Merge pull request #21759 from elenaf9/gnrc/rpl/different-dodags

gnrc/rpl: switching between DODAGs

Author: crasbe

sys/include/net/gnrc/rpl.h

@@ -439,18 +439,84 @@ static inline bool GNRC_RPL_COUNTER_GREATER_THAN(uint8_t A, uint8_t B)
  *      </a>
  * @{
  */
+/**
+ * @brief   Type ID of the Pad1 option.
+ */
 #define GNRC_RPL_OPT_PAD1                 (0)
+/**
+ * @brief   Type ID of the PadN option.
+ */
 #define GNRC_RPL_OPT_PADN                 (1)
+/**
+ * @brief   Type ID of the DAG Metric Container option.
+ */
 #define GNRC_RPL_OPT_DAG_METRIC_CONTAINER (2)
+/**
+ * @brief   Type ID of the Route Information option.
+ */
 #define GNRC_RPL_OPT_ROUTE_INFO           (3)
+/**
+ * @brief   Type ID of the DODAG Configuration option.
+ */
 #define GNRC_RPL_OPT_DODAG_CONF           (4)
+/**
+ * @brief   Type ID of the RPL Target option.
+ */
 #define GNRC_RPL_OPT_TARGET               (5)
+/**
+ * @brief   Type ID of the Transit Information option.
+ */
 #define GNRC_RPL_OPT_TRANSIT              (6)
+/**
+ * @brief   Shift of the External 'E' flag in the Transit
+ *          Information flags.
+ */
+#define GNRC_RPL_OPT_TRANSIT_E_FLAG_SHIFT (7)
+/**
+ * @brief   Type ID of the Solocited option.
+ */
 #define GNRC_RPL_OPT_SOLICITED_INFO       (7)
+/**
+ * @brief   Type ID of the Prefix Information option.
+ */
 #define GNRC_RPL_OPT_PREFIX_INFO          (8)
+/**
+ * @brief   Shift of the autnomous address-configuration
+ *          'A' flag in the Prefix Information option.
+ */
+#define GNRC_RPL_PREFIX_AUTO_ADDRESS_BIT  (1 << 6)
+/**
+ * @brief   Type ID of the RPL Target Descriptor option.
+ */
 #define GNRC_RPL_OPT_TARGET_DESC          (9)
 /** @} */
 
+/**
+ * @name RPL DIO Base Object fields
+ *  @see <a href="https://tools.ietf.org/html/rfc6550#section-6.3">
+ *          DODAG Information Object (DIO)
+ *      </a>
+ * @{
+ */
+/**
+ * @brief   Shift of the Grounded 'G' flag in the DIO.
+ */
+#define GNRC_RPL_GROUNDED_SHIFT             (7)
+/**
+ * @brief   Shift of the Mode of Operation (MOP) field in the DIO.
+ */
+#define GNRC_RPL_MOP_SHIFT                  (3)
+/**
+ * @brief   Mask for the 3 MOP bits.
+ */
+#define GNRC_RPL_SHIFTED_MOP_MASK           (0x7)
+/**
+ * @brief   Mask for the 3 PRF bits.
+ */
+#define GNRC_RPL_PRF_MASK                   (0x7)
+/** @} */
+
+
 /**
  * @brief Rank of the root node
  */

sys/include/net/gnrc/rpl/dodag.h

@@ -76,15 +76,19 @@ bool gnrc_rpl_instance_add(uint8_t instance_id, gnrc_rpl_instance_t **inst);
  */
 bool gnrc_rpl_instance_remove_by_id(uint8_t instance_id);
 
+/**
+ * @brief   Remove a RPL DODAG with the pointer @p dodag from its instance.
+ *
+ * @param[in] dodag     Pointer to the RPL DODAG to remove.
+ */
+void gnrc_rpl_dodag_remove(gnrc_rpl_dodag_t *dodag);
+
 /**
  * @brief   Remove a RPL instance with the pointer @p inst.
  *
  * @param[in] inst     Pointer to the RPL instance to remove.
- *
- * @return  true, on success.
- * @return  false, otherwise.
  */
-bool gnrc_rpl_instance_remove(gnrc_rpl_instance_t *inst);
+void gnrc_rpl_instance_remove(gnrc_rpl_instance_t *inst);
 
 /**
  * @brief   Get the RPL instance with the id @p instance_id.

sys/include/net/gnrc/rpl/structs.h

@@ -286,7 +286,7 @@ typedef struct {
      * @return      Negative, if the first parent is preferred.
      */
     int (*parent_cmp)(gnrc_rpl_parent_t *parent1, gnrc_rpl_parent_t *parent2);
-    gnrc_rpl_dodag_t *(*which_dodag)(gnrc_rpl_dodag_t *, gnrc_rpl_dodag_t *); /**< compare for dodags */
+    int (*which_dodag)(gnrc_rpl_dodag_t *, gnrc_rpl_dio_t *); /**< compare for dodags */
 
