File: command.py

package info (click to toggle)
python-pyghmi 1.6.2-2
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 1,376 kB
  • sloc: python: 21,736; sh: 35; makefile: 18
file content (2313 lines) | stat: -rw-r--r-- 90,945 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
# Copyright 2013 IBM Corporation
# Copyright 2015-2017 Lenovo
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""This represents the low layer message framing portion of IPMI"""

from itertools import chain
import os
import socket
import struct
import threading

import pyghmi.constants as const
import pyghmi.exceptions as exc
import pyghmi.ipmi.events as sel
import pyghmi.ipmi.fru as fru
import pyghmi.ipmi.oem.generic as genericoem
from pyghmi.ipmi.oem.lookup import get_oem_handler
import pyghmi.ipmi.private.util as util
from pyghmi.ipmi import sdr


try:
    from pyghmi.ipmi.private import session
except ImportError:
    session = None
try:
    from pyghmi.ipmi.private import localsession
except ImportError:
    localsession = None

try:
    range = xrange
except NameError:
    pass
try:
    buffer
except NameError:
    buffer = memoryview

boot_devices = {
    'net': 4,
    'network': 4,
    'pxe': 4,
    'hd': 8,
    'safe': 0xc,
    'cd': 0x14,
    'cdrom': 0x14,
    'optical': 0x14,
    'dvd': 0x14,
    'floppy': 0x3c,
    'usb': 0x3c,
    'default': 0x0,
    'setup': 0x18,
    'bios': 0x18,
    'f1': 0x18,
    1: 'network',
    2: 'hd',
    3: 'safe',
    5: 'optical',
    6: 'setup',
    15: 'floppy',
    0: 'default'
}

power_states = {
    "off": 0,
    "on": 1,
    "reset": 3,
    "diag": 4,
    "softoff": 5,
    "shutdown": 5,
    # NOTE(jbjohnso): -1 is not a valid direct boot state,
    #                 but here for convenience of 'in' statement
    "boot": -1,
}


def select_simplesession():
    global session
    import pyghmi.ipmi.private.simplesession as session


def _mask_to_cidr(mask):
    maskn = struct.unpack_from('>I', mask)[0]
    cidr = 32
    while maskn & 0b1 == 0 and cidr > 0:
        cidr -= 1
        maskn >>= 1
    return cidr


def _cidr_to_mask(prefix):
    return struct.pack('>I', 2 ** prefix - 1 << (32 - prefix))


class Housekeeper(threading.Thread):
    """A Maintenance thread for housekeeping

    Long lived use of pyghmi may warrant some recurring asynchronous behavior.
    This stock thread provides a simple minimal context for these housekeeping
    tasks to run in.  To use, do 'pyghmi.ipmi.command.Maintenance().start()'
    and from that point forward, pyghmi should execute any needed ongoing
    tasks automatically as needed.  This is an alternative to calling
    wait_for_rsp or eventloop in a thread of the callers design.
    """

    def run(self):
        Command.eventloop()


class Command(object):
    """Send IPMI commands to BMCs.

    This object represents a persistent session to an IPMI device (bmc) and
    allows the caller to reuse a single session to issue multiple commands.
    This class can be used in a synchronous (wait for answer and return) or
    asynchronous fashion (return immediately and provide responses by
    callbacks).  Synchronous mode is the default behavior.

    For asynchronous mode, simply pass in a callback function.  It is
    recommended to pass in an instance method to callback and ignore the
    callback_args parameter. However, callback_args can optionally be populated
    if desired.

    :param bmc: hostname or ip address of the BMC (default is local)
    :param userid: username to use to connect (default to no user)
    :param password: password to connect to the BMC (defaults to no password)
    :param onlogon: function to run when logon completes in an asynchronous
                    fashion.  This will result in a greenthread behavior.
    :param kg: Optional parameter to use if BMC has a particular Kg configured
    :param verifycallback: For OEM extensions that use HTTPS, this function
                           will be used to evaluate the certificate.
    :param keepalive: If False, then an idle connection will logout rather
                      than keepalive unless held open by console or ongoing
                      activity.
    """

    def __init__(self, bmc=None, userid=None, password=None, port=623,
                 onlogon=None, kg=None, privlevel=None, verifycallback=None,
                 keepalive=True, **kwargs):
        # TODO(jbjohnso): accept tuples and lists of each parameter for mass
        # operations without pushing the async complexities up the stack
        self.onlogon = onlogon
        self.bmc = bmc
        self._sdrcachedir = None
        self._sdr = None
        self._oem = None
        self._oemknown = False
        self._netchannel = None
        self._ipv6support = None
        self.certverify = verifycallback
        self.kwargs = kwargs
        if bmc is None:
            self.ipmi_session = localsession.Session()
        elif onlogon is not None:
            self.ipmi_session = session.Session(bmc=bmc,
                                                userid=userid,
                                                password=password,
                                                onlogon=self.logged,
                                                port=port,
                                                kg=kg,
                                                privlevel=privlevel,
                                                keepalive=keepalive)
            # induce one iteration of the loop, now that we would be
            # prepared for it in theory
            session.Session.wait_for_rsp(0)
        else:
            self.ipmi_session = session.Session(bmc=bmc,
                                                userid=userid,
                                                password=password,
                                                port=port,
                                                kg=kg,
                                                privlevel=privlevel)

    def set_sdr_cachedir(self, path):
        """Register use of a directory for SDR cache.

        Takes the given directory and uses it to persist SDR cache run to run.
        This can greatly improve performance across runs.

        :param path:
        :return:
        """
        self._sdrcachedir = path

    def register_key_handler(self, callback, type='tls'):
        """Assign a verification handler for a public key

        When the library attempts to communicate with the management target
        using a non-IPMI protocol, it will try to verify a key.  This
        allows a caller to register a key handler for accepting or rejecting
        a public key/certificate.  The callback will be passed the peer public
        key or certificate.

        :param callback:  The function to call with public key/certificate
        :param type: Whether the callback is meant to handle 'tls' or 'ssh',
                     defaults to 'tls'
        """
        if type == 'tls':
            self.certverify = callback

    def logged(self, response):
        self.onlogon(response, self)
        self.onlogon = None

    @classmethod
    def eventloop(cls):
        while True:
            session.Session.wait_for_rsp()

    @classmethod
    def wait_for_rsp(cls, timeout):
        """Delay for no longer than timeout for next response.

        This acts like a sleep that exits on activity.

        :param timeout: Maximum number of seconds before returning
        """
        return session.Session.wait_for_rsp(timeout=timeout)

    def _get_device_id(self):
        response = self.raw_command(netfn=0x06, command=0x01)
        if 'error' in response:
            raise exc.IpmiException(response['error'], code=response['code'])
        return {
            'device_id': response['data'][0],
            'device_revision': response['data'][1] & 0b1111,
            'manufacturer_id': struct.unpack(
                '<I', struct.pack('3B', *response['data'][6:9]) + b'\x00')[0],
            'product_id': struct.unpack(
                '<H', struct.pack('2B', *response['data'][9:11]))[0],
            'firmware_version': '{0}.{1}{2}'.format(
                response['data'][2] & 0b1111111,
                response['data'][3] >> 4 & 0b1111,
                response['data'][3] & 0b1111)
        }

    def oem_init(self):
        """Initialize the command object for OEM capabilities

        A number of capabilities are either totally OEM defined or
        else augmented somehow by knowledge of the OEM.  This
        method does an interrogation to identify the OEM.

        """
        if self._oemknown:
            return
        if self.bmc is None:
            self._oem = genericoem.OEMHandler(None, None)
            self._oemknown = True
            return
        self._oem, self._oemknown = get_oem_handler(self._get_device_id(),
                                                    self)

    def get_bootdev(self):
        """Get current boot device override information.

        Provides the current requested boot device.  Be aware that not all IPMI
        devices support this.  Even in BMCs that claim to, occasionally the
        BIOS or UEFI fail to honor it. This is usually only applicable to the
        next reboot.

        :raises: IpmiException on an error.
        :returns: dict --The response will be provided in the return as a dict
        """
        response = self.raw_command(netfn=0, command=9, data=(5, 0, 0))
        # interpret response per 'get system boot options'
        if 'error' in response:
            raise exc.IpmiException(response['error'])
        # this should only be invoked for get system boot option complying to
        # ipmi spec and targeting the 'boot flags' parameter
        assert (response['command'] == 9
                and response['netfn'] == 1
                and response['data'][0] == 1
                and (response['data'][1] & 0b1111111) == 5)
        if (response['data'][1] & 0b10000000
                or not response['data'][2] & 0b10000000):
            return {'bootdev': 'default', 'persistent': True}
        else:  # will consult data2 of the boot flags parameter for the data
            persistent = False
            uefimode = False
            if response['data'][2] & 0b1000000:
                persistent = True
            if response['data'][2] & 0b100000:
                uefimode = True
            bootnum = (response['data'][3] & 0b111100) >> 2
            bootdev = boot_devices.get(bootnum)
            if bootdev:
                return {'bootdev': bootdev,
                        'persistent': persistent,
                        'uefimode': uefimode}
            else:
                return {'bootdev': bootnum,
                        'persistent': persistent,
                        'uefimode': uefimode}

    def reseat_bay(self, bay):
        """Request the reseat of a bay

        Request the enclosure manager to reseat the system in a particular
        bay.

