Sync with +TCP amazon-FreeRTOS (#158)

* DNS.c commit

* IP.c commit

* Add various source & header files

FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/FreeRTOS_DNS.c

@@ -112,6 +112,9 @@ type. */
 	#endif
 #endif
 
+/* Define the ASCII value of '.' (Period/Full-stop). */
+#define ASCII_BASELINE_DOT						46U
+
 /*
  * Create a socket and bind it to the standard DNS port number.  Return the
  * the created socket - or NULL if the socket could not be created or bound.
@@ -217,8 +220,7 @@ static uint32_t prvGetHostByName( const char *pcHostName,
 
 	static DNSCacheRow_t xDNSCache[ ipconfigDNS_CACHE_ENTRIES ];
 
-	/* MISRA c 2012 rule 8.7: Below function may be used by 
+	/* Utility function: Clear DNS cache by calling this function. */
-	external callees as well			        */
 	void FreeRTOS_dnsclear( void )
 	{
 		( void ) memset( xDNSCache, 0x0, sizeof( xDNSCache ) );
@@ -327,9 +329,6 @@ typedef struct xDNSAnswerRecord DNSAnswerRecord_t;
 /*-----------------------------------------------------------*/
 
 #if( ipconfigUSE_DNS_CACHE == 1 )
-
-	/* MISRA c 2012 rule 8.7: Below function may be used by 
-	external callees as well			        */
 	uint32_t FreeRTOS_dnslookup( const char *pcHostName )
 	{
 	uint32_t ulIPAddress = 0UL;
@@ -501,8 +500,6 @@ typedef struct xDNSAnswerRecord DNSAnswerRecord_t;
 /*-----------------------------------------------------------*/
 
 #if( ipconfigDNS_USE_CALLBACKS == 0 )
-	/* MISRA c 2012 rule 8.7 ralxed since this function can
-	be called from external sources as well             */
 	uint32_t FreeRTOS_gethostbyname( const char *pcHostName )
 	{
 		return prvPrepareLookup( pcHostName );
@@ -532,8 +529,33 @@ TickType_t uxReadTimeOut_ticks = ipconfigDNS_RECEIVE_BLOCK_TIME_TICKS;
  as gethostbyname() may be called from different threads */
 BaseType_t xHasRandom = pdFALSE;
 TickType_t uxIdentifier = 0U;
+#if( ipconfigUSE_DNS_CACHE != 0 )
+	BaseType_t xLengthOk = pdFALSE;
+#endif
 
+	#if( ipconfigUSE_DNS_CACHE != 0 )
+	{
 		if( pcHostName != NULL )
+		{
+		size_t xLength = strlen( pcHostName ) + 1;
+
+			if( xLength <= ipconfigDNS_CACHE_NAME_LENGTH )
+			{
+				/* The name is not too long. */
+				xLengthOk = pdTRUE;
+			}
+			else
+			{
+				FreeRTOS_printf( ( "prvPrepareLookup: name is too long ( %lu > %lu )\n",
+								   ( unsigned long ) xLength,
+								   ( unsigned long ) ipconfigDNS_CACHE_NAME_LENGTH ) );
+			}
+		}
+	}
+	if( ( pcHostName != NULL ) && ( xLengthOk != pdFALSE ) )
+	#else
+	if( pcHostName != NULL )
+	#endif	/* ( ipconfigUSE_DNS_CACHE != 0 ) */
 	{
 		/* If the supplied hostname is IP address, convert it to uint32_t
 		and return. */
@@ -647,7 +669,7 @@ TickType_t uxWriteTimeOut_ticks = ipconfigDNS_SEND_BLOCK_TIME_TICKS;
 	if( xDNSSocket != NULL )
 	{
 		/* Ideally we should check for the return value. But since we are passing
-		correect parameters, and xDNSSocket is != NULL, the return value is 
+		correct parameters, and xDNSSocket is != NULL, the return value is 
 		going to be '0' i.e. success. Thus, return value is discarded */
 		( void ) FreeRTOS_setsockopt( xDNSSocket, 0, FREERTOS_SO_SNDTIMEO, &( uxWriteTimeOut_ticks ), sizeof( TickType_t ) );
 		( void ) FreeRTOS_setsockopt( xDNSSocket, 0, FREERTOS_SO_RCVTIMEO, &( uxReadTimeOut_ticks ),  sizeof( TickType_t ) );
@@ -785,10 +807,12 @@ static const DNSMessage_t xDefaultPartDNSHeader =
 	0                  /* No additional authorities. */
 };
 
