From 8ce307a603cb7279974fff7f895355161550806f Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Thu, 31 May 2001 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 2001-05-31

---
 bitsy/devsac.c | 87 +++++++++++++++++++++++++++++++++++++-------------
 ip/tcp.c       |  8 +++--
 2 files changed, 71 insertions(+), 24 deletions(-)

diff --git a/bitsy/devsac.c b/bitsy/devsac.c
index eec750c25453bac9fad2ba9d0258ae76e3d3378a..dcf0da2b78ae86a46d7fc11d7ca4cf8b4f033a75 100644
--- a/bitsy/devsac.c
+++ b/bitsy/devsac.c
@@ -6,6 +6,20 @@
 #include "io.h"
 #include "../port/error.h"
 
+/*
+ *  definitions from the old 9P.  we need these because sac files
+ *  are encoded using the old definitions.
+ */
+#define NAMELEN		28
+
+#define CHDIR		0x80000000	/* mode bit for directories */
+#define CHAPPEND	0x40000000	/* mode bit for append only files */
+#define CHEXCL		0x20000000	/* mode bit for exclusive use files */
+#define CHMOUNT		0x10000000	/* mode bit for mounted channel */
+#define CHREAD		0x4		/* mode bit for read permission */
+#define CHWRITE		0x2		/* mode bit for write permission */
+#define CHEXEC		0x1		/* mode bit for execute permission */
+
 enum
 {
 	OPERM	= 0x3,		/* mask of all permission types in open mode */
@@ -26,9 +40,9 @@ enum {
 
 struct SacDir
 {
-	char	name[KNAMELEN];
-	char	uid[KNAMELEN];
-	char	gid[KNAMELEN];
+	char	name[NAMELEN];
+	char	uid[NAMELEN];
+	char	gid[NAMELEN];
 	uchar	qid[4];
 	uchar	mode[4];
 	uchar	atime[4];
@@ -93,6 +107,17 @@ static int sacdirread(Chan *, char *p, long off, long cnt);
 static void loadblock(void *buf, uchar *offset, int blocksize);
 static void sacfree(Sac*);
 
+static void
+pathtoqid(ulong path, Qid *q)
+{
+	if(path & CHDIR)
+		q->type = QTDIR;
+	else
+		q->type = QTFILE;
+	q->path = path & ~(CHDIR|CHAPPEND|CHEXCL|CHMOUNT);
+	q->vers = 0;
+}
+
 static void
 sacinit(void)
 {
@@ -139,12 +164,7 @@ sacattach(char* spec)
 
 	c = devattach('C', spec);
 	path = getl(root.qid);
-	if(path & CHDIR)
-		c->qid.type = QTDIR;
-	else
-		c->qid.type = QTFILE;
-	c->qid.path = path & ~CHDIR;
-	c->qid.vers = 0;
+	pathtoqid(path, &c->qid;
 	c->dev = dev;
 	c->aux = saccpy(&root);
 	return c;
@@ -158,24 +178,47 @@ sacclone(Chan *c, Chan *nc)
 	return nc;
 }
 
-static int
-sacwalk(Chan *c, char *name)
+static Walkqid*
+sacwalk(Chan *c, Chan *nc, char **name, int nname)
 {
 	Sac *sac;
+	int i, j, alloc;
+	Walkqid *wq;
+	char *n;
+	Dir dir;
 
-//print("walk %s\n", name);
+	if(nname > 0)
+		isdir(c);
 
-	isdir(c);
-	if(name[0]=='.' && name[1]==0)
-		return 1;
-	sac = c->aux;
-	sac = saclookup(sac, name);
-	if(sac == nil) {
-		strncpy(up->error, Enonexist, NAMELEN);
-		return 0;
+	alloc = 0;
+	wq = smalloc(sizeof(Walkqid)+(nname-1)*sizeof(Qid));
+	if(waserror()){
+		if(alloc && wq->clone!=nil)
+			cclose(wq->clone);
+		free(wq);
+		return nil;
+	}
+	if(nc == nil){
+		nc = devclone(c);
+		nc->type = 0;	/* device doesn't know about this channel yet */
+		alloc = 1;
+	}
+	wq->clone = nc;
+
+	for(j=0; j<nname; j++){
+		isdir(nc);
+
+		if(name[0]=='.' && name[1]==0)
+			return 1;
+		sac = nc->aux;
+		sac = saclookup(sac, name);
+		if(sac == nil) {
+			strncpy(up->error, Enonexist, NAMELEN);
+			return 0;
+		}
+		nc->aux = sac;
+		pathtoqid(getl(sac->qid), &nc->qid);
 	}
-	c->aux = sac;
-	c->qid = (Qid){getl(sac->qid), 0};
 	return 1;
 }
 
diff --git a/ip/tcp.c b/ip/tcp.c
index 589c8a867f1f6c16b83b24e75359e79b71dc40a1..551d79896af486a5af29016e2f601d54a5e85cc1 100644
--- a/ip/tcp.c
+++ b/ip/tcp.c
@@ -1102,8 +1102,10 @@ update(Conv *s, Tcp *seg)
 	}
 
 	/* added by Dong for fast retransmission */
-	if( seg->ack == tcb->snd.una &&
-	    seg->len == 0 && seg->wnd == tcb->snd.wnd ) {
+	if(seg->ack == tcb->snd.una
+	&& tcb->snd.una != tcb->snd.nxt
+	&& seg->len == 0
+	&& seg->wnd == tcb->snd.wnd) {
 
 		/* this is a pure ack w/o window update */
 		netlog(s->p->f, Logtcpmsg, "dupack %lud ack %lud sndwnd %d advwin %d\n",
@@ -1766,6 +1768,8 @@ tcpoutput(Conv *s)
 			if(ssize < n)
 				n = ssize;
 			tcb->resent += n;
+			netlog(f, Logtcp, "rexmit: %I.%d -> %I.%d ptr %lux nxt %lux\n",
+				s->raddr, s->rport, s->laddr, s->lport, tcb->snd.ptr, tcb->snd.nxt);
 			tpriv->stats[RetransSegs]++;
 		}