#!/usr/bin/env python3
# Generates samba network traffic
#
# Copyright (C) Catalyst IT Ltd. 2017
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
import sys
import os
import optparse
import tempfile
import shutil
import random

sys.path.insert(0, "bin/python")

from samba import gensec, get_debug_level
from samba.emulate import traffic
import samba.getopt as options
from samba.logger import get_samba_logger
from samba.samdb import SamDB
from samba.auth import system_session


def print_err(*args, **kwargs):
    print(*args, file=sys.stderr, **kwargs)


def main():

    desc = ("Generates network traffic 'conversations' based on a model generated"
            " by script/traffic_learner. This traffic is sent to <dns-hostname>,"
            " which is the full DNS hostname of the DC being tested.")

    parser = optparse.OptionParser(
        "%prog [--help|options] <model-file> <dns-hostname>",
        description=desc)

    parser.add_option('--dns-rate', type='float', default=0,
                      help='fire extra DNS packets at this rate')
    parser.add_option('--dns-query-file', dest="dns_query_file",
                      help='A file contains DNS query list')
    parser.add_option('-B', '--badpassword-frequency',
                      type='float', default=0.0,
                      help='frequency of connections with bad passwords')
    parser.add_option('-K', '--prefer-kerberos',
                      action="store_true",
                      help='prefer kerberos when authenticating test users')
    parser.add_option('-I', '--instance-id', type='int', default=0,
                      help='Instance number, when running multiple instances')
    parser.add_option('-t', '--timing-data',
                      help=('write individual message timing data here '
                            '(- for stdout)'))
    parser.add_option('--preserve-tempdir', default=False, action="store_true",
                      help='do not delete temporary files')
    parser.add_option('-F', '--fixed-password',
                      type='string', default=None,
                      help=('Password used for the test users created. '
                            'Required'))
    parser.add_option('-c', '--clean-up',
                      action="store_true",
                      help='Clean up the generated groups and user accounts')
    parser.add_option('--random-seed', type='int', default=None,
                      help='Use to keep randomness consistent across multiple runs')
    parser.add_option('--stop-on-any-error',
                      action="store_true",
                      help='abort the whole thing if a child fails')
    model_group = optparse.OptionGroup(parser, 'Traffic Model Options',
                                       'These options alter the traffic '
                                       'generated by the model')
    model_group.add_option('-S', '--scale-traffic', type='float',
                           help=('Increase the number of conversations by '
                                 'this factor (or use -T)'))
    parser.add_option('-T', '--packets-per-second', type=float,
                      help=('attempt this many packets per second '
                            '(alternative to -S)'))
    parser.add_option('--old-scale',
                      action="store_true",
                      help='emulate the old scale for traffic')
    model_group.add_option('-D', '--duration', type='float', default=60.0,
                           help=('Run model for this long (approx). '
                                 'Default 60s for models'))
    model_group.add_option('--latency-timeout', type='float', default=None,
                           help=('Wait this long for last packet to finish'))
    model_group.add_option('-r', '--replay-rate', type='float', default=1.0,
                           help='Replay the traffic faster by this factor')
    model_group.add_option('--conversation-persistence', type='float',
                           default=0.0,
                           help=('chance (0 to 1) that a conversation waits '
                                 'when it would have died'))
    model_group.add_option('--traffic-summary',
                           help=('Generate a traffic summary file and write '
                                 'it here (- for stdout)'))
    parser.add_option_group(model_group)

    user_gen_group = optparse.OptionGroup(parser, 'Generate User Options',
                                          "Add extra user/groups on the DC to "
                                          "increase the DB size. These extra "
                                          "users aren't used for traffic "
                                          "generation.")
    user_gen_group.add_option('-G', '--generate-users-only',
                              action="store_true",
                              help='Generate the users, but do not replay '
                              'the traffic')
    user_gen_group.add_option('-n', '--number-of-users', type='int', default=0,
                              help='Total number of test users to create')
    user_gen_group.add_option('--number-of-groups', type='int', default=None,
                              help='Create this many groups')
    user_gen_group.add_option('--average-groups-per-user',
                              type='int', default=0,
                              help='Assign the test users to this '
                              'many groups on average')
    user_gen_group.add_option('--group-memberships', type='int', default=0,
                              help='Total memberships to assign across all '
                              'test users and all groups')
    user_gen_group.add_option('--max-members', type='int', default=None,
                              help='Max users to add to any one group')
    parser.add_option_group(user_gen_group)

    sambaopts = options.SambaOptions(parser)
    parser.add_option_group(sambaopts)
    parser.add_option_group(options.VersionOptions(parser))
    credopts = options.CredentialsOptions(parser)
    parser.add_option_group(credopts)

    # the --no-password credential doesn't make sense for this tool
    if parser.has_option('-N'):
        parser.remove_option('-N')

    opts, args = parser.parse_args()

