import os import asyncio import subprocess from packaging import version from pyshark.capture.capture import Capture from pyshark.tshark import tshark from pyshark.tshark.tshark import get_tshark_interfaces, get_process_path class UnknownInterfaceException(Exception): pass class LiveCapture(Capture): """Represents a live capture on a network interface.""" def __init__(self, interface=None, bpf_filter=None, display_filter=None, only_summaries=False, decryption_key=None, encryption_type='wpa-pwk', output_file=None, decode_as=None, disable_protocol=None, tshark_path=None, override_prefs=None, capture_filter=None, monitor_mode=False, use_json=False, use_ek=False, include_raw=False, eventloop=None, custom_parameters=None, debug=False): """Creates a new live capturer on a given interface. Does not start the actual capture itself. :param interface: Name of the interface to sniff on or a list of names (str). If not given, runs on all interfaces. :param bpf_filter: BPF filter to use on packets. :param display_filter: Display (wireshark) filter to use. :param only_summaries: Only produce packet summaries, much faster but includes very little information :param decryption_key: Optional key used to encrypt and decrypt captured traffic. :param encryption_type: Standard of encryption used in captured traffic (must be either 'WEP', 'WPA-PWD', or 'WPA-PWK'. Defaults to WPA-PWK). :param output_file: Additionally save live captured packets to this file. :param decode_as: A dictionary of {decode_criterion_string: decode_as_protocol} that are used to tell tshark to decode protocols in situations it wouldn't usually, for instance {'tcp.port==8888': 'http'} would make it attempt to decode any port 8888 traffic as HTTP. See tshark documentation for details. :param tshark_path: Path of the tshark binary :param override_prefs: A dictionary of tshark preferences to override, {PREFERENCE_NAME: PREFERENCE_VALUE, ...}. :param capture_filter: Capture (wireshark) filter to use. :param disable_protocol: Tells tshark to remove a dissector for a specifc protocol. :param use_ek: Uses tshark in EK JSON mode. It is faster than XML but has slightly less data. :param use_json: DEPRECATED. Use use_ek instead. :param custom_parameters: A dict of custom parameters to pass to tshark, i.e. {"--param": "value"} or else a list of parameters in the format ["--foo", "bar", "--baz", "foo"]. """ super(LiveCapture, self).__init__(display_filter=display_filter, only_summaries=only_summaries, decryption_key=decryption_key, encryption_type=encryption_type, output_file=output_file, decode_as=decode_as, disable_protocol=disable_protocol, tshark_path=tshark_path, override_prefs=override_prefs, capture_filter=capture_filter, use_json=use_json, use_ek=use_ek, include_raw=include_raw, eventloop=eventloop, custom_parameters=custom_parameters, debug=debug) self.bpf_filter = bpf_filter self.monitor_mode = monitor_mode all_interfaces = get_tshark_interfaces(tshark_path) if interface is None: self.interfaces = all_interfaces elif isinstance(interface, str): self.interfaces = [interface] else: self.interfaces = interface def get_parameters(self, packet_count=None): """Returns the special tshark parameters to be used according to the configuration of this class.""" params = super(LiveCapture, self).get_parameters(packet_count=packet_count) # Read from STDIN params += ["-i", "-"] return params def _verify_capture_parameters(self): all_interfaces_names = tshark.get_all_tshark_interfaces_names(self.tshark_path) all_interfaces_lowercase = [interface.lower() for interface in all_interfaces_names] for each_interface in self.interfaces: if each_interface.startswith("rpcap://"): continue if each_interface.isnumeric(): continue if each_interface.lower() not in all_interfaces_lowercase: raise UnknownInterfaceException( f"Interface '{each_interface}' does not exist, unable to initiate capture. " f"Perhaps permissions are missing?\n" f"Possible interfaces: {os.linesep.join(all_interfaces_names)}") def _get_dumpcap_parameters(self): # Don't report packet counts. params = ["-q"] if self._get_tshark_version() < version.parse("2.5.0"): # Tshark versions older than 2.5 don't support pcapng. This flag forces dumpcap to output pcap. params += ["-P"] if self.bpf_filter: params += ["-f", self.bpf_filter] if self.monitor_mode: params += ["-I"] for interface in self.interfaces: params += ["-i", interface] # Write to STDOUT params += ["-w", "-"] return params async def _get_tshark_process(self, packet_count=None, stdin=None): read, write = os.pipe() dumpcap_params = [get_process_path(process_name="dumpcap", tshark_path=self.tshark_path)] + self._get_dumpcap_parameters() self._log.debug("Creating Dumpcap subprocess with parameters: %s", " ".join(dumpcap_params)) dumpcap_process = await asyncio.create_subprocess_exec(*dumpcap_params, stdout=write, stderr=subprocess.PIPE) self._create_stderr_handling_task(dumpcap_process.stderr) self._created_new_process(dumpcap_params, dumpcap_process, process_name="Dumpcap") tshark = await super(LiveCapture, self)._get_tshark_process(packet_count=packet_count, stdin=read) return tshark # Backwards compatibility sniff = Capture.load_packets def sniff_continuously(self, packet_count=None): """Captures from the set interface, returning a generator which returns packets continuously. Can be used as follows: for packet in capture.sniff_continuously(): print('Woo, another packet:', packet) Note: you can also call capture.apply_on_packets(packet_callback) which should have a slight performance boost. :param packet_count: an amount of packets to capture, then stop. """ # Retained for backwards compatibility and to add documentation. return self._packets_from_tshark_sync(packet_count=packet_count)