Hassle-free automatic IP renewer for what is known as "Technicolor AG plus VDNT-S Router VDSL2" or "Telecom Italia VDSL/Fibra modem".

agvtf-refresh-ip.sh

#!/usr/bin/env bash
# Technicolor AG plus VDNT-S Router VDSL2 - (ba)sh IP renewer
# This script logs into the router and refreshes the IP address by toggling on
# and off the "automatic connection" parameter.
# It *NEEDS* to be configured. Please keep reading.

# Disable globbing, die on undefined variables and errors
set -efu

# Configuration
# IP address of your router
readonly ROUTER_ADDRESS="192.168.1.1"

# There are three ways to specify the password to access your router.
# - Use the password in *plaintext*. (WARNING: potentially insecure)
# - Hash the following string in MD5, either
#   * manually, with:
#     echo -n 'admin:Technicolor Gateway:password' | md5sum
#   * or automatically, running this script with the parameter '-p'
# - Do the same, but using environment variables (ROUTER_PASSWORD=xxx ./script.sh).
[ -z ${ROUTER_PASSWORD+isset} ] &&
    ROUTER_PASSWORD=""

# End of configuration
readonly DEFAULT_REALM="Technicolor Gateway"
readonly AUTHSTRING_PATH="5c7b0fdd32ff96ac19193e89df9c0d9d" # MD5 hash of 'GET:/index_auth.lp'

croak() { echo >&2 "ERROR: $*"; exit 1; }
get_md5() { echo -n "$1" | md5sum | awk '{print $1}'; }

# Test for dependencies
for executable in md5sum awk cut grep curl tail; do
    command -v "$executable" >/dev/null 2>&1 ||
        croak "'$executable' not found in \$PATH"
done

# Allow to generate "secure" passwords using `-p`
if [ "${1:-}" == "-p" ]; then
    echo '** Password generation mode **'
    echo 'Please enter the authentication realm of your router:'
    read -p "[$DEFAULT_REALM] " realm
    echo 'Please enter the password of your router' \
         "(won't be displayed)"
    read -s password
    echo "*** Here's your encoded password. ***"
    echo 'Use it with an environment variable or by editing' \
         'the source of this script.'
    get_md5 "admin:${realm:-$DEFAULT_REALM}:$password"
    exit 0
fi

# Normal mode -- ensure that the password is not empty
[ -z "$ROUTER_PASSWORD" ] &&
    croak 'The specified password is empty!' \
          'Try running the script with `-p`.'

# Initiate the authentication procedure
echo -n "Retrieving authentication parameters: "

temp_storage="$(mktemp -d)"
trap "rm -rf $temp_storage" EXIT

req="$(
    curl -sLc "$temp_storage/cookies" "http://$ROUTER_ADDRESS" | \
    grep -Eo '(nonce|qop|realm) = "([^"]+)"'
)"

# Retrieve xAuth_SESSION_ID
read -r _ _ _ _ _ cookie_name cookie_value <<<"$(tail -n 1 $temp_storage/cookies)"

[ "$cookie_name" != "xAuth_SESSION_ID" ] &&
    croak "Can't find xAuth_SESSION_ID!"

unset cookie_name

echo -n 'xAuth '

# Retrieve QOP/nonce/realm
while read line; do
    var_name="$(echo "$line" | cut -d' ' -f1)"
    var_value="$(echo "$line" | cut -d' ' -f3- | grep -Eo '[^"]+')"
    # Bash magic
    declare $var_name="$var_value"
    echo -n "$var_name "
done <<<"$req"

echo

# Ensure that we got the required variables
[ -z ${nonce+isset} ] && croak 'ERROR: missing `nonce`'
[ -z ${qop+isset} ] && croak 'ERROR: missing `qop`'
[ -z ${realm+isset} ] && croak 'ERROR: missing `realm`'

# Generate the password hash
echo "Logging in..."

# Encode the password if it's not already an MD5 hash.
[ "${#ROUTER_PASSWORD}" -ne 32 ] &&
    ROUTER_PASSWORD="$(get_md5 "admin:$realm:$ROUTER_PASSWORD")"

# Generate the final MD5 hash
ROUTER_PASSWORD="$(get_md5 "$ROUTER_PASSWORD:$nonce:00000001:xyz:$qop:$AUTHSTRING_PATH")"

# Log in
req="$(
    curl -sic "$temp_storage/cookies" -b "$temp_storage/cookies" -XPOST \
        --data-urlencode "rn=$cookie_value" \
        --data-urlencode "hidepw=$ROUTER_PASSWORD" \
        "http://$ROUTER_ADDRESS/index_auth.lp"
)"

echo $req | grep -vq passwordko ||
    croak "Incorrect password!"

# We are now logged in, probably! Yay!
echo "Refreshing your IP address..."

toggle_wanStatus() {    
    curl -sb "$temp_storage/cookies" -XPOST \
        --data-urlencode "rn=$cookie_value" \
        "http://$ROUTER_ADDRESS/wanStatus.lp" | \
    grep -o "<td colspan='2'.*" | \
    cut -d'>' -f2 | cut -d'<' -f1
}

echo "Status:"

for i in 1 2; do
    toggle_wanStatus
done

echo "Done!"