aboutsummaryrefslogtreecommitdiffstats
path: root/capture.c
blob: e59899b531ab47430c42fa6fbb1498a418831888 (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
/* capture.c
 * Routines for packet capture windows
 *
 * $Id$
 *
 * Ethereal - Network traffic analyzer
 * By Gerald Combs <gerald@ethereal.com>
 * Copyright 1998 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

/* With MSVC and a libethereal.dll this file needs to import some variables 
   in a special way. Therefore _NEED_VAR_IMPORT_ is defined. */
#define _NEED_VAR_IMPORT_

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#ifdef HAVE_LIBPCAP

#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif

#ifdef HAVE_SYS_WAIT_H
# include <sys/wait.h>
#endif

#ifndef _WIN32
/*
 * Define various POSIX macros (and, in the case of WCOREDUMP, non-POSIX
 * macros) on UNIX systems that don't have them.
 */
#ifndef WIFEXITED
# define WIFEXITED(status)	(((status) & 0177) == 0)
#endif
#ifndef WIFSTOPPED
# define WIFSTOPPED(status)	(((status) & 0177) == 0177)
#endif
#ifndef WIFSIGNALED
# define WIFSIGNALED(status)	(!WIFSTOPPED(status) && !WIFEXITED(status))
#endif
#ifndef WEXITSTATUS
# define WEXITSTATUS(status)	((status) >> 8)
#endif
#ifndef WTERMSIG
# define WTERMSIG(status)	((status) & 0177)
#endif
#ifndef WCOREDUMP
# define WCOREDUMP(status)	((status) & 0200)
#endif
#ifndef WSTOPSIG
# define WSTOPSIG(status)	((status) >> 8)
#endif
#endif /* _WIN32 */

#ifdef HAVE_IO_H
# include <io.h>
#endif

#include <pcap.h>

#include <glib.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <time.h>

#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif

#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif

#include <signal.h>
#include <errno.h>

#ifdef NEED_SNPRINTF_H
# include "snprintf.h"
#endif

/*
 * We don't want to do a "select()" on the pcap_t's file descriptor on
 * BSD (because "select()" doesn't work correctly on BPF devices on at
 * least some releases of some flavors of BSD), and we don't want to do
 * it on Windows (because "select()" is something for sockets, not for
 * arbitrary handles).  (Note that "Windows" here includes Cygwin;
 * even in its pretend-it's-UNIX environment, we're using WinPcap, not
 * a UNIX libpcap.)
 *
 * We *do* want to do it on other platforms, as, on other platforms (with
 * the possible exception of Ultrix and Digital UNIX), the read timeout
 * doesn't expire if no packets have arrived, so a "pcap_dispatch()" call
 * will block until packets arrive, causing the UI to hang.
 *
 * XXX - the various BSDs appear to define BSD in <sys/param.h>; we don't
 * want to include it if it's not present on this platform, however.
 */
#if !defined(__FreeBSD__) && !defined(__NetBSD__) && !defined(__OpenBSD__) && \
    !defined(__bsdi__) && !defined(__APPLE__) && !defined(_WIN32) && \
    !defined(__CYGWIN__)
# define MUST_DO_SELECT
#endif

#include <epan/packet.h>
#include <epan/dfilter/dfilter.h>
#include "file.h"
#include "capture.h"
#include "capture_sync.h"
#include "util.h"
#include "pcap-util.h"
#include "alert_box.h"
#include "simple_dialog.h"
#include <epan/prefs.h>
#include "globals.h"
#include "conditions.h"
#include "capture_stop_conditions.h"
#include "ringbuffer.h"

#include "wiretap/libpcap.h"
#include "wiretap/wtap.h"
#include "wiretap/wtap-capture.h"

#include <epan/dissectors/packet-ap1394.h>
#include <epan/dissectors/packet-atalk.h>
#include <epan/dissectors/packet-atm.h>
#include <epan/dissectors/packet-clip.h>
#include <epan/dissectors/packet-eth.h>
#include <epan/dissectors/packet-fddi.h>
#include <epan/dissectors/packet-null.h>
#include <epan/dissectors/packet-ppp.h>
#include <epan/dissectors/packet-raw.h>
#include <epan/dissectors/packet-sll.h>
#include <epan/dissectors/packet-tr.h>
#include <epan/dissectors/packet-ieee80211.h>
#include <epan/dissectors/packet-chdlc.h>
#include <epan/dissectors/packet-prism.h>
#include <epan/dissectors/packet-ipfc.h>
#include <epan/dissectors/packet-arcnet.h>

#ifdef _WIN32
#include "capture-wpcap.h"
#endif
#include "ui_util.h"

/*
 * Capture options.
 */
capture_options capture_opts;
gboolean quit_after_cap = FALSE;/* Makes a "capture only mode". Implies -k */
gboolean capture_child;	        /* if this is the child for "-S" */


typedef struct _loop_data {
  gboolean       go;           /* TRUE as long as we're supposed to keep capturing */
  gint           max;          /* Number of packets we're supposed to capture - 0 means infinite */
  int            err;          /* if non-zero, error seen while capturing */
  gint           linktype;
  gint           sync_packets;
  gboolean       pcap_err;     /* TRUE if error from pcap */
  gboolean       from_cap_pipe;/* TRUE if we are capturing data from a pipe */
  packet_counts  counts;
  wtap_dumper   *pdh;
#ifndef _WIN32
  gboolean       modified;     /* TRUE if data in the pipe uses modified pcap headers */
  gboolean       byte_swapped; /* TRUE if data in the pipe is byte swapped */
  unsigned int   bytes_to_read, bytes_read; /* Used by cap_pipe_dispatch */
  enum {
         STATE_EXPECT_REC_HDR, STATE_READ_REC_HDR,
         STATE_EXPECT_DATA,     STATE_READ_DATA
       } cap_pipe_state;

  enum { PIPOK, PIPEOF, PIPERR, PIPNEXIST } cap_pipe_err;
#endif
} loop_data;

/* Win32 needs the O_BINARY flag for open() */
#ifndef O_BINARY
#define O_BINARY	0
#endif

static gboolean normal_do_capture(gboolean is_tempfile);
static void capture_pcap_cb(guchar *, const struct pcap_pkthdr *,
  const guchar *);
static void get_capture_file_io_error(char *, int, const char *, int, gboolean);
static void popup_errmsg(const char *);
static void stop_capture_signal_handler(int signo);

#ifndef _WIN32
static void cap_pipe_adjust_header(loop_data *, struct pcap_hdr *, struct pcaprec_hdr *);
static int cap_pipe_open_live(char *, struct pcap_hdr *, loop_data *, char *, int);
static int cap_pipe_dispatch(int, loop_data *, struct pcap_hdr *, \
		struct pcaprec_modified_hdr *, guchar *, char *, int);
#endif






