#!/usr/bin/env bash

# -------------------------------------------------------------------------- #
# Copyright 2002-2021, OpenNebula Project, OpenNebula Systems                #
#                                                                            #
# Licensed under the Apache License, Version 2.0 (the "License"); you may    #
# not use this file except in compliance with the License. You may obtain    #
# a copy of the License at                                                   #
#                                                                            #
# http://www.apache.org/licenses/LICENSE-2.0                                 #
#                                                                            #
# Unless required by applicable law or agreed to in writing, software        #
# distributed under the License is distributed on an "AS IS" BASIS,          #
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   #
# See the License for the specific language governing permissions and        #
# limitations under the License.                                             #
#--------------------------------------------------------------------------- #

#
# network module implementation
#

is_network_supported()
{
    case "${os_id}" in
        alpine)
            return 0
            ;;
        debian|ubuntu|devuan)
            return 0
            ;;
    esac

    return 1
}

configure_network()
{
    gen_resolvconf
    gen_network_configuration > /etc/network/interfaces
}

stop_network()
{
    case "${os_id}" in
        alpine)
            service networking stop || true

            for _iface in $(get_interfaces); do
                if [ "${_iface}" != 'lo' ]; then
                    /sbin/ip link set dev "${_iface}" down || true
                    /sbin/ip addr flush dev "${_iface}" || true
                fi
            done
            ;;
        debian|ubuntu|devuan)
            if [ -f "/usr/sbin/ifreload" ] ; then
                return 0
            fi

            for _iface in $(get_interfaces); do
                if [ "${_iface}" != 'lo' ] ; then
                    /sbin/ifdown "${_iface}"
                    /sbin/ip link set dev "${_iface}" down || true
                    /sbin/ip addr flush dev "${_iface}" || true
                fi
            done
            ;;
        *)
            exit 1
            ;;
    esac
}

start_network()
{
    case "${os_id}" in
        alpine)
            service networking start

            # alpine 3.16+ might fail to set the interface configuration of an interface that was removed
            # from /etc/network/interfaces. This results in the interface having a definition
            # in the configuration file, but no actual interface configuration.

            for _iface in $(get_interfaces); do
                ip link show "$_iface"  | grep -q 'state DOWN' && service networking restart && break
            done

            ;;
        debian|ubuntu|devuan)
            if [ -f "/usr/sbin/ifreload" ] ; then
                /usr/sbin/ifreload -a
                return 0
            fi

            for _iface in $(get_interfaces); do
                /sbin/ifup "${_iface}"
            done
            ;;
        *)
            exit 1
            ;;
    esac
}

reload_network()
{
    stop_network
    start_network
}

#
# helper functions
#

# TODO: remove global variables and get rid off exports
#
# to satisfy shellcheck SC2154:
export os_id
export ip
export network
export mask
export cidr
export ip6
export ip6_prefix_length
export ip6_ula
export mac
export dev
export mtu
export gateway
export ip6_gateway
export method
export ip6_method
export metric
export ip6_metric
export dns
export search_domains
export external
export detach
export all_nameservers
export all_search_domains

gen_iface_conf()
{
    cat <<EOT
iface ${dev} inet static
  address ${ip}
  network ${network}
  netmask ${mask}
EOT

    if [ -n "$gateway" ]; then
        echo "  gateway ${gateway}"

        if [ -n "$metric" ]; then
            echo "  metric ${metric}"
        fi
    fi

    # Add static routes
    if [ -n "${static_routes}" ]; then

        IFS=',' read -r -a routes <<< "$static_routes"

        for route in "${routes[@]}"
        do
            rsplit=( ${route} )
            dst="${rsplit[0]}"
            gw="${rsplit[2]}"

            echo "  up ip route add ${dst} via ${gw}"
        done

    fi

    # Add ONEGATE Proxy static route ip route replace 169.254.16.9 dev eth0
    if missing_onegate_proxy_route; then
        echo "  up ip route replace ${onegate_host} dev ${dev}"

        unset onegate_proxy_route_missing
    fi

    if [ -n "$mtu" ]; then
        echo "  mtu ${mtu}"
    fi

    echo ""
}

gen_dhcp_conf()
{
    echo "iface ${dev} inet dhcp"

    if [ -n "$mtu" ]; then
        case "${os_id}" in
            alpine)
                echo "  mtu ${mtu}"
                ;;
            debian|ubuntu|devuan)
                echo "  pre-up ip link set dev ${dev} mtu ${mtu}"
                ;;
            *)
                exit 1
                ;;
        esac
    fi

    echo ""
}

gen_alias_conf()
{
    cat <<EOT
iface ${dev} inet static
  address ${ip}
  network ${network}
  netmask ${mask}
EOT

echo ""
}

gen_iface6_conf()
{
    case "${os_id}" in
        alpine)
            cat <<EOT
iface ${dev} inet6 static
  address ${ip6}
  netmask ${ip6_prefix_length:-64}
  pre-up echo 0 > /proc/sys/net/ipv6/conf/${dev}/autoconf
  pre-up echo 0 > /proc/sys/net/ipv6/conf/${dev}/accept_ra
EOT
            ;;
        debian|ubuntu|devuan)
            cat <<EOT
iface ${dev} inet6 static
  address ${ip6}
  netmask ${ip6_prefix_length:-64}
  autoconf 0
  accept_ra 0
EOT
            ;;
    esac

