From 812b0290f086fad80c7f7b93bb311cb5f9bfb561 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Sat, 30 Mar 1991 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1991-03-30

---
 port/deviproute.c | 207 ++++++++++++++++++++++++++++++++++++++++++++++
 port/stnoether.c  |  15 ++++
 2 files changed, 222 insertions(+)
 create mode 100644 port/deviproute.c

diff --git a/port/deviproute.c b/port/deviproute.c
new file mode 100644
index 0000000000000000000000000000000000000000..3213bf861dcf016c874b1da7bc1fb100b4da0cee
--- /dev/null
+++ b/port/deviproute.c
@@ -0,0 +1,207 @@
+#include <u.h>
+#include <libc.h>
+
+typedef	struct Iproute	Iproute;
+typedef	struct Iprtab	Iprtab;
+
+enum
+{
+	Nroutes=	256,
+};
+
+/*
+ *  Standard ip masks for the 3 classes
+ */
+uchar classmask[4][4] = {
+	0xff,	0,	0,	0,
+	0xff,	0,	0,	0,
+	0xff,	0xff,	0,	0,
+	0xff,	0xff,	0xff,	0,
+};
+#define CLASSMASK(x)	classmask[(*x>>6) & 3]
+
+/*
+ *  routes
+ */
+struct Iproute {
+	uchar	dst[4];
+	uchar	gate[4];
+	uchar	mask[4];
+	Iproute	*next;
+	int	inuse;
+};
+struct Iprtab {
+/*	Lock; */
+	Iproute *first;
+	Iproute	r[Nroutes];	/* routings */
+};
+Iprtab	iprtab;
+
+#define lock(x)
+#define unlock(x)
+
+void
+printroute(void)
+{
+	Iproute *r;
+
+	print("\n");
+	for(r = iprtab.first; r; r = r->next)
+		print("%d.%d.%d.%d  %d.%d.%d.%d  %d.%d.%d.%d\n",
+			r->dst[0], r->dst[1], r->dst[2], r->dst[3],
+			r->mask[0], r->mask[1], r->mask[2], r->mask[3],
+			r->gate[0], r->gate[1], r->gate[2], r->gate[3]);
+	print("\n");
+}
+
+/*
+ *  The chosen route is the one obeys the constraint
+ *		r->mask[x] & dst[x] == r->dst[x] for x in 0 1 2 3
+ *
+ *  If there are several matches, the one whose mask has the most
+ *  leading ones (and hence is the most specific) wins.
+ *
+ *  If there is no match, the default gateway is chosen.
+ */
+void
+iproute(uchar *dst, uchar *gate)
+{
+	Iproute *r;
+
+	/*
+	 *  first check routes
+	 */
+	lock(&iprtab);
+	for(r = iprtab.first; r; r = r->next){
+		if((r->mask[0]&dst[0]) == r->dst[0]
+		&& (r->mask[1]&dst[1]) == r->dst[1]
+		&& (r->mask[2]&dst[2]) == r->dst[2]
+		&& (r->mask[3]&dst[3]) == r->dst[3]){
+			memmove(gate, r->gate, 4);
+			unlock(&iprtab);
+			return;
+		}
+	}
+	unlock(&iprtab);
+
+	/*
+	 *  else just return what we got
+	 */	
+	memmove(gate, dst, 4);
+}
+
+/*
+ *  Compares 2 subnet masks and returns an integer less than, equal to,
+ *  or greater than 0, according as m1 is numericly less than,
+ *  equal to, or greater than m2.
+ */
+ipmaskcmp(uchar *m1, uchar *m2)
+{
+	int a, i;
+
+	for(i = 0; i < 4; i++){
+		if(a = *m1++ - *m2++)
+			return a;
+	}
+	return 0;
+}
+
+/*
+ *  Add a route, create a mask if the first mask is 0.
+ *
+ *  All routes are stored sorted by the length of leading
+ *  ones in the mask.
+ *
+ *  NOTE: A default route has an all zeroes mask and dst.
+ */
+void
+ipaddroute(uchar *dst, uchar *mask, uchar *gate)
+{
+	Iproute *r, *e, *free;
+	int i;
+
+	if(mask==0)
+		mask = CLASSMASK(dst);
+
+	/*
+	 *  filter out impossible requests
+	 */
+	for(i = 0; i < 4; i++)
+		if((dst[i]&mask[i]) != dst[i])
+			return;
+
+	/*
+	 *  see if we already have a route for
+	 *  the destination
+	 */
+	lock(&iprtab);
+	free = 0;
+	for(r = iprtab.r; r < &iprtab.r[Nroutes]; r++){
+		if(r->inuse == 0){
+			free = r;
+			continue;
+		}
+		if(memcmp(dst, r->dst, 4)==0 && memcmp(mask, r->mask, 4)==0){
+			memmove(r->gate, gate, 4);
+			unlock(&iprtab);
+			return;
+		}
+	}
+
+	/*
+	 *  add the new route in sorted order
+	 */
+	memmove(free->dst, dst, 4);
+	memmove(free->mask, mask, 4);
+	memmove(free->gate, gate, 4);
+	free->inuse = 1;
+	for(r = iprtab.first; r; r = r->next){
+		if(ipmaskcmp(free->mask, r->mask) > 0)
+			break;
+		e = r;
+	}
+	free->next = r;
+	if(r == iprtab.first)
+		iprtab.first = free;
+	else
+		e->next = free;
+	unlock(&iprtab);
+}
+
+/*
+ *  remove a route
+ */
+void
+ipremroute(uchar *dst, uchar *mask)
+{
+	Iproute *r, *e;
+
+	lock(&iprtab);
+	for(r = iprtab.first; r; r = r->next){
+		if(memcmp(dst, r->dst, 4)==0 && memcmp(mask, r->mask, 4)==0){
+			if(r == iprtab.first)
+				iprtab.first = r->next;
+			else
+				e->next = r->next;
+			r->inuse = 0;
+			break;
+		}
+		e = r;
+	}
+	unlock(&iprtab);
+}
+
+/*
+ *  remove all routes
+ */
+void
+ipflushroute(void)
+{
+	Iproute *r;
+
+	lock(&iprtab);
+	for(r = iprtab.first; r; r = r->next)
+		r->inuse = 0;
+	iprtab.first = 0;
+	unlock(&iprtab);
+}
diff --git a/port/stnoether.c b/port/stnoether.c
index acbbe52c9560e57b792fd610eedfbec0d448dd43..bf210a10c39103985154829a2fd2df1f8e514e7c 100644
--- a/port/stnoether.c
+++ b/port/stnoether.c
@@ -267,10 +267,25 @@ noetheriput(Queue *q, Block *bp)
 static void
 etherparse(uchar *to, char *from)
 {
+	ulong ip;
+	uchar nip[4];
 	int tdig;
 	int fdig;
 	int i;
 
+#ifdef MAGNUM
+	/* Dot means ip address */
+	if(strchr(from, '.')) {
+		ip = ipparse(from);
+		if(ip == 0)
+			error(Ebadnet);
+
+		hnputl(nip, ip);			
+		if(arp_lookup(nip, to))
+			return;
+	}
+#endif
+
 	if(strlen(from) != 12)
 		error(Ebadnet);