Add mailer and wireguard helper

mailer

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+if [ $# -ne 4 ]; then
+    echo "$0 subject from bcc-addr addressfile"
+    echo "f.i. $0 'How are you?' 'Some Body <from@example.com>' 'another@example.com' ./addresses "
+    echo "Address file format: | Name | Mail |"
+    exit 1
+fi
+
+subject=$1; shift
+from=$1; shift
+bcc=$1; shift
+addresses_file=$1; shift
+
+
+while read line; do
+    name=$(echo $line | awk -F '|' '{ print $2 }' | sed -e 's/^ *//' -e 's/ *$//')
+    email=$(echo $line | awk -F '|' '{ print $3 }' | sed -e 's/^ *//' -e 's/ *$//')
+
+    sed "s/PERSON/$name/" mail | \
+        mail -s "$subject" \
+             -r "$from" \
+             -b "$bcc" \
+             "$name <$email>"
+done < "$addresses_file"

wireguard-fix-endpoint.sh

@@ -0,0 +1,51 @@
+#!/bin/sh
+# 2020-01-19
+# Nico Schottelius
+# Periodically fix the wireguard endpoint
+
+endpoint=vpn-2a0ae5c1.ungleich.ch
+tunnel=wgungleich
+config=/etc/wireguard/${tunnel}.conf
+
+endpoint=$(grep -i ^endpoint ${config}  | cut -d= -f2)
+host=$(echo $endpoint| cut -d: -f1)
+port=$(echo $endpoint| cut -d: -f2)
+publickey=$(grep -i ^publickey ${config}  | cut -d= -f2)
+
+# If wireguard is up, but with the wrong endpoint
+# (v4 address in an v6 only network or
+# v6 address in an v4 only network) the routing of
+# wireguard can break connectivity (i.e. AllowedIPs = ::/0
+# breaks IPv6 connectivity)
+
+# Thus we first need to shutdown the wireguard VPN to confirm
+# it's not wireguard preventing us to access the endpoint itself.
+# It would certainly be better to not needing to shut it down,
+# however I don't see a reliable way without skipping the wireguard
+# set `ip rule`
+
+wg-quick down ${tunnel}
+
+# Now do the DNS lookups, which should work without a tunnel up
+# (they also might have been prevented by wireguard up in the incorrect
+# address family)
+v6_addr=$(dig +short $endpoint aaaa)
+v4_addr=$(dig +short $endpoint a)
+
+v6_ok=""
+v4_ok=""
+
+ping -c3 $v6_addr >/dev/null && v6_ok=yes
+ping -c3 $v4_addr >/dev/null && v4_ok=yes
+
+# Now verify/check what is reachable
+if [ $v6_ok ]; then
+    wg-quick up ${tunnel}
+    wg set wgungleich peer ${publickey} endpoint ${v6_addr}:${port}
+elif [ $v4_ok ]; then
+    wg-quick up ${tunnel}
+    wg set wgungleich peer ${publickey} endpoint ${v4!_addr}:${port}
+else
+    echo "The endpoint ${endpoint} is unreachable, try again later" >&2
+    exit 1
+fi