diff --git a/ChangeLog b/ChangeLog
index e688d4f02..c9bc5f1ff 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -159,6 +159,10 @@
      [auth2.c auth2-chall.c compat.c sshconnect2.c sshd.c]
      use buffer API and avoid static strings of fixed size; 
      ok provos@/mouring@
+   - markus@cvs.openbsd.org 2002/01/13 21:31:20
+     [channels.h nchan.c]
+     add chan_set_[io]state(), order states, state is now an u_int,
+     simplifies debugging messages; ok provos@
 
 
 20020121
@@ -7307,4 +7311,4 @@
  - Wrote replacements for strlcpy and mkdtemp
  - Released 1.0pre1
 
-$Id: ChangeLog,v 1.1768 2002/01/22 12:26:38 djm Exp $
+$Id: ChangeLog,v 1.1769 2002/01/22 12:27:11 djm Exp $
diff --git a/channels.h b/channels.h
index 40142c509..a857db11e 100644
--- a/channels.h
+++ b/channels.h
@@ -32,7 +32,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-/* RCSID("$OpenBSD: channels.h,v 1.56 2001/12/28 15:06:00 markus Exp $"); */
+/* RCSID("$OpenBSD: channels.h,v 1.57 2002/01/13 21:31:20 markus Exp $"); */
 
 #ifndef CHANNEL_H
 #define CHANNEL_H
@@ -68,8 +68,8 @@ struct Channel {
 	int     type;		/* channel type/state */
 	int     self;		/* my own channel identifier */
 	int     remote_id;	/* channel identifier for remote peer */
-	int     istate;		/* input from channel (state of receive half) */
-	int     ostate;		/* output to channel  (state of transmit half) */
+	u_int   istate;		/* input from channel (state of receive half) */
+	u_int   ostate;		/* output to channel  (state of transmit half) */
 	int     flags;		/* close sent/rcvd */
 	int     rfd;		/* read fd */
 	int     wfd;		/* write fd */
@@ -123,16 +123,16 @@ struct Channel {
 #define CHAN_X11_PACKET_DEFAULT	(CHAN_X11_WINDOW_DEFAULT/2)
 
 /* possible input states */
-#define CHAN_INPUT_OPEN			0x01
-#define CHAN_INPUT_WAIT_DRAIN		0x02
-#define CHAN_INPUT_WAIT_OCLOSE		0x04
-#define CHAN_INPUT_CLOSED		0x08
+#define CHAN_INPUT_OPEN			0
+#define CHAN_INPUT_WAIT_DRAIN		1
+#define CHAN_INPUT_WAIT_OCLOSE		2
+#define CHAN_INPUT_CLOSED		3
 
 /* possible output states */
-#define CHAN_OUTPUT_OPEN		0x10
-#define CHAN_OUTPUT_WAIT_DRAIN		0x20
-#define CHAN_OUTPUT_WAIT_IEOF		0x40
-#define CHAN_OUTPUT_CLOSED		0x80
+#define CHAN_OUTPUT_OPEN		0
+#define CHAN_OUTPUT_WAIT_DRAIN		1
+#define CHAN_OUTPUT_WAIT_IEOF		2
+#define CHAN_OUTPUT_CLOSED		3
 
 #define CHAN_CLOSE_SENT			0x01
 #define CHAN_CLOSE_RCVD			0x02
diff --git a/nchan.c b/nchan.c
index 905379b07..04266d326 100644
--- a/nchan.c
+++ b/nchan.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: nchan.c,v 1.36 2002/01/10 12:47:59 markus Exp $");
+RCSID("$OpenBSD: nchan.c,v 1.37 2002/01/13 21:31:20 markus Exp $");
 
 #include "ssh1.h"
 #include "ssh2.h"
@@ -83,6 +83,28 @@ static void	chan_send_eof2(Channel *);
 static void	chan_shutdown_write(Channel *);
 static void	chan_shutdown_read(Channel *);
 
