Dialogic 05-2239-009 User Manual

A code example that illustrates the general procedure for retrieving information from all incoming 
messages associated with the SUBSCRIBE and NOTIFY methods is included in 

, on page 225.

Once an application has received a GCEV_EXTENSION event for a SIP SUBSCRIBE request and 
extracted the information from the event, it must send a response message. 

The response is sent as an Extension message, passing a parameter block that contains the 
following element:

IPSET_MSG_SIP

IPPARM_MSGTYPE
and one of the following two parameter values:

IP_MSGTYPE_SIP_SUBSCRIBE_ACCEPT

IP_MSGTYPE_SIP_SUBSCRIBE_REJECT

The “Accept” message is a 200 OK, while the “Reject” message is a 501 response. In either case, 
the response message must include the Call-ID header field value that was received in the 
SUBSCRIBE request so that the subscriber can match the response to the request. 

The following two code snippets illustrate how an application would send “Accept” and “Reject” 
responses to SUBSCRIBE requests.

When accepting a SUBSCRIBE request, a SIP entity normally includes an Expires header field, 
which may contain the same value that was received in the Expires header field of the 
SUBSCRIBE request or any smaller value.

void CSubNotMgr::SendSIPSubscribeAccept (char* pExpire)
{
   char        str[MAX_STRING_SIZE];
   sprintf(str, "<--- Sending SIP SUBSCRIBE Accept\n");
   printandlog(ALL_DEVICES, MISC, NULL, str, 0);

   GC_PARM_BLKP   parmblkp = NULL;   // input parameter block pointer 
   GC_PARM_BLKP   retblkp = NULL;    // return parameter block
   GC_INFO        gc_error_info;     // GlobalCall error information data 
   int            retval = GC_SUCCESS;

   gc_util_insert_parm_val(&parmblkp,
                           IPSET_MSG_SIP,
                           IPPARM_MSGTYPE,
                           sizeof(int),
                           IP_MSGTYPE_SIP_SUBSCRIBE_ACCEPT);

   // Insert SIP Expire field 
   gc_util_insert_parm_ref_ex(&parmblkp,
                              IPSET_SIP_MSGINFO,
                              IPPARM_EXPIRES_HDR,
                              (unsigned long)(strlen(pExpire)),
                              pExpire);