Wireshark is distributed under the GNU GPL version 2. There are no
restrictions on its use. There are significant restrictions on its
distribution.

Parts of Wireshark can be built and distributed as libraries. These
parts are still covered by the GPL, and NOT by the Lesser General Public
License or any other license.

If you create a combined work using all or part of Wireshark, then your
combined work must be released under a license compatible with the GPL.

...and don't get us started on trademarks.

The full text of the GNU GPL may be viewed in
/usr/share/common-licenses/GPL-2.