bash - sysadm - /usr/sbin/ddns-update

ddns-update

#!/bin/bash -eu

#######################################################################
##                                                                   ##
## A simple, lightweight and self contained alternative to ddclient. ##
##                                                                   ##
#######################################################################

#
# Configuration
# -------------
#
# Create a configuration file at: /etc/ddns/update.conf
# For example:
#
#     he.password=secret
#     he.iface=wlo1,inet,global,laptop.example.com
#     he.iface=eth0,all,global,laptop-wired.example.com
#     he.iface=eth1,inet6,link,laptop.local.example.com,another-password,another-login
#     he.ipv4-prefix=ipv4-
#     he.ipv6-prefix=
#
#     cloudflare.login=1234zoneid1234cafebabe1234cafebabe
#     cloudflare.password=secred
#     cloudflare.iface=eth1,inet6,link,workstation.example.com
#
# which means:
#
# 1. provider "he" means: Hurricane Electric.
# 2. define a default password for updating DDNS records;
# 3. update record laptop.example.com from IPv4 global scoped address from interface wlo1;
# 4. update record laptop.example.com from IPv4 and IPv6 global scoped addresses from interface eth0;
# 5. update record laptop.local.example.com from IPv6 link scoped address from interface eth1, employing a distinct password and a distinct login.
# 6. An IPv4 prefix "ipv4-" will be prepended to the fqdn when an IPv4 address is updated.
# 7. An IPv6 prefix "" (i.e.: nothing in this example) will be prepended to the fqdn when an IPv6 address is updated.
#
# List of supported providers:
#   * he for Hurricane Electric
#   * cloudflare
#
# What if you do not pass any information at all, except the password (and login, if required)?
#
# It will grab the first interface which is UP, if any, assume all protocols, global scope and your FQDN.
#
#
# Installation
# ------------
#
# 1. Copy this script onto /usr/sbin/ddns-update
# 2. Remember to make it executable
# 3. Create an entry on /etc/crontab like this:
#
#     0,5,10,15,20,25,30,35,40,45,50,55 * * * * /usr/sbin/ddns-update
#


function ddns_update_he {
  local iface=$1
  local proto=$2
  local scope=$3
  local fqdn=$4
  local password=$5
  local login=$6

  if [[ ! -z "$(ip link show dev ${iface} | head -1 | fgrep 'state UP')" ]] ;then
    local myip=$(ip -${proto} address show dev ${iface} | fgrep "scope ${scope}" | head -1 | sed -r 's/[ \t]+/ /g' | cut -d' ' -f3 | cut -d/ -f1)
    if [ ! -z "${myip}" ] ;then
      echo /usr/bin/curl -${proto} -s "https://dyn.dns.he.net/nic/update" -d "myip=${myip}" -d "hostname=${fqdn}" -d "password=[HIDDEN]"
           /usr/bin/curl -${proto} -s "https://dyn.dns.he.net/nic/update" -d "myip=${myip}" -d "hostname=${fqdn}" -d "password=${password}"
      echo ""
    else
      echo "ERROR: provider he could not find IPv${proto} address for interface ${iface}"
    fi
  fi
}


function ddns_update_cloudflare {
  local iface=$1
  local proto=$2
  local scope=$3
  local fqdn=$4
  local password=$5
  local login=$6

  case "${proto}" in
    6) local type=AAAA;;
    *) local type=A;
  esac

  if [[ ! -z "$(ip link show dev ${iface} | head -1 | fgrep 'state UP')" ]] ;then
    local myip=$(ip -${proto} address show dev ${iface} | fgrep "scope ${scope}" | head -1 | sed -r 's/[ \t]+/ /g' | cut -d' ' -f3 | cut -d/ -f1)
    if [ ! -z "${myip}" ] ;then
      local id=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/${login}/dns_records?type=${type}&name=${fqdn}" \
                      -H "Authorization: Bearer ${password}" \
                      -H "Content-Type: application/json" | \
                 tr -d '"' | \
                 grep -Eo '\{id:([0-9a-f]+)' | \
                 cut -d: -f2)

