Add remove_last_data_source and fix bug 9169

The OP asked 9169 to be reopened because the capture was spewing ~40GB of output
when dissected with tshark. Investigation showed this was because the HTTP
dissector was requesting ONE_MORE_PACKET reassembly a lot, and TCP was adding
each step as a data-source which was being printed by tshark's hex dump. This
was leading to O(n^2) of output.

To fix, introduce function remove_last_data_source which removes the most recent
data source from the list. If the subdissector in TCP reassembly asks for
ONE_MORE_PACKET, assume it hasn't added any tree items (since it shouldn't have)
and remove the data source since it is unnecessary.

This may break dissectors which add tree items and *then* return
ONE_MORE_PACKET, since they will have their data source removed out from under
them. I believe those cases should be fixed to not add tree items until they're
sure they have enough data.

Change-Id: Iff07f959b8b8bd1acda9bff03f7c8684901ba8aa
Reviewed-on: https://code.wireshark.org/review/38
Reviewed-by: Evan Huus <eapache@gmail.com>
Tested-by: Evan Huus <eapache@gmail.com>

0 files changed, 0 insertions, 0 deletions