/* Open a specified file, or create a temporary file, and start a capture
   to the file in question.  Returns TRUE if the capture starts
   successfully, FALSE otherwise. */
gboolean
do_capture(const char *save_file)
{
  char tmpname[128+1];
  gboolean is_tempfile;
  gchar *capfile_name;
  gboolean ret;

  if (save_file != NULL) {
    /* If the Sync option is set, we return to the caller while the capture
     * is in progress.  Therefore we need to take a copy of save_file in
     * case the caller destroys it after we return.
     */
    capfile_name = g_strdup(save_file);
    if (capture_opts.multi_files_on) {
      /* ringbuffer is enabled */
      cfile.save_file_fd = ringbuf_init(capfile_name,
          (capture_opts.has_ring_num_files) ? capture_opts.ring_num_files : 0);
    } else {
      /* Try to open/create the specified file for use as a capture buffer. */
      cfile.save_file_fd = open(capfile_name, O_RDWR|O_BINARY|O_TRUNC|O_CREAT,
				0600);
    }
    is_tempfile = FALSE;
  } else {
    /* Choose a random name for the capture buffer */
    cfile.save_file_fd = create_tempfile(tmpname, sizeof tmpname, "ether");
    capfile_name = g_strdup(tmpname);
    is_tempfile = TRUE;
  }
  if (cfile.save_file_fd == -1) {
    if (is_tempfile) {
      simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
	"The temporary file to which the capture would be saved (\"%s\")"
	"could not be opened: %s.", capfile_name, strerror(errno));
    } else {
      if (capture_opts.multi_files_on) {
        ringbuf_error_cleanup();
      }
      open_failure_alert_box(capfile_name, errno, TRUE);
    }
    g_free(capfile_name);
    return FALSE;
  }
  cf_close(&cfile);
  g_assert(cfile.save_file == NULL);
  cfile.save_file = capfile_name;
  /* cfile.save_file is "g_free"ed below, which is equivalent to
     "g_free(capfile_name)". */

  if (capture_opts.sync_mode) {	
    /* sync mode: do the capture in a child process */
    ret = sync_pipe_do_capture(is_tempfile);
    /* capture is still running */
    set_main_window_name("(Live Capture in Progress) - Ethereal");
  } else {
    /* normal mode: do the capture synchronously */
    set_main_window_name("(Live Capture in Progress) - Ethereal");
    ret = normal_do_capture(is_tempfile);
    /* capture is finished here */
  }

  return ret;
}





/* start a normal capture session */
static gboolean
normal_do_capture(gboolean is_tempfile)
{
    int capture_succeeded;
    gboolean stats_known;
    struct pcap_stat stats;
    int err;

    /* Not sync mode. */
    capture_succeeded = capture(&stats_known, &stats);
    if (quit_after_cap) {
      /* DON'T unlink the save file.  Presumably someone wants it. */
        main_window_exit();
    }
    if (!capture_succeeded) {
      /* We didn't succeed in doing the capture, so we don't have a save
	 file. */
      if (capture_opts.multi_files_on) {
	ringbuf_free();
      } else {
	g_free(cfile.save_file);
      }
      cfile.save_file = NULL;
      return FALSE;
    }
    /* Capture succeeded; attempt to read in the capture file. */
    if ((err = cf_open(cfile.save_file, is_tempfile, &cfile)) != 0) {
      /* We're not doing a capture any more, so we don't have a save
	 file. */
      if (capture_opts.multi_files_on) {
	ringbuf_free();
      } else {
	g_free(cfile.save_file);
      }
      cfile.save_file = NULL;
      return FALSE;
    }

    /* Set the read filter to NULL. */
    cfile.rfcode = NULL;

    /* Get the packet-drop statistics.

       XXX - there are currently no packet-drop statistics stored
       in libpcap captures, and that's what we're reading.

       At some point, we will add support in Wiretap to return
       packet-drop statistics for capture file formats that store it,
       and will make "cf_read()" get those statistics from Wiretap.
       We clear the statistics (marking them as "not known") in
       "cf_open()", and "cf_read()" will only fetch them and mark
       them as known if Wiretap supplies them, so if we get the
       statistics now, after calling "cf_open()" but before calling
       "cf_read()", the values we store will be used by "cf_read()".

       If a future libpcap capture file format stores the statistics,
       we'll put them into the capture file that we write, and will
       thus not have to set them here - "cf_read()" will get them from
       the file and use them. */
    if (stats_known) {
      cfile.drops_known = TRUE;

      /* XXX - on some systems, libpcap doesn't bother filling in
         "ps_ifdrop" - it doesn't even set it to zero - so we don't
         bother looking at it.

         Ideally, libpcap would have an interface that gave us
         several statistics - perhaps including various interface
         error statistics - and would tell us which of them it
         supplies, allowing us to display only the ones it does. */
      cfile.drops = stats.ps_drop;
    }
    switch (cf_read(&cfile)) {

    case READ_SUCCESS:
    case READ_ERROR:
      /* Just because we got an error, that doesn't mean we were unable
         to read any of the file; we handle what we could get from the
         file. */
      break;

    case READ_ABORTED:
      /* Exit by leaving the main loop, so that any quit functions
         we registered get called. */
      main_window_nested_quit();
      return FALSE;
    }

    /* We're not doing a capture any more, so we don't have a save
       file. */
    if (capture_opts.multi_files_on) {
      ringbuf_free();
    } else {
      g_free(cfile.save_file);
    }
    cfile.save_file = NULL;

    /* if we didn't captured even a single packet, close the file again */
    if(cfile.count == 0) {
      simple_dialog(ESD_TYPE_INFO, ESD_BTN_OK, 
      "%sNo packets captured!%s\n\n"
      "As no data was captured, closing the %scapture file!",
      simple_dialog_primary_start(), simple_dialog_primary_end(),
      (cfile.is_tempfile) ? "temporary " : "");
      cf_close(&cfile);
    }
  return TRUE;
}

/*
 * Timeout, in milliseconds, for reads from the stream of captured packets.
 */
#define	CAP_READ_TIMEOUT	250

#ifndef _WIN32
/* Take care of byte order in the libpcap headers read from pipes.
 * (function taken from wiretap/libpcap.c) */
static void
cap_pipe_adjust_header(loop_data *ld, struct pcap_hdr *hdr, struct pcaprec_hdr *rechdr)
{
  if (ld->byte_swapped) {
    /* Byte-swap the record header fields. */
    rechdr->ts_sec = BSWAP32(rechdr->ts_sec);
    rechdr->ts_usec = BSWAP32(rechdr->ts_usec);
    rechdr->incl_len = BSWAP32(rechdr->incl_len);
    rechdr->orig_len = BSWAP32(rechdr->orig_len);
  }

  /* In file format version 2.3, the "incl_len" and "orig_len" fields were
     swapped, in order to match the BPF header layout.

