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Net-BitTorrent-v2.0.0
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/ Net::BitTorrent::Protocol::BEP03

NAME

Net::BitTorrent::Protocol::BEP03 - Core BitTorrent Peer Wire Protocol

SYNOPSIS

use Net::BitTorrent::Protocol::BEP03;

my $proto = Net::BitTorrent::Protocol::BEP03->new(
    infohash => $ih,
    peer_id  => $id
);

# Generate initial handshake
my $out = $proto->write_buffer( );

# Process incoming bytes from the socket
$proto->receive_data( $raw_bytes );

# Send a custom message
$proto->send_message( 4, pack('N', $piece_index) ); # HAVE

DESCRIPTION

Net::BitTorrent::Protocol::BEP03 implements the foundational BitTorrent Peer Wire Protocol (BEP 03). It is a stateful, loop-agnostic parser and generator for the binary messages exchanged between peers over TCP (or uTP).

This module handles the initial handshake, reserved bit negotiation, and the framing of all standard messages (choke, unchoke, interested, have, bitfield, request, piece, etc.).

METHODS

new( %params )

Creates a new BEP03 protocol handler.

Expected parameters:

infohash

The 20 or 32-byte binary infohash.

peer_id

The local 20-byte binary peer ID.

reserved - optional

The 8-byte reserved bits string.

send_handshake( )

Sends the initial protocol handshake.

$proto->send_handshake();

receive_data( $data )

Feeds raw data into the protocol parser.

$proto->receive_data( $chunk );

Expected parameters:

$data

The binary data received from the transport.

write_buffer( )

Returns pending messages from the output buffer.

my $out = $proto->write_buffer();

send_message( $id, [$payload] )

Queues a protocol message.

$proto->send_message( 4, pack('N', 42) ); # HAVE piece 42

Expected parameters:

$id

The numeric message ID.

$payload - optional

The raw binary payload.

send_keepalive( )

Queues a keep-alive message.

$proto->send_keepalive();

send_choke( )

Sends a CHOKE message.

send_unchoke( )

Sends an UNCHOKE message.

send_interested( )

Sends an INTERESTED message.

send_not_interested( )

Sends a NOT_INTERESTED message.

send_have( $index )

Sends a HAVE message.

Expected parameters:

$index

The piece index.

send_bitfield( $data )

Sends a BITFIELD message.

Expected parameters:

$data

The binary bitfield data.

set_reserved_bit( $byte, $mask )

Sets a bit in the reserved bytes of the handshake.

$proto->set_reserved_bit( 5, 0x10 );

Expected parameters:

$byte

The byte index (0-7).

$mask

The bitmask to apply.

handshake event

Emitted when a handshake is successfully received.

$proto->on( handshake => sub ( $self, $ih, $id ) { ... } );

Expected parameters:

$ih

The 20 or 32-byte binary infohash.

$id

The 20-byte binary peer ID.

peer_id( )

Returns the local peer ID.

reserved( )

Returns or sets the reserved bytes string.

Expected parameters:

$val - optional

The new 8-byte reserved string.

state( )

Returns the current protocol state ('HANDSHAKE', 'OPEN', or 'CLOSED').

detected_ih( )

Returns the infohash detected during the handshake (useful for trackers/servers).

AUTHOR

Sanko Robinson <sanko@cpan.org>

COPYRIGHT

Copyright (C) 2008-2026 by Sanko Robinson.

This library is free software; you can redistribute it and/or modify it under the terms of the Artistic License 2.0.