tsch: add start sending EB when a node joins RPL newwork in tsch.

os/net/mac/tsch/tsch.c

@@ -862,6 +862,12 @@ PROCESS_THREAD(tsch_send_eb_process, ev, data)
     unsigned long delay;
 
     if(tsch_is_associated && tsch_current_eb_period > 0) {
+#ifdef TSCH_RPL_CHECK_DODAG_JOINED
+      /* Implementation section 6.3 of RFC 8180 */
+      if(!TSCH_RPL_CHECK_DODAG_JOINED()) {
+        goto tsch_send_eb_skipped;
+      }
+#endif /* TSCH_RPL_CHECK_DODAG_JOINED */
       /* Enqueue EB only if there isn't already one in queue */
       if(tsch_queue_packet_count(&tsch_eb_address) == 0) {
         uint8_t hdr_len = 0;
@@ -881,6 +887,9 @@ PROCESS_THREAD(tsch_send_eb_process, ev, data)
         }
       }
     }
+#ifdef TSCH_RPL_CHECK_DODAG_JOINED
+tsch_send_eb_skipped:
+#endif /* TSCH_RPL_CHECK_DODAG_JOINED */
     if(tsch_current_eb_period > 0) {
       /* Next EB transmission with a random delay
        * within [tsch_current_eb_period*0.75, tsch_current_eb_period[ */

os/net/mac/tsch/tsch.h

@@ -88,6 +88,10 @@ frequency hopping for enhanced reliability.
 #define TSCH_CALLBACK_KA_SENT tsch_rpl_callback_ka_sent
 #endif /* TSCH_CALLBACK_KA_SENT */
 
+#ifndef TSCH_RPL_CHECK_DODAG_JOINED
+#define TSCH_RPL_CHECK_DODAG_JOINED tsch_rpl_check_dodag_joined
+#endif /* TSCH_RPL_CHECK_DODAG_JOINED */
+
 #endif /* UIP_CONF_IPV6_RPL */
 
 #if BUILD_WITH_ORCHESTRA
@@ -117,6 +121,11 @@ void TSCH_CALLBACK_LEAVING_NETWORK();
 void TSCH_CALLBACK_KA_SENT();
 #endif
 
+/* Called by TSCH before sending a EB */
+#ifdef TSCH_RPL_CHECK_DODAG_JOINED
+int TSCH_RPL_CHECK_DODAG_JOINED();
+#endif
+
 /* Called by TSCH form interrupt after receiving a frame, enabled upper-layer to decide
  * whether to ACK or NACK */
 #ifdef TSCH_CALLBACK_DO_NACK