No-Path DAO Propagation

core/net/rpl/rpl-icmp6.c

@@ -709,20 +709,28 @@ dao_input(void)
 void
 dao_output(rpl_parent_t *n, uint8_t lifetime)
 {
-  rpl_dag_t *dag;
-  rpl_instance_t *instance;
-  unsigned char *buffer;
-  uint8_t prefixlen;
-  uip_ipaddr_t prefix;
-  int pos;
-
   /* Destination Advertisement Object */
+  uip_ipaddr_t prefix;
 
   if(get_global_addr(&prefix) == 0) {
     PRINTF("RPL: No global address set for this node - suppressing DAO\n");
     return;
   }
 
+  dao_output_target(n, &prefix, lifetime);
+}
+/*---------------------------------------------------------------------------*/
+void
+dao_output_target(rpl_parent_t *n, uip_ipaddr_t *prefix, uint8_t lifetime)
+{
+  rpl_dag_t *dag;
+  rpl_instance_t *instance;
+  unsigned char *buffer;
+  uint8_t prefixlen;
+  int pos;
+
+  /* Destination Advertisement Object */
+
   dag = n->dag;
   instance = dag->instance;
 
@@ -752,12 +760,12 @@ dao_output(rpl_parent_t *n, uint8_t lifetime)
 #endif /* RPL_DAO_SPECIFY_DAG */
 
   /* create target subopt */
-  prefixlen = sizeof(prefix) * CHAR_BIT;
+  prefixlen = sizeof(*prefix) * CHAR_BIT;
   buffer[pos++] = RPL_OPTION_TARGET;
   buffer[pos++] = 2 + ((prefixlen + 7) / CHAR_BIT);
   buffer[pos++] = 0; /* reserved */
   buffer[pos++] = prefixlen;
-  memcpy(buffer + pos, &prefix, (prefixlen + 7) / CHAR_BIT);
+  memcpy(buffer + pos, prefix, (prefixlen + 7) / CHAR_BIT);
   pos += ((prefixlen + 7) / CHAR_BIT);
 
   /* Create a transit information sub-option. */
@@ -769,7 +777,7 @@ dao_output(rpl_parent_t *n, uint8_t lifetime)
   buffer[pos++] = lifetime;
 
   PRINTF("RPL: Sending DAO with prefix ");
-  PRINT6ADDR(&prefix);
+  PRINT6ADDR(prefix);
   PRINTF(" to ");
   PRINT6ADDR(&n->addr);
   PRINTF("\n");

core/net/rpl/rpl-private.h

@@ -270,6 +270,7 @@ extern rpl_instance_t *default_instance;
 void dis_output(uip_ipaddr_t *addr);
 void dio_output(rpl_instance_t *, uip_ipaddr_t *uc_addr);
 void dao_output(rpl_parent_t *, uint8_t lifetime);
+void dao_output_target(rpl_parent_t *, uip_ipaddr_t *, uint8_t lifetime);
 void dao_ack_output(rpl_instance_t *, uip_ipaddr_t *, uint8_t);
 
 /* RPL logic functions. */

core/net/rpl/rpl.c

@@ -63,6 +63,8 @@ void
 rpl_purge_routes(void)
 {
   uip_ds6_route_t *r;
+  uip_ipaddr_t prefix;
+  rpl_dag_t *dag;
 
   /* First pass, decrement lifetime */
   r = uip_ds6_route_list_head();
@@ -86,8 +88,20 @@ rpl_purge_routes(void)
     if(r->state.lifetime < 1) {
       /* Routes with lifetime == 1 have only just been decremented from 2 to 1,
        * thus we want to keep them. Hence < and not <= */
+      uip_ipaddr_copy(&prefix, &r->ipaddr);
       uip_ds6_route_rm(r);
       r = uip_ds6_route_list_head();
+      PRINTF("No more routes to ");
+      PRINT6ADDR(&prefix);
+      dag = default_instance->current_dag;
+      /* Propagate this information with a No-Path DAO to preferred parent if we are not a RPL Root */
+      if(dag->rank != ROOT_RANK(default_instance)) {
+        PRINTF(" -> generate No-Path DAO\n");
+        dao_output_target(dag->preferred_parent, &prefix, RPL_ZERO_LIFETIME);
+        /* Don't schedule more than 1 No-Path DAO, let next iteration handle that */
+        return;
+      }
+      PRINTF("\n");
     } else {
       r = list_item_next(r);
     }