#!/bin/bash
# SPDX-Version: 3.0
# SPDX-CreationInfo: 2025-02-13; WEIDNER, Marc S.; <cendev@coresecret.eu>
# SPDX-ExternalRef: GIT https://cendev.eu/marc.weidner/CISS.2025.debian.installer.git
# SPDX-FileContributor: WEIDNER, Marc S.; Centurion Intelligence Consulting Agency
# SPDX-FileCopyrightText: 2024-2025; WEIDNER, Marc S.; <cendev@coresecret.eu>
# SPDX-FileType: SOURCE
# SPDX-License-Identifier: EUPL-1.2 OR LicenseRef-CCLA-1.0
# SPDX-LicenseComment: This file is part of the CISS.2025.hardened.installer framework.
# SPDX-PackageName: CISS.2025.hardened.installer
# SPDX-Security-Contact: security@coresecret.eu

###########################################################################################
# 3.7.8. Functions - installation - setup network                                         #
###########################################################################################
# TODO collect Gateway and convert CCDIR ot n.n.n.n
###########################################################################################
# Setup network
# Globals:
#   FINAL_FQDN
#   FINAL_IPV4_ADDRESS
#   FINAL_IPV6
#   FINAL_IPV6_ADDRESS
#   LOG_NIC
#   MODULE_ERR
#   MODULE_TXT
#   TARGET
#   network_autoconfig_enable
#   network_choose_interface_auto
#   network_choose_interface_static
#   network_ipv6
#   network_static_hostname
#   network_static_ipv4address
#   network_static_ipv4gateway
#   network_static_ipv4nameserver_0
#   network_static_ipv4nameserver_1
#   network_static_ipv4nameserver_fallback_0
#   network_static_ipv4netmask
#   network_static_ipv6address
#   network_static_ipv6gateway
#   network_static_ipv6nameserver_0
#   network_static_ipv6nameserver_1
#   network_static_ipv6nameserver_fallback_0
#   network_static_ipv6netmask
#   network_timeout_dhcp
# Arguments:
#   None
###########################################################################################
3_7_8_functions_installation_setup_network() {
  declare -g -x MODULE_ERR="3_7_8_functions_installation_setup_network"
  declare -g -x MODULE_TXT="Setup network"
  do_show_header "${MODULE_TXT}"

  # Initialize variables
  declare ADDR_GI=""
  declare ADDR_SI=""
  declare ADDR_YI=""
  declare DHCP_SRV=""
  declare FQDN=""
  declare HAS_NIC=""
  declare HAS_IPV4=""
  declare HAS_IPV6=""
  declare HAS_IPV4_CCIDR=""
  declare HAS_IPV6_CCIDR=""
  declare HAS_LINKIPV4=""
  declare HAS_LINKIPV6=""
  declare NIC=""

  # Check current network connection and configure variables
  HAS_NIC=$(ip -o link show | awk -F': ' '/state UP/ {print $2; exit}')
  HAS_IPV4_CCIDR=$(ip -4 -o addr show "${HAS_NIC}" | awk '{print $4; exit}')
  HAS_IPV4_SUBNET=$(do_generate_subnet "${HAS_IPV4_CCIDR}")
  HAS_IPV4=$(echo "$HAS_IPV4_CCIDR" | awk -F'/' '{print $1}')
  HAS_IPV4_GATEWAY=$(ip route show default dev "${HAS_NIC}" | awk '/^default/ {print $3; exit}')
  HAS_IPV6_CCIDR=$(ip -6 -o addr show "${HAS_NIC}" | awk '/scope global/ {print $4; exit}')
  if [[ -n ${HAS_IPV6_CCIDR} ]]; then
    HAS_IPV6=$(echo "${HAS_IPV6_CCIDR}" | awk -F'/' '{print $1}')
  fi
  HAS_LINKIPV4=$(ping -q -c 1 -W 1 -4 debian.org > /dev/null 2>&1 && echo "true" || echo "false")
  HAS_LINKIPV6=$(ping -q -c 1 -W 1 -6 debian.org > /dev/null 2>&1 && echo "true" || echo "false")

  do_log "info" "false" "Live environment DHCP information collection: timeout='${network_timeout_dhcp}' seconds."

  dhclient -v -1 "${HAS_NIC}" 2>&1 | timeout "${network_timeout_dhcp}" dhcpdump -i "${HAS_NIC}" >> "${LOG_NIC}" || true
  awk 'BEGIN {RS="---------------------------------------------------------------------------"; \
    ORS="---------------------------------------------------------------------------"} \
    NF {last=$0} END {print last}' "${LOG_NIC}" > "${LOG_NIC}".tmp && mv "${LOG_NIC}".tmp "${LOG_NIC}"

  do_log "info" "false" "Live environment DHCP information collection: collection completed."

