From d428e767dd2429a5e9a89c9e3db122cd8840cd51 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Thu, 16 Apr 1992 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1992-04-16

---
 port/devip.c    | 66 ++++++++++++++++++++++++++++++++++++++++---------
 port/ipdat.h    |  5 ++--
 port/net.c      |  1 +
 port/tcpif.c    |  9 ++++---
 port/tcpinput.c | 58 +++++++++++++++++++++++++++++++++++++------
 5 files changed, 114 insertions(+), 25 deletions(-)

diff --git a/port/devip.c b/port/devip.c
index 9e21cbe2a3523dccf8c2fa878095d10d27f32e8e..5366b827c83d10175a3d7349404224467e18aa86 100644
--- a/port/devip.c
+++ b/port/devip.c
@@ -21,6 +21,7 @@ Ipifc	*ipifc;				/* IP protocol interfaces for stip */
 Ipconv	*ipconv[Nrprotocol];		/* Connections for each protocol */
 Network	*ipnet[Nrprotocol];		/* User level interface for protocol */
 QLock	ipalloc;			/* Protocol port allocation lock */
+Ipconv	*tcpbase;			/* Base tcp connection */
 
 /* ARPA User Datagram Protocol */
 void	udpstiput(Queue *, Block *);
@@ -171,7 +172,6 @@ ipincoming(Ipconv *base, Ipconv *from)
 				netown(new->net, new->index, u->p->user, 0);
 
 			new->ref = 1;
-			new->newcon = 0;
 			qunlock(new);
 			return new;
 		}	
@@ -262,10 +262,11 @@ ipwrite(Chan *c, char *a, long n, ulong offset)
 		cp->pdst = atoi(ctlarg[1]);
 
 		/* If we have no local port assign one */
-		qlock(&ipalloc);
-		if(cp->psrc == 0)
+		if(cp->psrc == 0){
+			qlock(&ipalloc);
 			cp->psrc = nextport(ipconv[c->dev], priv);
-		qunlock(&ipalloc);
+			qunlock(&ipalloc);
+		}
 
 		if(cp->stproto == &tcpinfo)
 			tcpstart(cp, TCP_ACTIVE, Streamhi, 0);
@@ -289,13 +290,20 @@ ipwrite(Chan *c, char *a, long n, ulong offset)
 
 		port = atoi(field[1]);
 
-		qlock(&ipalloc);
-		if(portused(ipconv[c->dev], port)) {
-			qunlock(&ipalloc);	
-			error(Einuse);
-		}
-		cp->psrc = port;
-		qunlock(&ipalloc);
+		if(port){
+			qlock(&ipalloc);
+			if(portused(ipconv[c->dev], port)) {
+				qunlock(&ipalloc);	
+				error(Einuse);
+			}
+			cp->psrc = port;
+			qunlock(&ipalloc);
+		} else if(*field[1] != '*'){
+			qlock(&ipalloc);
+			cp->psrc = nextport(ipconv[c->dev], 0);
+			qunlock(&ipalloc);
+		} else
+			cp->psrc = 0;
 
 		if(cp->stproto == &tcpinfo)
 			tcpstart(cp, TCP_PASSIVE, Streamhi, 0);
@@ -557,6 +565,8 @@ void
 tcpstopen(Queue *q, Stream *s)
 {
 	Ipconv *ipc;
+	Tcpctl *tcb;
+	Block *bp;	
 	static int tcpkprocs;
 
 	if(!Ipoutput) {
@@ -573,6 +583,8 @@ tcpstopen(Queue *q, Stream *s)
 
