#!/bin/sh

#
# update Cloudflare DNS records with current (dynamic) IP address
#    Script by Asif Bacchus <asif@bacchus.cloud>
#    Last modified: July 19, 2026
#    Version 3.0
#

### text formatting presets using tput
if command -v tput >/dev/null; then
  [ -z "$TERM" ] && export TERM=xterm
  bold=$(tput bold)
  cyan=$(tput setaf 6)
  err=$(tput bold)$(tput setaf 1)
  magenta=$(tput setaf 5)
  norm=$(tput sgr0)
  ok=$(tput setaf 2)
  warn=$(tput bold)$(tput setaf 3)
  yellow=$(tput setaf 3)
  width=$(tput cols)
else
  bold=""
  cyan=""
  err=""
  magenta=""
  norm=""
  ok=""
  warn=""
  yellow=""
  width=80
fi

getTimeStamp() {
  (date -u +"%Y-%m-%dT%H:%M:%SZ")
}

getHostname() {
  (hostname -s)
}

lowercase() {
  echo "$1" | tr '[:upper:]' '[:lower:]'
}

uppercase() {
  echo "$1" | tr '[:lower:]' '[:upper:]'
}

standardizeLogLevels() {
  LEVEL_TO_STANDARDIZE="$(lowercase "$1")"
  case "$LEVEL_TO_STANDARDIZE" in
  "critical" | "crit" | "fatal")
    echo "CRIT"
    ;;
  "error" | "err")
    echo "ERR"
    ;;
  "warning" | "warn")
    echo "WARN"
    ;;
  "information" | "info")
    echo "INFO"
    ;;
  "debug" | "verbose")
    echo "DEBUG"
    ;;
  *)
    echo "INFO"
    ;;
  esac
}

# modified syslog fmt: <ISO-8601 timestamp> <hostname> <tag>[pid]: [LEVEL:$2] [STATUS:$3] <MESSAGE:$1> (<OPERATION:$4>:<CODE:$5>)
writePlainTextLog() {
  # not enough information to generate a meaningful log message
  if [ -z "$1" ] || [ $# -lt 3 ]; then
    return
  fi

  printf "%s %s %s[%s]: [%s] [%s] %s (%s:%s)\n" \
    "$(getTimeStamp)" "$(getHostname)" "$LOG_PROGRAM_NAME" "$$" \
    "$(standardizeLogLevels "$2")" "$(uppercase "$3")" "$1" "${4:-UNSPECIFIED}" "${5:-0}" \
    >>"$logFile"
}

### functions
badParam() {
  if [ "$1" = "null" ]; then
    printf "\n%sERROR: '%s' cannot have a NULL (empty) value.\n" "$err" "$2"
    printf "%sPlease use '--help' for assistance.%s\n\n" "$cyan" "$norm"
    exit 1
  elif [ "$1" = "dne" ]; then
    printf "\n%sERROR: '%s %s'\n" "$err" "$2" "$3"
    printf "file or directory does not exist or is empty.%s\n\n" "$norm"
    exit 1
  elif [ "$1" = "errMsg" ]; then
    printf "\n%sERROR: %s%s\n\n" "$err" "$2" "$norm"
    exit 1
  fi
}

exitError() {
  case "$1" in
  3)
    errMsg="Unable to connect to Cloudflare servers. This is probably a temporary networking issue. Please try again later."
    ;;
  10)
    errMsg="Unable to auto-detect IP address. Try again later or supply the IP address to be used."
    ;;
  20)
    errMsg="Cloudflare authorized email address (cfEmail) is either null or undefined. Please check your Cloudflare credentials file."
    ;;
  21)
    errMsg="Cloudflare authorized API key (cfKey) is either null or undefined. Please check your Cloudflare credentials file."
    ;;
  22)
    errMsg="Cloudflare zone id (cfZoneId) is either null or undefined. Please check your Cloudflare credentials file."
    ;;
  25)
    errMsg="Cloudflare API error. Please review any 'CF-ERR:' lines in this log for details."
    ;;
  26)
    errMsg="${failedHostCount} host update(s) failed. Any 'CF-ERR:' lines noted in this log may help determine what went wrong."
    ;;
  *)
    writeLog error "An unspecified error occurred. (code: 99)"
    printf "%s[%s] -- Cloudflare DDNS update-script: completed with error(s) --%s\n" "$err" "$(stamp)" "$norm" >>"$logFile"
    exit 99
    ;;
  esac
  writeLog error "$errMsg" "$1"
  printf "%s[%s] -- Cloudflare DDNS update-script: completed with error(s) --%s\n" "$err" "$(stamp)" "$norm" >>"$logFile"
  exit "$1"
}

exitOK() {
  printf "%s[%s] -- Cloudflare DDNS update-script: completed successfully --%s\n" "$ok" "$(stamp)" "$norm" >>"$logFile"
  exit 0
}

