Distribution EOLE » Outils Eole » EWT

#!/usr/bin/python

import datetime, bisect

def parse_timestamp(raw_str):

        tokens = raw_str.split()

        if len(tokens) == 1:

                if tokens[0].lower() == 'never':

                        return 'never';

                else:

                        raise Exception('Parse error in timestamp')

        elif len(tokens) == 3:

                return datetime.datetime.strptime(' '.join(tokens[1:]),

                        '%Y/%m/%d %H:%M:%S')

        else:

                raise Exception('Parse error in timestamp')

def timestamp_is_ge(t1, t2):

        if t1 == 'never':

                return True

        elif t2 == 'never':

                return False

        else:

                return t1 >= t2

def timestamp_is_lt(t1, t2):

        if t1 == 'never':

                return False

        elif t2 == 'never':

                return t1 != 'never'

        else:

                return t1 < t2

def timestamp_is_between(t, tstart, tend):

        return timestamp_is_ge(t, tstart) and timestamp_is_lt(t, tend)

def parse_hardware(raw_str):

        tokens = raw_str.split()

        if len(tokens) == 2:

                return tokens[1]

        else:

                raise Exception('Parse error in hardware')

def strip_endquotes(raw_str):

        return raw_str.strip('"')

def identity(raw_str):

        return raw_str

def parse_binding_state(raw_str):

        tokens = raw_str.split()

        if len(tokens) == 2:

                return tokens[1]

        else:

                raise Exception('Parse error in binding state')

def parse_next_binding_state(raw_str):

        tokens = raw_str.split()

        if len(tokens) == 3:

                return tokens[2]

        else:

                raise Exception('Parse error in next binding state')

def parse_rewind_binding_state(raw_str):

        tokens = raw_str.split()

        if len(tokens) == 3:

                return tokens[2]

        else:

                raise Exception('Parse error in next binding state')

def parse_leases_file(leases_file):

        valid_keys = {

                'starts':               parse_timestamp,

                'ends':                 parse_timestamp,

                'tstp':                 parse_timestamp,

                'tsfp':                 parse_timestamp,

                'atsfp':                parse_timestamp,

                'cltt':                 parse_timestamp,

                'hardware':             parse_hardware,

                'binding':              parse_binding_state,

                'next':                 parse_next_binding_state,

                'rewind':               parse_rewind_binding_state,

                'uid':                  strip_endquotes,

                'client-hostname':      strip_endquotes,

                'option':               identity,

                'set':                  identity,

                'on':                   identity,

                'abandoned':            None,

                'bootp':                None,

                'reserved':             None,

                }

        leases_db = {}

        lease_rec = {}

        in_lease = False

        in_failover = False

        for line in leases_file:

                if line.lstrip().startswith('#'):

                        continue

                tokens = line.split()

                if len(tokens) == 0:

                        continue

                key = tokens[0].lower()

                if key == 'lease':

                        if not in_lease:

                                ip_address = tokens[1]

                                lease_rec = {'ip_address' : ip_address}

                                in_lease = True

                        else:

                                raise Exception('Parse error in leases file')

                elif key == 'failover':

                        in_failover = True

                elif key == '}':

                        if in_lease:

                                for k in valid_keys:

                                        if callable(valid_keys[k]):

                                                lease_rec[k] = lease_rec.get(k, '')

                                        else:

                                                lease_rec[k] = False

                                ip_address = lease_rec['ip_address']

                                if ip_address in leases_db:

                                        leases_db[ip_address].insert(0, lease_rec)

                                else:

                                        leases_db[ip_address] = [lease_rec]

                                lease_rec = {}

                                in_lease = False

                        elif in_failover:

                                in_failover = False

                                continue

                        else:

                                raise Exception('Parse error in leases file')

                elif key in valid_keys:

                        if in_lease:

                                value = line[(line.index(key) + len(key)):]

                                value = value.strip().rstrip(';').rstrip()

                                if callable(valid_keys[key]):

                                        lease_rec[key] = valid_keys[key](value)

                                else:

                                        lease_rec[key] = True

                        else:

                                raise Exception('Parse error in leases file')

                else:

                        if in_lease:

                                raise Exception('Parse error in leases file')

        if in_lease:

                raise Exception('Parse error in leases file')

        return leases_db

def round_timedelta(tdelta):

        return datetime.timedelta(tdelta.days,

                tdelta.seconds + (0 if tdelta.microseconds < 500000 else 1))

def timestamp_now():

        n = datetime.datetime.utcnow()

        return datetime.datetime(n.year, n.month, n.day, n.hour, n.minute,

                n.second + (0 if n.microsecond < 500000 else 1))

def lease_is_active(lease_rec, as_of_ts):

        return timestamp_is_between(as_of_ts, lease_rec['starts'],

                lease_rec['ends'])

def ipv4_to_int(ipv4_addr):

        parts = ipv4_addr.split('.')

        return (int(parts[0]) << 24) + (int(parts[1]) << 16) + \

                (int(parts[2]) << 8) + int(parts[3])

def select_active_leases(leases_db, as_of_ts):

        retarray = []

        sortedarray = []

        for ip_address in leases_db:

                lease_rec = leases_db[ip_address][0]

                if lease_is_active(lease_rec, as_of_ts):

                        ip_as_int = ipv4_to_int(ip_address)

                        insertpos = bisect.bisect(sortedarray, ip_as_int)

                        sortedarray.insert(insertpos, ip_as_int)

                        retarray.insert(insertpos, lease_rec)

        return retarray

##############################################################################

myfile = open('/var/lib/dhcp/dhcpd.leases', 'r')

leases = parse_leases_file(myfile)

myfile.close()

now = timestamp_now()

report_dataset = select_active_leases(leases, now)

print('+------------------------------------------------------------------------------')

print('| DHCPD ACTIVE LEASES REPORT')

print('+-----------------+-------------------+----------------------+-----------------')

print('| IP Address      | MAC Address       | Expires (days,H:M:S) | Client Hostname ')

print('+-----------------+-------------------+----------------------+-----------------')

for lease in report_dataset:

        print('| ' + format(lease['ip_address'], '<15') + ' | ' + \

                format(lease['hardware'], '<17') + ' | ' + \

                format(str((lease['ends'] - now) if lease['ends'] != 'never' else 'never'), '>20') + ' | ' + \

                lease['client-hostname'])

print('+-----------------+-------------------+----------------------+-----------------')

print('| Total Active Leases: ' + str(len(report_dataset)))

print('| Report generated (UTC): ' + str(now))

print('+------------------------------------------------------------------------------')