    # First ensure we have reasonable arguments

    if len(args) == 1:
        model_file = None
        host    = args[0]
    elif len(args) == 2:
        model_file, host = args
    else:
        parser.print_usage()
        return

    lp = sambaopts.get_loadparm()
    debuglevel = get_debug_level()
    logger = get_samba_logger(name=__name__,
                              verbose=debuglevel > 3,
                              quiet=debuglevel < 1)

    traffic.DEBUG_LEVEL = debuglevel
    # pass log level down to traffic module to make sure level is controlled
    traffic.LOGGER.setLevel(logger.getEffectiveLevel())

    if opts.clean_up:
        logger.info("Removing user and machine accounts")
        lp    = sambaopts.get_loadparm()
        creds = credopts.get_credentials(lp)
        creds.set_gensec_features(creds.get_gensec_features() | gensec.FEATURE_SEAL)
        ldb   = traffic.openLdb(host, creds, lp)
        traffic.clean_up_accounts(ldb, opts.instance_id)
        exit(0)

    if model_file:
        if not os.path.exists(model_file):
            logger.error("Model file %s doesn't exist" % model_file)
            sys.exit(1)
    # the model-file can be ommitted for --generate-users-only and
    # --cleanup-up, but it should be specified in all other cases
    elif not opts.generate_users_only:
        logger.error("No model file specified to replay traffic from")
        sys.exit(1)

    if not opts.fixed_password:
        logger.error(("Please use --fixed-password to specify a password"
                      " for the users created as part of this test"))
        sys.exit(1)

    if opts.random_seed is not None:
        random.seed(opts.random_seed)

    creds = credopts.get_credentials(lp)
    creds.set_gensec_features(creds.get_gensec_features() | gensec.FEATURE_SEAL)

    domain = creds.get_domain()
    if domain:
        lp.set("workgroup", domain)
    else:
        domain = lp.get("workgroup")
        if domain == "WORKGROUP":
            logger.error(("NETBIOS domain does not appear to be "
                          "specified, use the --workgroup option"))
            sys.exit(1)

    if not opts.realm and not lp.get('realm'):
        logger.error("Realm not specified, use the --realm option")
        sys.exit(1)

    if opts.generate_users_only and not (opts.number_of_users or
                                         opts.number_of_groups):
        logger.error(("Please specify the number of users and/or groups "
                      "to generate."))
        sys.exit(1)

    if opts.group_memberships and opts.average_groups_per_user:
        logger.error(("--group-memberships and --average-groups-per-user"
                      " are incompatible options - use one or the other"))
        sys.exit(1)

    if not opts.number_of_groups and opts.average_groups_per_user:
        logger.error(("--average-groups-per-user requires "
                      "--number-of-groups"))
        sys.exit(1)

    if opts.number_of_groups and opts.average_groups_per_user:
        if opts.number_of_groups < opts.average_groups_per_user:
            logger.error(("--average-groups-per-user can not be more than "
                          "--number-of-groups"))
            sys.exit(1)

    if not opts.number_of_groups and opts.group_memberships:
        logger.error("--group-memberships requires --number-of-groups")
        sys.exit(1)

    if opts.scale_traffic is not None and opts.packets_per_second is not None:
        logger.error("--scale-traffic and --packets-per-second "
                     "are incompatible. Use one or the other.")
        sys.exit(1)

    if not opts.scale_traffic and not opts.packets_per_second:
        logger.info("No packet rate specified. Using --scale-traffic=1.0")
        opts.scale_traffic = 1.0

    if opts.timing_data not in ('-', None):
        try:
            open(opts.timing_data, 'w').close()
        except IOError:
            # exception info will be added to log automatically
            logger.exception(("the supplied timing data destination "
                              "(%s) is not writable" % opts.timing_data))
            sys.exit()

    if opts.traffic_summary not in ('-', None):
        try:
            open(opts.traffic_summary, 'w').close()
        except IOError:
            # exception info will be added to log automatically
            if debuglevel > 0:
                import traceback
                traceback.print_exc()
            logger.exception(("the supplied traffic summary destination "
                              "(%s) is not writable" % opts.traffic_summary))
            sys.exit()

    if opts.old_scale:
        # we used to use a silly calculation based on the number
        # of conversations; now we use the number of packets and
        # scale traffic accurately. To roughly compare with older
        # numbers you use --old-scale which approximates as follows:
        opts.scale_traffic *= 0.55

    # ingest the model
    if model_file and not opts.generate_users_only:
        model = traffic.TrafficModel()
        try:
            model.load(model_file)
        except ValueError:
            if debuglevel > 0:
                import traceback
                traceback.print_exc()
            logger.error(("Could not parse %s, which does not seem to be "
                          "a model generated by script/traffic_learner."
                          % model_file))
            sys.exit(1)

        logger.info(("Using the specified model file to "
                     "generate conversations"))

        if opts.scale_traffic:
            packets_per_second = model.scale_to_packet_rate(opts.scale_traffic)
        else:
            packets_per_second =  opts.packets_per_second

        conversations = \
            model.generate_conversation_sequences(
                packets_per_second,
                opts.duration,
                opts.replay_rate,
                opts.conversation_persistence)
    else:
        conversations = []