# 1: cloudflare error object, 2: operation identifier
listCFErrors() {
  # extract error codes and messages in separate variables, replace newlines with underscores
  codes="$(printf "%s" "$1" | jq -r '.errors | .[] | .code' | tr '\n' '_')"
  messages="$(printf "%s" "$1" | jq -r '.errors | .[] | .message' | tr '\n' '_')"

  # iterate codes and messages, assemble into a coherent log message
  while [ -n "$codes" ] && [ -n "$messages" ]; do
    # get the first code and message in respective sets
    code="${codes%%_*}"
    message="${messages%%_*}"

    # update sets of codes and messages by removing the first item (above) in each set
    codes="${codes#*_}"
    messages="${messages#*_}"

    # output to log
    writePlainTextLog "${message}" "err" "fail" "$2" "$code"
  done
}

scriptExamples() {
  newline
  printf "Update Cloudflare DNS host A/AAAA records with current IP address.\n"
  printf "%sUsage: %s --records host.domain.tld[,host2.domain.tld,...] [parameters]%s\n\n" "$bold" "$scriptName" "$norm"
  textBlock "${magenta}--- usage examples ---${norm}"
  newline
  textBlockSwitches "${scriptName} -r myserver.mydomain.net"
  textBlock "Update Cloudflare DNS records for myserver.mydomain.net with the auto-detected public IP4 address. Credentials will be expected in the default location and the log will be written in the default location also."
  newline
  textBlockSwitches "${scriptName} -r myserver.mydomain.net -6"
  textBlock "Same as above, but update AAAA host records with the auto-detected public IP6 address."
  newline
  textBlockSwitches "${scriptName} -r myserver.mydomain.net,myserver2.mydomain.net -l /var/log/cfddns.log --nc"
  textBlock "Update DNS entries for both listed hosts using auto-detected IP4 address. Write a non-coloured log to '/var/log/cfddns.log'."
  newline
  textBlockSwitches "${scriptName} -r myserver.mydomain.net,myserver2.mydomain.net -l /var/log/cfddns.log --ip6 --ip fd21:7a62:2737:9c3a::a151"
  textBlock "Update DNS AAAA entries for listed hosts using the *specified* IP address. Write a colourful log to the location specified."
  newline
  textBlockSwitches "${scriptName} -r myserver.mydomain.net -c /root/cloudflare.creds -l /var/log/cfddns.log --ip 1.2.3.4"
  textBlock "Update DNS A entry for listed hostname with the provided IP address. Read cloudflare credentials file from specified location, save log in specified location."
  newline
  textBlockSwitches "${scriptName} -r myserver.mydomain.net -c /root/cloudflare.creds -l /var/log/cfddns.log -6 -i fd21:7a62:2737:9c3a::a151"
  textBlock "Exact same as above, but change the AAAA record. This is how you run the script once for IP4 and again for IP6."
  exit 0
}

