|
| 1 | +#!/usr/bin/python |
| 2 | +import datetime, bisect |
| 3 | + |
| 4 | +def parse_timestamp(raw_str): |
| 5 | + tokens = raw_str.split() |
| 6 | + |
| 7 | + if len(tokens) == 1: |
| 8 | + if tokens[0].lower() == 'never': |
| 9 | + return 'never'; |
| 10 | + |
| 11 | + else: |
| 12 | + raise Exception('Parse error in timestamp') |
| 13 | + |
| 14 | + elif len(tokens) == 3: |
| 15 | + return datetime.datetime.strptime(' '.join(tokens[1:]), |
| 16 | + '%Y/%m/%d %H:%M:%S') |
| 17 | + |
| 18 | + else: |
| 19 | + raise Exception('Parse error in timestamp') |
| 20 | + |
| 21 | + |
| 22 | +def timestamp_is_ge(t1, t2): |
| 23 | + if t1 == 'never': |
| 24 | + return True |
| 25 | + |
| 26 | + elif t2 == 'never': |
| 27 | + return False |
| 28 | + |
| 29 | + else: |
| 30 | + return t1 >= t2 |
| 31 | + |
| 32 | + |
| 33 | +def timestamp_is_lt(t1, t2): |
| 34 | + if t1 == 'never': |
| 35 | + return False |
| 36 | + |
| 37 | + elif t2 == 'never': |
| 38 | + return t1 != 'never' |
| 39 | + |
| 40 | + else: |
| 41 | + return t1 < t2 |
| 42 | + |
| 43 | + |
| 44 | +def timestamp_is_between(t, tstart, tend): |
| 45 | + return timestamp_is_ge(t, tstart) and timestamp_is_lt(t, tend) |
| 46 | + |
| 47 | + |
| 48 | +def parse_hardware(raw_str): |
| 49 | + tokens = raw_str.split() |
| 50 | + |
| 51 | + if len(tokens) == 2: |
| 52 | + return tokens[1] |
| 53 | + |
| 54 | + else: |
| 55 | + raise Exception('Parse error in hardware') |
| 56 | + |
| 57 | + |
| 58 | +def strip_endquotes(raw_str): |
| 59 | + return raw_str.strip('"') |
| 60 | + |
| 61 | + |
| 62 | +def identity(raw_str): |
| 63 | + return raw_str |
| 64 | + |
| 65 | + |
| 66 | +def parse_binding_state(raw_str): |
| 67 | + tokens = raw_str.split() |
| 68 | + |
| 69 | + if len(tokens) == 2: |
| 70 | + return tokens[1] |
| 71 | + |
| 72 | + else: |
| 73 | + raise Exception('Parse error in binding state') |
| 74 | + |
| 75 | + |
| 76 | +def parse_next_binding_state(raw_str): |
| 77 | + tokens = raw_str.split() |
| 78 | + |
| 79 | + if len(tokens) == 3: |
| 80 | + return tokens[2] |
| 81 | + |
| 82 | + else: |
| 83 | + raise Exception('Parse error in next binding state') |
| 84 | + |
| 85 | + |
| 86 | +def parse_rewind_binding_state(raw_str): |
| 87 | + tokens = raw_str.split() |
| 88 | + |
| 89 | + if len(tokens) == 3: |
| 90 | + return tokens[2] |
| 91 | + |
| 92 | + else: |
| 93 | + raise Exception('Parse error in next binding state') |
| 94 | + |
| 95 | + |
| 96 | +def parse_leases_file(leases_file): |
| 97 | + valid_keys = { |
| 98 | + 'starts': parse_timestamp, |
| 99 | + 'ends': parse_timestamp, |
| 100 | + 'tstp': parse_timestamp, |
| 101 | + 'tsfp': parse_timestamp, |
| 102 | + 'atsfp': parse_timestamp, |
| 103 | + 'cltt': parse_timestamp, |
| 104 | + 'hardware': parse_hardware, |
| 105 | + 'binding': parse_binding_state, |
| 106 | + 'next': parse_next_binding_state, |
| 107 | + 'rewind': parse_rewind_binding_state, |
| 108 | + 'uid': strip_endquotes, |
| 109 | + 'client-hostname': strip_endquotes, |
| 110 | + 'option': identity, |
| 111 | + 'set': identity, |
| 112 | + 'on': identity, |
| 113 | + 'abandoned': None, |
| 114 | + 'bootp': None, |
| 115 | + 'reserved': None, |
| 116 | + } |
| 117 | + |
| 118 | + leases_db = {} |
| 119 | + |
| 120 | + lease_rec = {} |
| 121 | + in_lease = False |
| 122 | + in_failover = False |
| 123 | + |
| 124 | + for line in leases_file: |
| 125 | + if line.lstrip().startswith('#'): |
| 126 | + continue |
| 127 | + |
| 128 | + tokens = line.split() |
| 129 | + |
| 130 | + if len(tokens) == 0: |
| 131 | + continue |
| 132 | + |
| 133 | + key = tokens[0].lower() |
| 134 | + |
| 135 | + if key == 'lease': |
| 136 | + if not in_lease: |
| 137 | + ip_address = tokens[1] |
| 138 | + |
| 139 | + lease_rec = {'ip_address' : ip_address} |
| 140 | + in_lease = True |
| 141 | + |
| 142 | + else: |
| 143 | + raise Exception('Parse error in leases file') |
| 144 | + |
| 145 | + elif key == 'failover': |
| 146 | + in_failover = True |
| 147 | + elif key == '}': |
| 148 | + if in_lease: |
| 149 | + for k in valid_keys: |
| 150 | + if callable(valid_keys[k]): |
| 151 | + lease_rec[k] = lease_rec.get(k, '') |
| 152 | + else: |
| 153 | + lease_rec[k] = False |
