From fd2b7c0db9aa3256c498007e41359bdfc066a9e4 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Thu, 18 Feb 1993 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1993-02-18

---
 port/ipdat.h     | 8 ++++----
 port/tcpinput.c  | 9 ++++++---
 port/tcpoutput.c | 8 ++++----
 3 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/port/ipdat.h b/port/ipdat.h
index 7ec2de425198ef4de2c7cedec6bfb581dc43d37b..a82378f16a0ff289e00e013c761fe68bccf2b135 100644
--- a/port/ipdat.h
+++ b/port/ipdat.h
@@ -217,7 +217,7 @@ struct Tctl
 		int	wl2;
 	} snd;
 	struct {
-		int	nxt;		/* Receive pointer to next byte slot */
+		ulong	nxt;		/* Receive pointer to next byte slot */
 		ushort	wnd;		/* Receive window incoming */
 		int	up;		/* Urgent pointer */
 	} rcv;
@@ -230,7 +230,7 @@ struct Tctl
 	int	rerecv;			/* Overlap of data rerecevived */
 	ushort	window;			/* Recevive window */
 	int	max_snd;		/* Max send */
-	int	last_ack;		/* Last acknowledege received */
+	ulong	last_ack;		/* Last acknowledege received */
 	char	backoff;		/* Exponential backoff counter */
 	char	flags;			/* State flags */
 	char	tos;			/* Type of service */
@@ -311,7 +311,7 @@ struct Ipconv
 enum
 {
 	MAX_TIME 	= (1<<20),	/* Forever */
-	TCP_ACK		= 200,		/* Timed ack sequence every 200ms */
+	TCP_ACK		= 50,		/* Timed ack sequence in ms */
 
 	URG		= 0x20,		/* Data marked urgent */
 	ACK		= 0x10,		/* Aknowledge is valid */
@@ -326,7 +326,7 @@ enum
 
 	MSS_LENGTH	= 4,		/* Mean segment size */
 	MSL2		= 10,
-	MSPTICK		= 100,		/* Milliseconds per timer tick */
+	MSPTICK		= 50,		/* Milliseconds per timer tick */
 	DEF_MSS		= 1024,		/* Default mean segment */
 	DEF_RTT		= 1000,		/* Default round trip */
 
diff --git a/port/tcpinput.c b/port/tcpinput.c
index 8ccfa69af86ca86b932659cfb93b697a6a9b3036..cb33bcab11b96828bf1a2b2b4cd8d7b0e5f3ecb0 100644
--- a/port/tcpinput.c
+++ b/port/tcpinput.c
@@ -84,7 +84,8 @@ tcpflushincoming(Ipconv *s)
 	seg.dest = s->psrc;
 	seg.flags = ACK;	
 	seg.seq = tcb->snd.ptr;
-	seg.ack = tcb->last_ack = tcb->rcv.nxt;
+	tcb->last_ack = tcb->rcv.nxt;
+	seg.ack = tcb->rcv.nxt;
 
 	sndrst(s->dst, Myip[Myself], 0, &seg);
 	localclose(s, 0);
@@ -409,10 +410,12 @@ tcpinput(Ipifc *ifc, Block *bp)
 
 				tcprcvwin(s);
 	
-				tcpgo(&tcb->acktimer);
+				if(tcb->acktimer.state != TimerON)
+					tcpgo(&tcb->acktimer);
 
-				if(tcb->max_snd <= tcb->rcv.nxt-tcb->last_ack)
+				if(tcb->rcv.nxt-tcb->last_ack > Streamhi/2)
 					tcb->flags |= FORCE;
+
 				break;
 			case Finwait2:
 				/* no process to read the data, send a reset */
diff --git a/port/tcpoutput.c b/port/tcpoutput.c
index bbb1f7ee60ef5fcb87b5451289f506914e517077..41dd8d11e366703ad5e784e4574d1d5b816f0a04 100644
--- a/port/tcpoutput.c
+++ b/port/tcpoutput.c
@@ -46,10 +46,9 @@ tcpoutput(Ipconv *s)
 		 */
 		if(tcb->snd.wnd == 0){
 			if(sent != 0) {
-				if (tcb->flags&FORCE)
-						tcb->snd.ptr = tcb->snd.una;
-				else
+				if ((tcb->flags&FORCE) == 0)
 					break;
+				tcb->snd.ptr = tcb->snd.una;
 			}
 			usable = 1;
 		}
@@ -92,8 +91,9 @@ tcpoutput(Ipconv *s)
 			}
 			break;
 		}
+		tcb->last_ack = tcb->rcv.nxt;
 		seg.seq = tcb->snd.ptr;
-		seg.ack = tcb->last_ack = tcb->rcv.nxt;
+		seg.ack = tcb->rcv.nxt;
 		seg.wnd = tcb->rcv.wnd;
 
 		/* Pull out data to send */