Merge pull request ARMmbed#1978 from ARMmbed/IOTTHD-3219

Fix issues found by Coverity

Author: Arto Kinnunen

source/6LoWPAN/Thread/thread_extension_bbr.c

@@ -1087,7 +1087,7 @@ static int thread_border_router_pbbr_nw_data_register(thread_pbbr_t *this)
         return -1;
     }
 
-    if (!addr_is_ipv6_unspecified(this->domain_prefix)) {
+    if (memcmp(this->domain_prefix, ADDR_UNSPECIFIED, 8) != 0) {
         thread_border_router_info_t br_info = {0};
         br_info.P_on_mesh = true;
         br_info.stableData = true;
@@ -1443,7 +1443,7 @@ int thread_extension_bbr_prefix_set(int8_t interface_id, uint8_t *prefix)
         return 0;
     }
 
-    if (!addr_is_ipv6_unspecified(this->domain_prefix)) {
+    if (memcmp(this->domain_prefix, ADDR_UNSPECIFIED, 8) != 0) {
         thread_border_router_info_t br_info = {0};
         br_info.P_on_mesh = true;
         br_info.stableData = true;

source/6LoWPAN/Thread/thread_host_bootstrap.c

@@ -470,8 +470,9 @@ static bool thread_host_prefer_parent_response(protocol_interface_info_entry_t *
 {
     (void) connectivity;
     (void) cur;
+    bool cur_version = thread_extension_version_check(thread_info(cur)->version);
 
-    if (!thread_extension_version_check(thread_info(cur)->version)) {
+    if (!cur_version) {
         return false;
     }
 

source/6LoWPAN/Thread/thread_management_if.c

@@ -1370,14 +1370,16 @@ int thread_management_network_certificate_set(int8_t interface_id, const unsigne
 {
 #ifdef HAVE_THREAD
     protocol_interface_info_entry_t *cur;
+    int ret_val;
 
     cur = protocol_stack_interface_info_get_by_id(interface_id);
     if (!cur) {
         tr_debug("invalid interface id");
         return -1;
     }
 
-    if (0 > thread_extension_bootstrap_network_certificate_set(cur, network_certificate_ptr, network_certificate_len)) {
+    ret_val = thread_extension_bootstrap_network_certificate_set(cur, network_certificate_ptr, network_certificate_len);
+    if (0 > ret_val) {
         return -1;
     }