-	/* Copy in the const part of the header. */
+	/* Copy in the const part of the header. Intentionally using different
+	 * pointers with memcpy() to put the information in to correct place. */
 	( void ) memcpy( pucUDPPayloadBuffer, &( xDefaultPartDNSHeader ), sizeof( xDefaultPartDNSHeader ) );
 
-	/* Write in a unique identifier. */
+	/* Write in a unique identifier. Cast the Payload Buffer to DNSMessage_t
+	 * to easily access fields of the DNS Message. */
 	pxDNSMessageHeader = ipPOINTER_CAST( DNSMessage_t *, pucUDPPayloadBuffer );
 	pxDNSMessageHeader->usIdentifier = ( uint16_t ) uxIdentifier;
 
@@ -815,9 +839,7 @@ static const DNSMessage_t xDefaultPartDNSHeader =
 	{
 		pucByte++;
 
-		/* MISRA c 2012 rule 10.4 relaxed for increased readability.
+		while( ( *pucByte != ( uint8_t ) 0U ) && ( *pucByte != ( uint8_t ) ASCII_BASELINE_DOT ) )
-		Not writing 46U instead of '.' */
-		while( ( *pucByte != ( uint8_t ) 0U ) && ( *pucByte != ( uint8_t ) '.' ) )
 		{
 			pucByte++;
 		}
@@ -830,7 +852,8 @@ static const DNSMessage_t xDefaultPartDNSHeader =
 		pucStart = pucByte;
 	} while( *pucByte != ( uint8_t ) 0U );
 
-	/* Finish off the record. */
+	/* Finish off the record. Cast the record onto DNSTail_t stucture to easily
+	 * access the fields of the DNS Message. */
 	pxTail = ipPOINTER_CAST(DNSTail_t *, &( pucByte[ 1 ] ) );
 
 	#if defined( _lint ) || defined( __COVERITY__ )
@@ -1012,9 +1035,6 @@ when ipconfigDNS_USE_CALLBACKS == 1
 when ipconfigUSE_LLMNR == 1
 for testing purposes, by the module iot_test_freertos_tcp.c
 */
-
-/* MISRA c 2012 rule 8.7: Function below may be used by external
-callees as well. */
 uint32_t ulDNSHandlePacket( const NetworkBufferDescriptor_t *pxNetworkBuffer )
 {
 DNSMessage_t *pxDNSMessageHeader;
@@ -1076,6 +1096,8 @@ uint8_t *pucByte;
 size_t uxSourceBytesRemaining;
 uint16_t x, usDataLength, usQuestions;
 uint16_t usType = 0U;
+BaseType_t xReturn = pdTRUE;
+
 #if( ipconfigUSE_LLMNR == 1 )
 	uint16_t usClass = 0U;
 #endif
@@ -1087,13 +1109,14 @@ uint16_t usType = 0U;
 	/* Ensure that the buffer is of at least minimal DNS message length. */
 	if( uxBufferLength < sizeof( DNSMessage_t ) )
 	{
-		return dnsPARSE_ERROR;
+		xReturn = pdFALSE;
 	}
-
+	else
+	{
 		uxSourceBytesRemaining = uxBufferLength;
 
-	/* Parse the DNS message header.
+		/* Parse the DNS message header. Map the byte stream onto a structure 
-	MISRA c 2012 rule 11.3 relaxed to make byte by byte traversal easier */
+		 * for easier access. */
 		pxDNSMessageHeader = ipPOINTER_CAST( DNSMessage_t *, pucUDPPayloadBuffer );
 
 		/* Introduce a do {} while (0) to allow the use of breaks. */
@@ -1131,7 +1154,8 @@ uint16_t usType = 0U;
 					/* Check for a malformed response. */
 					if( uxResult == 0U )
 					{
-					return dnsPARSE_ERROR;
+						xReturn = pdFALSE;
+						break;
 					}
 					uxBytesRead += uxResult;
 					pucByte = &( pucByte[ uxResult ] );
@@ -1147,7 +1171,8 @@ uint16_t usType = 0U;
 					/* Check for a malformed response. */
 					if( uxResult == 0U )
 					{
-					return dnsPARSE_ERROR;
+						xReturn = pdFALSE;
+						break;
 					}
 					uxBytesRead += uxResult;
 					pucByte = &( pucByte[ uxResult ] );
@@ -1171,18 +1196,26 @@ uint16_t usType = 0U;
 				}
 				else
 				{
-				return dnsPARSE_ERROR;
+					xReturn = pdFALSE;
+					break;
 				}
 			}
 