     /**
      * @brief Reset the state of the objective function.

sys/net/gnrc/routing/rpl/gnrc_rpl_control_messages.c

@@ -35,6 +35,7 @@
 #include "net/gnrc.h"
 #include "net/eui64.h"
 #include "gnrc_rpl_internal/globals.h"
+#include "of0.h"
 
 #ifdef MODULE_NETSTATS_RPL
 #include "gnrc_rpl_internal/netstats.h"
@@ -54,14 +55,6 @@
 
 static char addr_str[IPV6_ADDR_MAX_STR_LEN];
 
-#define GNRC_RPL_GROUNDED_SHIFT             (7)
-#define GNRC_RPL_MOP_SHIFT                  (3)
-#define GNRC_RPL_OPT_TRANSIT_E_FLAG_SHIFT   (7)
-#define GNRC_RPL_OPT_TRANSIT_E_FLAG         (1 << GNRC_RPL_OPT_TRANSIT_E_FLAG_SHIFT)
-#define GNRC_RPL_SHIFTED_MOP_MASK           (0x7)
-#define GNRC_RPL_PRF_MASK                   (0x7)
-#define GNRC_RPL_PREFIX_AUTO_ADDRESS_BIT    (1 << 6)
-
 /**
  * @brief   Checks validity of DIO control messages
  *
@@ -628,7 +621,7 @@ static bool _parse_options(int msg_type, gnrc_rpl_instance_t *inst, gnrc_rpl_opt
 
             /* check the DODAG ID */
             if (sol->VID_flags & GNRC_RPL_DIS_SOLICITED_INFO_FLAG_D) {
-                if (memcmp(&sol->dodag_id, &inst->dodag.dodag_id, sizeof(ipv6_addr_t)) != 0) {
+                if (!ipv6_addr_equal(&sol->dodag_id, &inst->dodag.dodag_id)) {
                     DEBUG("RPL: RPL SOLICITED INFO option, ignore DIS cause: DODAGID mismatch\n");
                     return false;
                 }
@@ -905,6 +898,42 @@ void _recv_DIO_for_new_dodag(gnrc_rpl_instance_t *inst, gnrc_rpl_dio_t *dio, ker
 
 }
 
+/**
+ * @brief   Handles a received DIO message for a DODAG that is different from the
+ *          one we currently participate in.
+ *
+ * @param[in] inst      The @p RPL instance of the current DODAG.
+ * @param[in] dio       The @p DIO packet for the other DODAG.
+ * @param[in] src       The address of the sender.
+ * @param[in] len       The length of the DIO packet.
+ */
+static void _recv_DIO_for_different_dodag(gnrc_rpl_instance_t *inst, gnrc_rpl_dio_t *dio,
+                                          kernel_pid_t iface,
+                                          ipv6_addr_t *src, uint16_t len)
+{
+    /* DIO received from a different DODAG */
+    DEBUG("RPL: DIO received from another DODAG, but same instance.\n");
+
+    gnrc_rpl_dodag_t *dodag = &inst->dodag;
+
+    /* clear parent from old dodag if present */
+    gnrc_rpl_parent_t *parent = dodag->parents;
+    while (parent) {
+        if (ipv6_addr_equal(&parent->addr, src)) {
+            gnrc_rpl_parent_remove(parent);
+            break;
+        }
+        parent = parent->next;
+    }
+
+    /* decide between old and new dodag */
+    if (gnrc_rpl_get_of0()->which_dodag(dodag, dio) > 0) {
+        DEBUG("RPL: switch to new DODAG.\n");
+        gnrc_rpl_dodag_remove(dodag);
+        _recv_DIO_for_new_dodag(inst, dio, iface, src, len);
+    }
+}
+
 /**
  * @brief   Handles a received DIO message for an existing DODAG.
  *
@@ -914,17 +943,11 @@ void _recv_DIO_for_new_dodag(gnrc_rpl_instance_t *inst, gnrc_rpl_dio_t *dio, ker
  * @param[in] len       The length of the DIO packet.
  */
 static void _recv_DIO_for_existing_dodag(gnrc_rpl_instance_t *inst, gnrc_rpl_dio_t *dio,
-                                         ipv6_addr_t *src, uint16_t len)
+                                         ipv6_addr_t *src,
+                                         uint16_t len)
 {
     gnrc_rpl_dodag_t *dodag = &inst->dodag;
 
