Add extension check for partition weight drop in parent selection (ARMmbed#1521)

Only drop partitions if security policy demands

Author: Mika Tervonen

source/6LoWPAN/Thread/thread_bootstrap.c

@@ -489,6 +489,14 @@ int thread_bootstrap_partition_process(protocol_interface_info_entry_t *cur, uin
         tr_debug("Heard a REED and I am a singleton - merge");
         return 2;
     }
+    /*Rule 0: If we are going to form Higher partition than heard we dont try to attach to lower ones
+     */
+    if (thread_extension_enabled(cur) &&
+        thread_info(cur)->thread_device_mode == THREAD_DEVICE_MODE_ROUTER &&
+        heard_partition_leader_data->weighting < thread_info(cur)->partition_weighting) {
+        return -2;
+    }
+
     //Rule 1: A non-singleton Thread Network Partition always has higher priority than a singleton Thread Network Partition
     if (heard_partition_routers > 1 && active_routers == 1) {
         tr_debug("Heard a nonsingleton and i am a singleton");

source/6LoWPAN/Thread/thread_discovery.c

@@ -559,7 +559,7 @@ static int thread_discovery_response_send(thread_discovery_class_t *class, threa
     *ptr++ = message_length;
     uint16_t discover_response_tlv = thread_discover_tlv_get(class->version, (linkConfiguration->securityPolicy & SECURITY_POLICY_NATIVE_COMMISSIONING_ALLOWED));
 
-    discover_response_tlv = thread_extension_discover_response_tlv_write(discover_response_tlv, class->version, thread_extension_security_policy_enabled(linkConfiguration->securityPolicy));
+    thread_extension_discover_response_tlv_write(&discover_response_tlv, class->version, linkConfiguration->securityPolicy);
 
     ptr = thread_meshcop_tlv_data_write_uint16(ptr, MESHCOP_TLV_DISCOVERY_RESPONSE, discover_response_tlv);
     ptr = thread_meshcop_tlv_data_write(ptr, MESHCOP_TLV_XPANID, 8, linkConfiguration->extented_pan_id);

source/6LoWPAN/Thread/thread_extension.c

@@ -568,8 +568,14 @@ void thread_extension_activate(protocol_interface_info_entry_t *cur)
     }
 }
 
-bool thread_extension_security_policy_enabled(uint8_t securityPolicy)
+bool thread_extension_enabled(protocol_interface_info_entry_t *cur)
 {
+    if (thread_info(cur)->version <= THREAD_PROTOCOL_VERSION) {
+        // Thread 1.1 version devices dont check the extension
+        return false;
+    }
+    uint16_t securityPolicy = thread_joiner_application_security_policy_get(cur->id);
+
     if (securityPolicy & SECURITY_POLICY_CCM_ENABLED) {
         return true;
     }
@@ -607,12 +613,13 @@ void thread_extension_discover_response_read(discovery_response_list_t *nwk_info
     discovery_add_info->ccm_supported = (discover_response_tlv >> 10) & 1;
 }
 
-uint16_t thread_extension_discover_response_tlv_write(uint16_t data, uint8_t version, bool extension_bit)
+void thread_extension_discover_response_tlv_write(uint16_t *data, uint8_t version, uint16_t securityPolicy)
 {
-    if (version == 3 && extension_bit) {
-        data |= (uint16_t) (1 << 10);
+
+    if (version == 3 && securityPolicy & SECURITY_POLICY_CCM_ENABLED) {
+        *data |= (uint16_t) (1 << 10);
     }
-    return data;
+    return;
 }
 