  # Extract 'FQDN' from '${LOG_NIC}'
  FQDN=$(awk -F 'Host name' '/Host name/ {print $2}' "${LOG_NIC}" | xargs)

  # Extract 'YIADDR' (Your IP Address) from '${LOG_NIC}'
  ADDR_YI=$(awk -F 'YIADDR:' '/YIADDR/ {print $2}' "${LOG_NIC}" | awk '{print $1}' | xargs)

  # Extract 'SIADDR' (Server IP Address) from '${LOG_NIC}'
  ADDR_SI=$(awk -F 'SIADDR:' '/SIADDR/ {print $2}' "${LOG_NIC}" | awk '{print $1}' | xargs)

  # Extract 'Server Identifier' from '${LOG_NIC}'
  DHCP_SRV=$(awk -F 'Server identifier' '/Server identifier/ {print $2}' "${LOG_NIC}" | xargs)

  # Extract 'GIADDR' (Gateway IP Address) from '${LOG_NIC}'
  ADDR_GI=$(awk -F 'GIADDR:' '/GIADDR/ {print $2}' "${LOG_NIC}" | awk '{print $1}' | xargs)

  do_log "info" "false" "Live environment network check: HAS_NIC='${HAS_NIC}'."
  do_log "info" "false" "Live environment network check: HAS_IPV4_CCIDR='${HAS_IPV4_CCIDR}'."
  do_log "info" "false" "Live environment network check: HAS_IPV4_SUBNET='${HAS_IPV4_SUBNET}'."
  do_log "info" "false" "Live environment network check: HAS_IPV4_GATEWAY='${HAS_IPV4_GATEWAY}'."
  do_log "info" "false" "Live environment network check: HAS_IPV6_CCIDR='${HAS_IPV6_CCIDR}'."
  do_log "info" "false" "Live environment network check: HAS_LINKIPV4='${HAS_LINKIPV4}'."
  do_log "info" "false" "Live environment network check: HAS_LINKIPV6='${HAS_LINKIPV6}'."
  do_log "info" "false" "Live environment network check: FQDN='${FQDN}'."
  do_log "info" "false" "Live environment network check: ADDR_YI='${ADDR_YI}'."
  do_log "info" "false" "Live environment network check: ADDR_SI='${ADDR_SI}'."
  do_log "info" "false" "Live environment network check: DHCP_SRV='${DHCP_SRV}'."
  do_log "info" "false" "Live environment network check: ADDR_GI='${ADDR_GI}'."

  # Create network configuration file header.
  if [[ -f "${TARGET}"/etc/network/interfaces ]]; then
    rm "${TARGET}"/etc/network/interfaces
    do_log "info" "false" "Existing '${TARGET}/etc/network/interfaces' removed."
  fi

  touch "${TARGET}"/etc/network/interfaces
  chmod 0644 "${TARGET}"/etc/network/interfaces
  cat << EOF >> "${TARGET}"/etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

EOF

  do_log "info" "false" "Header '${TARGET}/etc/network/interfaces' created."

  # Configure network interfaces based on 'preseed.yaml' and create network configuration files for IPv4.
  if [[ ${network_autoconfig_enable,,} == "true" && ${network_choose_interface_auto,,} == "true" ]]; then

    declare IFACE
    for IFACE in $(ls /sys/class/net || true); do
      if [[ -d "/sys/class/net/${IFACE}/device" ]]; then
        NIC="${IFACE}"
        break
      fi
    done

    if [[ -z ${NIC} ]]; then
      NIC="${network_choose_interface_static}"
      do_log "notice" "false" "No physical NIC detected automatically. Use the specified static NIC instead: '${network_choose_interface_static}'."
    else
      do_log "info" "false" "The first physical auto-detected NIC is: '${NIC}'."
    fi