        :param bay: The bay identifier to reseat
        :return:
        """
        self.oem_init()
        self._oem.reseat_bay(bay)

    def set_power(self, powerstate, wait=False, bridge_request=None):
        """Request power state change (helper)

        :param powerstate:
                            * on -- Request system turn on
                            * off -- Request system turn off without waiting
                                     for OS to shutdown
                            * shutdown -- Have system request OS proper
                                          shutdown
                            * reset -- Request system reset without waiting for
                              OS
                            * boot -- If system is off, then 'on', else 'reset'
        :param wait: If True, do not return until system actually completes
                     requested state change for 300 seconds.
                     If a non-zero number, adjust the wait time to the
                     requested number of seconds
        :param bridge_request: The target slave address and channel number for
                               the bridge request.
        :raises: IpmiException on an error
        :returns: dict -- A dict describing the response retrieved
        """
        self.oem_init()

        if hasattr(self._oem, 'set_power'):
            return self._oem.set_power(powerstate,
                                       bridge_request=bridge_request)

        if hasattr(self._oem, 'process_power_state'):
            powerstate = self._oem.process_power_state(
                powerstate, bridge_request=bridge_request)

        if powerstate not in power_states:
            raise exc.InvalidParameterValue(
                "Unknown power state %s requested" % powerstate)
        newpowerstate = powerstate
        oldpowerstate = self._get_power_state(bridge_request=bridge_request)
        if oldpowerstate == newpowerstate:
            return {'powerstate': oldpowerstate}
        if newpowerstate == 'boot':
            newpowerstate = 'on' if oldpowerstate == 'off' else 'reset'
        response = self.raw_command(
            netfn=0, command=2, data=[power_states[newpowerstate]],
            bridge_request=bridge_request)
        if 'error' in response:
            raise exc.IpmiException(response['error'])
        lastresponse = {'pendingpowerstate': newpowerstate}
        waitattempts = 300
        if not isinstance(wait, bool):
            waitattempts = wait
        if wait and newpowerstate in ('on', 'off', 'shutdown', 'softoff'):
            if newpowerstate in ('softoff', 'shutdown'):
                waitpowerstate = 'off'
            else:
                waitpowerstate = newpowerstate
            currpowerstate = None
            while currpowerstate != waitpowerstate and waitattempts > 0:
                currpowerstate = self._get_power_state(
                    delay_xmit=1,
                    bridge_request=bridge_request)
                waitattempts -= 1
            if currpowerstate != waitpowerstate:
                raise exc.IpmiException(
                    "System did not accomplish power state change")
            return {'powerstate': currpowerstate}
        else:
            return lastresponse

    def _get_power_state(self, delay_xmit=None, bridge_request=None):
        response = self.raw_command(netfn=0, command=1, delay_xmit=delay_xmit,
                                    bridge_request=bridge_request)
        if 'error' in response:
            raise exc.IpmiException(response['error'])
        assert (response['command'] == 1 and response['netfn'] == 1)
        curr_power_state = 'on' if (response['data'][0] & 1) else 'off'

        return curr_power_state

    def get_video_launchdata(self):
        """Get data required to launch a remote video session to target.

        This is a highly proprietary scenario, the return data may vary greatly
        host to host.  The return should be a dict describing the type of data
        and the data.  For example {'jnlp': jnlpstring}
        """
        self.oem_init()
        return self._oem.get_video_launchdata()

    def reset_bmc(self):
        """Do a cold reset in BMC"""
        response = self.raw_command(netfn=6, command=2, retry=False)
        if response and 'error' in response:
            raise exc.IpmiException(response['error'])

    def set_bootdev(self,
                    bootdev,
                    persist=False,
                    uefiboot=False):
        """Set boot device to use on next reboot (helper)

        :param bootdev:
                        *network -- Request network boot
                        *hd -- Boot from hard drive
                        *safe -- Boot from hard drive, requesting 'safe mode'
                        *optical -- boot from CD/DVD/BD drive
                        *setup -- Boot into setup utility
                        *default -- remove any IPMI directed boot device
                                    request
        :param persist: If true, ask that system firmware use this device
                        beyond next boot.  Be aware many systems do not honor
                        this
        :param uefiboot: If true, request UEFI boot explicitly.  Strictly
                         speaking, the spec sugests that if not set, the system
                         should BIOS boot and offers no "don't care" option.
                         In practice, this flag not being set does not preclude
                         UEFI boot on any system I've encountered.
        :raises: IpmiException on an error.
        :returns: dict or True -- If callback is not provided, the response
        """
        if bootdev not in boot_devices:
            return {'error': "Unknown bootdevice %s requested" % bootdev}
        bootdevnum = boot_devices[bootdev]
        # first, we disable timer by way of set system boot options,
        # then move on to set chassis capabilities
        # Set System Boot Options is netfn=0, command=8, data
        response = self.raw_command(netfn=0, command=8, data=(3, 8))
        if 'error' in response:
            raise exc.IpmiException(response['error'])
        bootflags = 0x80
        if uefiboot:
            bootflags |= 1 << 5
        if persist:
            bootflags |= 1 << 6
        if bootdevnum == 0:
            bootflags = 0
        data = (5, bootflags, bootdevnum, 0, 0, 0)
        response = self.raw_command(netfn=0, command=8, data=data)
        if 'error' in response:
            raise exc.IpmiException(response['error'])
        return {'bootdev': bootdev}

    def xraw_command(self, netfn, command, bridge_request=(), data=(),
                     delay_xmit=None, retry=True, timeout=None, rslun=0):
        """Send raw ipmi command to BMC, raising exception on error

        This is identical to raw_command, except it raises exceptions
        on IPMI errors and returns data as a buffer.  This is the recommend
        function to use.  The response['data'] being a buffer allows
        traditional indexed access as well as works nicely with
        struct.unpack_from when certain data is coming back.

        :param netfn: Net function number
        :param command: Command value
        :param bridge_request: The target slave address and channel number for
                               the bridge request.
        :param data: Command data as a tuple or list
        :param retry: Whether to retry this particular payload or not, defaults
                      to true.
        :param timeout: A custom time to wait for initial reply, useful for
                        a slow command.  This may interfere with retry logic.
        :returns: dict -- The response from IPMI device
        """
        rsp = self.ipmi_session.raw_command(netfn=netfn, command=command,
                                            bridge_request=bridge_request,
                                            data=data, delay_xmit=delay_xmit,
                                            retry=retry, timeout=timeout,
                                            rslun=rslun)
        if 'error' in rsp:
            raise exc.IpmiException(rsp['error'], rsp['code'])
        rsp['data'] = buffer(rsp['data'])
        return rsp

    def get_diagnostic_data(self, savefile, progress=None, autosuffix=False):
        if os.path.exists(savefile) and not os.path.isdir(savefile):
            raise exc.InvalidParameterValue(
                'Not allowed to overwrite existing file: {0}'.format(
                    savefile))
        self.oem_init()
        return self._oem.get_diagnostic_data(savefile, progress, autosuffix)

    def get_description(self):
        """Get physical attributes for the system, e.g. for GUI use

        :returns: dict -- dict containing attributes, 'height' is for
               how many U tall, 'slot' for what slot in a blade enclosure
               or 0 if not blade, for example.
        """
        self.oem_init()
        return self._oem.get_description()

    def raw_command(self, netfn, command, bridge_request=(), data=(),
                    delay_xmit=None, retry=True, timeout=None, rslun=0):
        """Send raw ipmi command to BMC

        This allows arbitrary IPMI bytes to be issued.  This is commonly used
        for certain vendor specific commands.

        Example: ipmicmd.raw_command(netfn=0,command=4,data=(5))

        :param netfn: Net function number
        :param command: Command value
        :param bridge_request: The target slave address and channel number for
                               the bridge request.
        :param data: Command data as a tuple or list
        :param retry: Whether or not to retry command if no response received.
                      Defaults to True
        :param timeout: A custom amount of time to wait for initial reply
        :returns: dict -- The response from IPMI device
        """
        rsp = self.ipmi_session.raw_command(netfn=netfn, command=command,
                                            bridge_request=bridge_request,
                                            data=data, delay_xmit=delay_xmit,
                                            retry=retry, timeout=timeout,
                                            rslun=rslun)
        return rsp

    def get_power(self, bridge_request=None):
        """Get current power state of the managed system

        The response, if successful, should contain 'powerstate' key and
        either 'on' or 'off' to indicate current state.