+static char *ostates[] = { "open", "drain", "wait_ieof", "closed" };
+static char *istates[] = { "open", "drain", "wait_oclose", "closed" };
+
+static void
+chan_set_istate(Channel *c, u_int next)
+{
+	if (c->istate > CHAN_INPUT_CLOSED || next > CHAN_INPUT_CLOSED)
+		fatal("chan_set_istate: bad state %d -> %d", c->istate, next);
+	debug("channel %d: input %s -> %s", c->self, istates[c->istate],
+	    istates[next]);
+	c->istate = next;
+}
+static void
+chan_set_ostate(Channel *c, u_int next)
+{
+	if (c->ostate > CHAN_OUTPUT_CLOSED || next > CHAN_OUTPUT_CLOSED)
+		fatal("chan_set_ostate: bad state %d -> %d", c->ostate, next);
+	debug("channel %d: output %s -> %s", c->self, ostates[c->ostate],
+	    ostates[next]);
+	c->ostate = next;
+}
+
 /*
  * SSH1 specific implementation of event functions
  */
@@ -93,20 +115,17 @@ chan_rcvd_oclose1(Channel *c)
 	debug("channel %d: rcvd oclose", c->self);
 	switch (c->istate) {
 	case CHAN_INPUT_WAIT_OCLOSE:
-		debug("channel %d: input wait_oclose -> closed", c->self);
-		c->istate = CHAN_INPUT_CLOSED;
+		chan_set_istate(c, CHAN_INPUT_CLOSED);
 		break;
 	case CHAN_INPUT_OPEN:
-		debug("channel %d: input open -> closed", c->self);
 		chan_shutdown_read(c);
 		chan_send_ieof1(c);
-		c->istate = CHAN_INPUT_CLOSED;
+		chan_set_istate(c, CHAN_INPUT_CLOSED);
 		break;
 	case CHAN_INPUT_WAIT_DRAIN:
 		/* both local read_failed and remote write_failed  */
-		log("channel %d: input drain -> closed", c->self);
 		chan_send_ieof1(c);
-		c->istate = CHAN_INPUT_CLOSED;
+		chan_set_istate(c, CHAN_INPUT_CLOSED);
 		break;
 	default:
 		error("channel %d: protocol error: rcvd_oclose for istate %d",
@@ -120,9 +139,8 @@ chan_read_failed_12(Channel *c)
 	debug("channel %d: read failed", c->self);
 	switch (c->istate) {
 	case CHAN_INPUT_OPEN:
-		debug("channel %d: input open -> drain", c->self);
 		chan_shutdown_read(c);
-		c->istate = CHAN_INPUT_WAIT_DRAIN;
+		chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN);
 		break;
 	default:
 		error("channel %d: chan_read_failed for istate %d",
@@ -141,9 +159,8 @@ chan_ibuf_empty1(Channel *c)
 	}
 	switch (c->istate) {
 	case CHAN_INPUT_WAIT_DRAIN:
-		debug("channel %d: input drain -> wait_oclose", c->self);
 		chan_send_ieof1(c);
-		c->istate = CHAN_INPUT_WAIT_OCLOSE;
+		chan_set_istate(c, CHAN_INPUT_WAIT_OCLOSE);
 		break;
 	default:
 		error("channel %d: chan_ibuf_empty for istate %d",
@@ -157,12 +174,10 @@ chan_rcvd_ieof1(Channel *c)
 	debug("channel %d: rcvd ieof", c->self);
 	switch (c->ostate) {
 	case CHAN_OUTPUT_OPEN:
-		debug("channel %d: output open -> drain", c->self);
-		c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
+		chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
 		break;
 	case CHAN_OUTPUT_WAIT_IEOF:
-		debug("channel %d: output wait_ieof -> closed", c->self);
-		c->ostate = CHAN_OUTPUT_CLOSED;
+		chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
 		break;
 	default:
 		error("channel %d: protocol error: rcvd_ieof for ostate %d",
@@ -176,14 +191,12 @@ chan_write_failed1(Channel *c)
 	debug("channel %d: write failed", c->self);
 	switch (c->ostate) {
 	case CHAN_OUTPUT_OPEN:
-		debug("channel %d: output open -> wait_ieof", c->self);
 		chan_send_oclose1(c);
-		c->ostate = CHAN_OUTPUT_WAIT_IEOF;
+		chan_set_ostate(c, CHAN_OUTPUT_WAIT_IEOF);
 		break;
 	case CHAN_OUTPUT_WAIT_DRAIN:
-		debug("channel %d: output wait_drain -> closed", c->self);
