Introduces two new dissector tables can.id and can.extended_id to enable a
more precise control of subdissectors dependent on the can id which is often
used to identify the the payload.
Since standard CAN IDs and extended IDs can be used in the same network and
their ranges overlap it is necessary to have two different dissector tables.
Existing Decode as dissector table can.subdissector stays as is to prevent a
breaking change. But new dissector tables can.id and can.extended_id get
priority over can.subdissector since they are more specific. Id they get a
match can.subdissector won't be called.
New dissector tables can.id and can.extended_id are accessible in lua scripts
via DissectorTable:add() while can.subdissector unfortunately is not.
For related Discussion see MR !3405
Only CAN protocol is supported. Extra information available in J1939
entries is ignored since the J1939 wireshark dissector works with
raw CAN frames and makes no use of this extra information.
The log format may also encapsulate LIN messages which are not
supported by wireshark and thus are ignored.
The only limitation is that relative timestamp format is not
supported. If a file defines relative format of timestamps, packets
are extracted, but timestamps are omitted, since random access deems
impossible without reparsing the whole file up to the packet of
interest. In order to support relative timestamps we need to parse
the whole file at once on open and either dump into a temporary
PCAP file or keep messages in a private list and provide access
to them on read()/seek_read().
The change also creates a separate header for CAN frame structure
definitions which are used by several file readers (candump and
busmaster for now).
Bug: 15939
Change-Id: I87c5555e4e5e1b142b9984b24544b2591d494fbc
Reviewed-on: https://code.wireshark.org/review/34083
Petri-Dish: Anders Broman <a.broman58@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>
João Valverde