn_mbuf_t *)0);
		tp->snd_wl1 = ti->ti_seq - 1;
		// fall into ...

	// In ESTABLISHED state: drop duplicate ACKs; ACK out of range
	// ACKs.  If the ack is in the range
	//	tp->snd_una < ti->ti_ack <= tp->snd_max
	// then advance tp->snd_una to ti->ti_ack and drop
	// data from the retransmission queue.  If this ACK reflects
	// more up to date window information we update our window information.
	case TCPS_ESTABLISHED:
	case TCPS_FIN_WAIT_1:
	case TCPS_FIN_WAIT_2:
	case TCPS_CLOSE_WAIT:
	case TCPS_CLOSING:
	case TCPS_LAST_ACK:
	case TCPS_TIME_WAIT:

		if (SEQ_LEQ(ti->ti_ack, tp->snd_una)) {
			if (ti->ti_len == 0 && tiwin == tp->snd_wnd) {
				g_tcpstat.tcps_rcvdupack++;
				// If we have outstanding data (other than
				// a window probe), this is a completely
				// duplicate ack (ie, window info didn't
				// change), the ack is the biggest we've
				// seen and we've seen exactly our rexmt
				// threshhold of them, assume a packet
				// has been dropped and retransmit it.
				// Kludge snd_nxt & the congestion
				// window so we send only this one
				// packet.
				//
				// We know we're losing at the current
				// window size so do congestion avoidance
				// (set ssthresh to half the current window
				// and pull our congestion window back to
				// the new ssthresh).
				//
				// Dup acks mean that packets have left the
				// network (they're now cached at the receiver) 
				// so bump cwnd by the amount in the receiver
				// to keep a constant cwnd packets in the
				// network.
				if (tp->t_timer[TCPT_REXMT] == 0 ||
				    ti->ti_ack != tp->snd_una)
					tp->t_dupacks = 0;
				else if (++tp->t_dupacks == g_tcprexmtthresh) {
               // congestion avoidance
					tcp_seq onxt = tp->snd_nxt;
					u_int win =
					    min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg;

					if (win < 2)
						win = 2;
					tp->snd_ssthresh = win * tp->t_maxseg;
					tp->t_timer[TCPT_REXMT] = 0;
					tp->t_rtt = 0;
					tp->snd_nxt = ti->ti_ack;
					tp->snd_cwnd = tp->t_maxseg;
					tcp_output(tp);
					tp->snd_cwnd = tp->snd_ssthresh +
					       tp->t_maxseg * tp->t_dupacks;
					if (SEQ_GT(onxt, tp->snd_nxt))
						tp->snd_nxt = onxt;
					goto drop;
				} else if (tp->t_dupacks > g_tcprexmtthresh) {
					tp->snd_cwnd += tp->t_maxseg;
					tcp_output(tp);
					goto drop;
				}
			} else
				tp->t_dupacks = 0;
			break;
		}

		// If the congestion window was inflated to account
		// for the other side's cached packets, retract it.
		if (tp->t_dupacks > g_tcprexmtthresh &&
		    tp->snd_cwnd > tp->snd_ssthresh)
			tp->snd_cwnd = tp->snd_ssthresh;
		tp->t_dupacks = 0;
		if (SEQ_GT(ti->ti_ack, tp->snd_max)) {
			g_tcpstat.tcps_rcvacktoomuch++;
			goto dropafterack;
		}
		acked = ti->ti_ack - tp->snd_una;
		g_tcpstat.tcps_rcvackpack++;
		g_tcpstat.tcps_rcvackbyte += acked;

		// If we have a timestamp reply, update smoothed
		// round trip time.  If no timestamp is present but
		// transmit timer is running and timed sequence
		// number was acked, update smoothed round trip time.
		// Since we now have an rtt measurement, cancel the
		// timer backoff (cf., Phil Karn's retransmit alg.).
		// Recompute the initial retransmit timer.
		if (ts_present)
			tcp_xmit_timer(tp, g_tcp_now-ts_ecr+1);
		else if (tp->t_rtt && SEQ_GT(ti->ti_ack, tp->t_rtseq))
			tcp_xmit_timer(tp,tp->t_rtt);

		// If all outstanding data is acked, stop retransmit
		// timer and remember to restart (more output or persist).
		// If there is more data to be acked, restart retransmit
		// timer, using current (possibly backed-off) value.
		if (ti->ti_ack == tp->snd_max) {
			tp->t_timer[TCPT_REXMT] = 0;
         DEBUG("change needoutput to 1");
			needoutput = 1;
         tp->t_flags |= TF_NEEDOUTPUT;
		} else if (tp->t_timer[TCPT_PERSIST] == 0)
			tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;

