#!/bin/bash

# Source Qubes library.
# shellcheck disable=SC1091
. /usr/lib/qubes/init/functions
set -ueo pipefail

add_link_route () {
    /sbin/ip -- route replace to unicast "$1" dev "$2" scope link
}

add_default_route () {
    /sbin/ip -- route replace to unicast default via "$1" dev "$2" onlink
}

readonly netvm_mac=fe:ff:ff:ff:ff:ff
configure_network () {
    local MAC="$1"
    local INTERFACE="$2"
    local ip="$3"
    local ip6="$4"
    local netmask="$5"
    local netmask6="$6"
    local gateway="$7"
    local gateway6="$8"
    local primary_dns="$9"
    local secondary_dns="${10}"
    local custom="${11}"

    /sbin/ip -- address replace "$ip/$netmask" dev "$INTERFACE"
    if [[ "$custom" = false ]]; then
        /sbin/ip -- neighbour replace to "$gateway" dev "$INTERFACE" \
            lladdr "$netvm_mac" nud permanent
    fi
    if [ -n "$ip6" ]; then
        /sbin/ip -- address replace "$ip6/$netmask6" dev "$INTERFACE"
        if [ -n "$gateway6" ] && [[ "$custom" = false ]]; then
            /sbin/ip -- neighbour replace to "$gateway6" dev "$INTERFACE" \
                lladdr "$netvm_mac" nud permanent
        fi
    fi
    /sbin/ip link set dev "$INTERFACE" group 1 up

    if [ -n "$gateway" ]; then
        add_link_route "$gateway" "$INTERFACE"
        if [ -n "$gateway6" ] && ! echo "$gateway6" | grep -q "^fe80:"; then
            add_link_route "$gateway6/$netmask6" "$INTERFACE"
        fi
        if ! qsvc disable-default-route ; then
            add_default_route "$gateway" "$INTERFACE"
            if [ -n "$gateway6" ]; then
                add_default_route "$gateway6" "$INTERFACE"
            fi
        fi
    fi

    if [ -z "$primary_dns" ] && [ -n "$gateway" ]; then
        primary_dns="$gateway"
    fi

    if ! is_protected_file /etc/resolv.conf ; then
        # workaround systemd-resolved stupidity
        # https://github.com/systemd/systemd/pull/21317
        if [ -h /etc/resolv.conf ]; then
            rm -f /etc/resolv.conf
        fi
        echo > /etc/resolv.conf
        if ! qsvc disable-dns-server ; then
            echo "nameserver $primary_dns" > /etc/resolv.conf
            echo "nameserver $secondary_dns" >> /etc/resolv.conf
        fi
    fi
    if [ -x /usr/bin/resolvectl ] && \
            systemctl is-enabled -q systemd-resolved.service && \
            ! qsvc disable-dns-server ; then
        resolvectl dns "$INTERFACE" "$primary_dns" "$secondary_dns"
    fi
}

configure_network_nm () {
    local MAC="$1"
    local INTERFACE="$2"
    local ip="$3"
    local ip6="$4"
    local netmask="$5"
    local netmask6="$6"
    local gateway="$7"
    local gateway6="$8"
    local primary_dns="$9"
    local secondary_dns="${10}"
    local custom="${11}"

    local prefix
    local prefix6
    local nm_config
    local ip4_nm_config
    local ip6_nm_config
    local uuid
    /sbin/ip link set dev "$INTERFACE" group 1

    prefix="$(get_prefix_from_subnet "$netmask")"
    prefix6="$netmask6"
    uuid="de85f79b-8c3d-405f-a652-${MAC//:/}"
    nm_config="/etc/NetworkManager/system-connections/qubes-uplink-$INTERFACE"
    cat > "$nm_config" <<__EOF__
[802-3-ethernet]
duplex=full

[ethernet]
mac-address=$MAC

[connection]
id=VM uplink $INTERFACE
uuid=$uuid
type=802-3-ethernet
__EOF__
    ip4_nm_config=""
    ip6_nm_config=""
    if ! qsvc disable-dns-server ; then
        ip4_nm_config="${ip4_nm_config}
dns=${primary_dns};${secondary_dns}"
    fi
    if ! qsvc disable-default-route ; then
        ip4_nm_config="${ip4_nm_config}
addresses1=$ip;$prefix;$gateway"
        if [ -n "$ip6" ]; then
            ip6_nm_config="${ip6_nm_config}
addresses1=$ip6;$prefix6;$gateway6"
        fi
    else
        ip4_nm_config="${ip4_nm_config}
addresses1=$ip;$prefix"
        if [ -n "$ip6" ]; then
            ip6_nm_config="${ip6_nm_config}
addresses1=$ip6;$prefix6"
        fi
    fi
    if [ -n "$ip4_nm_config" ]; then
        cat >> "$nm_config" <<__EOF__
[ipv4]
method=manual
may-fail=false
$ip4_nm_config
__EOF__
    else
        cat >> "$nm_config" <<__EOF__
[ipv4]
method=ignore
__EOF__
    fi

    if [ -n "$ip6_nm_config" ]; then
        cat >> "$nm_config" <<__EOF__
[ipv6]
method=manual
may-fail=false
$ip6_nm_config
__EOF__
    else
        cat >> "$nm_config" <<__EOF__
[ipv6]
method=ignore
__EOF__
    fi

