#!/usr/bin/env bash

if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root."
   exit 1
fi

# We are here
dir=$(dirname $(realpath $0))

# Wrap into a tmux shell if it not already the case
tmux rename-session babel 2> /dev/null
res=$?
if ! [[ "$res" == 0 ]]; then
	exec tmux new-session $0
	exit 0
fi

tmux rename-window host

function reset() {
  echo "Reset previous configuration..."
  pkill -e vde_plug
  pkill -e babeld
  rm -rv /tmp/switch* /tmp/ns*
  ip route delete 172.17.0.0/16
  ip -6 route delete 2a0c:700:3012:3::1:0/112
  ip -6 route delete 2a0c:700:3012:3::2:0/112
  nft flush ruleset
}

reset

echo "Setup switches..."
vde_plug --daemon switch:///tmp/ext null://
vde_plug --daemon switch:///tmp/switch1 null://
vde_plug --daemon switch:///tmp/switch2 null://

# Connect to the exterior
sudo vde_plug --daemon vde:///tmp/ext tap://vde0
sudo ip link set dev vde0 up
sudo ip address add 10.2.1.1/30 dev vde0
sudo ip address add 2a0c:700:3012:3::ff:0/127 dev vde0

# Setup NAT
nft -f $dir/firewall/nat.conf

for i in 1 2 3 4; do
  echo "Creating new namespace..."
  mkdir -p /tmp/ns$i/log
  tmux new-window -n ns$i "unshare --user --map-root-user --net --mount"
  tmux select-window -t host

  sleep 1

  echo "Configure ns$i..."

  tmux send-keys -t ns$i "echo \$\$ > /tmp/ns$i/pid" Enter
  if [[ $i -eq 1 ]]; then
    tmux send-keys -t ns$i "vde_plug --daemon vde:///tmp/ext tap://vde0" Enter
    sleep 0.3
    tmux send-keys -t ns$i "ip link set vde0 up" Enter
    tmux send-keys -t ns$i "ip address add 10.2.1.2/30 dev vde0" Enter
    tmux send-keys -t ns$i "ip address add 2a0c:700:3012:3::ff:1/127 dev vde0" Enter
    tmux send-keys -t ns$i "ip route add 0.0.0.0/1 via 10.2.1.1 dev vde0 proto kernel" Enter
    tmux send-keys -t ns$i "ip route add 128.0.0.0/1 via 10.2.1.1 dev vde0 proto kernel" Enter
    tmux send-keys -t ns$i "ip -6 route add 2000::/4 via 2a0c:700:3012:3::ff:0 dev vde0 proto kernel" Enter
    tmux send-keys -t ns$i "echo \"interface vde0 type wired\" >> /tmp/ns$i/babeld.conf" Enter
    tmux send-keys -t ns$i "echo \"redistribute metric 256\" >> /tmp/ns$i/babeld.conf" Enter
  fi

  tmux send-keys -t ns$i "mount --bind /tmp/ns$i/log /var/log" Enter
done

echo "Enable links..."

# Switch 1: NS 1, 2, 3
for i in 1 2 3; do
  tmux send-keys -t ns$i "vde_plug --daemon vde:///tmp/switch1 tap://vde1" Enter
  sleep 0.3
  tmux send-keys -t ns$i "ip link set vde1 up" Enter
  tmux send-keys -t ns$i "ip address add 172.17.1.$i/32 dev vde1" Enter
  tmux send-keys -t ns$i "ip address add 2a0c:700:3012:3::1:$i/128 dev vde1" Enter
  tmux send-keys -t ns$i "echo \"interface vde1 type wired\" >> /tmp/ns$i/babeld.conf" Enter
done

# Switch 2: NS 2, 3, 4
for i in 2 3 4; do
  tmux send-keys -t ns$i "vde_plug --daemon vde:///tmp/switch2 tap://vde2" Enter
  sleep 0.3
  tmux send-keys -t ns$i "ip link set vde2 up" Enter
  tmux send-keys -t ns$i "ip address add 172.17.2.$i/32 dev vde2" Enter
  tmux send-keys -t ns$i "ip address add 2a0c:700:3012:3::2:$i/128 dev vde2" Enter
  tmux send-keys -t ns$i "echo \"interface vde2 type wired\" >> /tmp/ns$i/babeld.conf" Enter
done

ip route add 172.17.0.0/16 via 10.2.1.2
ip -6 route add 2a0c:700:3012:3::1:0/112 via 2a0c:700:3012:3::ff:1
ip -6 route add 2a0c:700:3012:3::2:0/112 via 2a0c:700:3012:3::ff:1

for i in 1 2 3 4; do
  tmux send-keys -t ns$i "touch /etc/babeld.conf && mount --bind /tmp/ns$i/babeld.conf /etc/babeld.conf" Enter
  tmux send-keys -t ns$i "babeld -D -I /tmp/ns$i/babeld.pid -G /tmp/ns$i/socket -S /tmp/ns1/state" Enter
done

for i in 2 3; do
  tmux send-keys -t ns$i "nft -f $dir/firewall/restrict-http.conf" Enter
done

bash

reset

tmux kill-session