#!/bin/bash
#
# .---.                  .              .
# |                      |              |
# |--- .--. .-.  .-.  .-.|  .-. .--.--. |.-.  .-. .--.  .-.
# |    |   (.-' (.-' (   | (   )|  |  | |   )(   )|  | (.-'
# '    '     --'  --'  -' -  -' '  '   -' -'   -' '   -  --'
#
#                    Freedom in the Cloud
#
# Used to enable or disable batman mesh protocol on wlanX
#
# License
# =======
#
# Copyright (C) 2015-2016 Bob Mottram <bob@robotics.uk.to>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

PROJECT_NAME='freedombone'
COMPLETION_FILE=/root/${PROJECT_NAME}-completed.txt

if [[ $1 == "start" ]]; then
    # install avahi
    sed -i "s|#host-name=.*|host-name=$(hostname)|g" /etc/avahi/avahi-daemon.conf
    sed -i "s|host-name=.*|host-name=$(hostname)|g" /etc/avahi/avahi-daemon.conf
    sed -i "s|use-ipv4=.*|use-ipv4=yes|g" /etc/avahi/avahi-daemon.conf
    sed -i "s|use-ipv6=.*|use-ipv6=no|g" /etc/avahi/avahi-daemon.conf
    sed -i "s|#disallow-other-stacks=.*|disallow-other-stacks=yes|g" /etc/avahi/avahi-daemon.conf
    sed -i "s|hosts:.*|hosts:          files mdns4_minimal dns mdns4 mdns|g" /etc/nsswitch.conf
fi

# Mesh definition
WIFI_SSID=
if ! grep -q "WIFI_SSID:" $COMPLETION_FILE; then
    WIFI_SSID='mesh'
else
    WIFI_SSID=$(cat $COMPLETION_FILE | grep "WIFI_SSID:" | awk -F ':' '{print $2}')
fi
sed -i "s|WIFI_SSID:.*|WIFI_SSID:${WIFI_SSID}|g" $COMPLETION_FILE

CELLID='any'

CHANNEL=
if ! grep -q "Wifi channel:" $COMPLETION_FILE; then
    CHANNEL=2
else
    CHANNEL=$(cat $COMPLETION_FILE | grep "Wifi channel:" | awk -F ':' '{print $2}')
fi
sed -i "s|Wifi channel:.*|Wifi channel:${CHANNEL}|g" $COMPLETION_FILE

ZERONET_PORT=15441
IPFS_PORT=4001
SYNCTHING_PORT=22000

# Ethernet bridge definition (bridged to bat0)
BRIDGE=br-mesh
IFACE='wlan0'
EIFACE=eth0

if [[ $IFACE == "wlan0" ]]; then
    if grep -q "wlan1" /proc/net/dev; then
        IFACE=wlan1
    fi
fi
if [[ $IFACE == "wlan0" ]]; then
    if grep -q "wlan2" /proc/net/dev; then
        IFACE=wlan2
    fi
fi
if [[ $IFACE == "wlan0" ]]; then
    if grep -q "wlan3" /proc/net/dev; then
        IFACE=wlan3
    fi
fi

if [ -e /etc/default/batctl ]; then
    . /etc/default/batctl
fi

function global_rate_limit {
    if ! grep -q "tcp_challenge_ack_limit" /etc/sysctl.conf; then
        echo 'net.ipv4.tcp_challenge_ack_limit = 999999999' >> /etc/sysctl.conf
    else
        sed -i 's|net.ipv4.tcp_challenge_ack_limit.*|net.ipv4.tcp_challenge_ack_limit = 999999999|g' /etc/sysctl.conf
    fi
    sysctl -p
}

function status {
    batctl o
}

function stop {
    if [ -z "$IFACE" ]; then
        echo 'error: unable to find wifi interface, not enabling batman-adv mesh'
        return
    fi
    if [ "$EIFACE" ]; then
        brctl delif $BRIDGE bat0
        brctl delif $BRIDGE $EIFACE
        ifconfig $BRIDGE down || true
        brctl delbr $BRIDGE
        ifconfig $EIFACE down -promisc
    fi

    avahi-autoipd -k $BRIDGE
    avahi-autoipd -k $IFACE
    ifconfig bat0 down -promisc

    batctl if del $IFACE
    rmmod batman-adv
    ifconfig $IFACE mtu 1500
    ifconfig $IFACE down
    iwconfig $IFACE mode managed

