Added generic Njalla DDNS script

misc/generic-njalla-ddns.sh

@@ -0,0 +1,37 @@
+#!/bin/sh
+
+IP_TEMPFILE=/tmp/wanip
+NJALLA_SUBDOMAIN="thing.com"
+NJALLA_KEY="1234"
+
+# Gets the current WAN interface and IP(s)
+NET_ADDR=$(ip route get 9.9.9.9 | grep src | sed 's/.*src \(.* \)/\1/g' | cut -f1 -d ' ')
+NET_ADDR6=$(ip route get 2620:fe::fe | grep src | sed 's/.*src \(.* \)/\1/g' | cut -f1 -d ' ')
+
+if [ "$1" = "--query" ] || [ ! -f ${IP_TEMPFILE} ]; then
+    echo "Querying IP from DNS server"
+    NET_ADDR_OLD="$(nslookup -type=a ${NJALLA_SUBDOMAIN} | awk '/^Address: / { print $2 }')"
+    NET_ADDR6_OLD="$(nslookup -type=aaaa ${NJALLA_SUBDOMAIN} | awk '/^Address: / { print $2 }')"
+
+    if [ ! -f ${IP_TEMPFILE} ]; then
+        touch ${IP_TEMPFILE} || exit 1
+        echo "NET_ADDR_OLD=${NET_ADDR_OLD}" > $IP_TEMPFILE
+        echo "NET_ADDR6_OLD=${NET_ADDR6_OLD}" >> $IP_TEMPFILE
+    fi
+else
+    . ${IP_TEMPFILE}
+fi
+
+if [ "$NET_ADDR" != "$NET_ADDR_OLD" ] || [ "$NET_ADDR6" != "$NET_ADDR6_OLD" ] || [ "$1" = "--force" ]; then
+    echo "IPv4: ${NET_ADDR_OLD} => ${NET_ADDR}"
+    echo "IPv6: ${NET_ADDR6_OLD} => ${NET_ADDR6}"
+
+    wget -q -O /dev/null "https://njal.la/update/?h=${NJALLA_SUBDOMAIN}&k=${NJALLA_KEY}&a=${NET_ADDR}&aaaa=${NET_ADDR6}"
+    STATUS=$?
+    if [ $STATUS -ne 0 ]; then
+        echo "Could not set DDNS IP! (${STATUS})"
+    fi
+
+    echo "NET_ADDR_OLD=${NET_ADDR}" > $IP_TEMPFILE
+    echo "NET_ADDR6_OLD=${NET_ADDR6}" >> $IP_TEMPFILE
+fi