CBMC proof for vProcessGeneratedUDPPacket (#203)

* Add Proof

* Update

* Update the proof

* Update the proof

* Clean-up

* Clean-up v2

* Update freertos_api.c

* update stub

FreeRTOS-Plus/Test/CBMC/proofs/UDP/vProcessGeneratedUDPPacket/Makefile.json

@@ -0,0 +1,25 @@
+{
+  "ENTRY": "vProcessGeneratedUDPPacket",
+  "CBMCFLAGS":
+  [
+  ],
+  "OBJS":
+  [
+    "$(ENTRY)_harness.goto",
+    "$(FREERTOS)/../FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/FreeRTOS_UDP_IP.goto"
+  ],
+  "INSTFLAGS":
+  [
+  ],
+  "DEF":
+  [
+    "ipconfigSUPPORT_OUTGOING_PINGS=1",
+    "ipconfigBYTE_ORDER=pdFREERTOS_BIG_ENDIAN"
+  ],
+  "INC":
+  [
+    "$(FREERTOS)/../FreeRTOS-Plus/Test/CBMC/include",
+    "$(FREERTOS)/../FreeRTOS-Plus/Test/CBMC/proofs/utility",
+    "$(FREERTOS)/../FreeRTOS-Plus/Test/CBMC/stubs"
+  ]
+}

FreeRTOS-Plus/Test/CBMC/proofs/UDP/vProcessGeneratedUDPPacket/vProcessGeneratedUDPPacket_harness.c

@@ -0,0 +1,88 @@
+/* Standard includes. */
+#include <stdint.h>
+#include <stdio.h>
+
+/* FreeRTOS includes. */
+#include "FreeRTOS.h"
+#include "task.h"
+#include "queue.h"
+#include "list.h"
+#include "semphr.h"
+
+/* FreeRTOS+TCP includes. */
+#include "FreeRTOS_IP.h"
+#include "FreeRTOS_ARP.h"
+#include "FreeRTOS_UDP_IP.h"
+#include "FreeRTOS_IP_Private.h"
+
+/* Include the stubs for APIs. */
+#include "memory_assignments.c"
+#include "freertos_api.c"
+
+/* We do not need to calculate the actual checksum for the proof to be complete.
+ * Neither does the checksum matter for completeness. */
+uint16_t usGenerateChecksum( uint16_t usSum, const uint8_t * pucNextData, size_t uxByteCount )
+{
+	__CPROVER_assert( pucNextData != NULL, "Next data in GenerateChecksum cannot be NULL" );
+
+	uint16_t usChecksum;
+
+	/* Return any random value of checksum since it does not matter for CBMC checks. */
+	return usChecksum;
+}
+
+
+/* We do not need to calculate the actual checksum for the proof to be complete.
+ * Neither does the checksum matter for completeness. */
+uint16_t usGenerateProtocolChecksum( const uint8_t * const pucEthernetBuffer, size_t uxBufferLength, BaseType_t xOutgoingPacket )
+{
+	__CPROVER_assert( pucEthernetBuffer != NULL, "The Ethernet buffer cannot be NULL while generating Protocol Checksum" );
+	uint16_t usProtocolChecksum;
+
+	/* Return random value of checksum since it does not matter for CBMC checks. */
+	return usProtocolChecksum;
+}
+
+
+/* This function has been tested separately. Therefore, we assume that the implementation is correct. */
+void vARPRefreshCacheEntry( const MACAddress_t * pxMACAddress, const uint32_t ulIPAddress )
+{
+	/* pxMACAddress can be NULL or Non-NULL, no need to assert. */
+}
+
+
+/* This function has been tested separately. Therefore, we assume that the implementation is correct. */
+void vARPGenerateRequestPacket( NetworkBufferDescriptor_t * const pxNetworkBuffer )
+{
+	__CPROVER_assert( pxNetworkBuffer != NULL, "The network buffer cannot be NULL." );
+}
+
+
+/* This function has been tested separately. Therefore, we assume that the implementation is correct. */
+eARPLookupResult_t eARPGetCacheEntry( uint32_t *pulIPAddress, MACAddress_t * const pxMACAddress )
+{
+	__CPROVER_assert( pulIPAddress != NULL, "pulIPAddress cannot be NULL" );
+	__CPROVER_assert( pxMACAddress != NULL, "pxMACAddress cannot be NULL" );
+
+	eARPLookupResult_t eResult;
+	return eResult;
+}
+
+
+void harness()
+{
+	size_t xRequestedSizeBytes;
+
+	/* Assume that the size of packet must be greater than that of UDP-Packet and less than
+	 * that of the Ethernet Frame Size. */
+	__CPROVER_assume( xRequestedSizeBytes >= sizeof(UDPPacket_t) && xRequestedSizeBytes <= ipTOTAL_ETHERNET_FRAME_SIZE );
+
+	/* Second parameter is not used from CBMC's perspective. */
+	NetworkBufferDescriptor_t * const pxNetworkBuffer = pxGetNetworkBufferWithDescriptor( xRequestedSizeBytes, 0 );
+
+	/* The buffer cannot be NULL for the function call. */
+	__CPROVER_assume(pxNetworkBuffer != NULL);
+	__CPROVER_assume(pxNetworkBuffer->pucEthernetBuffer != NULL);
+
+	vProcessGeneratedUDPPacket( pxNetworkBuffer );
+}

FreeRTOS-Plus/Test/CBMC/stubs/freertos_api.c

@@ -377,3 +377,20 @@ const char * pcApplicationHostnameHook( void )
 }
 
 /****************************************************************/
+
+
+/****************************************************************
+ * Abstract xNetworkInterfaceOutput
+ * https://www.freertos.org/FreeRTOS-Plus/FreeRTOS_Plus_TCP/Embedded_Ethernet_Porting.html#xNetworkInterfaceOutput
+ ****************************************************************/
+BaseType_t xNetworkInterfaceOutput( NetworkBufferDescriptor_t * const pxNetworkBuffer, BaseType_t bReleaseAfterSend )
+{
+        __CPROVER_assert( pxNetworkBuffer != NULL, "The networkbuffer cannot be NULL" );
+
+	BaseType_t xReturn;
+
+        /* Return some random value. */
+        return xReturn;
+}
+
+/****************************************************************/