    iptables -D INPUT -p tcp --dport 548 -j ACCEPT
    iptables -D INPUT -p udp --dport 548 -j ACCEPT
    iptables -D INPUT -p tcp --dport 5353 -j ACCEPT
    iptables -D INPUT -p udp --dport 5353 -j ACCEPT
    iptables -D INPUT -p tcp --dport 5354 -j ACCEPT
    iptables -D INPUT -p udp --dport 5354 -j ACCEPT
    iptables -D INPUT -p tcp --dport $ZERONET_PORT -j ACCEPT
    iptables -D INPUT -p udp --dport $ZERONET_PORT -j ACCEPT
    iptables -D INPUT -p tcp --dport $IPFS_PORT -j ACCEPT
    iptables -D INPUT -p udp --dport $SYNCTHING_PORT -j ACCEPT
    iptables -D INPUT -p tcp --dport $SYNCTHING_PORT -j ACCEPT

    systemctl restart network-manager
}

function verify {
    tempfile="$(mktemp)"
    batctl o > $tempfile
    if grep -q "disabled" $tempfile; then
        echo $'B.A.T.M.A.N. not enabled'
        rm $tempfile
        stop
        exit 726835
    fi
    echo $'B.A.T.M.A.N. is running'
    rm $tempfile
}

function assign_peer_address {
    for i in {1..6}; do
        number=$RANDOM
        let "number %= 255"
        octet=$(echo "obase=16;$number" | bc)
        if [ ${#octet} -lt 2 ]; then
            octet="0${octet}"
        fi
        if [ $i -gt 1 ]; then
            echo -n ":"
        fi
        echo -n "${octet}"
    done
    echo ''
}

function start {
    if [ -z "$IFACE" ] ; then
        echo 'error: unable to find wifi interface, not enabling batman-adv mesh'
        exit 723657
    fi
    echo "info: enabling batman-adv mesh network $WIFI_SSID on $IFACE"

    systemctl stop network-manager
    sleep 5

    # remove an avahi service which isn't used
    if [ -f /etc/avahi/services/udisks.service ]; then
        sudo rm /etc/avahi/services/udisks.service
    fi

    global_rate_limit

    # Might have to re-enable wifi
    rfkill unblock $(rfkill list|awk -F: "/phy/ {print $1}") || true

    ifconfig $IFACE down
    ifconfig $IFACE mtu 1532
    ifconfig $IFACE hw ether $(assign_peer_address)
    iwconfig $IFACE enc off
    iwconfig $IFACE mode ad-hoc essid $WIFI_SSID channel $CHANNEL
    sleep 1
    iwconfig $IFACE ap $CELLID

    modprobe batman-adv
    batctl if add $IFACE
    ifconfig $IFACE up
    avahi-autoipd --force-bind --daemonize --wait $BRIDGE
    avahi-autoipd --force-bind --daemonize --wait $IFACE
    ifconfig bat0 up promisc

    #Use persistent HWAddr
    ether_new=$(ifconfig eth0 | grep HWaddr | sed -e "s/.*HWaddr //")
    if [ ! -f /var/lib/mesh-node/bat0 ]; then
        mkdir /var/lib/mesh-node
        echo "${ether_new}" > /var/lib/mesh-node/bat0
    else
        ether=$(cat /var/lib/mesh-node/bat0)
        ifconfig bat0 hw ether ${ether}
    fi

    if [ "$EIFACE" ] ; then
        brctl addbr $BRIDGE
        brctl addif $BRIDGE bat0
        brctl addif $BRIDGE $EIFACE
        ifconfig bat0 0.0.0.0
        ifconfig $EIFACE 0.0.0.0
        ifconfig $EIFACE up promisc
        ifconfig $BRIDGE up
    fi

    iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
    iptables -A OUTPUT -p icmp --icmp-type echo-reply -j ACCEPT
    iptables -A INPUT -p tcp --dport 548 -j ACCEPT
    iptables -A INPUT -p udp --dport 548 -j ACCEPT
    iptables -A INPUT -p tcp --dport 5353 -j ACCEPT
    iptables -A INPUT -p udp --dport 5353 -j ACCEPT
    iptables -A INPUT -p tcp --dport 5354 -j ACCEPT
    iptables -A INPUT -p udp --dport 5354 -j ACCEPT
    iptables -A INPUT -p tcp --dport $ZERONET_PORT -j ACCEPT
    iptables -A INPUT -p udp --dport $ZERONET_PORT -j ACCEPT
    iptables -A INPUT -p tcp --dport $IPFS_PORT -j ACCEPT

    systemctl restart avahi-daemon

    verify
}

if ! grep -q "$IFACE" /proc/net/dev; then
    echo 'Interface $IFACE was not found'
    stop
    exit 1
fi

case "$1" in
    start|stop|status)
        $1
        ;;
    restart)
        stop
        sleep 10
        start
        ;;
    ping)
        batctl ping $2
        ;;
    ls|list)
        avahi-browse -atl
        ;;
    *)
        echo "error: invalid parameter $1"
        echo 'usage: $0 {start|stop|restart|status|ping|ls|list}'
        exit 2
        ;;
esac
exit 0