bgpd: bgp_sync_label_manager failure case

There are several problems with the bgp_sync_label_manager
function:

a) It is possible that a request in the lp->requests
fifo will be unable to be filled at this point in time
and the lf will be leaked and not ever fullfilled.

b) The bgp_sync_label_manager runs one time a second
irrelevant if there is work to do or not.

To fix (a) just add the request back to the requests
fifo and set the timer to pop in the future.

To fix (b) just every time something is put into
the request pool start a timer to run in 1 second
and do not restart it if all the work is done.

Signed-off-by: Donald Sharp <[email protected]>

bgpd/bgp_labelpool.c

@@ -36,6 +36,8 @@ static void lptest_init(void);
 static void lptest_finish(void);
 #endif
 
+static void bgp_sync_label_manager(struct event *e);
+
 /*
  * Remember where pool data are kept
  */
@@ -455,6 +457,9 @@ void bgp_lp_get(
 		if ((lp->next_chunksize << 1) <= LP_CHUNK_SIZE_MAX)
 			lp->next_chunksize <<= 1;
 	}
+
+	event_add_timer(bm->master, bgp_sync_label_manager, NULL, 1,
+			&bm->t_bgp_sync_label_manager);
 }
 
 void bgp_lp_release(
@@ -557,6 +562,10 @@ static void bgp_sync_label_manager(struct event *e)
 				zlog_debug("%s: out of labels, await more",
 					   __func__);
 			}
+
+			lp_fifo_add_tail(&lp->requests, lf);
+			event_add_timer(bm->master, bgp_sync_label_manager,
+					NULL, 1, &bm->t_bgp_sync_label_manager);
 			break;
 		}
 
@@ -582,9 +591,6 @@ static void bgp_sync_label_manager(struct event *e)
 finishedrequest:
 		XFREE(MTYPE_BGP_LABEL_FIFO, lf);
 	}
-
-	event_add_timer(bm->master, bgp_sync_label_manager, NULL, 1,
-			&bm->t_bgp_sync_label_manager);
 }
 
 void bgp_lp_event_chunk(uint32_t first, uint32_t last)