main.py

#
# Copyright(c) 2023 Swisscom (Schweiz) AG
# Authors: Marco Tollini, Leonardo Rodoni
# Distributed under the MIT License (http://opensource.org/licenses/MIT)
#

# External Libraries
import argparse
import yaml
import signal
import sys
import logging
import pathlib
from ast import arg
from time import time, sleep
from prettytable import PrettyTable
from threading import Thread
from queue import Queue
from scapy.all import IP, IPv6, TCP, UDP, raw, Raw

# Internal Libraries
from pcap_utils.filter import filter_generator
from client import Client
from packet_manager import PacketManager, PacketWithMetadata
from report import report
from proto import Proto
from process_pcap import PcapProcessing

def parse_args():
    parser = argparse.ArgumentParser(
        prog="main.py",
        description="Network Telemetry Traffic Reproducer: reproduce IPFIX/NetFlow, BGP and BMP Traffic based on pcap file.",
        epilog="-----------------------",
        formatter_class=argparse.RawTextHelpFormatter)

    parser.add_argument(
        "-t", "--test",
        type=pathlib.Path,
        dest='cfg',
        required=True,
        help="YAML configuration file path \n  --> set IPs and other parameters for reproduction, look at examples folder for some sample configs",
    )

    parser.add_argument(
        '-v', '--verbose',
        help="Set log level to INFO \n  --> default log level is WARNING, unless -d/--debug flag is used",
        action="store_const",
        dest="loglevel",
        const=logging.INFO,
        default=logging.WARNING,
    )

    parser.add_argument(
        '-d', '--debug',
        help="Set log level to DEBUG \n  --> default log level is WARNING, unless -v/--verbose flag is used",
        action="store_const",
        dest="loglevel",
        const=logging.DEBUG,
    )

    parser.add_argument(
        '-p', '--pcap-proc',
        help="Enable pcap pre-processing before reproducing \n  --> can also be used as standalone feature (pre-process and produce output pcap without reproducing) \n  --> requires pcap_processing entry in the config file, look at examples folder for some sample configs",
        action="store_const",
        dest="pcap_processing",
        const=True,
        default=False,
    )

    parser.add_argument(
        '--no-sync',
        help="Disable IPFIX bucket synchronization to the next full minute \n  --> also configurable through the config file [args OR config]",
        action="store_const",
        dest="nosync",
        const=True,
        default=False,
    )

    parser.add_argument(
        '--keep-open',
        help="Keep the TCP connections open when finishing the pcap reproduction \n  --> also configurable through the config file [args OR config]",
        action="store_const",
        dest="keep_open",
        const=True,
        default=False,
    )

    args = parser.parse_args()
    return args

def parse_config_file(cfg):
    with open(cfg, "r") as stream:
        return yaml.safe_load(stream)

# Pre-processing of the pcap file(s) s.t. it we can reproduce clean sessions with the reproducer
def pcap_processing(args, config):
    exit_flag = True
    if 'pcap_processing' in config:
        if 'exit' in config['pcap_processing']:
              exit_flag = config['pcap_processing']['exit']
        
    # Start pcap processing
    pp = PcapProcessing(config=config)
    pp_config = pp.start()

    # Exit if we only want pcap process (default behaviour)
    if exit_flag:
        logging.info("Exiting (exit=yes)...")
        sys.exit()
    
    # Replace config with new one and continue with reproduction
    logging.info("Starting repro...") 
    return pp_config

# create src_ip -> repro_ip mapping
def create_ip_map(network_map):
    table = PrettyTable(['src_ip', 'repro_ip'])

    ip_map = {}
    for m in network_map:
        ip_map[m['src_ip']] = m
        table.add_row([m['src_ip'], m['repro_ip']])

    logging.info(table)
    return ip_map

# Compute the inter-packet sleeping time based on inter-packet delay in the pcap
def sleep_between_pkts(packet, real_start_time, pcap_start_time, time_factor):
    elapsed_real_time = time() - real_start_time
    elapsed_pcap_time = float(packet.time - pcap_start_time)
    theoretical_sleep_time = elapsed_pcap_time * time_factor - elapsed_real_time

    # Reporting delay to give an idea if repro is behind schedule given by pcap intervals
    report.set_delay(min(theoretical_sleep_time, 0))  

    # Compute actual sleep_time (in 1ms intervals)
    sleep_time = round(max(theoretical_sleep_time - 0.01/time_factor, 0),3)

    # Some debug logs
    logging.debug(f"Elapsed pcap time: {elapsed_pcap_time}")
    logging.debug(f"Elapsed real time: {elapsed_real_time}")
    logging.debug(f"Multiplicative time factor: {time_factor}")
    logging.debug(f"Sleep time: {sleep_time}s [in 1ms steps]")

    return sleep_time

def main():
    # parse arguments
    args = parse_args()

