Merge pull request #652 from cetic/pr-rpl-rank-and-fw-errors

RPL rank and forward errors

core/net/ipv6/uip-ds6-nbr.c

@@ -227,11 +227,33 @@ uip_ds6_neighbor_periodic(void)
     switch(nbr->state) {
     case NBR_REACHABLE:
       if(stimer_expired(&nbr->reachable)) {
+#if UIP_CONF_IPV6_RPL
+        /* when a neighbor leave it's REACHABLE state and is a default router,
+           instead of going to STALE state it enters DELAY state in order to
+           force a NUD on it. Otherwise, if there is no upward traffic, the
+           node never knows if the default router is still reachable. This
+           mimics the 6LoWPAN-ND behavior.
+         */
+        if(uip_ds6_defrt_lookup(&nbr->ipaddr) != NULL) {
+          PRINTF("REACHABLE: defrt moving to DELAY (");
+          PRINT6ADDR(&nbr->ipaddr);
+          PRINTF(")\n");
+          nbr->state = NBR_DELAY;
+          stimer_set(&nbr->reachable, UIP_ND6_DELAY_FIRST_PROBE_TIME);
+          nbr->nscount = 0;
+        } else {
           PRINTF("REACHABLE: moving to STALE (");
           PRINT6ADDR(&nbr->ipaddr);
           PRINTF(")\n");
           nbr->state = NBR_STALE;
         }
+#else /* UIP_CONF_IPV6_RPL */
+        PRINTF("REACHABLE: moving to STALE (");
+        PRINT6ADDR(&nbr->ipaddr);
+        PRINTF(")\n");
+        nbr->state = NBR_STALE;
+#endif /* UIP_CONF_IPV6_RPL */
+      }
       break;
 #if UIP_ND6_SEND_NA
     case NBR_INCOMPLETE:

core/net/ipv6/uip6.c

@@ -1207,7 +1207,11 @@ uip_process(uint8_t flag)
       }
 
 #if UIP_CONF_IPV6_RPL
-      rpl_update_header_empty();
+      if(rpl_update_header_empty()) {
+        /* Packet can not be forwarded */
+        PRINTF("RPL Forward Option Error\n");
+        goto drop;
+      }
 #endif /* UIP_CONF_IPV6_RPL */
 
       UIP_IP_BUF->ttl = UIP_IP_BUF->ttl - 1;

core/net/rpl/rpl-dag.c

@@ -93,6 +93,13 @@ rpl_dag_init(void)
   nbr_table_register(rpl_parents, (nbr_table_callback *)nbr_callback);
 }
 /*---------------------------------------------------------------------------*/
+rpl_parent_t *
+rpl_get_parent(uip_lladdr_t *addr)
+{
+  rpl_parent_t *p = nbr_table_get_from_lladdr(rpl_parents, (linkaddr_t *)addr);
+  return p;
+}
+/*---------------------------------------------------------------------------*/
 rpl_rank_t
 rpl_get_parent_rank(uip_lladdr_t *addr)
 {

core/net/rpl/rpl-ext-header.c

@@ -48,6 +48,7 @@
 #include "net/ip/tcpip.h"
 #include "net/ipv6/uip-ds6.h"
 #include "net/rpl/rpl-private.h"
+#include "net/packetbuf.h"
 
 #define DEBUG DEBUG_NONE
 #include "net/ip/uip-debug.h"
@@ -105,19 +106,12 @@ rpl_verify_header(int uip_ext_opt_offset)
     route = uip_ds6_route_lookup(&UIP_IP_BUF->destipaddr);
     if(route != NULL) {
       uip_ds6_route_rm(route);
-
-      /* If we are the root and just needed to remove a DAO route,
-         chances are that the network needs to be repaired. The
-         rpl_repair_root() function will cause a global repair if we
-         happen to be the root node of the dag. */
-      PRINTF("RPL: initiate global repair\n");
-      rpl_repair_root(instance->instance_id);
     }
-
-    /* Remove the forwarding error flag and return 0 to let the packet
-       be forwarded again. */
-    UIP_EXT_HDR_OPT_RPL_BUF->flags &= ~RPL_HDR_OPT_FWD_ERR;
-    return 0;
+    RPL_STAT(rpl_stats.forward_errors++);
+    /* Trigger DAO retransmission */
+    rpl_reset_dio_timer(instance);
+    /* drop the packet as it is not routable */
+    return 1;
   }
 
