picotorrent/bittorrent_constants.py at master · lupinthird/picotorrent · GitHub

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"""BitTorrent assigned numbers from BEP 0004.

Source: docs/bep_0004.rst_post.html
"""

from __future__ import annotations

from enum import IntEnum


PROTOCOL_STR = b"BitTorrent protocol"
PROTOCOL_STR_LEN = len(PROTOCOL_STR)  # 19
HANDSHAKE_RESERVED_BYTES = 8


class CoreMessageID(IntEnum):
    """Core BitTorrent wire protocol message IDs."""

    CHOKE = 0x00
    UNCHOKE = 0x01
    INTERESTED = 0x02
    NOT_INTERESTED = 0x03
    HAVE = 0x04
    BITFIELD = 0x05
    REQUEST = 0x06
    PIECE = 0x07
    CANCEL = 0x08


class DHTMessageID(IntEnum):
    """DHT extension message IDs."""

    PORT = 0x09


class FastExtensionMessageID(IntEnum):
    """Fast extension message IDs."""

    SUGGEST = 0x0D
    HAVE_ALL = 0x0E
    HAVE_NONE = 0x0F
    REJECT_REQUEST = 0x10
    ALLOWED_FAST = 0x11


class AdditionalDeployedMessageID(IntEnum):
    """Additional IDs used in deployed clients."""

    LTEP_HANDSHAKE = 0x14


class HashTransferMessageID(IntEnum):
    """Hash transfer protocol message IDs."""

    HASH_REQUEST = 0x15
    HASHES = 0x16
    HASH_REJECT = 0x17


# Reserved handshake capability bits from BEP 0004.
# Format: RESERVED_BITS[byte_index][bit_mask] = description
RESERVED_BITS: dict[int, dict[int, str]] = {
    0: {
        0x80: "Azureus Messaging Protocol",
    },
    2: {
        0x08: "BitTorrent Location-aware Protocol (no known implementations)",
    },
    5: {
        0x10: "LTEP (Libtorrent Extension Protocol)",
        0x02: "Extension Negotiation Protocol",
        0x01: "Extension Negotiation Protocol",
    },
    7: {
        0x01: "BitTorrent DHT",
        0x02: "XBT Peer Exchange",
        0x04: "Fast extensions (suggest/haveall/havenone/reject/allowed fast)",
        0x08: "NAT Traversal",
        0x10: "Hybrid torrent legacy to v2 upgrade",
    },
}


# Known collisions listed in BEP 0004.
RESERVED_BIT_COLLISIONS: dict[int, dict[int, str]] = {
    0: {0xFF: "BitComet Extension Protocol"},
    1: {0xFF: "BitComet Extension Protocol"},
    7: {0x01: "XBT Metadata Exchange (XBT only)"},
}


ALL_MESSAGE_IDS: dict[int, str] = {
    **{int(v): v.name.lower() for v in CoreMessageID},
    **{int(v): f"dht_{v.name.lower()}" for v in DHTMessageID},
    **{int(v): f"fast_{v.name.lower()}" for v in FastExtensionMessageID},
    **{int(v): f"deployed_{v.name.lower()}" for v in AdditionalDeployedMessageID},
    **{int(v): f"hash_{v.name.lower()}" for v in HashTransferMessageID},
}