tests/gnrc_dhcpv6_client: dynamically adapt Kea config for >=1.7.10

tests/gnrc_dhcpv6_client/dhcpv6_server.sh

@@ -16,10 +16,49 @@ if ! command -v kea-dhcp6; then
   exit 1
 fi
 
+_sem_ver() {
+    major=$(echo "$1" | cut -d. -f1 | sed -e 's/^0\+//' -e 's/^$/0/')
+    minor=$(echo "$1" | cut -d. -f2 | sed -e 's/^0\+//' -e 's/^$/0/')
+    patch=$(echo "$1" | cut -d. -f3 | sed -e 's/^0\+//' -e 's/^$/0/')
+    echo "$(( major << 32 | minor << 8 | patch ))"
+}
+
+_kea_version_lesser_1_7_10() {
+    test "$(_sem_ver "$(kea-dhcp6 -v)")" -lt "$(_sem_ver "1.7.10")"
+    return $?
+}
+
 _dhcpv6_server() {
+    TMPDIR="$(mktemp -u | xargs dirname)/${APPLICATION}_kea"
+
+    # only used `mktemp` with dry-run above to get temp directory name, so we
+    # still need to create the directory
+    mkdir -p "${TMPDIR}"
+    if _kea_version_lesser_1_7_10; then
+        config=$2
+    else
+        # Top-level "Logging" config is not supported by Kea >=1.7.10, so move
+        # that config to Dhcp6 map, see
+        # https://kea.readthedocs.io/en/kea-1.7.10/arm/config.html#json-syntax
+        config="${TMPDIR}/kea-dhcp6.config"
+        convert_json="$(cat <<EOF
+import json
+
+with open('$2') as c:
+    config = json.load(c)
+logging = config.pop('Logging', None)
+if logging is not None:
+    config['Dhcp6'].update(logging)
+with open('$config', 'w') as c:
+    json.dump(config, c)
+EOF
+)"
+        python3 -c "$convert_json"
+    fi
     sleep 1 # sleep to let TAP become active
-    sudo kea-dhcp6 -p $1 -c $2
+    KEA_PIDFILE_DIR=${TMPDIR} KEA_LOCKFILE_DIR=${TMPDIR} \
+        kea-dhcp6 -p "$1" -c "$config"
 }
 
 # no need to kill from external, kea handles double instances gracefully
-_dhcpv6_server $1 $2 &
+_dhcpv6_server "$1" "$2" &