/tomato-ddns

A awful implementation of DDNS to be used in a tomato router for DNS dynamic registry on a LAN.

Primary LanguagePHP

tomato-ddns

A awful implementation of DDNS to be used in a tomato router for dynamic DNS registration on a LAN.

Inspired by: https://yingtongli.me/blog/2017/04/18/dynamic-dns.html

The problem:

I tried:

Manual insertion of DNS registries but well... breaks the automation. Same for hosts files as well.

zeroconf/avahi/bonjour:

  • Works only for FQDN ( hostname.local ) due a secure limitation on avahi implementation for linux so hostnames are not solved.
  • Containers don't recognise the .local unless the necessary dependencies are present within.

Record all pool of IPs used in advance:

  • Set records in advance it's an viable solution when you knows the names in advance. I'm using Rancher with a vmware node driver where the vms are dinamically provisioned and the hostnames are not predictable.

Implementation:

Tomato by default uses a setting to extend the hosts into the /etc/dnsmasq/hosts directory: the "addn-hosts=/etc/dnsmasq/hosts" where tomato store a hosts file. Every file created inside this directory will be treated as a aditional hosts file.

  1. In order to create a DNS entry a simple curl can be used trigger the process:
curl  "http://192.168.1.1:8080/dns.php?ip=192.168.1.224&fqdn=playstation4.home"

Parameters:

  • ip=192.168.1.224
  • fqdn=playstation4.home

or:

curl  "http://192.168.1.1:8080/dns.php?ip=192.168.1.224&hostname=playstation4&fqdn=playstation4.home"

Parameters:

  • ip=192.168.1.224
  • hostname=playstation4
  • fqdn=playstation4.home

image

  1. The dns.php reads the parameters and write as a hosts file inside /etc/dnsmasq/hosts directory. Another file called reload.dnsmasq is also created in order to trigger the reload of dnsmasq daemon and read the new entry.

  2. A schedulled job is set on tomato to run the reload: When the file reload.dnsmasq is found the dnsmasq is reloaded and erased.

if [ -e "/tmp/reload.dnsmasq" ]; then
        rm -rf /tmp/etc/dnsmasq/hosts/*.*
        cp /jffs/www/dhosts/* /tmp/etc/dnsmasq/hosts/
        service dnsmasq restart
        rm -rf /tmp/reload.dnsmasq
fi

image

  1. The new host and fqdn will be working in the host using the tomato as a DNS server.

TO-DO

  • Integrate on Advanced Tomato
  • Implement a server side IP/scope/netmask restriction
  • Implement a server side domain restriction

KNOWN BUGS

  • Create a check to the delete the old entry when the old name is reused. ( I'm manually handling that for now )
  • Persistance using a external storage ( I'm managing for the moment by using JFFS - CAUTION WEARS OUT THE INTERNAL FLASH STORAGE )