summaryrefslogtreecommitdiff
path: root/NetworkPkg/DnsDxe/DnsProtocol.c
blob: 64fca6a55bf50cc56a2f4a61deb77c37170fa79b (plain)
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
/** @file
Implementation of EFI_DNS4_PROTOCOL and EFI_DNS6_PROTOCOL interfaces.

Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution.  The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#include "DnsImpl.h"

EFI_DNS4_PROTOCOL  mDns4Protocol = {
  Dns4GetModeData,
  Dns4Configure,
  Dns4HostNameToIp,
  Dns4IpToHostName,
  Dns4GeneralLookUp,
  Dns4UpdateDnsCache,
  Dns4Poll,
  Dns4Cancel
};

EFI_DNS6_PROTOCOL  mDns6Protocol = {
  Dns6GetModeData,
  Dns6Configure,
  Dns6HostNameToIp,
  Dns6IpToHostName,
  Dns6GeneralLookUp,
  Dns6UpdateDnsCache,
  Dns6Poll,
  Dns6Cancel
};

/**
  Retrieve mode data of this DNS instance.

  This function is used to retrieve DNS mode data for this DNS instance.

  @param[in]   This               Pointer to EFI_DNS4_PROTOCOL instance.
  @param[out]  DnsModeData        Point to the mode data.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_NOT_STARTED         When DnsConfigData is queried, no configuration data
                                  is available because this instance has not been
                                  configured.
  @retval EFI_INVALID_PARAMETER   This is NULL or DnsModeData is NULL.
  @retval EFI_OUT_OF_RESOURCES    Failed to allocate needed resources.
**/
EFI_STATUS
EFIAPI
Dns4GetModeData (
  IN  EFI_DNS4_PROTOCOL          *This,
  OUT EFI_DNS4_MODE_DATA         *DnsModeData
  )
{
  DNS_INSTANCE         *Instance;
  
  EFI_TPL              OldTpl;

  UINTN                Index;
  
  LIST_ENTRY           *Entry;
  LIST_ENTRY           *Next;
  
  DNS4_SERVER_IP       *ServerItem;
  EFI_IPv4_ADDRESS     *ServerList;
  DNS4_CACHE           *CacheItem;
  EFI_DNS4_CACHE_ENTRY *CacheList;
  EFI_STATUS           Status;

  ServerItem = NULL;
  ServerList = NULL;
  CacheItem  = NULL;
  CacheList  = NULL;
  Status     = EFI_SUCCESS;
  
    
  if ((This == NULL) || (DnsModeData == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
    
  Instance = DNS_INSTANCE_FROM_THIS_PROTOCOL4 (This);
  if (Instance->State == DNS_STATE_UNCONFIGED) {
    Status = EFI_NOT_STARTED;
    goto ON_EXIT;
  }
  
  ZeroMem (DnsModeData, sizeof (EFI_DNS4_MODE_DATA));

  //
  // Get the current configuration data of this instance. 
  //
  Status = Dns4CopyConfigure (&DnsModeData->DnsConfigData, &Instance->Dns4CfgData);
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  //
  // Get the DnsServerCount and DnsServerList
  //
  Index = 0;
  NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns4ServerList) {
    Index++;
  }
  DnsModeData->DnsServerCount = (UINT32) Index;
  ServerList = AllocatePool (sizeof (EFI_IPv4_ADDRESS) * DnsModeData->DnsServerCount);
  if (ServerList == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    Dns4CleanConfigure (&DnsModeData->DnsConfigData);
    goto ON_EXIT;
  }
  
  Index = 0;
  NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns4ServerList) {
    ServerItem = NET_LIST_USER_STRUCT (Entry, DNS4_SERVER_IP, AllServerLink);
    CopyMem (ServerList + Index, &ServerItem->Dns4ServerIp, sizeof (EFI_IPv4_ADDRESS));
    Index++;
  }
  DnsModeData->DnsServerList = ServerList;

  //
  // Get the DnsCacheCount and DnsCacheList
  //
  Index =0;
  NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns4CacheList) {
    Index++;
  }
  DnsModeData->DnsCacheCount = (UINT32) Index;
  CacheList = AllocatePool (sizeof (EFI_DNS4_CACHE_ENTRY) * DnsModeData->DnsCacheCount);
  if (CacheList == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    Dns4CleanConfigure (&DnsModeData->DnsConfigData);
    FreePool (ServerList);
    goto ON_EXIT;
  }
  
  Index =0;
  NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns4CacheList) {
    CacheItem = NET_LIST_USER_STRUCT (Entry, DNS4_CACHE, AllCacheLink);
    CopyMem (CacheList + Index, &CacheItem->DnsCache, sizeof (EFI_DNS4_CACHE_ENTRY));
    Index++;
  }
  DnsModeData->DnsCacheList = CacheList;

ON_EXIT:
  gBS->RestoreTPL (OldTpl);
  return Status;
}

/**
  Configure this DNS instance.

  This function is used to configure DNS mode data for this DNS instance.

  @param[in]  This                Pointer to EFI_DNS4_PROTOCOL instance.
  @param[in]  DnsConfigData       Point to the Configuration data.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_UNSUPPORTED         The designated protocol is not supported.
  @retval EFI_INVALID_PARAMTER    Thisis NULL.
                                  The StationIp address provided in DnsConfigData is not a 
                                  valid unicast.
                                  DnsServerList is NULL while DnsServerListCount
                                  is not ZERO.
                                  DnsServerListCount is ZERO while DnsServerList
                                  is not NULL
  @retval EFI_OUT_OF_RESOURCES    The DNS instance data or required space could not be
                                  allocated.
  @retval EFI_DEVICE_ERROR        An unexpected system or network error occurred. The
                                  EFI DNSv4 Protocol instance is not configured.
  @retval EFI_ALREADY_STARTED     Second call to Configure() with DnsConfigData. To 
                                  reconfigure the instance the caller must call Configure() 
                                  with NULL first to return driver to unconfigured state.
**/
EFI_STATUS
EFIAPI
Dns4Configure (
  IN EFI_DNS4_PROTOCOL           *This,
  IN EFI_DNS4_CONFIG_DATA        *DnsConfigData
  )
{
  EFI_STATUS                Status;
  DNS_INSTANCE              *Instance;
  
  EFI_TPL                   OldTpl;
  IP4_ADDR                  Ip;
  IP4_ADDR                  Netmask;

  UINT32                    ServerListCount;
  EFI_IPv4_ADDRESS          *ServerList;                  

  Status     = EFI_SUCCESS;
  ServerList = NULL;
    
  if (This == NULL || 
     (DnsConfigData != NULL && ((DnsConfigData->DnsServerListCount != 0 && DnsConfigData->DnsServerList == NULL) || 
                                (DnsConfigData->DnsServerListCount == 0 && DnsConfigData->DnsServerList != NULL)))) {
    return EFI_INVALID_PARAMETER;
  }

  if (DnsConfigData != NULL && DnsConfigData->Protocol != DNS_PROTOCOL_UDP) {
    return EFI_UNSUPPORTED;
  }

