Hi,
Ok, I read through the documents but now I think it is not possible to realize my "problem"/task in wireshark.
I have a communication on 2-3 channels, ok therefor I could use conversations. But I want also that I can calculate the next expected frame on e.g. channel 1, therefor I extract the actual frame number out of frame n and increase it (="next calculated frame number"). Then I´ll compare the calculated frame number with the frame number of the next received frame n+1 on channel 1. But because of the random access of the capture file I do not know whether the "next calculated frame number" should be the same like the actual frame n+i. I couldn´t find out if the last dissected packet (where I calculate the "next calculated frame number") was really the predecessor of my actual frame. With the help of timestamps I can find out if the last dissected packet was A predecessor but not if it was THE predecessor of my actual frame. I could also check, if frame n-1 was already visited, but that doesn´t helps, too.
Am I wrong or is there a possibility?
Regards and Thanks
Chris
----- Ursprüngliche Mail ----
Von: Jaap Keuter <jaap.keuter@xxxxxxxxx>
An: Developer support list for Wireshark <wireshark-dev@xxxxxxxxxxxxx>
Gesendet: Montag, den 30. Juni 2008, 19:44:30 Uhr
Betreff: Re: [Wireshark-dev] Dissector global variable
Hi,
A global variable won't work for two reasons:
1. The capture file is accessed randomly.
2. You might have multiple exchanges you need to follow.
To tackle point 2 you can use conversations. Read about them in
README.developer. To collect and keep track of protocol data across packets
have a look at README.request_response_tracking.
Thanx,
Jaap
Hans Glück wrote:
> Hello,
>
> I´m writing a dissector and I want to implement "error recovery mode"/"flow control", therefor I need two gloabl variables where I can store some values (-> "next_expected_frame_to_be_recieved" and "next_expected_frame_to_be_send").
> I declared them at the beginning of my c-file:
> static guint8 next_expected_frame_to_be_recieved = 0;
> static guint8 next_expected_frame_to_be_send = 0;
>
> And I set value of this variables in my dissector code:
> static void dissect_mux27010(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree){
> ...
> if (received_successful()) {
> next_expected_frame_to_be_recieved++;
> }
> ...
> }
>
> My problem is: Every time I click in Wireshark at packet the value is increased e.g.
> click first packet -> next_expected_frame_to_be_recieved == 1
> click second packet -> next_expected_frame_to_be_recieved == 2
> click first packet -> next_expected_frame_to_be_recieved == 3
> click second packet -> next_expected_frame_to_be_recieved == 4
>
> But what I want is that the variables are increased step-by-step/ ordered (if packet n is an ACK -> increase; if packet n+1 is an ACK -> increase...)
> How can I realize this?
>
> Thanks for any advice.
> Chris
>
_______________________________________________
Wireshark-dev mailing list
Wireshark-dev@xxxxxxxxxxxxx
https://wireshark.org/mailman/listinfo/wireshark-dev
__________________________________________________________
Gesendet von Yahoo! Mail.
Dem pfiffigeren Posteingang.
http://de.overview.mail.yahoo.com
