rfc3412.txt

开发snmp的开发包有两个开放的SNMP开发库

      Dispatching for Incoming Messages.

4.2.2.  PDU Dispatching for Incoming Messages

   The elements of procedure for the dispatching of PDUs depends on the
   value of sendPduHandle.  If the value of sendPduHandle is <none>,
   then this is a request or notification and the procedures specified
   in Section 4.2.2.1 apply.  If the value of snmpPduHandle is not
   <none>, then this is a response and the procedures specified in
   Section 4.2.2.2 apply.







Case, et al.                Standards Track                    [Page 12]

RFC 3412      Message Processing and Dispatching for SNMP  December 2002


4.2.2.1.  Incoming Requests and Notifications

   The following procedures are followed for the dispatching of PDUs
   when the value of sendPduHandle is <none>, indicating this is a
   request or notification.

   1) The combination of contextEngineID and pduType is used to
      determine which application has registered for this request or
      notification.

   2) If no application has registered for the combination, then:

      a) The snmpUnknownPDUHandlers counter is incremented.

      b) A Response message is generated using the abstract service
         primitive:

         result =                       -- SUCCESS or FAILURE
         prepareResponseMessage(
         IN   messageProcessingModel    -- as provided by MP module
         IN   securityModel             -- as provided by MP module
         IN   securityName              -- as provided by MP module
         IN   securityLevel             -- as provided by MP module
         IN   contextEngineID           -- as provided by MP module
         IN   contextName               -- as provided by MP module
         IN   pduVersion                -- as provided by MP module
         IN   PDU                       -- as provided by MP module
         IN   maxSizeResponseScopedPDU  -- as provided by MP module
         IN   stateReference            -- as provided by MP module
         IN   statusInformation         -- errorIndication plus
                                        -- snmpUnknownPDUHandlers OID
                                        -- value pair.
         OUT  destTransportDomain       -- destination transportDomain
         OUT  destTransportAddress      -- destination transportAddress
         OUT  outgoingMessage           -- the message to send
         OUT  outgoingMessageLength     -- its length
         )

      c) If the result is SUCCESS, then the prepared message is sent to
         the originator of the request as identified by the
         transportDomain and transportAddress.  The transport used to
         send the outgoingMessage is returned via destTransportDomain,
         and the address to which it was sent is returned via
         destTransportAddress.

      d) The incoming message is discarded without further processing.
         Message Processing for this message is complete.




Case, et al.                Standards Track                    [Page 13]

RFC 3412      Message Processing and Dispatching for SNMP  December 2002


   3) The PDU is dispatched to the application, using the abstract
      service primitive:

      processPdu(                     -- process Request/Notification
        IN   messageProcessingModel   -- as provided by MP module
        IN   securityModel            -- as provided by MP module
        IN   securityName             -- as provided by MP module
        IN   securityLevel            -- as provided by MP module
        IN   contextEngineID          -- as provided by MP module
        IN   contextName              -- as provided by MP module
        IN   pduVersion               -- as provided by MP module
        IN   PDU                      -- as provided by MP module
        IN   maxSizeResponseScopedPDU -- as provided by MP module
        IN   stateReference           -- as provided by MP module
                                      -- needed when sending response
             )

      Message processing for this message is complete.

4.2.2.2.  Incoming Responses

   The following procedures are followed for the dispatching of PDUs
   when the value of sendPduHandle is not <none>, indicating this is a
   response.

   1) The value of sendPduHandle is used to determine, in an
      implementation-defined manner, which application is waiting for a
      response associated with this sendPduHandle.

   2) If no waiting application is found, the message is discarded
      without further processing, and the stateReference is released.
      The snmpUnknownPDUHandlers counter is incremented.  Message
      Processing is complete for this message.

   3) Any cached information, including stateReference, about the
      message is discarded.















Case, et al.                Standards Track                    [Page 14]

RFC 3412      Message Processing and Dispatching for SNMP  December 2002


   4) The response is dispatched to the application using the abstract
      service primitive:

      processResponsePdu(              -- process Response PDU
        IN   messageProcessingModel    -- provided by the MP module
        IN   securityModel             -- provided by the MP module
        IN   securityName              -- provided by the MP module
        IN   securityLevel             -- provided by the MP module
        IN   contextEngineID           -- provided by the MP module
        IN   contextName               -- provided by the MP module
        IN   pduVersion                -- provided by the MP module
        IN   PDU                       -- provided by the MP module
        IN   statusInformation         -- provided by the MP module
        IN   sendPduHandle             -- provided by the MP module
             )

      Message Processing is complete for this message.

4.3.  Application Registration for Handling PDU types

   Applications that want to process certain PDUs must register with the
   PDU Dispatcher.  Applications specify the combination of
   contextEngineID and pduType(s) for which they want to take
   responsibility.

   1) An application registers according to the abstract interface
      primitive:

      statusInformation =           -- success or errorIndication
        registerContextEngineID(
        IN   contextEngineID        -- take responsibility for this one
        IN   pduType                -- the pduType(s) to be registered
             )

      Note: Implementations may provide a means of requesting
      registration for simultaneous multiple contextEngineID values,
      e.g., all contextEngineID values, and may also provide a means for
      requesting simultaneous registration for multiple values of the
      pduType.

   2) The parameters may be checked for validity; if they are not, then
      an errorIndication (invalidParameter) is returned to the
      application.

   3) Each combination of contextEngineID and pduType can be registered
      only once.  If another application has already registered for the
      specified combination, then an errorIndication (alreadyRegistered)
      is returned to the application.



Case, et al.                Standards Track                    [Page 15]

RFC 3412      Message Processing and Dispatching for SNMP  December 2002


   4) Otherwise, the registration is saved so that SNMP PDUs can be
      dispatched to this application.

4.4.  Application Unregistration for Handling PDU Types

   Applications that no longer want to process certain PDUs must
   unregister with the PDU Dispatcher.

   1) An application unregisters using the abstract service primitive:

      unregisterContextEngineID(
       IN   contextEngineID        -- give up responsibility for this
       IN   pduType                -- the pduType(s) to be unregistered
            )

      Note: Implementations may provide a means for requesting the
      unregistration for simultaneous multiple contextEngineID values,
      e.g., all contextEngineID values, and may also provide a means for
      requesting simultaneous unregistration for multiple values of
      pduType.

   2) If the contextEngineID and pduType combination has been
      registered, then the registration is deleted.

      If no such registration exists, then the request is ignored.

5.  Definitions

5.1.  Definitions for SNMP Message Processing and Dispatching

   SNMP-MPD-MIB DEFINITIONS ::= BEGIN

   IMPORTS
       MODULE-COMPLIANCE, OBJECT-GROUP         FROM SNMPv2-CONF
       MODULE-IDENTITY, OBJECT-TYPE,
       snmpModules, Counter32                  FROM SNMPv2-SMI;

   snmpMPDMIB MODULE-IDENTITY
       LAST-UPDATED "200210140000Z"
       ORGANIZATION "SNMPv3 Working Group"
       CONTACT-INFO "WG-EMail:   [e-mail]
                     Subscribe:  [e-mail]

                     Co-Chair:   Russ Mundy
                                 Network Associates Laboratories
                     postal:     15204 Omega Drive, Suite 300
                                 Rockville, MD 20850-4601
                                 USA



Case, et al.                Standards Track                    [Page 16]

RFC 3412      Message Processing and Dispatching for SNMP  December 2002


                     EMail:      [e-mail]
                     phone:      [phone]

                     Co-Chair &
                     Co-editor:  David Harrington
                                 Enterasys Networks
                     postal:     35 Industrial Way
                                 P. O. Box 5005
                                 Rochester NH 03866-5005
                                 USA
                     EMail:      [e-mail]
                     phone:      [phone]

                     Co-editor:  Jeffrey Case
                                 SNMP Research, Inc.
                     postal:     3001 Kimberlin Heights Road
                                 Knoxville, TN 37920-9716
                                 USA
                     EMail:      [e-mail]
                     phone:      [phone]

                     Co-editor:  Randy Presuhn
                                 BMC Software, Inc.
                     postal:     2141 North First Street
                                 San Jose, CA 95131
                                 USA
                     EMail:      [e-mail]
                     phone:      [phone]

                     Co-editor:  Bert Wijnen
                                 Lucent Technologies
                     postal:     Schagen 33
                                 3461 GL Linschoten
                                 Netherlands
                     EMail:      [e-mail]
                     phone:      [phone]
                    "
       DESCRIPTION  "The MIB for Message Processing and Dispatching

                     Copyright (C) The Internet Society (2002). This
                     version of this MIB module is part of RFC 3412;
                     see the RFC itself for full legal notices.
                    "
       REVISION     "200210140000Z"            -- 14 October 2002
       DESCRIPTION  "Updated addresses, published as RFC 3412."
       REVISION     "199905041636Z"            -- 4 May 1999
       DESCRIPTION  "Updated addresses, published as RFC 2572."




Case, et al.                Standards Track                    [Page 17]

RFC 3412      Message Processing and Dispatching for SNMP  December 2002


       REVISION     "199709300000Z"            -- 30 September 1997
       DESCRIPTION  "Original version, published as RFC 2272."
       ::= { snmpModules 11 }

   -- Administrative assignments ***************************************

   snmpMPDAdmin           OBJECT IDENTIFIER ::= { snmpMPDMIB 1 }
   snmpMPDMIBObjects      OBJECT IDENTIFIER ::= { snmpMPDMIB 2 }
   snmpMPDMIBConformance  OBJECT IDENTIFIER ::= { snmpMPDMIB 3 }

   -- Statistics for SNMP Messages *************************************

   snmpMPDStats           OBJECT IDENTIFIER ::= { snmpMPDMIBObjects 1 }

   snmpUnknownSecurityModels OBJECT-TYPE
       SYNTAX       Counter32
       MAX-ACCESS   read-only
       STATUS       current
       DESCRIPTION "The total number of packets received by the SNMP
                    engine which were dropped because they referenced a
                    securityModel that was not known to or supported by
                    the SNMP engine.
                   "
       ::= { snmpMPDStats 1 }

   snmpInvalidMsgs OBJECT-TYPE