| 154 | + |
| 155 | + ip_address = lease_rec['ip_address'] |
| 156 | + |
| 157 | + if ip_address in leases_db: |
| 158 | + leases_db[ip_address].insert(0, lease_rec) |
| 159 | + |
| 160 | + else: |
| 161 | + leases_db[ip_address] = [lease_rec] |
| 162 | + |
| 163 | + lease_rec = {} |
| 164 | + in_lease = False |
| 165 | + |
| 166 | + elif in_failover: |
| 167 | + in_failover = False |
| 168 | + continue |
| 169 | + else: |
| 170 | + raise Exception('Parse error in leases file') |
| 171 | + |
| 172 | + elif key in valid_keys: |
| 173 | + if in_lease: |
| 174 | + value = line[(line.index(key) + len(key)):] |
| 175 | + value = value.strip().rstrip(';').rstrip() |
| 176 | + |
| 177 | + if callable(valid_keys[key]): |
| 178 | + lease_rec[key] = valid_keys[key](value) |
| 179 | + else: |
| 180 | + lease_rec[key] = True |
| 181 | + |
| 182 | + else: |
| 183 | + raise Exception('Parse error in leases file') |
| 184 | + |
| 185 | + else: |
| 186 | + if in_lease: |
| 187 | + raise Exception('Parse error in leases file') |
| 188 | + |
| 189 | + if in_lease: |
| 190 | + raise Exception('Parse error in leases file') |
| 191 | + |
| 192 | + return leases_db |
| 193 | + |
| 194 | + |
| 195 | +def round_timedelta(tdelta): |
| 196 | + return datetime.timedelta(tdelta.days, |
| 197 | + tdelta.seconds + (0 if tdelta.microseconds < 500000 else 1)) |
| 198 | + |
| 199 | + |
| 200 | +def timestamp_now(): |
| 201 | + n = datetime.datetime.utcnow() |
| 202 | + return datetime.datetime(n.year, n.month, n.day, n.hour, n.minute, |
| 203 | + n.second + (0 if n.microsecond < 500000 else 1)) |
| 204 | + |
| 205 | + |
| 206 | +def lease_is_active(lease_rec, as_of_ts): |
| 207 | + return timestamp_is_between(as_of_ts, lease_rec['starts'], |
| 208 | + lease_rec['ends']) |
| 209 | + |
| 210 | + |
| 211 | +def ipv4_to_int(ipv4_addr): |
| 212 | + parts = ipv4_addr.split('.') |
| 213 | + return (int(parts[0]) << 24) + (int(parts[1]) << 16) + \ |
| 214 | + (int(parts[2]) << 8) + int(parts[3]) |
| 215 | + |
| 216 | + |
| 217 | +def select_active_leases(leases_db, as_of_ts): |
| 218 | + retarray = [] |
| 219 | + sortedarray = [] |
| 220 | + |
| 221 | + for ip_address in leases_db: |
| 222 | + lease_rec = leases_db[ip_address][0] |
| 223 | + |
| 224 | + if lease_is_active(lease_rec, as_of_ts): |
| 225 | + ip_as_int = ipv4_to_int(ip_address) |
| 226 | + insertpos = bisect.bisect(sortedarray, ip_as_int) |
| 227 | + sortedarray.insert(insertpos, ip_as_int) |
| 228 | + retarray.insert(insertpos, lease_rec) |
| 229 | + |
| 230 | + return retarray |
| 231 | + |
| 232 | + |
| 233 | +############################################################################## |
| 234 | + |
| 235 | + |
| 236 | +myfile = open('/var/lib/dhcp/dhcpd.leases', 'r') |
| 237 | +leases = parse_leases_file(myfile) |
| 238 | +myfile.close() |
| 239 | + |
| 240 | +now = timestamp_now() |
| 241 | +report_dataset = select_active_leases(leases, now) |
| 242 | + |
| 243 | +print('+-----------------------------------------------------------------------------------------------') |
| 244 | +print('| DHCPD ACTIVE LEASES REPORT') |
| 245 | +print('+-----------------+-------------------+----------------------+----------------------------------') |
| 246 | +print('| IP Address | MAC Address | Expires (days,H:M:S) | Client Hostname ') |
| 247 | +print('+-----------------+-------------------+----------------------+----------------------------------') |
| 248 | + |
| 249 | +for lease in report_dataset: |
| 250 | + print('| ' + format(lease['ip_address'], '<15') + ' | ' + \ |
| 251 | + format(lease['hardware'], '<17') + ' | ' + \ |
| 252 | + format(str((lease['ends'] - now) if lease['ends'] != 'never' else 'never'), '>20') + ' | ' + \ |
| 253 | + lease['client-hostname']) |
| 254 | + |
| 255 | +print('+-----------------+-------------------+----------------------+----------------------------------') |
| 256 | +print('| Total Active Leases: ' + str(len(report_dataset))) |
| 257 | +print('| Report generated (UTC): ' + str(now)) |
| 258 | +print('+-----------------------------------------------------------------------------------------------') |
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