--- /etc/init.d/minissdpd.old	2014-12-28 19:59:04.344867561 -0600
+++ /etc/init.d/minissdpd	2014-12-28 23:11:53.714998895 -0600
@@ -3,30 +3,34 @@
 MINISSDPD="/usr/sbin/minissdpd"
 PIDFILE="/var/run/minissdpd.pid"

-ROUTE="/bin/route"
-IFCONFIG="/bin/ifconfig"
-
 depend() {
 	need net
 	before miniupnpd
 }

+interfaceup() {
+	# interface exists?
+	if [ ! -f /sys/class/net/$1/flags ]; then return 1; fi
+	let "IFUP = `cat /sys/class/net/$1/flags` & 1"
+	# interface has UP flag?
+	if [ $IFUP -eq 0 ]; then return 1; fi
+	return 0
+}
+
+# awk script: scans the /proc routing table for local subnets
+# 1. filter list for entries with a gateway (column 3) of 0.0.0.0 (ie interface-local)
+# 2. read column 2 for network-order hex encoded subnet address
+# 3. match against a 10.x.x.x, 172.(16-31).x.x, or 192.168.x.x address
+# 4. print out any interface (column 1) that matches
+privateinterfaces() {
+	awk -f - /proc/net/route <<'FindPrivateNetworks'
+function p(m,n) { return(and(IP,m) == n); }
+$3=="00000000" { IP=strtonum("0x"$2); if (p(0xff,0x0a) || p(0x1fff,0x10ac) || p(0xffff,0xa8c0)) print $1; }
+FindPrivateNetworks
+}
+
 checkconfig() {
-	if [ "x$MINISSDPD_IFACE" != "x" ]; then
-		interfaces=$($IFCONFIG | grep "Link encap" | awk '{ print $1 }')
-		for interface in $MINISSDPD_IFACE; do
-			hit=0
-			for available in $interfaces; do
-				if [ "$interface" = "$available" ]; then
-					hit=1
-				fi
-			done
-			if [ $hit = 0 ]; then
-				ewarn "Interface $interface not available"
-				return 1
-			fi
-		done
-	fi
+	# no-op
 	return 0
 }

@@ -34,22 +38,24 @@
 	ebegin "Starting minissdpd"
 	checkconfig || return 1

+	ARGS=""
 	if [ "x$MINISSDPD_IFACE" = "x" ]; then
-		# We assume that the default interface has an IP address
-		interface=$($ROUTE | grep default | awk -- '{ print $8 }')
-		IP="$($IFCONFIG $interface | grep 'inet' | sed 's/^.*inet \([0-9.]\+\).\+/\1/')"
-		ARGS="-i $IP "
+		ewarn "No interfaces provided, using interfaces on private networks"
+		IFLIST=$(privateinterfaces)
 	else
-		ARGS=""
-		for interface in $MINISSDPD_IFACE; do
-			# An interface may not have an IP address, so don't listen if it doesn't
-			IP="$($IFCONFIG $interface | grep 'inet' | sed 's/^.*inet \([0-9.]\+\).\+/\1/')"
-			if [ "x$IP" != "x" ]; then
-				ARGS+="-i $IP "
-			fi
-		done
+		IFLIST="$MINISSDPD_IFACE"
 	fi

+	eindent
+	for IF in $IFLIST; do
+		if interfaceup $IF; then
+			einfo Adding interface $IF
+			ARGS+="-i $IF "
+		else
+			ewarn "Interface $IF is not up"
+		fi
+	done
+	eoutdent
 	start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $MINISSDPD -- $ARGS
 	eend $?
 }