NodeIDSelector: allocating only in the range [1, 125], unless the node explicitly requested higher node ID

libuavcan/include/uavcan/protocol/dynamic_node_id_server/node_id_selector.hpp

@@ -35,12 +35,12 @@ public:
     /**
      * Reutrns a default-constructed (invalid) node ID if a free one could not be found.
      */
-    NodeID findFreeNodeID(const NodeID preferred_node_id) const
+    NodeID findFreeNodeID(const NodeID preferred) const
     {
-        uint8_t candidate = preferred_node_id.isUnicast() ? preferred_node_id.get() : NodeID::Max;
+        uint8_t candidate = preferred.isUnicast() ? preferred.get() : NodeID::MaxRecommendedForRegularNodes;
 
         // Up
-        while (candidate <= NodeID::Max)
+        while (candidate <= NodeID::MaxRecommendedForRegularNodes)
         {
             if (!(owner_->*is_node_id_taken_)(candidate))
             {
@@ -49,7 +49,7 @@ public:
             candidate++;
         }
 
-        candidate = preferred_node_id.isUnicast() ? preferred_node_id.get() : NodeID::Max;
+        candidate = preferred.isUnicast() ? preferred.get() : NodeID::MaxRecommendedForRegularNodes;
         candidate--;        // This has been tested already
 
         // Down

libuavcan/include/uavcan/transport/transfer.hpp

@@ -129,6 +129,7 @@ class UAVCAN_EXPORT NodeID
 public:
     static const uint8_t BitLen = 7U;
     static const uint8_t Max = (1U << BitLen) - 1U;
+    static const uint8_t MaxRecommendedForRegularNodes = Max - 2;
     static const NodeID Broadcast;
 
     NodeID() : value_(ValueInvalid) { }

libuavcan/src/transport/uc_transfer.cpp

@@ -21,6 +21,7 @@ const uint8_t NodeID::ValueBroadcast;
 const uint8_t NodeID::ValueInvalid;
 const uint8_t NodeID::BitLen;
 const uint8_t NodeID::Max;
+const uint8_t NodeID::MaxRecommendedForRegularNodes;
 const NodeID NodeID::Broadcast(ValueBroadcast);
 
 /**