When starting playback, the client tries to write ``bufsz'' frames

instead of ``appbufsz'', which violates the flow control mechanism.
Fix this longstanding bug by enabling negative values in AMSG_MOVE
messages, this way the client is notified when its stream is
attached to the mixer, and can update its max transfer limit.

Since this fix changes the AMSG_MOVE message format, we crank the
protocol version, and thus remove code specific to the old protocol.

3 files changed, 30 insertions, 48 deletions

diff --git a/lib/libsndio/aucat.c b/lib/libsndio/aucat.c
index cc1e977b1f1..681411700de 100644
--- a/lib/libsndio/aucat.c
+++ b/lib/libsndio/aucat.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: aucat.c,v 1.29 2009/10/17 10:55:43 ratchov Exp $	*/
+/*	$OpenBSD: aucat.c,v 1.30 2009/10/22 21:41:30 ratchov Exp $	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -43,6 +43,9 @@ struct aucat_hdl {
 	int maxwrite;			/* latency constraint */
 	int events;			/* events the user requested */
 	unsigned curvol, reqvol;	/* current and requested volume */
+	unsigned devbufsz;		/* server side buffer size (in frames) */
+	unsigned attached;		/* stream attached to device */
+	int delta;			/* some of received deltas */
 };
 
 static void aucat_close(struct sio_hdl *);
@@ -150,8 +153,17 @@ aucat_runmsg(struct aucat_hdl *hdl)
 		hdl->rtodo = hdl->rmsg.u.data.size;
 		break;
 	case AMSG_MOVE:
-		hdl->maxwrite += hdl->rmsg.u.ts.delta * (int)hdl->wbpf;
-		sio_onmove_cb(&hdl->sio, hdl->rmsg.u.ts.delta);
+		if (!hdl->attached) {
+			DPRINTF("aucat_runmsg: attached\n");
+			hdl->maxwrite += hdl->devbufsz * hdl->wbpf;
+			hdl->attached = 1;
+		}
+		hdl->delta += hdl->rmsg.u.ts.delta;
+		if (hdl->delta >= 0) {
+			hdl->maxwrite += hdl->delta * hdl->wbpf;
+			sio_onmove_cb(&hdl->sio, hdl->delta);
+			hdl->delta = 0;
+		}
 		hdl->rstate = STATE_MSG;
 		hdl->rtodo = sizeof(struct amsg);
 		break;
@@ -303,7 +315,10 @@ aucat_start(struct sio_hdl *sh)
 		return 0;
 	hdl->wbpf = par.bps * par.pchan;
 	hdl->rbpf = par.bps * par.rchan;
-	hdl->maxwrite = hdl->wbpf * par.bufsz;
+	hdl->maxwrite = hdl->wbpf * par.appbufsz;
+	hdl->devbufsz = par.bufsz - par.appbufsz;
+	hdl->attached = 0;
+	hdl->delta = 0;
 
 	AMSG_INIT(&hdl->wmsg);
 	hdl->wmsg.cmd = AMSG_START;
diff --git a/usr.bin/aucat/amsg.h b/usr.bin/aucat/amsg.h
index 9492f2bb8d1..fa971543c30 100644
--- a/usr.bin/aucat/amsg.h
+++ b/usr.bin/aucat/amsg.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: amsg.h,v 1.11 2009/10/17 10:55:43 ratchov Exp $	*/
+/*	$OpenBSD: amsg.h,v 1.12 2009/10/22 21:41:30 ratchov Exp $	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -89,7 +89,7 @@ struct amsg {
 #define AMSG_MIDIOUT	0x8			/* MIDI thru output */
 #define AMSG_MIXER	0x10			/* MIDI mixer */
 			uint16_t proto;		/* protocol type */
-#define AMSG_VERSION	0
+#define AMSG_VERSION	1
 			uint8_t version;	/* protocol version */
 			uint8_t reserved1[5];	/* for future use */
 			char opt[12];		/* profile name */
diff --git a/usr.bin/aucat/sock.c b/usr.bin/aucat/sock.c
index 5248d8b3528..0611755a477 100644
--- a/usr.bin/aucat/sock.c
+++ b/usr.bin/aucat/sock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sock.c,v 1.32 2009/10/21 05:43:41 ratchov Exp $	*/
+/*	$OpenBSD: sock.c,v 1.33 2009/10/22 21:41:30 ratchov Exp $	*/
 /*
  * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
  *
@@ -130,13 +130,6 @@ rsock_opos(struct aproc *p, struct abuf *obuf, int delta)
 		return;
 