 		chan_send_oclose1(c);
-		c->ostate = CHAN_OUTPUT_CLOSED;
+		chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
 		break;
 	default:
 		error("channel %d: chan_write_failed for ostate %d",
@@ -202,9 +215,8 @@ chan_obuf_empty1(Channel *c)
 	}
 	switch (c->ostate) {
 	case CHAN_OUTPUT_WAIT_DRAIN:
-		debug("channel %d: output drain -> closed", c->self);
 		chan_send_oclose1(c);
-		c->ostate = CHAN_OUTPUT_CLOSED;
+		chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
 		break;
 	default:
 		error("channel %d: internal error: obuf_empty for ostate %d",
@@ -261,8 +273,8 @@ chan_rcvd_oclose2(Channel *c)
 	c->flags |= CHAN_CLOSE_RCVD;
 	if (c->type == SSH_CHANNEL_LARVAL) {
 		/* tear down larval channels immediately */
-		c->ostate = CHAN_OUTPUT_CLOSED;
-		c->istate = CHAN_INPUT_CLOSED;
+		chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
+		chan_set_istate(c, CHAN_INPUT_CLOSED);
 		return;
 	}
 	switch (c->ostate) {
@@ -271,21 +283,18 @@ chan_rcvd_oclose2(Channel *c)
 		 * wait until a data from the channel is consumed if a CLOSE
 		 * is received
 		 */
-		debug("channel %d: output open -> drain", c->self);
-		c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
+		chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
 		break;
 	}
 	switch (c->istate) {
 	case CHAN_INPUT_OPEN:
-		debug("channel %d: input open -> closed", c->self);
 		chan_shutdown_read(c);
 		break;
 	case CHAN_INPUT_WAIT_DRAIN:
-		debug("channel %d: input drain -> closed", c->self);
 		chan_send_eof2(c);
 		break;
 	}
-	c->istate = CHAN_INPUT_CLOSED;
+	chan_set_istate(c, CHAN_INPUT_CLOSED);
 }
 static void
 chan_ibuf_empty2(Channel *c)
@@ -298,10 +307,9 @@ chan_ibuf_empty2(Channel *c)
 	}
 	switch (c->istate) {
 	case CHAN_INPUT_WAIT_DRAIN:
-		debug("channel %d: input drain -> closed", c->self);
 		if (!(c->flags & CHAN_CLOSE_SENT))
 			chan_send_eof2(c);
-		c->istate = CHAN_INPUT_CLOSED;
+		chan_set_istate(c, CHAN_INPUT_CLOSED);
 		break;
 	default:
 		error("channel %d: chan_ibuf_empty for istate %d",
@@ -313,10 +321,8 @@ static void
 chan_rcvd_ieof2(Channel *c)
 {
 	debug("channel %d: rcvd eof", c->self);
-	if (c->ostate == CHAN_OUTPUT_OPEN) {
-		debug("channel %d: output open -> drain", c->self);
-		c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
-	}
+	if (c->ostate == CHAN_OUTPUT_OPEN)
+		chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
 }
 static void
 chan_write_failed2(Channel *c)
@@ -324,14 +330,12 @@ chan_write_failed2(Channel *c)
 	debug("channel %d: write failed", c->self);
 	switch (c->ostate) {
 	case CHAN_OUTPUT_OPEN:
-		debug("channel %d: output open -> closed", c->self);
 		chan_shutdown_write(c); /* ?? */
-		c->ostate = CHAN_OUTPUT_CLOSED;
+		chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
 		break;
 	case CHAN_OUTPUT_WAIT_DRAIN:
-		debug("channel %d: output drain -> closed", c->self);
 		chan_shutdown_write(c);
-		c->ostate = CHAN_OUTPUT_CLOSED;
+		chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
 		break;
 	default:
 		error("channel %d: chan_write_failed for ostate %d",
@@ -350,9 +354,8 @@ chan_obuf_empty2(Channel *c)
 	}
 	switch (c->ostate) {
 	case CHAN_OUTPUT_WAIT_DRAIN:
-		debug("channel %d: output drain -> closed", c->self);
 		chan_shutdown_write(c);
-		c->ostate = CHAN_OUTPUT_CLOSED;
+		chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
 		break;
 	default:
 		error("channel %d: chan_obuf_empty for ostate %d",