summaryrefslogtreecommitdiff
path: root/NetworkPkg/Dhcp6Dxe/Dhcp6Utility.c
blob: be7a9855519743e5bc4f3c34091b7f1ed81bc026 (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
/** @file
  Dhcp6 support functions implementation.

  Copyright (c) 2009 - 2010, 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 "Dhcp6Impl.h"


/**
  Generate client Duid in the format of Duid-llt.

  @param[in]  Mode          The pointer to the mode of SNP.

  @retval     NULL          If it failed to generate a client Id.
  @retval     others        The pointer to the new client id.

**/
EFI_DHCP6_DUID *
Dhcp6GenerateClientId (
  IN EFI_SIMPLE_NETWORK_MODE   *Mode
  )
{
  EFI_STATUS                Status;
  EFI_DHCP6_DUID            *Duid;
  EFI_TIME                  Time;
  UINT32                    Stamp;

  //
  // Attempt to get client Id from variable to keep it constant.
  // See details in section-9 of rfc-3315.
  //
  Duid = GetVariable (L"ClientId", &gEfiDhcp6ServiceBindingProtocolGuid);
  if (Duid != NULL) {
    return Duid;
  }

  //
  // Generate a time stamp of the seconds from 2000/1/1, assume 30day/month.
  //
  gRT->GetTime (&Time, NULL);
  Stamp = (UINT32)
    (
      (((((Time.Year - 2000) * 360 + (Time.Month - 1)) * 30 + (Time.Day - 1)) * 24 + Time.Hour) * 60 + Time.Minute) *
      60 +
      Time.Second
    );

  //
  //  The format of client identifier option:
  //
  //     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |        OPTION_CLIENTID        |          option-len           |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    .                                                               .
  //    .                              DUID                             .
  //    .                        (variable length)                      .
  //    .                                                               .
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //
  //
  //  The format of DUID-LLT:
  //
  //     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |          Duid type (1)        |    hardware type (16 bits)    |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |                        time (32 bits)                         |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    .                                                               .
  //    .             link-layer address (variable length)              .
  //    .                                                               .
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //

  //
  // sizeof (option-len + Duid-type + hardware-type + time) = 10 bytes
  //
  Duid = AllocateZeroPool (10 + Mode->HwAddressSize);
  if (Duid == NULL) {
    return NULL;
  }

  //
  // sizeof (Duid-type + hardware-type + time) = 8 bytes
  //
  Duid->Length = (UINT16) (Mode->HwAddressSize + 8);

  //
  // Set the Duid-type, hardware-type, time and copy the hardware address.
  //
  WriteUnaligned16 ((UINT16 *) (Duid->Duid), HTONS (Dhcp6DuidTypeLlt));
  WriteUnaligned16 ((UINT16 *) (Duid->Duid + 2), HTONS (NET_IFTYPE_ETHERNET));
  WriteUnaligned32 ((UINT32 *) (Duid->Duid + 4), HTONL (Stamp));

  CopyMem (Duid->Duid + 8, &Mode->CurrentAddress, Mode->HwAddressSize);

  Status = gRT->SetVariable (
                  L"ClientId",
                  &gEfiDhcp6ServiceBindingProtocolGuid,
                  (EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS),
                  Duid->Length + 2,
                  (VOID *) Duid
                  );
  ASSERT_EFI_ERROR (Status);

  return Duid;
}


/**
  Copy the Dhcp6 configure data.

  @param[in]  DstCfg        The pointer to the destination configure data.
  @param[in]  SorCfg        The pointer to the source configure data.

  @retval EFI_SUCCESS           Copy the content from SorCfg from DstCfg successfully.
  @retval EFI_OUT_OF_RESOURCES  Required system resources could not be allocated.

**/
EFI_STATUS
Dhcp6CopyConfigData (
  IN EFI_DHCP6_CONFIG_DATA      *DstCfg,
  IN EFI_DHCP6_CONFIG_DATA      *SorCfg
  )
{
  UINTN                     Index;
  UINTN                     OptionListSize;
  UINTN                     OptionSize;

  CopyMem (DstCfg, SorCfg, sizeof (EFI_DHCP6_CONFIG_DATA));

  //
  // Allocate another buffer for solicitretransmission, and copy it.
  //
  if (SorCfg->SolicitRetransmission != NULL) {

