Let valid broadcast packets in when endpoint is not yet up (#1240)

* Let valid broadcast packets in when endpoint is not yet up

* Update comments

* Fix formatting

Author: tony-josi-aws

source/FreeRTOS_IPv4.c

@@ -435,20 +435,37 @@ enum eFrameProcessingResult prvAllowIPPacketIPv4( const struct xIP_PACKET * cons
         {
             /* Endpoint is down */
 
+            /* Check if the destination MAC address is a broadcast MAC address. */
+            if( memcmp( xBroadcastMACAddress.ucBytes,
+                        pxIPPacket->xEthernetHeader.xDestinationAddress.ucBytes,
+                        sizeof( MACAddress_t ) ) == 0 )
+            {
+                if( ulDestinationIPAddress != FREERTOS_INADDR_BROADCAST )
+                {
+                    /* Ethernet address is a broadcast address, but the IP address is not a
+                     * broadcast address. */
+                    eReturn = eReleaseBuffer;
+                }
+                else
+                {
+                    /* Accept valid broadcast packet. */
+                }
+            }
+
             /* RFC 2131: https://datatracker.ietf.org/doc/html/rfc2131#autoid-8
              * The TCP/IP software SHOULD accept and
              * forward to the IP layer any IP packets delivered to the client's
              * hardware address before the IP address is configured; DHCP servers
              * and BOOTP relay agents may not be able to deliver DHCP messages to
              * clients that cannot accept hardware unicast datagrams before the
              * TCP/IP software is configured. */
-            if( ( memcmp( pxEndPoint->xMACAddress.ucBytes,
-                          pxIPPacket->xEthernetHeader.xDestinationAddress.ucBytes,
-                          sizeof( MACAddress_t ) ) != 0 ) )
+            else if( ( memcmp( pxEndPoint->xMACAddress.ucBytes,
+                               pxIPPacket->xEthernetHeader.xDestinationAddress.ucBytes,
+                               sizeof( MACAddress_t ) ) != 0 ) )
             {
                 /* The endpoint is not up, and the destination MAC address of the
-                 * packet is not matching the endpoint's MAC address. Drop the
-                 * packet. */
+                 * packet is not matching the endpoint's MAC address nor broadcast
+                 * MAC address. Drop the packet. */
                 eReturn = eReleaseBuffer;
             }
             else

test/unit-test/FreeRTOS_IPv4/FreeRTOS_IPv4_utest.c

@@ -672,6 +672,88 @@ void test_prvAllowIPPacketIPv4_EndpointDown_UnHappyPath( void )
     TEST_ASSERT_EQUAL( eReleaseBuffer, eResult );
 }
 