scriptHelp() {
  newline
  printf "Update Cloudflare DNS host A/AAAA records with current IP address.\n"
  printf "%sUsage: %s --records host.domain.tld[,host2.domain.tld,...] [parameters]%s\n\n" "$bold" "$scriptName" "$norm"
  textBlock "The only required parameter is '--records' which is a comma-delimited list of hostnames to update. However, there are several other options which may be useful to implement."
  textBlock "Parameters are listed below and followed by a description of their effect. If a default value exists, it will be listed on the following line in (parentheses)."
  newline
  textBlock "${magenta}--- script related parameters ---${norm}"
  newline
  textBlockSwitches "-c | --cred | --creds | --credentials | -f (deprecated, backward-compatibility)"
  textBlock "Path to file containing your Cloudflare *token* credentials. Please refer to the repo README for more information on format, etc."
  textBlockDefaults "(${accountFile})"
  newline
  textBlockSwitches "-l | --log"
  textBlock "Path where the log file should be written."
  textBlockDefaults "(${logFile})"
  newline
  textBlockSwitches "--nc | --no-color | --no-colour"
  textBlock "Switch value. Disables ANSI colours in the log. Useful if you review the logs using a reader that does not parse ANSI colour codes."
  textBlockDefaults "(disabled: print logs in colour)"
  newline
  textBlockSwitches "--log-console"
  textBlock "Switch value. Output log to console (stdout) instead of a log file. Can be combined with --nc if desired."
  textBlockDefaults "(disabled: output to log file)"
  newline
  textBlockSwitches "--log-journal"
  textBlock "Switch value. Output a structured log entry to your journaling system instead of a log file. Implies --nc."
  textBlockDefaults "(disabled: output to log file)"
  newline
  textBlockSwitches "--no-log"
  textBlock "Switch value. Do not create a log (i.e. no console, no file). You will not have *any* output from the script if you choose this option, so you will not know if updates succeeded or failed."
  textBlockDefaults "(disabled: output to log file)"
  newline
  textBlockSwitches "-h | --help | -?"
  textBlock "Display this help screen."
  newline
  textBlockSwitches "--examples"
  textBlock "Show some usage examples."
  newline
  textBlock "${magenta}--- DNS related parameters ---${norm}"
  newline
  textBlockSwitches "-r | --record | --records"
  textBlock "Comma-delimited list of hostnames for which IP addresses should be updated in Cloudflare DNS. This parameter is REQUIRED. Note that this script will only *update* records, it will not create new ones. If you supply hostnames that are not already defined in DNS, the script will log a warning and will skip those hostnames."
  newline
  textBlockSwitches "-i | --ip | --ip-address | -a | --address"
  textBlock "New IP address for DNS host records. If you omit this, the script will attempt to auto-detect your public IP address and use that."
  newline
  textBlockSwitches "-4 | --ip4 | --ipv4"
  textBlock "Switch value. Update Host 'A' records (IP4) only. Note that this script can only update either A *or* AAAA records. If you need to update both, you'll have to run the script once in IP4 mode and again in IP6 mode. If you specify both this switch and the IP6 switch, the last one specified will take effect."
  textBlockDefaults "(enabled: update A records)"
  newline
  textBlockSwitches "-6 | --ip6 | --ipv6"
  textBlock "Switch value. Update Host 'AAAA' records (IP6) only. Note that this script can only update either A *or* AAAA records. If you need to update both, you'll have to run the script once in IP4 mode and again in IP6 mode. If you specify both this switch and the IP4 switch, the last one specified will take effect."
  textBlockDefaults "(disabled: update A records)"
  newline
  textBlock "Please refer to the repo README for more detailed information regarding this script and how to automate and monitor it."
  newline
  exit 0
}

stamp() {
  (date +%F" "%T)
}

newline() {
  printf "\n"
}

textBlock() {
  printf "%s\n" "$1" | fold -w "$width" -s
}

textBlockDefaults() {
  printf "%s%s%s\n" "$yellow" "$1" "$norm"
}

textBlockSwitches() {
  printf "%s%s%s\n" "$cyan" "$1" "$norm"
}

writeLog() {
  case "$1" in
  cf)
    printf "[%s] CF-ERR: %s (code: %s)\n" "$(stamp)" "$2" "$3" >>"$logFile"
    ;;
  err)
    printf "%s[%s] ERR: %s%s\n" "$err" "$(stamp)" "$2" "$norm" >>"$logFile"
    ;;
  error)
    printf "%s[%s] ERROR: %s (code: %s)%s\n" "$err" "$(stamp)" "$2" "$3" "$norm" >>"$logFile"
    ;;
  process)
    printf "%s[%s] %s... %s" "$cyan" "$(stamp)" "$2" "$norm" >>"$logFile"
    ;;
  process-done)
    printf "%s%s%s\n" "$cyan" "$2" "$norm" >>"$logFile"
    ;;
  process-error)
    printf "%sERROR%s\n" "$err" "$norm" >>"$logFile"
    ;;
  process-warning)
    printf "%s%s%s\n" "$warn" "$2" "$norm" >>"$logFile"
    ;;
  stamped)
    printf "[%s] %s\n" "$(stamp)" "$2" >>"$logFile"
    ;;
  success)
    printf "%s[%s] SUCCESS: %s%s\n" "$ok" "$(stamp)" "$2" "$norm" >>"$logFile"
    ;;
  warn)
    printf "%s[%s] WARN: %s%s\n" "$warn" "$(stamp)" "$2" "$norm" >>"$logFile"
    ;;
  warning)
    printf "%s[%s] WARNING: %s%s\n" "$warn" "$(stamp)" "$2" "$norm" >>"$logFile"
    ;;
  *)
    printf "%s\n" "$2" >>"$logFile"
    ;;
  esac
}

