#!/bin/sh

# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation, either version 2 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 General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc., 51
# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# Copyright (C) 2012-2017 Aleksander Morgado <aleksander@aleksander.es>

print_usage ()
{
    echo "usage: $0 [OPTIONS] [DEVICE] [COMMAND]"
}

help ()
{
    echo "Usage: qmi-network [OPTIONS] [DEVICE] [COMMAND]"
    echo
    echo "Simple network management of QMI devices"
    echo
    echo "Commands:"
    echo "  start             Start network connection"
    echo "  stop              Stop network connection"
    echo "  status            Query network connection status"
    echo
    echo "Options:"
    echo "  --profile=[PATH]  Use the profile in the specified path"
    echo "  --help            Show help options"
    echo "  --version         Show version"
    echo
    echo "Notes:"
    echo
    echo "   1) [DEVICE] is given as the full path to the cdc-wdm character"
    echo "   device, e.g.:"
    echo "      /dev/cdc-wdm0"
    echo
    echo "   2) The qmi-network script requires a profile to work. Unless"
    echo "   explicitly specified with \`--profile', the file is assumed to"
    echo "   be available in the following path:"
    echo "      /etc/qmi-network.conf"
    echo
    echo "   3) The APN to use should be configured in the profile, in the"
    echo "   following way (e.g. assuming APN is called 'internet'):"
    echo "      APN=internet"
    echo
    echo "   4) Optional APN user/password strings may be given in the following"
    echo "   way:"
    echo "      APN_USER=user"
    echo "      APN_PASS=password"
    echo
    echo "   5) If you want to instruct the qmi-network script to use the"
    echo "   qmi-proxy setup, you can do so by configuring the following line"
    echo "   in the profile:"
    echo "      PROXY=yes"
    echo
    echo "   6) Once the qmi-network script reports a successful connection"
    echo "   you still need to run a DHCP client on the associated WWAN network"
    echo "   interface."
    echo
}

version ()
{
    echo "qmi-network @VERSION@"
    echo "Copyright (2013-2017) Aleksander Morgado"
    echo "License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl-2.0.html>"
    echo "This is free software: you are free to change and redistribute it."
    echo "There is NO WARRANTY, to the extent permitted by law."
    echo
}

# Basic options
if [ $# -lt 2 ]; then
    if [ "$1" = "--help" ]; then
        help
        exit 0
    elif [ "$1" = "--version" ]; then
        version
        exit 0
    fi

    echo "error: missing arguments" 1>&2
    print_usage
    exit 255
fi

# Defaults
PROFILE_FILE=/etc/qmi-network.conf

# Device + Command with options; options given first
while [ $# -gt 2 ]; do
    OPT="$1"
    shift

    case "$OPT" in
        "--")
            break 2;;
        "--profile")
            if [ $# -gt 2 ]; then
                PROFILE_FILE="$1"
                shift
            else
                PROFILE_FILE=""
            fi
            ;;
        "--profile="*)
            PROFILE_FILE="${OPT#*=}";;
        *)
            echo >&2 "Invalid option: $OPT"
            print_usage
            exit 255;;
    esac
done

if [ -z "$PROFILE_FILE" ]; then
    echo "error: empty profile path given" 1>&2
    print_usage
    exit 255
fi

if [ $# -ne 2 ] || [ "$1" = '--*' ] || [ "$2" = '--*' ]; then
    echo "error: missing arguments" 1>&2
    print_usage
    exit 255
fi

DEVICE=$1
COMMAND=$2

STATE_FILE=/tmp/qmi-network-state-`basename $DEVICE`

load_profile ()
{
    if [ -f "$PROFILE_FILE" ]; then
        echo "Loading profile at ${PROFILE_FILE}..."
        . $PROFILE_FILE

        if [ -n "$APN" ]; then
            echo "    APN: $APN"
        else
            echo "    APN: unset"
        fi

        if [ -n "$APN_USER" ]; then
            echo "    APN user: $APN_USER"
        else
            echo "    APN user: unset"
        fi

        if [ -n "$APN_PASS" ]; then
            echo "    APN password: $APN_PASS"
        else
            echo "    APN password: unset"
        fi

        if [ "$PROXY" = "yes" ]; then
            echo "    qmi-proxy: $PROXY"
            PROXY_OPT='--device-open-proxy'
        else
            echo "    qmi-proxy: no"
        fi
    else
        echo "Profile at '$PROFILE_FILE' not found..."
    fi
}

save_state ()
{
    KEY=$1
    VAL=$2

    echo "Saving state at ${STATE_FILE}... ($KEY: $VAL)"

    if [ -f "$STATE_FILE" ]; then
        PREVIOUS=`cat $STATE_FILE`
        PREVIOUS=`echo "$PREVIOUS" | grep -v $KEY`
        if [ -n "$PREVIOUS" ]; then
            echo $PREVIOUS > $STATE_FILE
        else
            rm $STATE_FILE
        fi
    fi