        :param bridge_request: The target slave address and channel number for
                               the bridge request.
        :returns: dict -- {'powerstate': value}
        """
        self.oem_init()
        if hasattr(self._oem, 'get_power'):
            return {'powerstate': self._oem.get_power(
                bridge_request=bridge_request)}

        return {'powerstate': self._get_power_state(
            bridge_request=bridge_request)}

    def set_identify(self, on=True, duration=None, blink=False):
        """Request identify light

        Request the identify light to turn off, on for a duration,
        or on indefinitely.  Other than error exceptions,

        :param on: Set to True to force on or False to force off
        :param duration: Set if wanting to request turn on for a duration
                         rather than indefinitely on
        """
        self.oem_init()
        try:
            self._oem.set_identify(on, duration, blink)
            return
        except exc.BypassGenericBehavior:
            return
        except exc.UnsupportedFunctionality:
            pass
        if blink:
            raise exc.IpmiException('Blink not supported with generic IPMI')
        if duration is not None:
            duration = int(duration)
            if duration > 255:
                duration = 255
            if duration < 0:
                duration = 0
            response = self.raw_command(netfn=0, command=4, data=[duration])
            if 'error' in response:
                raise exc.IpmiException(response['error'])
            return
        forceon = 0
        if on:
            forceon = 1
        if self.ipmi_session.ipmiversion < 2.0:
            # ipmi 1.5 made due with just one byte, make best effort
            # to imitate indefinite as close as possible
            identifydata = [255 * forceon]
        else:
            identifydata = [0, forceon]
        response = self.raw_command(netfn=0, command=4, data=identifydata)
        if 'error' in response:
            raise exc.IpmiException(response['error'])

    def init_sdr(self):
        """Initialize SDR

        Do the appropriate action to have a relevant sensor description
        repository for the current management controller
        """
        # For now, return current sdr if it exists and still connected
        # future, check SDR timestamp for continued relevance
        # further future, optionally support a cache directory/file
        # to store cached copies for given device id, product id, mfg id,
        # sdr timestamp, our data version revision, aux firmware revision,
        # and oem defined field
        self.oem_init()
        if self._sdr is None:
            if hasattr(self._oem, 'init_sdr'):
                self._sdr = self._oem.init_sdr()
            else:
                self._sdr = sdr.SDR(self, self._sdrcachedir)
        return self._sdr

    def get_event_constants(self):
        self.oem_init()
        return self._oem.get_oem_event_const()

    def get_event_log(self, clear=False):
        """Retrieve the log of events, optionally clearing

        The contents of the SEL are returned as an iterable.  Timestamps
        are given as local time, ISO 8601 (whether the target has an accurate
        clock or not).  Timestamps may be omitted for events that cannot be
        given a timestamp, leaving only the raw timecode to provide relative
        time information.  clear set to true will result in the log being
        cleared as it is returned.  This allows an atomic fetch and clear
        behavior so that no log entries will be lost between the fetch and
        clear actions.  There is no 'clear_event_log' function to encourage
        users to create code that is not at risk for losing events.

        :param clear:  Whether to remove the SEL entries from the target BMC
        """
        self.oem_init()
        return sel.EventHandler(self.init_sdr(), self).fetch_sel(self, clear)

    def decode_pet(self, specifictrap, petdata):
        """Decode PET to an event

        In IPMI, the alert format are PET alerts.  It is a particular set of
        data put into an SNMPv1 trap and sent. It bears no small resemblence
        to the SEL entries.  This function takes data that would have been
        received by an SNMP trap handler, and provides an event decode, similar
        to one entry of get_event_log.

        :param specifictrap: The specific trap, as either a bytearray or int
        :param petdata: An iterable of the octet data of varbind for
                        1.3.6.1.4.1.3183.1.1.1
        :returns: A dict event similar to one iteration of get_event_log
        """
        self.oem_init()
        return sel.EventHandler(self.init_sdr(), self).decode_pet(specifictrap,
                                                                  petdata)

    def get_ikvm_methods(self):
        self.oem_init()
        return self._oem.get_ikvm_methods()

    def get_ikvm_launchdata(self):
        self.oem_init()
        return self._oem.get_ikvm_launchdata()

    def get_inventory_descriptions(self):
        """Retrieve list of things that could be inventoried

        This permits a caller to examine the available items
        without actually causing the inventory data to be gathered.  It
        returns an iterable of string descriptions
        """
        yield "System"
        self.init_sdr()
        for fruid in sorted(self._sdr.fru):
            yield self._sdr.fru[fruid].fru_name
        self.oem_init()
        for compname in self._oem.get_oem_inventory_descriptions():
            yield compname

    def get_inventory_of_component(self, component):
        """Retrieve inventory of a component

        Retrieve detailed inventory information for only the requested
        component.
        """
        self.oem_init()
        if component == 'System':
            return self._get_zero_fru()
        self.init_sdr()
        for fruid in self._sdr.fru:
            if self._sdr.fru[fruid].fru_name == component:
                return self._oem.process_fru(fru.FRU(
                    ipmicmd=self, fruid=fruid,
                    sdr=self._sdr.fru[fruid]).info, component)
        return self._oem.get_inventory_of_component(component)

    def _get_zero_fru(self):
        # Add some fields returned by get device ID command to FRU 0
        # Also rename them to something more in line with FRU 0 field naming
        # standards
        device_id = self._get_device_id()
        device_id['Device ID'] = device_id.pop('device_id')
        device_id['Device Revision'] = device_id.pop('device_revision')
        device_id['Manufacturer ID'] = device_id.pop('manufacturer_id')
        device_id['Product ID'] = device_id.pop('product_id')

        zerofru = fru.FRU(ipmicmd=self).info
        if zerofru is None:
            zerofru = {}
        zerofru.update(device_id)
        zerofru = self._oem.process_zero_fru(zerofru)
        # If uuid is not returned in OEM processing,
        # then it is expected that a manufacturer matches SMBIOS to IPMI
        # get system uuid return data.
        if 'UUID' not in zerofru:
            guiddata = self.raw_command(netfn=6, command=0x37)
            if 'error' not in guiddata:
                zerofru['UUID'] = util.\
                    decode_wireformat_uuid(guiddata['data'])
        return zerofru

    def get_inventory(self):
        """Retrieve inventory of system

        Retrieve inventory of the targeted system.  This frequently includes
        serial numbers, sometimes hardware addresses, sometimes memory modules
        This function will retrieve whatever the underlying platform provides
        and apply some structure.  Iterating over the return yields tuples
        of a name for the inventoried item and dictionary of descriptions
        or None for items not present.
        """
        self.oem_init()
        yield ("System", self._get_zero_fru())
        self.init_sdr()
        for fruid in sorted(self._sdr.fru):
            fruinf = fru.FRU(
                ipmicmd=self, fruid=fruid, sdr=self._sdr.fru[fruid]).info
            if fruinf is not None:
                fruinf = self._oem.process_fru(fruinf,
                                               self._sdr.fru[fruid].fru_name)
            # check the fruinf again as the oem process may return None
            if fruinf:
                yield (self._sdr.fru[fruid].fru_name, fruinf)
        for componentpair in self._oem.get_oem_inventory():
            yield componentpair

    def get_leds(self):
        """Get LED status information

        This provides a detailed view of the LEDs of the managed system.
        """
        self.oem_init()
        return self._oem.get_leds()

    def get_ntp_enabled(self):
        self.oem_init()
        return self._oem.get_ntp_enabled()

    def set_ntp_enabled(self, enable):
        self.oem_init()
        return self._oem.set_ntp_enabled(enable)

    def get_ntp_servers(self):
        self.oem_init()
        return self._oem.get_ntp_servers()

    def set_ntp_server(self, server, index=0):
        self.oem_init()
        return self._oem.set_ntp_server(server, index)

    def get_health(self):
        """Summarize health of managed system

        This provides a summary of the health of the managed system.
        It additionally provides an iterable list of reasons for
        warning, critical, or failed assessments.
        """
        summary = {'badreadings': [], 'health': const.Health.Ok}
        fallbackreadings = []
        try:
            self.oem_init()
            fallbackreadings = self._oem.get_health(summary)
            for reading in self.get_sensor_data():
                if reading.health != const.Health.Ok:
                    summary['health'] |= reading.health
                    summary['badreadings'].append(reading)
        except exc.BypassGenericBehavior:
            pass
        if not summary['badreadings']:
            summary['badreadings'] = fallbackreadings
        return summary

    def get_system_power_watts(self):
        self.oem_init()
        return self._oem.get_system_power_watts(self)
    
    def get_inlet_temperature(self):
        self.oem_init()
        return self._oem.get_inlet_temperature(self)

    def get_average_processor_temperature(self):
        self.oem_init()
        return self._oem.get_average_processor_temperature(self)

    def get_sensor_reading(self, sensorname):
        """Get a sensor reading by name

        Returns a single decoded sensor reading per the name
        passed in

        :param sensorname:  Name of the desired sensor
        :returns: sdr.SensorReading object
        """
        self.init_sdr()
        for sensor in self._sdr.get_sensor_numbers():
            if self._sdr.sensors[sensor].name == sensorname:
                currsensor = self._sdr.sensors[sensor]
                rsp = self.raw_command(command=0x2d, netfn=4,
                                       rslun=currsensor.sensor_lun,
                                       data=(currsensor.sensor_number,))
                if 'error' in rsp:
                    raise exc.IpmiException(rsp['error'], rsp['code'])
                return self._sdr.sensors[sensor].decode_sensor_reading(
                    self, rsp['data'])
        self.oem_init()
        return self._oem.get_sensor_reading(sensorname)

    def _fetch_lancfg_param(self, channel, param, prefixlen=False):
        """Internal helper for fetching lan cfg parameters

