waitDPIpacket()--Wait for a DPI Packet

 #include <qtossapi.h>

 int   waitDPIpacket(
         long int            timeout,
         void                *dpimsgbuff_p,   
         unsigned long int   *length );

The waitDPIpacket() function waits for a message on the data queue with which the subagent has previously connected (see connectSNMP()--Establish Connection with SNMP Agent). When a Distributed Protocol Interface (DPI) packet arrives, this function receives the packet and copies it to a subagent buffer.

Authorities

So that the subagent can receive messages from the SNMP agent, the following conditions must be met:

• The SNMP agent job must have write access to the data queue. If you suspect a problem with the data queue, check the job log of the SNMP agent job (QTMSNMP in subsystem QSYSWRK) for TCP4041 messages with reason code 001.

Parameters

timeout

(Input) The number of seconds that the subagent is willing to wait for a message (a call to this function will block the subagent until a message is received or until this timeout is reached).

Possible values have the indicated meaning;

< 0	Unlimited wait
0	No wait. This causes an immediate return if a data queue message is not present.
> 0	The number of seconds to wait (maximum is 99999).

dpimsgbuff_p

(I/O) A pointer to a buffer that is owned by the subagent. This will contain the serialized packet from the SNMP agent when snmpsa_RC_ok is returned. The maximum length of a DPI packet is SNMP_DPI_BUFSIZE, defined in the <qtossapi.h> file. The buffer will contain the data queue message itself if that message is not from the SNMP agent, and waitDPIpacket() will return snmpsa_RC_nonagentmsg.

length

(Output) When snmpsa_RC_ok is returned, the length (in bytes) of the DPI packet received. When snmpsa_RC_nonagentmsg is returned, the length of the data queue message. Otherwise, this value is 0.

Return Value

The return values are defined in the <qtossapi.h> file.

For more information, see "SNMP Subagent Problem Determination" in the Simple Network Management Protocol book.

Usage Notes

The waitDPIpacket() function waits for a message on the data queue that the subagent specified on the connectSNMP() call. When a data queue message is received, the corresponding DPI packet is copied to the specified subagent buffer.

If a data queue message arrives that is not from the SNMP agent, then it is returned in the buffer and the code snmpsa_RC_nonagentmsg is returned.

Related Information

• The <qtossapi.h> file (see Header Files for UNIX-Type Functions)
  
  
• connectSNMP()--Establish Connection with SNMP Agent
  
  
• pDPIpacket()--Parse a DPI Packet

Example

See Code disclaimer information for information pertaining to code examples.

  #include <qtossapi.h>
  #define             MAX_LEN       4096
  #define             waitTIMEOUT   300
  unsigned char       *pack_p,
                       dpimsgbuff[MAX_LEN];
  snmp_dpi_hdr        *hdr_p;
  snmp_dpi_set_packet *set_p;
  long int             num, length;

  for(;;) {

     rc = waitDPIpacket( waitTIMEOUT,
                         &dpimsgbuff[0], length );

     if (rc<0) {
         /* Handle exceptions. */
         }

     else {
        hdr_p = pDPIpacket(pack_p);     /* Parse incoming packet. */
                                        /* Assume it's in pack_p. */
        if (hdr_p) {
           /* Analyze packet, assume GET, no error. */
           set_p = mkDPIset(snmp_dpi_set_packet_NULL_p,
                            "1.3.6.1.2.3.4.5.", "1.0",
                            SNMP_TYPE_Integer32,
                            sizeof(num), &num);
           if (set_p) {
              pack_p = mkDPIresponse(hdr_p,
                            SNMP_ERROR_noError, 0L, set_p);
              if (pack_p) {
                 /* Send packet to subagent. */

              } /*end if*/
           } /*end if*/
        } /*end if*/
     } /*end else*/
  } /*end for*/