Corrected frame counter handling on re-discovery

Frame counters were not correctly set when key was inserted after
re-discovery (where it had been removed from MAC). Now there are
own values for stored and current frame counters to fix that.

Also added check that frame counters are read only once from nvm.

Author: Mika Leppänen

source/6LoWPAN/ws/ws_pae_controller.c

@@ -88,6 +88,7 @@ typedef struct {
     bool gtks_set : 1;                                               /**< GTKs are set */
     bool gtkhash_set : 1;                                            /**< GTK hashes are set */
     bool key_index_set : 1;                                          /**< NW key index is set */
+    bool frame_counter_read : 1;                                     /**< Frame counters has been read */
 } pae_controller_t;
 
 typedef struct {
@@ -380,9 +381,11 @@ static int8_t ws_pae_controller_nw_key_check_and_insert(protocol_interface_info_
                 // Read current counter from MAC
                 uint32_t curr_frame_counter;
                 controller->nw_frame_counter_read(controller->interface_ptr, &curr_frame_counter, i);
+
                 // If stored frame counter is greater than MAC counter
                 if (controller->frame_counters.counter[i].frame_counter > curr_frame_counter) {
-                    tr_debug("Frame counter set: %i, stored %"PRIu32" current: %"PRIu32"", i, controller->frame_counters.counter[i].frame_counter, curr_frame_counter);
+                    tr_debug("Frame counter set: %i, stored %"PRIu32" current: %"PRIu32"", i,
+                             controller->frame_counters.counter[i].frame_counter, curr_frame_counter);
                     curr_frame_counter = controller->frame_counters.counter[i].frame_counter;
                     // Updates MAC frame counter
                     controller->nw_frame_counter_set(controller->interface_ptr, curr_frame_counter, i);
@@ -474,6 +477,9 @@ void ws_pae_controller_nw_keys_remove(protocol_interface_info_entry_t *interface
         return;
     }
 
+    /* Checks if frame counters needs to be stored when keys are removed */
+    ws_pae_controller_frame_counter_store(controller, true);
+
     tr_info("NW keys remove");
 
     nw_key_t *nw_key = controller->nw_key;
@@ -589,6 +595,7 @@ static void ws_pae_controller_data_init(pae_controller_t *controller)
     controller->gtks_set = false;
     controller->gtkhash_set = false;
     controller->key_index_set = false;
+    controller->frame_counter_read = false;
     controller->gtk_index = -1;
     controller->network_name = NULL;
     controller->frame_cnt_store_timer = FRAME_COUNTER_STORE_INTERVAL;
@@ -602,6 +609,11 @@ static void ws_pae_controller_data_init(pae_controller_t *controller)
 
 static void ws_pae_controller_frame_counter_read(pae_controller_t *controller)
 {
+    if (controller->frame_counter_read) {
+        return;
+    }
+    controller->frame_counter_read = true;
+
     // Read frame counters
     if (ws_pae_controller_nvm_frame_counter_read(&controller->frame_counters) >= 0) {
         bool updated = false;
@@ -610,6 +622,8 @@ static void ws_pae_controller_frame_counter_read(pae_controller_t *controller)
             if (controller->frame_counters.counter[index].set) {
                 // Increments frame counters
                 controller->frame_counters.counter[index].frame_counter += FRAME_COUNTER_INCREMENT;
+                controller->frame_counters.counter[index].stored_frame_counter =
+                    controller->frame_counters.counter[index].frame_counter;
 
                 tr_info("Read frame counter: index %i value %"PRIu32"", index, controller->frame_counters.counter[index].frame_counter);
 
@@ -620,7 +634,6 @@ static void ws_pae_controller_frame_counter_read(pae_controller_t *controller)
             // Writes incremented frame counters
             ws_pae_nvm_store_frame_counter_tlv_create(controller->pae_nvm_buffer, &controller->frame_counters);
             ws_pae_controller_nvm_frame_counter_write(controller->pae_nvm_buffer);
-            //ws_pae_controller_frame_counter_write(controller, &controller->frame_counters);
         }
     }
 }
@@ -630,6 +643,7 @@ static void ws_pae_controller_frame_counter_reset(frame_counters_t *frame_counte
     for (uint8_t index = 0; index < GTK_NUM; index++) {
         memset(frame_counters->counter[index].gtk, 0, GTK_LEN);
         frame_counters->counter[index].frame_counter = 0;
+        frame_counters->counter[index].stored_frame_counter = 0;
         frame_counters->counter[index].set = false;
     }
 }
@@ -689,9 +703,6 @@ int8_t ws_pae_controller_stop(protocol_interface_info_entry_t *interface_ptr)
         return -1;
     }
 
-    // Stores frame counter
-    ws_pae_controller_frame_counter_store(controller, false);
-
     // Removes network keys from PAE controller and MAC
     ws_pae_controller_nw_keys_remove(interface_ptr);
 
@@ -1241,18 +1252,25 @@ static void ws_pae_controller_frame_counter_store(pae_controller_t *entry, bool
             // If frame counter for the network key has already been stored
             if (entry->frame_counters.counter[i].set &&
                     memcmp(entry->nw_key[i].gtk, entry->frame_counters.counter[i].gtk, GTK_LEN) == 0) {
+
+                if (curr_frame_counter > entry->frame_counters.counter[i].frame_counter) {
+                    entry->frame_counters.counter[i].frame_counter = curr_frame_counter;
+                }
+                uint32_t frame_counter = entry->frame_counters.counter[i].frame_counter;
+
                 // If threshold check is disabled or frame counter has advanced for the threshold value, stores the new value
                 if (!use_threshold ||
-                        curr_frame_counter > entry->frame_counters.counter[i].frame_counter + FRAME_COUNTER_STORE_THRESHOLD) {
-                    entry->frame_counters.counter[i].frame_counter = curr_frame_counter;
+                        frame_counter > entry->frame_counters.counter[i].stored_frame_counter + FRAME_COUNTER_STORE_THRESHOLD) {
+                    entry->frame_counters.counter[i].stored_frame_counter = frame_counter;
                     update_needed = true;
-                    tr_debug("Stored updated frame counter: index %i value %"PRIu32"", i, curr_frame_counter);
+                    tr_debug("Stored updated frame counter: index %i value %"PRIu32"", i, frame_counter);
                 }
             } else {
                 // For new or modified network keys, stores the frame counter value
                 entry->frame_counters.counter[i].set = true;
                 memcpy(entry->frame_counters.counter[i].gtk, entry->nw_key[i].gtk, GTK_LEN);
                 entry->frame_counters.counter[i].frame_counter = curr_frame_counter;
+                entry->frame_counters.counter[i].stored_frame_counter = curr_frame_counter;
                 update_needed = true;
                 tr_debug("Stored new frame counter: index %i value %"PRIu32"", i, curr_frame_counter);
             }

source/Security/protocols/sec_prot_keys.h

@@ -102,7 +102,8 @@ typedef struct {
 // Frame counter data
 typedef struct {
     uint8_t gtk[GTK_LEN];                             /**< GTK of the frame counter */
-    uint32_t frame_counter;                           /**< Frame counter */
+    uint32_t frame_counter;                           /**< Current frame counter */
+    uint32_t stored_frame_counter;                    /**< Stored Frame counter */
     bool set : 1;                                     /**< Value has been set */
 } frame_counter_t;