Error: Unhandled Exception (group=1, code=6)?

Question

I am trying to dissect the captured pcap header using libwireshark.so, but when i call

epan_dissect_init(&edt,true,true);
epan_dissect_run();

I see this error:

Error: Unhandled Exception (group=1, code=6)

Why?

Accepted Answer

thanks guys!

there was some problem in initializing the epan

after fixing that now its working :-)

Answer 2

As I said earlier:

" ....you are basically on your own if you are trying to use libwireshark directly. :-)

At the very least you need to be quite comfortable using a debugger to trace through the code to see why you are getting the error."

In this case, something caused an Exception (trap) and there was no code to 'handle' the exception.

I would use a debugger to step through the code following the call to epan_dissect_run() to see where the exception occurs.

You probably don't need to worry too much how exceptions work; You just need to find the place in the code which caused the exception.

Answer 3

It means a dissector failed to allocate memory (see code 6's definition below)...

The exception group value is always 1, and the exception codes are defined here (based on epan/exceptions.h):

Code	Description
1	`BoundsError` Index is out of range. An attempt was made to read past the end of a buffer. This generally means that the capture was done with a "slice" length or "snapshot" length less than the maximum packet size, and a link-layer packet was cut short by that, so not all of the data in the link-layer packet was available.
2	`ReportedBoundsError` Index is beyond reported length (not cap_len). An attempt was made to read past the logical end of a buffer. This differs from a BoundsError in that the parent protocol established a limit past which this dissector should not process in the buffer and that limit was exceeded. This generally means that the packet is invalid, i.e. whatever code constructed the packet and put it on the wire didn't put enough data into it. It is therefore currently reported as a "Malformed packet". However, it also happens in some cases where the packet was fragmented and the fragments weren't reassembled. We need to add another length field to a tvbuff, so that "length of the packet from the link layer" and "length of the packet were it fully reassembled" are different, and going past the first of those without going past the second would throw a different exception, which would be reported as an "Unreassembled packet" rather than a "Malformed packet".
3	`TypeError` During display-filter parsing
4	`DissectorError` A bug was detected in a dissector. DO NOT throw this with `THROW()`; that means that no details about the dissector error will be reported. (Instead, the message will blame you for not providing details.) Instead, use the `DISSECTOR_ASSERT()`, etc. macros in epan/proto.h.
5	`ScsiBoundsError` Index is out of range. An attempt was made to read past the end of a buffer. This error is specific to SCSI data transfers where for some CDBs it is normal that the data PDU might be short. I.e. ReportLuns initially called with allocation_length=8, just enough to get the "size" of lun list back after which the initiator will reissue the command with an allocation_length that is big enough.
6	`OutOfMemoryError` Running out of memory. A dissector tried to allocate memory but that failed.