fix(internal): Correct potential nil pointer err

[ric-plt/lib/rmr.git] / src / rmr / nanomsg / src / rtable_static.c

diff --git a/src/rmr/nanomsg/src/rtable_static.c b/src/rmr/nanomsg/src/rtable_static.c
index cfcb27e..643f00a 100644 (file)
--- a/src/rmr/nanomsg/src/rtable_static.c
+++ b/src/rmr/nanomsg/src/rtable_static.c
@@ -203,6 +203,13 @@ static int uta_epsock_byname( route_table_t* rt, char* ep_name ) {
        with group 0. If more is set, the caller may increase the group number and
        invoke this function again to make a selection against that group. If there
        are no more groups, more is set to 0.
+
+       NOTE:   The round robin selection index increment might collide with other
+               threads if multiple threads are attempting to send to the same round
+               robin group; the consequences are small and avoid locking. The only side
+               effect is either sending two messages in a row to, or skipping, an endpoint.
+               Both of these, in the grand scheme of things, is minor compared to the
+               overhead of grabbing a lock on each call.
 */
 static int uta_epsock_rr( route_table_t *rt, uint64_t key, int group, int* more ) {
        rtable_ent_t* rte;                      // matching rt entry
@@ -210,6 +217,7 @@ static int uta_epsock_rr( route_table_t *rt, uint64_t key, int group, int* more
        int nn_sock = -2;
        int dummy;
        rrgroup_t* rrg;
+       int     idx;
 
 
        if( ! more ) {                          // eliminate checks each time we need to use
@@ -252,11 +260,9 @@ static int uta_epsock_rr( route_table_t *rt, uint64_t key, int group, int* more
                        break;
 
                default:                                                                                // need to pick one and adjust rr counts
-                       ep = rrg->epts[rrg->ep_idx];
-                       nn_sock = rrg->epts[rrg->ep_idx++]->nn_sock;
-                       if( rrg->ep_idx >= rrg->nused ) {
-                               rrg->ep_idx = 0;
-                       }
+                       idx = rrg->ep_idx++ % rrg->nused;                       // see note above
+                       ep = rrg->epts[idx];
+                       nn_sock = ep->nn_sock;
                        break;
        }