summaryrefslogtreecommitdiffstats
path: root/wiretap/netmon.c
blob: 861b1f908623e822ae31395990c5ed7c8feca85f (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
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
/* netmon.c
 *
 * Wiretap Library
 * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"
#include <errno.h>
#include <string.h>
#include <wsutil/unicode-utils.h>
#include "wtap-int.h"
#include "file_wrappers.h"
#include "atm.h"
#include "pcap-encap.h"
#include "netmon.h"

/* The file at
 *
 *	ftp://ftp.microsoft.com/developr/drg/cifs/cifs/Bhfile.zip
 *
 * contains "STRUCT.H", which declares the typedef CAPTUREFILE_HEADER
 * for the header of a Microsoft Network Monitor 1.x capture file.
 *
 * The help files for Network Monitor 3.x document the 2.x file format.
 */

/* Capture file header, *including* magic number, is padded to 128 bytes. */
#define	CAPTUREFILE_HEADER_SIZE	128

/* Magic number size, for both 1.x and 2.x. */
#define MAGIC_SIZE	4

/* Magic number in Network Monitor 1.x files. */
static const char netmon_1_x_magic[MAGIC_SIZE] = {
	'R', 'T', 'S', 'S'
};

/* Magic number in Network Monitor 2.x files. */
static const char netmon_2_x_magic[MAGIC_SIZE] = {
	'G', 'M', 'B', 'U'
};

/* Network Monitor file header (minus magic number). */
struct netmon_hdr {
	guint8	ver_minor;	/* minor version number */
	guint8	ver_major;	/* major version number */
	guint16	network;	/* network type */
	guint16	ts_year;	/* year of capture start */
	guint16	ts_month;	/* month of capture start (January = 1) */
	guint16	ts_dow;		/* day of week of capture start (Sun = 0) */
	guint16	ts_day;		/* day of month of capture start */
	guint16	ts_hour;	/* hour of capture start */
	guint16	ts_min;		/* minute of capture start */
	guint16	ts_sec;		/* second of capture start */
	guint16	ts_msec;	/* millisecond of capture start */
	guint32	frametableoffset;	/* frame index table offset */
	guint32	frametablelength;	/* frame index table size */
	guint32	userdataoffset;		/* user data offset */
	guint32	userdatalength;		/* user data size */
	guint32	commentdataoffset;	/* comment data offset */
	guint32	commentdatalength;	/* comment data size */
	guint32	processinfooffset;	/* offset to process info structure */
	guint32	processinfocount;	/* number of process info structures */
	guint32	networkinfooffset;	/* offset to network info structure */
	guint32	networkinfolength;	/* length of network info structure */
};

/* Network Monitor 1.x record header; not defined in STRUCT.H, but deduced by
 * looking at capture files. */
struct netmonrec_1_x_hdr {
	guint32	ts_delta;	/* time stamp - msecs since start of capture */
	guint16	orig_len;	/* actual length of packet */
	guint16	incl_len;	/* number of octets captured in file */
};

/*
 * Network Monitor 2.x record header, as documented in NetMon 3.x's
 * help files.
 */
struct netmonrec_2_x_hdr {
	guint64	ts_delta;	/* time stamp - usecs since start of capture */
	guint32	orig_len;	/* actual length of packet */
	guint32	incl_len;	/* number of octets captured in file */
};

/*
 * Network Monitor 2.1 and later record trailers; documented in the Network
 * Monitor 3.x help files, for 3.3 and later, although they don't clearly
 * state how the trailer format changes from version to version.
 *
 * Some fields are multi-byte integers, but they're not aligned on their
 * natural boundaries.
 */
struct netmonrec_2_1_trlr {
	guint8 network[2];		/* network type for this packet */
};

struct netmonrec_2_2_trlr {
	guint8 network[2];		/* network type for this packet */
	guint8 process_info_index[4];	/* index into the process info table */
};

struct netmonrec_2_3_trlr {
	guint8 network[2];		/* network type for this packet */
	guint8 process_info_index[4];	/* index into the process info table */
	guint8 utc_timestamp[8];	/* packet time stamp, as .1 us units since January 1, 1601, 00:00:00 UTC */
	guint8 timezone_index;		/* index of time zone information */
};

struct netmonrec_comment {
	guint32 numFramePerComment;	/* Currently, this is always set to 1. Each comment is attached to only one frame. */
	guint32 frameOffset;		/* Offset in the capture file table that indicates the beginning of the frame.  Key used to match comment with frame */
	guint8* title;			/* Comment title */
	guint32 descLength;		/* Number of bytes in the comment description. Must be at least zero. */
	guint8* description;		/* Comment description */
};

/* Just the first few fields of netmonrec_comment so it can be read sequentially from file */
struct netmonrec_comment_header {
	guint32 numFramePerComment;
	guint32 frameOffset;
	guint32 titleLength;
};

union ip_address {
	guint32 ipv4;
	ws_in6_addr ipv6;
};

struct netmonrec_process_info {
	guint8* path;				/* A Unicode string of length PathSize */
	guint32 iconSize;
	guint8* iconData;
	guint32 pid;
	guint16 localPort;
	guint16 remotePort;
	gboolean isIPv6;
	union ip_address localAddr;
	union ip_address remoteAddr;
};

/*
 * The link-layer header on ATM packets.
 */
struct netmon_atm_hdr {
	guint8	dest[6];	/* "Destination address" - what is it? */
	guint8	src[6];		/* "Source address" - what is it? */
	guint16	vpi;		/* VPI */
	guint16	vci;		/* VCI */
};

typedef struct {
	time_t  start_secs;
	guint32 start_nsecs;
	guint8  version_major;
	guint8  version_minor;
	guint32 *frame_table;
	guint32 frame_table_size;
	GHashTable* comment_table;
	GHashTable* process_info_table;
	guint current_frame;
} netmon_t;

/*
 * Maximum pathname length supported in the process table; the length
 * is in a 32-bit field, so we impose a limit to prevent attempts to
 * allocate too much memory.
 *
 * See
 *
 *    https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#maximum-path-length-limitation
 *
 * The NetMon 3.4 "Capture File Format" documentation says "PathSize must be
 * greater than 0, and less than MAX_PATH (260 characters)", but, as per that
 * link above, that limit has been raised in more recent systems.
 *
 * We pick a limit of 65536, as that should handle a path length of 32767
 * UTF-16 octet pairs plus a trailing NUL octet pair.
 */
#define MATH_PROCINFO_PATH_SIZE		65536

/*
 * XXX - at least in some NetMon 3.4 VPN captures, the per-packet
 * link-layer type is 0, but the packets have Ethernet headers.
 * We handle this by mapping 0 to WTAP_ENCAP_ETHERNET; should we,
 * instead, use the per-file link-layer type?
 */
static const int netmon_encap[] = {
	WTAP_ENCAP_ETHERNET,
	WTAP_ENCAP_ETHERNET,
	WTAP_ENCAP_TOKEN_RING,
	WTAP_ENCAP_FDDI_BITSWAPPED,
	WTAP_ENCAP_ATM_PDUS,	/* NDIS WAN - this is what's used for ATM */
	WTAP_ENCAP_UNKNOWN,	/* NDIS LocalTalk, but format 2.x uses it for IP-over-IEEE 1394 */
	WTAP_ENCAP_IEEE_802_11_NETMON,
				/* NDIS "DIX", but format 2.x uses it for 802.11 */
	WTAP_ENCAP_RAW_IP,	/* NDIS ARCNET raw, but format 2.x uses it for "Tunneling interfaces" */
	WTAP_ENCAP_RAW_IP,	/* NDIS ARCNET 878.2, but format 2.x uses it for "Wireless WAN" */
	WTAP_ENCAP_RAW_IP,	/* NDIS ATM (no, this is NOT used for ATM); format 2.x uses it for "Raw IP Frames" */
	WTAP_ENCAP_UNKNOWN,	/* NDIS Wireless WAN */
	WTAP_ENCAP_UNKNOWN	/* NDIS IrDA */
};
#define NUM_NETMON_ENCAPS (sizeof netmon_encap / sizeof netmon_encap[0])

/*
 * Special link-layer types.
 */
#define NETMON_NET_PCAP_BASE		0xE000
#define NETMON_NET_NETEVENT		0xFFE0
#define NETMON_NET_NETWORK_INFO_EX	0xFFFB
#define NETMON_NET_PAYLOAD_HEADER	0xFFFC
#define NETMON_NET_NETWORK_INFO		0xFFFD
#define NETMON_NET_DNS_CACHE		0xFFFE
#define NETMON_NET_NETMON_FILTER	0xFFFF

static gboolean netmon_read(wtap *wth, wtap_rec *rec, Buffer *buf,
    int *err, gchar **err_info, gint64 *data_offset);
static gboolean netmon_seek_read(wtap *wth, gint64 seek_off,
    wtap_rec *rec, Buffer *buf, int *err, gchar **err_info);
static gboolean netmon_read_atm_pseudoheader(FILE_T fh,
    union wtap_pseudo_header *pseudo_header, int *err, gchar **err_info);
static void netmon_close(wtap *wth);
static gboolean netmon_dump(wtap_dumper *wdh, const wtap_rec *rec,
    const guint8 *pd, int *err, gchar **err_info);
static gboolean netmon_dump_finish(wtap_dumper *wdh, int *err,
    gchar **err_info);

static int netmon_1_x_file_type_subtype = -1;
static int netmon_2_x_file_type_subtype = -1;

void register_netmon(void);

