modbus: duplicate alerts / detection unaware of direction
In the current master a rule like this
alert modbus any any -> any any (msg:"Start electric motor"; modbus: access write holding, address 521, value 2; sid:6; rev:1; )
Will match both on the toserver and toclient direction regardless of which direction this command was send in. This is because the detection logic is unaware of direction.
Maybe related to #1574.