     Unfortunately, some files were, according to a comment in the "libpcap"
     source, written with version 2.3 in their headers but without the
     interchanged fields, so if "incl_len" is greater than "orig_len" - which
     would make no sense - we assume that we need to swap them.  */
  if (hdr->version_major == 2 &&
      (hdr->version_minor < 3 ||
       (hdr->version_minor == 3 && rechdr->incl_len > rechdr->orig_len))) {
    guint32 temp;

    temp = rechdr->orig_len;
    rechdr->orig_len = rechdr->incl_len;
    rechdr->incl_len = temp;
  }
}

/* Mimic pcap_open_live() for pipe captures
 * We check if "pipename" is "-" (stdin) or a FIFO, open it, and read the
 * header.
 * N.B. : we can't read the libpcap formats used in RedHat 6.1 or SuSE 6.3
 * because we can't seek on pipes (see wiretap/libpcap.c for details) */
static int
cap_pipe_open_live(char *pipename, struct pcap_hdr *hdr, loop_data *ld,
                 char *errmsg, int errmsgl)
{
  struct stat pipe_stat;
  int         fd;
  guint32     magic;
  int         b, sel_ret;
  unsigned int bytes_read;
  fd_set      rfds;
  struct timeval timeout;

  /*
   * XXX Ethereal blocks until we return
   */
  if (strcmp(pipename, "-") == 0)
    fd = 0; /* read from stdin */
  else {
    if (stat(pipename, &pipe_stat) < 0) {
      if (errno == ENOENT || errno == ENOTDIR)
        ld->cap_pipe_err = PIPNEXIST;
      else {
        snprintf(errmsg, errmsgl,
          "The capture session could not be initiated "
          "due to error on pipe: %s", strerror(errno));
        ld->cap_pipe_err = PIPERR;
      }
      return -1;
    }
    if (! S_ISFIFO(pipe_stat.st_mode)) {
      if (S_ISCHR(pipe_stat.st_mode)) {
        /*
         * Assume the user specified an interface on a system where
         * interfaces are in /dev.  Pretend we haven't seen it.
         */
         ld->cap_pipe_err = PIPNEXIST;
      } else {
        snprintf(errmsg, errmsgl,
            "The capture session could not be initiated because\n"
            "\"%s\" is neither an interface nor a pipe", pipename);
        ld->cap_pipe_err = PIPERR;
      }
      return -1;
    }
    fd = open(pipename, O_RDONLY | O_NONBLOCK);
    if (fd == -1) {
      snprintf(errmsg, errmsgl,
          "The capture session could not be initiated "
          "due to error on pipe open: %s", strerror(errno));
      ld->cap_pipe_err = PIPERR;
      return -1;
    }
  }

  ld->from_cap_pipe = TRUE;

  /* read the pcap header */
  FD_ZERO(&rfds);
  bytes_read = 0;
  while (bytes_read < sizeof magic) {
    FD_SET(fd, &rfds);
    timeout.tv_sec = 0;
    timeout.tv_usec = CAP_READ_TIMEOUT*1000;
    sel_ret = select(fd+1, &rfds, NULL, NULL, &timeout);
    if (sel_ret < 0) {
      snprintf(errmsg, errmsgl,
        "Unexpected error from select: %s", strerror(errno));
      goto error;
    } else if (sel_ret > 0) {
      b = read(fd, ((char *)&magic)+bytes_read, sizeof magic-bytes_read);
      if (b <= 0) {
        if (b == 0)
          snprintf(errmsg, errmsgl, "End of file on pipe during open");
        else
          snprintf(errmsg, errmsgl, "Error on pipe during open: %s",
            strerror(errno));
        goto error;
      }
      bytes_read += b;
    }
  }

  switch (magic) {
  case PCAP_MAGIC:
    /* Host that wrote it has our byte order, and was running
       a program using either standard or ss990417 libpcap. */
    ld->byte_swapped = FALSE;
    ld->modified = FALSE;
    break;
  case PCAP_MODIFIED_MAGIC:
    /* Host that wrote it has our byte order, but was running
       a program using either ss990915 or ss991029 libpcap. */
    ld->byte_swapped = FALSE;
    ld->modified = TRUE;
    break;
  case PCAP_SWAPPED_MAGIC:
    /* Host that wrote it has a byte order opposite to ours,
       and was running a program using either standard or
       ss990417 libpcap. */
    ld->byte_swapped = TRUE;
    ld->modified = FALSE;
    break;
  case PCAP_SWAPPED_MODIFIED_MAGIC:
    /* Host that wrote it out has a byte order opposite to
       ours, and was running a program using either ss990915
       or ss991029 libpcap. */
    ld->byte_swapped = TRUE;
    ld->modified = TRUE;
    break;
  default:
    /* Not a "libpcap" type we know about. */
    snprintf(errmsg, errmsgl, "Unrecognized libpcap format");
    goto error;
  }

  /* Read the rest of the header */
  bytes_read = 0;
  while (bytes_read < sizeof(struct pcap_hdr)) {
    FD_SET(fd, &rfds);
    timeout.tv_sec = 0;
    timeout.tv_usec = CAP_READ_TIMEOUT*1000;
    sel_ret = select(fd+1, &rfds, NULL, NULL, &timeout);
    if (sel_ret < 0) {
      snprintf(errmsg, errmsgl,
        "Unexpected error from select: %s", strerror(errno));
      goto error;
    } else if (sel_ret > 0) {
      b = read(fd, ((char *)hdr)+bytes_read,
            sizeof(struct pcap_hdr) - bytes_read);
      if (b <= 0) {
        if (b == 0)
          snprintf(errmsg, errmsgl, "End of file on pipe during open");
        else
          snprintf(errmsg, errmsgl, "Error on pipe during open: %s",
            strerror(errno));
        goto error;
      }
      bytes_read += b;
    }
  }

  if (ld->byte_swapped) {
    /* Byte-swap the header fields about which we care. */
    hdr->version_major = BSWAP16(hdr->version_major);
    hdr->version_minor = BSWAP16(hdr->version_minor);
    hdr->snaplen = BSWAP32(hdr->snaplen);
    hdr->network = BSWAP32(hdr->network);
  }

  if (hdr->version_major < 2) {
    snprintf(errmsg, errmsgl, "Unable to read old libpcap format");
    goto error;
  }

  ld->cap_pipe_state = STATE_EXPECT_REC_HDR;
  ld->cap_pipe_err = PIPOK;
  return fd;

error:
  ld->cap_pipe_err = PIPERR;
  close(fd);
  return -1;