        If the parameter revison != 0x11, bail.  Further, if 4 bytes, return
        string with ipv4.  If 6 bytes, colon delimited hex (mac address).  If
        one byte, return the int value
        """
        fetchcmd = bytearray((channel, param, 0, 0))
        try:
            fetched = self.xraw_command(0xc, 2, data=fetchcmd)
        except exc.IpmiException as ie:
            if ie.ipmicode == 0x80:
                return None
            raise
        fetchdata = fetched['data']
        if bytearray(fetchdata)[0] != 17:
            return None
        if len(fetchdata) == 5:  # IPv4 address
            if prefixlen:
                return _mask_to_cidr(fetchdata[1:])
            else:
                ip = socket.inet_ntoa(fetchdata[1:])
                if ip == '0.0.0.0':
                    return None
                return ip
        elif len(fetchdata) == 7:  # MAC address
            mac = '{0:02x}:{1:02x}:{2:02x}:{3:02x}:{4:02x}:{5:02x}'.format(
                *bytearray(fetchdata[1:]))
            if mac == '00:00:00:00:00:00':
                return None
            return mac
        elif len(fetchdata) == 2:
            return bytearray(fetchdata)[1]
        else:
            raise Exception("Unrecognized data format " + repr(fetchdata))

    def get_extended_bmc_configuration(self, hideadvanced=True):
        self.oem_init()
        return self._oem.get_extended_bmc_configuration(hideadvanced=hideadvanced)

    def get_bmc_configuration(self):
        self.oem_init()
        return self._oem.get_bmc_configuration()

    def set_bmc_configuration(self, changeset):
        self.oem_init()
        return self._oem.set_bmc_configuration(changeset)

    def clear_bmc_configuration(self):
        self.oem_init()
        return self._oem.clear_bmc_configuration()

    def get_system_configuration(self, hideadvanced=True):
        self.oem_init()
        return self._oem.get_system_configuration(hideadvanced)

    def set_system_configuration(self, changeset):
        self.oem_init()
        return self._oem.set_system_configuration(changeset)

    def clear_system_configuration(self):
        """Clear the Bios/UEFI configuration

        This requests the system revert to factory default settings
        """
        self.oem_init()
        self._oem.clear_system_configuration()

    def set_net6_configuration(self, static_addresses=None, static_gateway=None, channel=None):
        if static_addresses is None and static_gateway is None:
            return
        if channel is None:
            channel = self.get_network_channel()
        if static_addresses is not None:
            i = 0
            for va in static_addresses:
                if '/' in va:
                    va, plen = va.split('/', 1)
                else:
                    plen = '64'
                plen = int(plen)
                vab = bytearray(socket.inet_pton(socket.AF_INET6, va))
                cmddata = bytearray([channel, 56, 0, 0x80]) + vab + bytearray([plen, 0])
                self.xraw_command(netfn=0xc, command=1, data=cmddata)
        if static_gateway is not None:
            gwb = bytearray(socket.inet_pton(socket.AF_INET6, static_gateway))
            cmddata = bytearray([channel, 65]) + gwb
            self.xraw_command(netfn=0xc, command=1, data=cmddata)
    
    def get_net6_configuration(self, channel=None):
        if channel is None:
            channel = self.get_network_channel()
        retdata = {}
        ip6a = self.xraw_command(netfn=0xc, command=2, data=(channel, 56, 0, 0))
        ip6d = bytearray(ip6a['data'])
        if ip6d[0] != 0x11:
            raise Exception('Unsupported reply')
        if ip6d[2] & 0x80 == 0x80:
            ip6b = ip6d[3:19]
            ip6addr = socket.inet_ntop(socket.AF_INET6, ip6b)
            plen = ip6d[19]
            retdata['static_addrs'] = ['{}/{}'.format(ip6addr, plen)]
        ip6g = self.xraw_command(netfn=0xc, command=2, data=(channel, 65, 0, 0))
        ip6gd = bytearray(ip6g['data'])
        if ip6gd[0] != 0x11:
            raise Exception('Unsupported reply')
        gwa = socket.inet_ntop(socket.AF_INET6, bytes(ip6gd[1:17]))
        retdata['static_gateway'] = gwa
        return retdata

    def set_net_configuration(self, ipv4_address=None, ipv4_configuration=None,
                              ipv4_gateway=None, channel=None):
        """Set network configuration data.

        Apply desired network configuration data, leaving unspecified
        parameters alone.

        :param ipv4_address:  CIDR notation for IP address and netmask
                          Example: '192.168.0.10/16'
        :param ipv4_configuration: Method to use to configure the network.
                        'DHCP' or 'Static'.
        :param ipv4_gateway: IP address of gateway to use.
        :param channel:  LAN channel to configure, defaults to autodetect
        """
        if (ipv4_address is None and ipv4_configuration is None
                and ipv4_gateway is None):
            return
        if channel is None:
            channel = self.get_network_channel()
        if ipv4_configuration is not None:
            cmddata = [channel, 4, 0]
            if ipv4_configuration.lower() == 'dhcp':
                cmddata[-1] = 2
            elif ipv4_configuration.lower() == 'static':
                cmddata[-1] = 1
            else:
                raise Exception('Unrecognized ipv4cfg parameter {0}'.format(
                    ipv4_configuration))
            self.xraw_command(netfn=0xc, command=1, data=cmddata)
        if ipv4_address is not None:
            netmask = None
            if '/' in ipv4_address:
                ipv4_address, prefix = ipv4_address.split('/')
                netmask = _cidr_to_mask(int(prefix))
            cmddata = bytearray((channel, 3)) + socket.inet_aton(ipv4_address)
            self.xraw_command(netfn=0xc, command=1, data=cmddata)
            if netmask is not None:
                cmddata = bytearray((channel, 6)) + netmask
                self.xraw_command(netfn=0xc, command=1, data=cmddata)
        if ipv4_gateway is not None:
            cmddata = bytearray((channel, 12)) + socket.inet_aton(ipv4_gateway)
            self.xraw_command(netfn=0xc, command=1, data=cmddata)

    def get_storage_configuration(self):
        """"Get storage configuration data

        Retrieves the storage configuration from the target.  Data is given
        about disks, pools, and volumes.  When referencing something, use the
        relevant 'cfgpath' attribute to describe it.  It is not guaranteed that
        cfgpath will be consistent version to version, so a lookup is suggested
        in end user applications.

        :return: A pyghmi.storage.ConfigSpec object describing current config
        """
        self.oem_init()
        return self._oem.get_storage_configuration()

    def clear_storage_arrays(self):
        """Remove all array and dependent volumes from the system

        :return:
        """
        self.oem_init()
        self._oem.clear_storage_arrays()

    def remove_storage_configuration(self, cfgspec):
        """Remove specified storage configuration from controller.

        :param cfgspec: A pyghmi.storage.ConfigSpec describing what to remove
        :return:
        """
        self.oem_init()
        return self._oem.remove_storage_configuration(cfgspec)

    def apply_storage_configuration(self, cfgspec=None):
        """Evaluate a configuration for validity

        This will check if configuration is currently available and, if given,
        whether the specified cfgspec can be applied.
        :param cfgspec: A pyghmi.storage.ConfigSpec describing desired oonfig
        :return:
        """
        self.oem_init()
        return self._oem.apply_storage_configuration(cfgspec)

    def check_storage_configuration(self, cfgspec=None):
        """Evaluate a configuration for validity

        This will check if configuration is currently available and, if given,
        whether the specified cfgspec can be applied.
        :param cfgspec: A pyghmi.storage.ConfigSpec describing desired oonfig
        :return:
        """
        self.oem_init()
        return self._oem.check_storage_configuration(cfgspec)

    def get_net_configuration(self, channel=None, gateway_macs=True):
        """Get network configuration data

        Retrieve network configuration from the target

        :param channel: Channel to configure, defaults to None for 'autodetect'
        :param gateway_macs: Whether to retrieve mac addresses for gateways
        :returns: A dictionary of network configuration data
        """
        self.oem_init()

        # support for huawei 2288H server
        if hasattr(self._oem, 'get_oem_net_configuration'):
            return self._oem.get_oem_net_configuration()

        if channel is None:
            channel = self.get_network_channel()
        retdata = {}
        v4addr = self._fetch_lancfg_param(channel, 3)
        if v4addr is None:
            retdata['ipv4_address'] = None
        else:
            v4masklen = self._fetch_lancfg_param(channel, 6, prefixlen=True)
            retdata['ipv4_address'] = '{0}/{1}'.format(v4addr, v4masklen)
        v4cfgmethods = {
            0: 'Unspecified',
            1: 'Static',
            2: 'DHCP',
            3: 'BIOS',
            4: 'Other',
        }
        retdata['ipv4_configuration'] = v4cfgmethods[self._fetch_lancfg_param(
            channel, 4)]
        retdata['mac_address'] = self._fetch_lancfg_param(channel, 5)
        retdata['ipv4_gateway'] = self._fetch_lancfg_param(channel, 12)
        retdata['ipv4_backup_gateway'] = self._fetch_lancfg_param(channel, 14)
        if gateway_macs:
            retdata['ipv4_gateway_mac'] = self._fetch_lancfg_param(channel, 13)
            retdata['ipv4_backup_gateway_mac'] = self._fetch_lancfg_param(
                channel, 15)
        self.oem_init()
        self._oem.add_extra_net_configuration(retdata, channel)
        return retdata

    def get_sensor_data(self):
        """Get sensor reading objects

        Iterates sensor reading objects pertaining to the currently
        managed BMC.

        :returns: Iterator of sdr.SensorReading objects
        """
        self.init_sdr()
        for sensor in self._sdr.get_sensor_numbers():
            currsensor = self._sdr.sensors[sensor]
            rsp = self.raw_command(command=0x2d, netfn=4,
                                   rslun=currsensor.sensor_lun,
                                   data=(currsensor.sensor_number,))
            if 'error' in rsp:
                if rsp['code'] == 203:  # Sensor does not exist, optional dev
                    continue
                raise exc.IpmiException(rsp['error'], code=rsp['code'])
            yield self._sdr.sensors[sensor].\
                decode_sensor_reading(self, rsp['data'])
        self.oem_init()
        for reading in self._oem.get_sensor_data():
            yield reading

    def get_sensor_descriptions(self):
        """Get available sensor names

        Iterates over the available sensor descriptions

        :returns: Iterator of dicts describing each sensor
        """
        self.init_sdr()
        for sensor in self._sdr.get_sensor_numbers():
            yield {'name': self._sdr.sensors[sensor].name,
                   'type': self._sdr.sensors[sensor].sensor_type}
        self.oem_init()
        for sensor in self._oem.get_sensor_descriptions():
            yield sensor

    def get_network_channel(self):
        """Get a reasonable 'default' network channel.

        When configuring/examining network configuration, it's desirable to
        find the correct channel.  Here we run with the 'real' number of the
        current channel if it is a LAN channel, otherwise it evaluates
        all of the channels to find the first workable LAN channel and returns
        that
        """
        if self._netchannel is None:
            for channel in chain((0xe,), range(1, 0xc)):
                try:
                    rsp = self.xraw_command(
                        netfn=6, command=0x42, data=(channel,))
                except exc.IpmiException as ie:
                    if ie.ipmicode == 0xcc:
                        # We have hit an invalid channel, move on to next
                        # candidate
                        continue
                    else:
                        raise
                chantype = bytearray(rsp['data'])[1]
                chantype = chantype & 0b1111111
                if chantype in (4, 6):
                    try:
                        # Some implementations denote an inactive channel
                        # by refusing to do parameter retrieval
                        if channel != 0xe:
                            # skip checking if channel is active if we are
                            # actively using the channel
                            self.xraw_command(
                                netfn=0xc, command=2, data=(channel, 5, 0, 0))
                        # If still here, the channel seems serviceable...
                        # However some implementations may still have
                        # ambiguous channel info, that will need to be
                        # picked up on an OEM extension...
                        netchan = bytearray(rsp['data'])[0]
                        self._netchannel = netchan & 0b1111
                        break
                    except exc.IpmiException:
                        # This means the attempt to fetch parameter 5 failed,
                        # therefore move on to next candidate channel
                        continue
        return self._netchannel

    def get_alert_destination_count(self, channel=None):
        """Get the number of supported alert destinations

        :param channel: Channel for alerts to be examined, defaults to current
        """
        if channel is None:
            channel = self.get_network_channel()
        rqdata = (channel, 0x11, 0, 0)
        rsp = self.xraw_command(netfn=0xc, command=2, data=rqdata)
        self.oem_init()
        if hasattr(self._oem, 'get_alert_destination_count'):
            return self._oem.get_alert_destination_count(ord(rsp['data'][1]))
        return bytearray(rsp['data'])[1]

    def get_alert_destination(self, destination=0, channel=None):
        """Get alert destination

        Get a specified alert destination.  Returns a dictionary of relevant
        configuration.  The following keys may be present:
        acknowledge_required - Indicates whether the target expects an
                               acknowledgement
        acknowledge_timeout - How long it will wait for an acknowledgment
                                  before retrying
        retries - How many attempts will be made to deliver the alert to this
                  destination
        address_format - 'ipv4' or 'ipv6'
        address - The IP address of the target

        :param destination:  The destination number.  Defaults to 0
        :param channel: The channel for alerting.  Defaults to current channel
        """
        self.oem_init()
        if hasattr(self._oem, 'get_alert_destination'):
            return self._oem.get_alert_destination(destination, channel)

        destinfo = {}
        if channel is None:
            channel = self.get_network_channel()
        rqdata = (channel, 18, destination, 0)
        rsp = self.xraw_command(netfn=0xc, command=2, data=rqdata)
        dtype, acktimeout, retries = struct.unpack('BBB', rsp['data'][2:])
        destinfo['acknowledge_required'] = dtype & 0b10000000 == 0b10000000
        # Ignore destination type for now...
        if destinfo['acknowledge_required']:
            destinfo['acknowledge_timeout'] = acktimeout
        destinfo['retries'] = retries
        rqdata = (channel, 19, destination, 0)
        rsp = self.xraw_command(netfn=0xc, command=2, data=rqdata)
        if bytearray(rsp['data'])[2] & 0b11110000 == 0:
            destinfo['address_format'] = 'ipv4'
            destinfo['address'] = socket.inet_ntoa(rsp['data'][4:8])
        elif bytearray(rsp['data'])[2] & 0b11110000 == 0b10000:
            destinfo['address_format'] = 'ipv6'
            destinfo['address'] = socket.inet_ntop(socket.AF_INET6,
                                                   rsp['data'][3:])
        return destinfo

    def clear_alert_destination(self, destination=0, channel=None):
        """Clear an alert destination

        Remove the specified alert destination configuration.

        :param destination:  The destination to clear (defaults to 0)
        """
        if channel is None:
            channel = self.get_network_channel()
        self.set_alert_destination(
            '0.0.0.0', False, 0, 0, destination, channel)

    def set_alert_community(self, community, channel=None):
        """Set the community string for alerts

        This configures the string the BMC will use as the community string
        for PET alerts/traps.

        :param community: The community string
        :param channel: The LAN channel (defaults to auto detect)
        """
        if channel is None:
            channel = self.get_network_channel()
        community = community.encode('utf-8')
        community += b'\x00' * (18 - len(community))
        cmddata = bytearray((channel, 16))
        cmddata += community
        self.xraw_command(netfn=0xc, command=1, data=cmddata)

    def _assure_alert_policy(self, channel, destination):
        """Make sure an alert policy exists

        Each policy will be a dict with the following keys:
        -'index' - The policy index number
        :returns: An iterable of currently configured alert policies
        """
        # First we do a get PEF configuration parameters to get the count
        # of entries.  We have no guarantee that the meaningful data will
        # be contiguous
        rsp = self.xraw_command(netfn=4, command=0x13, data=(8, 0, 0))
        numpol = bytearray(rsp['data'])[1]
        desiredchandest = (channel << 4) | destination
        availpolnum = None
        for polnum in range(1, numpol + 1):
            currpol = self.xraw_command(netfn=4, command=0x13,
                                        data=(9, polnum, 0))
            polidx, chandest = struct.unpack_from('>BB', currpol['data'][2:4])
            if not polidx & 0b1000:
                if availpolnum is None:
                    availpolnum = polnum
                continue
            if chandest == desiredchandest:
                return True
        # If chandest did not equal desiredchandest ever, we need to use a slot
        if availpolnum is None:
            raise Exception("No available alert policy entry")
        # 24 = 1 << 4 | 8
        # 1 == set to which this rule belongs
        # 8 == 0b1000, in other words, enable this policy, always send to
        # indicated destination
        self.xraw_command(netfn=4, command=0x12,
                          data=(9, availpolnum, 24,
                                desiredchandest, 0))

    def get_alert_community(self, channel=None):
        """Get the current community string for alerts

        Returns the community string that will be in SNMP traps from this
        BMC

        :param channel: The channel to get configuration for, autodetect by
                        default
        :returns: The community string
        """
        if channel is None:
            channel = self.get_network_channel()
        rsp = self.xraw_command(netfn=0xc, command=2, data=(channel, 16, 0, 0))
        return rsp['data'][1:].partition('\x00')[0]

    @property
    def _supports_standard_ipv6(self):
        # Supports the *standard* ipv6 commands for various things
        # used to internally steer some commands to standard or OEM
        # handler of commands
        lanchan = self.get_network_channel()
        if self._ipv6support is None:
            rsp = self.raw_command(netfn=0xc, command=0x2, data=(2, lanchan,
                                                                 0x32, 0, 0))
            self._ipv6support = rsp['code'] == 0
        return self._ipv6support

    def set_alert_destination(self, ip=None, acknowledge_required=None,
                              acknowledge_timeout=None, retries=None,
                              destination=0, channel=None):
        """Configure one or more parameters of an alert destination

        If any parameter is 'None' (default), that parameter is left unchanged.
        Otherwise, all given parameters are set by this command.

        :param ip: IP address of the destination.  It is currently expected
                   that the calling code will handle any name lookup and
                   present this data as IP address.
        :param acknowledge_required: Whether or not the target should expect
                                     an acknowledgement from this alert target.
        :param acknowledge_timeout: Time to wait for acknowledgement if enabled
        :param retries:  How many times to attempt transmit of an alert.
        :param destination:  Destination index, defaults to 0.
        :param channel: The channel to configure the alert on.  Defaults to
                current
        """
        self.oem_init()
        if hasattr(self._oem, 'set_alert_destination'):
            self._oem.set_alert_destination(ip)
            return
        if channel is None:
            channel = self.get_network_channel()

        if (acknowledge_required is not None
                or retries is not None
                or acknowledge_timeout is not None):
            currtype = self.xraw_command(netfn=0xc, command=2, data=(
                channel, 18, destination, 0))
            if currtype['data'][0] != b'\x11':
                raise exc.PyghmiException("Unknown parameter format")
            currtype = bytearray(currtype['data'][1:])
            if acknowledge_required is not None:
                if acknowledge_required:
                    currtype[1] |= 0b10000000
                else:
                    currtype[1] &= 0b1111111
            # set PET trap destination
            currtype[1] &= 0b1111000
            if acknowledge_timeout is not None:
                currtype[2] = acknowledge_timeout
            if retries is not None:
                currtype[3] = retries
            destreq = bytearray((channel, 18))
            destreq.extend(currtype)
            self.xraw_command(netfn=0xc, command=1, data=destreq)
        if ip is not None:
            destdata = bytearray((channel, 19, destination))
            try:
                parsedip = socket.inet_pton(socket.AF_INET, ip)
                destdata.extend((0, 0))
                destdata.extend(parsedip)
                destdata.extend('\x00\x00\x00\x00\x00\x00')
            except socket.error:
                parsedip = socket.inet_pton(socket.AF_INET6, ip)
                destdata.append(0b10000000)
                destdata.extend(parsedip)
            self.xraw_command(netfn=0xc, command=1, data=destdata)
        if not ip == '0.0.0.0':
            self._assure_alert_policy(channel, destination)

    def get_hostname(self):
        """Get the hostname used by the BMC in various contexts

        This can vary somewhat in interpretation, but generally speaking
        this should be the name that shows up on UIs and in DHCP requests and
        DNS registration requests, as applicable.

        :return: current hostname
        """
        self.oem_init()
        try:
            return self._oem.get_hostname()
        except exc.UnsupportedFunctionality:
            # Use the DCMI MCI field as a fallback, since it's the closest
            # thing in the IPMI Spec for this
            return self.get_mci()

    def get_mci(self):
        """Set the management controller identifier.

        Try the OEM command first,if False, then set it per DCMI specification

        :returns: The identifier as a string
        """
        self.oem_init()
        identifier = self._oem.get_oem_identifier()
        if identifier:
            return identifier
        return self._chunkwise_dcmi_fetch(9)

    def set_hostname(self, hostname):
        """Set the hostname to be used by the BMC in various contexts.

        See get_hostname for details

        :param hostname: The hostname to set
        :return: Nothing
        """
        self.oem_init()
        try:
            return self._oem.set_hostname(hostname)
        except exc.UnsupportedFunctionality:
            return self.set_mci(hostname)

    def set_mci(self, mci):
        """Set the management controller identifier.

        Try the OEM command first, if False, then set it per DCMI specification
        """
        self.oem_init()
        if not isinstance(mci, bytes):
            mci = mci.encode('utf8')
        ret = self._oem.set_oem_identifier(mci)
        if ret:
            return
        return self._chunkwise_dcmi_set(0xa, mci + b'\x00')

    def get_asset_tag(self):
        """Get the system asset tag, per DCMI specification

        :returns: The asset tag
        """
        self.oem_init()
        if hasattr(self._oem, 'get_asset_tag'):
            return self._oem.get_asset_tag()
        return self._chunkwise_dcmi_fetch(6)

    def set_asset_tag(self, tag):
        """Set the asset tag value

        """
        self.oem_init()
        if hasattr(self._oem, 'set_asset_tag'):
            return self._oem.set_asset_tag(tag)
        return self._chunkwise_dcmi_set(8, tag)

    def _chunkwise_dcmi_fetch(self, command):
        szdata = self.xraw_command(
            netfn=0x2c, command=command, data=(0xdc, 0, 0))
        totalsize = bytearray(szdata['data'])[1]
        chksize = 0xf
        offset = 0
        retstr = b''
        while offset < totalsize:
            if (offset + chksize) > totalsize:
                chksize = totalsize - offset
            chk = self.xraw_command(
                netfn=0x2c, command=command, data=(0xdc, offset, chksize))
            retstr += chk['data'][2:]
            offset += chksize
        if not isinstance(retstr, str):
            retstr = retstr.decode('utf-8')
        return retstr

    def _chunkwise_dcmi_set(self, command, data):
        chunks = [data[i:i + 15] for i in range(0, len(data), 15)]
        offset = 0
        for chunk in chunks:
            chunk = bytearray(chunk)
            cmddata = bytearray((0xdc, offset, len(chunk)))
            cmddata += chunk
            # set offset, otherwise the last setting will override
            # the previous setting
            offset += len(chunk)
            self.xraw_command(netfn=0x2c, command=command, data=cmddata)

    def set_channel_access(self, channel=None,
                           access_update_mode='non_volatile',
                           alerting=False, per_msg_auth=False,
                           user_level_auth=False, access_mode='always',
                           privilege_update_mode='non_volatile',
                           privilege_level='administrator'):
        """Set channel access

        :param channel: number [1:7]

        :param access_update_mode:
            dont_change  = don't set or change Channel Access
            non_volatile = set non-volatile Channel Access
            volatile     = set volatile (active) setting of Channel Access

        :param alerting: PEF Alerting Enable/Disable
        True  = enable PEF Alerting
        False = disable PEF Alerting on this channel
                (Alert Immediate command can still be used to generate alerts)

        :param per_msg_auth: Per-message Authentication
        True  = enable
        False = disable Per-message Authentication. [Authentication required to
                activate any session on this channel, but authentication not
                used on subsequent packets for the session.]

        :param user_level_auth: User Level Authentication Enable/Disable.
        True  = enable User Level Authentication. All User Level commands are
            to be authenticated per the Authentication Type that was
            negotiated when the session was activated.
        False = disable User Level Authentication. Allow User Level commands to
            be executed without being authenticated.
            If the option to disable User Level Command authentication is
            accepted, the BMC will accept packets with Authentication Type
            set to None if they contain user level commands.
            For outgoing packets, the BMC returns responses with the same
            Authentication Type that was used for the request.

        :param access_mode: Access Mode for IPMI messaging
        (PEF Alerting is enabled/disabled separately from IPMI messaging)
        disabled = disabled for IPMI messaging
        pre_boot = pre-boot only channel only available when system is in a
                powered down state or in BIOS prior to start of boot.
        always   = channel always available regardless of system mode.
                BIOS typically dedicates the serial connection to the BMC.
        shared   = same as always available, but BIOS typically leaves the
                serial port available for software use.

        :param privilege_update_mode: Channel Privilege Level Limit.
            This value sets the maximum privilege level
            that can be accepted on the specified channel.
            dont_change  = don't set or change channel Privilege Level Limit
            non_volatile = non-volatile Privilege Level Limit according
            volatile     = volatile setting of Privilege Level Limit

        :param privilege_level: Channel Privilege Level Limit
            * reserved      = unused
            * callback
            * user
            * operator
            * administrator
            * proprietary   = used by OEM
        """
        if channel is None:
            channel = self.get_network_channel()
        data = []
        data.append(channel & 0b00001111)
        access_update_modes = {
            'dont_change': 0,
            'non_volatile': 1,
            'volatile': 2,
            # 'reserved': 3
        }
        b = 0
        b |= (access_update_modes[access_update_mode] << 6) & 0b11000000
        if alerting:
            b |= 0b00100000
        if per_msg_auth:
            b |= 0b00010000
        if user_level_auth:
            b |= 0b00001000
        access_modes = {
            'disabled': 0,
            'pre_boot': 1,
            'always': 2,
            'shared': 3,
        }
        b |= access_modes[access_mode] & 0b00000111
        data.append(b)
        b = 0
        privilege_update_modes = {
            'dont_change': 0,
            'non_volatile': 1,
            'volatile': 2,
            # 'reserved': 3
        }
        b |= (privilege_update_modes[privilege_update_mode] << 6) & 0b11000000
        privilege_levels = {
            'reserved': 0,
            'callback': 1,
            'user': 2,
            'operator': 3,
            'administrator': 4,
            'proprietary': 5,
            # 'no_access': 0x0F,
        }
        b |= privilege_levels[privilege_level] & 0b00000111
        data.append(b)
        response = self.raw_command(netfn=0x06, command=0x40, data=data)
        if 'error' in response:
            raise Exception(response['error'])
        return True

    def get_channel_access(self, channel=None, read_mode='volatile'):
        """Get channel access

        :param channel: number [1:7]
        :param read_mode:
        non_volatile  = get non-volatile Channel Access
        volatile      = get present volatile (active) setting of Channel Access

        :return: A Python dict with the following keys/values:
          {
            - alerting:
            - per_msg_auth:
            - user_level_auth:
            - access_mode:{
                0: 'disabled',
                1: 'pre_boot',
                2: 'always',
                3: 'shared'
              }
            - privilege_level: {
                1: 'callback',
                2: 'user',
                3: 'operator',
                4: 'administrator',
                5: 'proprietary',
              }
           }
        """
        if channel is None:
            channel = self.get_network_channel()
        data = []
        data.append(channel & 0b00001111)
        b = 0
        read_modes = {
            'non_volatile': 1,
            'volatile': 2,
        }
        b |= (read_modes[read_mode] << 6) & 0b11000000
        data.append(b)

        response = self.raw_command(netfn=0x06, command=0x41, data=data)
        if 'error' in response:
            raise Exception(response['error'])

        data = response['data']
        if len(data) != 2:
            raise Exception('expecting 2 data bytes')

        r = {}
        r['alerting'] = data[0] & 0b10000000 > 0
        r['per_msg_auth'] = data[0] & 0b01000000 > 0
        r['user_level_auth'] = data[0] & 0b00100000 > 0
        access_modes = {
            0: 'disabled',
            1: 'pre_boot',
            2: 'always',
            3: 'shared'
        }
        r['access_mode'] = access_modes[data[0] & 0b00000011]
        privilege_levels = {
            0: 'reserved',
            1: 'callback',
            2: 'user',
            3: 'operator',
            4: 'administrator',
            5: 'proprietary',
            # 0x0F: 'no_access'
        }
        r['privilege_level'] = privilege_levels[data[1] & 0b00001111]
        return r

    def get_screenshot(self, outfile):
        self.oem_init()
        return self._oem.get_screenshot(outfile)

    def get_channel_info(self, channel=None):
        """Get channel info

        :param channel: number [1:7]

        :return:
        session_support:
            no_session: channel is session-less
            single: channel is single-session
            multi: channel is multi-session
            auto: channel is session-based (channel could alternate between
                single- and multi-session operation, as can occur with a
                serial/modem channel that supports connection mode auto-detect)
        """
        if channel is None:
            channel = self.get_network_channel()
        data = []
        data.append(channel & 0b00001111)
        response = self.raw_command(netfn=0x06, command=0x42, data=data)
        if 'error' in response:
            raise Exception(response['error'])
        data = response['data']
        if len(data) != 9:
            raise Exception('expecting 10 data bytes got: {0}'.format(data))
        r = {}
        r['Actual channel'] = data[0] & 0b00000111
        channel_medium_types = {
            0: 'reserved',
            1: 'IPMB',
            2: 'ICMB v1.0',
            3: 'ICMB v0.9',
            4: '802.3 LAN',
            5: 'Asynch. Serial/Modem (RS-232)',
            6: 'Other LAN',
            7: 'PCI SMBus',
            8: 'SMBus v1.0/1.1',
            9: 'SMBus v2.0',
            0x0a: 'reserved for USB 1.x',
            0x0b: 'reserved for USB 2.x',
            0x0c: 'System Interface (KCS, SMIC, or BT)',
            # 60h-7Fh: OEM
            # all other  reserved
        }
        t = data[1] & 0b01111111
        if t in channel_medium_types:
            r['Channel Medium type'] = channel_medium_types[t]
        else:
            r['Channel Medium type'] = 'OEM {:02X}'.format(t)
        r['5-bit Channel IPMI Messaging Protocol Type'] = data[2] & 0b00001111
        session_supports = {
            0: 'no_session',
            1: 'single',
            2: 'multi',
            3: 'auto'
        }
        r['session_support'] = session_supports[(data[3] & 0b11000000) >> 6]
        r['active_session_count'] = data[3] & 0b00111111
        r['Vendor ID'] = [data[4], data[5], data[6]]
        r['Auxiliary Channel Info'] = [data[7], data[8]]
        return r

    def set_user_access(self, uid, channel=None, callback=False,
                        link_auth=True, ipmi_msg=True, privilege_level='user'):
        """Set user access

        :param uid: user number [1:16]

        :param channel: number [1:7]

        :param callback: User Restricted to Callback
        False = User Privilege Limit is determined by the User Privilege Limit
            parameter, below, for both callback and non-callback connections.
        True  = User Privilege Limit is determined by the User Privilege Limit
            parameter for callback connections, but is restricted to Callback
            level for non-callback connections. Thus, a user can only initiate
            a Callback when they 'call in' to the BMC, but once the callback
            connection has been made, the user could potentially establish a
            session as an Operator.

        :param link_auth: User Link authentication
        enable/disable (used to enable whether this
        user's name and password information will be used for link
        authentication, e.g. PPP CHAP) for the given channel. Link
        authentication itself is a global setting for the channel and is
        enabled/disabled via the serial/modem configuration parameters.

        :param ipmi_msg: User IPMI Messaginge:
        (used to enable/disable whether
        this user's name and password information will be used for IPMI
        Messaging. In this case, 'IPMI Messaging' refers to the ability to
        execute generic IPMI commands that are not associated with a
        particular payload type. For example, if IPMI Messaging is disabled for
        a user, but that user is enabled for activatallow_authing the SOL
        payload type, then IPMI commands associated with SOL and session
        management, such as Get SOL Configuration Parameters and Close Session
        are available, but generic IPMI commands such as Get SEL Time are
        unavailable.)

        :param privilege_level:
        User Privilege Limit. (Determines the maximum privilege level that the
        user is allowed to switch to on the specified channel.)
            * callback
            * user
            * operator
            * administrator
            * proprietary
            * no_access
            * custom.<name>
        """
        self.oem_init()
        if hasattr(self._oem, 'oem_user_access'):
            callback, privilege_level = self._oem.oem_user_access(
                callback, privilege_level)

        if channel is None:
            channel = self.get_network_channel()
        b = 0b10000000
        if callback:
            b |= 0b01000000
        if link_auth:
            b |= 0b00100000
        if ipmi_msg:
            b |= 0b00010000
        b |= channel & 0b00001111
        privilege_levels = {
            'reserved': 0,
            'callback': 1,
            'user': 2,
            'operator': 3,
            'administrator': 4,
            'proprietary': 5,
            'no_access': 0x0F,
        }
        self.oem_init()
        self._oem.set_user_access(
            uid, channel, callback, link_auth, ipmi_msg, privilege_level)
        if privilege_level.startswith('custom.'):
            return True  # unable to proceed with standard support
        data = [b, uid & 0b00111111,
                privilege_levels[privilege_level] & 0b00001111, 0]
        response = self.raw_command(netfn=0x06, command=0x43, data=data)
        if 'error' in response:
            raise Exception(response['error'])
        # Set KVM and VMedia Allowed if is administrator
        if privilege_level == 'administrator':
            self.set_extended_privilleges(uid)
        return True

    def get_user_access(self, uid, channel=None):
        """Get user access

        :param uid: user number [1:16]
        :param channel: number [1:7]

        :return:
        channel_info:
            max_user_count = maximum number of user IDs on this channel
            enabled_users = count of User ID slots presently in use
            users_with_fixed_names = count of user IDs with fixed names

        access:
            callback
            link_auth
            ipmi_msg
            privilege_level: [reserved, callback, user,
                              operatorm administrator, proprietary, no_access]
        """
        # user access available during call-in or callback direct connection
        if channel is None:
            channel = self.get_network_channel()
        data = [channel, uid]
        response = self.raw_command(netfn=0x06, command=0x44, data=data)
        if 'error' in response:
            raise Exception(response['error'])
        data = response['data']
        if len(data) != 4:
            raise Exception('expecting 4 data bytes')
        r = {'channel_info': {}, 'access': {}}
        r['channel_info']['max_user_count'] = data[0]
        r['channel_info']['enabled_users'] = data[1] & 0b00111111
        r['channel_info']['users_with_fixed_names'] = data[2] & 0b00111111
        r['access']['callback'] = (data[3] & 0b01000000) != 0
        r['access']['link_auth'] = (data[3] & 0b00100000) != 0
        r['access']['ipmi_msg'] = (data[3] & 0b00010000) != 0
        self.oem_init()
        oempriv = self._oem.get_user_privilege_level(uid)
        if oempriv:
            r['access']['privilege_level'] = oempriv
        else:
            privilege_levels = {
                0: 'reserved',
                1: 'callback',
                2: 'user',
                3: 'operator',
                4: 'administrator',
                5: 'proprietary',
                0x0F: 'no_access'
            }
            r['access']['privilege_level'] = privilege_levels[data[3] & 0b00001111]
        return r

    def set_user_name(self, uid, name):
        """Set user name

        :param uid: user number [1:16]
        :param name: username (limit of 16bytes)
        """
        data = [uid]
        if not isinstance(name, bytes):
            name = name.encode('utf-8')
        if len(name) > 16:
            raise Exception('name must be less than or = 16 chars')
        name = name.ljust(16, b'\x00')
        name = bytearray(name)
        data.extend(name)
        # set timeout to 2s to avoid retry causing enable failure
        self.xraw_command(netfn=0x06, command=0x45, data=data, timeout=2)
        return True

    def get_user_name(self, uid, return_none_on_error=True):
        """Get user name

        :param uid: user number [1:16]
        :param return_none_on_error: return None on error
            TODO: investigate return code on error
        """
        response = self.raw_command(netfn=0x06, command=0x46, data=(uid,))
        if 'error' in response:
            if return_none_on_error:
                return None
            raise Exception(response['error'])
        name = None
        if 'data' in response:
            data = response['data']
            if len(data) == 16:
                # convert int array to string
                n = ''.join(chr(data[i]) for i in range(0, len(data)))
                # remove padded \x00 chars
                n = n.rstrip("\x00")
                if len(n) > 0:
                    name = n
        return name

    def set_user_password(self, uid, mode='set_password', password=None):
        """Set user password and (modes)

        :param uid: id number of user.  see: get_names_uid()['name']

        :param mode:
            disable       = disable user connections
            enable        = enable user connections
            set_password  = set or ensure password
            test_password = test password is correct

        :param password: max 16 char string
            (optional when mode is [disable or enable])

        :return:
            True on success
            when mode = test_password, return False on bad password
        """
        mode_mask = {
            'disable': 0,
            'enable': 1,
            'set_password': 2,
            'test_password': 3
        }
        data = [uid, mode_mask[mode]]
        if password:
            if not isinstance(password, bytes):
                password = password.encode('utf8')
            if 21 > len(password) > 16:
                password = password.ljust(20, b'\x00')
                data[0] |= 0b10000000
            elif len(password) > 20:
                raise Exception('password has limit of 20 chars')
            else:
                password = password.ljust(16, b'\x00')
            data.extend(bytearray(password))

        self.oem_init()
        data = self._oem.process_password(password, data)
        try:
            self.xraw_command(netfn=0x06, command=0x47, data=data)
        except exc.IpmiException as ie:
            if mode == 'test_password':
                return False
            elif mode in ('enable', 'disable') and ie.ipmicode == 0xcc:
                # Some BMCs see redundant calls to password disable/enable
                # as invalid
                return True
            raise
        return True

    def get_channel_max_user_count(self, channel=None):
        """Get max users in channel (helper)

        :param channel: number [1:7]
        :return: int -- often 16
        """
        if channel is None:
            channel = self.get_network_channel()
        access = self.get_user_access(channel=channel, uid=1)
        return access['channel_info']['max_user_count']

    def get_user(self, uid, channel=None):
        """Get user (helper)

        :param uid: user number [1:16]
        :param channel: number [1:7]

