#!/bin/bash

# from https://github.com/j3k0/quicktinc

set -e

IMAGE="fschl/tinc"

function usage() {
    echo "
Usage:
    $0 [OPTIONS]

Options:
    --net=NET_NAME           Network name (required)
    --node=NODE_NAME         Node name (required)
    --public-ip=PUBLIC_IP    Node's public IP (required)
    --private-ip=PRIVATE_IP  Node's private IP (required)
    --connect-to=HOST        Name of another node (optional, repeatable)
    --interface=tun0         Network interface to create (optional, default=tun0)
    --config=/srv/tinc       Where to save tinc networks (optional, default=$(pwd)/etc-tinc)
    --up                     Also start the daemon

Example:
    $0 --net=demonet --node=node23 --public-ip=8.9.10.11 --private-ip=10.0.0.23 --connect-to=node1 --connect-to=node2 --up

Report bugs to <https://github.com/j3k0/quicktinc>
"
    exit 1
}

for i in "$@"
do
    case $i in
        -n=*|--net=*)
            NET_NAME="${i#*=}"
            shift # past argument=value
            ;;
        -o=*|--node=*)
            NODE_NAME="${i#*=}"
            shift # past argument=value
            ;;
        -v=*|--private-ip=*)
            PRIVATE_IP="${i#*=}"
            shift # past argument=value
            ;;
        -p=*|--public-ip=*)
            PUBLIC_IP="${i#*=}"
            shift # past argument=value
            ;;
        -c=*|--connect-to=*)
            CONNECT_TO="$CONNECT_TO ${i#*=}"
            shift # past argument=value
            ;;
        -i=*|--interface=*)
            INTERFACE="${i#*=}"
            shift # past argument=value
            ;;
        -C=*|--config=*)
            TINC_HOME="${i#*=}"
            shift # past argument=value
            ;;
        --up)
            TINC_UP=YES
            ;;
        *)
            # unknown option
            usage
            ;;
    esac
done

if [ "_$NET_NAME" = "_" ]; then usage; fi
if [ "_$NODE_NAME" = "_" ]; then usage; fi
if [ "_$PRIVATE_IP" = "_" ]; then usage; fi
if [ "_$PUBLIC_IP" = "_" ]; then usage; fi

if [ "_$INTERFACE" = "_" ]; then
    INTERFACE=tun0
fi

if [ "_$TINC_HOME" = "_" ]; then
    TINC_HOME=$(pwd)/etc-tinc
fi

function tinc() {
    docker run --rm --net=host --device=/dev/net/tun --cap-add NET_ADMIN --volume $TINC_HOME:/etc/tinc $IMAGE -n $NET_NAME "$@"
}

# Initialize configuration file
tinc init $NODE_NAME

# Setup host file
# Declare public and private IPs in the host file, CONFIG/NET/hosts/HOST
echo "Address = $PUBLIC_IP" >> $TINC_HOME/$NET_NAME/hosts/$NODE_NAME
echo "Subnet = $PRIVATE_IP/32" >> $TINC_HOME/$NET_NAME/hosts/$NODE_NAME

# Tweak the config to add our particular setup
tinc add AddressFamily ipv4
tinc add Device /dev/net/tun
tinc add Interface $INTERFACE
if [ "_$CONNECT_TO" != "_" ]; then
    for i in $CONNECT_TO; do
        tinc add ConnectTo $i
    done
fi

# Edit the tinc-up script
cat << EOF > $TINC_HOME/$NET_NAME/tinc-up
#!/bin/sh
ifconfig \$INTERFACE $PRIVATE_IP netmask 255.255.255.0
EOF

cat << EOF > $TINC_HOME/$NET_NAME/tinc-down
#!/bin/sh
ifconfig \$INTERFACE down
EOF

chmod +x $TINC_HOME/$NET_NAME/tinc-up
chmod +x $TINC_HOME/$NET_NAME/tinc-down

if [ "_$TINC_UP" != "_" ]; then
    NAME=tinc_$NET_NAME_$NODE_NAME
    docker run -d --restart=always --name=$NAME --net=host --device=/dev/net/tun --cap-add NET_ADMIN --volume $TINC_HOME:/etc/tinc $IMAGE -n $NET_NAME start -D
    echo "Docker container started with name: $NAME"
fi