CIP (Common Industrial Protocol) is a protocol used in SCADA networks. The
standard is managed by ODVA (Open DeviceNet Vendor Association). 

The CIP inspector decodes the CIP protocol and provides rule options to 
access certain protocol fields. This allows a user to write rules for CIP 
packets without decoding the protocol with a series of ”content” and ”byte 
test” options.

The inspector only evaluates PAF-flushed PDUs. If the rule options don't
check for this, they'll fire on stale session data when the original packet
goes through before flushing.