-    /* ignore dodags with other dodag_id's for now */
-    /* TODO: choose DODAG with better rank */
-    if (memcmp(&dodag->dodag_id, &dio->dodag_id, sizeof(ipv6_addr_t)) != 0) {
-        DEBUG("RPL: DIO received from another DODAG, but same instance - ignore\n");
-        return;
-    }
-
     if (inst->mop != ((dio->g_mop_prf >> GNRC_RPL_MOP_SHIFT) & GNRC_RPL_SHIFTED_MOP_MASK)) {
         DEBUG("RPL: invalid MOP for this instance.\n");
         return;
@@ -937,21 +960,6 @@ static void _recv_DIO_for_existing_dodag(gnrc_rpl_instance_t *inst, gnrc_rpl_dio
     }
 #endif
 
-    if (GNRC_RPL_COUNTER_GREATER_THAN(dio->version_number, dodag->version)) {
-        if (dodag->node_status == GNRC_RPL_ROOT_NODE) {
-            dodag->version = GNRC_RPL_COUNTER_INCREMENT(dio->version_number);
-            trickle_reset_timer(&dodag->trickle);
-        }
-        else {
-            dodag->version = dio->version_number;
-            gnrc_rpl_local_repair(dodag);
-        }
-    }
-    else if (GNRC_RPL_COUNTER_GREATER_THAN(dodag->version, dio->version_number)) {
-        trickle_reset_timer(&dodag->trickle);
-        return;
-    }
-
     if (dodag->node_status == GNRC_RPL_ROOT_NODE) {
         if (byteorder_ntohs(dio->rank) != GNRC_RPL_INFINITE_RANK) {
             trickle_increment_counter(&dodag->trickle);
@@ -996,6 +1004,11 @@ void gnrc_rpl_recv_DIO(gnrc_rpl_dio_t *dio, kernel_pid_t iface, ipv6_addr_t *src
     else if (inst == NULL) {
         DEBUG("RPL: Could not allocate a new instance.\n");
     }
+    else if (!ipv6_addr_equal(&inst->dodag.dodag_id, &dio->dodag_id)
+             || (inst->dodag.version != dio->version_number)) {
+
+        _recv_DIO_for_different_dodag(inst, dio, iface, src, len);
+    }
     else {
         _recv_DIO_for_existing_dodag(inst, dio, src, len);
     }
@@ -1256,7 +1269,7 @@ void gnrc_rpl_recv_DAO(gnrc_rpl_dao_t *dao, kernel_pid_t iface, ipv6_addr_t *src
 
     /* check if the D flag is set before accessing the DODAG id */
     if ((dao->k_d_flags & GNRC_RPL_DAO_D_BIT)) {
-        if (memcmp(&dodag->dodag_id, (ipv6_addr_t *)(dao + 1), sizeof(ipv6_addr_t)) != 0) {
+        if (!ipv6_addr_equal(&dodag->dodag_id, (ipv6_addr_t *)(dao + 1))) {
             DEBUG("RPL: DAO with unknown DODAG id (%s)\n", _ip_addr_str((ipv6_addr_t *)(dao + 1)));
             return;
         }
@@ -1319,7 +1332,7 @@ void gnrc_rpl_recv_DAO_ACK(gnrc_rpl_dao_ack_t *dao_ack, kernel_pid_t iface, ipv6
 
     /* check if the D flag is set before accessing the DODAG id */
     if ((dao_ack->d_reserved & GNRC_RPL_DAO_ACK_D_BIT)) {
-        if (memcmp(&dodag->dodag_id, (ipv6_addr_t *)(dao_ack + 1), sizeof(ipv6_addr_t)) != 0) {
+        if (!ipv6_addr_equal(&dodag->dodag_id, (ipv6_addr_t *)(dao_ack + 1))) {
             DEBUG("RPL: DAO-ACK with unknown DODAG id (%s)\n",
                   _ip_addr_str((ipv6_addr_t *)(dao_ack + 1)));
             return;

sys/net/gnrc/routing/rpl/gnrc_rpl_dodag.c

@@ -115,24 +115,29 @@ bool gnrc_rpl_instance_remove_by_id(uint8_t instance_id)
 {
     for(uint8_t i = 0; i < GNRC_RPL_INSTANCES_NUMOF; ++i) {
         if (gnrc_rpl_instances[i].id == instance_id) {
-            return gnrc_rpl_instance_remove(&gnrc_rpl_instances[i]);
+            gnrc_rpl_instance_remove(&gnrc_rpl_instances[i]);
+            return true;
         }
     }
     return false;
 }
 
