Fix for an infinite loop in processing ESP, IPv6 packets.
Fix for an infinite loop in processing ESP, IPv6 packets.

The control input routine passes a NULL as its void argument when it
has reached the innermost header, which terminates the loop.

Reported by: Pawel Worach <pawel.worach@gmail.com>
Approved by: re

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase