This commit includes the iisc pnf_p7 slot tick fix

It also includes the queuing development. The idea
is that the 5G Userplane messages will be filled
and configured the same as previous commit, but
the uplink messages will be queued and then sent to
the gNB during the correct slot. Still WIP.

nfapi/open-nFAPI/pnf/src/pnf_p7.c

@@ -3206,6 +3206,38 @@ int pnf_p7_message_pump(pnf_p7_t* pnf_p7)
 	return 0;
 }
 
+struct timespec pnf_timespec_add(struct timespec lhs, struct timespec rhs)
+{
+	struct timespec result;
+
+	result.tv_sec = lhs.tv_sec + rhs.tv_sec;
+	result.tv_nsec = lhs.tv_nsec + rhs.tv_nsec;
+
+	if(result.tv_nsec > 1e9)
+	{
+		result.tv_sec++;
+		result.tv_nsec-= 1e9;
+	}
+
+	return result;
+}
+
+struct timespec pnf_timespec_sub(struct timespec lhs, struct timespec rhs)
+{
+	struct timespec result;
+	if ((lhs.tv_nsec-rhs.tv_nsec)<0) 
+	{
+		result.tv_sec = lhs.tv_sec-rhs.tv_sec-1;
+		result.tv_nsec = 1000000000+lhs.tv_nsec-rhs.tv_nsec;
+	} 
+	else 
+	{
+		result.tv_sec = lhs.tv_sec-rhs.tv_sec;
+		result.tv_nsec = lhs.tv_nsec-rhs.tv_nsec;
+	}
+	return result;
+}
+
 int pnf_nr_p7_message_pump(pnf_p7_t* pnf_p7)
 {
 
@@ -3281,6 +3313,23 @@ int pnf_nr_p7_message_pump(pnf_p7_t* pnf_p7)
 	}
 	NFAPI_TRACE(NFAPI_TRACE_INFO, "PNF P7 bind succeeded...\n");
 
+	//Initializaing timing structures needed for slot ticking 
+
+	struct timespec slot_start;
+	clock_gettime(CLOCK_MONOTONIC, &slot_start);
+
+	struct timespec pselect_start;
+
+	struct timespec timeout;
+	timeout.tv_sec = 0;
+	timeout.tv_nsec = 500000;
+
+	struct timespec slot_duration; 
+	slot_duration.tv_sec = 0;
+	slot_duration.tv_nsec = 0.5e6;
+
+	//Infinite loop 
+
 	while(pnf_p7->terminate == 0)
 	{
 		fd_set rfds;
@@ -3290,11 +3339,26 @@ int pnf_nr_p7_message_pump(pnf_p7_t* pnf_p7)
 		FD_ZERO(&rfds);
 		FD_SET(pnf_p7->p7_sock, &rfds);
 
-		struct timeval timeout;
-		timeout.tv_sec = 1;
-		timeout.tv_usec = 0;
+		clock_gettime(CLOCK_MONOTONIC, &pselect_start);
 
-		selectRetval = select(pnf_p7->p7_sock+1, &rfds, NULL, NULL, &timeout);
+		//setting the timeout
+
+		if((pselect_start.tv_sec > slot_start.tv_sec) || ((pselect_start.tv_sec == slot_start.tv_sec) && (pselect_start.tv_nsec > slot_start.tv_nsec)))
+		{
+			// overran the end of the subframe we do not want to wait
+			timeout.tv_sec = 0;
+			timeout.tv_nsec = 0;
+
+			//struct timespec overrun = pnf_timespec_sub(pselect_start, sf_start);
+			//NFAPI_TRACE(NFAPI_TRACE_INFO, "Subframe overrun detected of %d.%d running to catchup\n", overrun.tv_sec, overrun.tv_nsec);
+		}
+		else
+		{
+			// still time before the end of the subframe wait
+			timeout = pnf_timespec_sub(slot_start, pselect_start);
+		}
+
+		selectRetval = pselect(pnf_p7->p7_sock+1, &rfds, NULL, NULL, &timeout, NULL);
 
 		uint32_t now_hr_time = pnf_get_current_time_hr();
 
@@ -3304,6 +3368,17 @@ int pnf_nr_p7_message_pump(pnf_p7_t* pnf_p7)
 		if(selectRetval == 0)
 		{	
 			// timeout
+
+			//update slot start timing
+			slot_start = pnf_timespec_add(slot_start, slot_duration);
+
+			//increment sfn/slot
+			if (++pnf_p7->slot == 20)
+                        {
+                                pnf_p7->slot = 0;
+                                pnf_p7->sfn = (pnf_p7->sfn + 1) % 1024;
+                        }
+
 			continue;
 		}
 		else if (selectRetval == -1 && (errno == EINTR))
@@ -3322,7 +3397,7 @@ int pnf_nr_p7_message_pump(pnf_p7_t* pnf_p7)
 		if(FD_ISSET(pnf_p7->p7_sock, &rfds)) 
 
 		{
-			pnf_nr_nfapi_p7_read_dispatch_message(pnf_p7, now_hr_time);
+			pnf_nr_nfapi_p7_read_dispatch_message(pnf_p7, now_hr_time); 
 		}
 	}
 		NFAPI_TRACE(NFAPI_TRACE_ERROR, "PNF_P7 Terminating..\n");