core: make PacketInfo superclass

All packet info class wrappers must subclass from this class.

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
core: make module reference to packet info visible

Start to wrap() connection and flow id via PacketInfo class.

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
core: add function to get unwinded class instance

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
time-sequence: add zero option

Large TCP sequence number can be hard to read. Often the absolute number
is not required, a delta timestamp, starting with 0 is often superior.
The --zero (-Z) option just provide this information.

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
sequence-container: fix numpy module import

numpy has no second level class support or whatever is intended. Just
import first level instance and things work magically.

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
time-sequence: modify help/usage output

If the user forgot to provide a pcap filename the short description is
outputed. Now - because I think the user has no idea if he specify no
argument the whole usage() is printed too.

This should increase the user experience[TM].

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
core: print error and exit if snaplen is to short.

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
time-sequence: add TCP ACK and SACK offsets

The introduced offset information with zero option was missed for ACK
and SACK (selective ACKs) packets. So we add support here.

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>