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
|
<!-- WSUG Appendix Tools -->
<!-- $Id$ -->
<appendix id="AppTools">
<title>Related command line tools</title>
<section id="AppToolsIntroduction">
<title>Introduction</title>
<para>
Besides the Wireshark GUI application, there are some command line tools
which can be helpful for doing some more specialized things. These tools
will be described in this chapter.
</para>
</section>
<section id="AppToolstshark">
<title><command>tshark</command>: Terminal-based Wireshark</title>
<para>
<application>TShark</application> is a terminal oriented version
of Wireshark designed for capturing and displaying packets when an
interactive user interface isn't necessary or available. It supports
the same options as <command>wireshark</command>. For more
information on <command>tshark</command>, see the manual pages
(<command>man tshark</command>).
</para>
</section>
<section id="AppToolstcpdump">
<title><command>tcpdump</command>: Capturing with tcpdump for viewing
with Wireshark</title>
<para>
There are occasions when you want to capture packets using
<command>tcpdump</command> rather than <command>wireshark</command>,
especially when you want to do a remote capture and do not want the
network load associated with running Wireshark remotely (not to
mention all the X traffic polluting your capture).
</para>
<para>
However, the default <command>tcpdump</command> parameters result in a
capture file where each packet is truncated, because most versions of
<command>tcpdump</command>, will, by default, only capture the first
68 or 96 bytes of each packet.
</para>
<para>
To ensure that you capture complete packets, use the following command:
<programlisting>
tcpdump -i <interface> -s 65535 -w <some-file>
</programlisting>
You will have to specify the correct <command>interface</command> and
the name of a <command>file</command> to save into. In addition,
you will have to terminate the capture with ^C when you believe you
have captured enough packets.
</para>
<note><title>Note!</title>
<para>
tcpdump is not part of the Wireshark distribution. You can get it from:
<ulink url="&TcpdumpWebsite;">&TcpdumpWebsite;</ulink> for various
platforms.
</para>
</note>
</section>
<section id="AppToolsdumpcap">
<title><command>dumpcap</command>: Capturing with dumpcap for viewing
with Wireshark</title>
<para>
<application>Dumpcap</application> is a network traffic dump tool.
It captures packet data from a live network and writes the
packets to a file.
Dumpcap's native capture file format is libpcap format, which is also
the format used by Wireshark, tcpdump and various other tools.
</para>
<para>
Without any options set it will use the pcap library to capture traffic
from the first available network interface and write the received raw
packet data, along with the packets' time stamps into a libpcap file.
</para>
<para>
Packet capturing is performed with the pcap library.
The capture filter syntax follows the rules of the pcap library.
</para>
<para>
<example id="AppToolsdumpcapEx">
<title>Help information available from dumpcap</title>
<programlisting>
dumpcap -h
Dumpcap 1.1.4
Capture network packets and dump them into a libpcap file.
See http://www.wireshark.org for more information.
Usage: dumpcap [options] ...
Capture interface:
-i <interface> name or idx of interface (def: first non-loopback)
-f <capture filter> packet filter in libpcap filter syntax
-s <snaplen> packet snapshot length (def: 65535)
-p don't capture in promiscuous mode
-B <buffer size> size of kernel buffer (def: 1MB)
-y <link type> link layer type (def: first appropriate)
-D print list of interfaces and exit
-L print list of link-layer types of iface and exit
-S print statistics for each interface once every second
-M for -D, -L, and -S produce machine-readable output
Stop conditions:
-c <packet count> stop after n packets (def: infinite)
-a <autostop cond.> ... duration:NUM - stop after NUM seconds
filesize:NUM - stop this file after NUM KB
files:NUM - stop after NUM files
Output (files):
-w <filename> name of file to save (def: tempfile)
-b <ringbuffer opt.> ... duration:NUM - switch to next file after NUM secs
filesize:NUM - switch to next file after NUM KB
files:NUM - ringbuffer: replace after NUM files
-n use pcapng format instead of pcap
Miscellaneous:
-v print version information and exit
-h display this help and exit
Example: dumpcap -i eth0 -a duration:60 -w output.pcap
"Capture network packets from interface eth0 until 60s passed into output.pcap"
Use Ctrl-C to stop capturing at any time.