### default variable values
scriptPath="$(CDPATH='' \cd -- "$(dirname -- "$0")" && pwd -P)"
scriptName="$(basename "$0")"
logFile="$scriptPath/${scriptName%.*}.log"
logToJournal=0
accountFile="$scriptPath/cloudflare.credentials"
colourizeLogFile=1
dnsRecords=""
dnsSeparator=","
ipAddress=""
ip4=1
ip6=0
ip4DetectionSvc="http://ipv4.icanhazip.com"
ip6DetectionSvc="http://ipv6.icanhazip.com"
invalidDomainCount=0
failedHostCount=0

### process startup parameters
if [ -z "$1" ]; then
  scriptHelp
fi
while [ $# -gt 0 ]; do
  case "$1" in
  -h | -\? | --help)
  # display help
    scriptHelp
    ;;
  --examples)
  # display sample commands
    scriptExamples
    ;;
  -l | --log)
  # set log file location
    if [ -n "$2" ]; then
      logFile="${2%/}"
      shift
    else
      badParam null "$@"
    fi
    ;;
  --log-console)
  # log to the console instead of a file
    logFile="/dev/stdout"
    ;;
  --log-journal)
  # log to the journal system instead of a file
    logToJournal=1
    ;;
  --no-log)
  # do not log anything
    logFile="/dev/null"
    ;;
  --nc | --no-color | --no-colour)
  # do not colourize log file
    colourizeLogFile=0
    ;;
  -c | --cred* | -f)
  # path to Cloudflare credentials file
    if [ -n "$2" ]; then
      if [ -f "$2" ] && [ -s "$2" ]; then
        accountFile="${2%/}"
        shift
      else
        badParam dne "$@"
      fi
    else
      badParam null "$@"
    fi
    ;;
  -r | --record | --records)
  # DNS records to update
    if [ -n "$2" ]; then
      dnsRecords=$(printf "%s" "$2" | sed -e 's/ //g')
      shift
    else
      badParam null "$@"
    fi
    ;;
  -i | --ip | --ip-address | -a | --address)
  # IP address to use (not parsed for correctness)
    if [ -n "$2" ]; then
      ipAddress="$2"
      shift
    else
      badParam null "$@"
    fi
    ;;
  -4 | --ip4 | --ipv4)
  # operate in IP4 mode (default)
    ip4=1
    ip6=0
    ;;
  -6 | --ip6 | --ipv6)
  # operate in IP6 mode
    ip6=1
    ip4=0
    ;;
  *)
    printf "\n%sUnknown option: %s\n" "$err" "$1"
    printf "%sUse '--help' for valid options.%s\n\n" "$cyan" "$norm"
    exit 1
    ;;
  esac
  shift
done

### pre-flight checks
if ! command -v curl >/dev/null; then
  printf "\n%sThis script requires 'curl' be installed and accessible. Exiting.%s\n\n" "$err" "$norm"
  writePlainTextLog "'curl' must be installed and accessible" "fatal" "fail" "preexec" 2
  exit 2
fi
if ! command -v jq >/dev/null; then
  printf "\n%sThis script requires 'jq' be installed and accessible. Exiting.%s\n\n" "$err" "$norm"
  writePlainTextLog "'jq' must be installed and accessible" "fatal" "fail" "preexec" 2
  exit 2
fi
if [ -z "$dnsRecords" ]; then
  badParam errMsg "You must specify at least one DNS record to update. Exiting."
  writePlainTextLog "At least one DNS record to update must be specified" "fatal" "fail" "params" 1
fi
# verify the credentials file exists and is not empty (default check)
if [ ! -f "$accountFile" ] || [ ! -s "$accountFile" ]; then
  badParam errMsg "Cannot find the Cloudflare credentials file (${accountFile}). Exiting."
  writePlainTextLog "Cannot find the specified Cloudflare credentials file (${accountFile})" "fatal" "fail" "params" 1
fi
if [ "$logToJournal" -eq 1 ] && ! command -v logger >/dev/null 2>&1; then
  printf "\n%sThis script requires 'logger' be installed to write entries to your journaling system. Exiting.%s\n\n" "$err" "$norm"
  exit 2
fi
# turn off log file colourization if parameter is set
if [ "$colourizeLogFile" -eq 0 ]; then
  bold=""
  cyan=""
  err=""
  magenta=""
  norm=""
  ok=""
  warn=""
  yellow=""
fi