+			if( xReturn == pdFALSE )
+			{
+				/* No need to proceed. Break out of the do-while loop. */
+				break;
+			}
+
 			/* Search through the answer records. */
 			pxDNSMessageHeader->usAnswers = FreeRTOS_ntohs( pxDNSMessageHeader->usAnswers );
 
 			if( ( pxDNSMessageHeader->usFlags & dnsRX_FLAGS_MASK ) == dnsEXPECTED_RX_FLAGS )
 			{
 			const uint16_t usCount = ( uint16_t ) ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY;
+			uint16_t usNumARecordsStored = 0;
 	
-			for( x = 0U; ( x < pxDNSMessageHeader->usAnswers ) && ( x < usCount ); x++ )
+				for( x = 0U; ( x < pxDNSMessageHeader->usAnswers ) && ( usNumARecordsStored < usCount ); x++ )
 				{
 				BaseType_t xDoAccept;
 	
@@ -1192,7 +1225,8 @@ uint16_t usType = 0U;
 					/* Check for a malformed response. */
 					if( uxResult == 0U )
 					{
-					return dnsPARSE_ERROR;
+						xReturn = pdFALSE;
+						break;
 					}
 
 					uxBytesRead += uxResult;
@@ -1203,7 +1237,8 @@ uint16_t usType = 0U;
 					is this an A record? */
 					if( uxSourceBytesRemaining < sizeof( uint16_t ) )
 					{
-					return dnsPARSE_ERROR;
+						xReturn = pdFALSE;
+						break;
 					}
 					usType = usChar2u16( pucByte );
 
@@ -1223,20 +1258,19 @@ uint16_t usType = 0U;
 						/* Unknown host type. */
 						xDoAccept = pdFALSE;
 					}
+
 					if( xDoAccept != pdFALSE )
 					{
 						/* This is the required record type and is of sufficient size. */
-					/* MISRA c 2012 rule 11.3 relaxed. pucByte is used for byte-by-byte
+						/* Mapping pucByte to a DNSAnswerRecord allows easy access of the
-					traversal. */
+						 * fields of the structure. */
 						pxDNSAnswerRecord = ipPOINTER_CAST( DNSAnswerRecord_t *, pucByte );
 
 						/* Sanity check the data length of an IPv4 answer. */
 						if( FreeRTOS_ntohs( pxDNSAnswerRecord->usDataLength ) == ( uint16_t ) sizeof( uint32_t ) )
 						{
-						/* Copy the IP address out of the record. */
+							/* Copy the IP address out of the record. Using different pointers
-						/* MISRA c 2012 rule 21.15 relaxed here since this seems
+							 * to copy only the portion we want is intentional here. */
-						to be the least cumbersome way to get the IP address
-						from the record. */
 							( void ) memcpy( &( ulIPAddress ),
 											 &( pucByte[ sizeof( DNSAnswerRecord_t ) ] ),
 											 sizeof( uint32_t ) );
@@ -1254,18 +1288,22 @@ uint16_t usType = 0U;
 							#endif	/* ipconfigDNS_USE_CALLBACKS == 1 */
 							#if( ipconfigUSE_DNS_CACHE == 1 )
 							{
+							char cBuffer[ 16 ];
+
 								/* The reply will only be stored in the DNS cache when the
 								request was issued by this device. */
 								if( xDoStore != pdFALSE )
 								{
 									( void ) prvProcessDNSCache( pcName, &ulIPAddress, pxDNSAnswerRecord->ulTTL, pdFALSE );
+									usNumARecordsStored++;    /* Track # of A records stored */
 								}
 
+								FreeRTOS_inet_ntop( FREERTOS_AF_INET, ( const void * ) &( ulIPAddress ), cBuffer, sizeof( cBuffer ) );
 								/* Show what has happened. */
-							FreeRTOS_printf( ( "DNS[0x%04lX]: The answer to '%s' (%lxip) will%s be stored\n",
+								FreeRTOS_printf( ( "DNS[0x%04lX]: The answer to '%s' (%s) will%s be stored\n",
 												   ( UBaseType_t ) pxDNSMessageHeader->usIdentifier,
 												   pcName,
-											   ( UBaseType_t ) FreeRTOS_ntohl( ulIPAddress ),
+												   cBuffer,
 												   ( xDoStore != 0 ) ? "" : " NOT" ) );
 							}
 							#endif /* ipconfigUSE_DNS_CACHE */
@@ -1278,9 +1316,7 @@ uint16_t usType = 0U;
 					{
 						/* It's not an A record, so skip it. Get the header location
 						and then jump over the header. */
-
+						/* Cast the response to DNSAnswerRecord for easy access to fields of the DNS response. */
-					/* MISRA c 2012 rule 11.3 relaxed as pucByte is being used in
-					various places to point to various parts of the DNS records */
 						pxDNSAnswerRecord = ipPOINTER_CAST( DNSAnswerRecord_t *, pucByte );
 
