README

Barev Pascal Library

A FreePascal implementation of the Barev protocol - a simplified peer-to-peer XMPP protocol for Yggdrasil IPv6 networks.

Overview

Barev enables direct messaging between nodes on Yggdrasil networks without central servers, using a "one pipe per buddy" connection model.

• JID Format: localpart@yggdrasil_ipv6_address
• Port: 1377 (default, configurable)
• Protocol: TCP over IPv6 (Yggdrasil addresses only)
• Security: Provided by Yggdrasil network encryption

Project Structure

barevtypes.pas  - Basic types, constants, and data structures
barevxml.pas    - XML generation and parsing for XMPP stanzas
barevnet.pas    - Network/socket management (IPv6)
barev.pas       - Main client interface
testbarev.pas   - Simple test/demo program

Requirements

• FreePascal 3.0.0 or later
• Linux/Unix system (uses Unix sockets API)
• Yggdrasil network connection with IPv6 address

Building

Quick Build

make

This creates the testbarev executable.

Manual Build

fpc testbarev.pas

Building Individual Units

make install-units

This compiles all units into the lib/ directory.

Usage

Simple Example

uses
  Barev, BarevTypes;

var
  Client: TBarevClient;
  Buddy: TBarevBuddy;

begin
  // Create client with your nick and Yggdrasil IPv6
  Client := TBarevClient.Create('mynick', '201:af82:9f2f:7809::1');

  // Set up event handlers
  Client.OnMessageReceived := @OnMessageReceived;
  Client.OnBuddyStatus := @OnBuddyStatus;
  Client.OnLog := @OnLog;

  // Start listening
  if not Client.Start then
    WriteLn('Failed to start');

  // Add a buddy
  Buddy := Client.AddBuddy('friend', '201:7a74:aa1e:101a::a1');

  // Connect to buddy
  Client.ConnectToBuddy(Buddy.JID);

  // Main loop
  while Running do
  begin
    Client.Process;  // Handle network events
    // Your application logic here
    Sleep(100);
  end;

  // Cleanup
  Client.Stop;
  Client.Free;
end.

Running the Test Program

./testbarev

The test program will prompt for:

1. Your nickname
2. Your Yggdrasil IPv6 address

Then provides an interactive command-line interface.

Test Program Commands

help                   - Show help
add <nick@ipv6>        - Add a buddy
list                   - List all buddies
connect <nick@ipv6>    - Connect to a buddy
msg <nick@ipv6> <text> - Send a message
status <status> [msg]  - Set your status (available/away/dnd)
load <file>            - Load contacts from file
save <file>            - Save contacts to file
quit                   - Exit

Contact List File Format

Create a text file (e.g., contacts.txt):

# Barev Contacts
# Format: nick@ipv6_address or nick@ipv6_address:port

alice@201:af82:9f2f:7809:be0c:360a:1587:6be7
bob@201:7a74:aa1e:101a::a1:5299
charlie@202:baad:cafe:1234::1

Then load it:

> load contacts.txt

API Reference

TBarevClient

Main client class for Barev messaging.

Constructor

constructor Create(const ANick, AMyIPv6: string; APort: Word = BAREV_DEFAULT_PORT);

Methods

Client Control

• Start: Boolean - Start the client and begin listening
• Stop - Stop the client
• Process - Process network events (call regularly in your main loop)

Buddy Management

• AddBuddy(Nick, IPv6: string; Port: Word): TBarevBuddy - Add a buddy
• RemoveBuddy(JID: string): Boolean - Remove a buddy
• GetBuddy(JID: string): TBarevBuddy - Find buddy by JID
• GetBuddyCount: Integer - Get number of buddies
• GetBuddyByIndex(Index: Integer): TBarevBuddy - Get buddy by index

Contact List

• LoadContactsFromFile(FileName: string): Boolean - Load contacts
• SaveContactsToFile(FileName: string): Boolean - Save contacts

Communication

• ConnectToBuddy(JID: string): Boolean - Initiate connection to buddy
• SendMessage(JID, Text: string): Boolean - Send a message
• SendPresence(Status: TBuddyStatus; Message: string): Boolean - Broadcast presence
• SendPresenceToBuddy(JID: string; Status: TBuddyStatus; Message: string): Boolean - Send presence to specific buddy

Event Handlers

property OnBuddyStatus: TBuddyStatusEvent;
  // Called when buddy status changes
  // procedure(Buddy: TBarevBuddy; OldStatus, NewStatus: TBuddyStatus)

property OnMessageReceived: TMessageReceivedEvent;
  // Called when message is received
  // procedure(Buddy: TBarevBuddy; const MessageText: string)

property OnConnectionState: TConnectionStateEvent;
  // Called when connection state changes
  // procedure(Buddy: TBarevBuddy; State: TConnectionState)

property OnLog: TLogEvent;
  // Called for log messages
  // procedure(const LogLevel, Message: string)

TBarevBuddy

Represents a contact/buddy.