    DstCfg->SolicitRetransmission = AllocateZeroPool (sizeof (EFI_DHCP6_RETRANSMISSION));

    if (DstCfg->SolicitRetransmission == NULL) {
      //
      // Error will be handled out of this function.
      //
      return EFI_OUT_OF_RESOURCES;
    }

    CopyMem (
      DstCfg->SolicitRetransmission,
      SorCfg->SolicitRetransmission,
      sizeof (EFI_DHCP6_RETRANSMISSION)
      );
  }

  if (SorCfg->OptionList != NULL && SorCfg->OptionCount != 0) {

    OptionListSize     = SorCfg->OptionCount * sizeof (EFI_DHCP6_PACKET_OPTION *);
    DstCfg->OptionList = AllocateZeroPool (OptionListSize);

    if (DstCfg->OptionList == NULL) {
      //
      // Error will be handled out of this function.
      //
      return EFI_OUT_OF_RESOURCES;
    }

    for (Index = 0; Index < SorCfg->OptionCount; Index++) {

      OptionSize                = NTOHS (SorCfg->OptionList[Index]->OpLen) + 4;
      DstCfg->OptionList[Index] = AllocateZeroPool (OptionSize);

      if (DstCfg->OptionList[Index] == NULL) {
        //
        // Error will be handled out of this function.
        //
        return EFI_OUT_OF_RESOURCES;
      }

      CopyMem (
        DstCfg->OptionList[Index],
        SorCfg->OptionList[Index],
        OptionSize
        );
    }
  }

  return EFI_SUCCESS;
}


/**
  Clean up the configure data.

  @param[in, out]  CfgData       The pointer to the configure data.

**/
VOID
Dhcp6CleanupConfigData (
  IN OUT EFI_DHCP6_CONFIG_DATA       *CfgData
  )
{
  UINTN                          Index;

  ASSERT (CfgData != NULL);
  //
  // Clean up all fields in config data including the reference buffers, but do
  // not free the config data buffer itself.
  //
  if (CfgData->OptionList != NULL) {
    for (Index = 0; Index < CfgData->OptionCount; Index++) {
      if (CfgData->OptionList[Index] != NULL) {
        FreePool (CfgData->OptionList[Index]);
      }
    }
    FreePool (CfgData->OptionList);
  }

  if (CfgData->SolicitRetransmission != NULL) {
    FreePool (CfgData->SolicitRetransmission);
  }

  ZeroMem (CfgData, sizeof (EFI_DHCP6_CONFIG_DATA));
}


/**
  Clean up the mode data.

  @param[in, out]  ModeData      The pointer to the mode data.

**/
VOID
Dhcp6CleanupModeData (
  IN OUT EFI_DHCP6_MODE_DATA        *ModeData
  )
{
  ASSERT (ModeData != NULL);
  //
  // Clean up all fields in mode data including the reference buffers, but do
  // not free the mode data buffer itself.
  //
  if (ModeData->ClientId != NULL) {
    FreePool (ModeData->ClientId);
  }

  if (ModeData->Ia != NULL) {

    if (ModeData->Ia->ReplyPacket != NULL) {
      FreePool (ModeData->Ia->ReplyPacket);
    }
    FreePool (ModeData->Ia);
  }

  ZeroMem (ModeData, sizeof (EFI_DHCP6_MODE_DATA));
}


/**
  Calculate the expire time by the algorithm defined in rfc.

  @param[in]  Base          The base value of the time.
  @param[in]  IsFirstRt     If TRUE, it is the first time to calculate expire time.
  @param[in]  NeedSigned    If TRUE, the the signed factor is needed.

  @return     Expire        The calculated result for the new expire time.

**/
UINT32
Dhcp6CalculateExpireTime (
  IN UINT32                 Base,
  IN BOOLEAN                IsFirstRt,
  IN BOOLEAN                NeedSigned
  )
{
  EFI_TIME                  Time;
  BOOLEAN                   Signed;
  UINT32                    Seed;
  UINT32                    Expire;

  //
  // Take the 10bits of microsecond in system time as a uniform distribution.
  // Take the 10th bit as a flag to determine it's signed or not.
  //
  gRT->GetTime (&Time, NULL);
  Seed   = ((Time.Nanosecond >> 10) & DHCP6_10_BIT_MASK);
  Signed = (BOOLEAN) ((((Time.Nanosecond >> 9) & 0x01) != 0) ? TRUE : FALSE);
  Signed = (BOOLEAN) (NeedSigned ? Signed : FALSE);

  //
  // Calculate expire by the following algo:
  //   1. base + base * (-0.1 ~ 0) for the first solicit
  //   2. base + base * (-0.1 ~ 0.1) for the first other messages
  //   3. 2 * base + base * (-0.1 ~ 0.1) for the subsequent all messages
  //   4. base + base * (-0.1 ~ 0) for the more than mrt timeout
  //
  // The (Seed / 0x3ff / 10) is used to a random range (0, 0.1).
  //
  if (IsFirstRt && Signed) {

    Expire = Base - (UINT32) (Base * Seed / DHCP6_10_BIT_MASK / 10);

  } else if (IsFirstRt && !Signed) {

    Expire = Base + (UINT32) (Base * Seed / DHCP6_10_BIT_MASK / 10);

  } else if (!IsFirstRt && Signed) {

    Expire = 2 * Base - (UINT32) (Base * Seed / DHCP6_10_BIT_MASK / 10);

  } else {

    Expire = 2 * Base + (UINT32) (Base * Seed / DHCP6_10_BIT_MASK / 10);
  }

  Expire = (Expire != 0) ? Expire : 1;

  return Expire;
}


/**
  Calculate the lease time by the algorithm defined in rfc.

  @param[in]  IaCb          The pointer to the Ia control block.

**/
VOID
Dhcp6CalculateLeaseTime (
  IN DHCP6_IA_CB              *IaCb
  )
{
  EFI_DHCP6_IA_ADDRESS        *IaAddr;
  UINT32                      MinLt;
  UINT32                      MaxLt;
  UINTN                       Index;

  ASSERT (IaCb->Ia->IaAddressCount > 0);

  MinLt    = (UINT32) (-1);
  MaxLt    = 0;

  //
  // Calculate minlt as min of all valid life time, and maxlt as max of all
  // valid life time.
  //
  for (Index = 0; Index < IaCb->Ia->IaAddressCount; Index++) {
    IaAddr = IaCb->Ia->IaAddress + Index * sizeof (EFI_DHCP6_IA_ADDRESS);
    MinLt  = MIN (MinLt, IaAddr->ValidLifetime);
    MaxLt  = MAX (MinLt, IaAddr->ValidLifetime);
  }

  //
  // Take 50% minlt as t1, and 80% maxlt as t2 if Dhcp6 server doesn't offer
  // such information.
  //
  IaCb->T1            = (IaCb->T1 != 0) ? IaCb->T1 : (UINT32)(MinLt * 5 / 10);
  IaCb->T2            = (IaCb->T2 != 0) ? IaCb->T2 : (UINT32)(MinLt * 8 / 10);
  IaCb->AllExpireTime = MaxLt;
  IaCb->LeaseTime     = 0;
}


/**
  Check whether the addresses are all included by the configured Ia.

  @param[in]  Ia            The pointer to the Ia.
  @param[in]  AddressCount  The number of addresses.
  @param[in]  Addresses     The pointer to the addresses buffer.

  @retval EFI_SUCCESS         The addresses are all included by the configured IA.
  @retval EFI_NOT_FOUND       The addresses are not included by the configured IA.

**/
EFI_STATUS
Dhcp6CheckAddress (
  IN EFI_DHCP6_IA             *Ia,
  IN UINT32                   AddressCount,
  IN EFI_IPv6_ADDRESS         *Addresses
  )
{
  UINTN                       Index1;
  UINTN                       Index2;
  BOOLEAN                     Found;

  //
  // Check whether the addresses are all included by the configured IA. And it
  // will return success if address count is zero, which means all addresses.
  //
  for (Index1 = 0; Index1 < AddressCount; Index1++) {

    Found = FALSE;

    for (Index2 = 0; Index2 < Ia->IaAddressCount; Index2++) {

      if (CompareMem (
            &Addresses[Index1],
            &Ia->IaAddress[Index2],
            sizeof (EFI_IPv6_ADDRESS)
            ) == 0) {

        Found = TRUE;
        break;
      }
    }

    if (!Found) {
      return EFI_NOT_FOUND;
    }
  }

  return EFI_SUCCESS;
}


/**
  Deprive the addresses from current Ia, and generate another eliminated Ia.

  @param[in]  Ia            The pointer to the Ia.
  @param[in]  AddressCount  The number of addresses.
  @param[in]  Addresses     The pointer to the addresses buffer.

  @retval     NULL          If it failed to generate the deprived Ia.
  @retval     others        The pointer to the deprived Ia.

