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Hi all

I have a PCAP containing a message with fields of type UTC timestamp (7-bytes in length - YYYYDDMMHHMMSS format). When Wireshark dissect this message it properly displays the timestamp like ex: 19991212121212. Where as when dissected using tshark (used to export to CSV files) it diplays like "Jun 20, 107456758 10:19:19.1386439036 IST". I am not sure what is the reason behind this. I also observed that if i use tshark to just dissect (without using options to export to CSV files) then the format looks fine.

I went through the man page for tshark and found that there is a option "-t" to specify the timestamp in the summary lines, i tried all the option but still observed same. Can anyone please let me know if i am missing something. I basically want both Wireshark GUI and tshark (used to export to CSV files) to display the same time format (UTC - 7-bytes in length - YYYYDDMMHHMMSS).

tshark command used to export fields to CSV files is as below. /usr/bin/tshark -T fields -E separator=, -E header=y -E aggregator=~ -E quote=d -e <list of="" fields=""> -n -r <filename> > /tmp/details.csv

Thank you

Kiran Kumar G

asked 03 Feb '16, 11:03

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Kiran Kumar G
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accept rate: 0%

Can you share a Pcap (Google Drive, Dropbox etc.) containing the frame with the data in question?

(04 Feb '16, 07:46) grahamb ♦

Hi Graham

Sorry for the delay in reply.

The message to be dissected and having issue is dissected using my custom plugin. If i share the pcap file will you be able to dissect it ?. Can you please let me know if any other info i can share with you for analysis ? (picture, dissection snapshot etc).

Regards Kiran Kumar G

(28 Mar '16, 07:13) Kiran Kumar G

Without the plugin as well we won't be able to see the results of the dissection.

As it's a custom plugin, can you share the code, or if not, the fragment that reads the data from the field and adds it to the dissection results.

(28 Mar '16, 07:23) grahamb ♦

Hi Graham

I am providing the requirement with the code snippet used to get this done. Also, i am providing the output and the issue observed.

Requirement: Need to export dissected output of a message into CSV file (all fields of a message). Problem Statement: Some of fields of these messages are 7 bytes UTC timestamp (7-bytes in length - YYYYDDMMHHMMSS format). When Wireshark dissect this message it properly displays the timestamp like ex: 19991212121212. Where as when dissected using tshark (used to export to CSV files) it diplays like "Jun 20, 107456758 10:19:19.1386439036 IST".

Code snippet: Following is the code which is used to extract the 7 bytes and display in UTC time format.

struct utc_time { guint16 year; guint8 month; guint8 day; guint8 hour; guint8 minute; guint8 seconds; };

void gd_dissect_UTC_time_data (tvbuff_t tvb, int offset, struct utc_time utc_time)

{

utc_time->year = tvb_get_ntohs(tvb, offset);.

utc_time->month = tvb_get_guint8(tvb,offset+2);

utc_time->day = tvb_get_guint8(tvb,offset+3);

utc_time->hour = tvb_get_guint8(tvb,offset+4);

utc_time->minute = tvb_get_guint8(tvb,offset+5);

utc_time->seconds = tvb_get_guint8(tvb,offset+6);

}

===========================================================

dissect_UTC_time_data (tvb, tvb_offset, &utc_time_data); proto_tree_add_time_format_value (gd_msg_tree, (temp_icd_proto_info_ptr->proto_hf_ptr[temp_msg_field_details_ptr->field_hf_ref_index].p_id), tvb, tvb_offset, temp_field_size, (nstime_t ) &utc_time_data, "%d%02d%02d%02d%02d%02d", utc_time_data.year, utc_time_data.month, utc_time_data.day, utc_time_data.hour, utc_time_data.minute, utc_time_data.seconds ); ===========================================================

Output: Displayed on Wireshark GUI. 1999121212121212 (YYYYDDMMHHMMSS)

Displayed when exported to CSV using tshark command. Feb 2, 590961086 22:29:56.1250822016 IST

It should have displayed like 1999121212121212 .. right ?

Please let me know if any more information is required.

Thank you. Kiran Kumar G

(30 Mar '16, 05:54) Kiran Kumar G

You can't simply cast utc_time_data to nstime_t and expect it to work in the call to proto_tree_add_time_format_value().

You'll have to create a variable of type nstime_t, set the members correctly and then pass a pointer to that variable into the call to proto_tree_add_time_format_value().

Even having done that, I'm not sure that tshark will print the time formatted as you want, report back what happens.

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answered 30 Mar '16, 08:11

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grahamb ♦
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question asked: 03 Feb '16, 11:03

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last updated: 30 Mar '16, 08:11

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