Adds support for receiving Multicast Group addresses + IGMP ( IPv4 only )

Adds 2 function pointers to the network interface struct that handle adding and removing  multicast MAC addresses.
Updates IGMP to use function pointers through the network interface.
Makes the Add/Remove Multicast functions private to NetworkInterface.c They are now used through pointers in the NetworkInterface_t struct.
Improves the SAME70 driver to handle adding/removing muticast MAC addresses

Author: Emil Popov

source/FreeRTOS_DNS_Networking.c

@@ -84,6 +84,11 @@
              * going to be '0' i.e. success. Thus, return value is discarded */
             ( void ) FreeRTOS_setsockopt( xSocket, 0, FREERTOS_SO_SNDTIMEO, &( uxWriteTimeOut_ticks ), sizeof( TickType_t ) );
             ( void ) FreeRTOS_setsockopt( xSocket, 0, FREERTOS_SO_RCVTIMEO, &( uxReadTimeOut_ticks ), sizeof( TickType_t ) );
+            #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+                /* Since this socket may be used for LLMNR or mDNS, set the multicast TTL to 1. */
+                uint8_t ucMulticastTTL = 1;
+                ( void ) FreeRTOS_setsockopt( xSocket, 0, FREERTOS_SO_IP_MULTICAST_TTL, &( ucMulticastTTL ), sizeof( uint8_t ) );
+            #endif
         }
 
         return xSocket;

source/FreeRTOS_IGMP.c

@@ -59,6 +59,9 @@
 #include "FreeRTOS_DNS.h"
 #include "FreeRTOS_Routing.h"
 #include "FreeRTOS_ND.h"
+#if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+    #include "FreeRTOS_IGMP.h"
+#endif
 
 /** @brief Time delay between repeated attempts to initialise the network hardware. */
 #ifndef ipINITIALISATION_RETRY_DELAY
@@ -467,6 +470,26 @@ static void prvProcessIPEventsAndTimers( void )
             /* xQueueReceive() returned because of a normal time-out. */
             break;
 
+            #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+                case eSocketOptAddMembership:
+                   {
+                       MCastGroupDesc_t * pxMCG = ( MCastGroupDesc_t * ) xReceivedEvent.pvData;
+                       ( void ) vModifyMulticastMembership( pxMCG, eSocketOptAddMembership );
+                       break;
+                   }
+
+                case eSocketOptDropMembership:
+                   {
+                       MCastGroupDesc_t * pxMCG = ( MCastGroupDesc_t * ) xReceivedEvent.pvData;
+                       ( void ) vModifyMulticastMembership( pxMCG, eSocketOptDropMembership );
+                       break;
+                   }
+
+                case eIGMPEvent:
+                    ( void ) vHandleIGMP_Event();
+                    break;
+            #endif /* ( ipconfigSUPPORT_IP_MULTICAST != 0) */
+
         default:
             /* Should not get here. */
             break;
@@ -526,6 +549,11 @@ static void prvIPTask_Initialise( void )
     }
     #endif /* ( ( ipconfigUSE_DNS_CACHE != 0 ) && ( ipconfigUSE_DNS != 0 ) ) */
 
+    /* Init the list that will hold scheduled IGMP reports. */
+    #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+        ( void ) vIGMP_Init();
+    #endif
+
     /* Initialisation is complete and events can now be processed. */
     xIPTaskInitialised = pdTRUE;
 }
@@ -1980,6 +2008,13 @@ static eFrameProcessingResult_t prvProcessIPPacket( const IPPacket_t * pxIPPacke
                             break;
                     #endif /* ( ipconfigUSE_IPv6 != 0 ) */
 
+                    #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+                        case ipPROTOCOL_IGMP:
+                            /* The IP packet contained an IGMP frame.  */
+                            eReturn = eProcessIGMPPacket( pxNetworkBuffer );
+                            break;
+                    #endif /* ( ipconfigSUPPORT_IP_MULTICAST != 0 ) */
+
                     case ipPROTOCOL_UDP:
                         /* The IP packet contained a UDP frame. */
 

source/FreeRTOS_IP.c

@@ -55,6 +55,9 @@
 #include "NetworkBufferManagement.h"
 #include "FreeRTOS_Routing.h"
 #include "FreeRTOS_DNS.h"
+#if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+    #include "FreeRTOS_IGMP.h"
+#endif
 /*-----------------------------------------------------------*/
 
