File arp2ethers.patch of Package arpwatch

Index: arpwatch-3.1/arp2ethers
===================================================================
--- arpwatch-3.1.orig/arp2ethers
+++ arpwatch-3.1/arp2ethers
@@ -13,11 +13,50 @@
 #	- sort
 #
 
-sort +2rn arp.dat |
+sort -k 2 -rn arp.dat | \
     awk 'NF == 4 { print }' |
-    awk -f p.awk |
-    egrep -v '\.[0-9][0-9]*$' |
-    sed -e 's/	.*	/	/' |
-    awk -f d.awk |
-    awk -f e.awk |
-    sort
+    awk '
+{
+	e = $1
+	if (seen[e])
+		next
+	seen[e] = 1
+	print
+}' | egrep -v '\.[0-9][0-9]*$' | \
+     sed -e 's/	.*	/	/' | \
+    awk '
+BEGIN {
+	n = 0
+	sdecnet = "aa:0:4:"
+	ldecnet = length(sdecnet)
+}
+
+{
+	++n
+	e[n] = $1
+	h[n] = $2
+	if (sdecnet == substr($1, 1, ldecnet))
+		decnet[$2] = 1
+}
+
+END {
+	for (i = 1; i <= n; ++i) {
+		if (decnet[h[i]] && sdecnet != substr(e[i], 1, ldecnet))
+			h[i] = h[i] "-ip"
+		print e[i] "\t" h[i]
+	}
+}' | awk '
+{
+	if (!seen[$2]) {
+		seen[$2] = 1
+		print
+		next
+	}
+	h = $2 "-old"
+	s = h
+	for (n = 1; seen[h]; ++n)
+		h = s n
+	seen[h] = 1
+	print $1 "\t" h
+	next
+}' | sort