</programlisting>
</example>
</para>
</section>
<section id="AppToolscapinfos">
<title><command>capinfos</command>: Print information about capture files
</title>
<para>
Included with Wireshark is a small utility called
<command>capinfos</command>, which is a command-line utility to
print information about binary capture files.
</para>
<para>
<example id="AppToolscapinfosEx">
<title>Help information available from capinfos</title>
<programlisting>
$ capinfos -h
Capinfos 1.1.4
Prints information about capture files.
See http://www.wireshark.org for more information.
Usage: capinfos [options] <infile> ...
General:
-t display the capture file type
-E display the capture file encapsulation
Size:
-c display the number of packets
-s display the size of the file (in bytes)
-d display the total length of all packets (in bytes)
Time:
-u display the capture duration (in seconds)
-a display the capture start time
-e display the capture end time
Statistic:
-y display average data rate (in bytes/sec)
-i display average data rate (in bits/sec)
-z display average packet size (in bytes)
-x display average packet rate (in packets/sec)
Miscellaneous:
-h display this help and exit
If no options are given the default is to display all infos
</programlisting>
</example>
</para>
</section>
<section id="AppToolseditcap">
<title><command>editcap</command>: Edit capture files</title>
<para>
Included with Wireshark is a small utility called
<command>editcap</command>, which is a command-line utility for
working with capture files. Its main function is to remove
packets from capture files, but it can also be used to convert
capture files from one format to another, as well as to print
information about capture files.
</para>
<para>
<example id="AppToolseditcapEx">
<title>Help information available from editcap</title>
<para>
<programlisting>
$ editcap -h
Editcap 1.1.4
Edit and/or translate the format of capture files.
See http://www.wireshark.org for more information.
Usage: editcap [options] ... <infile> <outfile> [ <packet#>[-<packet#>] ... ]
<infile> and <outfile> must both be present.
A single packet or a range of packets can be selected.
Packet selection:
-r keep the selected packets; default is to delete them.
-A <start time> don't output packets whose timestamp is before the
given time (format as YYYY-MM-DD hh:mm:ss).
-B <stop time> don't output packets whose timestamp is after the
given time (format as YYYY-MM-DD hh:mm:ss).
Duplicate packet removal:
-d remove packet if duplicate (window == 5).
-D <dup window> remove packet if duplicate; configurable <dup window>
Valid <dup window> values are 0 to 1000000.
NOTE: A <dup window> of 0 with -v (verbose option) is
useful to print MD5 hashes.
-w <dup time window> remove packet if duplicate packet is found EQUAL TO OR
LESS THAN <dup time window> prior to current packet.
A <dup time window> is specified in relative seconds
(e.g. 0.000001).
NOTE: The use of the 'Duplicate packet removal' options with
other editcap options except -v may not always work as expected.
Specifically the -r and -t options will very likely NOT have the
desired effect if combined with the -d, -D or -w.
Packet manipulation:
-s <snaplen> truncate each packet to max. <snaplen> bytes of data.
-C <choplen> chop each packet at the end by <choplen> bytes.
-t <time adjustment> adjust the timestamp of each packet;
<time adjustment> is in relative seconds (e.g. -0.5).
-E <error probability> set the probability (between 0.0 and 1.0 incl.)
that a particular packet byte will be randomly changed.
Output File(s):
-c <packets per file> split the packet output to different files
based on uniform packet counts
with a maximum of <packets per file> each.
-i <seconds per file> split the packet output to different files
based on uniform time intervals
with a maximum of <seconds per file> each.
-F <capture type> set the output file type; default is libpcap.
an empty "-F" option will list the file types.
