Abnormal configuration of DNP3 Master causes an infinite loop when outstation has an event buffer overflow

[scaryPonens]

In a testing environment we discovered that when our outstation entered into an "event buffer overflow" state and we set up a dnp3 master with:

• integrity class 0 poll on startup set to "true"
• integrity class 1/2/3 poll on startup set to "false"
• auto integrity scan is "true" when IIN buffer is overflow is observed

The master will enter an infinite loop and not execute any other tasks, e.g. class polls with classes 1, 2, 3 set to "true" to remedy the situation. It is thought that this because the IIN overflow flag in the response to the initial class 0 request triggers an integrity poll, but that's configured to not read class 1+ data.

[emgre]

This is a misconfiguration error. If integrityOnEventOverflowIIN is set, you should make sure that the startupIntegrityClassMask will scan the appropriate events.