 /** @brief 'xAllNetworksUp' becomes pdTRUE as soon as all network interfaces have
@@ -110,6 +113,11 @@ static IPTimer_t xARPTimer;
     static IPTimer_t xDNSTimer;
 #endif
 
+#if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+    /** @brief IGMP timer. Used for sending scheduled IGMP Reports */
+    static IPTimer_t xIGMPTimer;
+#endif
+
 /** @brief As long as not all networks are up, repeat initialisation by calling the
  * xNetworkInterfaceInitialise() function of the interfaces that are not ready. */
 
@@ -176,6 +184,15 @@ TickType_t xCalculateSleepTime( void )
     }
     #endif
 
+    #if ( ipconfigSUPPORT_IP_MULTICAST == 1 )
+    {
+        if( xIGMPTimer.ulRemainingTime < uxMaximumSleepTime )
+        {
+            uxMaximumSleepTime = xIGMPTimer.ulRemainingTime;
+        }
+    }
+    #endif /* ipconfigSUPPORT_IP_MULTICAST */
+
     #if ( ipconfigDNS_USE_CALLBACKS != 0 )
     {
         if( xDNSTimer.bActive != pdFALSE_UNSIGNED )
@@ -312,6 +329,16 @@ void vCheckNetworkTimers( void )
     vSocketListenNextTime( NULL );
     #endif /* ipconfigUSE_TCP == 1 */
 
+    #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+    {
+        /* Is it time to send any IGMP reports? */
+        if( prvIPTimerCheck( &xIGMPTimer ) != pdFALSE )
+        {
+            ( void ) xSendIGMPEvent();
+        }
+    }
+    #endif /* ipconfigSUPPORT_IP_MULTICAST != 0 */
+
     /* Is it time to trigger the repeated NetworkDown events? */
     if( xAllNetworksUp == pdFALSE )
     {
@@ -412,6 +439,20 @@ void vARPTimerReload( TickType_t xTime )
 
 /*-----------------------------------------------------------*/
 
+#if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+
+/**
+ * @brief Reload the IGMP timer.
+ *
+ * @param[in] xIgmpTickTime: The reload value.
+ */
+    void vIGMPTimerReload( TickType_t xIgmpTickTime )
+    {
+        prvIPTimerReload( &xIGMPTimer, pdMS_TO_TICKS( ipIGMP_TIMER_PERIOD_MS ) );
+    }
+#endif /* ipconfigSUPPORT_IP_MULTICAST */
+/*-----------------------------------------------------------*/
+
 #if ( ipconfigDNS_USE_CALLBACKS != 0 )
 
 /**

source/FreeRTOS_IP_Timers.c

@@ -52,7 +52,9 @@
 #include "FreeRTOS_DNS.h"
 #include "NetworkBufferManagement.h"
 #include "FreeRTOS_Routing.h"
-
+#if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+    #include "FreeRTOS_IGMP.h"
+#endif
 #if ( ipconfigUSE_TCP_MEM_STATS != 0 )
     #include "tcp_mem_stats.h"
 #endif
@@ -738,6 +740,11 @@ Socket_t FreeRTOS_socket( BaseType_t xDomain,
                     pxSocket->u.xUDP.uxMaxPackets = ( UBaseType_t ) ipconfigUDP_MAX_RX_PACKETS;
                 }
                 #endif /* ipconfigUDP_MAX_RX_PACKETS > 0 */
+
+                #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+                    pxSocket->u.xUDP.ucMulticastTTL = ipconfigMULTICAST_DEFAULT_TTL;
+                    vListInitialise( &pxSocket->u.xUDP.xMulticastGroupsList );
+                #endif
             }
 
             #if ( ipconfigUSE_TCP == 1 )
@@ -1432,6 +1439,17 @@ static int32_t prvSendUDPPacket( const FreeRTOS_Socket_t * pxSocket,
     pxNetworkBuffer->usPort = pxDestinationAddress->sin_port;
     pxNetworkBuffer->usBoundPort = ( uint16_t ) socketGET_SOCKET_PORT( pxSocket );
 