    chmod 600 "$nm_config"
    # reload connection
    nmcli connection load "$nm_config" || :
    if [[ "$custom" = false ]]; then
        /sbin/ip -- neighbour replace to "$gateway" dev "$INTERFACE" \
            lladdr "$netvm_mac" nud permanent
    fi
    if [ -n "$gateway6" ]; then
        if [[ "$custom" = false ]]; then
            /sbin/ip -- neighbour replace to "$gateway6" dev "$INTERFACE" \
                lladdr "$netvm_mac" nud permanent
        fi
    fi
}

configure_qubes_ns() {
    gateway=$(qubesdb-read /qubes-netvm-gateway)
    #netmask=$(qubesdb-read /qubes-netvm-netmask)
    primary_dns=$(qubesdb-read /qubes-netvm-primary-dns 2>/dev/null || echo "$gateway")
    secondary_dns=$(qubesdb-read /qubes-netvm-secondary-dns)
    echo "NS1=$primary_dns" > /var/run/qubes/qubes-ns
    echo "NS2=$secondary_dns" >> /var/run/qubes/qubes-ns
    /usr/lib/qubes/qubes-setup-dnat-to-ns
}

qubes_ip_change_hook() {
    if [ -x /rw/config/qubes-ip-change-hook ]; then
        /rw/config/qubes-ip-change-hook
    fi
    # XXX: Backward compatibility
    if [ -x /rw/config/qubes_ip_change_hook ]; then
        /rw/config/qubes_ip_change_hook
    fi
}

have_qubesdb || exit 0

ACTION="$1"
INTERFACE="$2"

if [ -z "$INTERFACE" ]; then
    echo "Missing INTERFACE argument" >&2
    exit 1
fi

if [ "$ACTION" == "add" ]; then
    MAC="$(get_mac_from_iface "$INTERFACE")"
    prefix="/net-config/$MAC/"
    if [[ -n "$MAC" ]]; then
        # prefix begins with / so -- is not needed
        if /usr/bin/qubesdb-read "${prefix}custom" >/dev/null 2>&1; then
            custom=true
        elif [[ "$?" = '2' ]]; then
            custom=false
        else
            echo "Could not check if ${prefix}custom exists!" >&2
            exit 1
        fi
        if ip4=$(exec /usr/bin/qubesdb-read "${prefix}ip" 2>/dev/null); then
            :
        elif [[ "$?" = '2' ]]; then
            prefix=/qubes-
            ip4=$(exec /usr/bin/qubesdb-read "${prefix}ip")
        else
            echo "Could not check if /net-config/$MAC/ip exists!" >&2
            exit 1
        fi
        netmask=$(exec /usr/bin/qubesdb-read --default=255.255.255.255 "${prefix}netmask")
        gateway=$(exec /usr/bin/qubesdb-read "${prefix}gateway")
        if ip6=$(exec /usr/bin/qubesdb-read "${prefix}ip6" 2>/dev/null); then
            netmask6=$(exec /usr/bin/qubesdb-read --default=128 "${prefix}netmask6")
            gateway6=$(exec /usr/bin/qubesdb-read --default="" "${prefix}gateway6")
        elif [[ "$?" != '2' ]]; then
            echo 'Could not check if IPv6 is enabled' >&2
            exit 1
        else
            ip6='' netmask6=128 gateway6=''
        fi

        primary_dns=$(/usr/bin/qubesdb-read /qubes-primary-dns 2>/dev/null) || primary_dns=
        secondary_dns=$(/usr/bin/qubesdb-read /qubes-secondary-dns 2>/dev/null) || secondary_dns=
        /lib/systemd/systemd-sysctl \
            "--prefix=/net/ipv4/conf/all" \
            "--prefix=/net/ipv4/neigh/all" \
            "--prefix=/net/ipv6/conf/all" \
            "--prefix=/net/ipv6/neigh/all" \
            "--prefix=/net/ipv4/conf/$INTERFACE" \
            "--prefix=/net/ipv4/neigh/$INTERFACE" \
            "--prefix=/net/ipv6/conf/$INTERFACE" \
            "--prefix=/net/ipv6/neigh/$INTERFACE"

        if [ -n "$ip4" ]; then
            # If NetworkManager is enabled, let it configure the network
            if qsvc network-manager && [ -e /usr/bin/nmcli ]; then
                configure_network_nm "$MAC" "$INTERFACE" "$ip4" "$ip6" "$netmask" "$netmask6" "$gateway" "$gateway6" "$primary_dns" "$secondary_dns" "$custom"
            else
                configure_network "$MAC" "$INTERFACE" "$ip4" "$ip6" "$netmask" "$netmask6" "$gateway" "$gateway6" "$primary_dns" "$secondary_dns" "$custom"
            fi

            network=$(qubesdb-read /qubes-netvm-network 2>/dev/null) || network=
            if [ -n "$network" ]; then
                if ! qsvc disable-dns-server; then
                    configure_qubes_ns
                fi
                qubes_ip_change_hook
            fi
        fi
    fi
elif [ "$ACTION" == "remove" ]; then
    # make sure network is disabled, especially on shutdown, to prevent
    # leaks when firewall will get stopped too
    ip link set "$INTERFACE" down 2>/dev/null || :

    # If exists, we delete NetworkManager configuration file to prevent duplicate entries
    nm_config="/etc/NetworkManager/system-connections/qubes-uplink-$INTERFACE"
    rm -rf "$nm_config"
else
    echo "Invalid action '$ACTION'" >&2
    exit 1
fi