  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

  Instance = DNS_INSTANCE_FROM_THIS_PROTOCOL4 (This);

  if (DnsConfigData == NULL) {
    ZeroMem (&Instance->SessionDnsServer, sizeof (EFI_IP_ADDRESS));
    
    //
    // Reset the Instance if ConfigData is NULL
    //
    if (!NetMapIsEmpty(&Instance->Dns4TxTokens)) {
      Dns4InstanceCancelToken(Instance, NULL);
    }

    Instance->MaxRetry = 0;

    if (Instance->UdpIo != NULL){
      UdpIoCleanIo (Instance->UdpIo);
    }
    
    if (Instance->Dns4CfgData.DnsServerList != NULL) {
      FreePool (Instance->Dns4CfgData.DnsServerList);
    }
    ZeroMem (&Instance->Dns4CfgData, sizeof (EFI_DNS4_CONFIG_DATA));
    
    Instance->State = DNS_STATE_UNCONFIGED;
  } else {
    //
    // Configure the parameters for new operation.
    //
    CopyMem (&Ip, &DnsConfigData->StationIp, sizeof (IP4_ADDR));
    CopyMem (&Netmask, &DnsConfigData->SubnetMask, sizeof (IP4_ADDR));

    Ip       = NTOHL (Ip);
    Netmask  = NTOHL (Netmask);

    if (!DnsConfigData->UseDefaultSetting &&
       ((!IP4_IS_VALID_NETMASK (Netmask) || !NetIp4IsUnicast (Ip, Netmask)))) {
      Status = EFI_INVALID_PARAMETER;
      goto ON_EXIT;
    }

    Status = Dns4CopyConfigure (&Instance->Dns4CfgData, DnsConfigData);
    if (EFI_ERROR (Status)) {
      goto ON_EXIT;
    }

    if (DnsConfigData->DnsServerListCount == 0 || DnsConfigData->DnsServerList == NULL) {
      gBS->RestoreTPL (OldTpl); 
      
      //
      // The DNS instance will retrieve DNS server from DHCP Server
      //
      Status = GetDns4ServerFromDhcp4 (
                 Instance,
                 &ServerListCount, 
                 &ServerList
                 );
      if (EFI_ERROR (Status)) {
        return Status;
      }

      ASSERT(ServerList != NULL);
      
      OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

      CopyMem (&Instance->SessionDnsServer.v4, &ServerList[0], sizeof (EFI_IPv4_ADDRESS));
    } else {
      CopyMem (&Instance->SessionDnsServer.v4, &DnsConfigData->DnsServerList[0], sizeof (EFI_IPv4_ADDRESS));
    }

    //
    // Config UDP
    //
    Status = Dns4ConfigUdp (Instance, Instance->UdpIo);
    if (EFI_ERROR (Status)) {
      if (Instance->Dns4CfgData.DnsServerList != NULL) {
        FreePool (Instance->Dns4CfgData.DnsServerList);
      }
      goto ON_EXIT;
    }

    //
    // Add configured DNS server used by this instance to ServerList.
    //
    Status = AddDns4ServerIp (&mDriverData->Dns4ServerList, Instance->SessionDnsServer.v4);
    if (EFI_ERROR (Status)) {
      if (Instance->Dns4CfgData.DnsServerList != NULL) {
        FreePool (Instance->Dns4CfgData.DnsServerList);
      }
      goto ON_EXIT;
    }
    
    Instance->State = DNS_STATE_CONFIGED;
  }

ON_EXIT:
  gBS->RestoreTPL (OldTpl);
  return Status;
}

/**
  Host name to host address translation.

  The HostNameToIp () function is used to translate the host name to host IP address. A
  type A query is used to get the one or more IP addresses for this host.

  @param[in]  This                Pointer to EFI_DNS4_PROTOCOL instance.
  @param[in]  HostName            Host name.
  @param[in]  Token               Point to the completion token to translate host name
                                  to host address.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_INVALID_PARAMETER   One or more of the following conditions is TRUE:
                                  This is NULL.
                                  Token is NULL.
                                  Token.Event is NULL.
                                  HostName is NULL. HostName string is unsupported format.
  @retval EFI_NO_MAPPING          There's no source address is available for use.
  @retval EFI_NOT_STARTED         This instance has not been started.
**/
EFI_STATUS
EFIAPI
Dns4HostNameToIp (
  IN  EFI_DNS4_PROTOCOL          *This,
  IN  CHAR16                     *HostName,
  IN  EFI_DNS4_COMPLETION_TOKEN  *Token
  )
{
  EFI_STATUS            Status;
  
  DNS_INSTANCE          *Instance;
  
  EFI_DNS4_CONFIG_DATA  *ConfigData;
  
  UINTN                 Index;
  DNS4_CACHE            *Item;
  LIST_ENTRY            *Entry;
  LIST_ENTRY            *Next;
  
  CHAR8                 *QueryName;
  
  DNS4_TOKEN_ENTRY      *TokenEntry;
  NET_BUF               *Packet;
  
  EFI_TPL               OldTpl;
  
  Status     = EFI_SUCCESS;
  Item       = NULL;
  QueryName  = NULL;
  TokenEntry = NULL;
  Packet     = NULL;
  
  //
  // Validate the parameters
  //
  if ((This == NULL) || (HostName == NULL) || Token == NULL) {
    return EFI_INVALID_PARAMETER;
  }
  
  OldTpl   = gBS->RaiseTPL (TPL_CALLBACK);
  
  Instance = DNS_INSTANCE_FROM_THIS_PROTOCOL4 (This);
  
  ConfigData = &(Instance->Dns4CfgData);
  
  Instance->MaxRetry = ConfigData->RetryCount;
  
  Token->Status = EFI_NOT_READY;
  Token->RetryCount = 0;
  Token->RetryInterval = ConfigData->RetryInterval;

  if (Instance->State != DNS_STATE_CONFIGED) {
    Status = EFI_NOT_STARTED;
    goto ON_EXIT;
  }

  //
  // Check the MaxRetry and RetryInterval values.
  //
  if (Instance->MaxRetry == 0) {
    Instance->MaxRetry = DNS_DEFAULT_RETRY;
  }

  if (Token->RetryInterval < DNS_DEFAULT_TIMEOUT) {
    Token->RetryInterval = DNS_DEFAULT_TIMEOUT;
  }

  //
  // Check cache
  //
  if (ConfigData->EnableDnsCache) {
    Index = 0;
    NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns4CacheList) {
      Item = NET_LIST_USER_STRUCT (Entry, DNS4_CACHE, AllCacheLink);
      if (StrCmp (HostName, Item->DnsCache.HostName) == 0) {
        Index++;
      }
    }

    if (Index != 0) {
      Token->RspData.H2AData = AllocatePool (sizeof (DNS_HOST_TO_ADDR_DATA));
      if (Token->RspData.H2AData == NULL) {
        Status = EFI_OUT_OF_RESOURCES;
        goto ON_EXIT;
      }

