From 02670acd63473f06aa8fd30fa422a7dd8a6fd257 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Wed, 20 Dec 2000 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 2000-12-20

---
 ip/devip.c   | 27 +++++++++++++++++++--------
 ip/esp.c     |  2 --
 ip/gre.c     |  2 --
 ip/icmp.c    |  1 -
 ip/il.c      |  1 -
 ip/ip.h      |  1 +
 ip/ipifc.c   | 14 ++++----------
 ip/ipmux.c   |  2 --
 ip/rudp.c    |  1 -
 ip/tcp.c     | 30 ++++++++++++------------------
 ip/udp.c     | 12 +++++-------
 port/error.h |  1 +
 12 files changed, 42 insertions(+), 52 deletions(-)

diff --git a/ip/devip.c b/ip/devip.c
index 256b2fe31539f8d2dfbbeb07ddb69cd3fc059eac..a62b266e71476efbda0bdc0dd161dce38ecb19f2 100644
--- a/ip/devip.c
+++ b/ip/devip.c
@@ -501,8 +501,9 @@ closeconv(Conv *cv)
 	while((mp = cv->multi) != nil)
 		ipifcremmulti(cv, mp->ma, mp->ia);
 
-	/* The close routine will unlock the conv */
 	cv->p->close(cv);
+	cv->state = Idle;
+	qunlock(cv);
 }
 
 static void
@@ -789,6 +790,8 @@ connectctlmsg(Proto *x, Conv *c, Cmdbuf *cb)
 {
 	char *p;
 
+	if(c->state != 0)
+		error(Econinuse);
 	c->state = Connecting;
 	c->cerr[0] = '\0';
 	if(x->connect == nil)
@@ -796,7 +799,11 @@ connectctlmsg(Proto *x, Conv *c, Cmdbuf *cb)
 	p = x->connect(c, cb->f, cb->nf);
 	if(p != nil)
 		error(p);
+	qunlock(c);
+
 	sleep(&c->cr, connected, c);
+
+	qlock(c);
 	if(c->cerr[0] != '\0')
 		error(c->cerr);
 }
@@ -830,6 +837,8 @@ announcectlmsg(Proto *x, Conv *c, Cmdbuf *cb)
 {
 	char *p;
 
+	if(c->state != 0)
+		error(Econinuse);
 	c->state = Announcing;
 	c->cerr[0] = '\0';
 	if(x->announce == nil)
@@ -837,7 +846,11 @@ announcectlmsg(Proto *x, Conv *c, Cmdbuf *cb)
 	p = x->announce(c, cb->f, cb->nf);
 	if(p != nil)
 		error(p);
+	qunlock(c);
+
 	sleep(&c->cr, announced, c);
+
+	qlock(c);
 	if(c->cerr[0] != '\0')
 		error(c->cerr);
 }
@@ -934,12 +947,9 @@ ipwrite(Chan* ch, void *v, long n, vlong off)
 		c = x->conv[CONV(ch->qid)];
 		cb = parsecmd(a, n);
 
-		if(canqlock(&c->car) == 0){
-			free(cb);
-			error("connect/announce in progress");
-		}
+		qlock(c);
 		if(waserror()) {
-			qunlock(&c->car);
+			qunlock(c);
 			free(cb);
 			nexterror();
 		}
@@ -983,7 +993,7 @@ ipwrite(Chan* ch, void *v, long n, vlong off)
 				error(p);
 		} else
 			error("unknown control request");
-		qunlock(&c->car);
+		qunlock(c);
 		free(cb);
 		poperror();
 	}
@@ -1129,7 +1139,7 @@ retry:
 	c->inuse = 1;
 	strcpy(c->owner, user);
 	c->perm = 0660;
-	c->state = 0;
+	c->state = Idle;
 	ipmove(c->laddr, IPnoaddr);
 	ipmove(c->raddr, IPnoaddr);
 	c->lport = 0;
@@ -1211,6 +1221,7 @@ Fsnewcall(Conv *c, uchar *raddr, ushort rport, uchar *laddr, ushort lport)
 	nc->lport = lport;
 	nc->next = nil;
 	*l = nc;
+	c->state = Connected;
 	qunlock(c);
 
 	wakeup(&c->listenr);
diff --git a/ip/esp.c b/ip/esp.c
index 399c91b0ece921087bb55fcef763977289bc2149..6f5703a28eaf1cd70150a288e8ccc743cec00af7 100644
--- a/ip/esp.c
+++ b/ip/esp.c
@@ -219,8 +219,6 @@ espclose(Conv *c)
 	free(ecb->espstate);
 	free(ecb->ahstate);
 	memset(ecb, 0, sizeof(Espcb));
-	
-	qunlock(c);
 }
 