		// When new data is acked, open the congestion window.
		// If the window gives us less than ssthresh packets
		// in flight, open exponentially (maxseg per packet).
		// Otherwise open linearly: maxseg per window
		// (maxseg * (maxseg / cwnd) per packet).
		{
		   u_int cw = tp->snd_cwnd;
	   	u_int incr = tp->t_maxseg;

	   	if (cw > tp->snd_ssthresh)
	   		incr = incr * incr / cw;
   		tp->snd_cwnd = min(cw + incr, TCP_MAXWIN<<tp->snd_scale);
		}

		if (acked > so->so_snd->sb_cc) {
			tp->snd_wnd -= so->so_snd->sb_cc;
         DEBUG("drop all so_snd buffer, drop_bytes=%d, acked=%d", 
               so->so_snd->sb_cc, acked);
			sbdrop(so->so_snd, (int)so->so_snd->sb_cc);
			ourfinisacked = 1;
		} else {
         DEBUG("drop so_snd buffer, drop_bytes=%d, len=%d", acked, so->so_snd->sb_cc);
			sbdrop(so->so_snd, acked);
			tp->snd_wnd -= acked;
			ourfinisacked = 0;
		}
		//if (so->so_snd->sb_flags & SB_NOTIFY) {
			sowwakeup(so);
         usnet_tcpin_wwakeup(so, USN_TCP_IN, USN_TCPEV_WRITE, 0);
      //}

		tp->snd_una = ti->ti_ack;
		if (SEQ_LT(tp->snd_nxt, tp->snd_una))
			tp->snd_nxt = tp->snd_una;

		switch (tp->t_state) {

		// In FIN_WAIT_1 STATE in addition to the processing
		// for the ESTABLISHED state if our FIN is now acknowledged
		// then enter FIN_WAIT_2.
		case TCPS_FIN_WAIT_1:
			if (ourfinisacked) {
				// If we can't receive any more
				// data, then closing user can proceed.
				// Starting the timer is contrary to the
				// specification, but if we don't get a FIN
				// we'll hang forever.
				if (so->so_state & USN_CANTRCVMORE) {
					soisdisconnected(so);
					tp->t_timer[TCPT_2MSL] = g_tcp_maxidle;
				}
            DEBUG("change tcp state to TCPS_FIN_WAIT_2, state=%d", tp->t_state);
				tp->t_state = TCPS_FIN_WAIT_2;
            usnet_tcpin_ewakeup(so, USN_TCP_IN, USN_TCPST_FIN_WAIT2, 0);
			}
			break;

		// In CLOSING STATE in addition to the processing for
		// the ESTABLISHED state if the ACK acknowledges our FIN
		// then enter the TIME-WAIT state, otherwise ignore
		// the segment.
		case TCPS_CLOSING:
			if (ourfinisacked) {
            DEBUG("change tcp state to TCPS_TIME_WAIT, state=%d", tp->t_state);
				tp->t_state = TCPS_TIME_WAIT;
            usnet_tcpin_ewakeup(so, USN_TCP_IN, USN_TCPST_TIME_WAIT, 0);
				tcp_canceltimers(tp);
				tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
				soisdisconnected(so);
			}
			break;
		
		// In LAST_ACK, we may still be waiting for data to drain
		// and/or to be acked, as well as for the ack of our FIN.
		// If our FIN is now acknowledged, delete the TCB,
		// enter the closed state and return.
		case TCPS_LAST_ACK:
			if (ourfinisacked) {
				tp = tcp_close(tp);
				goto drop;
			}
			break;


		// In TIME_WAIT state the only thing that should arrive
		// is a retransmission of the remote FIN.  Acknowledge
		// it and restart the finack timer.
		case TCPS_TIME_WAIT:
			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
			goto dropafterack;
		}
	}

step6:

	// Update window information.
	// Don't look at window if no ACK: TAC's send garbage on first SYN.
	if ((tiflags & TH_ACK) &&
	    (SEQ_LT(tp->snd_wl1, ti->ti_seq) || 
        (tp->snd_wl1 == ti->ti_seq && (SEQ_LT(tp->snd_wl2, ti->ti_ack) ||
	     (tp->snd_wl2 == ti->ti_ack && tiwin > tp->snd_wnd) ))  )) {
		// keep track of pure window updates
		if (ti->ti_len == 0 &&
		    tp->snd_wl2 == ti->ti_ack && tiwin > tp->snd_wnd)
			g_tcpstat.tcps_rcvwinupd++;
		tp->snd_wnd = tiwin;
		tp->snd_wl1 = ti->ti_seq;
		tp->snd_wl2 = ti->ti_ack;
		if (tp->snd_wnd > tp->max_sndwnd)
			tp->max_sndwnd = tp->snd_wnd;
      DEBUG("change needoutput to 1");
      tp->t_flags |= TF_NEEDOUTPUT;
		needoutput = 1;
	}

	
	// Process segments with URG.
	if ((tiflags & TH_URG) && ti->ti_urp &&
	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {

		// This is a kludge, but if we receive and accept
		// random urgent pointers, we'll crash in
		// soreceive.  It's hard to imagine someone
		// actually wanting to send this much urgent data.
		if (ti->ti_urp + so->so_rcv->sb_cc > g_sb_max) {
			ti->ti_urp = 0;			// XXX
			tiflags &= ~TH_URG;		// XXX
			goto dodata;			// XXX
		}

