From 6a2dd849e5264e702568476422236a91c4fd9afc Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Thu, 20 Feb 2003 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 2003-02-20

---
 ip/gre.c       |  8 +++-----
 ip/icmp.c      |  8 +++-----
 ip/icmp6.c     |  8 +++-----
 ip/il.c        |  6 ++----
 ip/ip.c        | 15 ++++++---------
 ip/ip.h        |  4 ++--
 ip/ipv6.c      |  9 +++++----
 ip/tcp.c       | 25 ++++++++++++-------------
 ip/udp.c       |  8 +++-----
 port/portfns.h |  1 +
 port/qio.c     | 29 ++++++++++++++++++++++++++---
 11 files changed, 66 insertions(+), 55 deletions(-)

diff --git a/ip/gre.c b/ip/gre.c
index 2c98cc1cebfaf346cb03a3d96c1c6bd866b87ec5..641d351bd7a709faff9240b2514a700352eb99e1 100644
--- a/ip/gre.c
+++ b/ip/gre.c
@@ -47,7 +47,7 @@ struct GREpriv
 	ulong		lenerr;			/* short packet */
 };
 
-static void grekick(void *x);
+static void grekick(void *x, Block *bp);
 
 static char*
 greconnect(Conv *c, char **argv, int argc)
@@ -90,7 +90,7 @@ static void
 grecreate(Conv *c)
 {
 	c->rq = qopen(64*1024, Qmsg, 0, c);
-	c->wq = qopen(64*1024, Qkick, grekick, c);
+	c->wq = qbypass(grekick, c);
 }
 
 static int
@@ -121,14 +121,12 @@ greclose(Conv *c)
 int drop;
 
 static void
-grekick(void *x)
+grekick(void *x, Block *bp)
 {
 	Conv *c = x;
 	GREhdr *ghp;
-	Block *bp;
 	uchar laddr[IPaddrlen], raddr[IPaddrlen];
 
-	bp = qget(c->wq);
 	if(bp == nil)
 		return;
 
diff --git a/ip/icmp.c b/ip/icmp.c
index 302669c7661babba8aa5066b8642d10c5d021bdb..7b3dc0adf28be0500169b7ae5d8e05df0263d15f 100644
--- a/ip/icmp.c
+++ b/ip/icmp.c
@@ -104,13 +104,13 @@ struct Icmppriv
 	ulong	out[Maxtype+1];
 };
 
-static void icmpkick(void *x);
+static void icmpkick(void *x, Block*);
 
 static void
 icmpcreate(Conv *c)
 {
 	c->rq = qopen(64*1024, Qmsg, 0, c);
-	c->wq = qopen(64*1024, Qkick, icmpkick, c);
+	c->wq = qbypass(icmpkick, c);
 }
 
 extern char*
@@ -157,14 +157,12 @@ icmpclose(Conv *c)
 }
 
 static void
-icmpkick(void *x)
+icmpkick(void *x, Block *bp)
 {
 	Conv *c = x;
 	Icmp *p;
-	Block *bp;
 	Icmppriv *ipriv;
 
-	bp = qget(c->wq);
 	if(bp == nil)
 		return;
 
diff --git a/ip/icmp6.c b/ip/icmp6.c
index c102b35707888ce38296be3a0db7be371f893aae..c0e0e90ce96bc38d81a4206bdabba3dc57907ca3 100644
--- a/ip/icmp6.c
+++ b/ip/icmp6.c
@@ -172,13 +172,13 @@ enum {
 	mtuopt	= 5,
 };
 
-static void icmpkick6(void *x);
+static void icmpkick6(void *x, Block *bp);
 
 static void
 icmpcreate6(Conv *c)
 {
 	c->rq = qopen(64*1024, Qmsg, 0, c);
-	c->wq = qopen(64*1024, Qkick, icmpkick6, c);
+	c->wq = qbypass(icmpkick6, c);
 }
 
 static void
@@ -228,16 +228,14 @@ icmpadvise6(Proto *icmp, Block *bp, char *msg)
 }
 
 static void
-icmpkick6(void *x)
+icmpkick6(void *x, Block *bp)
 {
 	Conv *c = x;
 	IPICMP *p;
-	Block *bp;
 	uchar laddr[IPaddrlen], raddr[IPaddrlen];
 	Icmppriv6 *ipriv = c->p->priv;
 	Icmpcb6 *icb = (Icmpcb6*)c->ptcl;
 
