netlink: let subdissectors handle the netlink header

Let subdissectors handle parsing and addition of the Netlink header
instead of doing this before calling subdissectors. After this patch:

 - Protocol filters like "netlink-netfilter" can be used to match
   packets (previously only a text item was added to the tree).
 - Subdissectors have more freedom in modifying the type field, so now
   it shows the correct type directly rather than "Message type:
   Protocol-specific".
 - netfilter: the type fields are now actually linked to a tvb,
   previously it was linked to a NULL tvb.
 - netfilter: fix unintended rejection of packets (the length should
   have been added to the offset, otherwise it would fallback to the
   data dissector).
 - Now subdissectors will not be called for control messages (so the
   netlink-conntrack.pcap sample now shows "Netlink" instead of "Netlink
   route" for the "End of dump" control message).

Change-Id: I2ab1bef91fb0080664195b281a6a45c9702914e5
Reviewed-on: https://code.wireshark.org/review/20910
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Michael Mann <mmann78@netscape.net>

0 files changed, 0 insertions, 0 deletions