		// If this segment advances the known urgent pointer,
		// then mark the data stream.  This should not happen
		// in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since
		// a FIN has been received from the remote side. 
		// In these states we ignore the URG.
		//
		// According to RFC961 (Assigned Protocols),
		// the urgent pointer points to the last octet
		// of urgent data.  We continue, however,
		// to consider it to indicate the first octet
		// of data past the urgent section as the original 
		// spec states (in one of two places).
		if (SEQ_GT(ti->ti_seq+ti->ti_urp, tp->rcv_up)) {
			tp->rcv_up = ti->ti_seq + ti->ti_urp;
			so->so_oobmark = so->so_rcv->sb_cc +
			    (tp->rcv_up - tp->rcv_nxt) - 1;
			if (so->so_oobmark == 0)
				so->so_state |= USN_RCVATMARK;
			sohasoutofband(so);
         // send async event to app threads.
         usnet_tcpin_ewakeup(so, USN_TCP_IN, USN_TCPEV_OUTOFBOUND, 0);
			tp->t_oobflags &= ~(TCPOOB_HAVEDATA | TCPOOB_HADDATA);
		}

		// Remove out of band data so doesn't get presented to user.
		// This can happen independent of advancing the URG pointer,
		// but if two URG's are pending at once, some out-of-band
		// data may creep in... ick.
		if (ti->ti_urp <= ti->ti_len
#ifdef SO_OOBINLINE
		     && (so->so_options & SO_OOBINLINE) == 0
#endif
		     )
			tcp_pulloutofband(so, ti, m);
	} else
		// If no out of band data is expected,
		// pull receive urgent pointer along
		// with the receive window.
		if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))
			tp->rcv_up = tp->rcv_nxt;
dodata:							// XXX
#ifdef DUMP_PAYLOAD
   DEBUG("Handle data");
   dump_chain(m,"tcp");
#endif

	// Process the segment text, merging it into the TCP sequencing queue,
	// and arranging for acknowledgment of receipt if necessary.
	// This process logically involves adjusting tp->rcv_wnd as data
	// is presented to the user (this happens in tcp_usrreq.c,
	// case PRU_RCVD).  If a FIN has already been received on this
	// connection then we just ignore the text.
	if ((ti->ti_len || (tiflags&TH_FIN)) &&
	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
		TCP_REASS(tp, ti, m, so, tiflags);
		// Note the amount of data that peer has sent into
		// our window, in order to estimate the sender's
		// buffer size.
		len = so->so_rcv->sb_hiwat - (tp->rcv_adv - tp->rcv_nxt);
	} else {
		usn_free_cmbuf(m);
		tiflags &= ~TH_FIN;
	}

	// If FIN is received ACK the FIN and let the user know
	// that the connection is closing.
	if (tiflags & TH_FIN) {
		if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
			socantrcvmore(so);
			tp->t_flags |= TF_ACKNOW;
         TRACE("ack FIN now, tp flags=%d", tp->t_flags);
			tp->rcv_nxt++;
		}
		switch (tp->t_state) {

		// In SYN_RECEIVED and ESTABLISHED STATES
		// enter the CLOSE_WAIT state.
		case TCPS_SYN_RECEIVED:
		case TCPS_ESTABLISHED:
         TRACE("change tcp state to TCPS_CLOSE_WAIT, state=%d", tp->t_state);
			tp->t_state = TCPS_CLOSE_WAIT;
         soewakeup(so, 0);
         usnet_tcpin_ewakeup(so, USN_TCP_IN, USN_TCPST_CLOSE_WAIT, 0);
			break;

		// If still in FIN_WAIT_1 STATE FIN has not been acked so
		// enter the CLOSING state.
		case TCPS_FIN_WAIT_1:
         TRACE("change tcp state to TCPS_CLOSING, state=%d", tp->t_state);
			tp->t_state = TCPS_CLOSING;
         usnet_tcpin_ewakeup(so, USN_TCP_IN, USN_TCPST_CLOSING, 0);
			break;

		// In FIN_WAIT_2 state enter the TIME_WAIT state,
		// starting the time-wait timer, turning off the other 
		// standard timers.
		case TCPS_FIN_WAIT_2:
         TRACE("change tcp state to TCPS_TIME_WAIT, state=%d", tp->t_state);
			tp->t_state = TCPS_TIME_WAIT;
			tcp_canceltimers(tp);
			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
			soisdisconnected(so);
         usnet_tcpin_ewakeup(so, USN_TCP_IN, USN_TCPST_TIME_WAIT, 0);
			break;

		// In TIME_WAIT state restart the 2 MSL time_wait timer.
		case TCPS_TIME_WAIT:
			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
			break;
		}
	}
	if (so->so_options & SO_DEBUG) {
      TRACE("tcp trace, so_options=%d", so->so_options);
		tcp_trace(TA_INPUT, ostate, tp, &g_tcp_saveti, 0);
   }

