Free environmental monitoring tools and protocol software for linux

Postfix SMTP Monitoring Solution is a set of three Perl CGI scripts used to monitor the SMTP queue, allowing the deletion of messages that for one reason or another become "stuck" in the queue.

I needed a web-based solution to monitor my Postfix SMTP relay, which enabled me to remove messages that become "stuck" in the queue. I wrote three simple Perl scripts, and used Sudo to give me the desired functionality.

I am uploading these scripts in case they are useful to others. Assuming you have Apache configured correctly on your Postfix server, it should be as easy as placing the three .cgi files into your webservers cgi-bin directory, and making the appropriate modifications to your /etc/sudoers file (see the README contained in the tarball).

Digital Camera Protocol is another command-line utility for DC21x cameras, this one looks and works just like "ftp" command. Not written by me, but uses some of my low-level Kodak code from digicam.

FreeBSD ports monitoring project is a simple solution for monitoring what has changed in installed ports on a FreeBSD machine. It works quite well and shows me what is happening on some machines which are manage not only by me. And leaves some trace after handy portupgrade -a command.

But when many ports are upgraded at once output from this script becomes mess and it is hard to read what was added/removed and upgraded. Well it happens when change relates to two ports, neighbours in alphabetical sequence. Diff output with my modifiers becomes unacceptable. So I rewrote it and yes, it is now in Ruby.

Very Simple Control Protocol Daemon is a daemon for home automation tasks.
VSCP protocol is a very simple and free protocol for SOHO automation tasks & friends. The protocol is so easy that everyone can grasp the idea behind it in a few minutes.
Therefore its also very easy to construct and use VSCP aware modules and components. Nodes just start up and then serve the control solution reliable and stable for ever and ever and ever.
The protocol is free and is not designed to conquer the world and every Small Office and HOme. Very Simple Control Protocol Daemon is constructed just because its fun to make tiny little things work together.
Enhancements:
- The port was changed from 1681 to the IANA registered 9598. Scripts for Digitemp support and the first version of the ODIN database were added.

The HTTP Time Protocl (HTP) system is a set of utilities to set and maintain the system clock from the HTTP/1.1 (RFC 2616) "Date:" header. HTP requires Libconfig.
The purpose of HTP is provide a simple to use system that can be used on any system that is connected to the internet and can access atleast one web page (either directly or through a proxy) to be able to maintain an accurate clock.
HTTP Time Protocol uses basic statistical analysis to arrive at the most accurate time possible given enough servers. The more servers HTP is configured to use the more accurate the clock can be.
Enhancements:
- Cleanup/simplification of the code.
- A more robust implementation of the "-p" (precision) switch.

Host Identity Protocol on Linux is an implemetation of the Host Identity Protocol (HIP) and the related architecture. Host Identity Protocol (HIP) is a proposal to change the TCP/IP stack to securely support mobility and multi-homing.
Additionally, it provides for enhanced security and privacy and advanced network concepts, such as moving networks and mobile ad hoc networks. HIP is "cool", which means that as a mobile VPN solution, when your network interfaces go up or down, there is no need to re-establish a secure tunnel.
Enhancements:
- The implementation was moved from kernel to user space.
- Support for the Nokia 770 Linux PDA (ARM) was added.

Generic Protocol Framework aims to allow users to rapidly prototype different emerging communications protocols. Implementations can be easily "dropped in" and tested independant of a finished product. Testing on both the end product, and the protocol itself can be easily accomplished. The tool aims to provide the developer and end user with a robust solution which can track the size of messages, how rapidly they will be generated, and how many of each type can be seen.
Why the GPF:
There are many similar tools available. The problem with many of these tools is that they are 1) closed source, 2) not easily adaptable to a specific implementation (they use custom languages), 3) expensive. The advantages of the GPF are its open source nature, the ease of which it can be adapted, and the cost: free!
Basic Flow:
Modification of the GPF is fairly simple. Tool-opts.h contains the basic options that will be applied to the packet while it is being built. To transmit a packet, the system calls the tx_message() function, and passes the message ID as well as the option block. This is then passed to the custom function: tx_message_custom() in tx.c. From the message id, the system selects an appropriate tx_* function (to be implemented by the user) and passes an unsigned char **, where the buffer will be written, and the option block. In turn, that function will make heavy use of the add_buf_tu*() functions, which will allow the user to add a tubyte8, tuint16, or tuint32 number to the buffer.
In daemonize mode, the basic options are set, and the system then listens for incomming packets. When a packet arrives, the system calls basic_parse() on the packet. This function then calls basic_parse_custom(), found in parse.c. In turn, this can call any appropriate parsing helpers, including the get_tu*() functions, which allow the user to retrieve a tubyte8, tuint16, or tuint32 from the buffer. CAVEAT: if the first two bytes of the buffer are zerod, it will be treated as an END message. However, recovery is available. In the basic_parse_custom() message, you can set the end_signal_caught variable of the option_block to 0. In this case, it will not stop the daemon from running.
Enhancements:
- Currently, TCP support is somewhat experimental.
- Testing for that portion will be ongoing.
- No clear examples are provided.
- The examples/ directory contains the precursors to a MIP example.