NetworkCompatChecker can tolerate no-response from CATS service. This allows nodes to not implement services at all while being UAVCAN compatible.

libuavcan/include/uavcan/protocol/network_compat_checker.hpp

@@ -40,6 +40,7 @@ class UAVCAN_EXPORT NetworkCompatibilityChecker : Noncopyable
     NodeIDMask nid_mask_checked_;
     NetworkCompatibilityCheckResult result_;
     DataTypeKind checking_dtkind_;
+    uint8_t num_failed_nodes_;
     bool last_cats_request_ok_;
 
     INode& getNode() { return ns_sub_.getNode(); }
@@ -63,11 +64,14 @@ public:
         : ns_sub_(node)
         , cats_cln_(node)
         , checking_dtkind_(DataTypeKindService)
+        , num_failed_nodes_(0)
         , last_cats_request_ok_(false)
     { }
 
     int execute();
 
+    uint8_t getNumFailedNodes() const { return num_failed_nodes_; }
+
     const NetworkCompatibilityCheckResult& getResult() const { return result_; }
 
     static int publishGlobalDiscoveryRequest(INode& node);

libuavcan/src/protocol/uc_network_compat_checker.cpp

@@ -132,21 +132,18 @@ int NetworkCompatibilityChecker::checkOneNode(NodeID nid)
 int NetworkCompatibilityChecker::checkNodes()
 {
     (void)nid_mask_checked_.reset();
-    while (true)
+    num_failed_nodes_ = 0;
+    result_ = NetworkCompatibilityCheckResult();
+
+    while (result_.isOk())
     {
         const NodeID nid = findNextUncheckedNode();
         if (nid.isValid())
         {
             UAVCAN_TRACE("NodeInitializer", "Checking nid=%i", int(nid.get()));
             const int res = checkOneNode(nid);
-            if (res < 0 || !result_.isOk())
-            {
-                return res;
-            }
-            if (cats_cln_.getResponseFailureCount() > 0)
-            {
-                return -cats_cln_.getResponseFailureCount();
-            }
+            num_failed_nodes_ += (res < 0) ? 1U : 0U;
+            UAVCAN_TRACE("NodeInitializer", "Checked nid=%i result=%i", int(nid.get()), res);
         }
         else { break; }
     }

libuavcan/test/protocol/network_compat_checker.cpp

@@ -22,12 +22,12 @@ static void registerTypes()
 }
 
 
-struct NodeInitializerRemoteContext
+struct NetworkCompatibilityCheckerRemoteContext
 {
     uavcan::NodeStatusProvider node_status_provider;
     uavcan::DataTypeInfoProvider data_type_info_provider;
 
-    NodeInitializerRemoteContext(uavcan::INode& node)
+    NetworkCompatibilityCheckerRemoteContext(uavcan::INode& node)
         : node_status_provider(node)
         , data_type_info_provider(node)
     {
@@ -71,7 +71,7 @@ TEST(NetworkCompatibilityChecker, Success)
 {
     registerTypes();
     InterlinkedTestNodesWithSysClock nodes;
-    NodeInitializerRemoteContext remote(nodes.b);
+    NetworkCompatibilityCheckerRemoteContext remote(nodes.b);
     remote.start();
 
     BackgroundSpinner bgspinner(nodes.b, nodes.a);
@@ -89,13 +89,18 @@ TEST(NetworkCompatibilityChecker, RequestTimeout)
 {
     registerTypes();
     InterlinkedTestNodesWithSysClock nodes;
-    NodeInitializerRemoteContext remote(nodes.b);
+    NetworkCompatibilityCheckerRemoteContext remote(nodes.b);
     remote.start();
 
     ASSERT_LE(0, uavcan::NetworkCompatibilityChecker::publishGlobalDiscoveryRequest(nodes.a));
 
     uavcan::NetworkCompatibilityChecker ni(nodes.a);
-    ASSERT_GT(0, ni.execute());            // There is no background spinner, so CATS request will time out
+    // There is no background spinner, so CATS request will time out
+    // Despite the time out, the checker will not report failure
+    ASSERT_EQ(0, ni.execute());
+
+    // The one (and only) node has failed
+    ASSERT_EQ(1, ni.getNumFailedNodes());
 }
 
 
@@ -103,7 +108,7 @@ TEST(NetworkCompatibilityChecker, NodeIDCollision)
 {
     registerTypes();
     InterlinkedTestNodesWithSysClock nodes(8, 8);   // Same NID
-    NodeInitializerRemoteContext remote(nodes.b);
+    NetworkCompatibilityCheckerRemoteContext remote(nodes.b);
     remote.start();
 
     BackgroundSpinner bgspinner(nodes.b, nodes.a);