    ### Reminder ###
    # auto:
    # For servers or systems with static interfaces that should always be available (e.g., eth0 on a server).
    # For configurations where the interface should be active regardless of the cable status.
    # allow-hotplug:
    # For systems with dynamic or removable network devices (e.g., laptops or USB adapters).
    # To avoid boot delays when interfaces are unavailable.

    cat << EOF >> "${TARGET}"/etc/network/interfaces
# The primary network interface IPv4
auto "${NIC}"
iface "${NIC}" inet dhcp

EOF

    do_log "info" "false" "IPv4 on the primary NIC: '${NIC}' configured with DHCP."

  elif [[ ${network_autoconfig_enable,,} == "true" && ${network_choose_interface_auto,,} == "false" ]]; then

    NIC="${network_choose_interface_static}"
    cat << EOF >> "${TARGET}"/etc/network/interfaces
# The primary network interface IPv4
auto "${NIC}"
iface "${NIC}" inet dhcp

EOF

    do_log "info" "false" "IPv4 on the primary NIC: '${NIC}' configured with DHCP."

  else

    do_log "warning" "false" "No NIC specified. 'network_choose_interface_static' was: '${network_choose_interface_static}'."

  fi

  if [[ ${network_autoconfig_enable,,} == "false" ]]; then

    cat << EOF >> "${TARGET}"/etc/network/interfaces
# The primary network interface IPv4
auto "${network_choose_interface_static}"
iface "${network_choose_interface_static}" inet static
    address "${network_static_ipv4address}"
    netmask "${network_static_ipv4netmask}"
    gateway "${network_static_ipv4gateway}"
    dns-nameservers "${network_static_ipv4nameserver_0}" "${network_static_ipv4nameserver_1}" "${network_static_ipv4nameserver_fallback_0}"

EOF

    do_log "info" "false" "IPv4 on the primary NIC: '${network_choose_interface_static}' configured manually."

  else

    do_log "error" "false" "Network autoconfiguration 'network_autoconfig_enable' must be either 'true' or 'false'."

  fi

  # Configure network interfaces based on 'preseed.yaml' and create network configuration files for IPv6.
  if [[ ${network_autoconfig_enable} == "true" && ${HAS_LINKIPV6} == "true" ]]; then

    cat << EOF >> "${TARGET}"/etc/network/interfaces
# The primary network interface IPv6
iface "${HAS_NIC}" inet6 dhcp

EOF

    do_log "info" "false" "IPv6 on the primary NIC: '${HAS_NIC}' configured with DHCP."

  fi

  if [[ ${network_autoconfig_enable,,} == "false" && ${network_ipv6,,} == "true" ]]; then

    cat << EOF >> "${TARGET}"/etc/network/interfaces
# The primary network interface IPv6
iface "${HAS_NIC}" inet6 static
    address "${network_static_ipv6address}"/"${network_static_ipv6netmask}"
    gateway "${network_static_ipv6gateway}"
    dns-nameservers "${network_static_ipv6nameserver_0}" "${network_static_ipv6nameserver_1}" "${network_static_ipv6nameserver_fallback_0}"

EOF

    do_log "info" "false" "IPv6 on the primary NIC: '${HAS_NIC}' configured manually."

  fi

  # Until now, neither 'NetworkManager' nor 'systemd-resolved' are installed.
  # Therefore, '/etc/resolv.conf' is updated, too.

  # Create '/etc/resolv.conf' IPv4 entries.
  if [[ -f "${TARGET}"/etc/resolv.conf ]]; then
    rm "${TARGET}"/etc/resolv.conf
    do_log "info" "false" "Existing '${TARGET}/etc/resolv.conf' removed."
  fi

  touch "${TARGET}"/etc/resolv.conf
  chmod 0644 "${TARGET}"/etc/resolv.conf
  cat << EOF >> "${TARGET}"/etc/resolv.conf
# Custom DNS IPv4 configuration for DHCP
nameserver ${network_static_ipv4nameserver_0}
nameserver ${network_static_ipv4nameserver_1}
nameserver ${network_static_ipv4nameserver_fallback_0}

EOF

  do_log "info" "false" "IPv4 nameserver at: '${TARGET}/etc/resolv.conf' configured manually."

