packages/antlion/controllers/sniffer_lib/local/tshark.py

#!/usr/bin/env python3

# Copyright 2022 The Fuchsia Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import shutil

from antlion.controllers import sniffer
from antlion.controllers.sniffer_lib.local import local_base


class Sniffer(local_base.SnifferLocalBase):
    """This class defines a sniffer which uses tshark as its back-end"""

    def __init__(self, config_path, logger, base_configs=None):
        """See base class documentation"""
        self._executable_path = None

        super().__init__(config_path, logger, base_configs=base_configs)

        self._executable_path = shutil.which("tshark") or shutil.which(
            "/usr/local/bin/tshark"
        )
        if self._executable_path is None:
            raise sniffer.SnifferError(
                "Cannot find a path to the 'tshark' "
                "executable (or to '/usr/local/bin/tshark')"
            )

    def get_descriptor(self):
        """See base class documentation"""
        return "local-tshark-{}-ch{}".format(self._interface)

    def get_subtype(self):
        """See base class documentation"""
        return "tshark"

    def _get_command_line(self, additional_args=None, duration=None, packet_count=None):
        cmd = "{} -i {} -w {}".format(
            self._executable_path, self._interface, self._temp_capture_file_path
        )
        if duration is not None:
            cmd = f"{cmd} -a duration:{duration}"
        if packet_count is not None:
            cmd = f"{cmd} -c {packet_count}"
        if additional_args is not None:
            cmd = f"{cmd} {additional_args}"
        return cmd