-T <encap type> set the output file encapsulation type;
default is the same as the input file.
an empty "-T" option will list the encapsulation types.
Miscellaneous:
-h display this help and exit.
-v verbose output.
If -v is used with any of the 'Duplicate Packet
Removal' options (-d, -D or -w) then Packet lengths
and MD5 hashes are printed to standard-out.
</programlisting>
</para>
</example>
<example id="AppToolseditcapEx1">
<title>Capture file types available from editcap</title>
<para>
<programlisting>
$ editcap -F
editcap: option requires an argument -- F
editcap: The available capture file types for "F":
libpcap - Wireshark/tcpdump/... - libpcap
nseclibpcap - Wireshark - nanosecond libpcap
modlibpcap - Modified tcpdump - libpcap
nokialibpcap - Nokia tcpdump - libpcap
rh6_1libpcap - RedHat 6.1 tcpdump - libpcap
suse6_3libpcap - SuSE 6.3 tcpdump - libpcap
5views - Accellent 5Views capture
dct2000 - Catapult DCT2000 trace (.out format)
nettl - HP-UX nettl trace
netmon1 - Microsoft NetMon 1.x
netmon2 - Microsoft NetMon 2.x
ngsniffer - NA Sniffer (DOS)
ngwsniffer_1_1 - NA Sniffer (Windows) 1.1
ngwsniffer_2_0 - NA Sniffer (Windows) 2.00x
niobserverv9 - Network Instruments Observer (V9)
lanalyzer - Novell LANalyzer
snoop - Sun snoop
rf5 - Tektronix K12xx 32-bit .rf5 format
visual - Visual Networks traffic capture
k12text - K12 text file
commview - TamoSoft CommView
pcapng - Wireshark - pcapng (experimental)
</programlisting>
</para>
</example>
<example id="AppToolseditcapEx2">
<title>Encapsulation types available from editcap</title>
<para></para>
</example>
<!-- This kludge is needed since example doesn't break across PDF pages -->
<informalexample>
<para>
<programlisting>
$ editcap -T
editcap: option requires an argument -- T
editcap: The available encapsulation types for "T":
ether - Ethernet
tr - Token Ring
slip - SLIP
ppp - PPP
fddi - FDDI
fddi-swapped - FDDI with bit-swapped MAC addresses
rawip - Raw IP
arcnet - ARCNET
arcnet_linux - Linux ARCNET
atm-rfc1483 - RFC 1483 ATM
linux-atm-clip - Linux ATM CLIP
lapb - LAPB
atm-pdus - ATM PDUs
atm-pdus-untruncated - ATM PDUs - untruncated
null - NULL
ascend - Lucent/Ascend access equipment
isdn - ISDN
ip-over-fc - RFC 2625 IP-over-Fibre Channel
ppp-with-direction - PPP with Directional Info
ieee-802-11 - IEEE 802.11 Wireless LAN
prism - IEEE 802.11 plus Prism II monitor mode header
ieee-802-11-radio - IEEE 802.11 Wireless LAN with radio information
ieee-802-11-radiotap - IEEE 802.11 plus radiotap WLAN header
ieee-802-11-avs - IEEE 802.11 plus AVS WLAN header
linux-sll - Linux cooked-mode capture
frelay - Frame Relay
frelay-with-direction - Frame Relay with Directional Info
chdlc - Cisco HDLC
ios - Cisco IOS internal
ltalk - Localtalk
pflog-old - OpenBSD PF Firewall logs, pre-3.4
hhdlc - HiPath HDLC
docsis - Data Over Cable Service Interface Specification
cosine - CoSine L2 debug log
whdlc - Wellfleet HDLC
sdlc - SDLC
tzsp - Tazmen sniffer protocol
enc - OpenBSD enc(4) encapsulating interface
pflog - OpenBSD PF Firewall logs
chdlc-with-direction - Cisco HDLC with Directional Info
bluetooth-h4 - Bluetooth H4
mtp2 - SS7 MTP2
mtp3 - SS7 MTP3
irda - IrDA
user0 - USER 0
