create new return state + consolidate state values
Create new error exit status. The status should indicate that the plug-in crashed due to some non-DANE and non-DNSSEC related fault.
I also propose renaming and changing the values of return states. Return states should be divided into three groups. These groups should be easily identifiable by their prefixes.
Suggested prefixes (change asterisk to DANE or DNSSEC):
*SUCESS: Validation was successful. All required data were acquired and validation was successful. These states should hold the values of small positive integers.
*FAILURE: Validation was not successful. All required data were acquired but validation failed. This may be caused by invalid data. These states should consist of large positive integers.
*ERROR: Validation was not successful. Some data couldn't be acquired due to some communication or system error.
Use DANE_ERROR_GENERIC and DNSSEC_ERROR_GENERIC for an generic error (e.g., allocation or socket creation failed).