	// Return any desired output.
	//if (needoutput || (tp->t_flags & TF_ACKNOW)){
	if (tp->t_flags & TF_NEEDOUTPUT || (tp->t_flags & TF_ACKNOW)){
      TRACE("ack now or need to ouput, tp->t_flags=%d", tp->t_flags);
		tcp_output(tp);
   }
	return;

dropafterack:
   TRACE("dropafterack");
	// Generate an ACK dropping incoming segment if it occupies
	// sequence space, where the ACK reflects our state.
	if (tiflags & TH_RST)
		goto drop;
	usn_free_cmbuf(m);
	tp->t_flags |= TF_ACKNOW;
   TRACE("ack now, tp flags=%d", tp->t_flags);
	tcp_output(tp);
	return;

dropwithreset:
   TRACE("dropwithreset");
	// Generate a RST, dropping incoming segment.
	// Make ACK acceptable to originator of segment.
	// Don't bother to respond if destination was broadcast/multicast.
#define USN_MULTICAST(i) (((u_int)(i) & 0xf0000000) == 0xe0000000)
	if ((tiflags & TH_RST) || m->flags & (BUF_BCAST|BUF_MCAST) ||
	    USN_MULTICAST(ntohl(ti->ti_dst.s_addr)))
		goto drop;
   
	if (tiflags & TH_ACK)
		tcp_respond(tp, ti, m, (tcp_seq)0, ti->ti_ack, TH_RST);
	else {
		if (tiflags & TH_SYN)
			ti->ti_len++;
		tcp_respond(tp, ti, m, ti->ti_seq+ti->ti_len, (tcp_seq)0,
		    TH_RST|TH_ACK);
	}
	// destroy temporarily created socket
	if (dropsocket)
		soabort(so);
	return;

drop:
   TRACE("drop");
	// Drop space held by incoming segment and return.
	if (tp && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) {
      TRACE("tcp trace: drop a socket");
		tcp_trace(TA_DROP, ostate, tp, &g_tcp_saveti, 0);
   }
	usn_free_cmbuf(m);
	// destroy temporarily created socket
	if (dropsocket)
		soabort(so);
	return;
}
コード例 #15
0
ファイル: tcp_timer.c プロジェクト: Gwenio/DragonFlyBSD
/* Caller should be in critical section */
static struct tcpcb *
tcp_timer_keep_handler(struct tcpcb *tp)
{
	struct tcptemp *t_template;
#ifdef TCPDEBUG
	int ostate = tp->t_state;
#endif

	/*
	 * Keep-alive timer went off; send something
	 * or drop connection if idle for too long.
	 */
	tcpstat.tcps_keeptimeo++;
	if (tp->t_state < TCPS_ESTABLISHED)
		goto dropit;
	if ((always_keepalive || (tp->t_flags & TF_KEEPALIVE) ||
	     (tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE)) &&
	    tp->t_state <= TCPS_CLOSING) {
		if ((ticks - tp->t_rcvtime) >= tp->t_keepidle + tp->t_maxidle)
			goto dropit;
		/*
		 * Send a packet designed to force a response
		 * if the peer is up and reachable:
		 * either an ACK if the connection is still alive,
		 * or an RST if the peer has closed the connection
		 * due to timeout or reboot.
		 * Using sequence number tp->snd_una-1
		 * causes the transmitted zero-length segment
		 * to lie outside the receive window;
		 * by the protocol spec, this requires the
		 * correspondent TCP to respond.
		 */
		tcpstat.tcps_keepprobe++;
		t_template = tcp_maketemplate(tp);
		if (t_template) {
			tcp_respond(tp, t_template->tt_ipgen,
				    &t_template->tt_t, NULL,
				    tp->rcv_nxt, tp->snd_una - 1, 0);
			tcp_freetemplate(t_template);
		}
		tcp_callout_reset(tp, tp->tt_keep, tp->t_keepintvl,
				  tcp_timer_keep);
	} else {
		tcp_callout_reset(tp, tp->tt_keep, tp->t_keepidle,
				  tcp_timer_keep);
	}

#ifdef TCPDEBUG
	if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)
		tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO);
#endif
	return tp;

dropit:
	tcpstat.tcps_keepdrops++;
	tp = tcp_drop(tp, ETIMEDOUT);