**/
EFI_DHCP6_IA *
Dhcp6DepriveAddress (
  IN EFI_DHCP6_IA             *Ia,
  IN UINT32                   AddressCount,
  IN EFI_IPv6_ADDRESS         *Addresses
  )
{
  EFI_DHCP6_IA                *IaCopy;
  UINTN                       IaCopySize;
  UINTN                       Index1;
  UINTN                       Index2;
  BOOLEAN                     Found;

  if (AddressCount == 0) {
    //
    // It means release all Ia addresses if address count is zero.
    //
    AddressCount = Ia->IaAddressCount;
  }

  ASSERT (AddressCount != 0);

  IaCopySize = sizeof (EFI_DHCP6_IA) + (AddressCount - 1) * sizeof (EFI_DHCP6_IA_ADDRESS);
  IaCopy     = AllocateZeroPool (IaCopySize);

  if (IaCopy == NULL) {
    return NULL;
  }

  if (AddressCount == Ia->IaAddressCount) {
    //
    // If release all Ia addresses, just copy the configured Ia and then set
    // its address count as zero.
    // We may decline/release part of addresses at the begining. So it's a
    // forwarding step to update address infor for decline/release, while the
    // other infor such as Ia state will be updated when receiving reply.
    //
    CopyMem (IaCopy, Ia, IaCopySize);
    Ia->IaAddressCount = 0;
    return IaCopy;
  }

  CopyMem (IaCopy, Ia, sizeof (EFI_DHCP6_IA));

  //
  // Move the addresses from the Ia of instance to the deprived Ia.
  //
  for (Index1 = 0; Index1 < AddressCount; Index1++) {

    Found = FALSE;

    for (Index2 = 0; Index2 < Ia->IaAddressCount; Index2++) {

      if (CompareMem (
            &Addresses[Index1],
            &Ia->IaAddress[Index2],
            sizeof (EFI_IPv6_ADDRESS)
            ) == 0) {
        //
        // Copy the deprived address to the copy of Ia
        //
        CopyMem (
          &IaCopy->IaAddress[Index1],
          &Ia->IaAddress[Index2],
          sizeof (EFI_DHCP6_IA_ADDRESS)
          );
        //
        // Delete the deprived address from the instance Ia
        //
        if (Index2 + 1 < Ia->IaAddressCount) {
          CopyMem (
            &Ia->IaAddress[Index2],
            &Ia->IaAddress[Index2 + 1],
            (Ia->IaAddressCount - Index2 - 1) * sizeof (EFI_DHCP6_IA_ADDRESS)
            );
        }
        Found = TRUE;
        break;
      }
    }
    ASSERT (Found == TRUE);
  }

  Ia->IaAddressCount    -= AddressCount;
  IaCopy->IaAddressCount = AddressCount;

  return IaCopy;
}


/**
  The dummy ext buffer free callback routine.

  @param[in]  Arg           The pointer to the parameter.

**/
VOID
EFIAPI
Dhcp6DummyExtFree (
  IN VOID                      *Arg
  )
{
}


/**
  The callback routine once message transmitted.

  @param[in]  Udp6Wrap      The pointer to the received net buffer.
  @param[in]  EndPoint      The pointer to the udp end point.
  @param[in]  IoStatus      The return status from udp io.
  @param[in]  Context       The opaque parameter to the function.

**/
VOID
EFIAPI
Dhcp6OnTransmitted (
  IN NET_BUF                   *Wrap,
  IN UDP_END_POINT             *EndPoint,
  IN EFI_STATUS                IoStatus,
  IN VOID                      *Context
  )
{
  NetbufFree (Wrap);
}


/**
  Append the option to Buf, and move Buf to the end.

  @param[in, out] Buf           The pointer to the buffer.
  @param[in]      OptType       The option type.
  @param[in]      OptLen        The length of option contents.
  @param[in]      Data          The pointer to the option content.

  @return         Buf           The position to append the next option.

**/
UINT8 *
Dhcp6AppendOption (
  IN OUT UINT8               *Buf,
  IN     UINT16              OptType,
  IN     UINT16              OptLen,
  IN     UINT8               *Data
  )
{
  //
  //  The format of Dhcp6 option:
  //
  //     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |          option-code          |   option-len (option data)    |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |                          option-data                          |
  //    |                      (option-len octets)                      |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //

  ASSERT (OptLen != 0);

  WriteUnaligned16 ((UINT16 *) Buf, OptType);
  Buf            += 2;
  WriteUnaligned16 ((UINT16 *) Buf, OptLen);
  Buf            += 2;
  CopyMem (Buf, Data, NTOHS (OptLen));
  Buf            += NTOHS (OptLen);

  return Buf;
}


/**
  Append the appointed Ia option to Buf, and move Buf to the end.

