Fix nasa#19, Clarify PDU size limits

config/default_cf_tblstruct.h

@@ -48,9 +48,9 @@ typedef struct CF_ConfigTable
 
     CF_ChannelConfig_t chan[CF_NUM_CHANNELS]; /**< \brief Channel configuration */
 
-    uint16 outgoing_file_chunk_size;    /**< maximum size of outgoing file data PDUs - must be
-                                         *   smaller than file data character array */
-    char tmp_dir[CF_FILENAME_MAX_PATH]; /**< directory to put temp files */
+    uint16 outgoing_file_chunk_size;    /**< \brief maximum size of outgoing file data chunk in a PDU.
+                                         *   Limited by CF_MAX_PDU_SIZE minus the PDU header(s) */
+    char tmp_dir[CF_FILENAME_MAX_PATH]; /**< \brief directory to put temp files */
 } CF_ConfigTable_t;
 
 #endif

fsw/src/cf_cfdp_pdu.h

@@ -369,11 +369,13 @@ typedef struct CF_CFDP_PduFileDataHeader
 } CF_CFDP_PduFileDataHeader_t;
 
 /**
- * @brief PDU file data content
+ * @brief
+ * PDU file data content typedef for limit checking outgoing_file_chunk_size
+ * table value and set parameter command.
  *
- * To serve as a sanity check, this should accommodate the largest data block possible.
- * In that light, it should be sized based on the minimum encoded header size, rather than
- * the maximum, as that case leaves the most space for data.
+ * This definition allows for the largest data block possible, as CF_MAX_PDU_SIZE -
+ * the minimum possible header size.  In practice the outgoing file chunk size is limited by
+ * whichever is smaller; the remaining data, remaining space in the packet, and outgoing_file_chunk_size.
  */
 typedef struct CF_CFDP_PduFileDataContent
 {

fsw/src/cf_cfdp_types.h

@@ -410,24 +410,16 @@ typedef struct CF_Channel
     uint8 tick_type;
 } CF_Channel_t;
 
-/* NOTE: the use of CF_CFDP_PduHeader_t below is correct, but the CF_PduRecvMsg_t and CF_PduSendMsg_t
- * structures are both longer than these definitions. They are always backed by a buffer
- * of size CF_MAX_PDU_SIZE */
-
 /**
  * @brief CF engine output state
  *
  * Keeps the state of the current output PDU in the CF engine
  */
 typedef struct CF_Output
 {
-    CFE_SB_Buffer_t * msg;    /**< \brief Binary message to be sent to underlying transport */
-    CF_EncoderState_t encode; /**< \brief Encoding state (while building message) */
-
-    /**
-     * \brief Temporary R/W buffer for holding output PDUs while working with them
-     */
-    CF_Logical_PduBuffer_t tx_pdudata;
+    CFE_SB_Buffer_t       *msg;        /**< \brief Binary message to be sent to underlying transport */
+    CF_EncoderState_t      encode;     /**< \brief Encoding state (while building message) */
+    CF_Logical_PduBuffer_t tx_pdudata; /**< \brief Tx PDU logical values */
 } CF_Output_t;
 
 /**
@@ -437,13 +429,9 @@ typedef struct CF_Output
  */
 typedef struct CF_Input
 {
-    CFE_SB_Buffer_t * msg;    /**< \brief Binary message received from underlying transport */
-    CF_DecoderState_t decode; /**< \brief Decoding state (while interpreting message) */
-
-    /**
-     * \brief Temporary R/W buffer for holding input PDUs while working with them
-     */
-    CF_Logical_PduBuffer_t rx_pdudata;
+    CFE_SB_Buffer_t       *msg;        /**< \brief Binary message received from underlying transport */
+    CF_DecoderState_t      decode;     /**< \brief Decoding state (while interpreting message) */
+    CF_Logical_PduBuffer_t rx_pdudata; /**< \brief Rx PDU logical values */
 } CF_Input_t;
 
 /**