### initial log entries
writePlainTextLog "starting '${scriptName}'" "info" "ok" "script"
writePlainTextLog "script path: ${scriptPath}/${scriptName}" "debug" "ok" "startup"
writePlainTextLog "credentials file: ${accountFile}" "debug" "ok" "startup"

if [ "$ip4" -eq 1 ]; then
  writePlainTextLog "mode: IPv4" "debug" "ok" "startup"
elif [ "$ip6" -eq 1 ]; then
  writePlainTextLog "mode: IPv6" "debug" "ok" "startup"
fi

# detect and report IP address
if [ -z "$ipAddress" ]; then
  # detect public ip address
  if [ "$ip4" -eq 1 ]; then
    if ! ipAddress="$(curl -s $ip4DetectionSvc)"; then
      writePlainTextLog \
        "Unable to auto-detect this machine's public IP address; try again later or supply the IP address to be used" "err" "fail" "detectip" 10
      exit 10
    fi
  fi
  if [ "$ip6" -eq 1 ]; then
    if ! ipAddress="$(curl -s $ip6DetectionSvc)"; then
      writePlainTextLog \
        "Unable to auto-detect this machine's public IP address; try again later or supply the IP address to be used" "err" "fail" "detectip" 10
      exit 10
    fi
  fi
  writePlainTextLog "DDNS IP address (detected): $ipAddress" "info" "ok" "startup"
else
  writePlainTextLog "DDNS IP address (supplied): $ipAddress" "info" "ok" "startup"
fi

# iterate DNS records to update
dnsRecordsToUpdate="$(printf '%s' "${dnsRecords}" | sed "s/${dnsSeparator}*$//")$dnsSeparator"
while [ -n "$dnsRecordsToUpdate" ] && [ "$dnsRecordsToUpdate" != "$dnsSeparator" ]; do
  record="${dnsRecordsToUpdate%%${dnsSeparator}*}"
  dnsRecordsToUpdate="${dnsRecordsToUpdate#*${dnsSeparator}}"

  if [ -z "$record" ]; then
    continue
  fi
  writePlainTextLog "DNS host record '${record}' queued for update" "info" "ok" "startup"
done

### read Cloudflare credentials
case "$accountFile" in
/*)
# absolute path, use as-is
# shellcheck source=./cloudflare.credentials
  . "$accountFile"
  ;;
*)
# relative path, rewrite
# shellcheck source=./cloudflare.credentials
  . "./$accountFile"
  ;;
esac
if [ -z "$cfKey" ]; then
  writePlainTextLog "Cloudflare authorized API key (cfKey) is either null or undefined; please check your Cloudflare credentials file" "err" "fail" "creds" 21
  exit 21
fi
if [ -z "$cfZoneId" ]; then
  writePlainTextLog "Cloudflare zone id (cfZoneId) is either null or undefined; please check your Cloudflare credentials file" "err" "fail" "creds" 22
  exit 22
fi
writePlainTextLog "Cloudflare credentials file read successfully" "debug" "ok" "creds"

### connect to Cloudflare and do what needs to be done!
dnsRecordsToUpdate="$dnsRecords$dnsSeparator"
if [ "$ip4" -eq 1 ]; then
  recordType="A"
elif [ "$ip6" -eq 1 ]; then
  recordType="AAAA"
fi