  @param[in, out] Buf           The pointer to the position to append.
  @param[in]      Ia            The pointer to the Ia.
  @param[in]      T1            The time of T1.
  @param[in]      T2            The time of T2.

  @return         Buf           The position to append the next Ia option.

**/
UINT8 *
Dhcp6AppendIaOption (
  IN OUT UINT8                  *Buf,
  IN     EFI_DHCP6_IA           *Ia,
  IN     UINT32                 T1,
  IN     UINT32                 T2
  )
{
  UINT8                     *AddrOpt;
  UINT16                    *Len;
  UINTN                     Index;
  UINT16                    Length;

  //
  //  The format of IA_NA and IA_TA option:
  //
  //     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |          OPTION_IA_NA         |          option-len           |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |                        IAID (4 octets)                        |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |                        T1 (only for IA_NA)                    |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |                        T2 (only for IA_NA)                    |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |                                                               |
  //    .                  IA_NA-options/IA_TA-options                  .
  //    .                                                               .
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //

  //
  // Fill the value of Ia option type
  //
  WriteUnaligned16 ((UINT16 *) Buf, HTONS (Ia->Descriptor.Type));
  Buf                     += 2;

  //
  // Fill the len of Ia option later, keep the pointer first
  //
  Len                      = (UINT16 *) Buf;
  Buf                     += 2;

  //
  // Fill the value of iaid
  //
  WriteUnaligned32 ((UINT32 *) Buf, HTONL (Ia->Descriptor.IaId));
  Buf                     += 4;

  //
  // Fill the value of t1 and t2 if iana, keep it 0xffffffff if no specified.
  //
  if (Ia->Descriptor.Type == Dhcp6OptIana) {
    WriteUnaligned32 ((UINT32 *) Buf, ((T1 != 0) ? T1 : 0xffffffff));
    Buf                   += 4;
    WriteUnaligned32 ((UINT32 *) Buf, ((T2 != 0) ? T2 : 0xffffffff));
    Buf                   += 4;
  }

  //
  // Fill all the addresses belong to the Ia
  //
  for (Index = 0; Index < Ia->IaAddressCount; Index++) {

     AddrOpt = (UINT8 *) Ia->IaAddress + Index * sizeof (EFI_DHCP6_IA_ADDRESS);
     Length  = HTONS ((UINT16) sizeof (EFI_DHCP6_IA_ADDRESS));
     Buf     = Dhcp6AppendOption (
                 Buf,
                 HTONS (Dhcp6OptIaAddr),
                 Length,
                 AddrOpt
                 );
  }

  //
  // Fill the value of Ia option length
  //
  *Len = HTONS ((UINT16) (Buf - (UINT8 *) Len - 2));

  return Buf;
}

/**
  Append the appointed Elapsed time option to Buf, and move Buf to the end.

  @param[in, out] Buf           The pointer to the position to append.
  @param[in]      Instance      The pointer to the Dhcp6 instance.
  @param[out]     Elapsed       The pointer to the elapsed time value in
                                  the generated packet.

  @return         Buf           The position to append the next Ia option.

**/
UINT8 *
Dhcp6AppendETOption (
  IN OUT UINT8                  *Buf,
  IN     DHCP6_INSTANCE         *Instance,
  OUT    UINT16                 **Elapsed
  )
{
  //
  //  The format of elapsed time option:
  //
  //   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //  |      OPTION_ELAPSED_TIME      |           option-len          |
  //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //  |          elapsed-time         |
  //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //

  //
  // Fill the value of elapsed-time option type.
  //
  WriteUnaligned16 ((UINT16 *) Buf, HTONS (Dhcp6OptElapsedTime));
  Buf                     += 2;

  //
  // Fill the len of elapsed-time option, which is fixed.
  //
  WriteUnaligned16 ((UINT16 *) Buf, HTONS(2));
  Buf                     += 2;

  //
  // Fill in elapsed time value with 0 value for now.  The actual value is
  // filled in later just before the packet is transmitted.
  //
  WriteUnaligned16 ((UINT16 *) Buf, HTONS(0));
  *Elapsed                  = (UINT16 *) Buf;
  Buf                     += 2;

  return Buf;
}

/**
  Set the elapsed time based on the given instance and the pointer to the
  elapsed time option.