-	bp = qget(c->wq);
 	if(bp == nil)
 		return;
 
diff --git a/ip/il.c b/ip/il.c
index 6f618f413f5a292b8885b8151d1bffb9d48d96f3..b3bc8a1f3c24fa2dbcc98e7081a62847a35e9e94 100644
--- a/ip/il.c
+++ b/ip/il.c
@@ -335,14 +335,13 @@ ilclose(Conv *c)
 }
 
 void
-ilkick(void *x)
+ilkick(void *x, Block *bp)
 {
 	Conv *c = x;
 	Ilhdr *ih;
 	Ilcb *ic;
 	int dlen;
 	ulong id, ack;
-	Block *bp;
 	Fs *f;
 	Ilpriv *priv;
 
@@ -350,7 +349,6 @@ ilkick(void *x)
 	priv = c->p->priv;
 	ic = (Ilcb*)c->ptcl;
 
-	bp = qget(c->wq);
 	if(bp == nil)
 		return;
 
@@ -418,7 +416,7 @@ static void
 ilcreate(Conv *c)
 {
 	c->rq = qopen(64*1024, 0, 0, c);
-	c->wq = qopen(64*1024, Qkick, ilkick, c);
+	c->wq = qbypass(ilkick, c);
 }
 
 int
diff --git a/ip/ip.c b/ip/ip.c
index 5dd8b768986bcd46f8253ff793bd8a624bd08fc1..0917c2994256e7c2031236b19142a5c28d3231d5 100644
--- a/ip/ip.c
+++ b/ip/ip.c
@@ -220,7 +220,7 @@ iprouting(Fs *f, int on)
 		f->ip->stats[Forwarding] = 1;	
 }
 
-void
+int
 ipoput4(Fs *f, Block *bp, int gating, int ttl, int tos)
 {
 	Ipifc *ifc;
@@ -231,7 +231,7 @@ ipoput4(Fs *f, Block *bp, int gating, int ttl, int tos)
 	int lid, len, seglen, chunk, dlen, blklen, offset, medialen;
 	Route *r, *sr;
 	IP *ip;
-	Proto *pr;
+	int rv = 0;
 
 	ip = f->ip;
 
@@ -263,11 +263,7 @@ ipoput4(Fs *f, Block *bp, int gating, int ttl, int tos)
 	if(r == nil){
 		ip->stats[OutNoRoutes]++;
 		netlog(f, Logip, "no interface %V\n", eh->dst);
-		if(!gating){
-			freeblist(bp);
-print("ipoput4: no route\n");
-			error("no route");
-		}
+		rv = -1;
 		goto free;
 	}
 
@@ -315,7 +311,7 @@ print("ipoput4: no route\n");
 		ifc->m->bwrite(ifc, bp, V4, gate);
 		runlock(ifc);
 		poperror();
-		return;
+		return 0;
 	}
 
 if((eh->frag[0] & (IP_DF>>8)) && !gating) print("%V: DF set\n", eh->dst);
@@ -404,7 +400,8 @@ raise:
 	runlock(ifc);
 	poperror();
 free:
-	freeblist(bp);	
+	freeblist(bp);
+	return rv;
 }
 
 void
diff --git a/ip/ip.h b/ip/ip.h
index ff73780c6b71114d63752d6ec7e9496b11f4b5b7..62a46dbaccd23c67db53ec75339253bfbffe3437 100644
--- a/ip/ip.h
+++ b/ip/ip.h
@@ -620,8 +620,8 @@ extern void	icmpttlexceeded(Fs*, uchar*, Block*);
 extern ushort	ipcsum(uchar*);
 extern void	ipiput4(Fs*, Ipifc*, Block*);
 extern void	ipiput6(Fs*, Ipifc*, Block*);
-extern void	ipoput4(Fs*, Block*, int, int, int);
-extern void	ipoput6(Fs*, Block*, int, int, int);
+extern int	ipoput4(Fs*, Block*, int, int, int);
+extern int	ipoput6(Fs*, Block*, int, int, int);
 extern int	ipstats(Fs*, char*, int);
 extern ushort	ptclbsum(uchar*, int);
 extern ushort	ptclcsum(Block*, int, int);
diff --git a/ip/ipv6.c b/ip/ipv6.c
index 30f384eb6bea608f5474410faff14f97d2b92ceb..ff48390119288f0d21dbd5e6fd80133334427d2c 100644
--- a/ip/ipv6.c
+++ b/ip/ipv6.c
@@ -131,7 +131,7 @@ struct IP
 	int		iprouting;	/* true if we route like a gateway */
 };
 
