net/mld: There is an issue with the general query timer design. There should be a single instance, not a per-group instance of the timer (ditto for the v1 compatibility timer). Fall back for now and use the per-group MAX query.

TODO

@@ -19,7 +19,7 @@ nuttx/:
   (9)  Kernel/Protected Build
   (3)  C++ Support
   (5)  Binary loaders (binfmt/)
- (18)  Network (net/, drivers/net)
+ (19)  Network (net/, drivers/net)
   (4)  USB (drivers/usbdev, drivers/usbhost)
   (2)  Other drivers (drivers/)
  (11)  Libraries (libs/libc/, libs/libm/)
@@ -1497,6 +1497,9 @@ o Network (net/, drivers/net)
                Instead, the design currently uses a Multicast Address Specific
                Query with one timer per group and ignores groups that we are
                not members of.
+
+               Similary, the MLDv1 compatibility timer should be a single,
+               separate timer, not a per-group timer.
   Status:      Open
   Priority:    Low.  There are no customers of MLD as far as I know.
 

net/mld/mld.h

@@ -189,7 +189,7 @@ enum mld_msgtype_e
 {
   MLD_SEND_NONE = 0,           /* Nothing to send */
   MLD_SEND_GENQUERY,           /* Send General Query */
-  MLD_SEND_MASQUERY,           /* Send Multicast Address Specific (MAS) Query */
+  MLD_SEND_MASQUERY,           /* Send General Query */
   MLD_SEND_V1REPORT,           /* Send MLDv1 Report message */
   MLD_SEND_V2REPORT,           /* Send MLDv2 Report message */
   MLD_SEND_DONE                /* Send Done message */

net/mld/mld_timer.c

@@ -188,10 +188,22 @@ static void mld_polldog_work(FAR void *arg)
 
   if (IS_MLD_QUERIER(group->flags))
     {
-      /* Schedule (and forget) the general query. */
+      /* Schedule (and forget) the general query or MAS query. */
 
       MLD_STATINCR(g_netstats.mld.query_sched);
+
+#ifdef CONFIG_NET_MLD_ROUTER
+      /* REVISIT:  In order to support the RFC correctly, we would need
+       * separate, single general query timer that is not part of the
+       * group structure. The Querier should query across all groups,
+       * with a single query, not very via multiple MAS queries as is
+       * done here.
+       */
+
       ret = mld_schedmsg(group, MLD_SEND_GENQUERY);
+#else
+      ret = mld_schedmsg(group, MLD_SEND_MASQUERY);
+#endif
       if (ret < 0)
         {
           mlderr("ERROR: Failed to schedule message: %d\n", ret);
@@ -363,6 +375,8 @@ void mld_start_polltimer(FAR struct mld_group_s *group, clock_t ticks)
  * Description:
  *   Start the MLDv1 compatibility timer.
  *
+ *   REVISIT:  This should be a single global timer, not a per-group timer.
+ *
  ****************************************************************************/
 
 void mld_start_v1timer(FAR struct mld_group_s *group, clock_t ticks)