#ifdef TCPDEBUG
	if (tp && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
		tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO);
#endif
	return tp;
}
コード例 #16
0
ファイル: tcp_timer.c プロジェクト: jaredmcneill/freebsd
void
tcp_timer_persist(void *xtp)
{
	struct tcpcb *tp = xtp;
	struct inpcb *inp;
	CURVNET_SET(tp->t_vnet);
#ifdef TCPDEBUG
	int ostate;

	ostate = tp->t_state;
#endif
	inp = tp->t_inpcb;
	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
	INP_WLOCK(inp);
	if (callout_pending(&tp->t_timers->tt_persist) ||
	    !callout_active(&tp->t_timers->tt_persist)) {
		INP_WUNLOCK(inp);
		CURVNET_RESTORE();
		return;
	}
	callout_deactivate(&tp->t_timers->tt_persist);
	if ((inp->inp_flags & INP_DROPPED) != 0) {
		INP_WUNLOCK(inp);
		CURVNET_RESTORE();
		return;
	}
	KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
		("%s: tp %p tcpcb can't be stopped here", __func__, tp));
	/*
	 * Persistence timer into zero window.
	 * Force a byte to be output, if possible.
	 */
	TCPSTAT_INC(tcps_persisttimeo);
	/*
	 * Hack: if the peer is dead/unreachable, we do not
	 * time out if the window is closed.  After a full
	 * backoff, drop the connection if the idle time
	 * (no responses to probes) reaches the maximum
	 * backoff that we would use if retransmitting.
	 */
	if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
	    (ticks - tp->t_rcvtime >= tcp_maxpersistidle ||
	     ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
		TCPSTAT_INC(tcps_persistdrop);
		if (tcp_inpinfo_lock_add(inp)) {
			tcp_inpinfo_lock_del(inp, tp);
			goto out;
		}
		tp = tcp_drop(tp, ETIMEDOUT);
		tcp_inpinfo_lock_del(inp, tp);
		goto out;
	}
	/*
	 * If the user has closed the socket then drop a persisting
	 * connection after a much reduced timeout.
	 */
	if (tp->t_state > TCPS_CLOSE_WAIT &&
	    (ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) {
		TCPSTAT_INC(tcps_persistdrop);
		if (tcp_inpinfo_lock_add(inp)) {
			tcp_inpinfo_lock_del(inp, tp);
			goto out;
		}
		tp = tcp_drop(tp, ETIMEDOUT);
		tcp_inpinfo_lock_del(inp, tp);
		goto out;
	}
	tcp_setpersist(tp);
	tp->t_flags |= TF_FORCEDATA;
	(void) tp->t_fb->tfb_tcp_output(tp);
	tp->t_flags &= ~TF_FORCEDATA;

#ifdef TCPDEBUG
	if (tp != NULL && tp->t_inpcb->inp_socket->so_options & SO_DEBUG)
		tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO);
#endif
	TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
	INP_WUNLOCK(inp);
out:
	CURVNET_RESTORE();
}
コード例 #17
0
ファイル: tcp_timer.c プロジェクト: carriercomm/libuinet
void
tcp_timer_persist(void *xtp)
{
	struct tcpcb *tp = xtp;
	struct inpcb *inp;
	CURVNET_SET(tp->t_vnet);
#ifdef TCPDEBUG
	int ostate;

	ostate = tp->t_state;
#endif
	INP_INFO_WLOCK(&V_tcbinfo);
	inp = tp->t_inpcb;
	/*
	 * XXXRW: While this assert is in fact correct, bugs in the tcpcb
	 * tear-down mean we need it as a work-around for races between
	 * timers and tcp_discardcb().
	 *
	 * KASSERT(inp != NULL, ("tcp_timer_persist: inp == NULL"));
	 */
	if (inp == NULL) {
		tcp_timer_race++;
		INP_INFO_WUNLOCK(&V_tcbinfo);
		CURVNET_RESTORE();
		return;
	}
	INP_WLOCK(inp);
	if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_persist)
	    || !callout_active(&tp->t_timers->tt_persist)) {
		INP_WUNLOCK(inp);
		INP_INFO_WUNLOCK(&V_tcbinfo);
		CURVNET_RESTORE();
		return;
	}
	callout_deactivate(&tp->t_timers->tt_persist);
	/*
	 * Persistance timer into zero window.
	 * Force a byte to be output, if possible.
	 */
	TCPSTAT_INC(tcps_persisttimeo);
	/*
	 * Hack: if the peer is dead/unreachable, we do not
	 * time out if the window is closed.  After a full
	 * backoff, drop the connection if the idle time
	 * (no responses to probes) reaches the maximum
	 * backoff that we would use if retransmitting.
	 */
	if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
	    (ticks - tp->t_rcvtime >= tcp_maxpersistidle ||
	     ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
		TCPSTAT_INC(tcps_persistdrop);
		tp = tcp_drop(tp, ETIMEDOUT);
		goto out;
	}
	tcp_setpersist(tp);
	tp->t_flags |= TF_FORCEDATA;
	(void) tcp_output(tp);
	tp->t_flags &= ~TF_FORCEDATA;

out:
#ifdef TCPDEBUG
	if (tp != NULL && tp->t_inpcb->inp_socket->so_options & SO_DEBUG)
		tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO);
#endif
	if (tp != NULL)
		INP_WUNLOCK(inp);
	INP_INFO_WUNLOCK(&V_tcbinfo);
	CURVNET_RESTORE();
}
コード例 #18
0
ファイル: tcp_timer.c プロジェクト: carriercomm/libuinet
void
tcp_timer_keep(void *xtp)
{
	struct tcpcb *tp = xtp;
	struct tcptemp *t_template;
	struct inpcb *inp;
	CURVNET_SET(tp->t_vnet);
#ifdef TCPDEBUG
	int ostate;