/*
 * Convert a counted UTF-16 string, which is probably also null-terminated
 * but is not guaranteed to be null-terminated (as it came from a file),
 * to a null-terminated UTF-8 string.
 */
static guint8 *
utf_16_to_utf_8(const guint8 *in, guint32 length)
{
	guint8 *result, *out;
	gunichar2 uchar2;
	gunichar uchar;
	size_t n_bytes;
	guint32 i;

	/*
	 * Get the length of the resulting UTF-8 string, and validate
	 * the input string in the process.
	 */
	n_bytes = 0;
	for (i = 0; i + 1 < length && (uchar2 = pletoh16(in + i)) != '\0';
	    i += 2) {
		if (IS_LEAD_SURROGATE(uchar2)) {
			/*
			 * Lead surrogate.  Must be followed by a trail
			 * surrogate.
			 */
			gunichar2 lead_surrogate;

			i += 2;
			if (i + 1 >= length) {
				/*
				 * Oops, string ends with a lead surrogate.
				 * Ignore this for now.
				 * XXX - insert "substitute" character?
				 * Report the error in some other fashion?
				 */
				break;
			}
			lead_surrogate = uchar2;
			uchar2 = pletoh16(in + i);
			if (uchar2 == '\0') {
				/*
				 * Oops, string ends with a lead surrogate.
				 * Ignore this for now.
				 * XXX - insert "substitute" character?
				 * Report the error in some other fashion?
				 */
				break;
			}
			if (IS_TRAIL_SURROGATE(uchar2)) {
				/* Trail surrogate. */
				uchar = SURROGATE_VALUE(lead_surrogate, uchar2);
				n_bytes += g_unichar_to_utf8(uchar, NULL);
			} else {
				/*
				 * Not a trail surrogate.
				 * Ignore the entire pair.
				 * XXX - insert "substitute" character?
				 * Report the error in some other fashion?
				 */
				;
			}
		} else {
			if (IS_TRAIL_SURROGATE(uchar2)) {
				/*
				 * Trail surrogate without a preceding
				 * lead surrogate.  Ignore it.
				 * XXX - insert "substitute" character?
				 * Report the error in some other fashion?
				 */
				;
			} else {
				/*
				 * Non-surrogate; just count it.
				 */
				n_bytes += g_unichar_to_utf8(uchar2, NULL);
			}
		}
	}

	/*
	 * Now allocate a buffer big enough for the UTF-8 string plus a
	 * trailing NUL, and generate the string.
	 */
	result = (guint8 *)g_malloc(n_bytes + 1);

	out = result;
	for (i = 0; i + 1 < length && (uchar2 = pletoh16(in + i)) != '\0';
	    i += 2) {
		if (IS_LEAD_SURROGATE(uchar2)) {
			/*
			 * Lead surrogate.  Must be followed by a trail
			 * surrogate.
			 */
			gunichar2 lead_surrogate;

			i += 2;
			if (i + 1 >= length) {
				/*
				 * Oops, string ends with a lead surrogate.
				 * Ignore this for now.
				 * XXX - insert "substitute" character?
				 * Report the error in some other fashion?
				 */
				break;
			}
			lead_surrogate = uchar2;
			uchar2 = pletoh16(in + i);
			if (uchar2 == '\0') {
				/*
				 * Oops, string ends with a lead surrogate.
				 * Ignore this for now.
				 * XXX - insert "substitute" character?
				 * Report the error in some other fashion?
				 */
				break;
			}
			if (IS_TRAIL_SURROGATE(uchar2)) {
				/* Trail surrogate. */
				uchar = SURROGATE_VALUE(lead_surrogate, uchar2);
				out += g_unichar_to_utf8(uchar, out);
			} else {
				/*
				 * Not a trail surrogate.
				 * Ignore the entire pair.
				 * XXX - insert "substitute" character?
				 * Report the error in some other fashion?
				 */
				;
			}
		} else {
			if (IS_TRAIL_SURROGATE(uchar2)) {
				/*
				 * Trail surrogate without a preceding
				 * lead surrogate.  Ignore it.
				 * XXX - insert "substitute" character?
				 * Report the error in some other fashion?
				 */
				;
			} else {
				/*
				 * Non-surrogate; just count it.
				 */
				out += g_unichar_to_utf8(uchar2, out);
			}
		}
	}
	*out = '\0';

	/*
	 * XXX - if i < length, this means we were handed an odd
	 * number of bytes, so it was not a valid UTF-16 string.
	 */
	return result;
}


static void netmonrec_comment_destroy(gpointer key) {
	struct netmonrec_comment *comment = (struct netmonrec_comment*) key;

	g_free(comment->title);
	g_free(comment->description);
	g_free(comment);
}

static void netmonrec_process_info_destroy(gpointer key) {
	struct netmonrec_process_info *process_info = (struct netmonrec_process_info*) key;

	g_free(process_info->path);
	g_free(process_info->iconData);
	g_free(process_info);
}

wtap_open_return_val netmon_open(wtap *wth, int *err, gchar **err_info)
{
	char magic[MAGIC_SIZE];
	struct netmon_hdr hdr;
	int file_type;
	struct tm tm;
	guint32 frame_table_offset;
	guint32 frame_table_length;
	guint32 frame_table_size;
	guint32 *frame_table;
	guint32 comment_table_offset, process_info_table_offset;
	guint32 comment_table_size, process_info_table_count;
	GHashTable *comment_table, *process_info_table;
	struct netmonrec_comment* comment_rec;
	gint64 file_size = wtap_file_size(wth, err);
#if G_BYTE_ORDER == G_BIG_ENDIAN
	unsigned int i;
#endif
	netmon_t *netmon;

	/* Read in the string that should be at the start of a Network
	 * Monitor file */
	if (!wtap_read_bytes(wth->fh, magic, MAGIC_SIZE, err, err_info)) {
		if (*err != WTAP_ERR_SHORT_READ)
			return WTAP_OPEN_ERROR;
		return WTAP_OPEN_NOT_MINE;
	}

	if (memcmp(magic, netmon_1_x_magic, MAGIC_SIZE) != 0 &&
	    memcmp(magic, netmon_2_x_magic, MAGIC_SIZE) != 0) {
		return WTAP_OPEN_NOT_MINE;
	}

	/* Read the rest of the header. */
	if (!wtap_read_bytes(wth->fh, &hdr, sizeof hdr, err, err_info))
		return WTAP_OPEN_ERROR;

	switch (hdr.ver_major) {

	case 1:
		file_type = netmon_1_x_file_type_subtype;
		break;

	case 2:
		file_type = netmon_2_x_file_type_subtype;
		break;

	default:
		*err = WTAP_ERR_UNSUPPORTED;
		*err_info = ws_strdup_printf("netmon: major version %u unsupported", hdr.ver_major);
		return WTAP_OPEN_ERROR;
	}

	hdr.network = pletoh16(&hdr.network);
	if (hdr.network >= NUM_NETMON_ENCAPS
	    || netmon_encap[hdr.network] == WTAP_ENCAP_UNKNOWN) {
		*err = WTAP_ERR_UNSUPPORTED;
		*err_info = ws_strdup_printf("netmon: network type %u unknown or unsupported",
		    hdr.network);
		return WTAP_OPEN_ERROR;
	}

	/* This is a netmon file */
	wth->file_type_subtype = file_type;
	netmon = g_new0(netmon_t, 1);
	wth->priv = (void *)netmon;
	wth->subtype_read = netmon_read;
	wth->subtype_seek_read = netmon_seek_read;
	wth->subtype_close = netmon_close;

	/* NetMon capture file formats v2.1+ use per-packet encapsulation types.  NetMon 3 sets the value in
	 * the header to 1 (Ethernet) for backwards compatibility. */
	if((hdr.ver_major == 2 && hdr.ver_minor >= 1) || hdr.ver_major > 2)
		wth->file_encap = WTAP_ENCAP_PER_PACKET;
	else
		wth->file_encap = netmon_encap[hdr.network];

	wth->snapshot_length = 0;	/* not available in header */
	/*
	 * Convert the time stamp to a "time_t" and a number of
	 * milliseconds.
	 */
	tm.tm_year = pletoh16(&hdr.ts_year) - 1900;
	tm.tm_mon = pletoh16(&hdr.ts_month) - 1;
	tm.tm_mday = pletoh16(&hdr.ts_day);
	tm.tm_hour = pletoh16(&hdr.ts_hour);
	tm.tm_min = pletoh16(&hdr.ts_min);
	tm.tm_sec = pletoh16(&hdr.ts_sec);
	tm.tm_isdst = -1;
	netmon->start_secs = mktime(&tm);
	/*
	 * XXX - what if "secs" is -1?  Unlikely, but if the capture was
	 * done in a time zone that switches between standard and summer
	 * time sometime other than when we do, and thus the time was one
	 * that doesn't exist here because a switch from standard to summer
	 * time zips over it, it could happen.
	 *
	 * On the other hand, if the capture was done in a different time
	 * zone, this won't work right anyway; unfortunately, the time
	 * zone isn't stored in the capture file (why the hell didn't
	 * they stuff a FILETIME, which is the number of 100-nanosecond
	 * intervals since 1601-01-01 00:00:00 "UTC", there, instead
	 * of stuffing a SYSTEMTIME, which is time-zone-dependent, there?).
	 *
	 * Eventually they went with per-packet FILETIMEs in a later
	 * version.
	 */
	netmon->start_nsecs = pletoh16(&hdr.ts_msec)*1000000;

	netmon->version_major = hdr.ver_major;
	netmon->version_minor = hdr.ver_minor;

