#!/bin/sh -

distrosysconfdir="@LXC_DISTRO_SYSCONF@"
localstatedir="@LOCALSTATEDIR@"
varrun="@RUNTIME_PATH@/lxc"

# These can be overridden in @LXC_DISTRO_SYSCONF@/lxc
#   or in @LXC_DISTRO_SYSCONF@/lxc-net

USE_LXC_BRIDGE="true"
LXC_BRIDGE="lxcbr0"
LXC_ADDR="10.0.3.1"
LXC_NETMASK="255.255.255.0"
LXC_NETWORK="10.0.3.0/24"
LXC_DHCP_RANGE="10.0.3.2,10.0.3.254"
LXC_DHCP_MAX="253"
LXC_DHCP_CONFILE=""
LXC_DOMAIN=""

[ ! -f $distrosysconfdir/lxc ] || . $distrosysconfdir/lxc

if [ -d "$localstatedir"/lock/subsys ]; then
    lockdir="$localstatedir"/lock/subsys
else
    lockdir="$localstatedir"/lock
fi

_netmask2cidr ()
{
    # Assumes there's no "255." after a non-255 byte in the mask
    local x=${1##*255.}
    set -- 0^^^128^192^224^240^248^252^254^ $(( (${#1} - ${#x})*2 )) ${x%%.*}
    x=${1%%$3*}
    echo $(( $2 + (${#x}/4) ))
}

ifdown() {
    which ifconfig >/dev/null 2>&1
    if [ $? = 0 ]; then
        ifconfig $1 down
        return
    fi
    which ip >/dev/null 2>&1
    if [ $? = 0 ]; then
        ip link set dev $1 down
    fi
}

ifup() {
    which ifconfig >/dev/null 2>&1
    if [ $? = 0 ]; then
        ifconfig $1 $2 netmask $3 up
        return
    fi
    which ip >/dev/null 2>&1
    if [ $? = 0 ]; then
        MASK=`_netmask2cidr ${LXC_NETMASK}`
        CIDR_ADDR="${LXC_ADDR}/${MASK}"
        ip addr add ${CIDR_ADDR} dev $1
        ip link set dev $1 up
    fi
}

start() {
    [ ! -f "${lockdir}"/lxc-net ] || { exit 0; }

    [ "x$USE_LXC_BRIDGE" = "xtrue" ] || { exit 0; }

    use_iptables_lock="-w"
    iptables -w -L -n > /dev/null 2>&1 || use_iptables_lock=""
    cleanup() {
        # dnsmasq failed to start, clean up the bridge
        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p udp --dport 67 -j ACCEPT
        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p tcp --dport 67 -j ACCEPT
        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p udp --dport 53 -j ACCEPT
        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p tcp --dport 53 -j ACCEPT
        iptables $use_iptables_lock -D FORWARD -i ${LXC_BRIDGE} -j ACCEPT
        iptables $use_iptables_lock -D FORWARD -o ${LXC_BRIDGE} -j ACCEPT
        iptables $use_iptables_lock -t nat -D POSTROUTING -s ${LXC_NETWORK} ! -d ${LXC_NETWORK} -j MASQUERADE || true
        iptables $use_iptables_lock -t mangle -D POSTROUTING -o ${LXC_BRIDGE} -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill
        ifdown ${LXC_BRIDGE}
        brctl delbr ${LXC_BRIDGE} || true
    }

    if [ -d /sys/class/net/${LXC_BRIDGE} ]; then
        exit 0;
    fi

    # set up the lxc network
    brctl addbr ${LXC_BRIDGE} || { echo "Missing bridge support in kernel"; stop; exit 0; }
    echo 1 > /proc/sys/net/ipv4/ip_forward