   if(!instance->current_dag->joined) {
@@ -145,10 +139,9 @@ rpl_verify_header(int uip_ext_opt_offset)
 	   sender_closer);
     if(UIP_EXT_HDR_OPT_RPL_BUF->flags & RPL_HDR_OPT_RANK_ERR) {
       PRINTF("RPL: Rank error signalled in RPL option!\n");
-      /* We should try to repair it, not implemented for the moment */
+      /* Packet must be dropped and dio trickle timer reset, see RFC6550 - 11.2.2.2 */
       rpl_reset_dio_timer(instance);
-      /* Forward the packet anyway. */
-      return 0;
+      return 1;
     }
     PRINTF("RPL: Single error tolerated\n");
     UIP_EXT_HDR_OPT_RPL_BUF->flags |= RPL_HDR_OPT_RANK_ERR;
@@ -183,12 +176,13 @@ set_rpl_opt(unsigned uip_ext_opt_offset)
   }
 }
 /*---------------------------------------------------------------------------*/
-void
+int
 rpl_update_header_empty(void)
 {
   rpl_instance_t *instance;
   int uip_ext_opt_offset;
   int last_uip_ext_len;
+  rpl_parent_t *parent;
 
   last_uip_ext_len = uip_ext_len;
   uip_ext_len = 0;
@@ -211,12 +205,12 @@ rpl_update_header_empty(void)
     if(UIP_EXT_HDR_OPT_RPL_BUF->opt_len != RPL_HDR_OPT_LEN) {
       PRINTF("RPL: RPL Hop-by-hop option has wrong length\n");
       uip_ext_len = last_uip_ext_len;
-      return;
+      return 0;
     }
     instance = rpl_get_instance(UIP_EXT_HDR_OPT_RPL_BUF->instance);
     if(instance == NULL || !instance->used || !instance->current_dag->joined) {
       PRINTF("RPL: Unable to add hop-by-hop extension header: incorrect instance\n");
-      return;
+      return 0;
     }
     break;
   default:
@@ -224,11 +218,11 @@ rpl_update_header_empty(void)
     if(uip_len + RPL_HOP_BY_HOP_LEN > UIP_BUFSIZE) {
       PRINTF("RPL: Packet too long: impossible to add hop-by-hop option\n");
       uip_ext_len = last_uip_ext_len;
-      return;
+      return 0;
     }
     set_rpl_opt(uip_ext_opt_offset);
     uip_ext_len = last_uip_ext_len + RPL_HOP_BY_HOP_LEN;
-    return;
+    return 0;
   }
 
   switch(UIP_EXT_HDR_OPT_BUF->type) {
@@ -244,6 +238,15 @@ rpl_update_header_empty(void)
       if(uip_ds6_route_lookup(&UIP_IP_BUF->destipaddr) == NULL) {
         UIP_EXT_HDR_OPT_RPL_BUF->flags |= RPL_HDR_OPT_FWD_ERR;
         PRINTF("RPL forwarding error\n");
+        /* We should send back the packet to the originating parent,
+           but it is not feasible yet, so we send a No-Path DAO instead */
+        PRINTF("RPL generate No-Path DAO\n");
+        parent = rpl_get_parent((uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_SENDER));
+        if(parent != NULL) {
+          dao_output_target(parent, &UIP_IP_BUF->destipaddr, RPL_ZERO_LIFETIME);
+        }
+        /* Drop packet */
+        return 1;
       }
     } else {
       /* Set the down extension flag correctly as described in Section
@@ -262,11 +265,11 @@ rpl_update_header_empty(void)
     }
 
     uip_ext_len = last_uip_ext_len;
-    return;
+    return 0;
   default:
     PRINTF("RPL: Multi Hop-by-hop options not implemented\n");
     uip_ext_len = last_uip_ext_len;
-    return;
+    return 0;
   }
 }
 /*---------------------------------------------------------------------------*/

core/net/rpl/rpl.h

@@ -240,13 +240,14 @@ int rpl_repair_root(uint8_t instance_id);
 int rpl_set_default_route(rpl_instance_t *instance, uip_ipaddr_t *from);
 rpl_dag_t *rpl_get_any_dag(void);
 rpl_instance_t *rpl_get_instance(uint8_t instance_id);
-void rpl_update_header_empty(void);
+int rpl_update_header_empty(void);
 int rpl_update_header_final(uip_ipaddr_t *addr);
 int rpl_verify_header(int);
 void rpl_insert_header(void);
 void rpl_remove_header(void);
 uint8_t rpl_invert_header(void);
 uip_ipaddr_t *rpl_get_parent_ipaddr(rpl_parent_t *nbr);
+rpl_parent_t *rpl_get_parent(uip_lladdr_t *addr);
 rpl_rank_t rpl_get_parent_rank(uip_lladdr_t *addr);
 uint16_t rpl_get_parent_link_metric(const uip_lladdr_t *addr);
 void rpl_dag_init(void);