	/*
	 * Get the offset of the frame index table.
	 */
	frame_table_offset = pletoh32(&hdr.frametableoffset);

	/*
	 * For NetMon 2.2 format and later, get the offset and length of
	 * the comment index table and process info table.
	 *
	 * For earlier versions, set them to zero; they appear to be
	 * uninitialized, so they're not necessarily zero.
	 */
	if ((netmon->version_major == 2 && netmon->version_minor >= 2) ||
	    netmon->version_major > 2) {
		comment_table_offset = pletoh32(&hdr.commentdataoffset);
		comment_table_size = pletoh32(&hdr.commentdatalength);
		process_info_table_offset = pletoh32(&hdr.processinfooffset);
		process_info_table_count = pletoh32(&hdr.processinfocount);
	} else {
		comment_table_offset = 0;
		comment_table_size = 0;
		process_info_table_offset = 0;
		process_info_table_count = 0;
	}

	/*
	 * It appears that some NetMon 2.x files don't have the
	 * first packet starting exactly 128 bytes into the file.
	 *
	 * Furthermore, it also appears that there are "holes" in
	 * the file, i.e. frame N+1 doesn't always follow immediately
	 * after frame N.
	 *
	 * Therefore, we must read the frame table, and use the offsets
	 * in it as the offsets of the frames.
	 */
	frame_table_length = pletoh32(&hdr.frametablelength);
	frame_table_size = frame_table_length / (guint32)sizeof (guint32);
	if ((frame_table_size * sizeof (guint32)) != frame_table_length) {
		*err = WTAP_ERR_BAD_FILE;
		*err_info = ws_strdup_printf("netmon: frame table length is %u, which is not a multiple of the size of an entry",
		    frame_table_length);
		return WTAP_OPEN_ERROR;
	}
	if (frame_table_size == 0) {
		*err = WTAP_ERR_BAD_FILE;
		*err_info = ws_strdup_printf("netmon: frame table length is %u, which means it's less than one entry in size",
		    frame_table_length);
		return WTAP_OPEN_ERROR;
	}
	/*
	 * XXX - clamp the size of the frame table, so that we don't
	 * attempt to allocate a huge frame table and fail.
	 *
	 * Given that file offsets in the frame table are 32-bit,
	 * a NetMon file cannot be bigger than 2^32 bytes.
	 * Given that a NetMon 1.x-format packet header is 8 bytes,
	 * that means a NetMon file cannot have more than
	 * 512*2^20 packets.  We'll pick that as the limit for
	 * now; it's 1/8th of a 32-bit address space, which is
	 * probably not going to exhaust the address space all by
	 * itself, and probably won't exhaust the backing store.
	 */
	if (frame_table_size > 512*1024*1024) {
		*err = WTAP_ERR_BAD_FILE;
		*err_info = ws_strdup_printf("netmon: frame table length is %u, which is larger than we support",
		    frame_table_length);
		return WTAP_OPEN_ERROR;
	}
	if (file_seek(wth->fh, frame_table_offset, SEEK_SET, err) == -1) {
		return WTAP_OPEN_ERROR;
	}

	/*
	 * Sanity check the comment table information before we bother to allocate
	 * large chunks of memory for the frame table
	 */
	if (comment_table_size > 0) {
		/*
		 * XXX - clamp the size of the comment table, so that we don't
		 * attempt to allocate a huge comment table and fail.
		 *
		 * Just use same size requires as frame table
		 */
		if (comment_table_size > 512*1024*1024) {
			*err = WTAP_ERR_BAD_FILE;
			*err_info = ws_strdup_printf("netmon: comment table size is %u, which is larger than we support",
				comment_table_size);
			return WTAP_OPEN_ERROR;
		}

		if (comment_table_size < 17) {
			*err = WTAP_ERR_BAD_FILE;
			*err_info = ws_strdup_printf("netmon: comment table size is %u, which is too small to use",
				comment_table_size);
			return WTAP_OPEN_ERROR;
		}

		if (comment_table_offset > file_size) {
			*err = WTAP_ERR_BAD_FILE;
			*err_info = ws_strdup_printf("netmon: comment table offset (%u) is larger than file",
				comment_table_offset);
			return WTAP_OPEN_ERROR;
		}
	}

	/*
	 * Sanity check the process info table information before we bother to allocate
	 * large chunks of memory for the frame table
	 */
	if ((process_info_table_offset > 0) && (process_info_table_count > 0)) {
		/*
		 * XXX - clamp the size of the process info table, so that we don't
		 * attempt to allocate a huge process info table and fail.
		 */
		if (process_info_table_count > 512*1024) {
			*err = WTAP_ERR_BAD_FILE;
			*err_info = ws_strdup_printf("netmon: process info table size is %u, which is larger than we support",
				process_info_table_count);
			return WTAP_OPEN_ERROR;
		}

		if (process_info_table_offset > file_size) {
			*err = WTAP_ERR_BAD_FILE;
			*err_info = ws_strdup_printf("netmon: process info table offset (%u) is larger than file",
				process_info_table_offset);
			return WTAP_OPEN_ERROR;
		}
	}

	/*
	 * Return back to the frame table offset
	 */
	if (file_seek(wth->fh, frame_table_offset, SEEK_SET, err) == -1) {
		return WTAP_OPEN_ERROR;
	}

	/*
	 * Sanity check the process info table information before we bother to allocate
	 * large chunks of memory for the frame table
	 */

	frame_table = (guint32 *)g_try_malloc(frame_table_length);
	if (frame_table_length != 0 && frame_table == NULL) {
		*err = ENOMEM;	/* we assume we're out of memory */
		return WTAP_OPEN_ERROR;
	}
	if (!wtap_read_bytes(wth->fh, frame_table, frame_table_length,
	    err, err_info)) {
		g_free(frame_table);
		return WTAP_OPEN_ERROR;
	}
	netmon->frame_table_size = frame_table_size;
	netmon->frame_table = frame_table;

	if (comment_table_size > 0) {
		comment_table = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL, netmonrec_comment_destroy);
		if (comment_table == NULL) {
			*err = ENOMEM;	/* we assume we're out of memory */
			return WTAP_OPEN_ERROR;
		}

		/* Make sure the file contains the full comment section */
		if (file_seek(wth->fh, comment_table_offset+comment_table_size, SEEK_SET, err) == -1) {
			g_hash_table_destroy(comment_table);
			return WTAP_OPEN_ERROR;
		}

		if (file_seek(wth->fh, comment_table_offset, SEEK_SET, err) == -1) {
			/* Shouldn't fail... */
			g_hash_table_destroy(comment_table);
			return WTAP_OPEN_ERROR;
		}

		while (comment_table_size > 16) {
			struct netmonrec_comment_header comment_header;
			guint32 title_length;
			guint32 desc_length;
			guint8 *utf16_str;

			/* Read the first 12 bytes of the structure */
			if (!wtap_read_bytes(wth->fh, &comment_header, 12, err, err_info)) {
				g_hash_table_destroy(comment_table);
				return WTAP_OPEN_ERROR;
			}
			comment_table_size -= 12;

			/* Make sure comment size is sane */
			title_length = pletoh32(&comment_header.titleLength);
			if (title_length == 0) {
				*err = WTAP_ERR_BAD_FILE;
				*err_info = g_strdup("netmon: comment title size can't be 0");
				g_hash_table_destroy(comment_table);
				return WTAP_OPEN_ERROR;
			}
			if (title_length > comment_table_size) {
				*err = WTAP_ERR_BAD_FILE;
				*err_info = ws_strdup_printf("netmon: comment title size is %u, which is larger than the amount remaining in the comment section (%u)",
						title_length, comment_table_size);
				g_hash_table_destroy(comment_table);
				return WTAP_OPEN_ERROR;
			}

			comment_rec = g_new0(struct netmonrec_comment, 1);
			comment_rec->numFramePerComment = pletoh32(&comment_header.numFramePerComment);
			comment_rec->frameOffset = pletoh32(&comment_header.frameOffset);

			g_hash_table_insert(comment_table, GUINT_TO_POINTER(comment_rec->frameOffset), comment_rec);

			/*
			 * Read in the comment title.
			 *
			 * It is in UTF-16-encoded Unicode, and the title
			 * size is a count of octets, not octet pairs or
			 * Unicode characters.
			 */
			utf16_str = (guint8*)g_malloc(title_length);
			if (!wtap_read_bytes(wth->fh, utf16_str, title_length,
			    err, err_info)) {
				g_hash_table_destroy(comment_table);
				return WTAP_OPEN_ERROR;
			}
			comment_table_size -= title_length;

			/*
			 * Now convert it to UTF-8 for internal use.
			 */
			comment_rec->title = utf_16_to_utf_8(utf16_str,
			    title_length);
			g_free(utf16_str);

			if (comment_table_size < 4) {
				*err = WTAP_ERR_BAD_FILE;
				*err_info = g_strdup("netmon: corrupt comment section");
				g_hash_table_destroy(comment_table);
				return WTAP_OPEN_ERROR;
			}

			if (!wtap_read_bytes(wth->fh, &desc_length, 4, err, err_info)) {
				g_hash_table_destroy(comment_table);
				return WTAP_OPEN_ERROR;
			}
			comment_table_size -= 4;

			comment_rec->descLength = pletoh32(&desc_length);
			if (comment_rec->descLength > 0) {
				/* Make sure comment size is sane */
				if (comment_rec->descLength > comment_table_size) {
					*err = WTAP_ERR_BAD_FILE;
					*err_info = ws_strdup_printf("netmon: comment description size is %u, which is larger than the amount remaining in the comment section (%u)",
								comment_rec->descLength, comment_table_size);
					g_hash_table_destroy(comment_table);
					return WTAP_OPEN_ERROR;
				}

				comment_rec->description = (guint8*)g_malloc(comment_rec->descLength);

