134 lines
5.5 KiB
Python
134 lines
5.5 KiB
Python
"""Single-owner encrypted RPC session; transport cannot bypass this gate."""
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from __future__ import annotations
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import json
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import threading
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import time
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from .protocol import Handshake, ProtocolError, Reassembler
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class RpcError(Exception):
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def __init__(self, code, message):
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self.code, self.message = code, message
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super().__init__(code)
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def checked_name(value):
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if not isinstance(value, str) or not value.strip() or len(value) > 40:
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raise RpcError("BAD_REQUEST", "名称须为 1 至 40 个字符")
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if any(ord(char) < 32 or ord(char) == 127 for char in value):
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raise RpcError("BAD_REQUEST", "名称包含不支持的字符")
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return value.strip()
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class SessionManager:
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def __init__(self, dispatch, identity, *, clock=time.monotonic):
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self.dispatch = dispatch
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self.identity = identity
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self.clock = clock
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self.lock = threading.RLock()
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self.owner = None
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self.receiver = None
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self.cipher = None
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self.opened = False
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self.client_name = None
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self.last_request = -1
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self.connected_at = self.last_activity = 0
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self.generation = 0
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self.peer_mtu = 23
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def connect(self, owner):
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with self.lock:
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if self.owner is not None:
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return self.owner == owner
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self.owner = owner
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self.receiver = Reassembler(self.clock)
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self.connected_at = self.last_activity = self.clock()
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return True
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def disconnect(self, owner):
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with self.lock:
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if self.owner != owner:
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return
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self.owner = self.receiver = self.cipher = self.client_name = None
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self.opened = False
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self.last_request = -1
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self.peer_mtu = 23
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self.generation += 1
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def expired(self):
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with self.lock:
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if self.owner is None:
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return False
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deadline = self.last_activity + 20 if self.opened else self.connected_at + 10
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return self.clock() >= deadline or (
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self.receiver.pending is not None and self.clock() - self.receiver.started >= 15)
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def status(self):
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with self.lock:
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return dict(connected=self.opened, client_name=self.client_name if self.opened else None,
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generation=self.generation)
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def accept(self, owner, fragment):
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with self.lock:
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if owner != self.owner or self.expired():
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raise ProtocolError("NOT_READY")
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message = self.receiver.accept(fragment)
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if message is None:
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return None
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kind, payload = message
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if self.cipher is None:
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if kind != 1:
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raise ProtocolError("NOT_READY")
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handshake = Handshake()
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self.cipher = handshake.finish(payload, server=True)
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return 2, handshake.hello
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if kind != 3:
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raise ProtocolError("BAD_REQUEST")
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from .protocol import json_object
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request = json_object(self.cipher.decrypt(payload))
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request_id = request.get("id")
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if not isinstance(request_id, str) or not 1 <= len(request_id) <= 64 or not request_id.isascii() or not request_id.isdecimal():
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raise ProtocolError("BAD_REQUEST")
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number = int(request_id)
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response = dict(id=request_id)
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try:
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if number <= self.last_request:
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raise RpcError("CONFLICT", "请求编号已使用")
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self.last_request = number
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method, params = request.get("method"), request.get("params")
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if not isinstance(method, str) or not isinstance(params, dict):
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raise RpcError("BAD_REQUEST", "请求格式无效")
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if not self.opened:
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if method != "session.open":
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raise ProtocolError("NOT_READY")
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name = checked_name(params.get("client_name"))
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peer_mtu = params.get('receive_mtu', 23)
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if type(peer_mtu) is not int or not 23 <= peer_mtu <= 517:
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raise RpcError('BAD_REQUEST', '接收分片上限无效')
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result = self.identity()
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self.peer_mtu = peer_mtu
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self.client_name = name
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self.opened = True
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self.generation += 1
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elif method == "session.ping":
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result = dict(alive=True)
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elif method == "session.rename":
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self.client_name = checked_name(params.get("client_name"))
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result = dict(client_name=self.client_name)
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elif method == "session.open":
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raise RpcError("CONFLICT", "会话已经建立")
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else:
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result = self.dispatch(method, params)
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response.update(ok=True, result=result)
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self.last_activity = self.clock()
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except RpcError as error:
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response.update(ok=False, error=dict(code=error.code, message=error.message, retryable=False))
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except ProtocolError:
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raise
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except Exception:
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response.update(ok=False, error=dict(code="DEVICE_ERROR", message="设备操作失败，请刷新状态", retryable=False))
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raw = json.dumps(response, ensure_ascii=False, separators=(",", ":"), allow_nan=False).encode("utf-8")
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return 3, self.cipher.encrypt(raw)
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