user1 - USER 1
user2 - USER 2
user3 - USER 3
user4 - USER 4
user5 - USER 5
user6 - USER 6
user7 - USER 7
user8 - USER 8
user9 - USER 9
user10 - USER 10
user11 - USER 11
user12 - USER 12
user13 - USER 13
user14 - USER 14
user15 - USER 15
symantec - Symantec Enterprise Firewall
ap1394 - Apple IP-over-IEEE 1394
bacnet-ms-tp - BACnet MS/TP
raw-icmp-nettl - Raw ICMP with nettl headers
raw-icmpv6-nettl - Raw ICMPv6 with nettl headers
gprs-llc - GPRS LLC
juniper-atm1 - Juniper ATM1
juniper-atm2 - Juniper ATM2
redback - Redback SmartEdge
rawip-nettl - Raw IP with nettl headers
ether-nettl - Ethernet with nettl headers
tr-nettl - Token Ring with nettl headers
fddi-nettl - FDDI with nettl headers
unknown-nettl - Unknown link-layer type with nettl headers
mtp2-with-phdr - MTP2 with pseudoheader
juniper-pppoe - Juniper PPPoE
gcom-tie1 - GCOM TIE1
gcom-serial - GCOM Serial
x25-nettl - X25 with nettl headers
k12 - K12 protocol analyzer
juniper-mlppp - Juniper MLPPP
juniper-mlfr - Juniper MLFR
juniper-ether - Juniper Ethernet
juniper-ppp - Juniper PPP
juniper-frelay - Juniper Frame-Relay
juniper-chdlc - Juniper C-HDLC
juniper-ggsn - Juniper GGSN
lapd - LAPD
dct2000 - Catapult DCT2000
ber - ASN.1 Basic Encoding Rules
juniper-vp - Juniper Voice PIC
usb - Raw USB packets
ieee-802-16-mac-cps - IEEE 802.16 MAC Common Part Sublayer
raw-telnet-nettl - Raw telnet with nettl headers
usb-linux - USB packets with Linux header
mpeg - MPEG
ppi - Per-Packet Information header
erf - Endace Record File
bluetooth-h4 - Bluetooth H4 with linux header
sita-wan - SITA WAN packets
sccp - SS7 SCCP
bluetooth-hci - Bluetooth without transport layer
ipmb - Intelligent Platform Management Bus
wpan - IEEE 802.15.4 Wireless PAN
x2e-xoraya - X2E Xoraya
flexray - FlexRay
lin - Local Interconnect Network
most - Media Oriented Systems Transport
can20b - Controller Area Network 2.0B
layer1-event - EyeSDN Layer 1 event
x2e-serial - X2E serial line capture
i2c - I2C
wpan-nonask-phy - IEEE 802.15.4 Wireless PAN non-ASK PHY
tnef - Transport-Neutral Encapsulation Format
usb-linux-mmap - USB packets with Linux header and padding
gsm_um - GSM Um Interface
</programlisting>
</para>
</informalexample>
</para>
</section>
<section id="AppToolsmergecap">
<title><command>mergecap</command>:
Merging multiple capture files into one
</title>
<para>
Mergecap is a program that combines multiple saved capture files
into a single output file specified by the -w argument. Mergecap
knows how to read libpcap capture files, including those of tcpdump.
In addition, Mergecap can read capture files from snoop (including
Shomiti) and atmsnoop, LanAlyzer, Sniffer (compressed or
uncompressed), Microsoft Network Monitor, AIX's iptrace, NetXray,
Sniffer Pro, RADCOM's WAN/LAN analyzer, Lucent/Ascend router debug
output, HP-UX's nettl, and the dump output from Toshiba's ISDN
routers. There is no need to tell Mergecap what type of file you are
reading; it will determine the file type by itself. Mergecap is also
capable of reading any of these file formats if they are compressed
using gzip. Mergecap recognizes this directly from the file; the '.gz'
extension is not required for this purpose.