 						pucByte = &( pucByte[ sizeof( DNSAnswerRecord_t ) ] );
@@ -1298,7 +1334,8 @@ uint16_t usType = 0U;
 						else
 						{
 							/* Malformed response. */
-						return dnsPARSE_ERROR;
+							xReturn = pdFALSE;
+							break;
 						}
 					}
 					else
@@ -1391,12 +1428,23 @@ uint16_t usType = 0U;
 #endif /* ipconfigUSE_LLMNR == 1 */
 			( void ) uxBytesRead;
 		} while( ipFALSE_BOOL );
+	}
 
-	if( xExpected == pdFALSE )
+	if( xReturn == pdFALSE )
+	{
+		/* There was an error while parsing the DNS response. Return error code. */
+		ulIPAddress = dnsPARSE_ERROR;
+	}
+	else if( xExpected == pdFALSE )
 	{
 		/* Do not return a valid IP-address in case the reply was not expected. */
 		ulIPAddress = 0UL;
 	}
+	else
+	{
+		/* The IP-address found will be returned. */
+	}
+
 	#if( ipconfigUSE_DNS_CACHE == 1 ) || ( ipconfigDNS_USE_CALLBACKS == 1 )
 	( void ) xDoStore;
 	#endif
@@ -1567,9 +1615,11 @@ BaseType_t xReturn;
 	xSocket = FreeRTOS_socket( FREERTOS_AF_INET, FREERTOS_SOCK_DGRAM, FREERTOS_IPPROTO_UDP );
 	if( ( xSocket == FREERTOS_INVALID_SOCKET ) || ( xSocket == NULL ) )
 	{
-		return NULL;
+		/* There was an error, return NULL. */
+		xSocket = NULL;
 	}
-
+	else
+	{
 		/* Auto bind the port. */
 		xAddress.sin_port = 0U;
 		xReturn = FreeRTOS_bind( xSocket, &xAddress, sizeof( xAddress ) );
@@ -1584,6 +1634,7 @@ BaseType_t xReturn;
 		{
 			/* The send and receive timeouts will be set later on. */
 		}
+	}
 
 	return xSocket;
 }
@@ -1651,9 +1702,6 @@ BaseType_t xReturn;
 	uint32_t ulIPAddressIndex = 0;
 	static BaseType_t xFreeEntry = 0;
 
-		/* MISRA advisory rule 1.2 Relaxed in case of 
-		configASSERT as using __FUNCTION__ makes 
-		debugging easier 			   */
 		configASSERT( ( pcName != NULL ) );
 
 		/* For each entry in the DNS cache table. */
@@ -1736,7 +1784,7 @@ BaseType_t xReturn;
 					xDNSCache[ xFreeEntry ].ucCurrentIPAddress = 0;
 
 					/* Initialize all remaining IP addresses in this entry to 0 */
-					memset( &xDNSCache[ xFreeEntry ].ulIPAddresses[ 1 ],
+					( void ) memset( &xDNSCache[ xFreeEntry ].ulIPAddresses[ 1 ],
 							0,
 							sizeof( xDNSCache[ xFreeEntry ].ulIPAddresses[ 1 ] ) *
 								( ( uint32_t ) ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY - 1U ) );

FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/FreeRTOS_IP.c

@@ -798,7 +798,7 @@ const TickType_t xDontBlock = ( TickType_t ) 0;
 	iptraceNETWORK_DOWN();
 }
 /*-----------------------------------------------------------*/
-
+/* Utility function. Process Network Down event from ISR. */
 BaseType_t FreeRTOS_NetworkDownFromISR( void )
 {
 static const IPStackEvent_t xNetworkDownEvent = { eNetworkDownEvent, NULL };
@@ -1288,6 +1288,7 @@ eFrameProcessingResult_t eConsiderFrameForProcessing( const uint8_t * const pucE
 eFrameProcessingResult_t eReturn;
 const EthernetHeader_t *pxEthernetHeader;
 