      Token->RspData.H2AData->IpCount = (UINT32)Index;
      Token->RspData.H2AData->IpList = AllocatePool (sizeof (EFI_IPv4_ADDRESS) * Index);
      if (Token->RspData.H2AData->IpList == NULL) {
        if (Token->RspData.H2AData != NULL) {
          FreePool (Token->RspData.H2AData);
        }
        
        Status = EFI_OUT_OF_RESOURCES;
        goto ON_EXIT;
      }

      Index = 0;
      NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns4CacheList) {
        Item = NET_LIST_USER_STRUCT (Entry, DNS4_CACHE, AllCacheLink);
        if ((UINT32)Index < Token->RspData.H2AData->IpCount && StrCmp (HostName, Item->DnsCache.HostName) == 0) {
          CopyMem ((Token->RspData.H2AData->IpList) + Index, Item->DnsCache.IpAddress, sizeof (EFI_IPv4_ADDRESS));
          Index++; 
        }
      }
         
      Token->Status = EFI_SUCCESS;
          
      if (Token->Event != NULL) {
        gBS->SignalEvent (Token->Event);
        DispatchDpc ();
      }

      Status = Token->Status;
      goto ON_EXIT;
    } 
  }

  //
  // Construct DNS TokenEntry.
  //
  TokenEntry = AllocateZeroPool (sizeof(DNS4_TOKEN_ENTRY));
  if (TokenEntry == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }
  
  TokenEntry->PacketToLive = Token->RetryInterval;
  TokenEntry->QueryHostName = HostName;
  TokenEntry->Token = Token;

  //
  // Construct QName.
  //
  QueryName = NetLibCreateDnsQName (TokenEntry->QueryHostName);
  if (QueryName == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }
  
  //
  // Construct DNS Query Packet.
  //
  Status = ConstructDNSQuery (Instance, QueryName, DNS_TYPE_A, DNS_CLASS_INET, &Packet);
  if (EFI_ERROR (Status)) {
    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    goto ON_EXIT;
  }

  ASSERT (Packet != NULL);

  //
  // Save the token into the Dns4TxTokens map.
  //
  Status = NetMapInsertTail (&Instance->Dns4TxTokens, TokenEntry, Packet);
  if (EFI_ERROR (Status)) {
    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    NetbufFree (Packet);
    
    goto ON_EXIT;
  }
  
  //
  // Dns Query Ip
  //
  Status = DoDnsQuery (Instance, Packet);
  if (EFI_ERROR (Status)) {
    Dns4RemoveTokenEntry (&Instance->Dns4TxTokens, TokenEntry);

    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    NetbufFree (Packet);
  }
  
ON_EXIT:
  if (QueryName != NULL) {
    FreePool (QueryName);
  }
  
  gBS->RestoreTPL (OldTpl);
  return Status;
}

/**
  IPv4 address to host name translation also known as Reverse DNS lookup.

  The IpToHostName() function is used to translate the host address to host name. A type PTR 
  query is used to get the primary name of the host. Support of this function is optional.

  @param[in]  This                Pointer to EFI_DNS4_PROTOCOL instance.
  @param[in]  IpAddress           Ip Address.
  @param[in]  Token               Point to the completion token to translate host
                                  address to host name.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_UNSUPPORTED         This function is not supported.
  @retval EFI_INVALID_PARAMETER   One or more of the following conditions is TRUE:
                                  This is NULL.
                                  Token is NULL.
                                  Token.Event is NULL.
                                  IpAddress is not valid IP address .
  @retval EFI_NO_MAPPING          There's no source address is available for use.
  @retval EFI_ALREADY_STARTED     This Token is being used in another DNS session.
  @retval EFI_OUT_OF_RESOURCES    Failed to allocate needed resources.
**/
EFI_STATUS
EFIAPI
Dns4IpToHostName (
  IN  EFI_DNS4_PROTOCOL              *This,
  IN  EFI_IPv4_ADDRESS               IpAddress,
  IN  EFI_DNS4_COMPLETION_TOKEN      *Token
  )
{
  return EFI_UNSUPPORTED;
}

/**
  Retrieve arbitrary information from the DNS server. 

  This GeneralLookup() function retrieves arbitrary information from the DNS. The caller
  supplies a QNAME, QTYPE, and QCLASS, and all of the matching RRs are returned. All
  RR content (e.g., TTL) was returned. The caller need parse the returned RR to get
  required information. The function is optional.

  @param[in]  This                Pointer to EFI_DNS4_PROTOCOL instance.
  @param[in]  QName               Pointer to Query Name.
  @param[in]  QType               Query Type.
  @param[in]  QClass              Query Name.
  @param[in]  Token               Point to the completion token to retrieve arbitrary
                                  information.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_UNSUPPORTED         This function is not supported. Or the requested
                                  QType is not supported
  @retval EFI_INVALID_PARAMETER   One or more of the following conditions is TRUE:
                                  This is NULL.
                                  Token is NULL.
                                  Token.Event is NULL.
                                  QName is NULL.
  @retval EFI_NO_MAPPING          There's no source address is available for use.
  @retval EFI_ALREADY_STARTED     This Token is being used in another DNS session.
  @retval EFI_OUT_OF_RESOURCES    Failed to allocate needed resources.
**/
EFI_STATUS
EFIAPI
Dns4GeneralLookUp (
  IN  EFI_DNS4_PROTOCOL                *This,
  IN  CHAR8                            *QName,
  IN  UINT16                           QType, 
  IN  UINT16                           QClass,
  IN  EFI_DNS4_COMPLETION_TOKEN        *Token
  )
{
  EFI_STATUS            Status;
  
  DNS_INSTANCE          *Instance;
  
  EFI_DNS4_CONFIG_DATA  *ConfigData;
  
  DNS4_TOKEN_ENTRY      *TokenEntry;
  NET_BUF               *Packet;
  
  EFI_TPL               OldTpl;
  
  Status     = EFI_SUCCESS;
  TokenEntry = NULL;
  Packet     = NULL;
  
  //
  // Validate the parameters
  //
  if ((This == NULL) || (QName == NULL) || Token == NULL) {
    return EFI_INVALID_PARAMETER;
  }
  
  OldTpl   = gBS->RaiseTPL (TPL_CALLBACK);
  
  Instance = DNS_INSTANCE_FROM_THIS_PROTOCOL4 (This);
  
  ConfigData = &(Instance->Dns4CfgData);
  
  Instance->MaxRetry = ConfigData->RetryCount;
  
  Token->Status = EFI_NOT_READY;
  Token->RetryCount = 0;
  Token->RetryInterval = ConfigData->RetryInterval;

  if (Instance->State != DNS_STATE_CONFIGED) {
    Status = EFI_NOT_STARTED;
    goto ON_EXIT;
  }

  //
  // Check the MaxRetry and RetryInterval values.
  //
  if (Instance->MaxRetry == 0) {
    Instance->MaxRetry = DNS_DEFAULT_RETRY;
  }

  if (Token->RetryInterval < DNS_DEFAULT_TIMEOUT) {
    Token->RetryInterval = DNS_DEFAULT_TIMEOUT;
  }

  //
  // Construct DNS TokenEntry.
  //
  TokenEntry = AllocateZeroPool (sizeof(DNS4_TOKEN_ENTRY));
  if (TokenEntry == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }
  
  TokenEntry->PacketToLive = Token->RetryInterval;
  TokenEntry->GeneralLookUp = TRUE;
  TokenEntry->Token = Token;

  //
  // Construct DNS Query Packet.
  //
  Status = ConstructDNSQuery (Instance, QName, QType, QClass, &Packet);
  if (EFI_ERROR (Status)) {
    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    goto ON_EXIT;
  }

  ASSERT (Packet != NULL);

  //
  // Save the token into the Dns4TxTokens map.
  //
  Status = NetMapInsertTail (&Instance->Dns4TxTokens, TokenEntry, Packet);
  if (EFI_ERROR (Status)) {
    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    NetbufFree (Packet);
    
    goto ON_EXIT;
  }
  
  //
  // Dns Query Ip
  //
  Status = DoDnsQuery (Instance, Packet);
  if (EFI_ERROR (Status)) {
    Dns4RemoveTokenEntry (&Instance->Dns4TxTokens, TokenEntry);

    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    NetbufFree (Packet);
  }
  
ON_EXIT:
  gBS->RestoreTPL (OldTpl);
  return Status;
}

/**
  This function is to update the DNS Cache.

  The UpdateDnsCache() function is used to add/delete/modify DNS cache entry. DNS cache
  can be normally dynamically updated after the DNS resolve succeeds. This function
  provided capability to manually add/delete/modify the DNS cache.

  @param[in]  This                Pointer to EFI_DNS4_PROTOCOL instance.
  @param[in]  DeleteFlag          If FALSE, this function is to add one entry to the
                                  DNS Cahce. If TRUE, this function will delete
                                  matching DNS Cache entry.
  @param[in]  Override            If TRUE, the maching DNS cache entry will be
                                  overwritten with the supplied parameter. If FALSE,
                                  EFI_ACCESS_DENIED will be returned if the entry to
                                  be added is already existed.
  @param[in]  DnsCacheEntry       Pointer to DNS Cache entry.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_INVALID_PARAMETER   One or more of the following conditions is TRUE:
                                  This is NULL.
                                  DnsCacheEntry.HostName is NULL.
                                  DnsCacheEntry.IpAddress is NULL.
                                  DnsCacheEntry.Timeout is zero.
  @retval EFI_ACCESS_DENIED       The DNS cache entry already exists and Override is
                                  not TRUE.
**/
EFI_STATUS
EFIAPI
Dns4UpdateDnsCache (
  IN EFI_DNS4_PROTOCOL      *This,
  IN BOOLEAN                DeleteFlag,
  IN BOOLEAN                Override,
  IN EFI_DNS4_CACHE_ENTRY   DnsCacheEntry
  )
{
  EFI_STATUS    Status; 
  EFI_TPL       OldTpl;

  Status = EFI_SUCCESS;
  
  if (DnsCacheEntry.HostName == NULL || DnsCacheEntry.IpAddress == NULL || DnsCacheEntry.Timeout == 0) {
    return EFI_INVALID_PARAMETER; 
  }
  
  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

  //
  // Update Dns4Cache here.
  //
  Status = UpdateDns4Cache (&mDriverData->Dns4CacheList, DeleteFlag, Override, DnsCacheEntry);

  gBS->RestoreTPL (OldTpl);
  
  return Status;
}

/**
  Polls for incoming data packets and processes outgoing data packets.

  The Poll() function can be used by network drivers and applications to increase the
  rate that data packets are moved between the communications device and the transmit
  and receive queues.
  In some systems, the periodic timer event in the managed network driver may not poll
  the underlying communications device fast enough to transmit and/or receive all data
  packets without missing incoming packets or dropping outgoing packets. Drivers and
  applications that are experiencing packet loss should try calling the Poll()
  function more often.

  @param[in]  This                Pointer to EFI_DNS4_PROTOCOL instance.

  @retval EFI_SUCCESS             Incoming or outgoing data was processed.
  @retval EFI_NOT_STARTED         This EFI DNS Protocol instance has not been started.
  @retval EFI_INVALID_PARAMETER   This is NULL.
  @retval EFI_DEVICE_ERROR        An unexpected system or network error occurred.
  @retval EFI_TIMEOUT             Data was dropped out of the transmit and/or receive
                                  queue. Consider increasing the polling rate.
**/
EFI_STATUS
EFIAPI
Dns4Poll (
  IN EFI_DNS4_PROTOCOL    *This
  )
{
  DNS_INSTANCE           *Instance;
  EFI_UDP4_PROTOCOL      *Udp;

  if (This == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = DNS_INSTANCE_FROM_THIS_PROTOCOL4 (This);

  if (Instance->State == DNS_STATE_UNCONFIGED) {
    return EFI_NOT_STARTED;
  } else if (Instance->State == DNS_STATE_DESTROY) {
    return EFI_DEVICE_ERROR;
  }

  Udp = Instance->UdpIo->Protocol.Udp4;
  
  return Udp->Poll (Udp);
}

/**
  Abort an asynchronous DNS operation, including translation between IP and Host, and
  general look up behavior.

  The Cancel() function is used to abort a pending resolution request. After calling
  this function, Token.Status will be set to EFI_ABORTED and then Token.Event will be
  signaled. If the token is not in one of the queues, which usually means that the
  asynchronous operation has completed, this function will not signal the token and
  EFI_NOT_FOUND is returned.

  @param[in]  This                Pointer to EFI_DNS4_PROTOCOL instance.
  @param[in]  Token               Pointer to a token that has been issued by
                                  EFI_DNS4_PROTOCOL.HostNameToIp (),
                                  EFI_DNS4_PROTOCOL.IpToHostName() or
                                  EFI_DNS4_PROTOCOL.GeneralLookup().
                                  If NULL, all pending tokens are aborted.

  @retval EFI_SUCCESS             Incoming or outgoing data was processed.
  @retval EFI_NOT_STARTED         This EFI DNS4 Protocol instance has not been started.
  @retval EFI_INVALID_PARAMETER   This is NULL.
  @retval EFI_NOT_FOUND           When Token is not NULL, and the asynchronous DNS
                                  operation was not found in the transmit queue. It
                                  was either completed or was not issued by
                                  HostNameToIp(), IpToHostName() or GeneralLookup().
**/
EFI_STATUS
EFIAPI
Dns4Cancel (
  IN  EFI_DNS4_PROTOCOL          *This,
  IN  EFI_DNS4_COMPLETION_TOKEN  *Token
  )
{
  EFI_STATUS          Status;
  DNS_INSTANCE        *Instance;
  EFI_TPL             OldTpl;

  if (This == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = DNS_INSTANCE_FROM_THIS_PROTOCOL4 (This);

  if (Instance->State == DNS_STATE_UNCONFIGED) {
    return EFI_NOT_STARTED;
  }

  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

  //
  // Cancle the tokens specified by Token for this instance.
  //
  Status = Dns4InstanceCancelToken (Instance, Token);

  //
  // Dispatch the DPC queued by the NotifyFunction of the canceled token's events.
  //
  DispatchDpc ();

  gBS->RestoreTPL (OldTpl);

  return Status;
}

/**
  Retrieve mode data of this DNS instance.