}

/* We read one record from the pipe, take care of byte order in the record
 * header, write the record in the capture file, and update capture statistics. */

static int
cap_pipe_dispatch(int fd, loop_data *ld, struct pcap_hdr *hdr,
		struct pcaprec_modified_hdr *rechdr, guchar *data,
		char *errmsg, int errmsgl)
{
  struct pcap_pkthdr phdr;
  int b;
  enum { PD_REC_HDR_READ, PD_DATA_READ, PD_PIPE_EOF, PD_PIPE_ERR,
          PD_ERR } result;

  switch (ld->cap_pipe_state) {

  case STATE_EXPECT_REC_HDR:
    ld->bytes_to_read = ld->modified ?
      sizeof(struct pcaprec_modified_hdr) : sizeof(struct pcaprec_hdr);
    ld->bytes_read = 0;
    ld->cap_pipe_state = STATE_READ_REC_HDR;
    /* Fall through */

  case STATE_READ_REC_HDR:
    b = read(fd, ((char *)rechdr)+ld->bytes_read,
      ld->bytes_to_read - ld->bytes_read);
    if (b <= 0) {
      if (b == 0)
        result = PD_PIPE_EOF;
      else
        result = PD_PIPE_ERR;
      break;
    }
    if ((ld->bytes_read += b) < ld->bytes_to_read)
        return 0;
    result = PD_REC_HDR_READ;
    break;

  case STATE_EXPECT_DATA:
    ld->bytes_read = 0;
    ld->cap_pipe_state = STATE_READ_DATA;
    /* Fall through */

  case STATE_READ_DATA:
    b = read(fd, data+ld->bytes_read, rechdr->hdr.incl_len - ld->bytes_read);
    if (b <= 0) {
      if (b == 0)
        result = PD_PIPE_EOF;
      else
        result = PD_PIPE_ERR;
      break;
    }
    if ((ld->bytes_read += b) < rechdr->hdr.incl_len)
      return 0;
    result = PD_DATA_READ;
    break;

  default:
    snprintf(errmsg, errmsgl, "cap_pipe_dispatch: invalid state");
    result = PD_ERR;

  } /* switch (ld->cap_pipe_state) */

  /*
   * We've now read as much data as we were expecting, so process it.
   */
  switch (result) {

  case PD_REC_HDR_READ:
    /* We've read the header. Take care of byte order. */
    cap_pipe_adjust_header(ld, hdr, &rechdr->hdr);
    if (rechdr->hdr.incl_len > WTAP_MAX_PACKET_SIZE) {
      snprintf(errmsg, errmsgl, "Frame %u too long (%d bytes)",
        ld->counts.total+1, rechdr->hdr.incl_len);
      break;
    }
    ld->cap_pipe_state = STATE_EXPECT_DATA;
    return 0;

  case PD_DATA_READ:
    /* Fill in a "struct pcap_pkthdr", and process the packet. */
    phdr.ts.tv_sec = rechdr->hdr.ts_sec;
    phdr.ts.tv_usec = rechdr->hdr.ts_usec;
    phdr.caplen = rechdr->hdr.incl_len;
    phdr.len = rechdr->hdr.orig_len;

    capture_pcap_cb((guchar *)ld, &phdr, data);

    ld->cap_pipe_state = STATE_EXPECT_REC_HDR;
    return 1;

  case PD_PIPE_EOF:
    ld->cap_pipe_err = PIPEOF;
    return -1;

  case PD_PIPE_ERR:
    snprintf(errmsg, errmsgl, "Error reading from pipe: %s",
      strerror(errno));
    /* Fall through */
  case PD_ERR:
    break;
  }

  ld->cap_pipe_err = PIPERR;
  /* Return here rather than inside the switch to prevent GCC warning */
  return -1;
}
#endif /* not _WIN32 */

/*
 * This needs to be static, so that the SIGUSR1 handler can clear the "go"
 * flag.
 */
static loop_data   ld;

/* Do the low-level work of a capture.
   Returns TRUE if it succeeds, FALSE otherwise. */
int
capture(gboolean *stats_known, struct pcap_stat *stats)
{
  pcap_t     *pch;
  int         pcap_encap;
  int         file_snaplen;
  gchar       open_err_str[PCAP_ERRBUF_SIZE];
  gchar       lookup_net_err_str[PCAP_ERRBUF_SIZE];
  bpf_u_int32 netnum, netmask;
  struct bpf_program fcode;
  const char *set_linktype_err_str;
  time_t      upd_time, cur_time;
  time_t      start_time;
  int         err, inpkts;
  condition  *cnd_file_duration = NULL;
  condition  *cnd_autostop_files = NULL;
  condition  *cnd_autostop_size = NULL;
  condition  *cnd_autostop_duration = NULL;
  guint32     autostop_files = 0;
  char        errmsg[4096+1];
  gboolean    write_ok;
  gboolean    close_ok;
  capture_info   capture_ui;

#ifdef _WIN32
  WORD        wVersionRequested;
  WSADATA     wsaData;
#else
  fd_set      set1;
  struct timeval timeout;
  static const char ppamsg[] = "can't find PPA for ";
  char       *libpcap_warn;
  int         sel_ret;
  int         pipe_fd = -1;
  struct pcap_hdr hdr;
  struct pcaprec_modified_hdr rechdr;
  guchar pcap_data[WTAP_MAX_PACKET_SIZE];
#endif
#ifdef MUST_DO_SELECT
  int         pcap_fd = 0;
#endif
  gboolean    show_info = capture_opts.show_info || !capture_opts.sync_mode;

  /* Initialize Windows Socket if we are in a WIN32 OS
     This needs to be done before querying the interface for network/netmask */
#ifdef _WIN32
  /* XXX - do we really require 1.1 or earlier?
     Are there any versions that support only 2.0 or higher? */
  wVersionRequested = MAKEWORD(1, 1);
  err = WSAStartup(wVersionRequested, &wsaData);
  if (err != 0) {
    switch (err) {

    case WSASYSNOTREADY:
      snprintf(errmsg, sizeof errmsg,
        "Couldn't initialize Windows Sockets: Network system not ready for network communication");
      break;

    case WSAVERNOTSUPPORTED:
      snprintf(errmsg, sizeof errmsg,
        "Couldn't initialize Windows Sockets: Windows Sockets version %u.%u not supported",
        LOBYTE(wVersionRequested), HIBYTE(wVersionRequested));
      break;

    case WSAEINPROGRESS:
      snprintf(errmsg, sizeof errmsg,
        "Couldn't initialize Windows Sockets: Blocking operation is in progress");
      break;

    case WSAEPROCLIM:
      snprintf(errmsg, sizeof errmsg,
        "Couldn't initialize Windows Sockets: Limit on the number of tasks supported by this WinSock implementation has been reached");
      break;

    case WSAEFAULT:
      snprintf(errmsg, sizeof errmsg,
        "Couldn't initialize Windows Sockets: Bad pointer passed to WSAStartup");
      break;

    default:
      snprintf(errmsg, sizeof errmsg,
        "Couldn't initialize Windows Sockets: error %d", err);
      break;
    }
    pch = NULL;
    goto error;
  }
#endif

  ld.go             = TRUE;
  ld.counts.total   = 0;
  if (capture_opts.has_autostop_packets)
    ld.max          = capture_opts.autostop_packets;
  else
    ld.max          = 0;	/* no limit */
  ld.err            = 0;	/* no error seen yet */
  ld.linktype       = WTAP_ENCAP_UNKNOWN;
  ld.pcap_err       = FALSE;
  ld.from_cap_pipe  = FALSE;
  ld.sync_packets   = 0;
  ld.counts.sctp    = 0;
  ld.counts.tcp     = 0;
  ld.counts.udp     = 0;
  ld.counts.icmp    = 0;
  ld.counts.ospf    = 0;
  ld.counts.gre     = 0;
  ld.counts.ipx     = 0;
  ld.counts.netbios = 0;
  ld.counts.vines   = 0;
  ld.counts.other   = 0;
  ld.counts.arp     = 0;
  ld.pdh            = NULL;

