From 46b0c67fbbcbc663a834fd325958a1fd4e425bc2 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Mon, 25 Nov 1991 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1991-11-25

---
 port/devip.c   | 15 ++++++++++++---
 port/segment.c |  8 ++++----
 port/stil.c    | 32 +++++++++++++++++++++++---------
 port/stip.c    |  4 +++-
 4 files changed, 42 insertions(+), 17 deletions(-)

diff --git a/port/devip.c b/port/devip.c
index 33171cbff3a2ae860b1065dd984cb70e8fa3d1d8..e065e93c95dd8423a1a274916677c0fb019983b7 100644
--- a/port/devip.c
+++ b/port/devip.c
@@ -271,6 +271,13 @@ ipwrite(Chan *c, char *a, long n, ulong offset)
 			ilstart(cp, IL_ACTIVE, 20);
 
 	}
+	else if(strcmp(field[0], "disconnect") == 0) {
+		if(cp->stproto != &udpinfo)
+			error(Eperm);
+
+		cp->dst = 0;
+		cp->pdst = 0;
+	}
 	else if(strcmp(field[0], "announce") == 0) {
 		if((cp->stproto == &tcpinfo && cp->tcpctl.state != CLOSED) ||
 		   (cp->stproto == &ilinfo && cp->ilctl.state != Ilclosed))
@@ -328,7 +335,7 @@ udprcvmsg(Ipconv *muxed, Block *bp)
 {
 	Ipconv *ifc, *etab;
 	Udphdr *uh;
-	Port   dport;
+	Port   dport, sport;
 	ushort sum, len;
 	Ipaddr addr;
 
@@ -352,11 +359,13 @@ udprcvmsg(Ipconv *muxed, Block *bp)
 	}
 
 	dport = nhgets(uh->udpdport);
+	sport = nhgets(uh->udpsport);
 
 	/* Look for a conversation structure for this port */
 	etab = &muxed[conf.ip];
 	for(ifc = muxed; ifc < etab; ifc++) {
-		if(ifc->psrc == dport && ifc->ref) {
+		if(ifc->psrc == dport && ifc->ref &&
+		   (ifc->pdst == 0 || ifc->pdst == sport)) {
 			/* Trim the packet down to data size */
 			len = len - (UDP_HDRSIZE-UDP_PHDRSIZE);
 			bp = btrim(bp, UDP_EHSIZE+UDP_HDRSIZE, len);
@@ -365,7 +374,7 @@ udprcvmsg(Ipconv *muxed, Block *bp)
 
 			/* Stuff the src address into the remote file */
 		 	ifc->dst = addr;
-			ifc->pdst = nhgets(uh->udpsport);
+			ifc->pdst = sport;
 			PUTNEXT(ifc->readq, bp);
 			return;
 		}
diff --git a/port/segment.c b/port/segment.c
index e72908bb8ca4359a01a456791718d7e57b953df1..80c874b9cfd44d6739031d134493716518a8ab7b 100644
--- a/port/segment.c
+++ b/port/segment.c
@@ -339,17 +339,17 @@ ibrk(ulong addr, int seg)
 	if(s == 0)
 		errors("no segment");
 
-	qlock(&s->lk);
-
 	if(addr == 0)
 		return s->base;
 
+	qlock(&s->lk);
+
 	if(addr < s->base) {
 		/* We may start with the bss overlapping the data */
 		if(seg != BSEG || u->p->seg[DSEG] == 0 || addr < u->p->seg[DSEG]->base) {
 			qunlock(&s->lk);
-			pprint("addr below segment\n");
- 		}
+			errors("addr below segment");
+		}
 		addr = s->base;
 	}
 		
diff --git a/port/stil.c b/port/stil.c
index 0c89ab2f2f51d60f881a8c0f5ff8846fa4b14dcc..ad46eacd19de4659053b1788d4bac84fa504a4b0 100644
--- a/port/stil.c
+++ b/port/stil.c
@@ -24,15 +24,16 @@ static char *etime = "connection timed out";
 enum
 {
 	Iltickms 	= 100,
-	Slowtime 	= 20*Iltickms,
-	Fasttime 	= 5*Iltickms,
-	Acktime		= 3*Iltickms,
-	Ackkeepalive	= 1000*Iltickms,
+	Slowtime 	= 200*Iltickms,
+	Fasttime 	= 4*Iltickms,
+	Acktime		= 2*Iltickms,
+	Ackkeepalive	= 6000*Iltickms,
 	Defaultwin	= 20,
 };
 
