304 lines
12 KiB
Python
304 lines
12 KiB
Python
import socket
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import os
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from firegex.nfproxy.internals import get_filter_names
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import traceback
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from multiprocessing import Process
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from firegex.nfproxy import ACCEPT, DROP, REJECT, UNSTABLE_MANGLE
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from rich.markup import escape
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from rich import print
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import asyncio
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from watchfiles import awatch, Change
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fake_ip_header = b"FAKE:IP:TCP:HEADERS:"
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fake_ip_header_len = len(fake_ip_header)
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MANGLE_WARNING = True
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class LogLevels:
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INFO = "INFO"
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WARNING = "WARNING"
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ERROR = "ERROR"
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DEBUG = "DEBUG"
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def load_level_str(level:str):
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if level is None:
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return ""
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match level:
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case LogLevels.INFO:
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return "[chartreuse4 bold]\\[INFO][/]"
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case LogLevels.WARNING:
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return "[yellow bold]\\[WARNING][/]"
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case LogLevels.ERROR:
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return "[red bold]\\[ERROR][/]"
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case LogLevels.DEBUG:
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return "[blue bold]\\[DEBUG][/]"
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case _:
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return f"\\[[red bold]{escape(level)}[/]]"
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def log_print(module:str, *args, level:str = LogLevels.INFO, **kwargs):
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return print(f"{load_level_str(level)}[deep_pink4 bold]\\[nfproxy][/][medium_orchid3 bold]\\[{escape(module)}][/]", *args, **kwargs)
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async def _watch_filter_file(filter_file: str, reload_action):
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abs_path = os.path.abspath(filter_file)
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directory = os.path.dirname(abs_path)
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# Immediately call the reload action on startup.
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if reload_action is not None:
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reload_action()
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log_print("observer", f"Listening for changes on {escape(abs_path)}")
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try:
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# Monitor the directory; set recursive=False since we only care about the specific file.
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async for changes in awatch(directory, recursive=False):
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# Process events and filter for our file.
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for change in changes:
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event, path = change
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if os.path.abspath(path) == abs_path:
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# Optionally, you can check the event type:
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if event in {Change.modified, Change.deleted}:
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if reload_action is not None:
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reload_action()
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except asyncio.CancelledError:
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log_print("observer", "Watcher cancelled, stopping.")
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async def _forward_and_filter(filter_ctx: dict,
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reader: asyncio.StreamReader,
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writer: asyncio.StreamWriter,
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is_input: bool,
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is_ipv6: bool,
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is_tcp: bool,
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has_to_filter: bool = True):
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"""Asynchronously forward data from reader to writer applying filters."""
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try:
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has_to_drop = False
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while True:
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try:
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data = await reader.read(4096)
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except Exception:
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break
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if not data:
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break
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if has_to_drop:
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continue
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if has_to_filter:
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filter_ctx["__firegex_packet_info"] = {
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"data": data,
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"l4_size": len(data),
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"raw_packet": fake_ip_header + data,
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"is_input": is_input,
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"is_ipv6": is_ipv6,
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"is_tcp": is_tcp
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}
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try:
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exec("firegex.nfproxy.internals.handle_packet(globals())", filter_ctx, filter_ctx)
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except Exception as e:
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log_print("packet-handling",
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f"Error while executing filter: {escape(str(e))}, forwarding normally from now",
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level=LogLevels.ERROR)
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traceback.print_exc()
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# Stop filtering and forward the packet as is.
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has_to_filter = False
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writer.write(data)
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await writer.drain()
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continue
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finally:
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filter_ctx.pop("__firegex_packet_info", None)
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result = filter_ctx.pop("__firegex_pyfilter_result", None)
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if result is None or not isinstance(result, dict):
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log_print("filter-parsing", "No result found", level=LogLevels.ERROR)
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has_to_filter = False
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writer.write(data)
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await writer.drain()
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continue
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action = result.get("action")
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if action is None or not isinstance(action, int):
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log_print("filter-parsing", "No action found", level=LogLevels.ERROR)
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has_to_filter = False
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writer.write(data)
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await writer.drain()
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continue
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if action == ACCEPT.value:
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writer.write(data)
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await writer.drain()
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continue
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filter_name = result.get("matched_by")
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if filter_name is None or not isinstance(filter_name, str):
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log_print("filter-parsing", "No matched_by found", level=LogLevels.ERROR)
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has_to_filter = False
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writer.write(data)
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await writer.drain()
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continue
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if action == DROP.value:
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log_print("drop-action", "Dropping connection caused by {escape(filter_name)} pyfilter")
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has_to_drop = True
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continue
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if action == REJECT.value:
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log_print("reject-action", f"Rejecting connection caused by {escape(filter_name)} pyfilter")
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writer.close()
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await writer.wait_closed()
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return
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elif action == UNSTABLE_MANGLE.value:
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mangled_packet = result.get("mangled_packet")
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if mangled_packet is None or not isinstance(mangled_packet, bytes):
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log_print("filter-parsing", "No mangled_packet found", level=LogLevels.ERROR)
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has_to_filter = False
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writer.write(data)
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await writer.drain()
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continue
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log_print("mangle", f"Mangling packet caused by {escape(filter_name)} pyfilter")
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if MANGLE_WARNING:
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log_print("mangle",
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"In the real execution mangling is not so stable as the simulation does, l4_data can be different by data",
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level=LogLevels.WARNING)
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writer.write(mangled_packet[fake_ip_header_len:])
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await writer.drain()
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continue
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else:
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log_print("filter-parsing", f"Invalid action {action} found", level=LogLevels.ERROR)
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has_to_filter = False
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writer.write(data)
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await writer.drain()
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continue
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else:
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writer.write(data)
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await writer.drain()
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except Exception as exc:
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log_print("forward_and_filter", f"Exception occurred: {escape(str(exc))}", level=LogLevels.ERROR)
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finally:
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writer.close()
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try:
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await writer.wait_closed()
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except Exception:
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pass
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async def _handle_connection(
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reader: asyncio.StreamReader, writer: asyncio.StreamWriter, filter_code: str,
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target_ip: str, target_port: int, ipv6: bool):
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"""Handle a new incoming connection and create a remote connection."""
