Setup script for rpi2/3 router with ubuntu core

rpi-setup.sh

#!/bin/bash

# first do a reboot, to let some of the snaps refresh
# (in particular the wifi wont work as an AP until a new core + kernel snap is installed)
# this will happen by itself via a timer, but if not, just give it a kick.
# sudo reboot

# setup our hostname
sudo hostnamectl set-hostname fbi

# disable password auth, so only our ssh key can login
echo 'PasswordAuthentication no' | sudo tee -a /etc/ssh/sshd_config

# install our firewall
snap install ufw

# allow ssh from everywhere, because we want to use our rpi, don't we?
sudo ufw allow ssh/tcp

# lets deny most things...
sudo ufw default deny incoming
sudo ufw deny in on eth0
sudo ufw route deny in on eth0

# and enable the firewall for now
echo 'y' | sudo ufw enable
# allow through routing
sudo ufw route allow in on wlan0 out on eth0 from 192.168.42.0/24

# allow dns
sudo ufw allow out on wlan0 from 192.168.42.1 to 192.168.42.0/24 port domain proto udp
sudo ufw allow in on wlan0 from 192.168.42.0/24 to 192.168.42.1 port domain proto udp 

# allow dhcp
sudo ufw allow in on wlan0 from any port bootpc proto udp
sudo ufw allow out on wlan0 to any port bootps proto udp
sudo ufw reload

# install our wireless ap and set it up following the on-screen guide
snap install wifi-ap
sudo wifi-ap.setup-wizard

# lets get some fun containers
snap install lxd

# first workaround (seems like the lxd daemon does not come up quickly enough by default)
sleep 60

sudo lxd init
sudo lxc launch images:ubuntu/zesty openvpn
sudo lxc launch images:ubuntu/zesty quassel

# lets set their internal ips to be static
sudo lxc network attach lxdbr0 openvpn eth0
sudo lxc network attach lxdbr0 quassel eth0


OPENVPN_IP=$(sudo lxc list -c 4,n | grep openvpn | cut -d' ' -f2)

sudo lxc config device set openvpn eth0 ipv4.address $OPENVPN_IP
sudo lxc config device set quassel eth0 ipv4.address $(sudo lxc list -c 4,n | grep quassel | cut -d' ' -f2)

# and have them start on boot
sudo lxc config set openvpn boot.autostart true
sudo lxc config set quassel boot.autostart true

sudo lxc exec quassel -- apt install -y quassel-core

sudo lxc exec openvpn -- apt install -y iptables
sudo lxc exec openvpn -- iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -j SNAT --to $OPENVPN_IP
sudo lxc exec openvpn -- bash -c "iptables-save > /etc/iptables.rules"
sudo lxc exec openvpn -- bash -c 'echo -e "#!/bin/sh\niptables-restore < /etc/iptables.rules\nexit 0" > /etc/network/if-pre-up.d/iptables'
sudo lxc exec openvpn -- chmod +x /etc/network/if-pre-up.d/iptables

# install openvpn via the great script from Angristan
sudo lxc exec openvpn -- apt install -y wget
sudo lxc exec openvpn -- wget https://raw.githubusercontent.com/Angristan/OpenVPN-install/master/openvpn-install.sh
sudo lxc exec openvpn -- chmod +x openvpn-install.sh
# when running this, generating diffie-hellman params can take much longer than a few hours...
sudo lxc exec openvpn -- ./openvpn-install.sh

# workaround #2, bug https://github.com/Nyr/openvpn-install/issues/206
sudo lxc exec openvpn -- sed -i '/LimitNPROC/d' /lib/systemd/system/openvpn@.service

# workaround #3, https://askubuntu.com/questions/650471/how-do-i-allow-dev-net-tun-in-a-lxd-managed-lxc-container
sudo lxc config set openvpn raw.lxc 'lxc.cgroup.devices.allow = c 10:200 rwm'
sudo lxc config device add openvpn tun unix-char path=/dev/net/tun

# workaround #4
sudo systemctl disable snap.lxd.daemon.service
sudo cp /etc/systemd/system/snap.lxd.daemon.service /etc/systemd/system/lxd.daemon.service
sudo sed -i '/X-Snappy/d' /etc/systemd/system/lxd.daemon.service
sudo sed -i '/WorkingDirectory/d' /etc/systemd/system/lxd.daemon.service
sudo sed -i '/ExecStop/d' /etc/systemd/system/lxd.daemon.service
sudo sed -i 's/ExecStart.*/ExecStart=\/snap\/bin\/lxd/' /etc/systemd/system/lxd.daemon.service
sudo systemctl daemon-reload
sudo systemctl enable lxd.daemon.service
sudo systemctl start lxd.daemon.service

# get the openvpn client config file
sudo lxc file pull openvpn/root/client.ovpn - > client.ovpn

# and now allow port forwarding for openvpn https://www.cyberciti.biz/faq/how-to-configure-ufw-to-forward-port-80443-to-internal-server-hosted-on-lan/
echo -e "\n*nat\n:PREROUTING ACCEPT [0:0]\n-A PREROUTING -i eth0 -p udp --dport 1194 -j  DNAT --to-destination $OPENVPN_IP\nCOMMIT" | sudo tee -a /var/snap/ufw/current/etc/ufw/before.rules
sudo ufw route allow in on eth0 from any out on lxdbr0 to $OPENVPN_IP port openvpn proto udp
sudo ufw reload

# for some phone/laptop sharing goodness
snap install syncthing

# to give us a free dynamic dns name
snap install noip-client
sudo noip-client.configure
sudo systemctl restart snap.noip-client.launcher.service