  /* We haven't yet gotten the capture statistics. */
  *stats_known      = FALSE;

  /* Open the network interface to capture from it.
     Some versions of libpcap may put warnings into the error buffer
     if they succeed; to tell if that's happened, we have to clear
     the error buffer, and check if it's still a null string.  */
  open_err_str[0] = '\0';
  pch = pcap_open_live(cfile.iface,
		       capture_opts.has_snaplen ? capture_opts.snaplen :
						  WTAP_MAX_PACKET_SIZE,
		       capture_opts.promisc_mode, CAP_READ_TIMEOUT,
		       open_err_str);

  if (pch != NULL) {
#ifdef _WIN32
    /* try to set the capture buffer size */
    if (pcap_setbuff(pch, capture_opts.buffer_size * 1024 * 1024) != 0) {
        simple_dialog(ESD_TYPE_INFO, ESD_BTN_OK,
          "%sCouldn't set the capture buffer size!%s\n"
          "\n"
          "The capture buffer size of %luMB seems to be too high for your machine,\n"
          "the default of 1MB will be used.\n"
          "\n"
          "Nonetheless, the capture is started.\n",
          simple_dialog_primary_start(), simple_dialog_primary_end(), capture_opts.buffer_size);
    }
#endif

    /* setting the data link type only works on real interfaces */
    if (capture_opts.linktype != -1) {
      set_linktype_err_str = set_pcap_linktype(pch, cfile.iface,
	capture_opts.linktype);
      if (set_linktype_err_str != NULL) {
	snprintf(errmsg, sizeof errmsg, "Unable to set data link type (%s).",
	  set_linktype_err_str);
	goto error;
      }
    }
  } else {
    /* We couldn't open "cfile.iface" as a network device. */
#ifdef _WIN32
    /* On Windows, we don't support capturing on pipes, so we give up.
       If this is a child process that does the capturing in sync
       mode or fork mode, it shouldn't do any UI stuff until we pop up the
       capture-progress window, and, since we couldn't start the
       capture, we haven't popped it up. */
    if (!capture_child) {
      main_window_update();
    }

    /* On Win32 OSes, the capture devices are probably available to all
       users; don't warn about permissions problems.

       Do, however, warn that WAN devices aren't supported. */
    snprintf(errmsg, sizeof errmsg,
	"The capture session could not be initiated (%s).\n"
	"Please check that you have the proper interface specified.\n"
	"\n"
	"Note that the WinPcap 2.x version of the driver Ethereal uses for packet\n"
	"capture on Windows doesn't support capturing on PPP/WAN interfaces in\n"
	"Windows NT/2000/XP/2003 Server, and that the WinPcap 3.0 and later versions\n"
	"don't support capturing on PPP/WAN interfaces at all.",
	open_err_str);
    goto error;
#else
    /* try to open cfile.iface as a pipe */
    pipe_fd = cap_pipe_open_live(cfile.iface, &hdr, &ld, errmsg, sizeof errmsg);

    if (pipe_fd == -1) {

      /* If this is a child process that does the capturing in sync
       * mode or fork mode, it shouldn't do any UI stuff until we pop up the
       * capture-progress window, and, since we couldn't start the
       * capture, we haven't popped it up.
       */
      if (!capture_child) {
          main_window_update();
      }

      if (ld.cap_pipe_err == PIPNEXIST) {
	/* Pipe doesn't exist, so output message for interface */

	/* If we got a "can't find PPA for XXX" message, warn the user (who
	   is running Ethereal on HP-UX) that they don't have a version
	   of libpcap that properly handles HP-UX (libpcap 0.6.x and later
	   versions, which properly handle HP-UX, say "can't find /dev/dlpi
	   PPA for XXX" rather than "can't find PPA for XXX"). */
	if (strncmp(open_err_str, ppamsg, sizeof ppamsg - 1) == 0)
	  libpcap_warn =
	    "\n\n"
	    "You are running Ethereal with a version of the libpcap library\n"
	    "that doesn't handle HP-UX network devices well; this means that\n"
	    "Ethereal may not be able to capture packets.\n"
	    "\n"
	    "To fix this, you should install libpcap 0.6.2, or a later version\n"
	    "of libpcap, rather than libpcap 0.4 or 0.5.x.  It is available in\n"
	    "packaged binary form from the Software Porting And Archive Centre\n"
	    "for HP-UX; the Centre is at http://hpux.connect.org.uk/ - the page\n"
	    "at the URL lists a number of mirror sites.";
	else
	  libpcap_warn = "";
	snprintf(errmsg, sizeof errmsg,
	  "The capture session could not be initiated (%s).\n"
	  "Please check to make sure you have sufficient permissions, and that\n"
	  "you have the proper interface or pipe specified.%s", open_err_str,
	  libpcap_warn);
      }
      /*
       * Else pipe (or file) does exist and cap_pipe_open_live() has
       * filled in errmsg
       */
      goto error;
    } else
      /* cap_pipe_open_live() succeeded; don't want
         error message from pcap_open_live() */
      open_err_str[0] = '\0';
#endif
  }

  /* capture filters only work on real interfaces */
  if (cfile.cfilter && !ld.from_cap_pipe) {
    /* A capture filter was specified; set it up. */
    if (pcap_lookupnet(cfile.iface, &netnum, &netmask, lookup_net_err_str) < 0) {
      /*
       * Well, we can't get the netmask for this interface; it's used
       * only for filters that check for broadcast IP addresses, so
       * we just punt and use 0.  It might be nice to warn the user,
       * but that's a pain in a GUI application, as it'd involve popping
       * up a message box, and it's not clear how often this would make
       * a difference (only filters that check for IP broadcast addresses
       * use the netmask).
       */
      netmask = 0;
    }
    if (pcap_compile(pch, &fcode, cfile.cfilter, 1, netmask) < 0) {
      dfilter_t   *rfcode = NULL;
      /* filter string invalid, did the user tried a display filter? */
      if (dfilter_compile(cfile.cfilter, &rfcode) && rfcode != NULL) {
        snprintf(errmsg, sizeof errmsg,
          "%sInvalid capture filter: \"%s\"!%s\n"
          "\n"
          "That string looks like a valid display filter; however, it is not a valid\n"
          "capture filter (%s).\n"
          "\n"
          "Note that display filters and capture filters don't have the same syntax,\n"
          "so you can't use most display filter expressions as capture filters.\n"
          "\n"
          "See the help for a description of the capture filter syntax.",
          simple_dialog_primary_start(), cfile.cfilter, simple_dialog_primary_end(),
          pcap_geterr(pch));
	dfilter_free(rfcode);
      } else {
        snprintf(errmsg, sizeof errmsg,
          "%sInvalid capture filter: \"%s\"!%s\n"
          "\n"
          "That string is not a valid capture filter (%s).\n"
          "See the help for a description of the capture filter syntax.",
          simple_dialog_primary_start(), cfile.cfilter, simple_dialog_primary_end(),
          pcap_geterr(pch));
      }
      goto error;
    }
    if (pcap_setfilter(pch, &fcode) < 0) {
      snprintf(errmsg, sizeof errmsg, "Can't install filter (%s).",
	pcap_geterr(pch));
      goto error;
    }
  }