 #ifdef HAVE_THREAD_ROUTER

source/6LoWPAN/Thread/thread_extension.h

@@ -56,10 +56,10 @@ void thread_extension_mcast_subscrition_change(protocol_interface_info_entry_t *
 void thread_extension_address_registration_trigger(protocol_interface_info_entry_t *interface);
 void thread_extension_route_set(protocol_interface_info_entry_t *cur);
 void thread_extension_activate(protocol_interface_info_entry_t *cur);
-bool thread_extension_security_policy_enabled(uint8_t securityPolicy);
+bool thread_extension_enabled(protocol_interface_info_entry_t *cur);
 bool thread_extension_version_check(uint8_t version);
 void thread_extension_discover_response_read(struct discovery_response_list *nwk_info, uint16_t discover_response_tlv, uint8_t *data_ptr, uint16_t data_len);
-uint16_t thread_extension_discover_response_tlv_write(uint16_t data, uint8_t version, bool extension_bit);
+void thread_extension_discover_response_tlv_write(uint16_t *data, uint8_t version, uint16_t securityPolicy);
 #ifdef HAVE_THREAD_ROUTER
 int thread_extension_joiner_router_init(int8_t interface_id);
 bool thread_extension_joining_enabled(int8_t interface_id);
@@ -87,7 +87,7 @@ uint8_t *thread_extension_discover_response_write(protocol_interface_info_entry_
 #define thread_extension_mcast_subscrition_change(interface, group, added)
 #define thread_extension_route_set(cur)
 #define thread_extension_activate(cur)
-#define thread_extension_security_policy_enabled(securityPolicy) (false)
+#define thread_extension_enabled(cur) (false)
 #define thread_extension_version_check(version) (false)
 #define thread_extension_discover_response_read(nwk_info, discover_response_tlv, data_ptr, data_len)
 #define thread_extension_discover_response_tlv_write(data, version, extension_bit) (data)

source/6LoWPAN/Thread/thread_host_bootstrap.c

@@ -588,7 +588,10 @@ void thread_mle_parent_discover_receive_cb(int8_t interface_id, mle_message_t *m
                 }
             }
 
-            if (leaderData.weighting < thread_info(cur)->partition_weighting) {
+            if (thread_extension_enabled(cur) &&
+                thread_info(cur)->thread_device_mode == THREAD_DEVICE_MODE_ROUTER &&
+                leaderData.weighting < thread_info(cur)->partition_weighting) {
+                // Only applies to extensions and only routers that can form new partitions can ignore lower weight
                 tr_debug("Drop parent due weighting %d<%d", leaderData.weighting, thread_info(cur)->partition_weighting);
                 return;
             }
@@ -612,6 +615,7 @@ void thread_mle_parent_discover_receive_cb(int8_t interface_id, mle_message_t *m
                         (leaderData.weighting != currentWeighting)) {
                         int retVal = thread_bootstrap_partition_process(cur, connectivityTlv.activeRouters, &leaderData,NULL);
                         if (retVal > 0) {
+                            // New partition is Higher
                             scan_result = thread_info(cur)->thread_attach_scanned_parent;
                         }
                     }

source/6LoWPAN/Thread/thread_joiner_application.c

@@ -1031,6 +1031,16 @@ uint64_t thread_joiner_application_active_timestamp_get(int8_t interface_id)
     return this->configuration_ptr->timestamp;
 }
 
+uint8_t thread_joiner_application_security_policy_get(int8_t interface_id)
+{
+    thread_joiner_t *this = thread_joiner_find(interface_id);
+    if (!this) {
+        return 0;
+    }
+
+    return this->configuration_ptr->securityPolicy;
+}
+
 uint8_t *thread_joiner_application_random_mac_get(int8_t interface_id)
 {
     thread_joiner_t *this = thread_joiner_find(interface_id);

source/6LoWPAN/Thread/thread_joiner_application.h

@@ -67,6 +67,7 @@ void thread_joiner_application_deinit(int8_t interface_id);
 struct link_configuration *thread_joiner_application_get_config(int8_t interface_id);
 
 uint64_t thread_joiner_application_active_timestamp_get(int8_t interface_id);
+uint8_t thread_joiner_application_security_policy_get(int8_t interface_id);
 void thread_joiner_application_active_timestamp_set(int8_t interface_id, uint64_t timestamp);
 uint8_t *thread_joiner_application_active_config_tlv_list_get(uint8_t interface_id, uint16_t *length);
 

test/nanostack/unittest/stub/thread_extension_stub.c

@@ -124,6 +124,12 @@ void thread_extension_activate(protocol_interface_info_entry_t *cur)
 {
     (void)cur;
 }
+bool thread_extension_enabled(protocol_interface_info_entry_t *cur)
+{
+    (void)cur;
+    return false;
+}
+
 void thread_extension_route_set(protocol_interface_info_entry_t *cur)
 {
     (void)cur;

test/nanostack/unittest/stub/thread_joiner_application_stub.c

@@ -134,6 +134,11 @@ uint64_t thread_joiner_application_active_timestamp_get(int8_t interface_id)
 {
     return 0;
 }
+uint8_t thread_joiner_application_security_policy_get(int8_t interface_id)
+{
+    return 0;
+}
+
 int thread_joiner_application_domain_prefix_get(int8_t interface_id, uint8_t *options_ptr, uint8_t *domain_prefix_ptr, uint8_t *domain_prefix_len)
 {
     return 0;