[AGENT++] subagent mib register with context and net-snmp does not work?

[Claus Klein]

Hi Frank,

I was confused by my  own workaround in net-snmp to ignore the wrong  
set flags.

I found the function witch set the flags and added the switch block to  
check the flags.
The initialisation of int f = flags; was the most important fault  
because the
AGENTX_NON_DEFAULT_CONTEXT bit was set in flags.

With that fix it works fine too with the original net-snmp V5.5.

Can you explain why the flags are not zero at the time of call of  
encode_header()?

With regards,

Claus

#################################################################

void AgentXPdu::encode_header(AgentXOctets& header, int length) const
{
     int f = 0;  // FIXME: not used to init: flags; XXX ck
     /*
      * An optional context field may be present in the agentx- 
Register-,
      * UnRegister-, AddAgentCaps-, RemoveAgentCaps-, Get-, GetNext-,
      * GetBulk-, IndexAllocate-, IndexDeallocate-, Notify-, TestSet-,
      * and Ping- PDUs.
      *
      * The other PDU types don't include context information (RFC  
2741, p. 20).
      */
     switch (ax_type) {
         case AGENTX_OPEN_PDU:
         case AGENTX_CLOSE_PDU:
         case AGENTX_RESPONSE_PDU:
         case AGENTX_COMMITSET_PDU:
         case AGENTX_UNDOSET_PDU:
         case AGENTX_CLEANUPSET_PDU:
             //assert(!(flags & AGENTX_NON_DEFAULT_CONTEXT));  // 
FIXME! it was set before? ck
             //flags &= ~(AGENTX_NON_DEFAULT_CONTEXT); // TBD force to  
clear this bit! ck
             break;
         default:
             if (context.len()>0){
                 f |= AGENTX_NON_DEFAULT_CONTEXT;
             }
             break;
     }
     f |= ((ax_type == AGENTX_REGISTER_PDU) &&
           (region.is_single())) ? AGENTX_INSTANCE_REGISTRATION : 0;
     f |= (network_byte_order()>0) ? AGENTX_NETWORK_BYTE_ORDER : 0;

     header += version;
     header += ax_type;
     header += f;
     header.add_null_octets(1);

     header.encode_int(session_id, network_byte_order());
     header.encode_int(get_transaction_id(), network_byte_order());
     header.encode_int(packet_id, network_byte_order());
     header.encode_int(length, network_byte_order());
}

# ---------------------------------------------------------------------

20100810.12:46:45: 11388: (2)EVENT  : SubAgentXMib: GET (tid)(pid) 
(oid)...: (478), (479), (1.3.6.1.4.1.4976.6.1.2.1)
20100810.12:46:45: 11388: (3)EVENT  : Mib: process subrequest: get  
request, context, oid: (subagent), (478), (1.3.6.1.4.1.4976.6.1.2.1)
20100810.12:46:45: 11388: (3)EVENT  : RequestList: finished subrequest  
(ind)(oid)(val)(syn): (0), (1.3.6.1.4.1.4976.6.1.2.1), (1), (2)
Assertion failed: !(flags & AGENTX_NON_DEFAULT_CONTEXT), file ..\..\.. 
\agentX++\src\agentx_pdu.cpp, line 813

# ---------------------------------------------------------------------

20100810.12:56:53: 892: (2)EVENT  : SubAgent: starting thread execution
20100810.12:56:53: 892: (2)EVENT  : SubAgentXMib: GETBULK (tid)(pid):  
(0), (0)
20100810.12:56:53: 892: (2)EVENT  : Mib: process request: getbulk  
request, oid: (0), (1.3.6.1.4.1.4976.6)
20100810.12:56:53: 892: (3)EVENT  : RequestList: finished subrequest  
(ind)(oid)(val)(syn): (0), (1.3.6.1.4.1.4976.6.1.1.2.71), (2), (2)
20100810.12:56:53: 892: (3)EVENT  : RequestList: finished subrequest  
(ind)(oid)(val)(syn): (1), (1.3.6.1.4.1.4976.6.1.1.2.224), (1), (2)
20100810.12:56:53: 892: (3)EVENT  : RequestList: finished subrequest  
(ind)(oid)(val)(syn): (2), (1.3.6.1.4.1.4976.6.1.1.3.71), (another  
text), (4)
20100810.12:56:53: 892: (3)EVENT  : RequestList: finished subrequest  
(ind)(oid)(val)(syn): (3), (1.3.6.1.4.1.4976.6.1.1.3.224), (a text), (4)
20100810.12:56:53: 892: (3)EVENT  : RequestList: finished subrequest  
(ind)(oid)(val)(syn): (4), (1.3.6.1.4.1.4976.6.1.2.0), (0), (2)
20100810.12:56:53: 892: (3)EVENT  : RequestList: finished subrequest  
(ind)(oid)(val)(syn): (5), (1.3.6.1.4.1.4976.6.1.2.1), (1), (2)
20100810.12:56:53: 892: (3)EVENT  : RequestList: finished subrequest  
(ind)(oid)(val)(syn): (6), (1.3.6.1.4.1.4976.6.1.2.2), (2), (2)
20100810.12:56:53: 892: (3)EVENT  : RequestList: finished subrequest  
(ind)(oid)(val)(syn): (7), (1.3.6.1.4.1.4976.6.1.2.3), (3), (2)
20100810.12:56:53: 892: (3)EVENT  : RequestList: finished subrequest  
(ind)(oid)(val)(syn): (8), (1.3.6.1.4.1.4976.6.1.2.4), (4), (2)
20100810.12:56:53: 892: (3)EVENT  : RequestList: finished subrequest  
(ind)(oid)(val)(syn): (9), (1.3.6.1.4.1.4976.6.1.2.5), (5), (2)
Assertion failed: !(flags & AGENTX_NON_DEFAULT_CONTEXT), file ..\..\.. 
\agentX++\src\agentx_pdu.cpp, line 813


On 08.08.2010, at 23:08, Claus Klein wrote:

> Hi Frank,
>
> you are right, it is a net-snmp problem.
>
> AgentX++ send the right response message, but net-snmp set the flag
> itself and expect the context, I do not know why?
>
> Thanks for help!
>
> With regards,
>
> Claus
>
> On 06.08.2010, at 22:39, Claus Klein wrote:
>
>> Hi Frank,
>>
>> for me it is a AgentX++ problem.
>> Did you receive my log file?
>>
>> The subagent AgentX Response is wrong coded in case of a get request
>> with context:
>>
>> There is an invalid nonDefaultContext flag set, what is not allowed!
>> And the context is empty too or the rest fields?
>
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