  /* Set up to write to the capture file. */
#ifndef _WIN32
  if (ld.from_cap_pipe) {
    pcap_encap = hdr.network;
    file_snaplen = hdr.snaplen;
  } else
#endif
  {
    pcap_encap = get_pcap_linktype(pch, cfile.iface);
    file_snaplen = pcap_snapshot(pch);
  }
  ld.linktype = wtap_pcap_encap_to_wtap_encap(pcap_encap);
  if (ld.linktype == WTAP_ENCAP_UNKNOWN) {
    snprintf(errmsg, sizeof errmsg,
	"The network you're capturing from is of a type"
	" that Ethereal doesn't support (data link type %d).", pcap_encap);
    goto error;
  }
  if (capture_opts.multi_files_on) {
    ld.pdh = ringbuf_init_wtap_dump_fdopen(WTAP_FILE_PCAP, ld.linktype,
      file_snaplen, &err);
  } else {
    ld.pdh = wtap_dump_fdopen(cfile.save_file_fd, WTAP_FILE_PCAP,
      ld.linktype, file_snaplen, &err);
  }

  if (ld.pdh == NULL) {
    /* We couldn't set up to write to the capture file. */
    switch (err) {

    case WTAP_ERR_CANT_OPEN:
      strcpy(errmsg, "The file to which the capture would be saved"
               " couldn't be created for some unknown reason.");
      break;

    case WTAP_ERR_SHORT_WRITE:
      strcpy(errmsg, "A full header couldn't be written to the file"
               " to which the capture would be saved.");
      break;

    default:
      if (err < 0) {
        snprintf(errmsg, sizeof(errmsg),
		     "The file to which the capture would be"
                     " saved (\"%s\") could not be opened: Error %d.",
 			cfile.save_file, err);
      } else {
        snprintf(errmsg, sizeof(errmsg),
		     "The file to which the capture would be"
                     " saved (\"%s\") could not be opened: %s.",
 			cfile.save_file, strerror(err));
      }
      break;
    }
    goto error;
  }

  /* Does "open_err_str" contain a non-empty string?  If so, "pcap_open_live()"
     returned a warning; print it, but keep capturing. */
  if (open_err_str[0] != '\0')
    g_warning("%s.", open_err_str);

  /* XXX - capture SIGTERM and close the capture, in case we're on a
     Linux 2.0[.x] system and you have to explicitly close the capture
     stream in order to turn promiscuous mode off?  We need to do that
     in other places as well - and I don't think that works all the
     time in any case, due to libpcap bugs. */

  if (capture_child) {
    /* Well, we should be able to start capturing.

       This is the child process for a sync mode capture, so sync out
       the capture file, so the header makes it to the file system,
       and send a "capture started successfully and capture file created"
       message to our parent so that they'll open the capture file and
       update its windows to indicate that we have a live capture in
       progress. */
    fflush(wtap_dump_file(ld.pdh));
    sync_pipe_capstart_to_parent();
  }

  /* start capture info dialog */
  if(show_info) {
      capture_ui.callback_data  = &ld;
      capture_ui.counts         = &ld.counts;
      capture_info_create(&capture_ui, cfile.iface);
  }

  start_time = time(NULL);
  upd_time = time(NULL);
#ifdef MUST_DO_SELECT
  if (!ld.from_cap_pipe) pcap_fd = pcap_fileno(pch);
#endif

#ifndef _WIN32
  /*
   * Catch SIGUSR1, so that we exit cleanly if the parent process
   * kills us with it due to the user selecting "Capture->Stop".
   */
  if (capture_child)
    signal(SIGUSR1, stop_capture_signal_handler);
#endif

  /* initialize capture stop conditions */
  init_capture_stop_conditions();
  /* create stop conditions */
  if (capture_opts.has_autostop_filesize)
    cnd_autostop_size =
        cnd_new(CND_CLASS_CAPTURESIZE,(long)capture_opts.autostop_filesize);
  if (capture_opts.has_autostop_duration)
    cnd_autostop_duration =
        cnd_new(CND_CLASS_TIMEOUT,(gint32)capture_opts.autostop_duration);

  if (capture_opts.multi_files_on) {
      if (capture_opts.has_file_duration)
        cnd_file_duration =
	    cnd_new(CND_CLASS_TIMEOUT, capture_opts.file_duration);

      if (capture_opts.has_autostop_files)
        cnd_autostop_files =
	    cnd_new(CND_CLASS_CAPTURESIZE, capture_opts.autostop_files);
  }

  /* WOW, everything is prepared! */
  /* please fasten your seat belts, we will enter now the actual capture loop */
  while (ld.go) {
    main_window_update();

#ifndef _WIN32
    if (ld.from_cap_pipe) {
      FD_ZERO(&set1);
      FD_SET(pipe_fd, &set1);
      timeout.tv_sec = 0;
      timeout.tv_usec = CAP_READ_TIMEOUT*1000;
      sel_ret = select(pipe_fd+1, &set1, NULL, NULL, &timeout);
      if (sel_ret <= 0) {
	inpkts = 0;
        if (sel_ret < 0 && errno != EINTR) {
          snprintf(errmsg, sizeof(errmsg),
            "Unexpected error from select: %s", strerror(errno));
          popup_errmsg(errmsg);
          ld.go = FALSE;
        }
      } else {
	/*
	 * "select()" says we can read from the pipe without blocking
	 */
	inpkts = cap_pipe_dispatch(pipe_fd, &ld, &hdr, &rechdr, pcap_data,
          errmsg, sizeof errmsg);
	if (inpkts < 0) {
	  ld.go = FALSE;
        }
      }
    }
    else
#endif /* _WIN32 */
    {
#ifdef MUST_DO_SELECT
      /*
       * Sigh.  The semantics of the read timeout argument to
       * "pcap_open_live()" aren't particularly well specified by
       * the "pcap" man page - at least with the BSD BPF code, the
       * intent appears to be, at least in part, a way of cutting
       * down the number of reads done on a capture, by blocking
       * until the buffer fills or a timer expires - and the Linux
       * libpcap doesn't actually support it, so we can't use it
       * to break out of the "pcap_dispatch()" every 1/4 of a second
       * or so.  Linux's libpcap is not the only libpcap that doesn't
       * support the read timeout.
       *
       * Furthermore, at least on Solaris, the bufmod STREAMS module's
       * read timeout won't go off if no data has arrived, i.e. it cannot
       * be used to guarantee that a read from a DLPI stream will return
       * within a specified amount of time regardless of whether any
       * data arrives or not.
       *
       * Thus, on all platforms other than BSD, we do a "select()" on the
       * file descriptor for the capture, with a timeout of CAP_READ_TIMEOUT
       * milliseconds, or CAP_READ_TIMEOUT*1000 microseconds.
       *
       * "select()", on BPF devices, doesn't work as you might expect;
       * at least on some versions of some flavors of BSD, the timer
       * doesn't start until a read is done, so it won't expire if
       * only a "select()" or "poll()" is posted.
       */
      FD_ZERO(&set1);
      FD_SET(pcap_fd, &set1);
      timeout.tv_sec = 0;
      timeout.tv_usec = CAP_READ_TIMEOUT*1000;
      sel_ret = select(pcap_fd+1, &set1, NULL, NULL, &timeout);
      if (sel_ret > 0) {
	/*
	 * "select()" says we can read from it without blocking; go for
	 * it.
	 */
	inpkts = pcap_dispatch(pch, 1, capture_pcap_cb, (guchar *) &ld);
	if (inpkts < 0) {
	  ld.pcap_err = TRUE;
	  ld.go = FALSE;
	}
      } else {
        inpkts = 0;
        if (sel_ret < 0 && errno != EINTR) {
          snprintf(errmsg, sizeof(errmsg),
            "Unexpected error from select: %s", strerror(errno));
          popup_errmsg(errmsg);
          ld.go = FALSE;
        }
      }
#else
      inpkts = pcap_dispatch(pch, 1, capture_pcap_cb, (guchar *) &ld);
      if (inpkts < 0) {
        ld.pcap_err = TRUE;
        ld.go = FALSE;
      }
#endif /* MUST_DO_SELECT */
    }