</para>
<para>
By default, it writes the capture file in libpcap format, and writes
all of the packets in the input capture files to the output file.
The -F flag can be used to specify the format in which to write the
capture file; it can write the file in libpcap format (standard
libpcap format, a modified format used by some patched versions of
libpcap, the format used by Red Hat Linux 6.1, or the format used
by SuSE Linux 6.3), snoop format, uncompressed Sniffer format,
Microsoft Network Monitor 1.x format, and the format used by
Windows-based versions of the Sniffer software.
</para>
<para>
Packets from the input files are merged in chronological order based
on each frame's timestamp, unless the -a flag is specified. Mergecap
assumes that frames within a single capture file are already stored
in chronological order. When the -a flag is specified, packets are
copied directly from each input file to the output file, independent
of each frame's timestamp.
</para>
<para>
If the -s flag is used to specify a snapshot length, frames in the
input file with more captured data than the specified snapshot length
will have only the amount of data specified by the snapshot length
written to the output file. This may be useful if the program that
is to read the output file cannot handle packets larger than a
certain size (for example, the versions of snoop in Solaris 2.5.1 and
Solaris 2.6 appear to reject Ethernet frames larger than the standard
Ethernet MTU, making them incapable of handling gigabit Ethernet
captures if jumbo frames were used).
</para>
<para>
If the -T flag is used to specify an encapsulation type, the
encapsulation type of the output capture file will be forced to
the specified type, rather than being the type appropriate to the
encapsulation type of the input capture file. Note that this merely
forces the encapsulation type of the output file to be the specified
type; the packet headers of the packets will not be translated from the
encapsulation type of the input capture file to the specified
encapsulation type (for example, it will not translate an Ethernet
capture to an FDDI capture if an Ethernet capture is read
and '-T fddi' is specified).
</para>
<example id="AppToolsmergecapEx">
<title>Help information available from mergecap</title>
<programlisting>
$ mergecap -h
Mergecap 1.1.4
Merge two or more capture files into one.
See http://www.wireshark.org for more information.
Usage: mergecap [options] -w <outfile>|- <infile> ...
Output:
-a concatenate rather than merge files.
default is to merge based on frame timestamps.
-s <snaplen> truncate packets to <snaplen> bytes of data.
-w <outfile>|- set the output filename to <outfile> or '-' for stdout.
-F <capture type> set the output file type; default is libpcap.
an empty "-F" option will list the file types.
-T <encap type> set the output file encapsulation type;
default is the same as the first input file.
an empty "-T" option will list the encapsulation types.
Miscellaneous:
-h display this help and exit.
-v verbose output.
</programlisting>
</example>
<para>
A simple example merging <filename>dhcp-capture.libpcap</filename>
and <filename>imap-1.libpcap</filename> into
<filename>outfile.libpcap</filename> is shown below.
</para>
<example id="AppToolsmergecapExSimple">
<title>Simple example of using mergecap</title>
<programlisting>$ mergecap -w outfile.libpcap dhcp-capture.libpcap imap-1.libpcap
</programlisting>
</example>
</section>
<section id="AppToolstext2pcap" >
<title><command>text2pcap</command>: Converting ASCII hexdumps to network
captures
</title>
<para>
There may be some occasions when you wish to convert a hex dump of some
network traffic into a libpcap file.</para>
<para>
<command>Text2pcap</command> is a program that reads in an ASCII hex
dump and writes the data described into a libpcap-style capture file.
text2pcap can read hexdumps with multiple packets in them, and build a
capture file of multiple packets. text2pcap is also capable of
generating dummy Ethernet, IP and UDP headers, in order to build fully
processable packet dumps from hexdumps of application-level data only.
