Use dig and fping generate multiple remotes for an AirVPN config, replacing existing remote(s), and ignoring IPs that aren't responding. Remotes are placed in order of lowest ping to highest.

airvpn_remotes.sh

#!/bin/bash

PACKAGE=$(basename "$0")

# check for missing packages
MISSING_DEP="no"
if ! command -v fping &> /dev/null; then
  echo "$PACKAGE: fping is not installed."
  MISSING_DEP="yes"
fi

if ! command -v dig &> /dev/null; then
  echo "$PACKAGE: dig is not installed."
  MISSING_DEP="yes"
fi

if [[ "$MISSING_DEP" == "yes" ]]; then
  exit 1
fi

display_usage() {
  echo "$PACKAGE"
  echo ""
  echo "Description:"
  echo "  Use dig and fping generate multiple remotes for an AirVPN config, replacing existing remote(s), and ignoring IPs that aren't responding. Remotes are placed in order of lowest ping to highest."
  echo ""
  echo "Usage:"
  echo "  $PACKAGE [--port=<int>] [--query=<fqdn>] [--ipv4] [--ipv6] [--remote-random] [--in-place] [input-file]"
  echo "  $PACKAGE -h | --help"
  echo ""
  echo "Options:"
  echo "  -h, --help                       Show this screen."
  echo "  -p <int>, --port=<fqdn>          Override the port supplied on each remote line [default: 443]."
  echo "  -q <fqdn>, --query=<fqdn>        Supply the DNS record you wish to query to use the IPs from [default: ca.all.vpn.airdns.org]."
  echo "  -s <ns>, --server=<ns>           The name server you wish to query the records against [default: ns1.airvpn.org]."
  echo "  -c <int>, --count=<int>          Change the amount of pings ran by fping for more accurate ping sorting [default: 4]."
  echo "  -4, --ipv4                       Only query IPv4."
  echo "  -6, --ipv6                       Only query IPv6."
  echo "  -r, --remote-random              Add remote-random to the AirVPN config (this will cause OpenVPN to randomize the server order when connecting)."
  echo "  -i<ext>, --in-place=<ext>        Edit the file in place (makes backup if extension supplied), ignored if no input file is supplied."
  echo ""
  echo "The first non-option argument is the name of the input file; if no input file is specified, then the standard input is read. All other non-option arguments after the first are ignored."
}

TEMP=$(getopt -o 'h46rp:q:c:s:i::' --long 'help,ipv4,ipv6,remote-random,port:,query:,count:,server:,in-place::' -n "$PACKAGE" -- "$@")

if [ $? -ne 0 ]; then
  display_usage
  exit 1
fi

eval set -- "$TEMP"
unset TEMP

QUERY="ca.all.vpn.airdns.org"
SERVER="ns1.airvpn.org"
PORT="443"
IN_PLACE="no"
BACKUP_EXT=""
REMOTE_RANDOM="no"
IPV4="no"
IPV6="no"
PING_COUNT="4"
while true; do
  case "$1" in
    '-h'|'--help')
      display_usage
      exit 0
    ;;
    '-4'|'--ipv4')
      IPV4="yes"
      shift
      continue
    ;;
    '-6'|'--ipv6')
      IPV6="yes"
      shift
      continue
    ;;
    '-r'|'--remote-random')
      REMOTE_RANDOM="yes"
      shift
      continue
    ;;
    '-q'|'--query')
      QUERY="$2"
      shift 2
      continue
    ;;
    '-p'|'--port')
      PORT="$2"
      shift 2
      continue
    ;;
    '-s'|'--server')
      SERVER="$2"
      shift 2
      continue
    ;;
    '-c'|'--count')
      PING_COUNT="$2"
      case $PING_COUNT in
        ''|*[!0-9]*)
          echo "$PACKAGE: count provided is not an integer"
          exit 1
        ;;
      esac
      shift 2
      continue
    ;;
    '-i'|'--in-place')
      IN_PLACE="yes"
      BACKUP_EXT="$2"
      shift 2
      continue
    ;;
    '--')
      shift
      break
    ;;
    *)
      echo 'Internal error!' >&2
      exit 1
    ;;
  esac
done