      if [ -z ${id} ] ;then
        curl -s -X POST "https://api.cloudflare.com/client/v4/zones/${login}/dns_records" \
             -H "Authorization: Bearer ${password}" \
             -H "Content-Type: application/json" \
             --data "{\"type\":\"${type}\",\"name\":\"${fqdn}\",\"content\":\"${myip}\",\"ttl\":3600,\"priority\":10,\"proxied\":false}"
      else
        curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/${login}/dns_records/${id}" \
             -H "Authorization: Bearer ${password}" \
             -H "Content-Type: application/json" \
             --data "{\"type\":\"${type}\",\"content\":\"${myip}\"}"
      fi
    else
      echo "ERROR: provider cloudflare could not find IPv${proto} address for interface ${iface}"
    fi
  fi
}


function ddns_update {
  local provider=${1}
  if [[ -f /etc/ddns-update.conf ]] ; then
    local username=$(cat /etc/ddns-update.conf | fgrep ${provider}. | fgrep login=    | cut -d= -f2)
    local password=$(cat /etc/ddns-update.conf | fgrep ${provider}. | fgrep password=    | cut -d= -f2)
    local ipv4prefix=$(cat /etc/ddns-update.conf | fgrep ${provider}. | fgrep ipv4-prefix= | cut -d= -f2)
    local ipv6prefix=$(cat /etc/ddns-update.conf | fgrep ${provider}. | fgrep ipv6-prefix= | cut -d= -f2)
    local hostname=$(hostname --fqdn)
    if [[ $(cat /etc/ddns-update.conf | fgrep ${provider}. | fgrep iface= | grep -v -E '^#' | wc -l) != 0 ]] ;then
      cat /etc/ddns-update.conf | fgrep ${provider}. | fgrep iface= | grep -v -E '^#' | while read line ;do
        local  args=$(echo "${line}"  | cut -s -d= -f2)
        # obtain parameters
        local iface=$(echo "${args}" | cut    -d, -f1)
        local proto=$(echo "${args}" | cut -s -d, -f2)
        local scope=$(echo "${args}" | cut -s -d, -f3)
        local  fqdn=$(echo "${args}" | cut -s -d, -f4)
        local  pass=$(echo "${args}" | cut -s -d, -f5)
        local login=$(echo "${args}" | cut -s -d, -f6)
        # assume defaults
        local proto=${proto:-all}
        local scope=${scope:-global}
        local  fqdn=${fqdn:-${hostname}}
        local  pass=${pass:-${password}}
        local login=${login:-${username}}
        #  handle protocol
        if [[ "${proto}" == "all" ]] ;then
          ddns_update_${provider} ${iface} 4 ${scope} ${ipv4prefix}${fqdn} ${pass} ${login}
          ddns_update_${provider} ${iface} 6 ${scope} ${ipv6prefix}${fqdn} ${pass} ${login}
        elif [[ "${proto}" == "inet" ]] ;then
          ddns_update_${provider} ${iface} 4 ${scope} ${ipv4prefix}${fqdn} ${pass} ${login}
        elif [[ "${proto}" == "inet6" ]] ;then
          ddns_update_${provider} ${iface} 6 ${scope} ${ipv6prefix}${fqdn} ${pass} ${login}
        else
          echo "ERROR: unknown protocol ${proto}"
        fi
      done
    else
      local iface=$(ip link | fgrep 'state UP' | head -1 | cut -d' ' -f2 | cut -d: -f1)
      if [[ ! -z "${iface}" ]] ;then
        local scope=${scope:-global}
        local  fqdn=${fqdn:-${hostname}}
        local  pass=${pass:-${password}}
        local login=${pass:-${username}}
        ddns_update_${provider} ${iface} 4 ${scope} ${ipv4prefix}${fqdn} ${pass} ${login}
        ddns_update_${provider} ${iface} 6 ${scope} ${ipv6prefix}${fqdn} ${pass} ${login}
      fi
    fi
  fi
}


# see: https://www.urbanautomaton.com/blog/2014/09/09/redirecting-bash-script-output-to-syslog/
exec 1> >(logger -s -t $(basename $0)) 2>&1

ddns_update he
ddns_update cloudflare

Create configuration file /etc/ddns-update.conf like the example below:

he.password=my_password_for_ddns_updates_on_hurricane_electric

cloudflare.login=123cafebabe123cafebabe123cafebabe
cloudflare.password=MyTokenForEditingThisZoneOnCloudflare
cloudflare.iface=ens3,inet6,link,subdomain.example.com

Create entry on /etc/crontab

$ echo "0,5,10,15,20,25,30,35,40,45,50,55 * * * * /usr/sbin/ddns-update" | sudo tee -a /etc/crontab