  This function is used to retrieve DNS mode data for this DNS instance.

  @param[in]   This                Pointer to EFI_DNS6_PROTOCOL instance.
  @param[out]  DnsModeData         Pointer to the caller-allocated storage for the 
                                   EFI_DNS6_MODE_DATA data.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_NOT_STARTED         When DnsConfigData is queried, no configuration data
                                  is available because this instance has not been
                                  configured.
  @retval EFI_INVALID_PARAMETER   This is NULL or DnsModeData is NULL.
  @retval EFI_OUT_OF_RESOURCE     Failed to allocate needed resources.
**/
EFI_STATUS
EFIAPI
Dns6GetModeData (
  IN  EFI_DNS6_PROTOCOL          *This,
  OUT EFI_DNS6_MODE_DATA         *DnsModeData
  )
{
  DNS_INSTANCE         *Instance;
  
  EFI_TPL              OldTpl;

  UINTN                Index;
  
  LIST_ENTRY           *Entry;
  LIST_ENTRY           *Next;

  DNS6_SERVER_IP       *ServerItem;
  EFI_IPv6_ADDRESS     *ServerList;
  DNS6_CACHE           *CacheItem;
  EFI_DNS6_CACHE_ENTRY *CacheList;
  EFI_STATUS           Status;

  ServerItem = NULL;
  ServerList = NULL;
  CacheItem  = NULL;
  CacheList  = NULL;
  Status     = EFI_SUCCESS;

  if ((This == NULL) || (DnsModeData == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
    
  Instance  = DNS_INSTANCE_FROM_THIS_PROTOCOL6 (This);
  if (Instance->State == DNS_STATE_UNCONFIGED) {
    Status =  EFI_NOT_STARTED;
    goto ON_EXIT;
  }

  ZeroMem (DnsModeData, sizeof (EFI_DNS6_MODE_DATA));

  //
  // Get the current configuration data of this instance. 
  //
  Status = Dns6CopyConfigure (&DnsModeData->DnsConfigData, &Instance->Dns6CfgData);
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }
  
  //
  // Get the DnsServerCount and DnsServerList
  //
  Index = 0;
  NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns6ServerList) {
    Index++;
  }
  DnsModeData->DnsServerCount = (UINT32) Index;
  ServerList = AllocatePool (sizeof(EFI_IPv6_ADDRESS) * DnsModeData->DnsServerCount);
  if (ServerList == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    Dns6CleanConfigure (&DnsModeData->DnsConfigData);
    goto ON_EXIT;
  }
  
  Index = 0;
  NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns6ServerList) {
    ServerItem = NET_LIST_USER_STRUCT (Entry, DNS6_SERVER_IP, AllServerLink);
    CopyMem (ServerList + Index, &ServerItem->Dns6ServerIp, sizeof (EFI_IPv6_ADDRESS));
    Index++;
  }
  DnsModeData->DnsServerList = ServerList;

  //
  // Get the DnsCacheCount and DnsCacheList
  //
  Index =0;
  NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns6CacheList) {
    Index++;
  }
  DnsModeData->DnsCacheCount = (UINT32) Index;
  CacheList = AllocatePool (sizeof(EFI_DNS6_CACHE_ENTRY) * DnsModeData->DnsCacheCount);
  if (CacheList == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    Dns6CleanConfigure (&DnsModeData->DnsConfigData);
    FreePool (ServerList);
    goto ON_EXIT;
  }
  
  Index =0;
  NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns6CacheList) {
    CacheItem = NET_LIST_USER_STRUCT (Entry, DNS6_CACHE, AllCacheLink);
    CopyMem (CacheList + Index, &CacheItem->DnsCache, sizeof (EFI_DNS6_CACHE_ENTRY));
    Index++;
  }
  DnsModeData->DnsCacheList = CacheList;
  
ON_EXIT:
  gBS->RestoreTPL (OldTpl);
  return Status;
}

/**
  Configure this DNS instance.

  The Configure() function is used to set and change the configuration data for this
  EFI DNSv6 Protocol driver instance. Reset the DNS instance if DnsConfigData is NULL.

  @param[in]  This                Pointer to EFI_DNS6_PROTOCOL instance.
  @param[in]  DnsConfigData       Pointer to the configuration data structure. All associated 
                                  storage to be allocated and released by caller.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_INVALID_PARAMTER    This is NULL.
                                  The StationIp address provided in DnsConfigData is not zero and not a valid unicast.
                                  DnsServerList is NULL while DnsServerList Count is not ZERO.
                                  DnsServerList Count is ZERO while DnsServerList is not NULL.
  @retval EFI_OUT_OF_RESOURCES    The DNS instance data or required space could not be allocated.
  @retval EFI_DEVICE_ERROR        An unexpected system or network error occurred. The
                                  EFI DNSv6 Protocol instance is not configured.
  @retval EFI_UNSUPPORTED         The designated protocol is not supported.
  @retval EFI_ALREADY_STARTED     Second call to Configure() with DnsConfigData. To 
                                  reconfigure the instance the caller must call Configure() with 
                                  NULL first to return driver to unconfigured state.
**/
EFI_STATUS
EFIAPI
Dns6Configure (
  IN EFI_DNS6_PROTOCOL           *This,
  IN EFI_DNS6_CONFIG_DATA        *DnsConfigData
  )
{
  EFI_STATUS                Status;
  DNS_INSTANCE              *Instance;
  
  EFI_TPL                   OldTpl;

  UINT32                    ServerListCount;
  EFI_IPv6_ADDRESS          *ServerList; 

  Status     = EFI_SUCCESS;
  ServerList = NULL;

  if (This == NULL || 
     (DnsConfigData != NULL && ((DnsConfigData->DnsServerCount != 0 && DnsConfigData->DnsServerList == NULL) || 
                                (DnsConfigData->DnsServerCount == 0 && DnsConfigData->DnsServerList != NULL)))) {
    return EFI_INVALID_PARAMETER;
  }

  if (DnsConfigData != NULL && DnsConfigData->Protocol != DNS_PROTOCOL_UDP) {
    return EFI_UNSUPPORTED;
  }

  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

  Instance = DNS_INSTANCE_FROM_THIS_PROTOCOL6 (This);

  if (DnsConfigData == NULL) {
    ZeroMem (&Instance->SessionDnsServer, sizeof (EFI_IP_ADDRESS));

    //
    // Reset the Instance if ConfigData is NULL
    //
    if (!NetMapIsEmpty(&Instance->Dns6TxTokens)) {
      Dns6InstanceCancelToken(Instance, NULL);
    }

