#!/bin/bash
# Copyright 2021 Google LLC
#
# 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.

# A list of functions which get executed for each bound DHCP lease.
# These are configured by the files included below.
# Shellcheck does not understand how this gets referenced
# shellcheck disable=SC2034
GBMC_BR_DHCP_HOOKS=()

# A dict of outstanding items that should prevent DHCP completion
declare -A GBMC_BR_DHCP_OUTSTANDING=()

# SC can't find this path during repotest
# shellcheck disable=SC1091
source /usr/share/network/lib.sh || exit
# SC can't find this path during repotest
# shellcheck disable=SC1091
source /usr/share/gbmc-br-lib.sh || exit

# Load configurations from a known location in the filesystem to populate
# hooks that are executed after each event.
gbmc_br_source_dir /usr/share/gbmc-br-dhcp || exit

# Write out the current PID and cleanup when complete
trap 'rm -f /run/gbmc-br-dhcp.pid' EXIT
echo "$$" >/run/gbmc-br-dhcp.pid

if [ "$1" = bound ]; then
  # Variable is from the environment via udhcpc6
  # shellcheck disable=SC2154
  echo "DHCPv6(gbmcbr): $ipv6/128" >&2

  pfx_bytes=()
  ip_to_bytes pfx_bytes "$ipv6"
  # Ensure we are a BMC and have a suffix nibble, the 0th index is reserved
  if (( pfx_bytes[8] != 0xfd || pfx_bytes[9] & 0xf == 0 )); then
    echo "Invalid address" >&2
    exit 1
  fi
  # Ensure we don't have more than a /80 address
  for (( i = 10; i < 16; ++i )); do
    if (( pfx_bytes[i] != 0 )); then
      echo "Invalid address" >&2
      exit 1
    fi
  done

  pfx="$(ip_bytes_to_str pfx_bytes)"
  gbmc_br_set_ip "$pfx" || exit

  if [ -n "${fqdn-}" ]; then
    echo "Using hostname $fqdn" >&2
    hostnamectl set-hostname "$fqdn" || true
  fi

  gbmc_br_run_hooks GBMC_BR_DHCP_HOOKS || exit

  # If any of our hooks had expectations we should fail here
  if [ "${#GBMC_BR_DHCP_OUTSTANDING[@]}" -gt 0 ]; then
    echo "Not done with DHCP process: ${!GBMC_BR_DHCP_OUTSTANDING[*]}" >&2
    exit 1
  fi

  # Ensure that the installer knows we have completed processing DHCP by
  # running a service that reports completion
  echo 'Start DHCP Done' >&2
  systemctl start dhcp-done@DONE --no-block
fi