261 lines
8.2 KiB
Python
261 lines
8.2 KiB
Python
#!/usr/bin/python
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# source: http://askubuntu.com/revisions/fb67e8e2-efd4-4d0e-bb2f-416855fd8369/view-source
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# by http://askubuntu.com/users/499043/dfsmith
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import datetime, bisect
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def parse_timestamp(raw_str):
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tokens = raw_str.split()
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if len(tokens) == 1:
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if tokens[0].lower() == 'never':
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return 'never';
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else:
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raise Exception('Parse error in timestamp')
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elif len(tokens) == 3:
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return datetime.datetime.strptime(' '.join(tokens[1:]),
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'%Y/%m/%d %H:%M:%S')
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else:
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raise Exception('Parse error in timestamp')
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def timestamp_is_ge(t1, t2):
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if t1 == 'never':
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return True
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elif t2 == 'never':
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return False
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else:
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return t1 >= t2
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def timestamp_is_lt(t1, t2):
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if t1 == 'never':
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return False
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elif t2 == 'never':
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return t1 != 'never'
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else:
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return t1 < t2
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def timestamp_is_between(t, tstart, tend):
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return timestamp_is_ge(t, tstart) and timestamp_is_lt(t, tend)
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def parse_hardware(raw_str):
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tokens = raw_str.split()
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if len(tokens) == 2:
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return tokens[1]
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else:
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raise Exception('Parse error in hardware')
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def strip_endquotes(raw_str):
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return raw_str.strip('"')
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def identity(raw_str):
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return raw_str
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def parse_binding_state(raw_str):
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tokens = raw_str.split()
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if len(tokens) == 2:
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return tokens[1]
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else:
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raise Exception('Parse error in binding state')
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def parse_next_binding_state(raw_str):
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tokens = raw_str.split()
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if len(tokens) == 3:
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return tokens[2]
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else:
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raise Exception('Parse error in next binding state')
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def parse_rewind_binding_state(raw_str):
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tokens = raw_str.split()
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if len(tokens) == 3:
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return tokens[2]
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else:
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raise Exception('Parse error in next binding state')
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def parse_leases_file(leases_file):
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valid_keys = {
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'starts': parse_timestamp,
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'ends': parse_timestamp,
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'tstp': parse_timestamp,
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'tsfp': parse_timestamp,
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'atsfp': parse_timestamp,
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'cltt': parse_timestamp,
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'hardware': parse_hardware,
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'binding': parse_binding_state,
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'next': parse_next_binding_state,
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'rewind': parse_rewind_binding_state,
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'uid': strip_endquotes,
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'client-hostname': strip_endquotes,
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'option': identity,
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'set': identity,
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'on': identity,
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'abandoned': None,
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'bootp': None,
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'reserved': None,
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}
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leases_db = {}
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lease_rec = {}
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in_lease = False
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in_failover = False
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for line in leases_file:
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if line.lstrip().startswith('#'):
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continue
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tokens = line.split()
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if len(tokens) == 0:
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continue
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key = tokens[0].lower()
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if key == 'lease':
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if not in_lease:
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ip_address = tokens[1]
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lease_rec = {'ip_address' : ip_address}
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in_lease = True
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else:
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raise Exception('Parse error in leases file')
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elif key == 'failover':
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in_failover = True
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elif key == '}':
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if in_lease:
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for k in valid_keys:
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if callable(valid_keys[k]):
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lease_rec[k] = lease_rec.get(k, '')
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else:
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lease_rec[k] = False
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ip_address = lease_rec['ip_address']
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if ip_address in leases_db:
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leases_db[ip_address].insert(0, lease_rec)
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else:
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leases_db[ip_address] = [lease_rec]
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lease_rec = {}
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in_lease = False
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elif in_failover:
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in_failover = False
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continue
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else:
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raise Exception('Parse error in leases file')
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elif key in valid_keys:
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if in_lease:
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value = line[(line.index(key) + len(key)):]
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value = value.strip().rstrip(';').rstrip()
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if callable(valid_keys[key]):
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lease_rec[key] = valid_keys[key](value)
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else:
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lease_rec[key] = True
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else:
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raise Exception('Parse error in leases file')
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else:
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if in_lease:
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raise Exception('Parse error in leases file')
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if in_lease:
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raise Exception('Parse error in leases file')
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return leases_db
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def round_timedelta(tdelta):
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return datetime.timedelta(tdelta.days,
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tdelta.seconds + (0 if tdelta.microseconds < 500000 else 1))
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def timestamp_now():
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n = datetime.datetime.utcnow()
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return datetime.datetime(n.year, n.month, n.day, n.hour, n.minute,
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n.second + (0 if n.microsecond < 500000 else 1))
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def lease_is_active(lease_rec, as_of_ts):
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return timestamp_is_between(as_of_ts, lease_rec['starts'],
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lease_rec['ends'])
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def ipv4_to_int(ipv4_addr):
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parts = ipv4_addr.split('.')
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return (int(parts[0]) << 24) + (int(parts[1]) << 16) + \
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(int(parts[2]) << 8) + int(parts[3])
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def select_active_leases(leases_db, as_of_ts):
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retarray = []
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sortedarray = []
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for ip_address in leases_db:
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lease_rec = leases_db[ip_address][0]
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if lease_is_active(lease_rec, as_of_ts):
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ip_as_int = ipv4_to_int(ip_address)
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insertpos = bisect.bisect(sortedarray, ip_as_int)
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sortedarray.insert(insertpos, ip_as_int)
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retarray.insert(insertpos, lease_rec)
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return retarray
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##############################################################################
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myfile = open('/var/lib/dhcp/dhcpd.leases', 'r')
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leases = parse_leases_file(myfile)
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myfile.close()
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now = timestamp_now()
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report_dataset = select_active_leases(leases, now)
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print('+------------------------------------------------------------------------------')
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print('| DHCPD ACTIVE LEASES REPORT')
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print('+-----------------+-------------------+----------------------+-----------------')
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print('| IP Address | MAC Address | Expires (days,H:M:S) | Client Hostname ')
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print('+-----------------+-------------------+----------------------+-----------------')
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for lease in report_dataset:
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print('| ' + format(lease['ip_address'], '<15') + ' | ' + \
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format(lease['hardware'], '<17') + ' | ' + \
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format(str((lease['ends'] - now) if lease['ends'] != 'never' else 'never'), '>20') + ' | ' + \
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lease['client-hostname'])
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print('+-----------------+-------------------+----------------------+-----------------')
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print('| Total Active Leases: ' + str(len(report_dataset)))
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print('| Report generated (UTC): ' + str(now))
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print('+------------------------------------------------------------------------------')
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