Ethereal-dev: Re: [Ethereal-dev] access to previous packet data

Note: This archive is from the project's previous web site, ethereal.com. This list is no longer active.

Date Index Thread Index Other Months All Mailing Lists
Date Prev Date Next Thread Prev Thread Next
From: Patrick Fuchs <rotfuchs@xxxxxxxxxxxxxxxxxxxxx>
Date: Tue, 21 Mar 2006 20:50:27 +0100
Guy Harris schrieb:

rotfuchs@xxxxxxxxxxxxxxxxxxxxx wrote:


is it possible to access data from a previous
per_packet_data_structure? I tried it with      "prev_frame_data =
p_get_proto_data(pinfo->fd->prev, proto_iec);"

Should this work


I'd expect it to work *IF*

    1) there *is* a previous frame (i.e., pinfo->fd->prev is not null)

and

    2) that frame has a per-packet data structure for the IEC protocol
associated with it.

Note that pinfo->fd->prev refers to the previous packet in the capture,
not the previous packet with a proto_iec item in it.

Ok, i see the problem!


or am i barking up the wrong tree?


You might be - you might, for example, want to do whatever you're doing
with a per-conversation data structure plus per-packet data structures. What is it you're trying to do?
I want to compare some data from the actual packet with data from the previous packet.I built up a convesation and i could implement a structure with two variables e.g. data and prev_data and copying the data to prev_data in every new packet. But is there also a possibilty to access per-packet-data from the previous packet in the conversation, or rather store per-packet-data for a conversation? 

Thank you, for your help.