    # On Alpine Linux when using IPv6 gateway/metric options,
    # they override the metric on IPv4 routes. We better configure
    # default route via up script.
    if [ "${os_id}" = 'alpine' ] && \
       [ -n "${ip6_gateway}" ] && [ -n "${ip6_metric}" ];
    then
        echo "  up ip -6 route add default via ${ip6_gateway} dev ${dev} metric ${ip6_metric}"

    elif [ -n "${ip6_gateway}" ]; then
        echo "  gateway ${ip6_gateway}"

        if [ -n "${ip6_metric}" ]; then
            echo "  metric ${ip6_metric}"
        fi
    fi

    if [ -n "${mtu}" ]; then
        case "${os_id}" in
            alpine)
                echo "  mtu ${mtu}"
                ;;
            debian|ubuntu|devuan)
                # Ignores "mtu x", IPv6-only interfaces would not be configured
                echo "  pre-up ip link set dev ${dev} mtu ${mtu}"
                echo "  pre-up echo ${mtu} > /proc/sys/net/ipv6/conf/${dev}/mtu"
                ;;
            *)
                exit 1
                ;;
        esac
    fi

    echo ""

    if [ -n "${ip6_ula}" ]; then
        cat <<EOT
iface ${dev} inet6 static
  address ${ip6_ula}
  netmask 64
EOT
    fi

    echo ""
}

gen_dhcp6_conf()
{
    if [ "${ip6_method}" = "auto" ] ; then
        echo "iface ${dev} inet6 auto"
    else
        echo "iface ${dev} inet6 dhcp"
    fi

    case "${os_id}" in
        alpine)
            if [ -n "${mtu}" ]; then
                echo "  mtu ${mtu}"
            fi

            echo "  pre-up echo 0 > /proc/sys/net/ipv6/conf/${dev}/use_tempaddr"
            ;;
        debian|ubuntu|devuan)
            # Privext might not be effective in "dhcp" mode, so we better
            # directly configure also sysctl parameters. Also, there might
            # be a race condition between activating IPv4 and IPv6 part of
            # interface if IPv4 is dhcp. As a aresult, IPv6 SLAAC privacy
            # address might appear. So, for safety we better drop any global
            # IPv6 addresses as part of pre-up.
            echo "  privext 0"
            echo "  pre-up echo 0 > /proc/sys/net/ipv6/conf/${dev}/use_tempaddr"
            echo "  pre-up ip -6 addr flush dev ${dev} scope global || /bin/true"

            if [ -n "${mtu}" ]; then
                # Ignores "mtu x", IPv6-only interfaces would not be configured
                echo "  pre-up ip link set dev ${dev} mtu ${mtu}"
                echo "  pre-up echo ${mtu} > /proc/sys/net/ipv6/conf/${dev}/mtu"
            fi
            ;;
        *)
            exit 1
            ;;
    esac

    echo ""
}

gen_alias6_conf()
{
    case "${os_id}" in
        alpine)
            cat <<EOT
iface ${dev} inet6 static
  address ${ip6}
  netmask ${ip6_prefix_length:-64}
EOT
            ;;
        debian|ubuntu|devuan)
            cat <<EOT
iface ${dev} inet6 static
  address ${ip6}
  netmask ${ip6_prefix_length:-64}
EOT
            ;;
    esac

    echo ""

    if [ -n "${ip6_ula}" ]; then
        cat <<EOT

iface ${dev} inet6 static
  address ${ip6_ula}
  netmask 64
EOT
    fi

    echo ""
}

gen_network_configuration()
{

    # since Ubuntu 22.04 and newer networkd systemd-networkd-wait-online
    # started to timeout+fail with NETCFG_TYPE='interfaces'
    _networkd_version=$(networkctl --version 2>/dev/null | head -1 | awk '{print $2}')
    if [ -n "$_networkd_version" ] && [ $_networkd_version -ge 249 ]; then
        systemctl disable --now systemd-networkd-wait-online.service
    fi

    cat <<EOT
# Generated by one-context
auto lo
iface lo inet loopback

EOT

    _context_interfaces=$(get_context_interfaces)

    for _iface in $_context_interfaces; do
        setup_iface_vars "$_iface"

        skip_interface && continue

        echo "auto ${dev}"

        case "${method}" in
            ''|static)
                [ -n "${ip}" ] && gen_iface_conf
                ;;
            dhcp)
                gen_dhcp_conf
                ;;
        esac

        case "${ip6_method}" in
            ''|static)
                [ -n "${ip6}" ] && gen_iface6_conf
                ;;
            auto|dhcp)
                gen_dhcp6_conf
                ;;
            disable)
                :
                ;;
        esac

        _aliases=$(get_interface_alias "$_iface")

        for _nic_alias in $_aliases ; do
            setup_ipadr_vars "$_nic_alias"
            setup_ip6adr_vars "$_nic_alias"
            setup_alias_vars "$_nic_alias"

            if [ -z "${detach}" ]; then
                if ! is_true "${external}" ; then
                    [ -n "${ip}"  ] && gen_alias_conf
                    [ -n "${ip6}" ] && gen_alias6_conf
                fi
            fi
        done
    done

    case "${os_id}" in
        debian|ubuntu|devuan)
            echo "source /etc/network/interfaces.d/*.cfg"
            ;;
    esac
}

# took from find_ifaces in the networking service
get_interfaces() {
    /sbin/ifquery --list -a
}