#!/bin/sh

# To paste, press Ctrl-D to finish: cat > /etc/hotplug.d/iface/50-certidude
# To test: ACTION=ifup INTERFACE=wan sh /etc/hotplug.d/iface/50-certidude

# TODO: renewal

AUTHORITY=certidude.@authority[0]

[ $ACTION == "ifup" ] || exit 0
[ $INTERFACE == "$(uci get $AUTHORITY.trigger)" ] || exit 0

# TODO: iterate over all authorities

URL=$(uci get $AUTHORITY.url)
GATEWAY=$(uci get $AUTHORITY.gateway)

COMMON_NAME=$(uci get $AUTHORITY.common_name)
if [ $? -ne 0 ]; then
     COMMON_NAME=$(uci get system.@system[0].hostname)
fi

KEY_PATH=$(uci get $AUTHORITY.key_path)
KEY_TYPE=$(uci get $AUTHORITY.key_type)
KEY_LENGTH=$(uci get $AUTHORITY.key_length)

CERTIFICATE_PATH=$(uci get $AUTHORITY.certificate_path)
REQUEST_PATH=$(uci get $AUTHORITY.request_path)
AUTHORITY_PATH=$(uci get $AUTHORITY.authority_path)

RED_LED=/sys/class/leds/$(uci get $AUTHORITY.red_led)
GREEN_LED=/sys/class/leds/$(uci get $AUTHORITY.green_led)

NTP_SERVERS=$(uci get system.ntp.server)

logger -t certidude -s "Fetching time from NTP servers: $NTP_SERVERS"
ntpd -q -n -d -p $NTP_SERVERS

logger -t certidude -s "Time is now: $(date)"

# If certificate file is there assume everything's set up
if [ -f $CERTIFICATE_PATH ]; then
    SERIAL=$(openssl x509 -in $CERTIFICATE_PATH -noout -serial | cut -d "=" -f 2 | tr [A-F] [a-f])
    logger -t certidude -s "Certificate with serial $SERIAL already exists in $CERTIFICATE_PATH, attempting to bring up VPN tunnel..."
    /etc/init.d/openvpn start
    /etc/init.d/ipsec start
    exit 0
fi

# Turn green off and red on
if [ -d $GREEN_LED ] && [ -d $RED_LED ]; then
    echo timer > $GREEN_LED/trigger
    echo 100 | tee $GREEN_LED/delay_*
    echo none > $RED_LED/trigger
fi


#########################################
### Generate private key if necessary ###
#########################################

if [ ! -f $KEY_PATH ]; then
    KEY_TEMP=$(mktemp -u)

    logger -t certidude -s "Generating RSA key for VPN..."
    if [ -d $GREEN_LED ]; then
        echo 250 | tee $GREEN_LED/delay_*
    fi

    openssl gen$KEY_TYPE -out $KEY_TEMP $KEY_LENGTH
    chmod 0600 $KEY_TEMP
    mv $KEY_TEMP $KEY_PATH
fi


############################
### Fetch CA certificate ###
############################

if [ ! -f $AUTHORITY_PATH ]; then
    AUTHORITY_TEMP=$(mktemp -u)

    logger -t certidude -s "Fetching CA certificate from $URL/api/certificate/"
    curl -f -s $URL/api/certificate/ > $AUTHORITY_TEMP
    if [ $? -ne 0 ]; then
        logger -t certidude -s "Failed to receive CA certificate, server responded: $(cat $AUTHORITY_TEMP)"

        if [ -d $GREEN_LED ] && [ -d $RED_LED ]; then
            echo none > $GREEN_LED/trigger
            echo timer > $RED_LED/trigger
            echo 100 | tee $RED_LED/delay_*
        fi

        exit 10
    fi

    openssl x509 -in $AUTHORITY_TEMP -noout
    if [ $? -ne 0 ]; then
        logger -t certidude -s "Received invalid CA certificate"

        if [ -d $GREEN_LED ] && [ -d $RED_LED ]; then
            echo none > $GREEN_LED/trigger
            echo timer > $RED_LED/trigger
            echo 250 | tee $RED_LED/delay_*
        fi

        exit 11
    fi

    mv $AUTHORITY_TEMP $AUTHORITY_PATH
fi

logger -t certidude -s "CA certificate md5sum: $(md5sum -b $AUTHORITY_PATH)"


#####################################
### Generate request if necessary ###
#####################################

if [ ! -f $REQUEST_PATH ]; then
    REQUEST_TEMP=$(mktemp -u)
    openssl req -new -sha256 -key $KEY_PATH -out $REQUEST_TEMP -subj "/CN=$COMMON_NAME"
    mv $REQUEST_TEMP $REQUEST_PATH
fi

logger -t certidude -s "Request md5sum is $(md5sum -b $REQUEST_PATH)"

# Wait for certificate
if [ -d $GREEN_LED ]; then
    echo 500 | tee $GREEN_LED/delay_*
fi

CERTIFICATE_TEMP=$(mktemp -u)

curl -f -L \
    -H "Content-Type: application/pkcs10" \
    --data-binary @$REQUEST_PATH \
    $URL/api/request/?autosign=true\&wait=yes > $CERTIFICATE_TEMP

# TODO: Loop until we get exitcode 0
# TODO: Use backoff time $((2\*X))

if [ $? -ne 0 ]; then
    echo "Failed to fetch certificate"

    if [ -d $GREEN_LED ] && [ -d $RED_LED ]; then
        echo none > $GREEN_LED/trigger
        echo timer > $RED_LED/trigger
        echo 500 | tee $RED_LED/delay_*
    fi

    exit 21
fi

# Verify certificate
openssl verify -CAfile $AUTHORITY_PATH $CERTIFICATE_TEMP

if [ $? -ne 0 ]; then
    logger -t certidude -s "Received bogus certificate!"

    if [ -d $GREEN_LED ] && [ -d $RED_LED ]; then
        echo none > $GREEN_LED/trigger
        echo timer > $RED_LED/trigger
        echo 1000 | tee $RED_LED/delay_*
    fi

    exit 22
fi

logger -t certidude -s "Certificate md5sum: $(md5sum -b $CERTIFICATE_TEMP)"

uci commit

mv $CERTIFICATE_TEMP $CERTIFICATE_PATH

# Restart services
/etc/init.d/ipsec start
/etc/init.d/openvpn start