-bool gnrc_rpl_instance_remove(gnrc_rpl_instance_t *inst)
+void gnrc_rpl_dodag_remove(gnrc_rpl_dodag_t *dodag)
 {
-    gnrc_rpl_dodag_t *dodag = &inst->dodag;
 #ifdef MODULE_GNRC_RPL_P2P
     gnrc_rpl_p2p_ext_remove(dodag);
 #endif
     gnrc_rpl_dodag_remove_all_parents(dodag);
     trickle_stop(&dodag->trickle);
     evtimer_del(&gnrc_rpl_evtimer, (evtimer_event_t *)&dodag->dao_event);
-    evtimer_del(&gnrc_rpl_evtimer, (evtimer_event_t *)&inst->cleanup_event);
+    evtimer_del(&gnrc_rpl_evtimer, (evtimer_event_t *)&dodag->instance->cleanup_event);
+
+}
+
+void gnrc_rpl_instance_remove(gnrc_rpl_instance_t *inst)
+{
+    gnrc_rpl_dodag_remove(&inst->dodag);
     memset(inst, 0, sizeof(gnrc_rpl_instance_t));
-    return true;
 }
 
 gnrc_rpl_instance_t *gnrc_rpl_instance_get(uint8_t instance_id)

sys/net/gnrc/routing/rpl/of0.c

@@ -25,18 +25,18 @@
 
 static uint16_t calc_rank(gnrc_rpl_dodag_t *, uint16_t);
 static int parent_cmp(gnrc_rpl_parent_t *, gnrc_rpl_parent_t *);
-static gnrc_rpl_dodag_t *which_dodag(gnrc_rpl_dodag_t *, gnrc_rpl_dodag_t *);
+static int which_dodag(gnrc_rpl_dodag_t *, gnrc_rpl_dio_t *);
 static void reset(gnrc_rpl_dodag_t *);
 
 static gnrc_rpl_of_t gnrc_rpl_of0 = {
-    .ocp          = 0x0,
-    .calc_rank    = calc_rank,
-    .parent_cmp   = parent_cmp,
-    .which_dodag  = which_dodag,
-    .reset        = reset,
+    .ocp = 0x0,
+    .calc_rank = calc_rank,
+    .parent_cmp = parent_cmp,
+    .which_dodag = which_dodag,
+    .reset = reset,
     .parent_state_callback = NULL,
-    .init         = NULL,
-    .process_dio  = NULL
+    .init = NULL,
+    .process_dio = NULL
 };
 
 gnrc_rpl_of_t *gnrc_rpl_get_of0(void)
@@ -87,9 +87,59 @@ int parent_cmp(gnrc_rpl_parent_t *parent1, gnrc_rpl_parent_t *parent2)
     return 0;
 }
 
-/* Not used yet */
-gnrc_rpl_dodag_t *which_dodag(gnrc_rpl_dodag_t *d1, gnrc_rpl_dodag_t *d2)
+int which_dodag(gnrc_rpl_dodag_t *d1, gnrc_rpl_dio_t *dio)
 {
-    (void) d2;
-    return d1;
+    /* RFC 6552, Section 4.2 */
+
+    /* parent set must not be empty */
+    if ((d1->node_status != GNRC_RPL_ROOT_NODE) && !d1->parents) {
+        return 1;
+    }
+
+    /* prefer grounded dodag */
+    int dio_grounded = dio->g_mop_prf >> GNRC_RPL_GROUNDED_SHIFT;
+    if (d1->grounded > dio_grounded) {
+        return -1;
+    }
+    else if (dio_grounded > d1->grounded) {
+        return 1;
+    }
+
+    int dio_prf = dio->g_mop_prf & GNRC_RPL_PRF_MASK;
+
+    /* prefer dodag with more preferable root */
+    if (d1->prf > dio_prf) {
+        return -1;
+    }
+    else if (dio_prf > d1->prf) {
+        return 1;
+    }
+
+    /* prefer DODAG with more recent version */
+    if (ipv6_addr_equal(&d1->dodag_id, &dio->dodag_id)) {
+        if (GNRC_RPL_COUNTER_GREATER_THAN(d1->version, dio->version_number)) {
+            return -1;
+        }
+        else if (GNRC_RPL_COUNTER_GREATER_THAN(dio->version_number, d1->version)) {
+            return 1;
+        }
+    }
+
+    /* prefer dodag with lesser resulting rank */
+    /* TODO: calc rank properly */
+    int d1_rank = d1->parents->rank;
+    int d2_rank = byteorder_ntohs(dio->rank);
+    if (d1_rank < d2_rank) {
+        return -1;
+    }
+    else if (d2_rank < d1_rank) {
+        return 1;
+    }
+
+    /* prefer DODAG for which there is an alternate parent */
+    if (d1->parents->next) {
+        return -1;
+    }
+
+    return 0;
 }