dhcpd.leases dashboard

I was looking for a simple way to monitor the dhcpd(8) leases, subnet utilization and generally the state of the OpenBSD dhcpd server but I couldn't find any tool suitable for my needs. Most options are an overkill for small networks and small routers like the APU, ODROID, Protectli etc.

Dhcpd-leasesd is a simple dashboard for the dhcpd.leases file of the OpenBSD dhcpd server that is very easy to install and use.
Basically all this dashboard does is present the data in dhcpd.leases plus some data from dhcpd.conf (subnets, ranges and fixed addresses) in a user friendly way including full dynamic searching, filtering and sorting. It can easily handle a few class C subnets or more, depending on your HW.

• Pure sh script. Runs on a base OpenBSD installation with no dependancies.
• Javascript and styles can be merged into the script to create a single file server or cgi script that is easy to deploy. This is the preferred way of using this script.
• Can optionally do MAC address Vendor lookup using the standards-oui.ieee.org data. Please note that Vendor lookup adds to the processing time.
• Displays IPs from both the dhcpd IP pool and fixed addresses (IP reservations).
• Filtering, sorting and searching in the browser.
• Requires read access to /var/db/dhcpd.leases and /etc/dhcpd.conf files.
• Can be started from rc.local

Safari on macOS

Firefox on OpenBSD

Iridium (Chromium) on OpenBSD

Installation

Starting with V1.5 the merged version of the script (single file server) will be available in the releases. Just download that, gunzip it and move it to /usr/local/sbin/ or to somewhere in your $PATH and you are done.

  $ gunzip dhcpd-leasesd.gz
  $ chmod +x dhcpd-leasesd.sh
  $ mv dhcpd-leasesd.sh /usr/local/sbin/

You can still use the unmerged files if you want to:

$ git clone https://github.com/facelessfish/dhcpd-leasesd (or Code/Download zip
and unzip)
$ cd dhcpd-leasesd
$ chmod +x dhcpd-leasesd
$ ./dhcpd-leasesd -dv -l <ip address to listen>

To generate and install the single file server:

$ ./dhcpd-leasesd -f dhcpd-leasesd.sh
$ mv dhcpd-leasesd.sh /usr/local/sbin/

Running

$ dhcpd-leasesd.sh -dv -l <ip address to listen>

On first run (or after a reboot or after /tmp is cleared by the system) it will download the OUI data and cache it in /tmp if -v is specified. Wait for the download to finish and then visit: http://<ip address>:9130 with a fairly recent browser.
Tested in Safari, Firefox and Chromium.

Upgrade

Overwrite the old version of the script with the new one and run dhcpd-leasesd.sh -k to kill it, if it's running in the background. Then start dhcpd-leasesd.sh with the same parameters as the old version.

The dashboard can be served in 2 (+1) ways.

• Using the builtin nc(1) "HTTP server".
  This the easiest way to run the dashboard. Please note that it has a serious limitation of only 1 concurrent request (server is unavailable during processing).
  ex.

  $ dhcpd-leasesd -dv -l 192.168.0.1
  

  to start it in the background:

  $ dhcpd-leasesd -dv -l 192.168.0.1 &
  

• Using tcpserver(1).
  This option requires the ucspi-tcp package which contains the tcpsrver. Most flexible option due to the tcpserver configuration options. Can easily handle any number of concurrent requests.
  ex.

  $ tcpserver 192.168.0.1 9130 dhcpd-leasesd.sh -tv
  

• As a slowcgi(8) script for httpd(8).
  it is possible to partially run the script as a cgi but it currently lacks vendor lookup support and it's likely more trouble than it's worth. Vendor lookup depends on nc(1) and running it in the httpd(8) chroot looks messy. I'll look into it at some point.

  Copy the following commands to the chroot

  $ cp /bin/date /var/www/bin/
  $ cp /bin/cat /var/www/bin/
  $ cp /bin/sh /var/www/bin/
  

  then copy the config and leases files to the chroot (create the folders if they dont exist)

  $ cp /etc/dhcpd.conf /var/www/etc/
  $ cp /var/db/dhcpd.leases /var/www/var/db/
  

  and then copy the merged script to /var/www/cgi-bin/dhcpd-leasesd.sh

  Finally edit your server in /etc/httpd.conf to include something like:

   location "/cgi-bin/*" {
      fastcgi socket "/run/slowcgi.sock"
      root "/"
  }
  

  Start the httpd(8) and the slowcgi(8) servers and visit http://<your_server>/cgi-bin/dhcpd-leasesd.sh. You can use httpd -dvvv, slowcgi -dv and /tmp/dhcpd_leases.log to debug if you need to.

  After it's running you can set up cron(8) to periodically update /var/www/etc/dhcp.conf and /var/www/var/db/dhcpd.leases.

Usage

dhcpd-leasesd [-b dhcpd.leases] [-c dhcpd.conf] [-t] [-v] [-u] [-f out_file] 
              [-d [-l listening_ip_address] [-p port]] 

Run without options will output HTML on stdout and exit.

-d Run as a deamon using the nc http server. Can only serve one request at a 
   time. -t is ignored (always on).

-l Listening address. Used only with -d. Default: 127.0.0.1

-p Listening port. Used only with -d. Default: 9130

-v Enable MAC address vendor lookup. Oui db will be downloaded and cached into
   /tmp if not already cached.

-t Prepend an HTTP 200 header to the HTML output. Needed when used with 
   tcpserver.

-b Path to dhcps.leases. Default: /var/db/dhcpd.leases

-c Path to dhcpd.conf. Default: /etc/dhcpd.conf

-u Update the vendor database and exit. All other options are ignored.

-f Merge the sh script, javascript and styles into out_file and exit. All other
   options are ignored.

-k kill the script if running in the background and exit.

Examples:
  $ dhcpd-leasesd.sh -d

  $ dhcpd-leasesd.sh -dv -b ./dhcpd.leases -c ./dhcpd.conf -l 192.168.0.1 -p 9130

  $ dhcpd-leasesd -f dhcpd-leasesd.sh 

  $ tcpserver 192.168.0.1 9130 dhcpd-leasesd.sh -tv

Changelog

V1.5

• Added support for Fixed IP addresses
• Added logging to /tmp/dhcpd_leases.log if running in the background
• Running as an httpd(8) cgi is somewhat supported but lacks Vendor Lookup
• Updated Readme

V1.4

• graph: alternate color of hour labels (per day).
• added option -k to kill the script if its running in the background. Makes it easy to upgrade.
• fixed wheel scroll event (mousewheel is deprecated)

V1.3

• fixed a bug where the first bar of the bargraph would not show
• improved handling of renewed leases
• More code cleanup & bug fixes

v1.2

• Better handling of background OUI db download.
• UI improvements and code cleanup.
• Visually indicate renewed active leases.
• Starts fine from rc.local (diabled text output if not run from a terminal)