+    #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+        if( xIsIPv4Multicast( pxDestinationAddress->sin_address.ulIP_IPv4 ) )
+        {
+            pxNetworkBuffer->ucSendTTL = pxSocket->u.xUDP.ucMulticastTTL;
+        }
+        else
+        {
+            pxNetworkBuffer->ucSendTTL = ipconfigUDP_TIME_TO_LIVE;
+        }
+    #endif
+
     /* The socket options are passed to the IP layer in the
      * space that will eventually get used by the Ethernet header. */
     pxNetworkBuffer->pucEthernetBuffer[ ipSOCKET_OPTIONS_OFFSET ] = pxSocket->ucSocketOptions;
@@ -2132,6 +2150,18 @@ void * vSocketClose( FreeRTOS_Socket_t * pxSocket )
         #endif /* ipconfigETHERNET_DRIVER_FILTERS_PACKETS */
     }
 
+    #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+        if( pxSocket->ucProtocol == ipPROTOCOL_UDP )
+        {
+            /* Un-register all multicast groups that might have been added. */
+            while( listCURRENT_LIST_LENGTH( &( pxSocket->u.xUDP.xMulticastGroupsList ) ) > 0U )
+            {
+                MCastGroupDesc_t * pMCD = ( MCastGroupDesc_t * ) listGET_OWNER_OF_HEAD_ENTRY( &( pxSocket->u.xUDP.xMulticastGroupsList ) );
+                ( void ) vModifyMulticastMembership( pMCD, eSocketOptDropMembership );
+            }
+        }
+    #endif /* ( ipconfigSUPPORT_IP_MULTICAST != 0 ) */
+
     /* Now the socket is not bound the list of waiting packets can be
      * drained. */
     if( pxSocket->ucProtocol == ( uint8_t ) FREERTOS_IPPROTO_UDP )
@@ -2929,6 +2959,20 @@ BaseType_t FreeRTOS_setsockopt( Socket_t xSocket,
                         break;
                 #endif /* ipconfigUSE_TCP == 1 */
 
+                #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+                    case FREERTOS_SO_IP_MULTICAST_TTL:
+                    case FREERTOS_SO_IP_ADD_MEMBERSHIP:
+                    case FREERTOS_SO_IP_DROP_MEMBERSHIP:
+                        /* Use extern here, because we don't want to expose xSetMulticastSocketOption through .h files */
+                        extern BaseType_t xSetMulticastSocketOption( Socket_t xSocket,
+                                                                     int32_t lLevel,
+                                                                     int32_t lOptionName,
+                                                                     const void * pvOptionValue,
+                                                                     size_t uxOptionLength );
+                        xReturn = xSetMulticastSocketOption( xSocket, lLevel, lOptionName, pvOptionValue, uxOptionLength );
+                        break;
+                #endif /* (ipconfigSUPPORT_IP_MULTICAST != 0) */
+
             default:
                 /* No other options are handled. */
                 xReturn = -pdFREERTOS_ERRNO_ENOPROTOOPT;

source/FreeRTOS_Sockets.c

@@ -63,6 +63,9 @@
 /* *INDENT-OFF* */
     #if( ipconfigUSE_IPv4 != 0 )
 /* *INDENT-ON* */
+#if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+    #include "FreeRTOS_IGMP.h"
+#endif
 
 /** @brief The expected IP version and header length coded into the IP header itself. */
 #define ipIP_VERSION_AND_HEADER_LENGTH_BYTE    ( ( uint8_t ) 0x45 )
@@ -229,6 +232,13 @@ void vProcessGeneratedUDPPacket_IPv4( NetworkBufferDescriptor_t * const pxNetwor
             }
             #endif
 