    if [ -n "$VAL" ]; then
        echo "$KEY=\"$VAL\"" >> $STATE_FILE
    fi
}

load_state ()
{
    if [ -f "$STATE_FILE" ]; then
        echo "Loading previous state from ${STATE_FILE}..."
        . $STATE_FILE

        if [ -n "$CID" ]; then
            echo "    Previous CID: $CID"
        fi
        if [ -n "$PDH" ]; then
            echo "    Previous PDH: $PDH"
        fi
    fi
}

clear_state ()
{
    echo "Clearing state at ${STATE_FILE}..."
    rm -f $STATE_FILE
}

setup_data_format ()
{
    RUN_WDA=0

    # Read link layer protocol setup in the device

    DEVICE_DATA_FORMAT_CMD="qmicli -d $DEVICE --wda-get-data-format $PROXY_OPT"
    echo "Checking data format with '$DEVICE_DATA_FORMAT_CMD'..."
    if [ -n "$QMIDEBUG" ]; then
        DEVICE_DATA_FORMAT_OUT="\
[/dev/cdc-wdm1] Successfully got data format
                   QoS flow header: no
               Link layer protocol: '802-3'
  Uplink data aggregation protocol: 'disabled'
Downlink data aggregation protocol: 'disabled'
                     NDP signature: '0'
  Uplink data aggregation max size: '0'
Downlink data aggregation max size: '0'"
    else
        DEVICE_DATA_FORMAT_OUT=`$DEVICE_DATA_FORMAT_CMD`
    fi
    DEVICE_LLP=`echo "$DEVICE_DATA_FORMAT_OUT" | sed -n "s/.*Link layer protocol:.*'\(.*\)'.*/\1/p"`

    if [ -z "$DEVICE_LLP" ]; then
        echo "Device link layer protocol not retrieved: WDA unsupported" 1>&2
        return
    fi

    if [ "$DEVICE_LLP" != "802-3" -a "$DEVICE_LLP" != "raw-ip" ]; then
        echo "Device link layer protocol not retrieved: unexpected value reported: '$DEVICE_LLP'" 1>&2
        return
    fi
    echo "Device link layer protocol retrieved: $DEVICE_LLP"

    # Read link layer protocol setup in the kernel

    EXPECTED_DATA_FORMAT_CMD="qmicli -d $DEVICE --get-expected-data-format"
    echo "Getting expected data format with '$EXPECTED_DATA_FORMAT_CMD'..."
    if [ -n "$QMIDEBUG" ]; then
        EXPECTED_LLP="raw-ip"
    else
        EXPECTED_DATA_FORMAT_OUT=`$EXPECTED_DATA_FORMAT_CMD`
        if [ $? -eq 0 ]; then
            EXPECTED_LLP=$EXPECTED_DATA_FORMAT_OUT
            echo "Expected link layer protocol retrieved: $EXPECTED_LLP"
        else
            echo "Expected link layer protocol not retrieved: kernel unsupported" 1>&2
            EXPECTED_LLP="802-3"
            # The kernel doesn't support expected data format, so we change the
            # device data format instead
            RUN_WDA=1
        fi
    fi

    if [ "$EXPECTED_LLP" != "802-3" -a "$EXPECTED_LLP" != "raw-ip" ]; then
        echo "Expected link layer protocol not retrieved: unexpected value reported: '$EXPECTED_LLP'" 1>&2
        return
    fi

    if [ "$DEVICE_LLP" = "$EXPECTED_LLP" ]; then
        echo "Device and kernel link layer protocol match: $DEVICE_LLP"
        return
    fi

    if [ $RUN_WDA -eq 1 ]; then
        DEVICE_DATA_FORMAT_SET_CMD="qmicli -d $DEVICE --wda-set-data-format=$EXPECTED_LLP $PROXY_OPT"
        echo "Updating device link layer protocol with '$DEVICE_DATA_FORMAT_SET_CMD'..."
        if [ -n "$QMIDEBUG" ]; then
            DEVICE_DATA_FORMAT_SET_OUT="\
[/dev/cdc-wdm1] Successfully set data format
                        QoS flow header: no
                    Link layer protocol: '802-3'
       Uplink data aggregation protocol: 'disabled'
     Downlink data aggregation protocol: 'disabled'
                          NDP signature: '0'
Downlink data aggregation max datagrams: '0'
     Downlink data aggregation max size: '0'"
        else
            DEVICE_DATA_FORMAT_SET_OUT=`$DEVICE_DATA_FORMAT_SET_CMD`
        fi

        LLP=`echo "$DEVICE_DATA_FORMAT_SET_OUT" | sed -n "s/.*Link layer protocol:.*'\(.*\)'.*/\1/p"`
        if [ -z "$LLP" ]; then
            echo "Error updating Device link layer protocol" 1>&2
        else
            echo "New device link layer protocol retrieved: $LLP"
        fi
    else
        EXPECTED_DATA_FORMAT_SET_CMD="qmicli -d $DEVICE --set-expected-data-format=$DEVICE_LLP"
        echo "Updating kernel link layer protocol with '$EXPECTED_DATA_FORMAT_SET_CMD'..."
        EXPECTED_DATA_FORMAT_SET_OUT=`$EXPECTED_DATA_FORMAT_SET_CMD`
        if [ $? -eq 0 ]; then
            echo "Kernel link layer protocol updated"
        else
            echo "Error updating kernel link layer protocol " 1>&2
        fi
    fi
}

