On Tue, 21 Sep 2004 17:19:54 -0700 Jeff wrote:
JJ> Back in April, Martin Carlsson of Lumentis observed in the thread
JJ> entitled "engineTime and abrupt timechanges" that changes to the system
JJ> time could prevent the agent from authenticating snmpv3 messages
JJ> (reference
JJ> http://sourceforge.net/mailarchive/message.php?msg_id=8116151).  In a
JJ> subsequent message he proposes a patch which uses ticks since reboot via
JJ> 'times()' instead of wall clock as the basis of the engineTime.  In June
JJ> in a different thread entitled "usmStatsNotInTimeWindows issues" Thomas
JJ> Anders showed an additional problem with the current engineTime
JJ> mechanism such that after an uptime of 248 days the engineTime
JJ> calculation overflows, also causing problems.

I believe Wes is going to look into these issues before 5.2 goes out.


JJ> The reason I'm writing is that since then, I've been looking at other
JJ> portions of the net-snmp code which could also suffer when there are
JJ> abrupt changes in the system time.  Some of these are minor, such as
JJ> sysORTable code producing strange timestamps.  Others are potentially
JJ> very bad, including all of the table cache support.
JJ> 
JJ> Would it make sense to revisit all of the code which currently uses
JJ> system time and rewrite it to use a timebase that won't change when NTP
JJ> or other mechanism are used to modify the system clock?  Perhaps a
JJ> generic timestamp library?

That sounds like a reasonable idea. From you review of the code, does it look
like it wouldn't be too difficult to do?

-- 
Robert Story; NET-SNMP Junkie <http://www.net-snmp.org/>
<irc://irc.freenode.net/#net-snmp>
Archive: <http://sourceforge.net/mailarchive/forum.php?forum=net-snmp-coders>

You are lost in a twisty maze of little standards, all different. 


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