    Instance->MaxRetry = 0;

    if (Instance->UdpIo != NULL){
      UdpIoCleanIo (Instance->UdpIo);
    }

    if (Instance->Dns6CfgData.DnsServerList != NULL) {
      FreePool (Instance->Dns6CfgData.DnsServerList);
    }
    ZeroMem (&Instance->Dns6CfgData, sizeof (EFI_DNS6_CONFIG_DATA));
    
    Instance->State = DNS_STATE_UNCONFIGED;
  } else {
    //
    // Configure the parameters for new operation.
    //
    if (!NetIp6IsUnspecifiedAddr (&DnsConfigData->StationIp) && !NetIp6IsValidUnicast (&DnsConfigData->StationIp)) {
      Status = EFI_INVALID_PARAMETER;
      goto ON_EXIT;
    }

    Status = Dns6CopyConfigure (&Instance->Dns6CfgData, DnsConfigData);
    if (EFI_ERROR (Status)) {
      goto ON_EXIT;
    }

    if (DnsConfigData->DnsServerCount == 0 || DnsConfigData->DnsServerList == NULL) {
      gBS->RestoreTPL (OldTpl);

      //
      //The DNS instance will retrieve DNS server from DHCP Server.
      //
      Status = GetDns6ServerFromDhcp6 (
                 Instance->Service->ImageHandle,
                 Instance->Service->ControllerHandle, 
                 &ServerListCount, 
                 &ServerList
                 );
      if (EFI_ERROR (Status)) {
        goto ON_EXIT;
      }
      
      ASSERT(ServerList != NULL);

      OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

      CopyMem (&Instance->SessionDnsServer.v6, &ServerList[0], sizeof (EFI_IPv6_ADDRESS));
    } else {
      CopyMem (&Instance->SessionDnsServer.v6, &DnsConfigData->DnsServerList[0], sizeof (EFI_IPv6_ADDRESS));
    }

    //
    // Config UDP
    //
    Status = Dns6ConfigUdp (Instance, Instance->UdpIo);
    if (EFI_ERROR (Status)) {
      if (Instance->Dns6CfgData.DnsServerList != NULL) {
        FreePool (Instance->Dns6CfgData.DnsServerList);
      }
      goto ON_EXIT;
    }

    //
    // Add configured DNS server used by this instance to ServerList.
    //
    Status = AddDns6ServerIp (&mDriverData->Dns6ServerList, Instance->SessionDnsServer.v6);
    if (EFI_ERROR (Status)) {
      if (Instance->Dns6CfgData.DnsServerList != NULL) {
        FreePool (Instance->Dns6CfgData.DnsServerList);
      }
      goto ON_EXIT;
    }
    
    Instance->State = DNS_STATE_CONFIGED;
  }

ON_EXIT:
  gBS->RestoreTPL (OldTpl);
  return Status;
}

/**
  Host name to host address translation.

  The HostNameToIp () function is used to translate the host name to host IP address. A
  type AAAA query is used to get the one or more IPv6 addresses for this host.

  @param[in]  This                Pointer to EFI_DNS6_PROTOCOL instance.
  @param[in]  HostName            Host name.
  @param[in]  Token               Point to the completion token to translate host name
                                  to host address.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_INVALID_PARAMETER   One or more of the following conditions is TRUE:
                                  This is NULL.
                                  Token is NULL.
                                  Token.Event is NULL.
                                  HostName is NULL or buffer contained unsupported characters.
  @retval EFI_NO_MAPPING          There's no source address is available for use.
  @retval EFI_ALREADY_STARTED     This Token is being used in another DNS session.
  @retval EFI_NOT_STARTED         This instance has not been started.
  @retval EFI_OUT_OF_RESOURCES    Failed to allocate needed resources.
**/
EFI_STATUS
EFIAPI
Dns6HostNameToIp (
  IN  EFI_DNS6_PROTOCOL          *This,
  IN  CHAR16                     *HostName,
  IN  EFI_DNS6_COMPLETION_TOKEN  *Token
  )
{
  EFI_STATUS            Status;
  
  DNS_INSTANCE          *Instance;

  EFI_DNS6_CONFIG_DATA  *ConfigData;
  
  UINTN                 Index; 
  DNS6_CACHE            *Item;
  LIST_ENTRY            *Entry;
  LIST_ENTRY            *Next;
  
  CHAR8                 *QueryName;
  
  DNS6_TOKEN_ENTRY      *TokenEntry;
  NET_BUF               *Packet;
  
  EFI_TPL               OldTpl;
  
  Status     = EFI_SUCCESS;
  Item       = NULL;
  QueryName  = NULL;
  TokenEntry = NULL;
  Packet     = NULL;

  //
  // Validate the parameters
  //
  if ((This == NULL) || (HostName == NULL) || Token == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  OldTpl   = gBS->RaiseTPL (TPL_CALLBACK);
  
  Instance = DNS_INSTANCE_FROM_THIS_PROTOCOL6 (This);
  
  ConfigData = &(Instance->Dns6CfgData);
  
  Instance->MaxRetry = ConfigData->RetryCount;

  Token->Status = EFI_NOT_READY;
  Token->RetryCount = 0;
  Token->RetryInterval = ConfigData->RetryInterval;

  if (Instance->State != DNS_STATE_CONFIGED) {
    Status = EFI_NOT_STARTED;
    goto ON_EXIT;
  }

  //
  // Check the MaxRetry and RetryInterval values.
  //
  if (Instance->MaxRetry == 0) {
    Instance->MaxRetry = DNS_DEFAULT_RETRY;
  }

  if (Token->RetryInterval < DNS_DEFAULT_TIMEOUT) {
    Token->RetryInterval = DNS_DEFAULT_TIMEOUT;
  } 

  //
  // Check cache
  //
  if (ConfigData->EnableDnsCache) {
    Index = 0;
    NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns6CacheList) {
      Item = NET_LIST_USER_STRUCT (Entry, DNS6_CACHE, AllCacheLink);
      if (StrCmp (HostName, Item->DnsCache.HostName) == 0) {
        Index++;
      }
    }

    if (Index != 0) {
      Token->RspData.H2AData = AllocatePool (sizeof (DNS6_HOST_TO_ADDR_DATA));
      if (Token->RspData.H2AData == NULL) {
        Status = EFI_OUT_OF_RESOURCES;
        goto ON_EXIT;
      }

      Token->RspData.H2AData->IpCount = (UINT32)Index;
      Token->RspData.H2AData->IpList = AllocatePool (sizeof (EFI_IPv6_ADDRESS) * Index);
      if (Token->RspData.H2AData->IpList == NULL) {
        if (Token->RspData.H2AData != NULL) {
          FreePool (Token->RspData.H2AData);
        }
        
        Status = EFI_OUT_OF_RESOURCES;
        goto ON_EXIT;
      }

      Index = 0;
      NET_LIST_FOR_EACH_SAFE (Entry, Next, &mDriverData->Dns6CacheList) {
        Item = NET_LIST_USER_STRUCT (Entry, DNS6_CACHE, AllCacheLink);
        if ((UINT32)Index < Token->RspData.H2AData->IpCount && StrCmp (HostName, Item->DnsCache.HostName) == 0) {
          CopyMem ((Token->RspData.H2AData->IpList) + Index, Item->DnsCache.IpAddress, sizeof (EFI_IPv6_ADDRESS));
          Index++;
        }
      }
         
