TransferSender is now capable of broadcasting in passive mode; Frame::isValid() was modified to accept SFT broadcasts with zero SNID

libuavcan/include/uavcan/transport/dispatcher.hpp

@@ -115,6 +115,7 @@ public:
         : canio_(driver, allocator, sysclock)
         , sysclock_(sysclock)
         , outgoing_transfer_reg_(otr)
+        , self_node_id_(NodeID::Broadcast)  // Default
         , self_node_id_is_set_(false)
     { }
 

libuavcan/include/uavcan/transport/frame.hpp

@@ -50,7 +50,7 @@ public:
     {
         UAVCAN_ASSERT((transfer_type == TransferTypeMessageBroadcast) == dst_node_id.isBroadcast());
         UAVCAN_ASSERT(data_type_id.isValid());
-        UAVCAN_ASSERT(src_node_id != dst_node_id);
+        UAVCAN_ASSERT(src_node_id.isUnicast() ? (src_node_id != dst_node_id) : true);
         UAVCAN_ASSERT(frame_index <= MaxIndex);
     }
 

libuavcan/include/uavcan/transport/transfer_sender.hpp

@@ -25,6 +25,7 @@ class UAVCAN_EXPORT TransferSender
     const TransferCRC crc_base_;
     CanIOFlags flags_;
     uint8_t iface_mask_;
+    bool allow_broadcasting_in_passive_mode_;
 
     Dispatcher& dispatcher_;
 
@@ -46,6 +47,7 @@ public:
         , crc_base_(data_type.getSignature().toTransferCRC())
         , flags_(CanIOFlags(0))
         , iface_mask_(AllIfacesMask)
+        , allow_broadcasting_in_passive_mode_(false)
         , dispatcher_(dispatcher)
     { }
 
@@ -59,6 +61,13 @@ public:
         iface_mask_ = iface_mask;
     }
 
+    /**
+     * By default, this class will return an error on any attempt to publish a message while the
+     * dispatcher is configured in passive mode. This method allows to permanently enable sending
+     * broadcast transfers in passive mode for this class instance.
+     */
+    void allowBroadcastingInPassiveMode() { allow_broadcasting_in_passive_mode_ = true; }
+
     /**
      * Send with explicit Transfer ID.
      * Should be used only for service responses, where response TID should match request TID.