-void
+int
 ipoput6(Fs *f, Block *bp, int gating, int ttl, int tos)
 {
 	int tentative;
@@ -143,7 +143,7 @@ ipoput6(Fs *f, Block *bp, int gating, int ttl, int tos)
 	Fraghdr6 fraghdr;
 	Block *xp, *nb;
 	IP *ip;
-
+	int rv = 0;
 
 	ip = f->ip;
 
@@ -184,6 +184,7 @@ ipoput6(Fs *f, Block *bp, int gating, int ttl, int tos)
 //		print("no route for %I, src %I free\n", eh->dst, eh->src);
 		ip->stats[OutNoRoutes]++;
 		netlog(f, Logip, "no interface %I\n", eh->dst);
+		rv = -1;
 		goto free;
 	}
 
@@ -228,7 +229,7 @@ ipoput6(Fs *f, Block *bp, int gating, int ttl, int tos)
 		ifc->m->bwrite(ifc, bp, V6, gate);
 		runlock(ifc);
 		poperror();
-		return;
+		return 0;
 	}
 
 	if(gating) 
@@ -328,7 +329,7 @@ raise:
 	poperror();
 free:
 	freeblist(bp);	
-
+	return rv;
 }
 
 void
diff --git a/ip/tcp.c b/ip/tcp.c
index d7578b56b173847ee5e9d3db6e84af95d7c89483..c25c3a46cad179abe15c21913ccf0d8a94411b7f 100644
--- a/ip/tcp.c
+++ b/ip/tcp.c
@@ -2411,11 +2411,6 @@ tcpoutput(Conv *s)
 	tpriv = s->p->priv;
 	version = s->ipversion;
 
-	if(waserror()){
-		localclose(s, up->errstr);
-		return;
-	}
-
 	for(msgs = 0; msgs < 100; msgs++) {
 		tcb = (Tcpctl*)s->ptcl;
 	
@@ -2423,7 +2418,7 @@ tcpoutput(Conv *s)
 		case Listen:
 		case Closed:
 		case Finwait2:
-			goto out;
+			return;
 		}
 	
 		/* force an ack when a window has opened up */
@@ -2550,7 +2545,7 @@ tcpoutput(Conv *s)
 			hbp = htontcp4(&seg, bp, &tcb->protohdr.tcp4hdr, tcb);
 			if(hbp == nil) {
 				freeblist(bp);
-				goto out;
+				return;
 			}
 			break;
 		case V6:
@@ -2558,7 +2553,7 @@ tcpoutput(Conv *s)
 			hbp = htontcp6(&seg, bp, &tcb->protohdr.tcp6hdr, tcb);
 			if(hbp == nil) {
 				freeblist(bp);
-				goto out;
+				return;
 			}
 			break;
 		default:
@@ -2590,10 +2585,16 @@ tcpoutput(Conv *s)
 
 		switch(version){
 		case V4:
-			ipoput4(f, hbp, 0, s->ttl, s->tos);
+			if(ipoput4(f, hbp, 0, s->ttl, s->tos) < 0){
+				/* a negative return means no route */
+				localclose(s, "no route");
+			}
 			break;
 		case V6:
-			ipoput6(f, hbp, 0, s->ttl, s->tos);
+			if(ipoput6(f, hbp, 0, s->ttl, s->tos) < 0){
+				/* a negative return means no route */
+				localclose(s, "no route");
+			}
 			break;
 		default:
 			panic("tcpoutput2: version %d", version);
@@ -2604,8 +2605,6 @@ tcpoutput(Conv *s)
 			qlock(s);
 		}
 	}
-out:
-	poperror();
 }
 
 /*
@@ -2745,7 +2744,7 @@ tcprxmit(Conv *s)
 	tcb->snd.ptr = tcb->snd.una;
 
