Free communication protocol software for linux

Meldware Communication Suite is a platform independent groupware package consisting of:
Meldware Mail
Meldware Calendar
Meldware Webmail
Meldware Secure Administration System
Together the package provides support for thousands of users to concurrently send and receive email and schedule meetings. MCS uniquely allows you to store all messages and scheduling events in nearly any database and runs on nearly all popular software and hardware platforms.
Additionally, while the scheduling and calendaring services are able to be installed separately, the integrated featureset provides both a unique and powerful experience to both users and server-side Mail Based Applications and Collaboration Based Application Services.
The MCS platform provides security integration using LDAP sources including Microsoft Active Directory as well as flat-file and Database sources. Additionally, extensible security allows custom authentication/authorization sources.
Enhancements:
- IMAP is now stable with Mozilla Thunderbird and POP/SMTP are production ready.
- New Filestore code was implemented and many improvements were made in mailbox and storage code.

Inter-Thread Communication (ITC) aims to make it exceedingly easy to call functions in other threads.
The lexer does all the work, so just run the lexer on your headers, then call the stub functions.
In addition, it also provides a complete threading API, with the four threading primitives and a high speed threadsafe FIFO class.
Enhancements:
- It add support for GCC 4.x, and the build system is fixed.

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.

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.

Libtubo Interprocess Communication is a small and simple library that can run processes in the background and communicate via the stdout, stderr, and stdin file descriptors.
The functionality of libtubo is similar to the glib function g_spawn_async_with_pipes(), except that all pipe setup and monitoring is taken care of.
The calling function only has to provide the functions with which to process the input/output of the remote process.
The library first appeared in the year 2000 in the xfce3 desktop as part of the xfsamba application, and is now available for use for other developers.
Enhancements:
- Some control bugfixes.
- The version has been updated to the xffm scheme, as this package is now distributed with xffm.

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.

Crossfire::Protocol::Base is a client protocol module.

SYNOPSIS

use base Crossfire::Protocol::Base; # you have to subclass

Base class to implement a crossfire client.
new Crossfire::Protocol::Base host => ..., port => ...

METHODS THAT CAN/MUST BE OVERWRITTEN

$self->setup ($setup)

Called after the last setup packet has been received, just before an addme request is sent.

$self->addme_success

$self->addme_failure

$self->eof

$conn->anim_update ($num) [OVERWRITE]

$conn->sound_play ($x, $y, $soundnum, $type)

$conn->query ($flags, $prompt)

$conn->drawextinfo ($color, $type, $subtype, $message)

$conn->drawinfo ($color, $text)

$conn->player_update ($player)

tag, weight, face, name

$conn->stats_update ($stats)

$conn->container_add ($id, $item...)

$conn->container_clear ($id)

$conn->item_update ($item)

$conn->item_delete ($item...)

$conn->spell_add ($spell)

$spell = {
tag => ...,
level => ...,
casting_time => ...,
mana => ...,
grace => ...,
damage => ...,
skill => ...,
path => ...,
face => ...,
name => ...,
message => ...,
};

$conn->spell_update ($spell)

(the default implementation calls delete then add)

$conn->spell_delete ($spell)

$conn->magicmap ($w, $h, $px, $py, $data)

$conn->map_change ($type, ...)

$conn->image_info ($numfaces, $chksum, [...image-sets])

$conn->map_change ($mode, ...) [OVERWRITE]

current < flags > < x > < y > < width > < height > < hashstring >

$conn->map_clear [OVERWRITE]

Called whenever the map is to be erased completely.

$conn->map_update ([ [x,y], [x,y], ...]) [OVERWRITE]

Called with a list of x|y coordinate pairs (as arrayrefs) for cells that have been updated and need refreshing.

$conn->map_scroll ($dx, $dy) [OVERWRITE]

Called whenever the map has been scrolled.

$conn->face_update ($facenum, $facedata, $changed) [OVERWRITE]

Called with the face number of face structure whenever a face image becomes known (either because face_find returned it, in which case $changed is false, or because we got an update, in which case $changed is true).

$conn->face_find ($facenum, $facedata) [OVERWRITE]

Find and return the png image for the given face, or the empty list if no face could be found, in which case it will be requested from the server.

$conn->send ($data)

Send a single packet/line to the server.

$conn->send_command ($command[, $cb1[, $cb2]])

Uses either command or ncom to send a user-level command to the server. Encodes the command to UTF-8.

If the server supports a fixed version of the ncom command and this is detected by this module, the following is also supported:

If the callback $cb1 is given, calls it with the absolute time when this command has finished processing, as soon as this information is available.

If the callback $cb2 is given it will be called when the command has finished processing, to the best knowledge of this module.