set-static-ip

#!/bin/bash
#
# Sets a static local IP address for the TinyPilot device.

# Exit on first error.
set -e

print_help() {
  cat << EOF
Usage: ${0##*/} --router router_ip --ip static_ip [--dns dns_ip]...
[--interface name]

Sets a static local IP address for the TinyPilot device.
  --router router_ip: The IP address of the local router (e.g., 10.0.0.1).
  --ip static_ip:     The static IP address to assign to the TinyPilot device
                      (e.g., 10.0.0.50).
  --dns dns_ip:       Optional. A DNS server to use to resolve domain names
                      (e.g., 8.8.8.8). Multiple DNS servers can be provided. If
                      unspecified, defaults to the router's DNS, then Google
                      (8.8.8.8), then Cloudflare (1.1.1.1).
  --interface name:   Optional. The interface to configure (e.g., eth0).
                      Defaults to eth0.
  --help:             Display this help text.

Note: there can only be one custom static IP configuration at a time. Running
      this script will clear any potentially existing custom configuration
      that might have been added previously by this script.

Examples:

1. Set static IP to 10.0.105 on a 10.0.0.x network.
set-static-ip \\
  --router 10.0.0.1 \\
  --ip 10.0.0.105

2. Configure wlan0 with a static IP of 192.168.1.100, with a Quad9 DNS server and a local fallback DNS server.
set-static-ip \\
  --router 192.168.1.1 \\
  --ip 192.168.1.100 \\
  --dns 9.9.9.9 \\
  --dns 192.168.1.1 \\
  --interface wlan0

EOF
}

print_help_nudge() {
  echo "For help on using this tool:" >&2
  echo "  set-static-ip --help" >&2
}

SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
readonly SCRIPT_DIR
readonly CONFIG_FILE="/etc/dhcpcd.conf"
# shellcheck source=lib/markers.sh
. "${SCRIPT_DIR}/lib/markers.sh"

# Parse command-line arguments.
if ! NEW_ARGS=$(getopt -q -o "" -l "ip:,router:,dns:,interface:" -- "$@"); then
  print_help
  exit 1
fi

# Process command-line arguments.
eval set -- "${NEW_ARGS}"
while true; do
  case "$1" in
    --ip)
      if [[ -z "${IP_ADDRESS}" ]] ; then
        readonly IP_ADDRESS="$2"
      else
        echo "Only one static IP address should be provided using --ip" >&2
        print_help_nudge
        exit 1
      fi
      shift 2
      ;;
    --router)
      if [[ -z "${ROUTERS}" ]] ; then
        readonly ROUTERS="$2"
      else
        echo "Only one router IP address should be provided using --router" >&2
        print_help_nudge
        exit 1
      fi
      shift 2
      ;;
    --dns)
      if [[ -z "${DNS}" ]] ; then
        DNS="$2"
      else
        DNS="${DNS} $2"
      fi
      shift 2
      ;;
    --interface)
      if [[ -z "${INTERFACE}" ]] ; then
        readonly INTERFACE="$2"
      else
        echo "Only one interface should be provided using --interface" >&2
        print_help_nudge
        exit 1
      fi
      shift 2
      ;;
    --)
      shift
      break
      ;;
  esac
done

# There must be at least a static IP address and a router IP address.
if [[ -z "${IP_ADDRESS}" ]] ; then
  echo "You must specify an IP address using --ip" >&2
  print_help_nudge
  exit 1
fi

if [[ -z "${ROUTERS}" ]] ; then
  echo "You must specify a router IP address using --router" >&2
  print_help_nudge
  exit 1
fi

# Default DNS settings.
if [[ -z "${DNS}" ]] ; then
  DNS="${ROUTERS} 8.8.8.8 1.1.1.1"
fi
readonly DNS

# Default interface.
if [[ -z "${INTERFACE}" ]] ; then
  readonly INTERFACE="eth0"
fi

# Exit on unset variable.
set -u

# Determine which version of the OS is running.
OS_VERSION="$(lsb_release --release --short)"
readonly OS_VERSION

if (( "${OS_VERSION}" == 11 )); then
  # Remove any existing automated configuration.
  "${SCRIPT_DIR}/strip-marker-sections" "${CONFIG_FILE}"

  # Only proceed if no other configuration exists.
  if grep -q "^interface ${INTERFACE}" "${CONFIG_FILE}" ; then
    echo "An existing configuration exists in ${CONFIG_FILE} for ${INTERFACE}." >&2
    echo "Please remove the existing configuration and try again." >&2
    exit 1
  fi

  # Write out the new configuration.
  {
    echo "${MARKER_START}"
    echo "interface ${INTERFACE}"
    echo "static ip_address=${IP_ADDRESS}"
    echo "static routers=${ROUTERS}"
    echo "static domain_name_servers=${DNS}"
    echo "${MARKER_END}"
  } | sudo tee --append "${CONFIG_FILE}" > /dev/null
else
  nmcli connection modify 'Wired connection 1' \
    ipv4.method manual \
    ipv4.addresses "${IP_ADDRESS}" \
    ipv4.gateway "${ROUTERS}" \
    ipv4.dns "${DNS}"
fi

# Apply changes.
"${SCRIPT_DIR}/apply-static-ip"

echo "A static local IP address has been set."
echo "  Interface: ${INTERFACE}"
echo "  IP Address: ${IP_ADDRESS}"
echo "  Routers: ${ROUTERS}"
echo "  Domain Name Servers: ${DNS}"