bmp_filter.py

#!/usr/bin/env python
"""
  Copyright (c) 2022 Marco Tollini <marco.tollini1@swisscom.com>

  Permission to use, copy, modify, and distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""

import argparse
import mmap

message_type_map = {
    0: "Route Monitoring",
    1: "Statistics Report",
    2: "Peer Down Notification",
    3: "Peer Up Notification",
    4: "Initiation Message",
    5: "Termination Message",
    6: "Route Mirroring Message",
}


class Statistics:
    def __init__(self):
        self.kept = {
            0: 0,
            1: 0,
            2: 0,
            3: 0,
            4: 0,
            5: 0,
            6: 0,
        }

        self.discarded = {
            0: 0,
            1: 0,
            2: 0,
            3: 0,
            4: 0,
            5: 0,
            6: 0,
        }

    def print(self):
        print(f'### PACKETS KEPT ###')
        print(f'Route Monitoring:\t\t{self.kept[0]}')
        print(f'Statistics Report:\t\t{self.kept[1]}')
        print(f'Peer Down Notification:\t\t{self.kept[2]}')
        print(f'Peer Up Notification:\t\t{self.kept[3]}')
        print(f'Initiation Message:\t\t{self.kept[4]}')
        print(f'Termination Message:\t\t{self.kept[5]}')
        print(f'Route Mirroring Message:\t{self.kept[6]}')

        print(f'### PACKETS DISCARDED ###')
        print(f'Route Monitoring:\t\t{self.discarded[0]}')
        print(f'Statistics Report:\t\t{self.discarded[1]}')
        print(f'Peer Down Notification:\t\t{self.discarded[2]}')
        print(f'Peer Up Notification:\t\t{self.discarded[3]}')
        print(f'Initiation Message:\t\t{self.discarded[4]}')
        print(f'Termination Message:\t\t{self.discarded[5]}')
        print(f'Route Mirroring Message:\t{self.discarded[6]}')


def parse_args():
    parser = argparse.ArgumentParser(
        description='Filter BMP message from record')
    parser.add_argument(
        '-i',
        '--input',
        dest="input",
        type=str,
        required=True,
        help="Input file",
    )

    parser.add_argument(
        '-o',
        '--output',
        dest="output",
        type=str,
        required=True,
        help="Output file",
    )

    parser.add_argument(
        '--route-monitoring',
        dest="rm",
        action='store_true',
        help="Include router monitoring messages",
    )

    parser.add_argument(
        '--statistics-report',
        dest="stats",
        action='store_true',
        help="Include Statistics Report messages",
    )

    parser.add_argument(
        '--peer-down',
        dest="pd",
        action='store_true',
        help="Include Peer Down Notification messages",
    )

    parser.add_argument(
        '--peer-up',
        dest="pu",
        action='store_true',
        help="Include Peer Up Notification messages",
    )

    parser.add_argument(
        '--initiation',
        dest="init",
        action='store_true',
        help="Include Initiation Message messages",
    )

    parser.add_argument(
        '--termination',
        dest="term",
        action='store_true',
        help="Include Termination Message messages",
    )

    parser.add_argument(
        '-m',
        '--route-mirroring',
        dest="rmirror",
        action='store_true',
        help="Include Route Mirroring messages",
    )

    args = parser.parse_args()
    return args


def args_to_filter_map(args):
    return {
        0: not args.rm,
        1: not args.stats,
        2: not args.pd,
        3: not args.pu,
        4: not args.init,
        5: not args.term,
        6: not args.rmirror,
    }


def decode_common_header(header):
    version = int(header[0])
    msg_length = int.from_bytes(header[1:5], byteorder='big', signed=False)
    msg_type = header[5]
    return version, msg_length, msg_type


def main():
    args = parse_args()
    filter_map = args_to_filter_map(args)
    statistics = Statistics()

    with open(args.input, 'rb') as inp:
        with mmap.mmap(inp.fileno(), 0, access=mmap.ACCESS_READ) as inp_map:
            with open(args.output, 'wb') as out:
                head = 0
                while head < len(inp_map):
                    version, msg_length, msg_type = decode_common_header(
                        inp_map[head:head+6])
                    if not filter_map[msg_type]:
                        statistics.kept[msg_type] += 1
                        out.write(inp_map[head:head+msg_length])
                    else:
                        statistics.discarded[msg_type] += 1

                    head += msg_length
    statistics.print()


if __name__ == '__main__':
    main()