 	}
 
+	if(tcpbase == 0)
+		tcpbase = ipconv[s->dev];
 	ipc = &ipconv[s->dev][s->id];
 	ipc->ipinterface = newipifc(IP_TCPPROTO, tcp_input, ipconv[s->dev], 
 			            1500, 512, ETHER_HDR, "TCP");
@@ -584,6 +596,13 @@ tcpstopen(Queue *q, Stream *s)
 	RD(q)->ptr = (void *)ipc;
 	WR(q)->next->ptr = (void *)ipc->ipinterface;
 	WR(q)->ptr = (void *)ipc;
+
+	/* pass any waiting data upstream */
+	tcb = &ipc->tcpctl;
+	qlock(tcb);
+	while(bp = getb(&tcb->rcvq))
+		PUTNEXT(ipc->readq, bp);
+	qunlock(tcb);
 }
 
 void
@@ -682,6 +701,7 @@ void
 tcpstclose(Queue *q)
 {
 	Ipconv *s;
+	Ipconv *etab, *ifc;
 	Tcpctl *tcb;
 
 	s = (Ipconv *)(q->ptr);
@@ -693,10 +713,32 @@ tcpstclose(Queue *q)
 	qunlock(s);
 
 	switch(tcb->state){
-	case Closed:
 	case Listen:
+		/*
+		 *  reset any incoming calls to this listener
+		 */
+		qlock(s);
+		s->backlog = 0;
+		s->curlog = 0;
+		etab = &tcpbase[conf.ip];
+		for(ifc = tcpbase; ifc < etab; ifc++){
+			if(ifc->newcon == s) {
+				ifc->newcon = 0;
+				tcpflushincoming(ifc);
+			}
+		}
+		qunlock(s);
+
+		qlock(tcb);
+		close_self(s, 0);
+		qunlock(tcb);
+		break;
+
+	case Closed:
 	case Syn_sent:
+		qlock(tcb);
 		close_self(s, 0);
+		qunlock(tcb);
 		break;
 
 	case Syn_received:
diff --git a/port/ipdat.h b/port/ipdat.h
index 3e138b1677275d6b79617eb45e78b3ef45fc4ddb..4b4d15ac3ef91576301ea41fe5f4e86b1f190178 100644
--- a/port/ipdat.h
+++ b/port/ipdat.h
@@ -231,7 +231,7 @@ struct Tctl
 	char	flags;
 	char	tos;
 
-	Block	*rcvq;
+	Blist	rcvq;
 	ulong	rcvcnt;
 
 	Block	*sndq;			/* List of data going out */
@@ -249,8 +249,8 @@ struct Tctl
 struct Tcpctl
 {
 	QLock;
-	struct Tctl;
 	Rendez syner;
+	struct Tctl;
 };
 
 struct	Tcp
@@ -499,6 +499,7 @@ void	ipstatusfill(Chan*, char*, int);
 int	ipforme(uchar*);
 void	ipsetaddrs(void);
 int	ipconbusy(Ipconv*);
+void	tcpflushincoming(Ipconv*);
 
 #define	fmtaddr(xx)	(xx>>24)&0xff,(xx>>16)&0xff,(xx>>8)&0xff,xx&0xff
 #define	MIN(a, b)	((a) < (b) ? (a) : (b))
diff --git a/port/net.c b/port/net.c
index 011fdc267cd22a0d2a07d433e2ecefe66ffd91a0..194fd987618cd1c3ec5060f5011206de89ad128f 100644
--- a/port/net.c
+++ b/port/net.c
@@ -268,5 +268,6 @@ netown(Network *np, int id, char *o, int omode)
 void
 netdisown(Network *np, int id)
 {
+if(np == 0) panic("np == 0");
 	*np->prot[id].owner = 0;
 }
diff --git a/port/tcpif.c b/port/tcpif.c
index 830c6657b01de8138866c4f6fb7e91abeaf62f3c..ca3856aee6d8b6ec6a5cc56f8e6d6fdd777e08b5 100644
--- a/port/tcpif.c
+++ b/port/tcpif.c
@@ -46,9 +46,12 @@ state_upcall(Ipconv *s, char oldstate, char newstate)
 			qunlock(s);
 			nexterror();
 		}
-		if(s->readq == 0)
-			freeb(bp);
-		else
+		if(s->readq == 0){
+			if(newstate == Close_wait)
+				putb(&tcb->rcvq, bp);
+			else
+				freeb(bp);
+		} else
 			PUTNEXT(s->readq, bp);
 		poperror();
 		qunlock(s);
diff --git a/port/tcpinput.c b/port/tcpinput.c
index d0e9770522b5df19053af5cc21880dc0895f0db1..4a9c25aa24cfa28332749d6ad73f39077b642c6b 100644
--- a/port/tcpinput.c
+++ b/port/tcpinput.c
@@ -79,25 +79,56 @@ reset(Ipaddr source, Ipaddr dest, char tos, ushort length, Tcp *seg)
 	PUTNEXT(Ipoutput, hbp);
 }
 