				/* Read the comment description */
				if (!wtap_read_bytes(wth->fh, comment_rec->description, comment_rec->descLength, err, err_info)) {
					g_hash_table_destroy(comment_table);
					return WTAP_OPEN_ERROR;
				}

				comment_table_size -= comment_rec->descLength;
			}
		}
		netmon->comment_table = comment_table;
	}

	if ((process_info_table_offset > 0) && (process_info_table_count > 0)) {
		guint16 version;

		/* Go to the process table offset */
		if (file_seek(wth->fh, process_info_table_offset, SEEK_SET, err) == -1) {
			return WTAP_OPEN_ERROR;
		}

		process_info_table = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL, netmonrec_process_info_destroy);
		if (process_info_table == NULL) {
			*err = ENOMEM;	/* we assume we're out of memory */
			return WTAP_OPEN_ERROR;
		}

		/* Read the version (ignored for now) */
		if (!wtap_read_bytes(wth->fh, &version, 2, err, err_info)) {
			g_hash_table_destroy(process_info_table);
			return WTAP_OPEN_ERROR;
		}

		while (process_info_table_count > 0)
		{
			struct netmonrec_process_info* process_info;
			guint32 tmp32;
			guint16 tmp16;
			guint32 path_size;
			guint8 *utf16_str;

			process_info = g_new0(struct netmonrec_process_info, 1);

			/* Read path */
			if (!wtap_read_bytes(wth->fh, &tmp32, 4, err, err_info)) {
				g_free(process_info);
				g_hash_table_destroy(process_info_table);
				return WTAP_OPEN_ERROR;
			}

			path_size = pletoh32(&tmp32);
			if (path_size > MATH_PROCINFO_PATH_SIZE) {
				*err = WTAP_ERR_BAD_FILE;
				*err_info = ws_strdup_printf("netmon: Path size for process info record is %u, which is larger than allowed max value (%u)",
				    path_size, MATH_PROCINFO_PATH_SIZE);
				g_free(process_info);
				g_hash_table_destroy(process_info_table);
				return WTAP_OPEN_ERROR;
			}

			/*
			 * Read in the path string.
			 *
			 * It is in UTF-16-encoded Unicode, and the path
			 * size is a count of octets, not octet pairs or
			 * Unicode characters.
			 */
			utf16_str = (guint8*)g_malloc(path_size);
			if (!wtap_read_bytes(wth->fh, utf16_str, path_size,
			    err, err_info)) {
				g_free(process_info);
				g_hash_table_destroy(process_info_table);
				return WTAP_OPEN_ERROR;
			}

			/*
			 * Now convert it to UTF-8 for internal use.
			 */
			process_info->path = utf_16_to_utf_8(utf16_str,
			    path_size);
			g_free(utf16_str);

			/* Read icon (currently not saved) */
			if (!wtap_read_bytes(wth->fh, &tmp32, 4, err, err_info)) {
				g_free(process_info);
				g_hash_table_destroy(process_info_table);
				return WTAP_OPEN_ERROR;
			}

			process_info->iconSize = pletoh32(&tmp32);

			/* XXX - skip the icon for now */
			if (file_seek(wth->fh, process_info->iconSize, SEEK_CUR, err) == -1) {
				g_free(process_info);
				g_hash_table_destroy(process_info_table);
				return WTAP_OPEN_ERROR;
			}
			process_info->iconSize = 0;

			if (!wtap_read_bytes(wth->fh, &tmp32, 4, err, err_info)) {
				g_free(process_info);
				g_hash_table_destroy(process_info_table);
				return WTAP_OPEN_ERROR;
			}
			process_info->pid = pletoh32(&tmp32);

			/* XXX - Currently index process information by PID */
			g_hash_table_insert(process_info_table, GUINT_TO_POINTER(process_info->pid), process_info);

			/* Read local port */
			if (!wtap_read_bytes(wth->fh, &tmp16, 2, err, err_info)) {
				g_hash_table_destroy(process_info_table);
				return WTAP_OPEN_ERROR;
			}
			process_info->localPort = pletoh16(&tmp16);

			/* Skip padding */
			if (!wtap_read_bytes(wth->fh, &tmp16, 2, err, err_info)) {
				g_hash_table_destroy(process_info_table);
				return WTAP_OPEN_ERROR;
			}

			/* Read remote port */
			if (!wtap_read_bytes(wth->fh, &tmp16, 2, err, err_info)) {
				g_hash_table_destroy(process_info_table);
				return WTAP_OPEN_ERROR;
			}
			process_info->remotePort = pletoh16(&tmp16);

			/* Skip padding */
			if (!wtap_read_bytes(wth->fh, &tmp16, 2, err, err_info)) {
				g_hash_table_destroy(process_info_table);
				return WTAP_OPEN_ERROR;
			}

			/* Determine IP version */
			if (!wtap_read_bytes(wth->fh, &tmp32, 4, err, err_info)) {
				g_hash_table_destroy(process_info_table);
				return WTAP_OPEN_ERROR;
			}
			process_info->isIPv6 = ((pletoh32(&tmp32) == 0) ? FALSE : TRUE);

			if (process_info->isIPv6) {
				if (!wtap_read_bytes(wth->fh, &process_info->localAddr.ipv6, 16, err, err_info)) {
					g_hash_table_destroy(process_info_table);
					return WTAP_OPEN_ERROR;
				}
				if (!wtap_read_bytes(wth->fh, &process_info->remoteAddr.ipv6, 16, err, err_info)) {
					g_hash_table_destroy(process_info_table);
					return WTAP_OPEN_ERROR;
				}
			} else {
				guint8 ipbuffer[16];
				if (!wtap_read_bytes(wth->fh, ipbuffer, 16, err, err_info)) {
					g_hash_table_destroy(process_info_table);
					return WTAP_OPEN_ERROR;
				}
				process_info->localAddr.ipv4 = pletoh32(ipbuffer);

				if (!wtap_read_bytes(wth->fh, ipbuffer, 16, err, err_info)) {
					g_hash_table_destroy(process_info_table);
					return WTAP_OPEN_ERROR;
				}
				process_info->remoteAddr.ipv4 = pletoh32(ipbuffer);
			}

			process_info_table_count--;
		}

		netmon->process_info_table = process_info_table;
	}

#if G_BYTE_ORDER == G_BIG_ENDIAN
	/*
	 * OK, now byte-swap the frame table.
	 */
	for (i = 0; i < frame_table_size; i++)
		frame_table[i] = pletoh32(&frame_table[i]);
#endif

	/* Set up to start reading at the first frame. */
	netmon->current_frame = 0;
	switch (netmon->version_major) {

	case 1:
		/*
		 * Version 1.x of the file format supports
		 * millisecond precision.
		 */
		wth->file_tsprec = WTAP_TSPREC_MSEC;
		break;

	case 2:
		/*
		 * Versions 2.0 through 2.2 support microsecond
		 * precision; version 2.3 supports 100-nanosecond
		 * precision (2.3 was the last version).
		 */
		if (netmon->version_minor >= 3)
			wth->file_tsprec = WTAP_TSPREC_100_NSEC;
		else
			wth->file_tsprec = WTAP_TSPREC_USEC;
		break;
	}
	return WTAP_OPEN_MINE;
}

static void
netmon_set_pseudo_header_info(wtap_rec *rec, Buffer *buf)
{
	switch (rec->rec_header.packet_header.pkt_encap) {

	case WTAP_ENCAP_ATM_PDUS:
		/*
		 * Attempt to guess from the packet data, the VPI, and
		 * the VCI information about the type of traffic.
		 */
		atm_guess_traffic_type(rec, ws_buffer_start_ptr(buf));
		break;

	case WTAP_ENCAP_ETHERNET:
		/*
		 * We assume there's no FCS in this frame.
		 */
		rec->rec_header.packet_header.pseudo_header.eth.fcs_len = 0;
		break;

	case WTAP_ENCAP_IEEE_802_11_NETMON:
		/*
		 * The 802.11 metadata at the beginnning of the frame data
		 * is processed by a dissector, which fills in a pseudo-
		 * header and passes it to the 802.11 radio dissector,
		 * just as is done with other 802.11 radio metadata headers
		 * that are part of the packet data, such as radiotap.
		 */
		break;
	}
}

typedef enum {
	SUCCESS,
	FAILURE,
	RETRY
} process_record_retval;

static process_record_retval
netmon_process_record(wtap *wth, FILE_T fh, wtap_rec *rec,
    Buffer *buf, int *err, gchar **err_info)
{
	netmon_t *netmon = (netmon_t *)wth->priv;
	int	hdr_size = 0;
	union {
		struct netmonrec_1_x_hdr hdr_1_x;
		struct netmonrec_2_x_hdr hdr_2_x;
	}	hdr;
	gint64	delta = 0;	/* signed - frame times can be before the nominal start */
	gint64	t;
	time_t	secs;
	int	nsecs;
	guint32	packet_size = 0;
	guint32 orig_size = 0;
	int	trlr_size;
	union {
		struct netmonrec_2_1_trlr trlr_2_1;
		struct netmonrec_2_2_trlr trlr_2_2;
		struct netmonrec_2_3_trlr trlr_2_3;
	}	trlr;
	guint16 network;
	int	pkt_encap;
	struct netmonrec_comment* comment_rec = NULL;