INPUT=""
INPUT_FILE=""
USE_INPUT="yes"
for arg; do
  if [[ "$INPUT_FILE" == "" ]]; then
    INPUT_FILE="$arg"
  fi
done

if [[ "$INPUT_FILE" != "" ]]; then
  INPUT="$(cat "$INPUT_FILE" 2>&1)"
  if [[ "$?" != "0" ]]; then
    echo "$PACKAGE: can't read $INPUT_FILE: $(echo "$INPUT" | sed "s/cat: $INPUT_FILE: //" )"
    exit 1
  fi
fi

# if no input file specified, get stdin, if no stdin only output new remotes and not updated config
if [[ "$INPUT_FILE" == "" ]]; then
  if [ -p /dev/stdin ]; then
    INPUT=$(cat -)
    IN_PLACE="no"
  else
    USE_INPUT="no"
  fi
fi

# set the record type for dig
RECORD_TYPE="ANY"
if [[ "$IPV4" == "yes" && "$IPV6" == "no" ]]; then
  RECORD_TYPE="A"
elif [[ "$IPV4" == "no" && "$IPV6" == "yes" ]]; then
  RECORD_TYPE="AAAA"
fi

# get a list of all IPs from that record
IPS=$(dig +time=3 +tries=1 +short "$RECORD_TYPE" "$QUERY" @"$SERVER" 2>&1)
if [[ "$?" != "0" ]]; then
  echo "$PACKAGE: error during dig lookup"
  echo "$IPS"
  exit 1
fi

# if dig gave us no results we can't really do anything, inform the user and exit
if [[ "$IPS" == "" ]]; then
  echo "$PACKAGE: dig query returned no results, try adjusting your query flag, use the default, or double check your DNS"
  exit 1
fi

# test the IPs for working IPs and sort the results by lowest ping,
RESULTS=$(fping -a --count="$PING_COUNT" --timeout=500 $IPS 2>&1 1>/dev/null | awk -F' +|/' '/min\/avg\/max/ {print $15 "ms", $1}' | sort -nk1)

if [[ "$RESULTS" == "" ]]; then
  echo "$PACKAGE: fping found no reachable IPs"
  exit 1
fi

# generate our remotes to be added to the config file
REMOTES=""
while IFS= read -r line; do
  IP=$(awk '{print $2}' <<< "$line")
  PING=$(awk '{print $1}' <<< "$line")
  if [[ "$REMOTES" == "" ]]; then
    REMOTES="remote $IP $PORT # $PING"
  else
    REMOTES="$REMOTES
remote $IP $PORT # $PING"
  fi
done <<< "$RESULTS"

# prepend remote-random directive if requested
if [[ "$REMOTE_RANDOM" == "yes" ]]; then
  REMOTES="remote-random
$REMOTES"
fi

# if no input file or stdin are provided, output the remotes we generated to stdout
if [[ "$USE_INPUT" == "no" ]]; then
  echo "$REMOTES"
  exit
fi

# remove remotes & remote-random
INPUT=$(echo "$INPUT" | sed -n '/remote-random.*$/!p')
INPUT=$(echo "$INPUT" | sed -n '/remote\ .*$/!p')

# prepend our generated remotes to the input config
INPUT="$REMOTES
$INPUT"

if [[ "$IN_PLACE" == "yes" ]]; then
  # user wants an inplace update, check if they want to backup the original and copy that before overwriting
  if [[ "$BACKUP_EXT" != "" ]]; then
    cp "$INPUT_FILE" "$INPUT_FILE.$BACKUP_EXT"
  fi
  echo "$INPUT" > "$INPUT_FILE"
else
  # output to stdout
  echo "$INPUT"
fi