Class UsmTimeTable

java.lang.Object
org.snmp4j.security.UsmTimeTable
All Implemented Interfaces:
Serializable
public class UsmTimeTable extends Object implements Serializable
The UsmTimeTable class stores USM user information as part of the Local Configuration Datastore (LCD).
Version:
1.2
Author:
Frank Fock
See Also:

  • Field Details

    • USM_MAX_TIME_DIFFERENCE_HUNDREDS

      public static final int USM_MAX_TIME_DIFFERENCE_HUNDREDS
      See Also:

  • Constructor Details

    • UsmTimeTable

      public UsmTimeTable(OctetString localEngineID, int engineBoots)

  • Method Details

    • addEntry

      public void addEntry(UsmTimeEntry entry)

    • getEntry

      public UsmTimeEntry getEntry(OctetString engineID)

    • getLocalTime

      public UsmTimeEntry getLocalTime()

    • setLocalTime

      public void setLocalTime(UsmTimeEntry localTime)

    • setEngineBoots

      public void setEngineBoots(int engineBoots)
      Sets the number of engine boots.
      Parameters:
      engineBoots - the number of engine boots.
      Since:
      1.2

    • getEngineTime

      public int getEngineTime()
      Returns the number of seconds since the value of the engineBoots object last changed. When incrementing this object's value would cause it to exceed its maximum, engineBoots is incremented as if a re-initialization had occurred, and this object's value consequently reverts to zero.
      Returns:
      a positive integer value denoting the number of seconds since the engineBoots value has been changed.
      Since:
      1.2

    • getEngineBoots

      public int getEngineBoots()
      The number of times that the SNMP engine has (re-)initialized itself since snmpEngineID was last configured.
      Returns:
      the number of SNMP engine reboots.

    • getTime

      public UsmTimeEntry getTime(OctetString engineID)

    • removeEntry

      public void removeEntry(OctetString engineID)
      Removes the specified engine ID from the time cache.
      Parameters:
      engineID - the engine ID of the remote SNMP engine to remove from this time cache.

    • getMaxDiscoveredEntries

      public int getMaxDiscoveredEntries()
      Gets the maximum number of entries created by engine discovery that are kept in this table.

      checkEngineID(OctetString, boolean, int, int) is the only writer of this table that is reached before a received message has been authenticated, so without a limit any peer could grow this table without bound by sending unauthenticated messages with an ever changing authoritative engine ID.

      Returns:
      the maximum number of discovered entries, or 0 if their number is not limited. The default is SNMP4JSettings.getMaxEngineIdCacheSize() at the time this table has been created.
      Since:
      3.13.0

    • setMaxDiscoveredEntries

      public void setMaxDiscoveredEntries(int maxDiscoveredEntries)
      Sets the maximum number of entries created by engine discovery that are kept in this table. Entries added with addEntry(UsmTimeEntry) - for example for a target this entity sends a request to - and entries that have been synchronized by an authenticated message are neither counted nor evicted, so that unauthenticated traffic cannot displace them.
      Parameters:
      maxDiscoveredEntries - the maximum number of discovered entries, or 0 to not limit their number.
      Since:
      3.13.0

    • checkEngineID

      public int checkEngineID(OctetString engineID, boolean discoveryAllowed, int engineBoots, int engineTime)

    • checkTime

      public int checkTime(UsmTimeEntry entry)
      Checks the time window of a received message as defined by RFC 3414 §3.2.7 and updates the time synchronization information of the sending engine accordingly.

      This method must only be called for messages whose authentication digest has been verified. RFC 3414 §3.2.7 is scoped to authenticated messages, and this method marks the time entry of the sending engine as synchronized, which protects it from being evicted as a discovery placeholder.

      Parameters:
      entry - the engine ID, engine boots, and engine time received with the authenticated message.
      Returns:
      SnmpConstants.SNMPv3_USM_OK if the message is inside the time window, SnmpConstants.SNMPv3_USM_NOT_IN_TIME_WINDOW if it is not, and SnmpConstants.SNMPv3_USM_UNKNOWN_ENGINEID if the engine ID is not known.

    • reset

      public void reset()