added pyasn1 decoder failures diagnistics in debug mode

4 files changed, 10 insertions, 5 deletions

diff --git a/CHANGES b/CHANGES
index 11252e3..40f6917 100644
--- a/CHANGES
+++ b/CHANGES
@@ -26,6 +26,7 @@ Revision 4.2.2
 - When running on Python3, SMI will re-raise exceptions with the original
   traceback for easier diagnostics.
 - Out of PYTHONPATH MIB paths now supported.
+- Added pyasn1 decoder failures diagnistics in debug mode.
 - Fix to non-MT-safe class attributes at SNMPv3 MP & SEC modules.
 - Fix to ContextName handling in bytes form whilst running Python3. Data
   mismatch error would return otherwise.
diff --git a/pysnmp/proto/mpmod/rfc2576.py b/pysnmp/proto/mpmod/rfc2576.py
index 2498d6a..6e74f27 100644
--- a/pysnmp/proto/mpmod/rfc2576.py
+++ b/pysnmp/proto/mpmod/rfc2576.py
@@ -1,4 +1,5 @@
 # SNMP v1 & v2c message processing models implementation
+import sys
 from pyasn1.codec.ber import decoder
 from pyasn1.type import univ
 from pyasn1.compat.octets import null
@@ -223,6 +224,7 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
                 wholeMsg, asn1Spec=self._snmpMsgSpec
                 )
         except PyAsn1Error:
+            debug.logger & debug.flagMP and debug.logger('prepareDataElements: %s' % (sys.exc_info()[1],))
             snmpInASNParseErrs, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB', 'snmpInASNParseErrs')
             snmpInASNParseErrs.syntax = snmpInASNParseErrs.syntax + 1
             raise error.StatusInformation(
diff --git a/pysnmp/proto/mpmod/rfc3412.py b/pysnmp/proto/mpmod/rfc3412.py
index aa90caa..e51eb21 100644
--- a/pysnmp/proto/mpmod/rfc3412.py
+++ b/pysnmp/proto/mpmod/rfc3412.py
@@ -459,6 +459,7 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
                 wholeMsg, asn1Spec=self._snmpMsgSpec
                 )
         except PyAsn1Error:
+            debug.logger & debug.flagMP and debug.logger('prepareDataElements: %s' % (sys.exc_info()[1],))
             snmpInASNParseErrs, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB', 'snmpInASNParseErrs')
             snmpInASNParseErrs.syntax = snmpInASNParseErrs.syntax + 1
             raise error.StatusInformation(
diff --git a/pysnmp/proto/secmod/rfc3414/service.py b/pysnmp/proto/secmod/rfc3414/service.py
index 586f6a3..375b90c 100644
--- a/pysnmp/proto/secmod/rfc3414/service.py
+++ b/pysnmp/proto/secmod/rfc3414/service.py
@@ -490,11 +490,12 @@ class SnmpUSMSecurityModel(AbstractSecurityModel):
                 asn1Spec=self.__securityParametersSpec
                 )
         except PyAsn1Error:
-           snmpInASNParseErrs, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB', 'snmpInASNParseErrs')
-           snmpInASNParseErrs.syntax = snmpInASNParseErrs.syntax + 1
-           raise error.StatusInformation(
-               errorIndication=errind.parseError
-               )
+            debug.logger & debug.flagSM and debug.logger('processIncomingMsg: %s' % (sys.exc_info()[1],))
+            snmpInASNParseErrs, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB', 'snmpInASNParseErrs')
+            snmpInASNParseErrs.syntax = snmpInASNParseErrs.syntax + 1
+            raise error.StatusInformation(
+                errorIndication=errind.parseError
+                )
 
         debug.logger & debug.flagSM and debug.logger('processIncomingMsg: %s' % (securityParameters.prettyPrint(),))