+/*
+ *  flush an incoming call; send a reset to the remote side and close the
+ *  conversation
+ */
+void
+tcpflushincoming(Ipconv *s)
+{
+	Tcp seg;
+	Tcpctl *tcb;		
+
+	tcb = &s->tcpctl;
+	seg.source = s->pdst;
+	seg.dest = s->psrc;
+	seg.flags = ACK;	
+	seg.seq = tcb->snd.ptr;
+	seg.ack = tcb->last_ack = tcb->rcv.nxt;
+
+	reset(s->dst, Myip[Myself], 0, 0, &seg);
+	close_self(s, 0);
+}
+
+static void
+tcpmove(struct Tctl *to, struct Tctl *from)
+{
+	memmove(to, from, sizeof(struct Tctl));
+}
+
 Ipconv*
 tcpincoming(Ipconv *ipc, Ipconv *s, Tcp *segp, Ipaddr source)
 {
 	Ipconv *new;
 
-	if(s->curlog >= s->backlog)
+	qlock(s);
+	if(s->curlog >= s->backlog){
+		qunlock(s);
 		return 0;
+	}
 
 	new = ipincoming(ipc, s);
-	if(new == 0)
+	if(new == 0){
+		qunlock(s);
 		return 0;
+	}
 
-	qlock(s);
 	s->curlog++;
 	qunlock(s);
 	new->psrc = segp->dest;
 	new->pdst = segp->source;
 	new->dst = source;
-	memmove(&new->tcpctl, &s->tcpctl, sizeof(Tcpctl));
+	tcpmove(&new->tcpctl, &s->tcpctl);
 	new->tcpctl.flags &= ~CLONE;
 	new->tcpctl.timer.arg = new;
 	new->tcpctl.timer.state = TIMER_STOP;
@@ -269,7 +300,8 @@ tcp_input(Ipconv *ipc, Block *bp)
 
 	/* If we dont understand answer with a rst */
 	if(length)
-	if(s->readq == 0) {
+	if(s->readq == 0)
+	if(tcb->state == Closed) {
 		freeb(bp);
 		reset(source, dest, tos, length, &seg);
 		goto done;
@@ -370,9 +402,11 @@ tcp_input(Ipconv *ipc, Block *bp)
 			case Finwait2:
 				/* Place on receive queue */
 				tcb->rcvcnt += blen(bp);
-				if(bp)
-				if(s->readq) {
-					PUTNEXT(s->readq, bp);
+				if(bp){
+					if(s->readq)
+						PUTNEXT(s->readq, bp);
+					else
+						putb(&tcb->rcvq, bp);
 					bp = 0;
 				}
 				tcb->rcv.nxt += length;
@@ -811,16 +845,24 @@ init_tcpctl(Ipconv *s)
 	tcb->acktimer.arg = (void *)s;
 }
 
+/*
+ *  called with tcb locked
+ */
 void
 close_self(Ipconv *s, char reason[])
 {
 	Reseq *rp,*rp1;
 	Tcpctl *tcb = &s->tcpctl;
+	Block *bp;
 
 	stop_timer(&tcb->timer);
 	stop_timer(&tcb->rtt_timer);
 	s->err = reason;
 
+	/* flush receive queue */
+	while(bp = getb(&tcb->rcvq))
+		freeb(bp);
+
 	/* Flush reassembly queue; nothing more can arrive */
 	for(rp = tcb->reseq;rp != 0;rp = rp1){
 		rp1 = rp->next;