+	/* Map the buffer onto Ethernet Header struct for easy access to fields. */
 	pxEthernetHeader = ipPOINTER_CAST( const EthernetHeader_t *, pucEthernetBuffer );
 
 	if( memcmp( ipLOCAL_MAC_ADDRESS, pxEthernetHeader->xDestinationAddress.ucBytes, sizeof( MACAddress_t ) ) == 0 )
@@ -1427,6 +1428,8 @@ eFrameProcessingResult_t eReturned = eReleaseBuffer;
 	if( pxNetworkBuffer->xDataLength >= sizeof( EthernetHeader_t ) )
 	{
 		eReturned = ipCONSIDER_FRAME_FOR_PROCESSING( pxNetworkBuffer->pucEthernetBuffer );
+
+		/* Map the buffer onto the Ethernet Header struct for easy access to the fields. */
 		pxEthernetHeader = ipPOINTER_CAST( const EthernetHeader_t *, pxNetworkBuffer->pucEthernetBuffer );
 
 		/* The condition "eReturned == eProcessBuffer" must be true. */
@@ -1688,9 +1691,10 @@ uint8_t ucProtocol;
 	if( ( uxHeaderLength > ( pxNetworkBuffer->xDataLength - ipSIZE_OF_ETH_HEADER ) ) ||
 		( uxHeaderLength < ipSIZE_OF_IPv4_HEADER ) )
 	{
-		return eReleaseBuffer;
+		eReturn = eReleaseBuffer;
 	}
-
+	else
+	{
 		ucProtocol = pxIPPacket->xIPHeader.ucProtocol;
 		/* Check if the IP headers are acceptable and if it has our destination. */
 		eReturn = prvAllowIPPacket( pxIPPacket, pxNetworkBuffer, uxHeaderLength );
@@ -1725,11 +1729,13 @@ uint8_t ucProtocol;
 				{
 					/* 'ipconfigIP_PASS_PACKETS_WITH_IP_OPTIONS' is not set, so packets carrying
 					IP-options will be dropped. */
-				return eReleaseBuffer;
+					eReturn = eReleaseBuffer;
 				}
 				#endif
 			}
 
+			if( eReturn != eReleaseBuffer )
+			{
 				/* Add the IP and MAC addresses to the ARP table if they are not
 				already there - otherwise refresh the age of the existing
 				entry. */
@@ -1754,6 +1760,8 @@ uint8_t ucProtocol;
 						{
 							if( pxNetworkBuffer->xDataLength >= sizeof( ICMPPacket_t ) )
 							{
+								/* Map the buffer onto a ICMP-Packet struct to easily access the
+								 * fields of ICMP packet. */
 								ICMPPacket_t *pxICMPPacket = ipPOINTER_CAST( ICMPPacket_t *, pxNetworkBuffer->pucEthernetBuffer );
 								if( pxIPHeader->ulDestinationIPAddress == *ipLOCAL_IP_ADDRESS_POINTER )
 								{
@@ -1771,6 +1779,9 @@ uint8_t ucProtocol;
 					case ipPROTOCOL_UDP :
 						{
 						/* The IP packet contained a UDP frame. */
+
+						/* Map the buffer onto a UDP-Packet struct to easily access the
+						 * fields of UDP packet. */
 						const UDPPacket_t *pxUDPPacket = ipPOINTER_CAST( const UDPPacket_t *, pxNetworkBuffer->pucEthernetBuffer );
 						uint16_t usLength;
 
@@ -1840,6 +1851,8 @@ uint8_t ucProtocol;
 						break;
 				}
 			}
+		}
+	}
 
 	return eReturn;
 }
@@ -1995,7 +2008,8 @@ uint8_t ucProtocol;
 				break;
 			}
 
-			/* Parse the packet length. */
+			/* Map the buffer onto a IP-Packet struct to easily access the
+			 * fields of the IP packet. */
 			pxIPPacket = ipPOINTER_CAST( const IPPacket_t *, pucEthernetBuffer );
 
 			ucVersionHeaderLength = pxIPPacket->xIPHeader.ucVersionHeaderLength;
@@ -2028,11 +2042,13 @@ uint8_t ucProtocol;
 			/* Identify the next protocol. */
 			ucProtocol = pxIPPacket->xIPHeader.ucProtocol;
 
