Initial commit

Dockerfile

+FROM debian
+
+RUN apt update && apt install -y \
+    dnsutils \
+  && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /usr/src/app
+COPY ddns-route.sh .
+
+CMD ["/usr/src/app/ddns-route.sh"]

ddns-route.sh

+#!/bin/bash
+#DOMAIN=$1
+#PROTO=$2
+#TAIL=$3
+
+while :
+do
+
+EXISTING_ROUTE=$(ip route | grep "proto $PROTO")
+EXISTING=$(ip route | grep "proto $PROTO" | awk '{print $1}')
+CURRENT=$(dig $DOMAIN +short)
+if [ $? != 0 ]; then
+    echo "DNS error"
+    exit 1
+fi
+echo $EXISTING $CURRENT
+if [ "$EXISTING" == "$CURRENT" ]; then
+    echo "Same"
+else
+    echo "Diff"
+    DEL_CMD="ip route del $EXISTING_ROUTE"
+    ADD_CMD="ip route add $CURRENT proto $PROTO $TAIL"
+    echo $DEL_CMD
+    echo $ADD_CMD
+    bash -c "$DEL_CMD"
+    bash -c "$ADD_CMD"
+fi
+
+sleep 60
+done