	/* Read record header. */
	switch (netmon->version_major) {

	case 1:
		hdr_size = sizeof (struct netmonrec_1_x_hdr);
		break;

	case 2:
		hdr_size = sizeof (struct netmonrec_2_x_hdr);
		break;
	}
	if (!wtap_read_bytes_or_eof(fh, &hdr, hdr_size, err, err_info))
		return FAILURE;

	switch (netmon->version_major) {

	case 1:
		orig_size = pletoh16(&hdr.hdr_1_x.orig_len);
		packet_size = pletoh16(&hdr.hdr_1_x.incl_len);
		break;

	case 2:
		orig_size = pletoh32(&hdr.hdr_2_x.orig_len);
		packet_size = pletoh32(&hdr.hdr_2_x.incl_len);
		break;
	}
	if (packet_size > WTAP_MAX_PACKET_SIZE_STANDARD) {
		/*
		 * Probably a corrupt capture file; don't blow up trying
		 * to allocate space for an immensely-large packet.
		 */
		*err = WTAP_ERR_BAD_FILE;
		*err_info = ws_strdup_printf("netmon: File has %u-byte packet, bigger than maximum of %u",
		    packet_size, WTAP_MAX_PACKET_SIZE_STANDARD);
		return FAILURE;
	}

	rec->rec_type = REC_TYPE_PACKET;
	rec->block = wtap_block_create(WTAP_BLOCK_PACKET);

	/*
	 * If this is an ATM packet, the first
	 * "sizeof (struct netmon_atm_hdr)" bytes have destination and
	 * source addresses (6 bytes - MAC addresses of some sort?)
	 * and the VPI and VCI; read them and generate the pseudo-header
	 * from them.
	 */
	switch (wth->file_encap) {

	case WTAP_ENCAP_ATM_PDUS:
		if (packet_size < sizeof (struct netmon_atm_hdr)) {
			/*
			 * Uh-oh, the packet isn't big enough to even
			 * have a pseudo-header.
			 */
			*err = WTAP_ERR_BAD_FILE;
			*err_info = ws_strdup_printf("netmon: ATM file has a %u-byte packet, too small to have even an ATM pseudo-header",
			    packet_size);
			return FAILURE;
		}
		if (!netmon_read_atm_pseudoheader(fh, &rec->rec_header.packet_header.pseudo_header,
		    err, err_info))
			return FAILURE;	/* Read error */

		/*
		 * Don't count the pseudo-header as part of the packet.
		 */
		orig_size -= (guint)sizeof (struct netmon_atm_hdr);
		packet_size -= (guint)sizeof (struct netmon_atm_hdr);
		break;

	default:
		break;
	}

	switch (netmon->version_major) {

	case 1:
		/*
		 * According to Paul Long, this offset is unsigned.
		 * It's 32 bits, so the maximum value will fit in
		 * a gint64 such as delta, even after multiplying
		 * it by 1000000.
		 *
		 * pletoh32() returns a guint32; we cast it to gint64
		 * before multiplying, so that the product doesn't
		 * overflow a guint32.
		 */
		delta = ((gint64)pletoh32(&hdr.hdr_1_x.ts_delta))*1000000;
		break;

	case 2:
		/*
		 * OK, this is weird.  Microsoft's documentation
		 * says this is in microseconds and is a 64-bit
		 * unsigned number, but it can be negative; they
		 * say what appears to amount to "treat it as an
		 * unsigned number, multiply it by 10, and then
		 * interpret the resulting 64-bit quantity as a
		 * signed number".  That operation can turn a
		 * value with the uppermost bit 0 to a value with
		 * the uppermost bit 1, hence turning a large
		 * positive number-of-microseconds into a small
		 * negative number-of-100-nanosecond-increments.
		 */
		delta = pletoh64(&hdr.hdr_2_x.ts_delta)*10;

		/*
		 * OK, it's now a signed value in 100-nanosecond
		 * units.  Now convert it to nanosecond units.
		 */
		delta *= 100;
		break;
	}
	secs = 0;
	t = netmon->start_nsecs + delta;
	while (t < 0) {
		/*
		 * Propagate a borrow into the seconds.
		 * The seconds is a time_t, and can be < 0
		 * (unlikely, as Windows didn't exist before
		 * January 1, 1970, 00:00:00 UTC), while the
		 * nanoseconds should be positive, as in
		 * "nanoseconds since the instant of time
		 * represented by the seconds".
		 *
		 * We do not want t to be negative, as, according
		 * to the C90 standard, "if either operand [of /
		 * or %] is negative, whether the result of the
		 * / operator is the largest integer less than or
		 * equal to the algebraic quotient or the smallest
		 * greater than or equal to the algebraic quotient
		 * is implementation-defined, as is the sign of
		 * the result of the % operator", and we want
		 * the result of the division and remainder
		 * operations to be the same on all platforms.
		 */
		t += 1000000000;
		secs--;
	}
	secs += (time_t)(t/1000000000);
	nsecs = (int)(t%1000000000);
	rec->presence_flags = WTAP_HAS_TS|WTAP_HAS_CAP_LEN;
	rec->ts.secs = netmon->start_secs + secs;
	rec->ts.nsecs = nsecs;
	rec->rec_header.packet_header.caplen = packet_size;
	rec->rec_header.packet_header.len = orig_size;

	/*
	 * Read the packet data.
	 */
	if (!wtap_read_packet_bytes(fh, buf, rec->rec_header.packet_header.caplen, err, err_info))
		return FAILURE;

	/*
	 * For version 2.1 and later, there's additional information
	 * after the frame data.
	 */
	if (netmon->version_major == 2 && netmon->version_minor >= 1) {
		switch (netmon->version_minor) {

		case 1:
			trlr_size = (int)sizeof (struct netmonrec_2_1_trlr);
			break;

		case 2:
			trlr_size = (int)sizeof (struct netmonrec_2_2_trlr);
			break;

		default:
			trlr_size = (int)sizeof (struct netmonrec_2_3_trlr);
			break;
		}

		if (!wtap_read_bytes(fh, &trlr, trlr_size, err, err_info))
			return FAILURE;

		network = pletoh16(trlr.trlr_2_1.network);
		if ((network >= 0xE080) && (network <= 0xE08A)) {
			/* These values "violate" the LINKTYPE_ media type values
			 * in Microsoft Analyzer and are considered a MAExportedMediaType,
			 * so they need their own WTAP_ types
			 */
			switch (network)
			{
			case 0xE080:    // "WiFi Message"
				pkt_encap = WTAP_ENCAP_IEEE_802_11;
				break;
			case 0xE081:    // "Ndis Etw WiFi Channel Message"
			case 0xE082:    // "Fiddler Netmon Message"
			case 0xE089:    // "Pef Ndis Msg";
			case 0xE08A:    // "Pef Ndis Wifi Meta Msg";
				*err = WTAP_ERR_UNSUPPORTED;
				*err_info = ws_strdup_printf("netmon: network type %u unknown or unsupported", network);
				return FAILURE;
			case 0xE083:
				pkt_encap = WTAP_ENCAP_MA_WFP_CAPTURE_V4;
				break;
			case 0xE084:
				pkt_encap = WTAP_ENCAP_MA_WFP_CAPTURE_V6;
				break;
			case 0xE085:
				pkt_encap = WTAP_ENCAP_MA_WFP_CAPTURE_2V4;
				break;
			case 0xE086:
				pkt_encap = WTAP_ENCAP_MA_WFP_CAPTURE_2V6;
				break;
			case 0xE087:
				pkt_encap = WTAP_ENCAP_MA_WFP_CAPTURE_AUTH_V4;
				break;
			case 0xE088:
				pkt_encap = WTAP_ENCAP_MA_WFP_CAPTURE_AUTH_V6;
				break;
			default:
				pkt_encap = WTAP_ENCAP_UNKNOWN;
				break;
			}
		} else if ((network & 0xF000) == NETMON_NET_PCAP_BASE) {
			/*
			 * Converted pcap file - the LINKTYPE_ value
			 * is the network value with 0xF000 masked off.
			 */
			network &= 0x0FFF;
			pkt_encap = wtap_pcap_encap_to_wtap_encap(network);
			if (pkt_encap == WTAP_ENCAP_UNKNOWN) {
				*err = WTAP_ERR_UNSUPPORTED;
				*err_info = ws_strdup_printf("netmon: converted pcap network type %u unknown or unsupported",
				    network);
				return FAILURE;
			}
		} else if (network < NUM_NETMON_ENCAPS) {
			/*
			 * Regular NetMon encapsulation.
			 */
			pkt_encap = netmon_encap[network];
			if (pkt_encap == WTAP_ENCAP_UNKNOWN) {
				*err = WTAP_ERR_UNSUPPORTED;
				*err_info = ws_strdup_printf("netmon: network type %u unknown or unsupported",
				    network);
				return FAILURE;
			}
		} else {
			/*
			 * Special packet type for metadata.
			 */
			switch (network) {

			case NETMON_NET_NETEVENT:
				/*
				 * Event Tracing event.
				 *
				 * https://docs.microsoft.com/en-us/windows/win32/api/evntcons/ns-evntcons-event_header
				 */
				pkt_encap = WTAP_ENCAP_NETMON_NET_NETEVENT;
				break;

