92 lines
3.0 KiB
Python
92 lines
3.0 KiB
Python
"""本地转发器的无状态报文解析与改写函数。"""
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from urllib.parse import urlsplit
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HTTP_METHODS = (
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b"CONNECT ", b"GET ", b"POST ", b"PUT ", b"DELETE ",
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b"HEAD ", b"OPTIONS ", b"PATCH ",
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)
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def starts_with_http_method(data: bytes) -> bool:
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return any(data.startswith(method) for method in HTTP_METHODS)
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def inject_proxy_auth(data: bytes, basic_auth: str) -> bytes:
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"""为完整 HTTP 代理请求注入上游 Basic Authorization。"""
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if not starts_with_http_method(data):
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return data
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end = data.find(b"\r\n\r\n")
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if end == -1:
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return data
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head = data[:end]
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first_end = head.find(b"\r\n")
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request_line = head if first_end == -1 else head[:first_end]
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headers = b"" if first_end == -1 else head[first_end + 2:]
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for line in headers.split(b"\r\n"):
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if b":" not in line:
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continue
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name = line[:line.index(b":")].strip().lower()
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if name == b"authorization":
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return data
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auth_line = f"Authorization: Basic {basic_auth}\r\n".encode()
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return request_line + b"\r\n" + auth_line + headers + data[end:]
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def parse_connect_authority(first_line: str):
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"""从 CONNECT 首行提取 ``(host, port)``，失败时返回 ``None``。"""
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parts = first_line.split(" ")
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if len(parts) < 2:
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return None
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authority = parts[1]
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if authority.startswith("[") and "]" in authority:
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try:
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host = authority[1:authority.index("]")]
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tail = authority[authority.index("]") + 1:]
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if tail.startswith(":") and tail[1:].isdigit():
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return host, int(tail[1:])
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except ValueError:
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pass
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if ":" not in authority:
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return None
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host, _, port_s = authority.rpartition(":")
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if not host or not port_s.isdigit():
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return None
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return host, int(port_s)
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def parse_http_absolute(first_line: str):
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"""从明文 HTTP 代理首行提取 ``(host, port)``，失败时返回 ``None``。"""
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parts = first_line.split(" ")
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if len(parts) < 2 or not parts[1].lower().startswith(("http://", "https://")):
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return None
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parsed = urlsplit(parts[1])
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if not parsed.hostname:
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return None
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port = parsed.port or (443 if parsed.scheme == "https" else 80)
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return parsed.hostname, port
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def force_http_close(buffer: bytes) -> bytes:
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"""直连明文 HTTP 时强制 Connection: close，避免错复用连接。"""
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end = buffer.find(b"\r\n\r\n")
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if end == -1:
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return buffer
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head, tail = buffer[:end], buffer[end:]
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lines = head.split(b"\r\n")
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out = [lines[0]]
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conn_seen = False
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for line in lines[1:]:
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low = line.lower()
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if low.startswith(b"connection:"):
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out.append(b"Connection: close")
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conn_seen = True
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elif low.startswith(b"proxy-connection:"):
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continue
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else:
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out.append(line)
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if not conn_seen:
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out.append(b"Connection: close")
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return b"\r\n".join(out) + tail
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