  # Create '/etc/resolv.conf' IPv6 entries.
  if [[ ${network_autoconfig_enable,,} == "true" && ${HAS_LINKIPV6,,} == "true" ]]; then

    cat << EOF >> "${TARGET}"/etc/resolv.conf
# Custom DNS IPv6 configuration for DHCP
nameserver ${network_static_ipv6nameserver_0}
nameserver ${network_static_ipv6nameserver_1}
nameserver ${network_static_ipv6nameserver_fallback_0}

EOF

    do_log "info" "false" "IPv6 nameserver at: '${TARGET}/etc/resolv.conf' configured manually."

  elif [[ ${network_autoconfig_enable,,} == "false" && ${network_ipv6,,} == "true" ]]; then

    cat << EOF >> "${TARGET}"/etc/resolv.conf
# Custom DNS IPv6 configuration for DHCP
nameserver ${network_static_ipv6nameserver_0}
nameserver ${network_static_ipv6nameserver_1}
nameserver ${network_static_ipv6nameserver_fallback_0}

EOF

    do_log "info" "false" "IPv6 nameserver at: '${TARGET}/etc/resolv.conf' configured manually."

  fi

  # Ensure Internet Systems Consortium DHCP Client is not overwriting the static nameserver settings.
  if [[ ${network_autoconfig_enable,,} == "true" && ${HAS_LINKIPV6,,} == "true" ]]; then

    cat << EOF > "${TARGET}"/etc/dhcp/dhclient.conf
# Custom DNS IPv4 and IPv6 configuration for DHCP
supersede domain-name-servers \
${network_static_ipv4nameserver_0}, \
${network_static_ipv4nameserver_1}, \
${network_static_ipv4nameserver_fallback_0}, \
${network_static_ipv6nameserver_0}, \
${network_static_ipv6nameserver_1}, \
${network_static_ipv6nameserver_fallback_0};
EOF

    do_log "info" "false" "DHCP client configuration for IPv4 and IPv6 at: '${TARGET}/etc/dhcp/dhclient.conf' configured."

  elif [[ ${network_autoconfig_enable,,} == "false" && ${network_ipv6,,} == "true" ]]; then

    cat << EOF > "${TARGET}"/etc/dhcp/dhclient.conf
# Custom DNS IPv4 and IPv6 configuration for DHCP
supersede domain-name-servers \
${network_static_ipv4nameserver_0}, \
${network_static_ipv4nameserver_1}, \
${network_static_ipv4nameserver_fallback_0}, \
${network_static_ipv6nameserver_0}, \
${network_static_ipv6nameserver_1}, \
${network_static_ipv6nameserver_fallback_0};
EOF

    do_log "info" "false" "DHCP client configuration IPv4 and IPv6 at: '${TARGET}/etc/dhcp/dhclient.conf' configured."

  else

    cat << EOF > "${TARGET}"/etc/dhcp/dhclient.conf
# Custom DNS IPv4 only configuration for DHCP
supersede domain-name-servers \
${network_static_ipv4nameserver_0}, \
${network_static_ipv4nameserver_1}, \
${network_static_ipv4nameserver_fallback_0};
EOF

    do_log "info" "false" "DHCP client configuration IPv4 only at: '${TARGET}/etc/dhcp/dhclient.conf' configured."

  fi

  # Export hostname and IPv4 and IPv6 addresses for further processing according to dynamic results and preseed.yaml settings.
  if [[ ${network_autoconfig_enable,,} == "true" ]]; then

    declare -g -r -x FINAL_FQDN="${FQDN}"
    declare -g -r -x FINAL_IPV4_ADDRESS="${ADDR_YI}"

  elif [[ ${network_autoconfig_enable,,} == "false" ]]; then

    declare -g -r -x FINAL_FQDN="${network_static_hostname}"
    declare -g -r -x FINAL_IPV4_ADDRESS="${network_static_ipv4address}"

  fi

  if [[ ${network_autoconfig_enable,,} == "true" && ${HAS_LINKIPV6,,} == "true" ]]; then

    declare -g -r -x FINAL_IPV6_ADDRESS="${HAS_IPV6}"
    declare -g -r -x FINAL_IPV6="${HAS_LINKIPV6}"

  elif [[ ${network_autoconfig_enable,,} == "false" && ${network_ipv6,,} == "true" ]]; then

    declare -g -r -x FINAL_IPV6_ADDRESS="${network_static_ipv6address}"

  fi

  do_show_footer "${MODULE_TXT}"
}
# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=sh: