Wireshark · Ethereal-dev: [Ethereal-dev] Changing tap code not to call "epan_dissect_run()" one more time?

["Pia Sahlberg" <piabar@xxxxxxxxxxx>]

Hi list, hi guy.

I agree 100% that doing two dissections is bad and should be eliminated.

However, I would prefer a different approach.

I think it would be cleaner if the code was changed instead so that
in file.c   the display/color-filter handling itself would become
tap extensions.

For example: display-filter could be changed to be a 10 line tap extension 
that just changes a global variable.
Then,  in file.c (analog in tethereal.c)   display filter handling would 
just be

filter_passed=0;
<do the tap calls>
if(filter_passed or no-filter-at-all){
} else {
}

Display filter would just be a tap extension, registered on the "frame" tap 
with no draw or reset callback, and one packet callback:
df_packet(){
  filter_passed=1;
}

This would basically remove all the display filter code from tap.c and 
tethereal.c   and reuse the facilities of tap.


We could do a similar thing with color-filters. I.e. chganging them to 
really simple tap extensions that just change a global fg/bg variable when 
invoked.


With these two changes implemented, we have removed ALL filter handling from 
file.c (except the read-filter one, but i think it is semi-broken anyway 
since it calls the dissectors with frame-num==0 for all packets and 
reassembly and friends will be unhappy with that)

Since ALL filter handling has been removed from file.c   we can fold the
two functions tap_queue_init() and tap_push_tapped_queue() into a single
fiunction and rename it to tap_dissect_packet() which would unconditionally 
dissect the packet exactly once.


This would remove lots of code handling filters from file.c, code that by 
nessecity must be duplicated inside tap.c anyway for tap to work.
We would be back at always, no matter what, packets are dissected exactly 
once, and not as now, twice if there are taps.


I want to make this change but life and travel has interfered.

best regards







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