attempt to use process elapsed time (whenever available) for

timestamping timeframe, as elapsed time may not be affected by
system clock reset.

1 files changed, 13 insertions, 5 deletions

diff --git a/pysnmp/proto/secmod/rfc3414/service.py b/pysnmp/proto/secmod/rfc3414/service.py
index d9e01fc0..3392dce4 100644
--- a/pysnmp/proto/secmod/rfc3414/service.py
+++ b/pysnmp/proto/secmod/rfc3414/service.py
@@ -9,8 +9,16 @@ from pyasn1.type import univ, namedtype, constraint
 from pyasn1.codec.ber import encoder, decoder
 from pyasn1.error import PyAsn1Error
 from pysnmp import debug
-import time
-
+import os
+
+if os.times()[-1]: # this is not affected by system clock reset
+    def _getTimestamp():
+        return abs(int(os.times()[-1]))
+else:
+    import time
+    def _getTimestamp():
+        return int(time.time())
+    
 # USM security params
 
 class UsmSecurityParameters(rfc1155.TypeCoercionHackMixIn, univ.Sequence):
@@ -491,7 +499,7 @@ class SnmpUSMSecurityModel(AbstractSecurityModel):
                     securityParameters.getComponentByPosition(1),
                     securityParameters.getComponentByPosition(2),
                     securityParameters.getComponentByPosition(2),
-                    int(time.time())
+                    _getTimestamp()
                     )
                 
                 expireAt = self.__expirationTimer + 300
@@ -648,7 +656,7 @@ class SnmpUSMSecurityModel(AbstractSecurityModel):
                         msgAuthoritativeEngineID
                         ]
                     # time passed since last talk with this SNMP engine
-                    idleTime = int(time.time())-latestUpdateTimestamp
+                    idleTime = abs(_getTimestamp()-latestUpdateTimestamp)
                     debug.logger & debug.flagSM and debug.logger('processIncomingMsg: read timeline snmpEngineBoots %s snmpEngineTime %s for msgAuthoritativeEngineID %s, idle time %s secs' % (snmpEngineBoots, snmpEngineTime, msgAuthoritativeEngineID, idleTime))
                 else:
                     raise error.ProtocolError('Peer SNMP engine info missing')
@@ -684,7 +692,7 @@ class SnmpUSMSecurityModel(AbstractSecurityModel):
                         msgAuthoritativeEngineBoots,
                         msgAuthoritativeEngineTime,
                         msgAuthoritativeEngineTime,
-                        int(time.time())
+                        _getTimestamp()
                         )
                     debug.logger & debug.flagSM and debug.logger('processIncomingMsg: stored timeline msgAuthoritativeEngineBoots %s msgAuthoritativeEngineTime %s for msgAuthoritativeEngineID %s' % (msgAuthoritativeEngineBoots, msgAuthoritativeEngineTime, msgAuthoritativeEngineID))