  @param[in]      Elapsed       The pointer to the position to append.
  @param[in]      Instance      The pointer to the Dhcp6 instance.

**/
VOID
SetElapsedTime (
  IN     UINT16                 *Elapsed,
  IN     DHCP6_INSTANCE         *Instance
  )
{
  EFI_TIME          Time;
  UINT64            CurrentStamp;
  UINT64            ElapsedTimeValue;

  //
  // Generate a time stamp of the centiseconds from 2000/1/1, assume 30day/month.
  //
  gRT->GetTime (&Time, NULL);
  CurrentStamp = (UINT64)
    (
      ((((((Time.Year - 2000) * 360 +
       (Time.Month - 1)) * 30 +
       (Time.Day - 1)) * 24 + Time.Hour) * 60 +
       Time.Minute) * 60 + Time.Second) * 100
       + DivU64x32(Time.Nanosecond, 10000000)
    );

  //
  // Sentinel value of 0 means that this is the first DHCP packet that we are
  // sending and that we need to initialize the value.  First DHCP Solicit
  // gets 0 elapsed-time.  Otherwise, calculate based on StartTime.
  //
  if (Instance->StartTime == 0) {
    ElapsedTimeValue = 0;
    Instance->StartTime = CurrentStamp;
  } else {
    ElapsedTimeValue = CurrentStamp - Instance->StartTime;

    //
    // If elapsed time cannot fit in two bytes, set it to 0xffff.
    //
    if (ElapsedTimeValue > 0xffff) {
      ElapsedTimeValue = 0xffff;
    }
  }
  WriteUnaligned16 (Elapsed, HTONS((UINT16) ElapsedTimeValue));
}


/**
  Seek the address of the first byte of the option header.

  @param[in]  Buf           The pointer to the buffer.
  @param[in]  SeekLen       The length to seek.
  @param[in]  OptType       The option type.

  @retval     NULL          If it failed to seek the option.
  @retval     others        The position to the option.

**/
UINT8 *
Dhcp6SeekOption (
  IN UINT8           *Buf,
  IN UINT32          SeekLen,
  IN UINT16          OptType
  )
{
  UINT8              *Cursor;
  UINT8              *Option;
  UINT16             DataLen;
  UINT16             OpCode;

  Option = NULL;
  Cursor = Buf;

  //
  // The format of Dhcp6 option refers to Dhcp6AppendOption().
  //
  while (Cursor < Buf + SeekLen) {
    OpCode = ReadUnaligned16 ((UINT16 *) Cursor);
    if (OpCode == HTONS (OptType)) {
      Option = Cursor;
      break;
    }
    DataLen = NTOHS (ReadUnaligned16 ((UINT16 *) (Cursor + 2)));
    Cursor += (DataLen + 4);
  }

  return Option;
}


/**
  Seek the address of the first byte of the Ia option header.

  @param[in]  Buf           The pointer to the buffer.
  @param[in]  SeekLen       The length to seek.
  @param[in]  IaDesc        The pointer to the Ia descriptor.

  @retval     NULL          If it failed to seek the Ia option.
  @retval     others        The position to the Ia option.

**/
UINT8 *
Dhcp6SeekIaOption (
  IN UINT8                    *Buf,
  IN UINT32                   SeekLen,
  IN EFI_DHCP6_IA_DESCRIPTOR  *IaDesc
  )
{
  UINT8              *Cursor;
  UINT8              *Option;
  UINT16             DataLen;
  UINT16             OpCode;
  UINT32             IaId;

  //
  // The format of IA_NA and IA_TA option refers to Dhcp6AppendIaOption().
  //
  Option = NULL;
  Cursor = Buf;

  while (Cursor < Buf + SeekLen) {
    OpCode = ReadUnaligned16 ((UINT16 *) Cursor);
    IaId   = ReadUnaligned32 ((UINT32 *) (Cursor + 4));
    if (OpCode == HTONS (IaDesc->Type) && IaId == HTONL (IaDesc->IaId)) {
      Option = Cursor;
      break;
    }
    DataLen = NTOHS (ReadUnaligned16 ((UINT16 *) (Cursor + 2)));
    Cursor += (DataLen + 4);
  }

  return Option;
}


/**
  Parse the address option and update the address infomation.