    # initialize logging
    logging.basicConfig(level=args.loglevel)

    # parse test config file
    config = parse_config_file(args.cfg)

    # execute pcap pre-processing if required
    if args.pcap_processing:
        config = pcap_processing(args, config)

    # check if we want multithreading enabled
    is_threading = config['optimize']['threading']

    # protocol selectors
    supported_protos = [e.value for e in Proto]
    selectors = {}
    for proto in [proto for proto in supported_protos if proto in config]: 
        if 'select' in config[proto]:
            logging.info(f"{proto} repro selectors: {config[proto]['select']}")
            selectors[proto] = filter_generator(config[proto]['select'])
        else: 
            logging.info(f"{proto} repro selectors not defined: select all packets")
            selectors[proto] = filter_generator(False)

    # create src_ip -> repro_ip mapping (IP map)
    ip_map = create_ip_map(config['network']['map'])

    # map of clients
    clients = {}

    def stop_application(sig=None, frameg=None):
        if is_threading:
            logging.info("Shutting threading clients")
            for client in clients:
                queue = clients[client]['queue']
                queue.put(None)
            for client in clients:
                th = clients[client]['thread']
                th.join()

        if not is_threading:
            for client in clients:
                pclients = clients[client].pclients
                for pclient in pclients:
                    pc = pclients[pclient]
                    pc.should_run = False
                for pclient in pclients:
                    pc = pclients[pclient]
                    pc.receiving_thread.join()


        if report.is_alive():
            logging.info("Shutting down report thread")
            report.stop()
            report.join()
            logging.info("Printing last statistics")
            report.print_stats()

        sys.exit(0)

    signal.signal(signal.SIGINT, stop_application)

    # start reporting
    report.start_thread()

    # pcap timestamp for first packet sent
    pcap_start_time = None
    # real timestamp for first packet sent
    real_start_time = None

    # read pcap file and select packets according to selectors
    pm = PacketManager(
        pcap_path=config['pcap'],
        selectors=selectors,
        preload=config['optimize']['preload']
    )

    # start loop on pcap's packets
    packetwm: PacketWithMetadata
    for packetwm in pm:
        packet = packetwm.packet
        i = packetwm.number

        try:
            logging.debug(f"[{i}] start packet analysis")

            if IP in packet:
                ip_src = packet[IP].src
            elif IPv6 in packet:
                ip_src = packet[IPv6].src

            logging.debug(f"[{i}] has ip_src: {ip_src}")

            if ip_src not in ip_map:
                report.pkt_nopeer_countup()
                logging.debug(f"[{i}] discarded as {ip_src} not in IP Map (not specified as src_ip in config file)")
                continue

            if ip_src not in clients:
                network_map = ip_map[ip_src]
                collectors = {x: config[x]['collector'] for x in supported_protos if x in config}
                optimize_network = config['optimize']['network']
                network_interface = config['network']['interface']

                queue_th = Queue() if is_threading else None
                client = Client(
                    queue_th=queue_th,
                    network_map=network_map,
                    collectors=collectors,
                    optimize_network=optimize_network,
                    network_interface=network_interface,
                )

                if is_threading:
                    client_th = Thread(target=client.listen)
                    client_th.start()

                    clients[ip_src] = {
                        'thread': client_th,
                        'queue': queue_th,
                    }
                else:
                    clients[ip_src] = client

            # calculate sleep time (in between packets) and sleep
            if pcap_start_time is not None:
                sleep_time = sleep_between_pkts(packet, real_start_time, pcap_start_time, config['time_factor'])
                report.set_sleep(sleep_time)
                if sleep_time > 10:
                    logging.info(f"Sleeping for {sleep_time}s")
                sleep(sleep_time)


            # check if sync to ipfix bucket is necessary (before first packet is sent)
            should_sync_ipfix = pcap_start_time is None and not (args.nosync | config['no_sync'])

            # return 0 signifies that packet was not discared but program in multithreading
            sent = clients[ip_src].reproduce(packetwm, should_sync_ipfix=should_sync_ipfix)

            if pcap_start_time is None and sent >= 0:
                pcap_start_time = packet.time
                real_start_time = time()
                report.set_start_time(real_start_time)

            if is_threading:
                for ip_src in clients:
                    th = clients[ip_src]['thread']
                    if not th.is_alive():
                        raise Exception(f"Thread for {ip_src} is dead!")
        except Exception as e:
            logging.critical(f"Error! Stopping application on packet [{i}]: {e}")
            break

    if not (args.keep_open or config['keep_open']):
        print('Closing sockets and stopping application...')
        stop_application()

if __name__ == "__main__":
    main()