-			/* N.B., if this IP packet header includes Options, then the following
+			/* If this IP packet header includes Options, then the following
 			assignment results in a pointer into the protocol packet with the Ethernet
 			and IP headers incorrectly aligned. However, either way, the "third"
 			protocol (Layer 3 or 4) header will be aligned, which is the convenience
 			of this calculation. */
+			/* Map the Buffer onto the Protocol Packet struct for easy access to the
+			 * struct fields. */
 			pxProtPack = ipPOINTER_CAST( ProtocolPacket_t *, &( pucEthernetBuffer[ uxIPHeaderLength - ipSIZE_OF_IPv4_HEADER ] ) );
 
 			/* Switch on the Layer 3/4 protocol. */
@@ -2104,12 +2120,16 @@ uint16_t ucVersionHeaderLength;
 
 BaseType_t location = 0;
 
+	/* Introduce a do-while loop to allow use of break statements.
+	 * Note: MISRA prohibits use of 'goto', thus replaced with breaks. */
+	do
+	{
 		/* Check for minimum packet size. */
 		if( uxBufferLength < sizeof( IPPacket_t ) )
 		{
 			usChecksum = ipINVALID_LENGTH;
 			location = 1;
-	 	goto error_exit;
+			break;
 		}
 
 		/* Parse the packet length. */
@@ -2126,7 +2146,7 @@ BaseType_t location = 0;
 		{
 			usChecksum = ipINVALID_LENGTH;
 			location = 2;
-	 	goto error_exit;
+			break;
 		}
 		usLength = pxIPPacket->xIPHeader.usLength;
 		usLength = FreeRTOS_ntohs( usLength );
@@ -2134,7 +2154,7 @@ BaseType_t location = 0;
 		{
 			usChecksum = ipINVALID_LENGTH;
 			location = 3;
-	 	goto error_exit;
+			break;
 		}
 
 		/* Identify the next protocol. */
@@ -2154,7 +2174,7 @@ BaseType_t location = 0;
 			{
 				usChecksum = ipINVALID_LENGTH;
 				location = 4;
-			goto error_exit;
+				break;
 			}
 
 			pusChecksum = ( uint16_t * ) ( &( pxProtPack->xUDPPacket.xUDPHeader.usChecksum ) );
@@ -2170,7 +2190,7 @@ BaseType_t location = 0;
 			{
 				usChecksum = ipINVALID_LENGTH;
 				location = 5;
-			goto error_exit;
+				break;
 			}
 
 			pusChecksum = ( uint16_t * ) ( &( pxProtPack->xTCPPacket.xTCPHeader.usChecksum ) );
@@ -2187,7 +2207,7 @@ BaseType_t location = 0;
 			{
 				usChecksum = ipINVALID_LENGTH;
 				location = 6;
-			goto error_exit;
+				break;
 			}
 
 			pusChecksum = ( uint16_t * ) ( &( pxProtPack->xICMPPacket.xICMPHeader.usChecksum ) );
@@ -2209,7 +2229,7 @@ BaseType_t location = 0;
 			/* Unhandled protocol, other than ICMP, IGMP, UDP, or TCP. */
 			usChecksum = ipUNHANDLED_PROTOCOL;
 			location = 7;
-		goto error_exit;
+			break;
 		}
 
 		/* The protocol and checksum field have been identified. Check the direction
@@ -2247,7 +2267,7 @@ BaseType_t location = 0;
 			}
 			#endif
 			location = 8;
-		goto error_exit;
+			break;
 		}
 		else
 		{
@@ -2274,7 +2294,7 @@ BaseType_t location = 0;
 			format/length */
 			usChecksum = ipINVALID_LENGTH;
 			location = 9;
-		goto error_exit;
+			break;
 		}
 		if( ucProtocol <= ( uint8_t ) ipPROTOCOL_IGMP )
 		{
@@ -2344,8 +2364,7 @@ BaseType_t location = 0;
 			/* Nothing. */
 		}
 		#endif	/* ipconfigHAS_DEBUG_PRINTF != 0 */
-
+	} while( ipFALSE_BOOL );
- error_exit:
 
 	if( ( usChecksum == ipUNHANDLED_PROTOCOL ) || 
 		( usChecksum == ipINVALID_LENGTH ) )
@@ -2482,7 +2501,9 @@ size_t uxDataLengthBytes = uxByteCount;
 	xLastSource.u8ptr = ( uint8_t * ) ( xSource.u8ptr + ( uxDataLengthBytes & ~( ( size_t ) 1 ) ) );
 