  @param[in]      IaInnerOpt    The pointer to the buffer.
  @param[in]      IaInnerLen    The length to parse.
  @param[out]     AddrNum       The number of addresses.
  @param[in, out] AddrBuf       The pointer to the address buffer.

**/
VOID
Dhcp6ParseAddrOption (
  IN     UINT8                   *IaInnerOpt,
  IN     UINT16                  IaInnerLen,
     OUT UINT32                  *AddrNum,
  IN OUT EFI_DHCP6_IA_ADDRESS    *AddrBuf
  )
{
  UINT8                       *Cursor;
  UINT16                      DataLen;
  UINT16                      OpCode;
  UINT32                      ValidLt;

  //
  //  The format of the IA Address option:
  //
  //     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |          OPTION_IAADDR        |          option-len           |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |                                                               |
  //    |                         IPv6 address                          |
  //    |                                                               |
  //    |                                                               |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |                      preferred-lifetime                       |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    |                        valid-lifetime                         |
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //    .                                                               .
  //    .                        IAaddr-options                         .
  //    .                                                               .
  //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  //

  //
  //  Two usage model:
  //
  //    1. Pass addrbuf == null, to get the addrnum over the Ia inner options.
  //    2. Pass addrbuf != null, to resolve the addresses over the Ia inner
  //       options to the addrbuf.
  //

  Cursor   = IaInnerOpt;
  *AddrNum = 0;

  while (Cursor < IaInnerOpt + IaInnerLen) {
    //
    // Count the Ia address option with non-0 valid time.
    //
    OpCode  = ReadUnaligned16 ((UINT16 *) Cursor);
    ValidLt = ReadUnaligned32 ((UINT32 *) (Cursor + 24));
    if (OpCode == HTONS (Dhcp6OptIaAddr) && ValidLt != 0) {

      if (AddrBuf != NULL) {
        CopyMem (AddrBuf, Cursor + 4, sizeof (EFI_DHCP6_IA_ADDRESS));
        AddrBuf->PreferredLifetime = NTOHL (AddrBuf->PreferredLifetime);
        AddrBuf->ValidLifetime     = NTOHL (AddrBuf->ValidLifetime);
        AddrBuf = (EFI_DHCP6_IA_ADDRESS *) ((UINT8 *) AddrBuf + sizeof (EFI_DHCP6_IA_ADDRESS));
      }

      (*AddrNum)++;
    }
    DataLen = NTOHS (ReadUnaligned16 ((UINT16 *) (Cursor + 2)));
    Cursor += (DataLen + 4);
  }
}


/**
  Create a control blcok for the Ia according to the corresponding options.

  @param[in]  Instance              The pointer to DHCP6 Instance.
  @param[in]  IaInnerOpt            The pointer to the inner options in the Ia option.
  @param[in]  IaInnerLen            The length of all the inner options in the Ia option.
  @param[in]  T1                    T1 time in the Ia option.
  @param[in]  T2                    T2 time in the Ia option.

  @retval     EFI_NOT_FOUND         No valid IA option is found.
  @retval     EFI_SUCCESS           Create an IA control block successfully.
  @retval     EFI_OUT_OF_RESOURCES  Required system resources could not be allocated.

**/
EFI_STATUS
Dhcp6GenerateIaCb (
  IN  DHCP6_INSTANCE           *Instance,
  IN  UINT8                    *IaInnerOpt,
  IN  UINT16                   IaInnerLen,
  IN  UINT32                   T1,
  IN  UINT32                   T2
  )
{
  UINT32                       AddrNum;
  UINT32                       IaSize;
  EFI_DHCP6_IA                 *Ia;

  if (Instance->IaCb.Ia == NULL) {
    return EFI_NOT_FOUND;
  }

  //
  // Calculate the number of addresses for this Ia, excluding the addresses with
  // the value 0 of valid lifetime.
  //
  Dhcp6ParseAddrOption (IaInnerOpt, IaInnerLen, &AddrNum, NULL);

  if (AddrNum == 0) {
    return EFI_NOT_FOUND;
  }

  //
  // Allocate for new IA.
  //
  IaSize = sizeof (EFI_DHCP6_IA) + (AddrNum - 1) * sizeof (EFI_DHCP6_IA_ADDRESS);
  Ia = AllocateZeroPool (IaSize);

  if (Ia == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  //
  // Fill up this new IA fields.
  //
  Ia->State          = Instance->IaCb.Ia->State;
  Ia->IaAddressCount = AddrNum;
  CopyMem (&Ia->Descriptor, &Instance->Config->IaDescriptor, sizeof (EFI_DHCP6_IA_DESCRIPTOR));
  Dhcp6ParseAddrOption (IaInnerOpt, IaInnerLen, &AddrNum, Ia->IaAddress);