+            #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+                if( ( pxNetworkBuffer->xIPAddress.ulIP_IPv4 != ipLLMNR_IP_ADDR ) && ( pxNetworkBuffer->xIPAddress.ulIP_IPv4 == ipMDNS_IP_ADDRESS ) )
+                {
+                    pxIPHeader->ucTimeToLive = pxNetworkBuffer->ucSendTTL;
+                }
+            #endif
+
             #if ( ipconfigDRIVER_INCLUDED_TX_IP_CHECKSUM == 0 )
             {
                 pxIPHeader->usHeaderChecksum = 0U;
@@ -364,6 +374,40 @@ BaseType_t xProcessReceivedUDPPacket_IPv4( NetworkBufferDescriptor_t * pxNetwork
 
     *pxIsWaitingForARPResolution = pdFALSE;
 
+    #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+
+        /* If this incoming packet is a multicast, we may have a socket for the port, but we still need
+         * to ensure the socket is subscribed to that particular multicast group. Note: Since this stack
+         * does not support port reusing, we don't have to worry about two UDP sockets bound to the exact same
+         * local port, but subscribed to different multicast groups. If this was allowed, this check
+         * would have to be moved to the pxUDPSocketLookup() function itself. */
+        if( ( pxSocket != NULL ) && ( xIsIPv4Multicast( pxUDPPacket->xIPHeader.ulDestinationIPAddress ) ) )
+        {
+            /* Note: There is no need for vTaskSuspendAll/xTaskResumeAll here because only the IP Task
+             * touches the socket's multicast groups list directly. */
+            const ListItem_t * pxIterator;
+            const ListItem_t * xEnd = listGET_END_MARKER( &( pxSocket->u.xUDP.xMulticastGroupsList ) );
+
+            for( pxIterator = ( const ListItem_t * ) listGET_NEXT( xEnd );
+                 pxIterator != ( const ListItem_t * ) xEnd;
+                 pxIterator = ( const ListItem_t * ) listGET_NEXT( pxIterator ) )
+            {
+                MCastGroupDesc_t * pxMCG = ( MCastGroupDesc_t * ) listGET_LIST_ITEM_OWNER( pxIterator );
+
+                if( pxMCG->mreq.imr_multiaddr.sin_address.ulIP_IPv4 == pxUDPPacket->xIPHeader.ulDestinationIPAddress )
+                {
+                    break;
+                }
+            }
+
+            if( pxIterator == ( const ListItem_t * ) xEnd )
+            {
+                /* This socket is not subscribed to this multicast group. Nullify the result from pxUDPSocketLookup() */
+                pxSocket = NULL;
+            }
+        }
+    #endif /* ( ipconfigSUPPORT_IP_MULTICAST != 0 ) */
+
     do
     {
         if( pxSocket != NULL )

source/FreeRTOS_UDP_IPv4.c

@@ -1160,4 +1160,28 @@
     #define ipconfigPORT_SUPPRESS_WARNING    ( 0 )
 #endif
 
+/* Setting to 1 will enable the reception of IPv4 multicast groups
+ * and the associated socket options that need to be set before
+ * a socket would properly receive multicast packets. */
+#ifndef ipconfigSUPPORT_IP_MULTICAST
+    #define ipconfigSUPPORT_IP_MULTICAST    ( 0 )
+#endif
+
+/* Specifies the TTL value that will be used for multicast
+ * UDP packets by default. Can be overridden per socket by
+ * setting the FREERTOS_SO_IP_MULTICAST_TTL socket option. */
+#ifndef ipconfigMULTICAST_DEFAULT_TTL
+    #define ipconfigMULTICAST_DEFAULT_TTL    ( 1 )
+#endif
+
+/* Set to 1 if you plan on implementing IGMP snooping.
+ * When set to 1, the user must implement the following hooks:
+ * eFrameProcessingResult_t eApplicationIgmpFrameReceivedHook( NetworkBufferDescriptor_t * pxNetworkBuffer )
+ * void vApplicationIgmpSendLocalMessageHook( NetworkBufferDescriptor_t * pxNetworkBuffer, uint8_t ucIgmpMsgType, uint32_t uiMulticastGroup )
+ * void vApplicationIgmpEventHook( void )
+ */
+#ifndef ipconfigIGMP_SNOOPING
+    #define ipconfigIGMP_SNOOPING    ( 0 )
+#endif
+
 #endif /* FREERTOS_DEFAULT_IP_CONFIG_H */