-#define Backoff(s)	(s)*=2
 #define Starttimer(s)	{(s)->timeout = 0; (s)->fasttime = Fasttime;}
+/* Packet dropping putnext for testing */
+#define DPUTNEXT(q, b)	if((MACHP(0)->ticks&7) != 3)PUTNEXT(q, b);else{freeb(b);print(".");}
 
 void	ilrcvmsg(Ipconv*, Block*);
 void	ilackproc(void*);
@@ -43,6 +44,7 @@ void	ilpullup(Ipconv*);
 void	ilhangup(Ipconv*, char *);
 void	ilfreeq(Ilcb*);
 void	ilrexmit(Ilcb*);
+void	ilbackoff(Ilcb*);
 
 void
 ilopen(Queue *q, Stream *s)
@@ -183,8 +185,11 @@ ilackq(Ilcb *ic, Block *bp)
 	qlock(&ic->ackq);
 	if(ic->unacked)
 		ic->unackedtail->list = np;
-	else 
+	else {
+		/* Start timer since we may have been idle for some time */
+		Starttimer(ic);
 		ic->unacked = np;
+	}
 	ic->unackedtail = np;
 	qunlock(&ic->ackq);
 	np->list = 0;
@@ -673,7 +678,7 @@ ilackproc(void *a)
 			case Ilclosing:
 				if(ic->timeout >= ic->fasttime) {
 					ilsendctl(s, 0, Ilclose, ic->next, ic->recvd);
-					Backoff(ic->fasttime);
+					ilbackoff(ic);
 				}
 				if(ic->timeout >= ic->slowtime) {
 					ic->state = Ilclosed;
@@ -684,7 +689,7 @@ ilackproc(void *a)
 			case Ilsyncer:
 				if(ic->timeout >= ic->fasttime) {
 					ilsendctl(s, 0, Ilsync, ic->start, ic->recvd);
-					Backoff(ic->fasttime);
+					ilbackoff(ic);
 				}
 				if(ic->timeout >= ic->slowtime) {
 					ic->state = Ilclosed;
@@ -701,7 +706,7 @@ ilackproc(void *a)
 				}
 				if(ic->timeout >= ic->fasttime) {
 					ilrexmit(ic);
-					Backoff(ic->fasttime);
+					ilbackoff(ic);
 				}
 				if(ic->timeout >= ic->slowtime) {
 					ic->state = Ilclosed;
@@ -714,6 +719,15 @@ ilackproc(void *a)
 	}
 }
 
+void
+ilbackoff(Ilcb *ic)
+{
+	if(ic->fasttime < Slowtime/2)
+		ic->fasttime += Fasttime;
+	else
+		ic->fasttime = (ic->fasttime)*3/2;
+}
+
 void
 ilstart(Ipconv *ipc, int type, int window)
 {
diff --git a/port/stip.c b/port/stip.c
index 01d2f55cda0751d0d956443b5a28cd441501110f..63da113f98ff1f781a068d9020ac050836d08bc8 100644
--- a/port/stip.c
+++ b/port/stip.c
@@ -29,6 +29,7 @@ Queue 		*Etherq;
 Ipaddr		Myip;
 Ipaddr		Mymask;
 uchar		Netmyip[4];	/* In Network byte order */
+uchar		bcast[4] = { 0xff, 0xff, 0xff, 0xff };
 
 /* Predeclaration */
 static void	ipetherclose(Queue*);
@@ -309,7 +310,8 @@ ipetheriput(Queue *q, Block *bp)
 	}
 
 	/* Look to see if its for me before we waste time checksuming it */
-	if(memcmp(h->dst, Netmyip, sizeof(Netmyip)) != 0)
+	if(memcmp(h->dst, Netmyip, sizeof(Netmyip)) != 0 &&
+	   memcmp(h->dst, bcast, sizeof(bcast)) != 0)
 		goto drop;
 
 	if(ipcksum && ip_csum(&h->vihl)) {