</para>
<para>
Text2pcap understands a hexdump of the form generated by od -A x -t x1. In
other words, each byte is individually displayed and surrounded with a
space. Each line begins with an offset describing the position in the
file. The offset is a hex number (can also be octal - see -o), of
more than two hex digits. Here is a sample dump that text2pcap can
recognize:
</para>
<programlisting>
000000 00 e0 1e a7 05 6f 00 10 ........
000008 5a a0 b9 12 08 00 46 00 ........
000010 03 68 00 00 00 00 0a 2e ........
000018 ee 33 0f 19 08 7f 0f 19 ........
000020 03 80 94 04 00 00 10 01 ........
000028 16 a2 0a 00 03 50 00 0c ........
000030 01 01 0f 19 03 80 11 01 ........
</programlisting>
<para>
There is no limit on the width or number of bytes per line. Also the
text dump at the end of the line is ignored. Bytes/hex numbers can be
uppercase or lowercase. Any text before the offset is ignored,
including email forwarding characters '>'. Any lines of text
between the bytestring lines is ignored. The offsets are used to
track the bytes, so offsets must be correct. Any line which has only
bytes without a leading offset is ignored. An offset is recognized
as being a hex number longer than two characters. Any text after the
bytes is ignored (e.g. the character dump). Any hex numbers in this
text are also ignored. An offset of zero is indicative of starting a
new packet, so a single text file with a series of hexdumps can be
converted into a packet capture with multiple packets. Multiple
packets are read in with timestamps differing by one second each.
In general, short of these restrictions, text2pcap is pretty liberal
about reading in hexdumps and has been tested with a variety of mangled
outputs (including being forwarded through email multiple times,
with limited line wrap etc.)
</para>
<para>
There are a couple of other special features to note. Any line where
the first non-whitespace character is '#' will be ignored as a
comment. Any line beginning with #TEXT2PCAP is a directive and options
can be inserted after this command to be processed by text2pcap.
Currently there are no directives implemented; in the future, these
may be used to give more fine grained control on the dump and the
way it should be processed e.g. timestamps, encapsulation type etc.
</para>
<para>
Text2pcap also allows the user to read in dumps of application-level
data, by inserting dummy L2, L3 and L4 headers before each packet.
Possiblities include inserting headers such as Ethernet, Ethernet + IP,
Ethernet + IP + UDP, or Ethernet + Ip + TCP before each packet.
This allows Wireshark or any other full-packet decoder to handle these dumps.
</para>
<example id="AppToolstext2pcapEx">
<title>Help information available for text2pcap</title>
<programlisting>
$ text2pcap -h
Text2pcap 1.1.4
Generate a capture file from an ASCII hexdump of packets.
See http://www.wireshark.org for more information.
Usage: text2pcap [options] <infile> <outfile>
where <infile> specifies input filename (use - for standard input)
<outfile> specifies output filename (use - for standard output)
Input:
-o hex|oct|dec parse offsets as (h)ex, (o)ctal or (d)ecimal; default is hex.
-t <timefmt> treats the text before the packet as a date/time code;
the specified argument is a format string of the sort
supported by strptime.
Example: The time "10:15:14.5476" has the format code
"%H:%M:%S."
NOTE: The subsecond component delimiter must be given
(.) but no pattern is required; the remaining number
is assumed to be fractions of a second.
NOTE: Date/time fields from the current date/time are
used as the default for unspecified fields.
Output:
-l <typenum> link-layer type number; default is 1 (Ethernet).
See the file net/bpf.h for list of numbers.
Use this option if your dump is a complete hex dump
of an encapsulated packet and you wish to specify
the exact type of encapsulation.
Example: -l 7 for ARCNet packets.
-m <max-packet> max packet length in output; default is 64000
Prepend dummy header:
-e <l3pid> prepend dummy Ethernet II header with specified L3PID
(in HEX).
Example: -e 0x806 to specify an ARP packet.
-i <proto> prepend dummy IP header with specified IP protocol
(in DECIMAL).
Automatically prepends Ethernet header as well.
Example: -i 46
-u <srcp>,<destp> prepend dummy UDP header with specified
dest and source ports (in DECIMAL).
Automatically prepends Ethernet & IP headers as well.
Example: -u 1000 69 to make the packets look like TFTP/UDP packets.
-T <srcp>,<destp> prepend dummy TCP header with specified
dest and source ports (in DECIMAL).
Automatically prepends Ethernet & IP headers as well.
Example: -T 50,60
-s <srcp>,<dstp>,<tag> prepend dummy SCTP header with specified
dest/source ports and verification tag (in DECIMAL).
Automatically prepends Ethernet & IP headers as well.
Example: -s 30,40,34
-S <srcp>,<dstp>,<ppi> prepend dummy SCTP header with specified
dest/source ports and verification tag 0.
Automatically prepends a dummy SCTP DATA
chunk header with payload protocol identifier ppi.
Example: -S 30,40,34
Miscellaneous:
-h display this help and exit.
-d detailed debug of parser states.
-q generate no output at all (automatically turns off -d).
</programlisting>
</example>
</section>
<section id="AppToolsidl2wrs" >
<title><command>idl2wrs</command>:
Creating dissectors from CORBA IDL files
</title>
<para>
In an ideal world idl2wrs would be mentioned in the users guide
in passing and documented in the developers guide. As the
developers guide
has not yet been completed it will be documented here.
</para>
<section>
<title>What is it?</title>
<para>
As you have probably guessed from the name,
<command>idl2wrs</command> takes a
user specified IDL file and attempts to build a dissector that
can decode the IDL traffic over GIOP. The resulting file is
"C" code, that should compile okay as a Wireshark dissector.
</para>
<para>
<command>idl2wrs</command> basically parses the data struct given to
it by the omniidl compiler, and using the GIOP API available in
packet-giop.[ch], generates get_CDR_xxx calls to decode the
CORBA traffic on the wire.
</para>
<para>It consists of 4 main files.</para>
<variablelist>
<varlistentry><term><filename>README.idl2wrs</filename></term>
<listitem>
<para>This document</para>
</listitem>
</varlistentry>
<varlistentry><term><filename>wireshark_be.py</filename></term>
<listitem>
<para>The main compiler backend</para>
</listitem>
</varlistentry>
<varlistentry><term><filename>wireshark_gen.py</filename></term>
<listitem>
<para>A helper class, that generates the C code.</para>
</listitem>
</varlistentry>
<varlistentry><term><filename>idl2wrs</filename></term>
<listitem>
<para> A simple shell script wrapper that the end user should
use to generate the dissector from the IDL file(s).</para>
</listitem>
</varlistentry>
</variablelist>
</section>
<section>
<title>Why do this?</title>
<para>
It is important to understand what CORBA traffic looks
like over GIOP/IIOP, and to help build a tool that can assist
in troubleshooting CORBA interworking. This was especially the
case after seeing a lot of discussions about how particular
IDL types are represented inside an octet stream.
</para>
<para>
I have also had comments/feedback that this tool would be good for say
a CORBA class when teaching students what CORBA traffic looks like
"on the wire".
</para>
<para>
It is also COOL to work on a great Open Source project such as
the case with "Wireshark" (
<ulink url="&WiresharkWebSite;">&WiresharkWebSite;</ulink>
)
</para>
</section>
<section><title>How to use idl2wrs</title>
<para>
To use the idl2wrs to generate Wireshark dissectors, you
need the following:
</para>
<orderedlist>
<title>Prerequisites to using idl2wrs</title>
<listitem>
<para>
Python must be installed. See
<ulink url="http://python.org/"/>
</para>
</listitem>
<listitem>
<para>
omniidl from the the omniORB package must be available. See
<ulink url="http://omniorb.sourceforge.net/"/>
</para>
</listitem>
<listitem>
<para>
Of course you need Wireshark installed to compile the
code and tweak it if required. idl2wrs is part of the
standard Wireshark distribution
</para>
</listitem>
</orderedlist>
<para>
To use idl2wrs to generate an Wireshark dissector from an idl file
use the following procedure:
</para>
<orderedlist>
<title>
Procedure for converting a CORBA idl file into a Wireshark
dissector
</title>
<listitem>
<para>
To write the C code to stdout.
<programlisting>idl2wrs <your file.idl></programlisting>
e.g.: <programlisting>idl2wrs echo.idl</programlisting>
</para>
</listitem>
<listitem>
<para>
To write to a file, just redirect the output.
<programlisting>idl2wrs echo.idl > packet-test-idl.c</programlisting>
You may wish to comment out the register_giop_user_module() code
and that will leave you with heuristic dissection.
</para>
</listitem>
</orderedlist>
<para>
If you don't want to use the shell script wrapper, then try
steps 3 or 4 instead.</para>
<orderedlist continuation="continues">
<listitem>
<para>To write the C code to stdout.
<programlisting>Usage: omniidl -p ./ -b wireshark_be <your file.idl></programlisting>
e.g.:
<programlisting>omniidl -p ./ -b wireshark_be echo.idl</programlisting>
</para>
</listitem>
<listitem>
<para>
To write to a file, just redirect the output.
<programlisting>omniidl -p ./ -b wireshark_be echo.idl > packet-test-idl.c</programlisting>
You may wish to comment out the register_giop_user_module() code
and that will leave you with heuristic dissection.
</para>
</listitem>
<listitem>
<para>
Copy the resulting C code to subdirectory epan/dissectors/ inside your
Wireshark source directory.
<programlisting>cp packet-test-idl.c /dir/where/wireshark/lives/epan/dissectors/</programlisting>
The new dissector has to be added to Makefile.common in the same
directory. Look for the declaration CLEAN_DISSECTOR_SRC and add
the new dissector there. For example,
<programlisting>
CLEAN_DISSECTOR_SRC = \
packet-2dparityfec.c \
packet-3com-njack.c \
...
</programlisting>
becomes
<programlisting>
CLEAN_DISSECTOR_SRC = \
packet-test-idl.c \
packet-2dparityfec.c \
packet-3com-njack.c \
...
</programlisting>
</para>
<para>
For the next steps, go up to the top of your Wireshark source directory.
</para>
</listitem>
<listitem>
<para>Run configure
<programlisting>./configure (or ./autogen.sh)</programlisting>
</para>
</listitem>
<listitem>
<para> Compile the code
<programlisting>make</programlisting>
</para>
</listitem>
<listitem>
<para>Good Luck !!</para>
</listitem>
</orderedlist>
</section>
<section><title>TODO</title>
<orderedlist>
<listitem>
<para>
Exception code not generated (yet), but can be added manually.
</para>
</listitem>
<listitem>
<para>
Enums not converted to symbolic values (yet), but can be added
manually.
</para>
</listitem>
<listitem>
<para>Add command line options etc</para>
</listitem>
<listitem>
<para>More I am sure :-)</para>
</listitem>
</orderedlist>
</section>
<section><title>Limitations</title>
<para>
See the TODO list inside <filename>packet-giop.c</filename>
</para>
</section>
<section><title>Notes</title>
<orderedlist>
<listitem>
<para>
The "-p ./" option passed to omniidl indicates that the
wireshark_be.py and wireshark_gen.py are residing in the
current directory. This may need
tweaking if you place these files somewhere else.
</para>
</listitem>
<listitem>
<para>
If it complains about being unable to find some modules
(e.g. tempfile.py),
you may want to check if PYTHONPATH is set correctly.
On my Linux box, it is PYTHONPATH=/usr/lib/python2.4/
</para>
</listitem>
</orderedlist>
</section>
</section>
</appendix>
<!-- End of WSUG Appendix Tools -->
|