			case NETMON_NET_NETWORK_INFO_EX:
				/*
				 * List of adapters on which the capture
				 * was done.
				 * XXX - this could be translated into pcapng
				 * blocks but for now, just treat as a frame.
				 */
				pkt_encap = WTAP_ENCAP_NETMON_NETWORK_INFO_EX;
				break;

			case NETMON_NET_PAYLOAD_HEADER:
				/*
				 * Header for a fake frame constructed
				 * by reassembly.
				 */
				return RETRY;

			case NETMON_NET_NETWORK_INFO:
				/*
				 * List of adapters on which the capture
				 * was done.
				 */
				return RETRY;

			case NETMON_NET_DNS_CACHE:
				/*
				 * List of resolved IP addresses.
				 */
				return RETRY;

			case NETMON_NET_NETMON_FILTER:
				/*
				 * NetMon capture or display filter
				 * string.
				 */
				pkt_encap = WTAP_ENCAP_NETMON_NET_FILTER;
				break;

			default:
				*err = WTAP_ERR_UNSUPPORTED;
				*err_info = ws_strdup_printf("netmon: network type %u unknown or unsupported",
				    network);
				return FAILURE;
			}
		}

		rec->rec_header.packet_header.pkt_encap = pkt_encap;
		if (netmon->version_minor >= 3) {
			/*
			 * This is a 2.3 or later file.  That format
			 * contains a UTC per-packet time stamp; use
			 * that instead of the start time and offset.
			 */
			guint64 d;

			d = pletoh64(trlr.trlr_2_3.utc_timestamp);

			/*
			 * Get the time as seconds and nanoseconds.
			 * and overwrite the time stamp obtained
			 * from the record header.
			 */
			if (!filetime_to_nstime(&rec->ts, d)) {
				*err = WTAP_ERR_BAD_FILE;
				*err_info = g_strdup("netmon: time stamp outside supported range");
				return FAILURE;
			}
		}
	}

	netmon_set_pseudo_header_info(rec, buf);

	/* If any header specific information is present, set it as pseudo header data
	 * and set the encapsulation type, so it can be handled to the netmon_header
	 * dissector for further processing
	 */
	if (netmon->comment_table != NULL) {
		comment_rec = (struct netmonrec_comment*)g_hash_table_lookup(netmon->comment_table, GUINT_TO_POINTER(netmon->frame_table[netmon->current_frame-1]));
	}

	if (comment_rec != NULL) {
		union wtap_pseudo_header temp_header;

		/* These are the current encapsulation types that NetMon uses.
		 * Save them off so they can be copied to the NetMon pseudoheader
		 */
		switch (rec->rec_header.packet_header.pkt_encap)
		{
		case WTAP_ENCAP_ATM_PDUS:
			memcpy(&temp_header.atm, &rec->rec_header.packet_header.pseudo_header.atm, sizeof(temp_header.atm));
			break;
		case WTAP_ENCAP_ETHERNET:
			memcpy(&temp_header.eth, &rec->rec_header.packet_header.pseudo_header.eth, sizeof(temp_header.eth));
			break;
		case WTAP_ENCAP_IEEE_802_11_NETMON:
			memcpy(&temp_header.ieee_802_11, &rec->rec_header.packet_header.pseudo_header.ieee_802_11, sizeof(temp_header.ieee_802_11));
			break;
		}
		memset(&rec->rec_header.packet_header.pseudo_header.netmon, 0, sizeof(rec->rec_header.packet_header.pseudo_header.netmon));

		/* Save the current encapsulation type to the NetMon pseudoheader */
		rec->rec_header.packet_header.pseudo_header.netmon.sub_encap = rec->rec_header.packet_header.pkt_encap;

		/* Copy the comment data */
		rec->rec_header.packet_header.pseudo_header.netmon.title = comment_rec->title;
		rec->rec_header.packet_header.pseudo_header.netmon.descLength = comment_rec->descLength;
		rec->rec_header.packet_header.pseudo_header.netmon.description = comment_rec->description;

		/* Copy the saved pseudoheaders to the netmon pseudoheader structure */
		switch (rec->rec_header.packet_header.pkt_encap)
		{
		case WTAP_ENCAP_ATM_PDUS:
			memcpy(&rec->rec_header.packet_header.pseudo_header.netmon.subheader.atm, &temp_header.atm, sizeof(temp_header.atm));
			break;
		case WTAP_ENCAP_ETHERNET:
			memcpy(&rec->rec_header.packet_header.pseudo_header.netmon.subheader.eth, &temp_header.eth, sizeof(temp_header.eth));
			break;
		case WTAP_ENCAP_IEEE_802_11_NETMON:
			memcpy(&rec->rec_header.packet_header.pseudo_header.netmon.subheader.ieee_802_11, &temp_header.ieee_802_11, sizeof(temp_header.ieee_802_11));
			break;
		}

		/* Encapsulation type is now something that can be passed to netmon_header dissector */
		rec->rec_header.packet_header.pkt_encap = WTAP_ENCAP_NETMON_HEADER;
	}

	return SUCCESS;
}

/* Read the next packet */
static gboolean netmon_read(wtap *wth, wtap_rec *rec, Buffer *buf,
    int *err, gchar **err_info, gint64 *data_offset)
{
	netmon_t *netmon = (netmon_t *)wth->priv;
	gint64	rec_offset;

	for (;;) {
		/* Have we reached the end of the packet data? */
		if (netmon->current_frame >= netmon->frame_table_size) {
			*err = 0;	/* it's just an EOF, not an error */
			return FALSE;
		}

		/* Seek to the beginning of the current record, if we're
		   not there already (seeking to the current position
		   may still cause a seek and a read of the underlying file,
		   so we don't want to do it unconditionally).

		   Yes, the current record could be before the previous
		   record.  At least some captures put the trailer record
		   with statistics as the first physical record in the
		   file, but set the frame table up so it's the last
		   record in sequence. */
		rec_offset = netmon->frame_table[netmon->current_frame];
		if (file_tell(wth->fh) != rec_offset) {
			if (file_seek(wth->fh, rec_offset, SEEK_SET, err) == -1)
				return FALSE;
		}
		netmon->current_frame++;

		*data_offset = file_tell(wth->fh);

		switch (netmon_process_record(wth, wth->fh, rec, buf, err,
		    err_info)) {

		case RETRY:
			continue;

		case SUCCESS:
			return TRUE;

		case FAILURE:
			return FALSE;
		}
	}
}

static gboolean
netmon_seek_read(wtap *wth, gint64 seek_off,
    wtap_rec *rec, Buffer *buf, int *err, gchar **err_info)
{
	if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
		return FALSE;

	switch (netmon_process_record(wth, wth->random_fh, rec, buf, err,
	    err_info)) {

	default:
		/*
		 * This should not happen.
		 */
		*err = WTAP_ERR_BAD_FILE;
		*err_info = g_strdup("netmon: saw metadata in netmon_seek_read");
		return FALSE;

	case SUCCESS:
		return TRUE;

	case FAILURE:
		return FALSE;
	}
}

static gboolean
netmon_read_atm_pseudoheader(FILE_T fh, union wtap_pseudo_header *pseudo_header,
    int *err, gchar **err_info)
{
	struct netmon_atm_hdr atm_phdr;
	guint16	vpi, vci;

	if (!wtap_read_bytes(fh, &atm_phdr, sizeof (struct netmon_atm_hdr),
	    err, err_info))
		return FALSE;

	vpi = g_ntohs(atm_phdr.vpi);
	vci = g_ntohs(atm_phdr.vci);

	pseudo_header->atm.vpi = vpi;
	pseudo_header->atm.vci = vci;

	/* We don't have this information */
	pseudo_header->atm.flags = 0;
	pseudo_header->atm.channel = 0;
	pseudo_header->atm.cells = 0;
	pseudo_header->atm.aal5t_u2u = 0;
	pseudo_header->atm.aal5t_len = 0;
	pseudo_header->atm.aal5t_chksum = 0;

	return TRUE;
}

/* Throw away the frame table used by the sequential I/O stream. */
static void
netmon_close(wtap *wth)
{
	netmon_t *netmon = (netmon_t *)wth->priv;

	if (netmon->frame_table != NULL) {
		g_free(netmon->frame_table);
		netmon->frame_table = NULL;
	}

	if (netmon->comment_table != NULL) {
		g_hash_table_destroy(netmon->comment_table);
		netmon->comment_table = NULL;
	}

	if (netmon->process_info_table != NULL) {
		g_hash_table_destroy(netmon->process_info_table);
		netmon->process_info_table = NULL;
	}
}

typedef struct {
	gboolean is_v2;
	gboolean got_first_record_time;
	nstime_t first_record_time;
	guint32	frame_table_offset;
	guint32	*frame_table;
	guint	frame_table_index;
	guint	frame_table_size;
	gboolean no_more_room;		/* TRUE if no more records can be written */
} netmon_dump_t;

static const int wtap_encap[] = {
	-1,		/* WTAP_ENCAP_UNKNOWN -> unsupported */
	1,		/* WTAP_ENCAP_ETHERNET -> NDIS Ethernet */
	2,		/* WTAP_ENCAP_TOKEN_RING -> NDIS Token Ring */
	-1,		/* WTAP_ENCAP_SLIP -> unsupported */
	-1,		/* WTAP_ENCAP_PPP -> unsupported */
	3,		/* WTAP_ENCAP_FDDI -> NDIS FDDI */
	3,		/* WTAP_ENCAP_FDDI_BITSWAPPED -> NDIS FDDI */
	-1,		/* WTAP_ENCAP_RAW_IP -> unsupported */
	-1,		/* WTAP_ENCAP_ARCNET -> unsupported */
	-1,		/* WTAP_ENCAP_ARCNET_LINUX -> unsupported */
	-1,		/* WTAP_ENCAP_ATM_RFC1483 -> unsupported */
	-1,		/* WTAP_ENCAP_LINUX_ATM_CLIP -> unsupported */
	-1,		/* WTAP_ENCAP_LAPB -> unsupported*/
	4,		/* WTAP_ENCAP_ATM_PDUS -> NDIS WAN (*NOT* ATM!) */
};
#define NUM_WTAP_ENCAPS (sizeof wtap_encap / sizeof wtap_encap[0])

