Verbs API

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An AIX® application can determine the verbs API that is either the Open Fabrics Enterprise Distribution (OFED) verbs or the AIX InfiniBand (IB) verbs that must communicate with a specific destination.

The following example in pseudocode tests the result of the rdma_resolve_addr command on the required remote address to determine the OFED verbs that can be used.

The program returns the following values:
  • 0- if the communication with the destination can be established by using the OFED verbs.
  • error- if the communication with the destination cannot be established through an OFED supported device, but communication can be established by using the InfiniBand architecture.
/*The following check_ofed_verbs_support routine does:
/*- Call rdma_create_event_channel	to open a channel event	    */
/*- Calls rdma_create_id() to get a cm_id	                      */
/*- And then calls rdma_resolve_addr()													*/
/*- Get the communication event																	*/
/*- Returns the event status:																		*/
/*	0: OK																									      */
/*	error: NOK  output device may be not a RNIC device					*/
/*- Calls rdma_destroy_id() to delete the cm_id created					*/
/*- Call rdma_destroy_event_channel  to close a channel event		*/

	int check_ofed_verbs_support (struct sockaddr *remoteaddr) 
			{
				struct rdma_event channel *cm_channel; 
				struct rdma_cm_id *cm_id; 
				int ret=0;
				cm_channel = rdma_create_event_channel(); 
				if (!cm_channel)  {
						fprintf(stderr,"rdma_create_event_channel error\n");
						return -1; 
						}
						ret = rdma_create_id(cm_channel, &cm_id, NULL, RDMA_PS_TCP);
						if (ret) {
								fprintf(stderr,"rdma_create_id: %d\n", ret);
								rdma_destroy_event_channel(cm_channel);
								return(ret);
						}
						ret = rdma_resolve_addr(cm_id, NULL, remoteaddr, RESOLVE_TIMEOUT_MS);
						if (ret) {
								fprintf(stderr,"rdma_resolve_addr: %d\n", ret);
								goto out;
						}
						ret = rdma_get_cm_event(cm_channel, &event); 
						if (ret) {
								fprintf(stderr," rdma_get_cm_event() failed\n");
								goto out;
						}
						ret = event->status;
						rdma_ack_cm_event(event);
			      out:
						rdma_destroy_id(cm_id);
						rdma_destroy_event_channel(cm_channel);
						return(ret);
			}