#!/bin/bash
# Create L3 switch based on Tun Ubuntu Server 18.04 using FRrouting and Openswitch

frr_ver='6.0'
frr_file='frr_6.0-1.ubuntu18.04+1_amd64.deb'
user='ubuntu'
ttyS0_service='/lib/systemd/system/ttyS0.service'


# Check if I am root
 [ "$(id -u)" != 0 ] && echo "Run the script as root, exiting" && exit 1 

# Update packages
 apt-get update
 [ "$?" != 0 ] && echo "System can't be updated, exiting" && exit 1

# Check if we utilities are installed -  ifupdown to manage interfaces instead netplan
 for package in ifupdown openvswitch-switch; do
  dpkg --list | grep "$package" &>/dev/null
  [ "$?" == 1 ] && sudo apt-get -y install "$package"
 done

# Check if ipv4_forwarding is enabled"
 fwd="$(sysctl net.ipv4.ip_forward | cut -d ' ' -f3)"
 if [ "$fwd" == 0 ]; then
    sysctl -w net.ipv4.ip_forward=1
    sysctl -p /etc/sysctl.conf
    echo "I have enabled IPv4 forwarding"
 elif [ "$fwd" == 1 ]; then 
    echo "IPv4 forwarding is enabled betwwen interfaces, nothing to do"
 else
    echo "IPv4 forwarding between interfaces is not enabled, exiting"
    exit 1
 fi    

# Stop renaming interface e.g. eth0 to ens3
 sed -i 's/GRUB_CMDLINE_LINUX=""/GRUB_CMDLINE_LINUX="net.ifnames=0 biosdevname=0"/g' /etc/default/grub
 grub-mkconfig -o /boot/grub/grub.cfg

# Redirect video output to serial console
 echo '[Unit]' > "$ttyS0_service"
 echo -e "Description=Serial Console Service\n" >> "$ttyS0_service"
 echo '[Service]' >> "$ttyS0_service"
 echo 'ExecStart=/sbin/getty -L 115200 ttyS0 vt102' >> "$ttyS0_service"
 echo -e "Restart=always\n" >> "$ttyS0_service"
 echo '[Install]' >> "$ttyS0_service"
 echo 'WantedBy=multi-user.target' >> "$ttyS0_service"

 systemctl daemon-reload
 systemctl enable ttyS0
 systemctl start ttyS0
 
 
# FRRouting is not in repository we need to install it locally
 wget https://github.com/FRRouting/frr/releases/download/frr-"$frr_ver"/"$frr_file"
 apt-get -y install ./"$frr_file"
 if [ "$?" != 0 ]; then
    echo "FRrouting can't be installed, exiting" && exit 1
 else
    rm "$frr_file"
 fi

# Enable routing daemons, create empty config files, change owner & group to frr, set privilleges
 for daemon in zebra bgpd ospfd ospf6d ripd ripngd isisd eigrpd; do
    sed -i "s/$daemon=no/$daemon=yes/g" /etc/frr/daemons
    touch /etc/frr/"$daemon".conf
    chown frr:frr /etc/frr/"$daemon".conf
    chmod 640 /etc/frr/"$daemon".conf
 done

# Add user to groups frr & frrvty
 sudo usermod -a -G frr "$user"
 sudo usermod -a -G frrvty "$user"

# Restart the FRrouting service
 service frr restart
 if [ "$?" == 0 ]; then
    echo "FRRouting service restarted successfully"
 else
    echo "Can't restart FRRouting service" && exit 1
 fi

# Reduce timeout for network interfaces to 15sec during boot
 mkdir -p /etc/systemd/system/networking.service.d
 echo "[Service]" > /etc/systemd/system/networking.service.d/reduce-timeout.conf
 echo "TimeoutStartSec=15" >> /etc/systemd/system/networking.service.d/reduce-timeout.conf

exit 0