	ostate = tp->t_state;
#endif
	INP_INFO_WLOCK(&V_tcbinfo);
	inp = tp->t_inpcb;
	/*
	 * XXXRW: While this assert is in fact correct, bugs in the tcpcb
	 * tear-down mean we need it as a work-around for races between
	 * timers and tcp_discardcb().
	 *
	 * KASSERT(inp != NULL, ("tcp_timer_keep: inp == NULL"));
	 */
	if (inp == NULL) {
		tcp_timer_race++;
		INP_INFO_WUNLOCK(&V_tcbinfo);
		CURVNET_RESTORE();
		return;
	}
	INP_WLOCK(inp);
	if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_keep)
	    || !callout_active(&tp->t_timers->tt_keep)) {
		INP_WUNLOCK(inp);
		INP_INFO_WUNLOCK(&V_tcbinfo);
		CURVNET_RESTORE();
		return;
	}
	callout_deactivate(&tp->t_timers->tt_keep);
	/*
	 * Keep-alive timer went off; send something
	 * or drop connection if idle for too long.
	 */
	TCPSTAT_INC(tcps_keeptimeo);
	if (tp->t_state < TCPS_ESTABLISHED)
		goto dropit;
	if ((always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
	    tp->t_state <= TCPS_CLOSING) {
		if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp))
			goto dropit;
		/*
		 * Send a packet designed to force a response
		 * if the peer is up and reachable:
		 * either an ACK if the connection is still alive,
		 * or an RST if the peer has closed the connection
		 * due to timeout or reboot.
		 * Using sequence number tp->snd_una-1
		 * causes the transmitted zero-length segment
		 * to lie outside the receive window;
		 * by the protocol spec, this requires the
		 * correspondent TCP to respond.
		 */
		TCPSTAT_INC(tcps_keepprobe);
		t_template = tcpip_maketemplate(inp);
		if (t_template) {
			tcp_respond(tp, t_template->tt_ipgen,
				    &t_template->tt_t, (struct mbuf *)NULL,
				    tp->rcv_nxt, tp->snd_una - 1, 0);
			free(t_template, M_TEMP);
		}
		callout_reset_on(&tp->t_timers->tt_keep, TP_KEEPINTVL(tp),
		    tcp_timer_keep, tp, INP_CPU(inp));
	} else
		callout_reset_on(&tp->t_timers->tt_keep, TP_KEEPIDLE(tp),
		    tcp_timer_keep, tp, INP_CPU(inp));

#ifdef TCPDEBUG
	if (inp->inp_socket->so_options & SO_DEBUG)
		tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
			  PRU_SLOWTIMO);
#endif
	INP_WUNLOCK(inp);
	INP_INFO_WUNLOCK(&V_tcbinfo);
	CURVNET_RESTORE();
	return;

dropit:
	TCPSTAT_INC(tcps_keepdrops);
	tp = tcp_drop(tp, ETIMEDOUT);

#ifdef TCPDEBUG
	if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
		tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
			  PRU_SLOWTIMO);
#endif
	if (tp != NULL)
		INP_WUNLOCK(tp->t_inpcb);
	INP_INFO_WUNLOCK(&V_tcbinfo);
	CURVNET_RESTORE();
}
コード例 #19
0
ファイル: tcp_usr.c プロジェクト: fjanssen/Car2X
int
tcp_usrreq(struct socket * so, 
   struct mbuf *  m,
   struct mbuf *  nam)
{
   struct inpcb * inp;
   struct tcpcb * tp;
   int   error =  0;
   int   req;

#ifdef DO_TCPTRACE
   int   ostate;
#endif

   req = so->so_req;    /* get request from socket struct */
   inp = sotoinpcb(so);
   /*
    * When a TCP is attached to a socket, then there will be
    * a (struct inpcb) pointed at by the socket, and this
    * structure will point at a subsidary (struct tcpcb).
    */
   if (inp == 0 && req != PRU_ATTACH) 
   {
      return (EINVAL);
   }

   if (inp)
      tp = intotcpcb(inp);
   else  /* inp and tp not set, make sure this is OK: */
   { 
      if (req == PRU_ATTACH)
         tp = NULL;  /* stifle compiler warnings about using unassigned tp*/
      else
      {
         dtrap(); /* programming error? */
         return EINVAL;
      }
   }

   switch (req) 
   {
   /*
    * TCP attaches to socket via PRU_ATTACH, reserving space,
    * and an internet control block.
    */
   case PRU_ATTACH:
      if (inp) 
      {
         error = EISCONN;
         break;
      }
      error = tcp_attach(so);
      if (error)
         break;
      if ((so->so_options & SO_LINGER) && so->so_linger == 0)
         so->so_linger = TCP_LINGERTIME;
#ifdef   DO_TCPTRACE
      SETTP(tp, sototcpcb(so));
#endif
      break;