  //
  // Free original IA resource.
  //
  if (Instance->IaCb.Ia->ReplyPacket != NULL) {
    FreePool (Instance->IaCb.Ia->ReplyPacket);
  }
  FreePool (Instance->IaCb.Ia);


  ZeroMem (&Instance->IaCb, sizeof (DHCP6_IA_CB));

  //
  // Update IaCb to use new IA.
  //
  Instance->IaCb.Ia   = Ia;

  //

 // Fill in IaCb fields. Such as T1, T2, AllExpireTime and LeaseTime.
  //
  Instance->IaCb.T1 = T1;
  Instance->IaCb.T2 = T2;
  Dhcp6CalculateLeaseTime (&Instance->IaCb);

  return EFI_SUCCESS;
}


/**
  Cache the current IA configuration information.

  @param[in] Instance           The pointer to DHCP6 Instance.

  @retval EFI_SUCCESS           Cache the current IA successfully.
  @retval EFI_OUT_OF_RESOURCES  Required system resources could not be allocated.

**/
EFI_STATUS
Dhcp6CacheIa (
  IN DHCP6_INSTANCE           *Instance
  )
{
  UINTN                        IaSize;
  EFI_DHCP6_IA                 *Ia;

  Ia = Instance->IaCb.Ia;

  if ((Instance->CacheIa == NULL) && (Ia != NULL)) {
    //
    // Cache the current IA.
    //
    IaSize = sizeof (EFI_DHCP6_IA) + (Ia->IaAddressCount - 1) * sizeof (EFI_DHCP6_IA_ADDRESS);

    Instance->CacheIa = AllocateZeroPool (IaSize);
    if (Instance->CacheIa == NULL) {
      return EFI_OUT_OF_RESOURCES;
    }
    CopyMem (Instance->CacheIa, Ia, IaSize);
  }
  return EFI_SUCCESS;
}

/**
  Append CacheIa to the currrent IA. Meanwhile, clear CacheIa.ValidLifetime to 0.

  @param[in]  Instance            The pointer to DHCP6 instance.

**/
VOID
Dhcp6AppendCacheIa (
  IN DHCP6_INSTANCE           *Instance
  )
{
  UINT8                        *Ptr;
  UINTN                        Index;
  UINTN                        IaSize;
  UINTN                        NewIaSize;
  EFI_DHCP6_IA                 *Ia;
  EFI_DHCP6_IA                 *NewIa;
  EFI_DHCP6_IA                 *CacheIa;

  Ia      = Instance->IaCb.Ia;
  CacheIa = Instance->CacheIa;

  if ((CacheIa != NULL) && (CacheIa->IaAddressCount != 0)) {
    //
    // There are old addresses existing. Merge with current addresses.
    //
    NewIaSize = sizeof (EFI_DHCP6_IA) + (Ia->IaAddressCount + CacheIa->IaAddressCount - 1) * sizeof (EFI_DHCP6_IA_ADDRESS);
    NewIa     = AllocateZeroPool (NewIaSize);
    if (NewIa == NULL) {
      return;
    }

    IaSize = sizeof (EFI_DHCP6_IA) + (Ia->IaAddressCount - 1) * sizeof (EFI_DHCP6_IA_ADDRESS);
    CopyMem (NewIa, Ia, IaSize);

    //
    // Clear old address.ValidLifetime
    //
    for (Index = 0; Index < CacheIa->IaAddressCount; Index++) {
      CacheIa->IaAddress[Index].ValidLifetime  = 0;
    }

    NewIa->IaAddressCount += CacheIa->IaAddressCount;
    Ptr   = (UINT8*)&NewIa->IaAddress[Ia->IaAddressCount];
    CopyMem (Ptr, CacheIa->IaAddress, CacheIa->IaAddressCount * sizeof (EFI_DHCP6_IA_ADDRESS));

    //
    // Migrate to the NewIa and free previous.
    //
    FreePool (Instance->CacheIa);
    FreePool (Instance->IaCb.Ia);
    Instance->CacheIa  = NULL;
    Instance->IaCb.Ia  = NewIa;
  }
}