avoiding duplicate IPs in tinc scripts

[Lars Kruse]

Hello Hamish,


Am Wed, 1 Aug 2018 11:42:58 +1000
schrieb Hamish Moffatt <hamish at moffatt.email>:

> Currently I have the local tinc node's VPN IP in both the tinc-up script as
> well as in its hosts/$NODE file Subnet setting. Can this be avoided, to
> simplify deployment?

I use the following tinc-up script.
It determines the local node's host filename and parses all "Subnet" lines
without a slash (indicating networks) lines from it.


#!/bin/sh

set -eu

MY_HOST_FILE="/etc/tinc/$NETNAME/hosts/$NAME"

grep -i "^Subnet[^/]*$" "$MY_HOST_FILE" | cut -f 2 -d = | tr -d " " \
        | while read -r my_ip; do
    ip address add "${my_ip}/24" dev "$INTERFACE"
done

ip link set "$INTERFACE" up


The following details are imperfect:
* Subnet lines with a single-host prefix length ("/32") are ignored, too
* the network prefix length is part of the script
  (there is no way to determine it)

Maybe this helps ...

Cheers,
Lars