jared
/
leases
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
Browse Source

initial commit, source from a stackoverflow post

master
Jared Dunbar 4 years ago
commit
f6ab9a6236
Signed by: jared GPG Key ID: CF202CC859BAC692
2 changed files with 204 additions and 0 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 203
      leases.py
  2. 1
      src.loc

203
leases.py
View File

@ -0,0 +1,203 @@
#!/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('+------------------------------------------------------------------------------')

1
src.loc
View File

@ -0,0 +1 @@
https://askubuntu.com/questions/219609/how-do-i-show-active-dhcp-leases
Write Preview
Loading…
Cancel
Save