      Token->Status = EFI_SUCCESS;
          
      if (Token->Event != NULL) {
        gBS->SignalEvent (Token->Event);
        DispatchDpc ();
      }
      
      Status = Token->Status;
      goto ON_EXIT;
    } 
  }

  //
  // Construct DNS TokenEntry.
  //
  TokenEntry = AllocateZeroPool (sizeof (DNS6_TOKEN_ENTRY));
  if (TokenEntry == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }
  
  TokenEntry->PacketToLive = Token->RetryInterval;
  TokenEntry->QueryHostName = HostName;
  TokenEntry->Token = Token;


  //
  // Construct QName.
  //
  QueryName = NetLibCreateDnsQName (TokenEntry->QueryHostName);
  if (QueryName == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }
  
  //
  // Construct DNS Query Packet.
  //
  Status = ConstructDNSQuery (Instance, QueryName, DNS_TYPE_AAAA, DNS_CLASS_INET, &Packet);
  if (EFI_ERROR (Status)) {
    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    goto ON_EXIT;
  }

  ASSERT (Packet != NULL);

  //
  // Save the token into the Dns6TxTokens map.
  //
  Status = NetMapInsertTail (&Instance->Dns6TxTokens, TokenEntry, Packet);
  if (EFI_ERROR (Status)) {
    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    NetbufFree (Packet);
    
    goto ON_EXIT;
  }
  
  //
  // Dns Query Ip
  //
  Status = DoDnsQuery (Instance, Packet);
  if (EFI_ERROR (Status)) {
    Dns6RemoveTokenEntry (&Instance->Dns6TxTokens, TokenEntry);
    
    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    NetbufFree (Packet);
  }
  
ON_EXIT:
  if (QueryName != NULL) {
    FreePool (QueryName);
  }
  
  gBS->RestoreTPL (OldTpl);
  return Status;
}

/**
  Host address to host name translation.

  The IpToHostName () function is used to translate the host address to host name. A
  type PTR query is used to get the primary name of the host. Implementation can choose
  to support this function or not.

  @param[in]  This                Pointer to EFI_DNS6_PROTOCOL instance.
  @param[in]  IpAddress           Ip Address.
  @param[in]  Token               Point to the completion token to translate host
                                  address to host name.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_UNSUPPORTED         This function is not supported.
  @retval EFI_INVALID_PARAMETER   One or more of the following conditions is TRUE:
                                  This is NULL.
                                  Token is NULL.
                                  Token.Event is NULL.
                                  IpAddress is not valid IP address.
  @retval EFI_NO_MAPPING          There's no source address is available for use.
  @retval EFI_NOT_STARTED         This instance has not been started.
  @retval EFI_OUT_OF_RESOURCES    Failed to allocate needed resources.
**/
EFI_STATUS
EFIAPI
Dns6IpToHostName (
  IN  EFI_DNS6_PROTOCOL              *This,
  IN  EFI_IPv6_ADDRESS               IpAddress,
  IN  EFI_DNS6_COMPLETION_TOKEN      *Token
  )
{
  return EFI_UNSUPPORTED;
}

/**
  This function provides capability to retrieve arbitrary information from the DNS
  server.

  This GeneralLookup() function retrieves arbitrary information from the DNS. The caller
  supplies a QNAME, QTYPE, and QCLASS, and all of the matching RRs are returned. All
  RR content (e.g., TTL) was returned. The caller need parse the returned RR to get
  required information. The function is optional. Implementation can choose to support
  it or not.

  @param[in]  This                Pointer to EFI_DNS6_PROTOCOL instance.
  @param[in]  QName               Pointer to Query Name.
  @param[in]  QType               Query Type.
  @param[in]  QClass              Query Name.
  @param[in]  Token               Point to the completion token to retrieve arbitrary
                                  information.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_UNSUPPORTED         This function is not supported. Or the requested
                                  QType is not supported
  @retval EFI_INVALID_PARAMETER   One or more of the following conditions is TRUE:
                                  This is NULL.
                                  Token is NULL.
                                  Token.Event is NULL.
                                  QName is NULL.
  @retval EFI_NO_MAPPING          There's no source address is available for use.
  @retval EFI_NOT_STARTED         This instance has not been started.
  @retval EFI_OUT_OF_RESOURCES    Failed to allocate needed resources.
**/
EFI_STATUS
EFIAPI
Dns6GeneralLookUp (
  IN  EFI_DNS6_PROTOCOL                 *This,
  IN  CHAR8                             *QName,
  IN  UINT16                            QType, 
  IN  UINT16                            QClass,
  IN  EFI_DNS6_COMPLETION_TOKEN         *Token
  )
{
  EFI_STATUS            Status;
  
  DNS_INSTANCE          *Instance;
  
  EFI_DNS6_CONFIG_DATA  *ConfigData;
  
  DNS6_TOKEN_ENTRY      *TokenEntry;
  NET_BUF               *Packet;
  
  EFI_TPL               OldTpl;
  
  Status     = EFI_SUCCESS;
  TokenEntry = NULL;
  Packet     = NULL;
  
  //
  // Validate the parameters
  //
  if ((This == NULL) || (QName == NULL) || Token == NULL) {
    return EFI_INVALID_PARAMETER;
  }
  
  OldTpl   = gBS->RaiseTPL (TPL_CALLBACK);
  
  Instance = DNS_INSTANCE_FROM_THIS_PROTOCOL6 (This);
  
  ConfigData = &(Instance->Dns6CfgData);
  
  Instance->MaxRetry = ConfigData->RetryCount;
  
  Token->Status = EFI_NOT_READY;
  Token->RetryCount = 0;
  Token->RetryInterval = ConfigData->RetryInterval;

  if (Instance->State != DNS_STATE_CONFIGED) {
    Status = EFI_NOT_STARTED;
    goto ON_EXIT;
  }

  //
  // Check the MaxRetry and RetryInterval values.
  //
  if (Instance->MaxRetry == 0) {
    Instance->MaxRetry = DNS_DEFAULT_RETRY;
  }

  if (Token->RetryInterval < DNS_DEFAULT_TIMEOUT) {
    Token->RetryInterval = DNS_DEFAULT_TIMEOUT;
  }

  //
  // Construct DNS TokenEntry.
  //
  TokenEntry = AllocateZeroPool (sizeof(DNS6_TOKEN_ENTRY));
  if (TokenEntry == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }
  
  TokenEntry->PacketToLive = Token->RetryInterval;
  TokenEntry->GeneralLookUp = TRUE;
  TokenEntry->Token = Token;

  //
  // Construct DNS Query Packet.
  //
  Status = ConstructDNSQuery (Instance, QName, QType, QClass, &Packet);
  if (EFI_ERROR (Status)) {
    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    goto ON_EXIT;
  }

  ASSERT (Packet != NULL);

  //
  // Save the token into the Dns6TxTokens map.
  //
  Status = NetMapInsertTail (&Instance->Dns6TxTokens, TokenEntry, Packet);
  if (EFI_ERROR (Status)) {
    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    NetbufFree (Packet);
    
    goto ON_EXIT;
  }
  
  //
  // Dns Query Ip
  //
  Status = DoDnsQuery (Instance, Packet);
  if (EFI_ERROR (Status)) {
    Dns6RemoveTokenEntry (&Instance->Dns6TxTokens, TokenEntry);

    if (TokenEntry != NULL) {
      FreePool (TokenEntry);
    }
    
    NetbufFree (Packet);
  }
  
ON_EXIT:
  gBS->RestoreTPL (OldTpl);
  return Status;
}

/**
  This function is to update the DNS Cache.

