detect-dhcp-interfaces

#!/bin/sh

set -e

if which netplan 1>&2 2>/dev/null; then
  ip -br link show up | awk '{print $1}' | while read -r int; do
    if netplan ip leases 2>/dev/null; then
      echo "${int} auto"
    else
      echo "${int} manual"
    fi
  done
  exit $?
fi

if which ifcfg 1>&2 2>/dev/null; then
  for file in /etc/sysconfig/network-scripts/ifcfg-*; do
    int="$(basename "$file" | sed s/ifcfg-//)"
    if grep -q ^BOOTPROTO=\"*dhcp "${file}"; then
      echo "${int} auto"
    else
      echo "${int} manual"
    fi
  done
  exit $?
fi

if which nmcli 1>&2 2>/dev/null; then
  nmcli --get-values UUID connection show --active | while read -r int; do
    echo "${int} $(nmcli --get-values ipv4.method connection show "${int}")"
  done
  exit $?
fi

echo "Unsupported network tool" >&2
exit 1