    if opts.number_of_users and opts.number_of_users < len(conversations):
        logger.error(("--number-of-users (%d) is less than the "
                      "number of conversations to replay (%d)"
                     % (opts.number_of_users, len(conversations))))
        sys.exit(1)

    number_of_users = max(opts.number_of_users, len(conversations))

    if opts.number_of_groups is None:
        opts.number_of_groups = max(int(number_of_users / 10), 1)

    max_memberships = number_of_users * opts.number_of_groups

    if not opts.group_memberships and opts.average_groups_per_user:
        opts.group_memberships = opts.average_groups_per_user * number_of_users
        logger.info(("Using %d group-memberships based on %u average "
                     "memberships for %d users"
                     % (opts.group_memberships,
                        opts.average_groups_per_user, number_of_users)))

    if opts.group_memberships > max_memberships:
        logger.error(("The group memberships specified (%d) exceeds "
                      "the total users (%d) * total groups (%d)"
                      % (opts.group_memberships, number_of_users,
                         opts.number_of_groups)))
        sys.exit(1)

    # if no groups were specified by the user, then make sure we create some
    # group memberships (otherwise it's not really a fair test)
    if not opts.group_memberships and not opts.average_groups_per_user:
        opts.group_memberships = min(number_of_users * 5, max_memberships)

    # Get an LDB connection.
    try:
        # if we're only adding users, then it's OK to pass a sam.ldb filepath
        # as the host, which creates the users much faster. In all other cases
        # we should be connecting to a remote DC
        if opts.generate_users_only and os.path.isfile(host):
            ldb = SamDB(url="ldb://{0}".format(host),
                        session_info=system_session(), lp=lp)
        else:
            ldb = traffic.openLdb(host, creds, lp)
    except:
        logger.error(("\nInitial LDAP connection failed! Did you supply "
                      "a DNS host name and the correct credentials?"))
        sys.exit(1)

    if opts.generate_users_only:
        # generate computer accounts for added realism. Assume there will be
        # some overhang with more computer accounts than users
        computer_accounts = int(1.25 * number_of_users)
        traffic.generate_users_and_groups(ldb,
                                          opts.instance_id,
                                          opts.fixed_password,
                                          opts.number_of_users,
                                          opts.number_of_groups,
                                          opts.group_memberships,
                                          opts.max_members,
                                          machine_accounts=computer_accounts,
                                          traffic_accounts=False)
        sys.exit()

    tempdir = tempfile.mkdtemp(prefix="samba_tg_")
    logger.info("Using temp dir %s" % tempdir)

    traffic.generate_users_and_groups(ldb,
                                      opts.instance_id,
                                      opts.fixed_password,
                                      number_of_users,
                                      opts.number_of_groups,
                                      opts.group_memberships,
                                      opts.max_members,
                                      machine_accounts=len(conversations),
                                      traffic_accounts=True)

    accounts = traffic.generate_replay_accounts(ldb,
                                                opts.instance_id,
                                                len(conversations),
                                                opts.fixed_password)

    statsdir = traffic.mk_masked_dir(tempdir, 'stats')

    if opts.traffic_summary:
        if opts.traffic_summary == '-':
            summary_dest = sys.stdout
        else:
            summary_dest = open(opts.traffic_summary, 'w')

        logger.info("Writing traffic summary")
        summaries = []
        for c in traffic.seq_to_conversations(conversations):
            summaries += c.replay_as_summary_lines()

        summaries.sort()
        for (time, line) in summaries:
            print(line, file=summary_dest)

        exit(0)

    traffic.replay(conversations,
                   host,
                   lp=lp,
                   creds=creds,
                   accounts=accounts,
                   dns_rate=opts.dns_rate,
                   dns_query_file=opts.dns_query_file,
                   duration=opts.duration,
                   latency_timeout=opts.latency_timeout,
                   badpassword_frequency=opts.badpassword_frequency,
                   prefer_kerberos=opts.prefer_kerberos,
                   statsdir=statsdir,
                   domain=domain,
                   base_dn=ldb.domain_dn(),
                   ou=traffic.ou_name(ldb, opts.instance_id),
                   tempdir=tempdir,
                   stop_on_any_error=opts.stop_on_any_error,
                   domain_sid=ldb.get_domain_sid(),
                   instance_id=opts.instance_id)

    if opts.timing_data == '-':
        timing_dest = sys.stdout
    elif opts.timing_data is None:
        timing_dest = None
    else:
        timing_dest = open(opts.timing_data, 'w')

    logger.info("Generating statistics")
    traffic.generate_stats(statsdir, timing_dest)

    if not opts.preserve_tempdir:
        logger.info("Removing temporary directory")
        shutil.rmtree(tempdir)
    else:
        # delete the empty directories anyway. There are thousands of
        # them and they're EMPTY.
        for d in os.listdir(tempdir):
            if d.startswith('conversation-'):
                path = os.path.join(tempdir, d)
                try:
                    os.rmdir(path)
                except OSError as e:
                    logger.info("not removing %s (%s)" % (path, e))

main()