  The UpdateDnsCache() function is used to add/delete/modify DNS cache entry. DNS cache
  can be normally dynamically updated after the DNS resolve succeeds. This function
  provided capability to manually add/delete/modify the DNS cache.

  @param[in]  This                Pointer to EFI_DNS6_PROTOCOL instance.
  @param[in]  DeleteFlag          If FALSE, this function is to add one entry to the
                                  DNS Cahce. If TRUE, this function will delete
                                  matching DNS Cache entry.
  @param[in]  Override            If TRUE, the maching DNS cache entry will be
                                  overwritten with the supplied parameter. If FALSE,
                                  EFI_ACCESS_DENIED will be returned if the entry to
                                  be added is already existed.
  @param[in]  DnsCacheEntry       Pointer to DNS Cache entry.

  @retval EFI_SUCCESS             The operation completed successfully.
  @retval EFI_INVALID_PARAMETER   One or more of the following conditions is TRUE:
                                  This is NULL.
                                  DnsCacheEntry.HostName is NULL.
                                  DnsCacheEntry.IpAddress is NULL.
                                  DnsCacheEntry.Timeout is zero.
  @retval EFI_ACCESS_DENIED       The DNS cache entry already exists and Override is
                                  not TRUE.
  @retval EFI_OUT_OF_RESOURCE     Failed to allocate needed resources.
**/
EFI_STATUS
EFIAPI
Dns6UpdateDnsCache (
  IN EFI_DNS6_PROTOCOL      *This,
  IN BOOLEAN                DeleteFlag,
  IN BOOLEAN                Override,
  IN EFI_DNS6_CACHE_ENTRY   DnsCacheEntry
  )
{
  EFI_STATUS    Status; 
  EFI_TPL       OldTpl;

  Status = EFI_SUCCESS;
  
  if (DnsCacheEntry.HostName == NULL || DnsCacheEntry.IpAddress == NULL || DnsCacheEntry.Timeout == 0) {
    return EFI_INVALID_PARAMETER; 
  }
  
  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

  //
  // Update Dns6Cache here.
  //
  Status = UpdateDns6Cache (&mDriverData->Dns6CacheList, DeleteFlag, Override, DnsCacheEntry);
  
  gBS->RestoreTPL (OldTpl);
  
  return Status;
}

/**
  Polls for incoming data packets and processes outgoing data packets.

  The Poll() function can be used by network drivers and applications to increase the
  rate that data packets are moved between the communications device and the transmit
  and receive queues.

  In some systems, the periodic timer event in the managed network driver may not poll
  the underlying communications device fast enough to transmit and/or receive all data
  packets without missing incoming packets or dropping outgoing packets. Drivers and
  applications that are experiencing packet loss should try calling the Poll()
  function more often.

  @param[in]  This                Pointer to EFI_DNS6_PROTOCOL instance.

  @retval EFI_SUCCESS             Incoming or outgoing data was processed.
  @retval EFI_NOT_STARTED         This EFI DNS Protocol instance has not been started.
  @retval EFI_INVALID_PARAMETER   This is NULL.
  @retval EFI_NO_MAPPING          There is no source address is available for use.
  @retval EFI_DEVICE_ERROR        An unexpected system or network error occurred.
  @retval EFI_TIMEOUT             Data was dropped out of the transmit and/or receive
                                  queue. Consider increasing the polling rate.
**/
EFI_STATUS
EFIAPI
Dns6Poll (
  IN EFI_DNS6_PROTOCOL    *This
  )
{
  DNS_INSTANCE           *Instance;
  EFI_UDP6_PROTOCOL      *Udp;

  if (This == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = DNS_INSTANCE_FROM_THIS_PROTOCOL6 (This);

  if (Instance->State == DNS_STATE_UNCONFIGED) {
    return EFI_NOT_STARTED;
  } else if (Instance->State == DNS_STATE_DESTROY) {
    return EFI_DEVICE_ERROR;
  }

  Udp = Instance->UdpIo->Protocol.Udp6;
  
  return Udp->Poll (Udp);
}

/**
  Abort an asynchronous DNS operation, including translation between IP and Host, and
  general look up behavior.

  The Cancel() function is used to abort a pending resolution request. After calling
  this function, Token.Status will be set to EFI_ABORTED and then Token.Event will be
  signaled. If the token is not in one of the queues, which usually means that the
  asynchronous operation has completed, this function will not signal the token and
  EFI_NOT_FOUND is returned.

  @param[in]  This                Pointer to EFI_DNS6_PROTOCOL instance.
  @param[in]  Token               Pointer to a token that has been issued by
                                  EFI_DNS6_PROTOCOL.HostNameToIp (),
                                  EFI_DNS6_PROTOCOL.IpToHostName() or
                                  EFI_DNS6_PROTOCOL.GeneralLookup().
                                  If NULL, all pending tokens are aborted.

  @retval EFI_SUCCESS             Incoming or outgoing data was processed.
  @retval EFI_NOT_STARTED         This EFI DNS6 Protocol instance has not been started.
  @retval EFI_INVALID_PARAMETER   This is NULL.
  @retval EFI_NO_MAPPING          There's no source address is available for use.
  @retval EFI_NOT_FOUND           When Token is not NULL, and the asynchronous DNS
                                  operation was not found in the transmit queue. It
                                  was either completed or was not issued by
                                  HostNameToIp(), IpToHostName() or GeneralLookup().
**/
EFI_STATUS
EFIAPI
Dns6Cancel (
  IN  EFI_DNS6_PROTOCOL          *This,
  IN  EFI_DNS6_COMPLETION_TOKEN  *Token
  )
{
  EFI_STATUS          Status;
  DNS_INSTANCE        *Instance;
  EFI_TPL             OldTpl;

  if (This == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = DNS_INSTANCE_FROM_THIS_PROTOCOL6 (This);

  if (Instance->State == DNS_STATE_UNCONFIGED) {
    return EFI_NOT_STARTED;
  }

  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

  //
  // Cancle the tokens specified by Token for this instance.
  //
  Status = Dns6InstanceCancelToken (Instance, Token);

  //
  // Dispatch the DPC queued by the NotifyFunction of the canceled token's events.
  //
  DispatchDpc ();

  gBS->RestoreTPL (OldTpl);

  return Status;
}