 void
diff --git a/ip/gre.c b/ip/gre.c
index 50b4036cfc40eed0902a60e339bccad8ec4aa084..6ff233424dd8967c44a1fb91994258a57cac1f95 100644
--- a/ip/gre.c
+++ b/ip/gre.c
@@ -114,8 +114,6 @@ greclose(Conv *c)
 	ipmove(c->raddr, IPnoaddr);
 	c->lport = 0;
 	c->rport = 0;
-
-	qunlock(c);
 }
 
 int drop;
diff --git a/ip/icmp.c b/ip/icmp.c
index 3285e615b03eec696f6059d7181c866ad5919a08..9b2fb4f8a7a58400aadb15c507b0d6b1613f2db7 100644
--- a/ip/icmp.c
+++ b/ip/icmp.c
@@ -145,7 +145,6 @@ icmpclose(Conv *c)
 	ipmove(c->laddr, IPnoaddr);
 	ipmove(c->raddr, IPnoaddr);
 	c->lport = 0;
-	qunlock(c);
 }
 
 static void
diff --git a/ip/il.c b/ip/il.c
index facf2425cf2b057fa9f7656a24dc9c66977e4be4..e5944b1c2f195f98b90bb3d3e2b43e0315ec1a34 100644
--- a/ip/il.c
+++ b/ip/il.c
@@ -304,7 +304,6 @@ ilclose(Conv *c)
 		break;
 	}
 	ilfreeq(ic);
-	qunlock(c);
 }
 
 void
diff --git a/ip/ip.h b/ip/ip.h
index f6cc73df1d13403f925d8fa9f061486736ffef72..e3cfc02273e7b2882f9565d554531087563efa9a 100644
--- a/ip/ip.h
+++ b/ip/ip.h
@@ -48,6 +48,7 @@ enum
 
 enum
 {
+	Idle=		0,
 	Announcing=	1,
 	Announced=	2,
 	Connecting=	3,
diff --git a/ip/ipifc.c b/ip/ipifc.c
index a4dc34097654f33d45a08d5281df692d2a4591f0..54e18eb001bc3177c9e0ff836e2f433185f83a0e 100644
--- a/ip/ipifc.c
+++ b/ip/ipifc.c
@@ -99,7 +99,7 @@ ipfindmedium(char *name)
 
 /*
  *  attach a device (or pkt driver) to the interface.
- *  called with c->car locked
+ *  called with c locked
  */
 static char*
 ipifcbind(Conv *c, char **argv, int argc)
@@ -136,11 +136,8 @@ ipifcbind(Conv *c, char **argv, int argc)
 	ifc->m = m;
 	ifc->minmtu = ifc->m->minmtu;
 	ifc->maxmtu = ifc->m->maxmtu;
-	if(ifc->m->unbindonclose == 0){
-		qlock(ifc->conv);
+	if(ifc->m->unbindonclose == 0)
 		ifc->conv->inuse++;
-		qunlock(ifc->conv);
-	}
 	ifc->ifcid++;
 
 	wunlock(ifc);
@@ -151,6 +148,7 @@ ipifcbind(Conv *c, char **argv, int argc)
 
 /*
  *  detach a device from an interface, close the interface
+ *  called with ifc->conv closed
  */
 static char*
 ipifcunbind(Ipifc *ifc)
@@ -166,11 +164,8 @@ ipifcunbind(Ipifc *ifc)
 	wlock(ifc);
 
 	/* dissociate routes */
-	if(ifc->m != nil && ifc->m->unbindonclose == 0){
-		qlock(ifc->conv);
+	if(ifc->m != nil && ifc->m->unbindonclose == 0)
 		ifc->conv->inuse--;
-		qunlock(ifc->conv);
-	}
 	ifc->ifcid++;
 
 	/* disassociate device */
@@ -309,7 +304,6 @@ ipifcclose(Conv *c)
 	m = ifc->m;
 	if(m != nil && m->unbindonclose)
 		ipifcunbind(ifc);
-	qunlock(c);
 }
 
 /*
diff --git a/ip/ipmux.c b/ip/ipmux.c
index ba5e8b3dbc32566b3014ff5794b9af35dca0a329..cf91da6ccb3b41fd7ef5090d2027f61571545703 100644
--- a/ip/ipmux.c
+++ b/ip/ipmux.c
@@ -619,8 +619,6 @@ ipmuxclose(Conv *c)
 	wunlock(f);
 	ipmuxtreefree(r->chain);
 	r->chain = nil;
-
-	qunlock(c);
 }
 