# qmicli -d /dev/cdc-wdm0 --wds-start-network --client-no-release-cid
# [/dev/cdc-wdm0] Network started
#   Packet data handle: 3634026241
# [/dev/cdc-wdm0] Client ID not released:
#   Service: 'wds'
#       CID: '80'
start_network ()
{
    if [ -n "$CID" ]; then
        USE_PREVIOUS_CID="--client-cid=$CID"
    fi

    if [ -n "$PDH" ]; then
        echo "error: cannot re-start network, PDH already exists" 1>&2
        exit 3
    fi

    setup_data_format

    START_NETWORK_ARGS="apn='$APN'"
    if [ -n "$APN_USER" ]; then
        START_NETWORK_ARGS="${START_NETWORK_ARGS},username='$APN_USER'"
        if [ -n "$APN_PASS" ]; then
            START_NETWORK_ARGS="${START_NETWORK_ARGS},password='$APN_PASS'"
        fi
    fi

    START_NETWORK_CMD="qmicli -d $DEVICE --wds-start-network=$START_NETWORK_ARGS $USE_PREVIOUS_CID --client-no-release-cid $PROXY_OPT"
    echo "Starting network with '$START_NETWORK_CMD'..."

    if [ -n "$QMIDEBUG" ]; then
        START_NETWORK_OUT="\
[/dev/cdc-wdm0] Network started
        Packet data handle: '3634026241'
[/dev/cdc-wdm0] Client ID not released:
        Service: 'wds'
        CID: '80'"
    else
        START_NETWORK_OUT=`$START_NETWORK_CMD`
    fi

    # Save the new CID if we didn't use any before
    if [ -z "$CID" ]; then
        CID=`echo "$START_NETWORK_OUT" | sed -n "s/.*CID.*'\(.*\)'.*/\1/p"`
        if [ -z "$CID" ]; then
            echo "error: network start failed, client not allocated" 1>&2
            exit 1
        else
            save_state "CID" $CID
        fi
    fi

    PDH=`echo "$START_NETWORK_OUT" | sed -n "s/.*handle.*'\(.*\)'.*/\1/p"`
    if [ -z "$PDH" ]; then
        echo "error: network start failed, no packet data handle" 1>&2
        # Cleanup the client
        qmicli -d "$DEVICE" --wds-noop --client-cid="$CID" $PROXY_OPT
        clear_state
        exit 2
    else
        save_state "PDH" $PDH
    fi

    echo "Network started successfully"
}

# qmicli -d /dev/cdc-wdm0 --wds-stop-network
stop_network ()
{
    if [ -z "$CID" ]; then
        echo "Network already stopped"
    elif [ -z "$PDH" ]; then
        echo "Network already stopped; need to cleanup CID $CID"
        # Cleanup the client
        qmicli -d "$DEVICE" --wds-noop --client-cid="$CID" $PROXY_OPT
    else
        STOP_NETWORK_CMD="qmicli -d $DEVICE --wds-stop-network=$PDH --client-cid=$CID $PROXY_OPT"
        echo "Stopping network with '$STOP_NETWORK_CMD'..."

        if [ -n "$QMIDEBUG" ]; then
            STOP_NETWORK_OUT="\
[/dev/cdc-wdm0] Network stopped
"
        else
            STOP_NETWORK_OUT=`$STOP_NETWORK_CMD`
        fi

        echo "Network stopped successfully"
    fi

    clear_state
}

# qmicli -d /dev/cdc-wdm0 --wds-get-packet-service-status
packet_service_status ()
{
    if [ -n "$CID" ]; then
        USE_PREVIOUS_CID="--client-cid=$CID --client-no-release-cid"
    fi

    STATUS_CMD="qmicli -d $DEVICE --wds-get-packet-service-status $USE_PREVIOUS_CID $PROXY_OPT"
    echo "Getting status with '$STATUS_CMD'..."

    if [ -n "$QMIDEBUG" ]; then
        STATUS_OUT="\
[/dev/cdc-wdm0] Connection status: 'disconnected'
"
    else
        STATUS_OUT=`$STATUS_CMD`
    fi

    CONN=`echo "$STATUS_OUT" | sed -n "s/.*Connection status:.*'\(.*\)'.*/\1/p"`
    if [ -z "$CONN" ]; then
        echo "error: couldn't get packet service status" 1>&2
        exit 2
    else
        echo "Status: $CONN"
        if [ "$CONN" != "connected" ]; then
            exit 64
        fi
    fi
}

# Main

# Load profile, if any
load_profile

# Load previous state, if any
load_state

# Process commands
case $COMMAND in
    "start")
        start_network
        ;;
    "stop")
        stop_network
        ;;
    "status")
        packet_service_status
        ;;
    *)
        echo "error: unexpected command '$COMMAND'" 1>&2
        print_usage
        exit 255
        ;;
esac

exit 0