From 830f705b607b26a9f6d645d7ef2a314b604b13d1 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Sun, 13 Oct 1991 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1991-10-13

---
 port/devip.c |   5 +--
 port/ipdat.h |   1 +
 port/stil.c  | 115 +++++++++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 113 insertions(+), 8 deletions(-)

diff --git a/port/devip.c b/port/devip.c
index 8a9806ccf94107e0549253e4bb107d49082b1fbc..5494dc7cb51904e67613cf9dfc2669394f3533ca 100644
--- a/port/devip.c
+++ b/port/devip.c
@@ -9,7 +9,6 @@
 
 #include	"devtab.h"
 
-
 enum
 {
 	Nrprotocol	= 3,		/* Number of protocols supported by this driver */
@@ -605,7 +604,6 @@ void
 tcpstopen(Queue *q, Stream *s)
 {
 	Ipconv *ipc;
-	static int donekproc;
 
 	/* Start tcp service processes */
 	if(!Tcpoutput) {
@@ -719,7 +717,7 @@ tcpstclose(Queue *q)
 
 
 /* 
- * ptcl_csum - protcol cecksum routine
+ * ptcl_csum - protcol checksum routine
  */
 ushort
 ptcl_csum(Block *bp, int offset, int len)
@@ -858,4 +856,3 @@ ip_conn(Ipconv *ic, Port dst, Port src, Ipaddr dest, char proto)
 
 	return 0;
 }
-
diff --git a/port/ipdat.h b/port/ipdat.h
index 3a2ba84f28541407d6e2b0850221713564c94f74..eda2f70fa3f69b7812fe43f3a9360ade232f47da 100644
--- a/port/ipdat.h
+++ b/port/ipdat.h
@@ -108,6 +108,7 @@ enum
 	Ilack,
 	Ilquerey,
 	Ilstate,
+	Ilreset,
 };
 
 #define TCP_PKT	(TCP_EHSIZE+TCP_IPLEN+TCP_PHDRSIZE)
diff --git a/port/stil.c b/port/stil.c
index cf367999bd7dee3a8f8da7e72ec0bcf53fec7e27..32954962dc35d07a8dfcfa053eafb4d64d247e75 100644
--- a/port/stil.c
+++ b/port/stil.c
@@ -12,14 +12,26 @@
 #include 	"ipdat.h"
 
 #define DPRINT if(pip)print
+int ilcksum = 1;
+Queue	*Iloutput;		/* Il to lance output channel */
 
-void	ilrcvmsg(Ipconv *, Block *);
+void	ilrcvmsg(Ipconv*, Block*);
+void	ilackproc(void*);
 
 void
 ilopen(Queue *q, Stream *s)
 {
 	Ipconv *ipc;
 
+	/* Start il service processes */
+	if(!Iloutput) {
+		Iloutput = WR(q);
+		/* This never goes away - we use this queue to send acks/rejects */
+		s->opens++;
+		s->inuse++;
+		kproc("ilack", ilackproc, 0);
+	}
+
 	ipc = &ipconv[s->dev][s->id];
 	ipc->ipinterface = newipifc(IP_ILPROTO, ilrcvmsg, ipconv[s->dev],
 			            1500, 512, ETHER_HDR, "IL");
@@ -43,7 +55,9 @@ iloput(Queue *q, Block *bp)
 {
 	Ipconv *ipc;
 	Ilhdr *ih;
+	Ilcb *ic;
 	int dlen;
+	Block *np;
 
 	/* Prepend udp header to packet and pass on to ip layer */
 	ipc = (Ipconv *)(q->ptr);
@@ -71,22 +85,115 @@ iloput(Queue *q, Block *bp)
 	bp = padb(bp, IL_EHSIZE+IL_HDRSIZE);
 
 	ih = (Ilhdr *)(bp->rptr);
+	ic = &ipc->ilctl;
 
 	hnputs(ih->illen, dlen+IL_EHSIZE+IL_HDRSIZE);
 	hnputs(ih->ilsrc, ipc->psrc);
 	hnputs(ih->ildst, ipc->pdst);
 	ih->iltype = Ildata;
 	ih->ilspec = 0;
-	hnputl(ih->ilid, ipc->ilctl.sent++);
-	hnputl(ih->ilack, ipc->ilctl.recvd);
+	hnputl(ih->ilid, ic->sent++);
+	hnputl(ih->ilack, ic->recvd);
 	ih->ilsum[0] = 0;
 	ih->ilsum[1] = 0;
 
+	/* Checksum of ilheader plus data (not ip & no pseudo header) */
+	if(ilcksum)
+		hnputs(ih->ilsum, ptcl_csum(bp, IL_EHSIZE, dlen+IL_HDRSIZE));
+
+	/* Enqueue a copy on the unacked queue in case this one gets lost */
+	np = copyb(bp, blen(bp));
+	if(ic->unacked) {
+		ic->unackedtail->next = np;
+		ic->unackedtail = np;
+	}
+	else {
+		ic->unacked = np;
+		ic->unackedtail = np;
+	}
+	np->next = 0;
+
 	PUTNEXT(q, bp);
 }
 
-
 void
 iliput(Queue *q, Block *bp)
+{
+	PUTNEXT(q, bp);
+}
+
+void
+ilrcvmsg(Ipconv *ipc, Block *bp)
+{
+	Ilhdr *ih;
+
+	ih = (Ilhdr *)bp;
+
+	plen = blen(bp);
+	if(plen < IL_EHSIZE+IL_HDRSIZE)
+		goto drop;
+
+	if(ilcksum && ptcl_csum(bp, IL_EHSIZE, plen) != 0) {
+		print("il: cksum error\n");
+		goto drop;
+	}
+
+	s = ip_conn(ipc, hngets(ih->ildst), hngets(ih->ilsrc), hngetl(), IP_ILPROTO);
+	if(s == 0) {
+		ilsentctl(0, ih, Ilreset);
+		goto drop;
+	}
+
+	switch(s->state) {
+	case Closed:
+		ilsentctl(0, ih, Ilreset);
+		goto drop;
+	case Syncee:
+	case Syncer:
+	case Established:
+	case Closing:
+	}	
+	
+drop:
+	freeb(bp);
+}
+
+void
+ilsendctl(Ipconv *ipc, Ilhdr *inih, int type)
+{
+	Ilhdr *ih;
+	Ilcb *ic;
+	Block *bp;
+
+	bp = allocb(IL_EHSIZE+IL_HDRSIZE);
+	ih = (Ilhdr *)(bp->rptr);
+	ic = &ipc->ilctl;
+
+	hnputs(ih->illen, IL_EHSIZE+IL_HDRSIZE);
+	if(inih) {
+		hnputs(ih->ilsrc, inih->ildst);
+		hnputs(ih->ildst, inih->ilsrc);
+		hnputl(ih->ilid, inih->recvd);
+		hnputl(ih->ilack, inih->sent);
+	}
+	else {
+		hnputs(ih->ilsrc, ipc->psrc);
+		hnputs(ih->ildst, ipc->pdst);
+		hnputl(ih->ilid, ic->sent);
+		hnputl(ih->ilack, ic->recvd);
+	}
+	ih->iltype = type;
+	ih->ilspec = 0;
+	ih->ilsum[0] = 0;
+	ih->ilsum[1] = 0;
+
+	if(ilcksum)
+		hnputs(ih->ilsum, ptcl_csum(bp, IL_EHSIZE, IL_HDRSIZE));
+
+	PUTNEXT(Iloutput, bp);
+}
+
+void
+ilackproc(void *junk)
 {
 }