    # if we are run from systemd on a system with selinux enabled,
    # the mkdir will create /run/lxc as init_var_run_t which dnsmasq
    # can't write its pid into, so we restorecon it (to var_run_t)
    if [ ! -d "${varrun}" ]; then
        mkdir -p "${varrun}"
        which restorecon >/dev/null 2>&1
        if [ $? = 0 ]; then
            restorecon "${varrun}"
        fi
    fi

    ifup ${LXC_BRIDGE} ${LXC_ADDR} ${LXC_NETMASK}
    iptables $use_iptables_lock -I INPUT -i ${LXC_BRIDGE} -p udp --dport 67 -j ACCEPT
    iptables $use_iptables_lock -I INPUT -i ${LXC_BRIDGE} -p tcp --dport 67 -j ACCEPT
    iptables $use_iptables_lock -I INPUT -i ${LXC_BRIDGE} -p udp --dport 53 -j ACCEPT
    iptables $use_iptables_lock -I INPUT -i ${LXC_BRIDGE} -p tcp --dport 53 -j ACCEPT
    iptables $use_iptables_lock -I FORWARD -i ${LXC_BRIDGE} -j ACCEPT
    iptables $use_iptables_lock -I FORWARD -o ${LXC_BRIDGE} -j ACCEPT
    iptables $use_iptables_lock -t nat -A POSTROUTING -s ${LXC_NETWORK} ! -d ${LXC_NETWORK} -j MASQUERADE
    iptables $use_iptables_lock -t mangle -A POSTROUTING -o ${LXC_BRIDGE} -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill

    LXC_DOMAIN_ARG=""
    if [ -n "$LXC_DOMAIN" ]; then
        LXC_DOMAIN_ARG="-s $LXC_DOMAIN -S /$LXC_DOMAIN/"
    fi
    dnsmasq $LXC_DOMAIN_ARG -u lxc-dnsmasq --strict-order --bind-interfaces --pid-file="${varrun}"/dnsmasq.pid --conf-file=${LXC_DHCP_CONFILE} --listen-address ${LXC_ADDR} --dhcp-range ${LXC_DHCP_RANGE} --dhcp-lease-max=${LXC_DHCP_MAX} --dhcp-no-override --except-interface=lo --interface=${LXC_BRIDGE} --dhcp-leasefile=/var/lib/misc/dnsmasq.${LXC_BRIDGE}.leases --dhcp-authoritative || cleanup
    touch "${varrun}"/network_up
    touch "${lockdir}"/lxc-net
}

stop() {
    [ "x$USE_LXC_BRIDGE" = "xtrue" ] || { exit 0; }

    [ -f "${varrun}/network_up" ] || { exit 0; }
    # if $LXC_BRIDGE has attached interfaces, don't shut it down
    ls /sys/class/net/${LXC_BRIDGE}/brif/* > /dev/null 2>&1 && exit 0;

    if [ -d /sys/class/net/${LXC_BRIDGE} ]; then
        use_iptables_lock="-w"
        iptables -w -L -n > /dev/null 2>&1 || use_iptables_lock=""
        ifdown ${LXC_BRIDGE}
        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p udp --dport 67 -j ACCEPT
        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p tcp --dport 67 -j ACCEPT
        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p udp --dport 53 -j ACCEPT
        iptables $use_iptables_lock -D INPUT -i ${LXC_BRIDGE} -p tcp --dport 53 -j ACCEPT
        iptables $use_iptables_lock -D FORWARD -i ${LXC_BRIDGE} -j ACCEPT
        iptables $use_iptables_lock -D FORWARD -o ${LXC_BRIDGE} -j ACCEPT
        iptables $use_iptables_lock -t nat -D POSTROUTING -s ${LXC_NETWORK} ! -d ${LXC_NETWORK} -j MASQUERADE || true
        iptables $use_iptables_lock -t mangle -D POSTROUTING -o ${LXC_BRIDGE} -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill
        pid=`cat "${varrun}"/dnsmasq.pid 2>/dev/null` && kill -9 $pid || true
        rm -f "${varrun}"/dnsmasq.pid
        brctl delbr ${LXC_BRIDGE}
    fi
    rm -f "${varrun}"/network_up
    rm -f "${lockdir}"/lxc-net
}

# See how we were called.
case "$1" in
    start)
        start
    ;;

    stop)
        stop
    ;;

    restart|reload|force-reload)
        $0 stop
        $0 start
    ;;

    *)
        echo "Usage: $0 {start|stop|restart|reload|force-reload}"
        exit 2
esac

exit $?