 	/* Half-word aligned. */
-	/* The operator "<" is being applied to the pointers "xSource.u16ptr" and "xLastSource.u16ptr", which do not point into the same object. */
+	/* Coverity does not like Unions. Warning issued here: "The operator "<"
+	 * is being applied to the pointers "xSource.u16ptr" and "xLastSource.u16ptr",
+	 * which do not point into the same object." */
 	while( xSource.u16ptr < xLastSource.u16ptr )
 	{
 		/* At least one more short. */
@@ -2516,6 +2537,8 @@ size_t uxDataLengthBytes = uxByteCount;
 }
 /*-----------------------------------------------------------*/
 
+/* This function is used in other files, has external linkage e.g. in
+ * FreeRTOS_DNS.c. Not to be made static. */
 void vReturnEthernetFrame( NetworkBufferDescriptor_t * pxNetworkBuffer, BaseType_t xReleaseAfterSend )
 {
 EthernetHeader_t *pxEthernetHeader;
@@ -2554,6 +2577,7 @@ EthernetHeader_t *pxEthernetHeader;
 	if( pxNetworkBuffer != NULL )
 #endif
 	{
+		/* Map the Buffer to Ethernet Header struct for easy access to fields. */
 		pxEthernetHeader = ipPOINTER_CAST( EthernetHeader_t *, pxNetworkBuffer->pucEthernetBuffer );
 
 		/* Swap source and destination MAC addresses. */
@@ -2769,7 +2793,8 @@ BaseType_t FreeRTOS_IsNetworkUp( void )
 	}
 #endif
 /*-----------------------------------------------------------*/
-
+/* Utility function: Convert error number to a human readable
+ * string. Decalartion in FreeRTOS_errno_TCP.h. */
 const char *FreeRTOS_strerror_r( BaseType_t xErrnum, char *pcBuffer, size_t uxLength )
 {
 const char *pcName;

FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/FreeRTOS_TCP_IP.c

@@ -874,6 +874,9 @@ NetworkBufferDescriptor_t xTempBuffer;
 		usPacketIdentifier++;
 		pxIPHeader->usFragmentOffset = 0U;
 
+		/* Important: tell NIC driver how many bytes must be sent. */
+		pxNetworkBuffer->xDataLength = ulLen + ipSIZE_OF_ETH_HEADER;
+
 		#if( ipconfigDRIVER_INCLUDED_TX_IP_CHECKSUM == 0 )
 		{
 			/* calculate the IP header checksum, in case the driver won't do that. */
@@ -899,9 +902,6 @@ NetworkBufferDescriptor_t xTempBuffer;
 		}
 		#endif
 
-		/* Important: tell NIC driver how many bytes must be sent. */
-		pxNetworkBuffer->xDataLength = ulLen + ipSIZE_OF_ETH_HEADER;
-
 		/* Fill in the destination MAC addresses. */
 		( void ) memcpy( &( pxEthernetHeader->xDestinationAddress ),
 						 &( pxEthernetHeader->xSourceAddress ),
@@ -2000,6 +2000,7 @@ int32_t lCount, lLength;
 
 	/* A txStream has been created already, see if the socket has new data for
 	the sliding window.
+
 	uxStreamBufferMidSpace() returns the distance between rxHead and rxMid.  It
 	contains new Tx data which has not been passed to the sliding window yet.
 	The oldest data not-yet-confirmed can be found at rxTail. */
@@ -2009,6 +2010,7 @@ int32_t lCount, lLength;
 	{
 		/* All data between txMid and rxHead will now be passed to the sliding
 		window manager, so it can start transmitting them.
+
 		Hand over the new data to the sliding window handler.  It will be
 		split-up in chunks of 1460 bytes each (or less, depending on
 		ipconfigTCP_MSS). */
@@ -2141,6 +2143,7 @@ uint16_t usLength;
 
 	/* Determine the length and the offset of the user-data sent to this
 	node.
+
 	The size of the TCP header is given in a multiple of 4-byte words (single
 	byte, needs no ntoh() translation).  A shift-right 2: is the same as
 	(offset >> 4) * 4. */
@@ -2216,6 +2219,7 @@ BaseType_t xResult = 0;
 	{
 		/* See if way may accept the data contents and forward it to the socket
 		owner.
+
 		If it can't be "accept"ed it may have to be stored and send a selective
 		ack (SACK) option to confirm it.  In that case, lTCPAddRxdata() will be
 		called later to store an out-of-order packet (in case lOffset is
@@ -3504,3 +3508,4 @@ const ListItem_t *pxEndTCP = ipPOINTER_CAST( const ListItem_t *, listGET_END_MAR
 #ifdef FREERTOS_TCP_ENABLE_VERIFICATION
 	#include "aws_freertos_tcp_verification_access_tcp_define.h"
 #endif
+

FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/FreeRTOS_TCP_WIN.c

@@ -1910,8 +1910,8 @@ const int32_t l500ms = 500;
 
 #if( ipconfigUSE_TCP_WIN == 0 )
 
-	static BaseType_t prvTCPWindowTxHasSpace( TCPWindow_t *pxWindow, uint32_t ulWindowSize );
+	static BaseType_t prvTCPWindowTxHasSpace( TCPWindow_t const * pxWindow, uint32_t ulWindowSize );
-	static BaseType_t prvTCPWindowTxHasSpace( TCPWindow_t *pxWindow, uint32_t ulWindowSize )
+	static BaseType_t prvTCPWindowTxHasSpace( TCPWindow_t const * pxWindow, uint32_t ulWindowSize )
 	{
 	BaseType_t xReturn;
 
@@ -1934,7 +1934,7 @@ const int32_t l500ms = 500;
 
 	BaseType_t xTCPWindowTxHasData( TCPWindow_t const *pxWindow, uint32_t ulWindowSize, TickType_t *pulDelay )
 	{
-	TCPSegment_t *pxSegment = &( pxWindow->xTxSegment );
+	TCPSegment_t const *pxSegment = &( pxWindow->xTxSegment );
 	BaseType_t xReturn;
 	TickType_t ulAge, ulMaxAge;
 

FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/include/FreeRTOSIPConfigDefaults.h

@@ -317,20 +317,25 @@ from the FreeRTOSIPConfig.h configuration header file. */
 	#define ipconfigALLOW_SOCKET_SEND_WITHOUT_BIND	1
 #endif
 
-
+/* Configuration to control whether packets with IP options,
-#ifndef ipconfigIP_PASS_PACKETS_WITH_IP_OPTIONS
+ * received over the network, should be passed up to the 
-	#define ipconfigIP_PASS_PACKETS_WITH_IP_OPTIONS	1
+ * software stack OR should be dropped.
-#endif
+ * If set to 1, the stack accepts IP packets that contain IP options, but does
-
+ * not process the options (IP options are not supported).
-#ifndef ipconfigUDP_PASS_ZERO_CHECKSUM_PACKETS
+ * If set to 0, the stack will drop IP packets that contain IP options.
-	#define ipconfigUDP_PASS_ZERO_CHECKSUM_PACKETS	0
+ */
-#endif
-
-
 #ifndef ipconfigIP_PASS_PACKETS_WITH_IP_OPTIONS
 	#define ipconfigIP_PASS_PACKETS_WITH_IP_OPTIONS	1
 #endif
 
+/* Configuration to control whether UDP packets with 
+ * checksum value of zero should be passed up the software
+ * stack OR should be dropped.
+ * If set to 1, the stack will accept UDP packets that have their checksum 
+ * value set to 0.
+ * If set to 0, the stack will drop UDP packets that have their checksum value
+ * set to 0.
+ */
 #ifndef ipconfigUDP_PASS_ZERO_CHECKSUM_PACKETS
 	#define ipconfigUDP_PASS_ZERO_CHECKSUM_PACKETS	0
 #endif

FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/include/FreeRTOS_IP.h

@@ -304,6 +304,12 @@ BaseType_t FreeRTOS_IsNetworkUp( void );
 	UBaseType_t uxGetMinimumIPQueueSpace( void );
 #endif
 
+#if ( ipconfigHAS_PRINTF != 0 )
+	extern void vPrintResourceStats( void );
+#else
+	#define vPrintResourceStats()	do {} while( ipFALSE_BOOL )
+#endif
+
 /*
  * Defined in FreeRTOS_Sockets.c
  * //_RB_ Don't think this comment is correct.  If this is for internal use only it should appear after all the public API functions and not start with FreeRTOS_.

FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/include/tcp_dump_packets.h

@@ -1,3 +1,28 @@
+/*
+ * FreeRTOS+TCP V2.2.1
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * http://aws.amazon.com/freertos
+ * http://www.FreeRTOS.org
+ */
+
 /*
  * dump_packets.c
  * Used in the PC/Win project to dump Ethernet packets, along with some description.

FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/include/tcp_mem_stats.h

@@ -1,3 +1,28 @@
+/*
+ * FreeRTOS+TCP V2.2.1
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * http://aws.amazon.com/freertos
+ * http://www.FreeRTOS.org
+ */
+
 /*
  * tcp_mem_stats.h
  */