distributed.camp
A Python port of the Invisible Internet Project (I2P)
1"""Tunnel data types — TunnelId, HopConfig, TunnelInfo."""
2
3import struct
4import time
5
6
7class TunnelId:
8 """4-byte unsigned integer tunnel identifier."""
9
10 def __init__(self, tunnel_id: int):
11 if tunnel_id < 0 or tunnel_id >= 2**32:
12 raise ValueError(f"TunnelId must be 0..2^32-1, got {tunnel_id}")
13 self._id = tunnel_id
14
15 def to_bytes(self) -> bytes:
16 return struct.pack("!I", self._id)
17
18 @classmethod
19 def from_bytes(cls, data: bytes) -> "TunnelId":
20 if len(data) < 4:
21 raise ValueError(f"TunnelId requires 4 bytes, got {len(data)}")
22 return cls(struct.unpack("!I", data[:4])[0])
23
24 @classmethod
25 def from_stream(cls, stream) -> "TunnelId":
26 data = stream.read(4)
27 if len(data) < 4:
28 raise ValueError("TunnelId requires 4 bytes")
29 return cls.from_bytes(data)
30
31 def is_zero(self) -> bool:
32 return self._id == 0
33
34 def __int__(self) -> int:
35 return self._id
36
37 def __eq__(self, other) -> bool:
38 if not isinstance(other, TunnelId):
39 return NotImplemented
40 return self._id == other._id
41
42 def __hash__(self) -> int:
43 return hash(self._id)
44
45 def __repr__(self) -> str:
46 return f"TunnelId({self._id})"
47
48
49class HopConfig:
50 """Configuration for one hop in a tunnel."""
51
52 def __init__(self, receive_tunnel_id: TunnelId, send_tunnel_id: TunnelId,
53 receive_key: bytes, send_key: bytes, iv_key: bytes,
54 reply_key: bytes, reply_iv: bytes, layer_key: bytes):
55 self.receive_tunnel_id = receive_tunnel_id
56 self.send_tunnel_id = send_tunnel_id
57 self.receive_key = receive_key
58 self.send_key = send_key
59 self.iv_key = iv_key
60 self.reply_key = reply_key
61 self.reply_iv = reply_iv
62 self.layer_key = layer_key
63
64
65class TunnelInfo:
66 """Metadata about a built tunnel."""
67
68 def __init__(self, tunnel_id: TunnelId, gateway: bytes, length: int,
69 creation_time: int, expiration: int):
70 if len(gateway) != 32:
71 raise ValueError(f"Gateway hash must be 32 bytes, got {len(gateway)}")
72 self.tunnel_id = tunnel_id
73 self.gateway = gateway
74 self.length = length
75 self.creation_time = creation_time
76 self.expiration = expiration
77
78 def is_expired(self, now_ms: int | None = None) -> bool:
79 if now_ms is None:
80 now_ms = int(time.time() * 1000)
81 return now_ms >= self.expiration
82
83 def __eq__(self, other) -> bool:
84 if not isinstance(other, TunnelInfo):
85 return NotImplemented
86 return (self.tunnel_id == other.tunnel_id and
87 self.gateway == other.gateway and
88 self.length == other.length and
89 self.creation_time == other.creation_time and
90 self.expiration == other.expiration)
91
92 def __repr__(self) -> str:
93 return f"TunnelInfo(id={self.tunnel_id}, length={self.length})"