/* Returns 0 if we could write the specified encapsulation type,
   an error indication otherwise. */
static int netmon_dump_can_write_encap_1_x(int encap)
{
	/*
	 * Per-packet encapsulations are *not* supported in NetMon 1.x
	 * format.
	 */
	if (encap < 0 || (unsigned) encap >= NUM_WTAP_ENCAPS || wtap_encap[encap] == -1)
		return WTAP_ERR_UNWRITABLE_ENCAP;

	return 0;
}

static int netmon_dump_can_write_encap_2_x(int encap)
{
	/*
	 * Per-packet encapsulations are supported in NetMon 2.1
	 * format.
	 */
	if (encap == WTAP_ENCAP_PER_PACKET)
		return 0;

	if (encap < 0 || (unsigned) encap >= NUM_WTAP_ENCAPS || wtap_encap[encap] == -1)
		return WTAP_ERR_UNWRITABLE_ENCAP;

	return 0;
}

/* Returns TRUE on success, FALSE on failure; sets "*err" to an error code on
   failure */
static gboolean netmon_dump_open(wtap_dumper *wdh, gboolean is_v2,
                                 int *err, gchar **err_info _U_)
{
	netmon_dump_t *netmon;

	/* We can't fill in all the fields in the file header, as we
	   haven't yet written any packets.  As we'll have to rewrite
	   the header when we've written out all the packets, we just
	   skip over the header for now. */
	if (wtap_dump_file_seek(wdh, CAPTUREFILE_HEADER_SIZE, SEEK_SET, err) == -1)
		return FALSE;

	wdh->bytes_dumped = CAPTUREFILE_HEADER_SIZE;
	wdh->subtype_write = netmon_dump;
	wdh->subtype_finish = netmon_dump_finish;

	netmon = g_new(netmon_dump_t, 1);
	wdh->priv = (void *)netmon;
	netmon->is_v2 = is_v2;
	netmon->frame_table_offset = CAPTUREFILE_HEADER_SIZE;
	netmon->got_first_record_time = FALSE;
	netmon->frame_table = NULL;
	netmon->frame_table_index = 0;
	netmon->frame_table_size = 0;
	netmon->no_more_room = FALSE;

	return TRUE;
}

static gboolean netmon_dump_open_1_x(wtap_dumper *wdh, int *err, gchar **err_info _U_)
{
	return netmon_dump_open(wdh, FALSE, err, err_info);
}

static gboolean netmon_dump_open_2_x(wtap_dumper *wdh, int *err, gchar **err_info _U_)
{
	return netmon_dump_open(wdh, TRUE, err, err_info);
}

/* Write a record for a packet to a dump file.
   Returns TRUE on success, FALSE on failure. */
static gboolean netmon_dump(wtap_dumper *wdh, const wtap_rec *rec,
    const guint8 *pd, int *err, gchar **err_info _U_)
{
	const union wtap_pseudo_header *pseudo_header = &rec->rec_header.packet_header.pseudo_header;
	netmon_dump_t *netmon = (netmon_dump_t *)wdh->priv;
	struct netmonrec_1_x_hdr rec_1_x_hdr;
	struct netmonrec_2_x_hdr rec_2_x_hdr;
	void *hdrp;
	size_t rec_size;
	struct netmonrec_2_1_trlr rec_2_x_trlr;
	size_t hdr_size;
	struct netmon_atm_hdr atm_hdr;
	int atm_hdrsize;
	gint64	secs;
	gint32	nsecs;

	/* We can only write packet records. */
	if (rec->rec_type != REC_TYPE_PACKET) {
		*err = WTAP_ERR_UNWRITABLE_REC_TYPE;
		return FALSE;
	}

	if (netmon->is_v2) {
		/* Don't write anything we're not willing to read. */
		if (rec->rec_header.packet_header.caplen > WTAP_MAX_PACKET_SIZE_STANDARD) {
			*err = WTAP_ERR_PACKET_TOO_LARGE;
			return FALSE;
		}
	} else {
		/*
		 * Make sure this packet doesn't have a link-layer type that
		 * differs from the one for the file.
		 */
		if (wdh->file_encap != rec->rec_header.packet_header.pkt_encap) {
			*err = WTAP_ERR_ENCAP_PER_PACKET_UNSUPPORTED;
			return FALSE;
		}

		/*
		 * The length fields are 16-bit, so there's a hard limit
		 * of 65535.
		 */
		if (rec->rec_header.packet_header.caplen > 65535) {
			*err = WTAP_ERR_PACKET_TOO_LARGE;
			return FALSE;
		}
	}

	if (wdh->file_encap == WTAP_ENCAP_PER_PACKET) {
		/*
		 * Is this network type supported?
		 */
		if (rec->rec_header.packet_header.pkt_encap < 0 ||
		    (unsigned) rec->rec_header.packet_header.pkt_encap >= NUM_WTAP_ENCAPS ||
		    wtap_encap[rec->rec_header.packet_header.pkt_encap] == -1) {
			/*
			 * No.  Fail.
			 */
			*err = WTAP_ERR_UNWRITABLE_ENCAP;
			return FALSE;
		}

		/*
		 * Fill in the trailer with the network type.
		 */
		phtoles(rec_2_x_trlr.network, wtap_encap[rec->rec_header.packet_header.pkt_encap]);
	}

	/*
	 * Will the file offset of this frame fit in a 32-bit unsigned
	 * integer?
	 */
	if (netmon->no_more_room) {
		/*
		 * No, so the file is too big for NetMon format to
		 * handle.
		 */
		*err = EFBIG;
		return FALSE;
	}

	/*
	 * NetMon files have a capture start time in the file header,
	 * and have times relative to that in the packet headers;
	 * pick the time of the first packet as the capture start
	 * time.
	 *
	 * That time has millisecond resolution, so chop any
	 * sub-millisecond part of the time stamp off.
	 */
	if (!netmon->got_first_record_time) {
		netmon->first_record_time.secs = rec->ts.secs;
		netmon->first_record_time.nsecs =
		    (rec->ts.nsecs/1000000)*1000000;
		netmon->got_first_record_time = TRUE;
	}

	if (wdh->file_encap == WTAP_ENCAP_ATM_PDUS)
		atm_hdrsize = sizeof (struct netmon_atm_hdr);
	else
		atm_hdrsize = 0;
	secs = (gint64)(rec->ts.secs - netmon->first_record_time.secs);
	nsecs = rec->ts.nsecs - netmon->first_record_time.nsecs;
	while (nsecs < 0) {
		/*
		 * Propagate a borrow into the seconds.
		 * The seconds is a time_t, and can be < 0
		 * (unlikely, as neither UN*X nor DOS
		 * nor the original Mac System existed
		 * before January 1, 1970, 00:00:00 UTC),
		 * while the nanoseconds should be positive,
		 * as in "nanoseconds since the instant of time
		 * represented by the seconds".
		 *
		 * We do not want t to be negative, as, according
		 * to the C90 standard, "if either operand [of /
		 * or %] is negative, whether the result of the
		 * / operator is the largest integer less than or
		 * equal to the algebraic quotient or the smallest
		 * greater than or equal to the algebraic quotient
		 * is implementation-defined, as is the sign of
		 * the result of the % operator", and we want
		 * the result of the division and remainder
		 * operations to be the same on all platforms.
		 */
		nsecs += 1000000000;
		secs--;
	}
	if (netmon->is_v2) {
		rec_2_x_hdr.ts_delta = GUINT64_TO_LE(secs*1000000 + (nsecs + 500)/1000);
		rec_2_x_hdr.orig_len = GUINT32_TO_LE(rec->rec_header.packet_header.len + atm_hdrsize);
		rec_2_x_hdr.incl_len = GUINT32_TO_LE(rec->rec_header.packet_header.caplen + atm_hdrsize);
		hdrp = &rec_2_x_hdr;
		hdr_size = sizeof rec_2_x_hdr;
	} else {
		rec_1_x_hdr.ts_delta = GUINT32_TO_LE(secs*1000 + (nsecs + 500000)/1000000);
		rec_1_x_hdr.orig_len = GUINT16_TO_LE(rec->rec_header.packet_header.len + atm_hdrsize);
		rec_1_x_hdr.incl_len = GUINT16_TO_LE(rec->rec_header.packet_header.caplen + atm_hdrsize);
		hdrp = &rec_1_x_hdr;
		hdr_size = sizeof rec_1_x_hdr;
	}