 /*
diff --git a/ip/rudp.c b/ip/rudp.c
index 3dda3da3cdefccee7cf7975aeae3bf43f0d03880..a704c9709217fd23ca5b1109b59a8426974301f6 100644
--- a/ip/rudp.c
+++ b/ip/rudp.c
@@ -296,7 +296,6 @@ rudpclose(Conv *c)
 	ucb->r = 0;
 
 	qunlock(ucb);
-	qunlock(c);
 }
 
 /*
diff --git a/ip/tcp.c b/ip/tcp.c
index ab0fa509664819f03f584eb7b2187dace03cc397..62dcf35cd1c213e3319b3f2aa98ea8ac01d410ad 100644
--- a/ip/tcp.c
+++ b/ip/tcp.c
@@ -402,7 +402,6 @@ tcpclose(Conv *c)
 		tcpoutput(c);
 		break;
 	}
-	qunlock(c);
 }
 
 void
@@ -412,6 +411,11 @@ tcpkick(Conv *s, int len)
 
 	tcb = (Tcpctl*)s->ptcl;
 
+	if(waserror()){
+		qunlock(s);
+		nexterror();
+	}
+	qlock(s);
 
 	switch(tcb->state) {
 	case Listen:
@@ -426,22 +430,17 @@ tcpkick(Conv *s, int len)
 		/*
 		 * Push data
 		 */
-		if(waserror()){
-			qunlock(s);
-			nexterror();
-		}
-		qlock(s);
 		tcb->sndcnt += len;
 		tcprcvwin(s);
 		tcpoutput(s);
-		qunlock(s);
-		poperror();
 		break;
 	default:
-		qlock(s);
 		localclose(s, "Hangup");
-		qunlock(s);
+		break;
 	}
+
+	qunlock(s);
+	poperror();
 }
 
 void
@@ -682,6 +681,9 @@ inittcpctl(Conv *s)
 	tcb->mss = tcb->cwind = tcpmtu(s);
 }
 
+/*
+ *  called with s qlocked
+ */
 void
 tcpstart(Conv *s, int mode, ushort window)
 {
@@ -703,13 +705,7 @@ tcpstart(Conv *s, int mode, ushort window)
 
 	tcb = (Tcpctl*)s->ptcl;
 
-	qlock(s);
 	/* Send SYN, go into SYN_SENT state */
-	if(waserror()){
-		qunlock(s);
-		nexterror();
-	}
-
 	inittcpctl(s);
 	tcb->window = window;
 	tcb->rcv.wnd = window;
@@ -729,8 +725,6 @@ tcpstart(Conv *s, int mode, ushort window)
 		tcpoutput(s);
 		break;
 	}
-	qunlock(s);
-	poperror();
 }
 
 static char*
diff --git a/ip/udp.c b/ip/udp.c
index 209f4fbaaf0621da4f1885523bd87bf8f80960fd..003fc1a76006f4e80b56580d6451eb10422bb5df 100644
--- a/ip/udp.c
+++ b/ip/udp.c
@@ -140,8 +140,6 @@ udpclose(Conv *c)
 
 	ucb = (Udpcb*)c->ptcl;
 	ucb->headers = 0;
-
-	qunlock(c);
 }
 
 void
@@ -404,22 +402,22 @@ found:
 
 }
 
-/* close any incoming calls waiting on this conversation */
+/*
+ *  close any incoming calls waiting on this conversation
+ *  	called with c locked
+ */
 void
 udpcloseincalls(Conv *c)
 {
 	Conv *nc;
 
-	qlock(c);
-
 	for(nc = c->incall; nc; nc = c->incall){
 		c->incall = nc->next;
 		closeconv(nc);
 	}
-
-	qunlock(c);
 }
 
+/* called with c locked */
 char*
 udpctl(Conv *c, char **f, int n)
 {
diff --git a/port/error.h b/port/error.h
index 4cf4554a762855eb64d483f85da1a58bcc3e6aa9..9c90b6afe865b306700c377cc527ce5c1eb9bd33 100644
--- a/port/error.h
+++ b/port/error.h
@@ -33,6 +33,7 @@ extern char Eisstream[];	/* seek on a stream */
 extern char Ebadexec[];		/* exec header invalid */
 extern char Etimedout[];	/* connection timed out */
 extern char Econrefused[];	/* connection refused */
+extern char Econinuse[];	/* connection in use */
 extern char Eintr[];		/* interrupted */
 extern char Enomem[];		/* kernel allocate failed */
 extern char Enoswap[];		/* swap space full */