# iterate hosts to update
while [ -n "$dnsRecordsToUpdate" ] && [ "$dnsRecordsToUpdate" != "$dnsSeparator" ]; do
  record="${dnsRecordsToUpdate%%${dnsSeparator}*}"
  dnsRecordsToUpdate="${dnsRecordsToUpdate#*${dnsSeparator}}"

  if [ -z "$record" ]; then
    continue
  fi

  # exit if curl/network error
  if ! cfLookup="$(
    curl -s -X GET "https://api.cloudflare.com/client/v4/zones/${cfZoneId}/dns_records?name=${record}&type=${recordType}" \
      -H "Authorization: Bearer ${cfKey}" \
      -H "Content-Type: application/json"
  )"; then
    writePlainTextLog "Unable to connect to Cloudflare servers; please try again later." "err" "fail" "cflogin" 3
    exit 3
  fi

  # an API error on this GET request likely indicates an authentication error that would affect all remaining operations
  # no reason to continue processing other dns records and pile-up errors which might look like a DoS attempt
  cfSuccess="$(printf "%s" "$cfLookup" | jq -r '.success')"
  if [ "$cfSuccess" = "false" ]; then
    listCFErrors "$cfLookup" "cflogin"
    writePlainTextLog "Cloudflare API error; review any previously logged 'CF-ERR:' lines for details." "err" "fail" "cflogin" 25
    exit 25
  fi

  resultCount="$(printf "%s" "$cfLookup" | jq '.result_info.count')"

  # skip to the next host if an existing host record cannot be found (this script *updates* only, does not create!)
  if [ "$resultCount" = "0" ]; then
    writePlainTextLog "Cannot find an existing record matching '${record}' to update" "warn" "warn" "ddns"
    invalidDomainCount=$((invalidDomainCount + 1))
    continue
  fi

  objectId=$(printf "%s" "$cfLookup" | jq -r '.result | .[] | .id')
  currentIpAddr=$(printf "%s" "$cfLookup" | jq -r '.result | .[] | .content')
  writePlainTextLog "The current IP address for '${record}' is ${currentIpAddr}" "debug" "ok" "ddns"

  # skip to next hostname if record already up to date
  if [ "$currentIpAddr" = "$ipAddress" ]; then
    writePlainTextLog "The IP address for '${record}' is already up to date" "info" "ok" "ddns"
    continue
  fi

  # update record
  updateJSON="$(jq -n --arg key0 content --arg value0 "${ipAddress}" '{($key0):$value0}')"

  # exit if curl/network error
  if ! cfResult="$(
    curl -s -X PATCH "https://api.cloudflare.com/client/v4/zones/${cfZoneId}/dns_records/${objectId}" \
      -H "Authorization: Bearer ${cfKey}" \
      -H "Content-Type: application/json" \
      --data "${updateJSON}"
  )"; then
    writePlainTextLog "Unable to connect to Cloudflare servers; please try again later." "err" "fail" "ddns" 3
    exit 3
  fi

  # note update success or failure
  cfSuccess="$(printf "%s" "$cfResult" | jq '.success')"
  if [ "$cfSuccess" = "true" ]; then
    writePlainTextLog "The IP address for '${record}' successfully updated" "info" "ok" "ddns"
  else
    listCFErrors "$cfResult" "ddns"
    writePlainTextLog "Unable to update the IP address for '${record}'" "err" "fail" "ddns"
    # do not exit with error, API error here is probably an update issue specific to this host
    # increment counter and note it after all processing finished
    failedHostCount=$((failedHostCount + 1))
  fi
done

# exit
if [ "$invalidDomainCount" -ne 0 ]; then
  writePlainTextLog "${invalidDomainCount} invalid host(s) were supplied for updating" "warn" "warn" "ddns"
fi
if [ "$failedHostCount" -ne 0 ]; then
  writePlainTextLog \
    "${failedHostCount} host update(s) failed; review 'CF-ERR:' lines in this log to help determine what may have gone wrong" "err" "fail" "ddns" 26
  exit 26
else
  writePlainTextLog "${scriptName} completed successfully" "info" "ok" "script"
fi

### exit return codes
# 0: normal exit, no errors
# 1: invalid or unknown parameter
# 2: cannot find or access required external program(s)
# 3: curl error (probably connection)
# 10: cannot auto-detect IP address
# 21: accountFile has a null or missing cfKey variable
# 22: accountFile has a null or missing cfZoneId variable
# 25: Cloudflare API error
# 26: one or more updates failed
# 99: unspecified error occurred