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sshnet: fix eof and close handling, use proper packet size, cleanup

--- a/sys/src/cmd/sshnet.c

+++ b/sys/src/cmd/sshnet.c

@@ -61,6 +61,7 @@

 	int state;

 	int num;

 	int servernum;

+	int sentclose;

 	char *connect;

 	int sendpkt;

@@ -68,6 +69,8 @@

 	int recvwin;

 	int recvacc;

+	int eof;

+

 	Req *wq;

 	Req **ewq;

@@ -91,7 +94,8 @@

 	MSG_CHANNEL_SUCCESS,

 	MSG_CHANNEL_FAILURE,

-	MaxPacket = 1<<15,

+	Overhead = 256,

+	MaxPacket = (1<<15)-256,	/* 32K is maxatomic for pipe */

 	WinPackets = 8,

 	SESSIONCHAN = 1<<24,

@@ -104,7 +108,7 @@

 	uchar	*rp;

 	uchar	*wp;

 	uchar	*ep;

-	uchar	buf[MaxPacket];

+	uchar	buf[MaxPacket + Overhead];

 };

 #define PUT4(p, u) (p)[0] = (u)>>24, (p)[1] = (u)>>16, (p)[2] = (u)>>8, (p)[3] = (u)

@@ -116,6 +120,7 @@

 int sshfd;

 int localport;

 char localip[] = "::";

+char Ehangup[] = "hangup on network connection";

 int

 vpack(uchar *p, int n, char *fmt, va_list a)

@@ -341,12 +346,10 @@

 	Msg *m;

 	int n, rm;

-	while(c->rq != nil && c->mq != nil){

-		r = c->rq;

+	while((r = c->rq) != nil && (m = c->mq) != nil){

 		c->rq = r->aux;

-

+		r->aux = nil;

 		rm = 0;

-		m = c->mq;

 		n = r->ifcall.count;

 		if(n >= m->wp - m->rp){

 			n = m->wp - m->rp;

@@ -362,6 +365,15 @@

 		respond(r, nil);

 		adjustwin(c, n);

 	}

+

+	if(c->eof){

+		while((r = c->rq) != nil){

+			c->rq = r->aux;

+			r->aux = nil;

+			r->ofcall.count = 0;

+			respond(r, nil);

+		}

+	}

 }

 void

@@ -438,57 +450,48 @@

 }

 void

-teardownclient(Client *c)

-{

-	c->state = Teardown;

-	sendmsg(pack(nil, "bu", MSG_CHANNEL_EOF, c->servernum));

-}

-

-void

 hangupclient(Client *c)

 {

-	Req *r, *next;

-	Msg *m, *mnext;

+	Req *r;

-	c->state = Closed;

-	for(m=c->mq; m; m=mnext){

-		mnext = m->link;

-		free(m);

+	c->eof = 1;

+	c->recvwin = 0;

+	c->sendwin = 0;

+	while((r = c->wq) != nil){

+		c->wq = r->aux;

+		r->aux = nil;

+		respond(r, Ehangup);

 	}

-	c->mq = nil;

-	for(r=c->rq; r; r=next){

-		next = r->aux;

-		respond(r, "hangup on network connection");

+	if(c->state == Established){

+		c->state = Teardown;

+		matchrmsgs(c);

+		return;

 	}

-	c->rq = nil;

-	for(r=c->wq; r; r=next){

-		next = r->aux;

-		respond(r, "hangup on network connection");

-	}

-	c->wq = nil;

+	c->state = Closed;

 }

 void

+teardownclient(Client *c)

+{

+	hangupclient(c);

+	if(c->sentclose++ == 0)

+		sendmsg(pack(nil, "bu", MSG_CHANNEL_CLOSE, c->servernum));

+}

+

+void

 closeclient(Client *c)

 {

-	Msg *m, *next;

+	Msg *m;

 	if(--c->ref)

 		return;

-

-	if(c->rq != nil || c->wq != nil)

-		sysfatal("ref count reached zero with requests pending (BUG)");

-

-	for(m=c->mq; m; m=next){

-		next = m->link;

+	if(c->state >= Established)

+		teardownclient(c);

+	while((m = c->mq) != nil){

+		c->mq = m->link;

 		free(m);

 	}

-	c->mq = nil;

-

-	if(c->state != Closed)

-		teardownclient(c);

 }

-

 void

 sshreadproc(void*)

@@ -810,6 +813,7 @@

 		nf = getfields(f[1], f, nelem(f), 0, "!");

 		if(nf != 2)

 			goto Badarg;

+		c->eof = 0;

 		c->sendwin = MaxPacket;

 		c->recvwin = WinPackets * MaxPacket;

 		c->recvacc = 0;

@@ -831,7 +835,7 @@

 static void

 dataread(Req *r, Client *c)

 {

-	if(c->state != Established){

+	if(c->state < Established){

 		respond(r, "not connected");

 		return;

 	}

@@ -1028,7 +1032,7 @@

 static void

 handlemsg(Msg *m)

 {

-	int chan, win, pkt, n, l;

+	int chan, win, pkt, n;

 	Client *c;

 	char *s;

@@ -1037,7 +1041,7 @@

 		if(unpack(m, "_uu", &chan, &n) < 0)

 			break;

 		c = getclient(chan);

-		if(c != nil && c->state==Established){

+		if(c != nil && c->state == Established){

 			c->sendwin += n;

 			procwreqs(c);

 		}

@@ -1046,7 +1050,9 @@

 		if(unpack(m, "_us", &chan, &s, &n) < 0)

 			break;

 		c = getclient(chan);

-		if(c != nil && c->state==Established){

+		if(c != nil && c->state == Established){

+			if(c->recvwin <= 0)

+				break;

 			c->recvwin -= n;

 			m->rp = (uchar*)s;

 			queuermsg(c, m);

@@ -1058,11 +1064,10 @@

 		if(unpack(m, "_u", &chan) < 0)

 			break;

 		c = getclient(chan);

-		if(c != nil){

-			hangupclient(c);

-			m->rp = m->wp = m->buf;

-			sendmsg(pack(m, "bu", MSG_CHANNEL_CLOSE, c->servernum));

-			return;

+		if(c != nil && c->state == Established){

+			c->eof = 1;

+			c->recvwin = 0;

+			matchrmsgs(c);

 		}

 		break;

 	case MSG_CHANNEL_CLOSE:

@@ -1069,7 +1074,7 @@

 		if(unpack(m, "_u", &chan) < 0)

 			break;

 		c = getclient(chan);

-		if(c != nil)

+		if(c != nil && c->state >= Established)

 			hangupclient(c);

 		break;

 	case MSG_CHANNEL_OPEN_CONFIRMATION:

@@ -1087,20 +1092,20 @@

 		c->sendpkt = pkt;

 		c->sendwin = win;

 		c->servernum = n;

+		c->sentclose = 0;

 		c->state = Established;

 		dialedclient(c);

 		break;

 	case MSG_CHANNEL_OPEN_FAILURE:

-		if(unpack(m, "_uus", &chan, &n, &s, &l) < 0)

+		if(unpack(m, "_u____s", &chan, &s, &n) < 0)

 			break;

 		if(chan == SESSIONCHAN){

-			sendp(ssherrchan, smprint("%.*s", utfnlen(s, l), s));

+			sendp(ssherrchan, smprint("%.*s", utfnlen(s, n), s));

 			break;

 		}

 		c = getclient(chan);

 		if(c == nil || c->state != Dialing)

 			break;

-		c->servernum = n;

 		c->state = Closed;

 		dialedclient(c);

 		break;