        :return:
            name: (str)
            uid: (int)
            channel: (int)
            access:
                callback (bool)
                link_auth (bool)
                ipmi_msg (bool)
                privilege_level: (str)[callback, user, operatorm administrator,
                                       proprietary, no_access]
            expiration:
                None for 'unknown', 0 for no expiry, days to expire otherwise.
        """
        if channel is None:
            channel = self.get_network_channel()
        name = self.get_user_name(uid)
        access = self.get_user_access(uid, channel)
        self.oem_init()
        expiration = self._oem.get_user_expiration(uid)
        data = {'name': name, 'uid': uid, 'channel': channel,
                'access': access['access'], 'expiration': expiration}
        return data

    def get_name_uids(self, name, channel=None):
        """get list of users (helper)

        :param channel: number [1:7]

        :return: list of users
        """
        if channel is None:
            channel = self.get_network_channel()
        uid_list = []
        max_ids = self.get_channel_max_user_count(channel)
        for uid in range(1, max_ids):
            if name == self.get_user_name(uid=uid):
                uid_list.append(uid)
        return uid_list

    def get_users(self, channel=None):
        """get list of users and channel access information (helper)

        :param channel: number [1:7]

        :return:
            name: (str)
            uid: (int)
            channel: (int)
            access:
                callback (bool)
                link_auth (bool)
                ipmi_msg (bool)
                privilege_level: (str)[callback, user, operatorm administrator,
                                       proprietary, no_access]
        """
        self.oem_init()
        if channel is None:
            channel = self.get_network_channel()
        names = {}
        max_ids = self.get_channel_max_user_count(channel)
        for uid in range(1, max_ids + 1):
            name = self.get_user_name(uid=uid)
            if self._oem.is_valid(name):
                names[uid] = self.get_user(uid=uid, channel=channel)
        return names

    def create_user(self, uid, name, password, channel=None, callback=False,
                    link_auth=True, ipmi_msg=True,
                    privilege_level='user'):
        """create/ensure a user is created with provided settings (helper)

        :param privilege_level:
            User Privilege Limit. (Determines the maximum privilege level that
            the user is allowed to switch to on the specified channel.)
            * callback
            * user
            * operator
            * administrator
            * proprietary
            * no_access
        """
        # current user might be trying to update.. dont disable
        # set_user_password(uid, password, mode='disable')
        if channel is None:
            channel = self.get_network_channel()
        self.set_user_name(uid, name)
        self.set_user_password(uid, password=password)
        self.set_user_password(uid, mode='enable', password=password)
        self.set_user_access(uid, channel, callback=callback,
                             link_auth=link_auth, ipmi_msg=ipmi_msg,
                             privilege_level=privilege_level)
        return True

    def user_delete(self, uid, channel=None):
        """Delete user (helper)

        Note that in IPMI, user 'deletion' isn't a concept.  This function
        will make a best effort to provide the expected result (e.g.
        web interfaces skipping names and ipmitool skipping as well.

        :param uid: user number [1:16]
        :param channel: number [1:7]
        """
        # TODO(jjohnson2): Provide OEM extensibility to cover user deletion
        self.oem_init()
        if hasattr(self._oem, 'user_delete'):
            try:
                self._oem.user_delete(uid, channel)
            except exc.BypassGenericBehavior:
                return
        if hasattr(self._oem, 'user_delete_privilege_level'):
            privilege_level = self._oem.user_delete_privilege_level()
        else:
            privilege_level = 'no_access'

        if channel is None:
            channel = self.get_network_channel()
        self.set_user_password(uid, mode='disable', password=None)
        # TODO(steveweber) perhaps should set user access on all channels
        # so new users dont get extra access
        self.set_user_access(uid, channel=channel, callback=False,
                             link_auth=False, ipmi_msg=False,
                             privilege_level=privilege_level)
        try:
            # First try to set name to all \x00 explicitly
            # Fix bug-174389, don't try to send \xff command,
            # will cause IMM1 can't login
            self.set_user_name(uid, '')
        except exc.IpmiException:
            raise
        return True

    def disable_user(self, uid, mode):
        """Disable User

        Just disable the User.
        This will not disable the password or revoke privileges.

        :param uid: user number [1:16]
        :param mode:
            disable       = disable user connections
            enable        = enable user connections
        """
        self.set_user_password(uid, mode)
        return True

    def update_user(self, user):
        """Update User

        Update user attributes, include name, password, access

        :param user: user attributes
        """
        if 'username' in user:
            self.set_user_name(uid=user['uid'], name=user['username'])

        privilege_level = None
        if 'privilege_level' in user:
            privilege_level = user['privilege_level']

        if privilege_level and privilege_level == 'no_access':
            return self.upate_user_no_access(user, privilege_level)
        else:
            return self.update_user_default(user, privilege_level)

    def upate_user_no_access(self, user, privilege_level):
        # if set to no_access, modify password first
        if 'password' in user:
            self.set_user_password(uid=user['uid'], password=user['password'])
        self.set_user_access(uid=user['uid'], privilege_level=privilege_level)

        return True

    def update_user_default(self, user, privilege_level):
        if privilege_level:
            self.set_user_access(uid=user['uid'],
                                 privilege_level=privilege_level)
        if 'password' in user:
            self.set_user_password(uid=user['uid'],
                                   password=user['password'])
            self.set_user_password(uid=user['uid'], mode='enable',
                                   password=user['password'])
        if 'enabled' in user:
            if user['enabled'] == 'yes':
                mode = 'enable'
            else:
                mode = 'disable'
            self.disable_user(user['uid'], mode)

        return True

    def get_firmware(self, components=()):
        """Retrieve OEM Firmware information"""

        self.oem_init()
        mcinfo = self.xraw_command(netfn=6, command=1)
        major, minor = struct.unpack('BB', mcinfo['data'][2:4])
        bmcver = '{0}.{1}'.format(major, hex(minor)[2:])
        return self._oem.get_oem_firmware(bmcver, components)

    def get_capping_enabled(self):
        """Get PSU based power capping status

        :return: True if enabled and False if disabled
        """
        self.oem_init()
        return self._oem.get_oem_capping_enabled()

    def set_capping_enabled(self, enable):
        """Set PSU based power capping

        :param enable: True for enable and False for disable
        """
        self.oem_init()
        return self._oem.set_oem_capping_enabled(enable)

    def set_server_capping(self, value):
        self.oem_init()
        self._oem.set_oem_server_capping(value)

    def get_server_capping(self):
        self.oem_init()
        return self._oem.get_oem_server_capping()

    def get_remote_kvm_available(self):
        """Get remote KVM availability"""

        self.oem_init()
        return self._oem.get_oem_remote_kvm_available()

    def get_domain_name(self):
        """Get Domain name"""

        self.oem_init()
        return self._oem.get_oem_domain_name()

    def set_domain_name(self, name):
        """Set Domain name

        :param name: domain name to be set
        """
        self.oem_init()
        self._oem.set_oem_domain_name(name)

    def get_graphical_console(self):
        """Get graphical console launcher"""
        self.oem_init()
        return self._oem.get_graphical_console()

    def get_update_status(self):
        self.oem_init()
        return self._oem.get_update_status()

    def update_firmware(self, filename, data=None, progress=None, bank=None):
        """Send file to BMC to perform firmware update

         :param filename: The filename to upload to the target BMC
         :param data: The payload of the firmware.  Default is to read from
                      specified filename.
         :param progress: A callback that will be given a dict describing
                          update process.  Provide if
         :param bank: Indicate a target 'bank' of firmware if supported
        """

        self.oem_init()
        if progress is None:
            progress = lambda x: True
        return self._oem.update_firmware(filename, data, progress, bank)

    def attach_remote_media(self, url, username=None, password=None):
        """Attach remote media by url

        Given a url, attach remote media (cd/usb image) to the target system.

        :param url:  URL to indicate where to find image (protocol support
                     varies by BMC)
        :param username: Username for endpoint to use when accessing the URL.
                         If applicable, 'domain' would be indicated by '@' or
                         '\' syntax.
        :param password: Password for endpoint to use when accessing the URL.
        """
        self.oem_init()
        return self._oem.attach_remote_media(url, username, password)

    def detach_remote_media(self):
        self.oem_init()
        return self._oem.detach_remote_media()

    def upload_media(self, filename, progress=None, data=None):
        """Upload a file to be hosted on the target BMC

        This will upload the specified data to
        the BMC so that it will make it available to the system as an emulated
        USB device.

        :param filename: The filename to use, the basename of the parameter
                         will be given to the bmc.
        :param progress: Optional callback for progress updates
        """
        self.oem_init()
        return self._oem.upload_media(filename, progress, data)

    def list_media(self):
        """List attached remote media

        :returns: An iterable list of attached media
        """
        self.oem_init()
        return self._oem.list_media()

    def get_licenses(self):
        self.oem_init()
        return self._oem.get_licenses()

    def delete_license(self, name):
        self.oem_init()
        return self._oem.delete_license(name)

    def save_licenses(self, directory):
        if os.path.exists(directory) and not os.path.isdir(directory):
            raise exc.InvalidParameterValue(
                'Not allowed to overwrite existing file: {0}'.format(
                    directory))
        self.oem_init()
        return self._oem.save_licenses(directory)

    def apply_license(self, filename, progress=None, data=None):
        self.oem_init()
        return self._oem.apply_license(filename, progress, data)

    def set_extended_privilleges(self, uid):
        """Set user extended privillege as 'KVM & VMedia Allowed'

        """
        self.oem_init()
        return self._oem.set_oem_extended_privilleges(uid)