 	f->delta += delta;
-	/*
-	 * Negative deltas are xrun notifications for internal uses
-	 * only. Don't generate a packet for this, the client will be
-	 * notified later.
-	 */
-	if (delta < 0)
-		return;
 	f->tickpending++;
 	for (;;) {
 		if (!sock_write(f))
@@ -228,14 +221,7 @@ wsock_ipos(struct aproc *p, struct abuf *obuf, int delta)
 		return;
 
 	f->delta += delta;
-	/*
-	 * Negative deltas are xrun notifications for internal uses
-	 * only. Don't generate a packet for this, the client will be
-	 * notified later.
-	 */
-	if (delta < 0)
-		return;
-	f->tickpending++;	
+	f->tickpending++;
 	for (;;) {
 		if (!sock_write(f))
 			break;
@@ -550,21 +536,6 @@ sock_setpar(struct sock *f)
 	struct amsg_par *p = &f->rmsg.u.par;
 	unsigned min, max, rate;
 
-	if (AMSG_ISSET(p->legacy_mode)) {
-		/*
-		 * allow old clients that don't support HELLO to work
-		 * XXX: remove this.
-		 */
-		if ((p->legacy_mode & ~(AMSG_PLAY | AMSG_REC)) ||
-		    (p->legacy_mode == 0)) {
-			return 0;
-		}
-		f->mode = 0;
-		if ((p->legacy_mode & AMSG_PLAY) && dev_mix)
-			f->mode |= AMSG_PLAY;
-		if ((p->legacy_mode & AMSG_REC) && dev_sub)
-			f->mode |= AMSG_REC;
-	}
 	if (AMSG_ISSET(p->bits)) {
 		if (p->bits < BITS_MIN || p->bits > BITS_MAX) {
 			return 0;
@@ -674,9 +645,12 @@ sock_hello(struct sock *f)
 {
 	struct amsg_hello *p = &f->rmsg.u.hello;
 
-	/* XXX : set file name to p->who */
-	/* XXX : dev_midi can no longer be NULL, right ? */
-
+	if (p->version != AMSG_VERSION) {
+		return 0;
+	}
+	/*
+	 * XXX : dev_midi can no longer be NULL, right ?
+	 */
 	if (dev_midi && (p->proto & (AMSG_MIDIIN | AMSG_MIDIOUT))) {
 		if (p->proto & ~(AMSG_MIDIIN | AMSG_MIDIOUT)) {
 			return 0;
@@ -729,13 +703,6 @@ sock_execmsg(struct sock *f)
 {
 	struct amsg *m = &f->rmsg;
 
-	/*
-	 * XXX: allow old clients to work without hello on the default socket
-	 */
-	if (f->pstate == SOCK_HELLO && m->cmd != AMSG_HELLO && f->opt != NULL) {
-		f->pstate = SOCK_INIT;
-	}
-
 	switch (m->cmd) {
 	case AMSG_DATA:
 		if (f->pstate != SOCK_RUN && f->pstate != SOCK_START) {
@@ -899,7 +866,7 @@ sock_buildmsg(struct sock *f)
 	/*
 	 * If pos changed, build a MOVE message.
 	 */
-	if (f->tickpending && f->delta >= 0) {
+	if (f->tickpending) {
 		AMSG_INIT(&f->wmsg);
 		f->wmsg.cmd = AMSG_MOVE;
 		f->wmsg.u.ts.delta = f->delta;