+/**
+ * @brief test_prvAllowIPPacketIPv4_EndpointDown_HappyPath
+ * To validate if prvAllowIPPacketIPv4() returns eProcessBuffer when
+ * endpoint is down and the packet is broadcast packet with destination
+ * MAC address as broadcast MAC and the destination IP as broadcast IP
+ */
+void test_prvAllowIPPacketIPv4_EndpointDown_UnHappyPathBroadcast( void )
+{
+    eFrameProcessingResult_t eResult;
+    IPPacket_t * pxIPPacket;
+    NetworkBufferDescriptor_t * pxNetworkBuffer, xNetworkBuffer;
+    UBaseType_t uxHeaderLength = 0;
+    uint8_t ucEthBuffer[ ipconfigTCP_MSS ];
+    IPHeader_t * pxIPHeader;
+    NetworkEndPoint_t xEndpoint;
+
+    memset( ucEthBuffer, 0, ipconfigTCP_MSS );
+
+    pxNetworkBuffer = &xNetworkBuffer;
+    pxNetworkBuffer->pucEthernetBuffer = ucEthBuffer;
+    pxNetworkBuffer->pxEndPoint = &xEndpoint;
+    pxIPPacket = ( IPPacket_t * ) pxNetworkBuffer->pucEthernetBuffer;
+    pxIPHeader = &( pxIPPacket->xIPHeader );
+
+    pxIPHeader->ucVersionHeaderLength = 0x45;
+
+    pxIPHeader->ulDestinationIPAddress = 0xFFFFFFFF;
+
+    memset( pxIPPacket->xEthernetHeader.xDestinationAddress.ucBytes, 0xFF, sizeof( MACAddress_t ) );
+    memset( xEndpoint.xMACAddress.ucBytes, 0xCD, sizeof( MACAddress_t ) );
+
+    FreeRTOS_IsEndPointUp_ExpectAndReturn( &xEndpoint, pdFALSE );
+    FreeRTOS_FindEndPointOnMAC_ExpectAnyArgsAndReturn( NULL );
+
+    usGenerateChecksum_ExpectAndReturn( 0U, ( uint8_t * ) &( pxIPHeader->ucVersionHeaderLength ), ( size_t ) uxHeaderLength, ipCORRECT_CRC );
+
+    usGenerateProtocolChecksum_ExpectAndReturn( ( uint8_t * ) ( pxNetworkBuffer->pucEthernetBuffer ), pxNetworkBuffer->xDataLength, pdFALSE, ipCORRECT_CRC );
+
+    eResult = prvAllowIPPacketIPv4( pxIPPacket, pxNetworkBuffer, uxHeaderLength );
+
+    TEST_ASSERT_EQUAL( eProcessBuffer, eResult );
+}
+
+/**
+ * @brief test_prvAllowIPPacketIPv4_EndpointDown_HappyPath
+ * To validate if prvAllowIPPacketIPv4() returns eReleaseBuffer when
+ * endpoint is down and the packet is malformed broadcast packet with  destination
+ * MAC address as broadcast MAC and but the destination IP not broadcast IP
+ */
+void test_prvAllowIPPacketIPv4_EndpointDown_UnHappyPathIncorrectBroadcast( void )
+{
+    eFrameProcessingResult_t eResult;
+    IPPacket_t * pxIPPacket;
+    NetworkBufferDescriptor_t * pxNetworkBuffer, xNetworkBuffer;
+    UBaseType_t uxHeaderLength = 0;
+    uint8_t ucEthBuffer[ ipconfigTCP_MSS ];
+    IPHeader_t * pxIPHeader;
+    NetworkEndPoint_t xEndpoint;
+
+    memset( ucEthBuffer, 0, ipconfigTCP_MSS );
+
+    pxNetworkBuffer = &xNetworkBuffer;
+    pxNetworkBuffer->pucEthernetBuffer = ucEthBuffer;
+    pxNetworkBuffer->pxEndPoint = &xEndpoint;
+    pxIPPacket = ( IPPacket_t * ) pxNetworkBuffer->pucEthernetBuffer;
+    pxIPHeader = &( pxIPPacket->xIPHeader );
+
+    pxIPHeader->ucVersionHeaderLength = 0x45;
+
+    pxIPHeader->ulDestinationIPAddress = 0xFFFFABCD;
+
+    memset( pxIPPacket->xEthernetHeader.xDestinationAddress.ucBytes, 0xFF, sizeof( MACAddress_t ) );
+    memset( xEndpoint.xMACAddress.ucBytes, 0xCD, sizeof( MACAddress_t ) );
+
+    FreeRTOS_IsEndPointUp_ExpectAndReturn( &xEndpoint, pdFALSE );
+
+    eResult = prvAllowIPPacketIPv4( pxIPPacket, pxNetworkBuffer, uxHeaderLength );
+
+    TEST_ASSERT_EQUAL( eReleaseBuffer, eResult );
+}
+
+
 /**
  * @brief test_prvAllowIPPacketIPv4_DestMACBrdCast_DestIPBroadcastAndIncorrectChkSum
  * To validate if prvAllowIPPacketIPv4() when

test/unit-test/FreeRTOS_Sockets/FreeRTOS_Sockets_privates_utest.c

@@ -110,6 +110,8 @@ void test_prvFindSelectedSocket_SendFail( void )
 {
     SocketSelect_t xSocketSet;
 
+    xSocketSet.xSelectGroup = NULL;
+
     xEventGroupClearBits_ExpectAndReturn( xSocketSet.xSelectGroup, ( BaseType_t ) eSELECT_CALL_IP, pdFALSE );
 
     xSendEventStructToIPTask_ExpectAnyArgsAndReturn( pdFAIL );
@@ -124,6 +126,8 @@ void test_prvFindSelectedSocket_SendSuccess( void )
 {
     SocketSelect_t xSocketSet;
 
+    xSocketSet.xSelectGroup = NULL;
+
     xEventGroupClearBits_ExpectAndReturn( xSocketSet.xSelectGroup, ( BaseType_t ) eSELECT_CALL_IP, pdFALSE );
 
     xSendEventStructToIPTask_ExpectAnyArgsAndReturn( pdPASS );