DAG transmit output does not align records correctly or support extension headers

antcodd commented 6 years ago

DAG transmit in format_dag25 is somewhat broken:

Records should be aligned to 64-bit with 0 padding or they will not transmit on physical cards. If the record is snapped it should be rounded down to the next lowest 8 byte boundary. Libtrace format_erf currently always strips padding when writing to ERF which effectively means no ERF file created by libtrace is transmittable by libtrace DAG.
Extension headers are not copied correctly.
The write functions of format_dag25 and format_erf should probably be unified.

l4dri4l commented 5 years ago

+1, when using erf:out.erf, the DAG cards does not transmit the traces, due to the misalignment. Any idea on how to simply fix it?

salcock commented 5 years ago

There is a PR with a proposed fix here -- I've had a chance to test it out properly yet but you could try patching that change in and see if it works for you?

l4dri4l commented 5 years ago

Hi salcock ! Thanks for your reply ! I patched the lib this morning, still doesn't work, but what bugs me is that it doesn't even work on properly aligned erf files... I'll continue to look into it and keep you advised

LibtraceTeam / libtrace

DAG transmit output does not align records correctly or support extension headers #62