    if (inpkts > 0) {
      ld.sync_packets += inpkts;

      /* check capture size condition */
      if (cnd_autostop_size != NULL && cnd_eval(cnd_autostop_size,
                    (guint32)wtap_get_bytes_dumped(ld.pdh))){
        /* Capture size limit reached, do we have another file? */
        if (capture_opts.multi_files_on) {
          if (cnd_autostop_files != NULL && cnd_eval(cnd_autostop_files, ++autostop_files)) {
            /* no files left: stop here */
            ld.go = FALSE;
            continue;
          }

          /* Switch to the next ringbuffer file */
          if (ringbuf_switch_file(&cfile, &ld.pdh, &ld.err)) {
            /* File switch succeeded: reset the conditions */
            cnd_reset(cnd_autostop_size);
            if (cnd_file_duration) {
              cnd_reset(cnd_file_duration);
            }
          } else {
            /* File switch failed: stop here */
            ld.go = FALSE;
            continue;
          }
        } else {
          /* single file, stop now */
          ld.go = FALSE;
          continue;
        }
      } /* cnd_autostop_size */
    }

    /* Only update once a second so as not to overload slow displays */
    cur_time = time(NULL);
    if (cur_time > upd_time) {
      upd_time = cur_time;

      /*if (pcap_stats(pch, stats) >= 0) {
        *stats_known = TRUE;
      }*/

      	/* Let the parent process know. */
      /* calculate and display running time */
      if(show_info) {
          cur_time -= start_time;
          capture_ui.running_time   = cur_time;
          capture_ui.new_packets    = ld.sync_packets;
          capture_info_update(&capture_ui);
      }

      if (ld.sync_packets) {
        /* do sync here */
        fflush(wtap_dump_file(ld.pdh));

        if (capture_child) {
	  /* This is the child process for a sync mode capture, so send
	     our parent a message saying we've written out "ld.sync_packets"
	     packets to the capture file. */
        sync_pipe_packet_count_to_parent(ld.sync_packets);
        }

        ld.sync_packets = 0;
      }

      /* check capture duration condition */
      if (cnd_autostop_duration != NULL && cnd_eval(cnd_autostop_duration)) {
        /* The maximum capture time has elapsed; stop the capture. */
        ld.go = FALSE;
        continue;
      }
      
      /* check capture file duration condition */
      if (cnd_file_duration != NULL && cnd_eval(cnd_file_duration)) {
        /* duration limit reached, do we have another file? */
        if (capture_opts.multi_files_on) {
          if (cnd_autostop_files != NULL && cnd_eval(cnd_autostop_files, ++autostop_files)) {
            /* no files left: stop here */
            ld.go = FALSE;
            continue;
          }

          /* Switch to the next ringbuffer file */
          if (ringbuf_switch_file(&cfile, &ld.pdh, &ld.err)) {
            /* file switch succeeded: reset the conditions */
            cnd_reset(cnd_file_duration);
            if(cnd_autostop_size)
              cnd_reset(cnd_autostop_size);
          } else {
            /* File switch failed: stop here */
	        ld.go = FALSE;
            continue;
          }
        } else {
          /* single file, stop now */
          ld.go = FALSE;
          continue;
        }
      } /* cnd_file_duration */
    }

  } /* while (ld.go) */

  /* delete stop conditions */
  if (cnd_file_duration != NULL)
    cnd_delete(cnd_file_duration);
  if (cnd_autostop_files != NULL)
    cnd_delete(cnd_autostop_files);
  if (cnd_autostop_size != NULL)
    cnd_delete(cnd_autostop_size);
  if (cnd_autostop_duration != NULL)
    cnd_delete(cnd_autostop_duration);

  if (ld.pcap_err) {
    snprintf(errmsg, sizeof(errmsg), "Error while capturing packets: %s",
      pcap_geterr(pch));
    popup_errmsg(errmsg);
#ifdef _WIN32
  }
#else
  } else if (ld.from_cap_pipe && ld.cap_pipe_err == PIPERR)
      popup_errmsg(errmsg);
#endif

  if (ld.err == 0)
    write_ok = TRUE;
  else {
    get_capture_file_io_error(errmsg, sizeof(errmsg), cfile.save_file, ld.err,
			      FALSE);
    popup_errmsg(errmsg);
    write_ok = FALSE;
  }

  if (capture_opts.multi_files_on) {
    close_ok = ringbuf_wtap_dump_close(&cfile, &err);
  } else {
    close_ok = wtap_dump_close(ld.pdh, &err);
  }
  /* If we've displayed a message about a write error, there's no point
     in displaying another message about an error on close. */
  if (!close_ok && write_ok) {
    get_capture_file_io_error(errmsg, sizeof(errmsg), cfile.save_file, err,
		TRUE);
    popup_errmsg(errmsg);
  }
  /* Set write_ok to mean the write and the close were successful. */
  write_ok = (write_ok && close_ok);