   /*
    * PRU_DETACH detaches the TCP protocol from the socket.
    * If the protocol state is non-embryonic, then can't
    * do this directly: have to initiate a PRU_DISCONNECT,
    * which may finish later; embryonic TCB's can just
    * be discarded here.
    */
   case PRU_DETACH:
      if (tp->t_state > TCPS_LISTEN)
         SETTP(tp, tcp_disconnect(tp));
      else
         SETTP(tp, tcp_close(tp));
      break;

   /*
    * Give the socket an address.
    */
   case PRU_BIND:

      /* bind is quite different for IPv4 and v6, so we use two 
       * seperate pcbbind routines. so_domain was checked for 
       * validity way up in t_bind()
       */
#ifdef IP_V4
      if(inp->inp_socket->so_domain == AF_INET)
      {
         error = in_pcbbind(inp, nam);
         break;
      }
#endif /* IP_V4 */
#ifdef IP_V6
      if(inp->inp_socket->so_domain == AF_INET6)
      {
         error = ip6_pcbbind(inp, nam);
         break;
      }
#endif /* IP_V6 */
      dtrap();    /* not v4 or v6? */
      error = EINVAL;
      break;
   /*
    * Prepare to accept connections.
    */
   case PRU_LISTEN:
      if (inp->inp_lport == 0)
         error = in_pcbbind(inp, (struct mbuf *)0);
      if (error == 0)
         tp->t_state = TCPS_LISTEN;
      break;

   /*
    * Initiate connection to peer.
    * Create a template for use in transmissions on this connection.
    * Enter SYN_SENT state, and mark socket as connecting.
    * Start keep-alive timer, and seed output sequence space.
    * Send initial segment on connection.
    */
   case PRU_CONNECT:
      if (inp->inp_lport == 0) 
      {

#ifdef IP_V4
#ifndef IP_V6  /* v4 only */
      error = in_pcbbind(inp, (struct mbuf *)0);
#else    /* dual mode */
      if(so->so_domain == AF_INET)
         error = in_pcbbind(inp, (struct mbuf *)0);
      else
         error = ip6_pcbbind(inp, (struct mbuf *)0);
#endif   /* end dual mode code */
#else    /* no v4, v6 only */
      error = ip6_pcbbind(inp, (struct mbuf *)0);
#endif   /* end v6 only */

         if (error)
            break;
      }

#ifdef IP_V4
#ifndef IP_V6  /* v4 only */
      error = in_pcbconnect(inp, nam);
#else    /* dual mode */
      if(so->so_domain == AF_INET)
         error = in_pcbconnect(inp, nam);
      else
         error = ip6_pcbconnect(inp, nam);
#endif   /* end dual mode code */
#else    /* no v4, v6 only */
      error = ip6_pcbconnect(inp, nam);
#endif   /* end v6 only */

      if (error)
         break;
      tp->t_template = tcp_template(tp);
      if (tp->t_template == 0) 
      {

#ifdef IP_V4
#ifndef IP_V6  /* v4 only */
         in_pcbdisconnect(inp);
#else    /* dual mode */
         if(so->so_domain == AF_INET)
            in_pcbdisconnect(inp);
         else
            ip6_pcbdisconnect(inp);
#endif   /* end dual mode code */
#else    /* no v4, v6 only */
         ip6_pcbdisconnect(inp);
#endif   /* end v6 only */

         error = ENOBUFS;
         break;
      }

      soisconnecting(so);
      tcpstat.tcps_connattempt++;
      tp->t_state = TCPS_SYN_SENT;
      tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
      tp->iss = tcp_iss; 
      tcp_iss += (tcp_seq)(TCP_ISSINCR/2);
      tcp_sendseqinit(tp);
      error = tcp_output(tp);
      if (!error)
         TCP_MIB_INC(tcpActiveOpens);     /* keep MIB stats */
      break;

   /*
    * Create a TCP connection between two sockets.
    */
   case PRU_CONNECT2:
      error = EOPNOTSUPP;
      break;

   /*
    * Initiate disconnect from peer.
    * If connection never passed embryonic stage, just drop;
    * else if don't need to let data drain, then can just drop anyways,
    * else have to begin TCP shutdown process: mark socket disconnecting,
    * drain unread data, state switch to reflect user close, and
    * send segment (e.g. FIN) to peer.  Socket will be really disconnected
    * when peer sends FIN and acks ours.
    *
    * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
    */
   case PRU_DISCONNECT:
      SETTP(tp, tcp_disconnect(tp));
      break;

   /*
    * Accept a connection.  Essentially all the work is
    * done at higher levels; just return the address
    * of the peer, storing through addr.
    */
   case PRU_ACCEPT: 
   {
         struct sockaddr_in * sin   =  mtod(nam,   struct sockaddr_in *);
#ifdef IP_V6
         struct sockaddr_in6 * sin6 = mtod(nam,   struct sockaddr_in6 *);
#endif