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addr = writer.get_extra_info('peername')
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log_print("listener", f"Accepted connection from {escape(addr[0])}:{addr[1]}")
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try:
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remote_reader, remote_writer = await asyncio.open_connection(
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target_ip, target_port,
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family=socket.AF_INET6 if ipv6 else socket.AF_INET)
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except Exception as e:
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log_print("listener",
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f"Could not connect to remote {escape(target_ip)}:{target_port}: {escape(str(e))}",
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level=LogLevels.ERROR)
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writer.close()
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await writer.wait_closed()
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return
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try:
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filter_ctx = {}
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exec(filter_code, filter_ctx, filter_ctx)
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except Exception as e:
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log_print("listener",
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f"Error while compiling filter context: {escape(str(e))}, forwarding normally",
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level=LogLevels.ERROR)
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traceback.print_exc()
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filter_ctx = {}
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# Create asynchronous tasks for bidirectional forwarding.
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task1 = asyncio.create_task(_forward_and_filter(filter_ctx, reader, remote_writer, True, ipv6, True, True))
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task2 = asyncio.create_task(_forward_and_filter(filter_ctx, remote_reader, writer, False, ipv6, True, True))
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try:
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await asyncio.gather(task1, task2)
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except (KeyboardInterrupt, asyncio.CancelledError):
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task1.cancel()
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task2.cancel()
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await asyncio.gather(task1, task2)
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finally:
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remote_writer.close()
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await remote_writer.wait_closed()
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async def _execute_proxy(
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filter_code: str,
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target_ip: str, target_port: int,
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local_ip: str = "127.0.0.1", local_port: int = 7474,
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ipv6: bool = False
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):
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"""Start the asyncio-based TCP proxy server."""
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addr_family = socket.AF_INET6 if ipv6 else socket.AF_INET
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server = await asyncio.start_server(
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lambda r, w: _handle_connection(r, w, filter_code, target_ip, target_port, ipv6),
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local_ip, local_port, family=addr_family)
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log_print("listener", f"TCP proxy listening on {escape(local_ip)}:{local_port} and forwarding to -> {escape(target_ip)}:{target_port}")
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async with server:
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await server.serve_forever()
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def _proxy_asyncio_runner(filter_code: str, target_ip: str, target_port: int, local_ip: str, local_port: int, ipv6: bool):
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try:
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return asyncio.run(_execute_proxy(filter_code, target_ip, target_port, local_ip, local_port, ipv6))
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except KeyboardInterrupt:
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log_print("listener", "Proxy server stopped", level=LogLevels.WARNING)
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def _build_filter(filepath:str, proto:str):
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if os.path.isfile(filepath) is False:
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raise Exception(f"Filter file {filepath} not found")
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with open(filepath, "r") as f:
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filter_code = f.read()
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filters = get_filter_names(filter_code, proto)
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filter_code += (
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"\n\n__firegex_pyfilter_enabled = [" + ", ".join([repr(f) for f in filters]) + "]\n"
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"__firegex_proto = " + repr(proto) + "\n"
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"import firegex.nfproxy.internals\n"
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"firegex.nfproxy.internals.compile(globals())\n"
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)
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filter_glob = {}
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exec(filter_code, filter_glob, filter_glob) # test compilation of filters
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return filter_code
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def run_proxy_simulation(filter_file:str, proto:str, target_ip:str, target_port:int, local_ip:str = None, local_port:int = 7474, ipv6:bool = False):
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if local_ip is None:
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if ipv6:
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local_ip = "::1"
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else:
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local_ip = "127.0.0.1"
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if os.path.isfile(filter_file) is False:
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raise Exception(f"\\[nfproxy]\\[init] Filter file {filter_file} not found")
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else:
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filter_file = os.path.abspath(filter_file)
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proxy_process:Process|None = None
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def reload_proxy_proc():
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nonlocal proxy_process
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if proxy_process is not None:
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log_print("RELOADING", "Proxy reload triggered", level=LogLevels.WARNING)
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proxy_process.kill()
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proxy_process.join()
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proxy_process = None
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compiled_filter = None
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try:
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compiled_filter = _build_filter(filter_file, proto)
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except Exception:
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log_print("reloader", f"Failed to build filter {escape(filter_file)}!", level=LogLevels.ERROR)
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traceback.print_exc()
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if compiled_filter is not None:
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proxy_process = Process(target=_proxy_asyncio_runner, args=(compiled_filter, target_ip, target_port, local_ip, local_port, ipv6))
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proxy_process.start()
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try:
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asyncio.run(_watch_filter_file(filter_file, reload_proxy_proc))
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except KeyboardInterrupt:
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pass
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finally:
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if proxy_process is not None:
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proxy_process.kill()
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proxy_process.join()
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