Properties

• Nick: string - Buddy's nickname
• IPv6Address: string - Buddy's Yggdrasil IPv6 address
• Port: Word - Buddy's port number
• JID: string - Full JID (nick@ipv6)
• Status: TBuddyStatus - Current status
• StatusMessage: string - Status message

Types

TBuddyStatus

bsOffline
bsAvailable
bsAway
bsExtendedAway
bsDoNotDisturb

TConnectionState

csDisconnected
csConnecting
csStreamInit
csAuthenticated
csOnline

Testing Two Clients

Terminal 1:

./testbarev
Enter your nick: alice
Enter your Yggdrasil IPv6: 201:af82:9f2f:7809::1

> add bob@201:7a74:aa1e:101a::a1
> connect bob@201:7a74:aa1e:101a::a1

Terminal 2:

./testbarev
Enter your nick: bob
Enter your Yggdrasil IPv6: 201:7a74:aa1e:101a::a1

> add alice@201:af82:9f2f:7809::1
# Alice's connection should be accepted automatically

Send Messages:

# In Terminal 1:
> msg bob@201:7a74:aa1e:101a::a1 Hello Bob!

# In Terminal 2:
*** Message from alice: Hello Bob!
> msg alice@201:af82:9f2f:7809::1 Hi Alice!

Protocol Details

Connection Model

• Each buddy pair maintains exactly ONE active TCP connection
• First connection established wins
• All bidirectional communication flows through this single pipe
• Subsequent connections from the same buddy replace the existing connection

Stream Flow

1. Initiator sends stream header:

<?xml version="1.0" encoding="UTF-8" ?>
<stream:stream xmlns="jabber:client" xmlns:stream="http://etherx.jabber.org/streams" from="you@your_ip" to="buddy@buddy_ip">

2. Receiver responds with their stream header:

<?xml version="1.0" encoding="UTF-8" ?>
<stream:stream xmlns="jabber:client" xmlns:stream="http://etherx.jabber.org/streams" from="buddy@buddy_ip" to="you@your_ip">

3. Both exchange presence:

<presence/>

4. Chat communication begins

Message Format

<message to="buddy@buddy_ip" type="chat">
  <body>Hello world!</body>
</message>

Keepalive (Ping/Pong)

The library automatically sends pings every 30 seconds and marks buddies offline after 3 consecutive failures.

Limitations & TODO

Current Limitations:

• No file transfer support (XEP-0096/XEP-0065 not implemented)
• No VCard support
• Simple XML parser (not full XMPP compliance)
• Unix/Linux only (socket API)
• No TLS (relies on Yggdrasil encryption)

Future Enhancements:

• File transfer support
• VCard/avatar support
• Better XML parsing (full DOM or SAX)
• Windows socket support
• Threading for better concurrency
• Logging levels
• Configuration file support
• Message history

Troubleshooting

"Failed to bind to port 5299"

• Port might already be in use
• Try a different port: Client := TBarevClient.Create('nick', 'ipv6', 5300);
• Check with: netstat -tuln | grep 5299

"Connection refused"

• Buddy is not listening (not running Barev client)
• Wrong IPv6 address
• Firewall blocking port 5299
• Test connectivity: ping6 <buddy_ipv6>

"Failed to connect: address resolution failed"

• Invalid IPv6 address format
• Not a Yggdrasil address (must start with 200-3ff)

"Connection from unknown IP"

• Buddy not in your contact list
• Add them first: add <nick@ipv6>

Contributing

This is an initial implementation. Improvements welcome!

Key areas for contribution:

• Windows support
• Better threading/async I/O
• Full XMPP compliance
• File transfer support
• Unit tests

License

GPL v2 or later (matching original Pidgin Bonjour plugin)

Credits

Based on the Pidgin Bonjour plugin, modified for Yggdrasil networks. Protocol specification: barev.md

References

• Barev Protocol: https://github.com/norayr/barev
• Yggdrasil Network: https://yggdrasil-network.github.io/
• XMPP Core: RFC 6120
• Pidgin: https://pidgin.im/