#ifdef IP_V6
         if (so->so_domain == AF_INET6)
         {
            nam->m_len = sizeof (struct sockaddr_in6);
            sin6->sin6_port = inp->inp_fport;
            sin6->sin6_family = AF_INET6;
            IP6CPY(&sin6->sin6_addr, &inp->ip6_faddr);
         }
#endif

#ifdef IP_V4
         if (so->so_domain == AF_INET)
         {
            nam->m_len = sizeof (struct sockaddr_in);
            sin->sin_family = AF_INET;
            sin->sin_port = inp->inp_fport;
            sin->sin_addr = inp->inp_faddr;
         }
#endif
         if ( !(so->so_domain == AF_INET) &&
              !(so->so_domain == AF_INET6)
             )
         {
            dprintf("*** PRU_ACCEPT bad domain = %d\n", so->so_domain);
            dtrap();
         } 
         TCP_MIB_INC(tcpPassiveOpens);    /* keep MIB stats */
         break;
      }

   /*
    * Mark the connection as being incapable of further output.
    */
   case PRU_SHUTDOWN:
      socantsendmore(so);
      tp = tcp_usrclosed(tp);
      if (tp)
         error = tcp_output(tp);
      break;

   /*
    * After a receive, possibly send window update to peer.
    */
   case PRU_RCVD:
      (void) tcp_output(tp);
      break;

   /*
    * Do a send by putting data in output queue and updating urgent
    * marker if URG set.  Possibly send more data.
    */
   case PRU_SEND:
      if (so->so_pcb == NULL)
      {                    /* Return EPIPE error if socket is not connected */
         error = EPIPE;
         break;
      }
      sbappend(&so->so_snd, m);
      error = tcp_output(tp);
      if (error == ENOBUFS)
         sbdropend(&so->so_snd,m);  /* Remove data from socket buffer */
      break;

   /*
    * Abort the TCP.
    */
   case PRU_ABORT:
      SETTP(tp, tcp_drop(tp, ECONNABORTED));
      break;

   case PRU_SENSE:
      /*      ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat; */
      dtrap();    /* does this ever happen? */
      return (0);

   case PRU_RCVOOB:
      if ((so->so_oobmark == 0 &&
          (so->so_state & SS_RCVATMARK) == 0) ||
#ifdef SO_OOBINLINE
       so->so_options & SO_OOBINLINE ||
#endif
       tp->t_oobflags & TCPOOB_HADDATA) 
       {
         error = EINVAL;
         break;
      }
      if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) 
      {
         error = EWOULDBLOCK;
         break;
      }
      m->m_len = 1;
      *mtod(m, char *) = tp->t_iobc;
      if ((MBUF2LONG(nam) & MSG_PEEK) == 0)
         tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
      break;

   case PRU_SENDOOB:
      if (so->so_pcb == NULL)
      {                    /* Return EPIPE error if socket is not connected */
         error = EPIPE;
         break;
      }
      if (sbspace(&so->so_snd) == 0) 
      {
         m_freem(m);
         error = ENOBUFS;
         break;
      }
      /*
       * According to RFC961 (Assigned Protocols),
       * the urgent pointer points to the last octet
       * of urgent data.  We continue, however,
       * to consider it to indicate the first octet
       * of data past the urgent section.
       * Otherwise, snd_up should be one lower.
       */
      sbappend(&so->so_snd, m);
      tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
      tp->t_force = 1;
      error = tcp_output(tp);
      if (error == ENOBUFS)
         sbdropend(&so->so_snd,m);  /* Remove data from socket buffer */
      tp->t_force = 0;
      break;

   case PRU_SOCKADDR:

   /* sockaddr and peeraddr have to switch based on IP type */
#ifdef IP_V4
#ifndef IP_V6  /* v4 only */
      in_setsockaddr(inp, nam);
#else /* dual mode */
      if(so->so_domain == AF_INET6)
         ip6_setsockaddr(inp, nam);
      else
         in_setsockaddr(inp, nam);
#endif   /* dual mode */
#else    /* IP_V6 */
         ip6_setsockaddr(inp, nam);
#endif
      break;         

   case PRU_PEERADDR:
#ifdef IP_V4
#ifndef IP_V6  /* v4 only */
      in_setpeeraddr(inp, nam);
#else /* dual mode */
      if(so->so_domain == AF_INET6)
         ip6_setpeeraddr(inp, nam);
      else
         in_setpeeraddr(inp, nam);
#endif   /* dual mode */
#else    /* IP_V6 */
         ip6_setpeeraddr(inp, nam);
#endif
      break;

   case PRU_SLOWTIMO:
      SETTP(tp, tcp_timers(tp, (int)MBUF2LONG(nam)));
#ifdef DO_TCPTRACE
      req |= (long)nam << 8;        /* for debug's sake */
#endif
      break;

      default:
      panic("tcp_usrreq");
   }
#ifdef DO_TCPTRACE
   if (tp && (so->so_options & SO_DEBUG))
      tcp_trace("usrreq: state: %d, tcpcb: %x, req: %d",
    ostate, tp, req);
#endif
   return (error);
}