	/*
	 * Keep track of the record size, as we need to update
	 * the current file offset.
	 */
	rec_size = 0;

	if (!wtap_dump_file_write(wdh, hdrp, hdr_size, err))
		return FALSE;
	rec_size += hdr_size;

	if (wdh->file_encap == WTAP_ENCAP_ATM_PDUS) {
		/*
		 * Write the ATM header.
		 * We supply all-zero destination and source addresses.
		 */
		memset(&atm_hdr.dest, 0, sizeof atm_hdr.dest);
		memset(&atm_hdr.src, 0, sizeof atm_hdr.src);
		atm_hdr.vpi = g_htons(pseudo_header->atm.vpi);
		atm_hdr.vci = g_htons(pseudo_header->atm.vci);
		if (!wtap_dump_file_write(wdh, &atm_hdr, sizeof atm_hdr, err))
			return FALSE;
		rec_size += sizeof atm_hdr;
	}

	if (!wtap_dump_file_write(wdh, pd, rec->rec_header.packet_header.caplen, err))
		return FALSE;
	rec_size += rec->rec_header.packet_header.caplen;

	if (wdh->file_encap == WTAP_ENCAP_PER_PACKET) {
		/*
		 * Write out the trailer.
		 */
		if (!wtap_dump_file_write(wdh, &rec_2_x_trlr,
		    sizeof rec_2_x_trlr, err))
			return FALSE;
		rec_size += sizeof rec_2_x_trlr;
	}

	/*
	 * Stash the file offset of this frame.
	 */
	if (netmon->frame_table_size == 0) {
		/*
		 * Haven't yet allocated the buffer for the frame table.
		 */
		netmon->frame_table = (guint32 *)g_malloc(1024 * sizeof *netmon->frame_table);
		netmon->frame_table_size = 1024;
	} else {
		/*
		 * We've allocated it; are we at the end?
		 */
		if (netmon->frame_table_index >= netmon->frame_table_size) {
			/*
			 * Yes - double the size of the frame table.
			 */
			netmon->frame_table_size *= 2;
			netmon->frame_table = (guint32 *)g_realloc(netmon->frame_table,
			    netmon->frame_table_size * sizeof *netmon->frame_table);
		}
	}

	netmon->frame_table[netmon->frame_table_index] =
	    GUINT32_TO_LE(netmon->frame_table_offset);

	/*
	 * Is this the last record we can write?
	 * I.e., will the frame table offset of the next record not fit
	 * in a 32-bit frame table offset entry?
	 *
	 * (We don't bother checking whether the number of frames
	 * will fit in a 32-bit value, as, even if each record were
	 * 1 byte, if there were more than 2^32-1 packets, the frame
	 * table offset of at least one of those packets will be >
	 * 2^32 - 1.)
	 *
	 * Note: this also catches the unlikely possibility that
	 * the record itself is > 2^32 - 1 bytes long.
	 */
	if ((guint64)netmon->frame_table_offset + rec_size > G_MAXUINT32) {
		/*
		 * Yup, too big.
		 */
		netmon->no_more_room = TRUE;
	}
	netmon->frame_table_index++;
	netmon->frame_table_offset += (guint32) rec_size;

	return TRUE;
}

/* Finish writing to a dump file.
   Returns TRUE on success, FALSE on failure. */
static gboolean netmon_dump_finish(wtap_dumper *wdh, int *err,
    gchar **err_info _U_)
{
	netmon_dump_t *netmon = (netmon_dump_t *)wdh->priv;
	size_t n_to_write;
	struct netmon_hdr file_hdr;
	const char *magicp;
	size_t magic_size;
	struct tm *tm;
	gint64 saved_bytes_dumped;

	/* Write out the frame table.  "netmon->frame_table_index" is
	   the number of entries we've put into it. */
	n_to_write = netmon->frame_table_index * sizeof *netmon->frame_table;
	if (!wtap_dump_file_write(wdh, netmon->frame_table, n_to_write, err))
		return FALSE;

	/* Now go fix up the file header. */
	if (wtap_dump_file_seek(wdh, 0, SEEK_SET, err) == -1)
		return FALSE;
	/* Save bytes_dumped since following calls to wtap_dump_file_write()
	 * will still (mistakenly) increase it.
	 */
	saved_bytes_dumped = wdh->bytes_dumped;
	memset(&file_hdr, '\0', sizeof file_hdr);
	if (netmon->is_v2) {
		magicp = netmon_2_x_magic;
		magic_size = sizeof netmon_2_x_magic;
		/*
		 * NetMon file version, for 2.x, is 2.0;
		 * for 3.0, it's 2.1.
		 *
		 * If the file encapsulation is WTAP_ENCAP_PER_PACKET,
		 * we need version 2.1.
		 *
		 * XXX - version 2.3 supports UTC time stamps; when
		 * should we use it?  According to the file format
		 * documentation, NetMon 3.3 "cannot properly
		 * interpret" the UTC timestamp information; does
		 * that mean it ignores it and uses the local-time
		 * start time and time deltas, or mishandles them?
		 * Also, NetMon 3.1 and earlier can't read version
		 * 2.2, much less version 2.3.
		 */
		file_hdr.ver_major = 2;
		file_hdr.ver_minor =
		    (wdh->file_encap == WTAP_ENCAP_PER_PACKET) ? 1 : 0;
	} else {
		magicp = netmon_1_x_magic;
		magic_size = sizeof netmon_1_x_magic;
		/* NetMon file version, for 1.x, is 1.1 */
		file_hdr.ver_major = 1;
		file_hdr.ver_minor = 1;
	}
	if (!wtap_dump_file_write(wdh, magicp, magic_size, err))
		return FALSE;

	if (wdh->file_encap == WTAP_ENCAP_PER_PACKET) {
		/*
		 * We're writing NetMon 2.1 format, so the media
		 * type in the file header is irrelevant.  Set it
		 * to 1, just as Network Monitor does.
		 */
		file_hdr.network = GUINT16_TO_LE(1);
	} else
		file_hdr.network = GUINT16_TO_LE(wtap_encap[wdh->file_encap]);
	tm = localtime(&netmon->first_record_time.secs);
	if (tm != NULL) {
		file_hdr.ts_year  = GUINT16_TO_LE(1900 + tm->tm_year);
		file_hdr.ts_month = GUINT16_TO_LE(tm->tm_mon + 1);
		file_hdr.ts_dow   = GUINT16_TO_LE(tm->tm_wday);
		file_hdr.ts_day   = GUINT16_TO_LE(tm->tm_mday);
		file_hdr.ts_hour  = GUINT16_TO_LE(tm->tm_hour);
		file_hdr.ts_min   = GUINT16_TO_LE(tm->tm_min);
		file_hdr.ts_sec   = GUINT16_TO_LE(tm->tm_sec);
	} else {
		file_hdr.ts_year  = GUINT16_TO_LE(1900 + 0);
		file_hdr.ts_month = GUINT16_TO_LE(0 + 1);
		file_hdr.ts_dow   = GUINT16_TO_LE(0);
		file_hdr.ts_day   = GUINT16_TO_LE(0);
		file_hdr.ts_hour  = GUINT16_TO_LE(0);
		file_hdr.ts_min   = GUINT16_TO_LE(0);
		file_hdr.ts_sec   = GUINT16_TO_LE(0);
	}
	file_hdr.ts_msec = GUINT16_TO_LE(netmon->first_record_time.nsecs/1000000);
	file_hdr.frametableoffset = GUINT32_TO_LE(netmon->frame_table_offset);
	file_hdr.frametablelength =
	    GUINT32_TO_LE(netmon->frame_table_index * sizeof *netmon->frame_table);
	if (!wtap_dump_file_write(wdh, &file_hdr, sizeof file_hdr, err))
		return FALSE;

	wdh->bytes_dumped = saved_bytes_dumped;
	return TRUE;
}

static const struct supported_block_type netmon_1_x_blocks_supported[] = {
	/*
	 * We support packet blocks, with no comments or other options.
	 */
	{ WTAP_BLOCK_PACKET, MULTIPLE_BLOCKS_SUPPORTED, NO_OPTIONS_SUPPORTED }
};

static const struct file_type_subtype_info netmon_1_x_info = {
	"Microsoft NetMon 1.x", "netmon1", "cap", NULL,
	TRUE, BLOCKS_SUPPORTED(netmon_1_x_blocks_supported),
	netmon_dump_can_write_encap_1_x, netmon_dump_open_1_x, NULL
};

static const struct supported_block_type netmon_2_x_blocks_supported[] = {
	/*
	 * We support packet blocks, with no comments or other options.
	 */
	{ WTAP_BLOCK_PACKET, MULTIPLE_BLOCKS_SUPPORTED, NO_OPTIONS_SUPPORTED }
};

static const struct file_type_subtype_info netmon_2_x_info = {
	"Microsoft NetMon 2.x", "netmon2", "cap", NULL,
	TRUE, BLOCKS_SUPPORTED(netmon_2_x_blocks_supported),
	netmon_dump_can_write_encap_2_x, netmon_dump_open_2_x, NULL
};

void register_netmon(void)
{
	netmon_1_x_file_type_subtype = wtap_register_file_type_subtype(&netmon_1_x_info);
	netmon_2_x_file_type_subtype = wtap_register_file_type_subtype(&netmon_2_x_info);

	/*
	 * Register names for backwards compatibility with the
	 * wtap_filetypes table in Lua.
	 */
	wtap_register_backwards_compatibility_lua_name("NETMON_1_x",
	    netmon_1_x_file_type_subtype);
	wtap_register_backwards_compatibility_lua_name("NETMON_2_x",
	    netmon_2_x_file_type_subtype);
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */