snmp-faq-1.1.ascii

官方源码

commands,
other than SIOCGMIB2CNFG and GIOCGMIB2CNTRS, for other MIB-II variables?



RESOLUTION:

SNMP uses UDP and responds to all the queries on a transaction basis. Any
number of SNMP managers can talk to the SNMP agent.

There are three things going on here:

1) The TCP/IP MIB is called the MIB-II, and this is what is shipped by
   VxWorks. This MIB defines information for all the IP interfaces in the 
   systems. Whether they are ethernet, token ring, fddi, ppp, ..etc.  
   Each interface is responsible for providing this information in their IP 
   interface driver with the IOCTL described in the release notes.  
   The interface MIB support is described in MIB-II RFC which is rfc1213.

2) An FDDI driver is more complicated than an ethernet driver.  
   It requires a protocol of its own to maintain ring communications.  
   This protocol is call Station Management (SMT).  This protocol has a MIB of 
   its own and it is defined RFC-1512.  
   Look in target/src/snmpv1/mibs/rfc1512.mib
   This is a MIB which requires new development and is independet of MIB-II.

3) There are SNMP FDDI station variables which defines a MIB, this
   MIB is define in RFC-1285. Again these are FDDI station specific
   parameters and have nothing to do with the IOCTL that is sent from the 
   MIB-II parameter interface definitions.

NOTE - The FDDI MIB is not part of the TCP/IP MIB.  FDDI MIB is independent and
       the user needs to develop the MIB.  The FDDI MIB is defined in the 
       RFC-1285,1512,1558.
       
       At the time of writing this FAQ the BSP Porting Kit is for Tornado 1.0.1
       is not yet published for users. The BSP Port. Kit document should 
       include the details on how to add a custom network interaface driver
       to VxWorks.

SPR / PATCH: 3452

KEYWORDS:

--------------------------------------------------------------------------

5. TITLE: getproc_got_string manpage missing how snmpdMemoryFree is used. 


                         SCOPE                   DISCOVERED ON
              HOST:  All
                     -------------------     -------------------
      ARCHITECTURE:  All
                     -------------------     -------------------
               BSP:  All
                     -------------------     -------------------
PRODUCT / REVISION:  snmpv1/v2c 1.0
                     -------------------     -------------------

DESCRIPTION OF PROBLEM:

In WindNet SNMPv1/v2c Component Release Supplement, SNMP Libraries
Reference, pg 160, getproc_got_string.  The "dynamicFlg" tells the agent
that snmpdMemoryAlloc was used to allocate memory for the data buffer.
It also says that snmpdMemoryFree should be called to free it.  Who calls
snmpdMemoryFree?  If the SNMP designer needs to add this call, where
should he add it? What is meant by "freed later" ?

RESEARCH:

RESOLUTION:

The snmpdMemoryFree is called by the agent when the packet processing
is finished i.e. when the agent has finished generating the response
packet for the request (this is what means by "freed later").
It is not clear from the man page who is calling the free routine and
Note that snmpdMemoryFree is distributed in snmpIoLib.c and the user
can write their own free routine if they do not want to use the one provided 
by WindNet snmp agent.

SPR / PATCH:  8484

KEYWORDS:

--------------------------------------------------------------------------

6. TITLE: The trap processing is missing a reference to the hook for 
          releasing privately allocated memory.


                         SCOPE                   DISCOVERED ON
              HOST:  All
                     -------------------     -------------------
      ARCHITECTURE:  All
                     -------------------     -------------------
               BSP:  All
                     -------------------     -------------------
PRODUCT / REVISION:  snmpv1/v2c 1.0
                     -------------------     -------------------

DESCRIPTION OF PROBLEM:

In WindNet SNMPv1/v2c Component Release Supplement, Section 4.12.8
Trap Processing, pg 42, Figure 4-4.  The diagram shows an optional hook
to release privately-allocated memory.  How do I tell the SNMP Agent
about this Hook and what are the parameters? Reference to this optional
hook is missing in the trap processing section on pg 41.

RESOLUTION:

snmpdInitFinish() and pPrivRlse can be used to release privately
allocated memory. The section 4.10.4 on VarBind Private Field for set
operations talks about private-memory-deallocation hook. The same process
can be used for trap processing also, see pg. 34.

SPR / PATCH: 8485

--------------------------------------------------------------------------

7. TITLE: nextproc_next_instance() does not explain the reference point 
          of the instance.


                         SCOPE                   DISCOVERED ON
              HOST:  All
                     -------------------     -------------------
      ARCHITECTURE:  All
                     -------------------     -------------------
               BSP:  All
                     -------------------     -------------------
PRODUCT / REVISION:  snmpv1/v2c 1.0
                     -------------------     -------------------

DESCRIPTION OF PROBLEM:

In WindNet SNMPv1/v2c Component Release Supplement, SNMP Libraries
Reference, pg 165.  nextproc_next_instance:  What is the reference point
of the instance?  Is it the next instance related to the instance passed
into the getproc procedure, or is it the next instance relating to the
instance found?

RESOLUTION: 

It is instance found.
nextproc_next_instance(pktp, vbp, GroupEntry_INSTANCE_LEN, next_inst);

The instance part described here should be the instance part of the
next value that is retrieved.

SPR / PATCH: 8486

--------------------------------------------------------------------------

8. TITLE: snmpSet() and snmpTest() in snmpSnmp.c have incorrect code. 


                         SCOPE                   DISCOVERED ON
              HOST:  all
                     -------------------     -------------------
      ARCHITECTURE:  all
                     -------------------     -------------------
               BSP:  all
                     -------------------     -------------------
PRODUCT / REVISION:  snmpv1/v2c 1.0 FCS
                     -------------------     -------------------

DESCRIPTION OF PROBLEM: 

Unable to SET the MIB variable snmpEnableAuthenTraps from the SNMP manager.
The following problem is in snmpSnmp.c
In function snmpSet() setproc_good() is missing.
In function snmpTest() the logical operator is incorrect.

RESEARCH:

RESOLUTION:
In snmpSet() the code should be ...

    {
    snmp_stats.snmpEnableAuthTraps = vbp->value_u.v_number;
    setproc_good(pktp, vbp);
    return;
    }

In snmpSet() the code should be ...

    /* Check for the only 2 permissible values */

    if ((vbp->value_u.v_number != VAL_snmpEnableAuthenTraps_enabled) &&
        (vbp->value_u.v_number != VAL_snmpEnableAuthenTraps_disabled))
       {
       testproc_error (pktp, vbp, WRONG_VALUE);
       return;
       }


SPR / PATCH: 8490, 8491

KEYWORDS:

--------------------------------------------------------------------------

9. TITLE: SNMPv1/v2c 1.0 demo MIB exmaple from the user guide does 
          not compile.

                         SCOPE                   DISCOVERED ON
              HOST:  All
                     -------------------     -------------------
      ARCHITECTURE:  All
                     -------------------     -------------------
               BSP:  All
                     -------------------     -------------------
PRODUCT / REVISION:  SNMPv1/v2c 1.0          Tornado 1.0
                     -------------------     -------------------

DESCRIPTION OF PROBLEM: 

The SNMP demo MIB example 6-4 (augmented demo.c with
method routines) does not build when executing step 5.
Example 6-1 demo.mib that is on the WEB (Windsurf)
does not compile using mibcomp.

RESOLUTION: A patch is available in support
            Patched Modules - demo.mib and demo.c

            The makefile in this patch can be used as a reference to modify
            the Makefile that is in your agent dirctory. Follow
            the instructions in Step 5 (pg 67) on how to build the snmp
            the instructions in Step 5 (pg 67) on how to build the snmp
            agent with the demo.c(method routines). And execute Step 6
            to integrate the agent into vxworks.

The following files should be distributed with this patch -
demo.mib, demo.c, Makefile

SPR / PATCH: 8373 / 5.3FCS-spr8373-snmpv1v2c-demo-mib
--------------------------------------------------------------------------

10. TITLE: snmpGroupedVbsProcess() prototype defined in snmpdLib.h is 
           not found.


                         SCOPE                   DISCOVERED ON
              HOST:  All
                     -------------------     -------------------
      ARCHITECTURE:  All
                     -------------------     -------------------
               BSP:  All
                     -------------------     -------------------
PRODUCT / REVISION:  snmpv1/v2c 1.0
                     -------------------     -------------------

DESCRIPTION OF PROBLEM:

In snmpdLib.h file the following prototype exists but it cannot be found
in the snmp manual or vxworks image:     

extern void     snmpGroupedVbsProcess (SNMP_PKT_T *, VB_T *, VOIDFUNCPTR, int);

RESOLUTION:

This is not a user function, this was used internally and it does
not exist in the current product.

SPR / PATCH: 8388

KEYWORDS:

--------------------------------------------------------------------------

11. TITLE: Prototype for snmpdContinue() is missing in snmpdLib.h.


                         SCOPE                   DISCOVERED ON
              HOST:  All
                     -------------------     -------------------
      ARCHITECTURE:  All
                     -------------------     -------------------
               BSP:  All
                     -------------------     -------------------
PRODUCT / REVISION:  snmpv1/v2c 1.0
                     -------------------     -------------------

DESCRIPTION OF PROBLEM:

Prototype for snmpdContinue is missing in snmpdLib.h and compiler warnings
are generated. 


RESOLUTION:

A valid header file with the prototype is needed. 

SPR / PATCH: 8041

KEYWORDS:

--------------------------------------------------------------------------

12. TITLE: What can I do to make the -stub option generate method 
           routines for the SNMP trap objects.


                         SCOPE                   DISCOVERED ON
              HOST:  All
                     -------------------     -------------------
      ARCHITECTURE:  All
                     -------------------     -------------------
               BSP:  All
                     -------------------     -------------------
PRODUCT / REVISION:  snmpv1/v2c 1.0
                     -------------------     -------------------

DESCRIPTION OF PROBLEM:

We have a MIB, and by using -stub, method routines are generated for
Objects, Table Objects, but not for TRAP ?
What can I do to make it generate meothod routines for TRAP object ?

RESOLUTION:

The snmpv1/v2c 1.0 MIB compiler does not support the trap flag option so the 
trap stub routines will not be created. However there is request for
enhacement to provide this option. 

SPR / PATCH: 8227

KEYWORDS:

--------------------------------------------------------------------------

13. TITLE: When to use non-asynch functions, %n or %N option.  


                         SCOPE                   DISCOVERED ON
              HOST:  All
                     -------------------     -------------------
      ARCHITECTURE:  All
                     -------------------     -------------------
               BSP:  All
                     -------------------     -------------------
PRODUCT / REVISION:  snmpv1/v2c 1.0
                     -------------------     -------------------

DESCRIPTION OF PROBLEM:

snmpMib2.mib DEFAULTs are always 'asynch' and for the parent (%p) node.
When would you use the non-asynch functions?  When would you use the %n or 
%N option?  Does it depend whether the variable is scalar or a tabular leaf ?
I've been using the defaults from snmpMib2.mib.


RESOLUTION:

Currently all method routines are synchronous. Synchronous functions
can be used when you want sequential execution. For example if you have a
GET process for OID 1.4.0 and 1.5.0, The method routine for 1.5.0 will not
get invoked until method for 1.4.0 is done. 

If you have asynchronous method routine for 1.4.0, it can return to the 
main thread, and the task that was started off by this routine will go 
about doing the necessary work for the response packet; While this is being 
done you can have method routine for 1.5.0 invoked and not wait for 1.4.0 
to finish.  The async version of the functions holds good for async 
and non-async routines, so use async suffix.

The difference beteween %n and %N is described in appendix A. of the WindNet
SNMPv1/v2c Component Release Supplement 1.0 Edition 1

You can use this for scalar or table variable.