ipcheck
A statically linked binary which, given a string decides if it is
- malformed: not an IPv4 address
- public: a routable IPv4 address
- private: a non-routable IPv4 per rfc1918
- loopback: rfc1700
- linklocal: rfc3927
- 6to4: rfc3068
- documentation: rfc5737
See wikipedia for all the gory details.
Usage
In your dockerfile, add something like this:
FROM alpine
ENV IPCHECK_VERSION="0.1"
RUN apk --no-cache add curl \
&& curl -o /usr/local/sbin/ipcheck https://github.com/ahammond/ipcheck/releases/download/v$IPCHECK_VERSION/ipcheck
CMD [ "entrypoint.sh" ]And then in your entrypoint.sh or wherever you're doing validation:
IP_TYPE=$(ipcheck "$MY_IP")
if [ "public" != "$IP_TYPE" ]; then
echo "I need a public IP, but $MY_IP is $IP_TYPE"
exit 1
fi