130 lines
4.2 KiB
Python
130 lines
4.2 KiB
Python
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"""L2 本地 HTTP 透明代理(软路由侧, 监听 8080)。
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iptables 把 LAN 出向 dport 80 的明文 HTTP REDIRECT 到这里:
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1. recv 请求(头 + Content-Length body)
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2. 原始字节打包走通道(云端负责 https 套壳)
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3. 响应原样写回客户端后关闭连接(每个请求一条连接)
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连接断/通道错误 -> 502。目标为内网段(学校)的流量被 hook 规则排除,
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不会到本代理。
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"""
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from __future__ import annotations
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import socket
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import threading
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from typing import Any
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from .client import ChannelClient, ChannelError
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from .httpmsg import parse_request_head
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LISTEN_BACKLOG = 128
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MAX_HEAD = 64 * 1024
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class HttpTransparentProxy:
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def __init__(self, client: ChannelClient, listen_port: int) -> None:
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if listen_port < 1 or listen_port > 65535:
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raise ValueError(f"bad listen port: {listen_port}")
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self.client = client
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self.port = listen_port
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self.served = 0
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self.failed = 0
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def serve(self) -> None:
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srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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srv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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srv.bind(("0.0.0.0", self.port))
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srv.listen(LISTEN_BACKLOG)
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print(f"[http-proxy] listen 0.0.0.0:{self.port}", flush=True)
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while True:
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conn, _addr = srv.accept()
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threading.Thread(
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target=self._handle,
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args=(conn,),
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name="http-proxy-conn",
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daemon=True,
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).start()
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def _recv_request(self, conn: socket.socket) -> bytes | None:
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buf = bytearray()
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while len(buf) < MAX_HEAD:
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chunk = conn.recv(8192)
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if not chunk:
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return None
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buf += chunk
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parsed = parse_request_head(bytes(buf))
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if parsed is None:
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continue
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_req, head_len = parsed
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content_length = 0
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for key, value in _req.headers:
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if key.lower() == "content-length":
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try:
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content_length = int(value)
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except ValueError:
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content_length = 0
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total = head_len + content_length
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if len(buf) >= total:
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return bytes(buf[:total])
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if content_length > MAX_HEAD:
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return None
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return None
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def _handle(self, conn: socket.socket) -> None:
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try:
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conn.settimeout(30)
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raw = self._recv_request(conn)
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if raw is None:
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return
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resp = self._channel_send(raw)
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if resp is None:
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self._write_502(conn)
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self.failed += 1
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return
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conn.sendall(resp)
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self.served += 1
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except OSError:
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self.failed += 1
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finally:
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try:
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conn.close()
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except OSError:
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pass
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def _channel_send(self, raw: bytes) -> bytes | None:
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try:
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return self.client.send_http_request(raw)
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except ChannelError:
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try:
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self.client.ensure_connected()
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return self.client.send_http_request(raw)
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except ChannelError:
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return None
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def _write_502(self, conn: socket.socket) -> None:
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body = b"<html><body><h1>502 Bad Gateway</h1>"
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body += b"<p>channel unavailable</p></body></html>"
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head = (
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b"HTTP/1.1 502 Bad Gateway\r\n"
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b"Content-Type: text/html; charset=utf-8\r\n"
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+ f"Content-Length: {len(body)}\r\n".encode("ascii")
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+ b"Connection: close\r\n\r\n"
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)
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try:
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conn.sendall(head + body)
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except OSError:
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pass
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def run_http_proxy(cfg: dict[str, Any]) -> None:
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cloud: dict[str, Any] = cfg["cloud"]
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proxy_cfg: dict[str, Any] = cfg["http_proxy"]
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client = ChannelClient(
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host=str(cloud["host"]),
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port=int(cloud["port"]),
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token=str(cloud["token"]),
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ca_path=str(cloud.get("ca_path", "")),
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heartbeat=float(cfg.get("heartbeat", 30)),
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)
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client.connect()
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HttpTransparentProxy(client, int(proxy_cfg["listen_port"])).serve()
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