 	/*
-	 *  We should be halving the slow start thershhold (down to one
+	 *  We should be halving the slow start threshhold (down to one
 	 *  mss) but leaving it at mss seems to work well enough
 	 */
  	tcb->ssthresh = tcb->mss;
diff --git a/ip/udp.c b/ip/udp.c
index fc09f3ded438eb7c05766563a16bbe8596af4b08..85ca87b425debf573d5198d5a203c24045ec8ec1 100644
--- a/ip/udp.c
+++ b/ip/udp.c
@@ -93,7 +93,7 @@ struct Udppriv
 };
 
 void (*etherprofiler)(char *name, int qlen);
-void udpkick(void *x);
+void udpkick(void *x, Block *bp);
 
 /*
  *  protocol specific part of Conv
@@ -148,7 +148,7 @@ static void
 udpcreate(Conv *c)
 {
 	c->rq = qopen(128*1024, Qmsg, 0, 0);
-	c->wq = qopen(128*1024, Qkick, udpkick, c);
+	c->wq = qbypass(udpkick, c);
 }
 
 static void
@@ -176,14 +176,13 @@ udpclose(Conv *c)
 }
 
 void
-udpkick(void *x)
+udpkick(void *x, Block *bp)
 {
 	Conv *c = x;
 	Udp4hdr *uh4;
 	Udp6hdr *uh6;
 	ushort rport;
 	uchar laddr[IPaddrlen], raddr[IPaddrlen];
-	Block *bp;
 	Udpcb *ucb;
 	int dlen, ptcllen;
 	Udppriv *upriv;
@@ -194,7 +193,6 @@ udpkick(void *x)
 	f = c->p->f;
 
 	netlog(c->p->f, Logudp, "udp: kick\n");
-	bp = qget(c->wq);
 	if(bp == nil)
 		return;
 
diff --git a/port/portfns.h b/port/portfns.h
index 1bfccea1208cf938ee0edcd5d07732bda50ce8a1..e141c8aa0ddbce1ce9915121529afd35eaeee4be 100644
--- a/port/portfns.h
+++ b/port/portfns.h
@@ -241,6 +241,7 @@ ulong		pwait(Waitmsg*);
 void		qaddlist(Queue*, Block*);
 Block*		qbread(Queue*, int);
 long		qbwrite(Queue*, Block*);
+Queue*		qbypass(void (*)(void*, Block*), void*);
 int		qcanread(Queue*);
 void		qclose(Queue*);
 int		qconsume(Queue*, void*, int);
diff --git a/port/qio.c b/port/qio.c
index 9cc79bd9f5a12b47c1d488f6fdd741b7a627017e..69234d6d5449db88ca3d86b1e662151ef656b574 100644
--- a/port/qio.c
+++ b/port/qio.c
@@ -38,6 +38,7 @@ struct Queue
 	int	eof;		/* number of eofs read by user */
 
 	void	(*kick)(void*);	/* restart output */
+	void	(*bypass)(void*, Block*);	/* bypass queue altogether */
 	void*	arg;		/* argument to kick */
 
 	QLock	rlock;		/* mutex for reading processes */
@@ -795,7 +796,6 @@ qopen(int limit, int msg, void (*kick)(void*), void *arg)
 	if(q == 0)
 		return 0;
 
-	ilock(q);
 	q->limit = q->inilim = limit;
 	q->kick = kick;
 	q->arg = arg;
@@ -804,7 +804,24 @@ qopen(int limit, int msg, void (*kick)(void*), void *arg)
 	q->state |= Qstarve;
 	q->eof = 0;
 	q->noblock = 0;
-	iunlock(q);
+
+	return q;
+}
+
+/* open a queue to be bypassed */
+Queue*
+qbypass(void (*bypass)(void*, Block*), void *arg)
+{
+	Queue *q;
+
+	q = malloc(sizeof(Queue));
+	if(q == 0)
+		return 0;
+
+	q->limit = 0;
+	q->arg = arg;
+	q->bypass = bypass;
+	q->state = 0;
 
 	return q;
 }
@@ -1143,8 +1160,14 @@ qbwrite(Queue *q, Block *b)
 	int n, dowakeup;
 	Proc *p;
 
-	dowakeup = 0;
 	n = BLEN(b);
+
+	if(q->bypass){
+		(*q->bypass)(q->arg, b);
+		return n;
+	}
+
+	dowakeup = 0;
 	qlock(&q->wlock);
 	if(waserror()){
 		if(b != nil)