#ifndef _WIN32
  /*
   * XXX We exhibit different behaviour between normal mode and sync mode
   * when the pipe is stdin and not already at EOF.  If we're a child, the
   * parent's stdin isn't closed, so if the user starts another capture,
   * cap_pipe_open_live() will very likely not see the expected magic bytes and
   * will say "Unrecognized libpcap format".  On the other hand, in normal
   * mode, cap_pipe_open_live() will say "End of file on pipe during open".
   */
  if (ld.from_cap_pipe && pipe_fd >= 0)
    close(pipe_fd);
  else
#endif
  {
    /* Get the capture statistics, so we know how many packets were
       dropped. */
    if (pcap_stats(pch, stats) >= 0) {
      *stats_known = TRUE;
      if (capture_child) {
      	/* Let the parent process know. */
        sync_pipe_drops_to_parent(stats->ps_drop);
      }
    } else {
      snprintf(errmsg, sizeof(errmsg),
		"Can't get packet-drop statistics: %s",
		pcap_geterr(pch));
      popup_errmsg(errmsg);
    }
    pcap_close(pch);
  }

#ifdef _WIN32
  /* Shut down windows sockets */
  WSACleanup();
#endif

  if(show_info) {
    capture_info_destroy(&capture_ui);
  }

  return write_ok;

error:
  if (capture_opts.multi_files_on) {
    /* cleanup ringbuffer */
    ringbuf_error_cleanup();
  } else {
    /* We can't use the save file, and we have no wtap_dump stream
       to close in order to close it, so close the FD directly. */
    close(cfile.save_file_fd);

    /* We couldn't even start the capture, so get rid of the capture
       file. */
    unlink(cfile.save_file); /* silently ignore error */
    g_free(cfile.save_file);
  }
  cfile.save_file = NULL;
  popup_errmsg(errmsg);

#ifndef _WIN32
  if (ld.from_cap_pipe) {
    if (pipe_fd >= 0)
      close(pipe_fd);
  } else
#endif
  {
    if (pch != NULL)
      pcap_close(pch);
  }

  return FALSE;
}

static void
get_capture_file_io_error(char *errmsg, int errmsglen, const char *fname,
			  int err, gboolean is_close)
{
  switch (err) {

  case ENOSPC:
    snprintf(errmsg, errmsglen,
		"Not all the packets could be written to the file"
		" to which the capture was being saved\n"
		"(\"%s\") because there is no space left on the file system\n"
		"on which that file resides.",
		fname);
    break;

#ifdef EDQUOT
  case EDQUOT:
    snprintf(errmsg, errmsglen,
		"Not all the packets could be written to the file"
		" to which the capture was being saved\n"
		"(\"%s\") because you are too close to, or over,"
		" your disk quota\n"
		"on the file system on which that file resides.",
		fname);
  break;
#endif

  case WTAP_ERR_CANT_CLOSE:
    snprintf(errmsg, errmsglen,
		"The file to which the capture was being saved"
		" couldn't be closed for some unknown reason.");
    break;

  case WTAP_ERR_SHORT_WRITE:
    snprintf(errmsg, errmsglen,
		"Not all the packets could be written to the file"
		" to which the capture was being saved\n"
		"(\"%s\").",
		fname);
    break;

  default:
    if (is_close) {
      snprintf(errmsg, errmsglen,
		"The file to which the capture was being saved\n"
		"(\"%s\") could not be closed: %s.",
		fname, wtap_strerror(err));
    } else {
      snprintf(errmsg, errmsglen,
		"An error occurred while writing to the file"
		" to which the capture was being saved\n"
		"(\"%s\"): %s.",
		fname, wtap_strerror(err));
    }
    break;
  }
}

static void
popup_errmsg(const char *errmsg)
{
  if (capture_child) {
    /* This is the child process for a sync mode capture.
       Send the error message to our parent, so they can display a
       dialog box containing it. */
    sync_pipe_errmsg_to_parent(errmsg);
  } else {
    /* Display the dialog box ourselves; there's no parent. */
    simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "%s", errmsg);
  }
}

static void
stop_capture_signal_handler(int signo _U_)
{
  ld.go = FALSE;
}


void
capture_stop(void)
{

  if (capture_opts.sync_mode) {	
      sync_pipe_stop();
  } else {
      ld.go = FALSE;
  }
}

void
kill_capture_child(void)
{
  if (capture_opts.sync_mode) {	
    sync_pipe_kill();
  }
}

/* one packet was captured, process it */
static void
capture_pcap_cb(guchar *user, const struct pcap_pkthdr *phdr,
  const guchar *pd)
{
  struct wtap_pkthdr whdr;
  union wtap_pseudo_header pseudo_header;
  loop_data *ld = (loop_data *) user;
  int err;

  /* user told us to stop after x packets, do we have enough? */
  if ((++ld->counts.total >= ld->max) && (ld->max > 0))
  {
     ld->go = FALSE;
  }

  /* Convert from libpcap to Wiretap format.
     If that fails, set "ld->go" to FALSE, to stop the capture, and set
     "ld->err" to the error. */
  pd = wtap_process_pcap_packet(ld->linktype, phdr, pd, &pseudo_header,
				&whdr, &err);
  if (pd == NULL) {
    ld->go = FALSE;
    ld->err = err;
    return;
  }

  if (ld->pdh) {
    /* We're supposed to write the packet to a file; do so.
       If this fails, set "ld->go" to FALSE, to stop the capture, and set
       "ld->err" to the error. */
    if (!wtap_dump(ld->pdh, &whdr, &pseudo_header, pd, &err)) {
      ld->go = FALSE;
      ld->err = err;
    }
  }

  switch (ld->linktype) {
    case WTAP_ENCAP_ETHERNET:
      capture_eth(pd, 0, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_FDDI:
    case WTAP_ENCAP_FDDI_BITSWAPPED:
      capture_fddi(pd, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_PRISM_HEADER:
      capture_prism(pd, 0, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_TOKEN_RING:
      capture_tr(pd, 0, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_NULL:
      capture_null(pd, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_PPP:
      capture_ppp_hdlc(pd, 0, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_RAW_IP:
      capture_raw(pd, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_SLL:
      capture_sll(pd, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_LINUX_ATM_CLIP:
      capture_clip(pd, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_IEEE_802_11:
    case WTAP_ENCAP_IEEE_802_11_WITH_RADIO:
      capture_ieee80211(pd, 0, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_CHDLC:
      capture_chdlc(pd, 0, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_LOCALTALK:
      capture_llap(&ld->counts);
      break;
    case WTAP_ENCAP_ATM_PDUS:
      capture_atm(&pseudo_header, pd, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_IP_OVER_FC:
      capture_ipfc(pd, whdr.caplen, &ld->counts);
      break;
    case WTAP_ENCAP_ARCNET:
      capture_arcnet(pd, whdr.caplen, &ld->counts, FALSE, TRUE);
      break;
    case WTAP_ENCAP_ARCNET_LINUX:
      capture_arcnet(pd, whdr.caplen, &ld->counts, TRUE, FALSE);
      break;
    case WTAP_ENCAP_APPLE_IP_OVER_IEEE1394:
      capture_ap1394(pd, 0, whdr.caplen, &ld->counts);
      break;
    /* XXX - some ATM drivers on FreeBSD might prepend a 4-byte ATM
       pseudo-header to DLT_ATM_RFC1483, with LLC header following;
       we might have to implement that at some point. */
  }
}

#endif /* HAVE_LIBPCAP */