Moves more functions to FreeRTOS_Sockets.c

Sends IGMPv2 Leave Group messages whenever the last socket subscribed to a group drops that membership.
Adds ipconfigPERIODIC_MULTICAST_REPORT_INTERVAL for debug purposes when there is no IGMP/MLD querier

Author: Emil Popov

source/FreeRTOS_IGMP.c

@@ -475,12 +475,12 @@ static void prvProcessIPEventsAndTimers( void )
                 case eSocketOptDropMembership:
                    {
                        MulticastAction_t * pxMCA = ( MulticastAction_t * ) xReceivedEvent.pvData;
-                       ( void ) vModifyMulticastMembership( pxMCA, xReceivedEvent.eEventType );
+                       vModifyMulticastMembership( pxMCA, xReceivedEvent.eEventType );
                        break;
                    }
 
-                case eIGMPEvent:
-                    ( void ) vHandleIGMP_Event();
+                case eMulticastTimerEvent:
+                    vHandleIGMP_Event();
                     break;
             #endif /* ( ipconfigSUPPORT_IP_MULTICAST != 0) */
 
@@ -688,7 +688,7 @@ void vIPNetworkUpCalls( struct xNetworkEndPoint * pxEndPoint )
                     pxMRD->xMCastGroupAddress.xIPAddress.xIP_IPv6.ucBytes[ 12 ] = 0xFFU;
                     ( void ) memcpy( &pxMRD->xMCastGroupAddress.xIPAddress.xIP_IPv6.ucBytes[ 13 ], &pxEndPoint->ipv6_settings.xIPAddress.ucBytes[ 13 ], 3 );
 
-                    if( pdTRUE != xAddIGMPReportToList( pxMRD ) )
+                    if( pdTRUE != xAddMulticastReportToList( pxMRD ) )
                     {
                         vPortFree( pxMRD );
                         pxMRD = NULL;

source/FreeRTOS_IP.c

@@ -334,7 +334,7 @@ void vCheckNetworkTimers( void )
         /* Is it time to send any IGMP reports? */
         if( prvIPTimerCheck( &xIGMPTimer ) != pdFALSE )
         {
-            ( void ) xSendIGMPEvent();
+            ( void ) xSendMulticastTimerEvent();
         }
     }
     #endif /* ipconfigSUPPORT_IP_MULTICAST != 0 */
@@ -448,7 +448,7 @@ void vARPTimerReload( TickType_t xTime )
  */
     void vIGMPTimerReload( TickType_t xIgmpTickTime )
     {
-        prvIPTimerReload( &xIGMPTimer, pdMS_TO_TICKS( ipIGMP_TIMER_PERIOD_MS ) );
+        prvIPTimerReload( &xIGMPTimer, pdMS_TO_TICKS( igmpMULTICAST_EVENT_PERIOD_MS ) );
     }
 #endif /* ipconfigSUPPORT_IP_MULTICAST */
 /*-----------------------------------------------------------*/

source/FreeRTOS_IP_Timers.c

@@ -377,6 +377,7 @@ static int32_t prvSendTo_ActualSend( const FreeRTOS_Socket_t * pxSocket,
                                              int32_t lOptionName,
                                              const void * pvOptionValue,
                                              size_t uxOptionLength );
+    static void prvDropMulticastMembership( FreeRTOS_Socket_t * pxSocket );
 #endif /* ( ipconfigSUPPORT_IP_MULTICAST != 0 ) */
 
 /*-----------------------------------------------------------*/
@@ -6612,4 +6613,205 @@ void * pvSocketGetSocketID( const ConstSocket_t xSocket )
 
         return xReturn;
     }
+
+/**
+ * @brief Adds or drops a multicast group to/from a socket.
+ *
+ * @param[in] pxMulticastGroup: The multicast group descriptor. Also holds the socket that this call is for.
+ * @param[in] bAction: MUST be eSocketOptAddMembership or eSocketOptDropMembership.
+ */
+    void vModifyMulticastMembership( MulticastAction_t * pxMulticastAction,
+                                     uint8_t bAction )
+    {
+        uint8_t MCastMacBytes[ 6 ];
+        FreeRTOS_Socket_t * pxSocket = pxMulticastAction->pxSocket;
+        uint8_t bFreeMatchedItem = pdFALSE;
+        NetworkInterface_t * pxNetIf = pxMulticastAction->pxInterface;
+        BaseType_t bReportItemConsumed = pdFALSE;
+
+        configASSERT( pxSocket != NULL );
+
+        /* Note: This function is only called with eSocketOptDropMembership or eSocketOptAddMembership*/
+
+        /* This TCP stack does NOT support sockets subscribing to more than one multicast group.
+         * If the socket is already subscribed to a multicast group, we need to unsubscribe it and remove the
+         * IGMP/MLD reports corresponding to that group address.  */
+        prvDropMulticastMembership( pxSocket );
+
+        if( eSocketOptAddMembership == bAction )
+        {
+            /* Store the multicast address. */
+            ( void ) memcpy( &( pxSocket->u.xUDP.xMulticastAddress ), &( pxMulticastAction->xMulticastGroup ), sizeof( pxSocket->u.xUDP.xMulticastAddress ) );
+
+            if( pxSocket->bits.bIsIPv6 == pdFALSE )
+            {
+                vSetMultiCastIPv4MacAddress( pxMulticastAction->xMulticastGroup.ulIP_IPv4, MCastMacBytes );
+            }
+            else
+            {
+                vSetMultiCastIPv6MacAddress( &( pxMulticastAction->xMulticastGroup.xIP_IPv6 ), MCastMacBytes );
+            }
+
+            /* Inform the network driver */
+            if( pxNetIf )
+            {
+                if( pxNetIf->pfAddMulticastMAC != NULL )
+                {
+                    pxNetIf->pfAddMulticastMAC( MCastMacBytes );
+                }
+            }
+            else
+            {
+                /* pxNetIf is NULL. For IPv4 that means "use all interfaces". For IPv6, that means "use the default multicast interface"
+                 * FreeRTOS+TCP does not have the notion of default multicast interface so for now, subscribe on all. */
+                for( pxNetIf = FreeRTOS_FirstNetworkInterface(); pxNetIf != NULL; pxNetIf = FreeRTOS_NextNetworkInterface( pxNetIf ) )
+                {
+                    if( pxNetIf->pfAddMulticastMAC != NULL )
+                    {
+                        pxNetIf->pfAddMulticastMAC( MCastMacBytes );
+                    }
+                }
+            }
+
+            /* Remember which interface(s) this socket is subscribed on. */
+            pxSocket->u.xUDP.pxMulticastNetIf = pxMulticastAction->pxInterface;
+
+            /* Since we've added a multicast group to this socket, we need to prepare an IGMP/MLD report
+             * for when we receive an IGMP/MLD query. Keep in mind that such a report might already exist.
+             * If such an IGMP/MLD report is already present in the list, we will increment it's socket
+             * count and free the report we have here. In either case, the MulticastAction_t that we were
+             * passed, no longer needs to hold a reference to this multicast report. */
+            do
+            {
+                if( pxMulticastAction->pxMCastReportData == NULL )
+                {
+                    break;
+                }
+
+                if( pxMulticastAction->pxMCastReportData->xMCastGroupAddress.xIs_IPv6 == pdTRUE )
+                {
+                    /* RFC2710 end of section section 5 and RFC3810 section 6:
+                     * ff02::1 is a special case and we do not send reports for it. */
+                    static const struct xIPv6_Address FreeRTOS_in6addr_allnodes = { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } };
+
+                    if( memcmp( pxMulticastAction->pxMCastReportData->xMCastGroupAddress.xIPAddress.xIP_IPv6.ucBytes, FreeRTOS_in6addr_allnodes.ucBytes, sizeof( IPv6_Address_t ) ) == 0 )
+                    {
+                        break;
+                    }
+
+                    /* RFC2710 end of section section 5 and RFC3810 section 6:
+                     * Never send reports for multicast scopes of: 0 (reserved) or 1 (node-local).
+                     * Note: the address was already checked to be a valid multicast in FreeRTOS_setsockopt()*/
+                    if( ( pxMulticastAction->pxMCastReportData->xMCastGroupAddress.xIPAddress.xIP_IPv6.ucBytes[ 1 ] & 0x0FU ) <= 1 )
+                    {
+                        break;
+                    }
+                }
+                else
+                {
+                    /* RFC2236 end of section 6:
+                     * 224.0.0.1 is a special case and we do not send reports for it. */
+                    if( pxMulticastAction->pxMCastReportData->xMCastGroupAddress.xIPAddress.ulIP_IPv4 == igmpIGMP_IP_ADDR )
+                    {
+                        break;
+                    }
+                }
+
+                bReportItemConsumed = xAddMulticastReportToList( pxMulticastAction->pxMCastReportData );
+            } while( pdFALSE );
+
+            /* If the report was a special case address or was not consumed by
+             * xAddMulticastReportToList(), free the multicast report. */
+            if( bReportItemConsumed == pdFALSE )
+            {
+                vPortFree( pxMulticastAction->pxMCastReportData );
+                pxMulticastAction->pxMCastReportData = NULL;
+            }
+        }
+
+        /* Free the message that was sent to us. */
+        vPortFree( pxMulticastAction );
+    }
+
+    static void prvDropMulticastMembership( FreeRTOS_Socket_t * pxSocket )
+    {
+        uint8_t MCastMacBytes[ 6 ];
+        UBaseType_t uxLeaveGroup = pdFALSE_UNSIGNED;
+        NetworkInterface_t * pxNetIf = pxSocket->u.xUDP.pxMulticastNetIf;
+
+        if( pxSocket->bits.bIsIPv6 == pdTRUE_UNSIGNED )
+        {
+            /* IPv6 */
+            if( xIsIPv6AllowedMulticast( &( pxSocket->u.xUDP.xMulticastAddress.xIP_IPv6 ) ) )
+            {
+                uxLeaveGroup = pdTRUE_UNSIGNED;
+
+                if( pxNetIf )
+                {
+                    if( pxNetIf->pfRemoveMulticastMAC != NULL )
+                    {
+                        vSetMultiCastIPv6MacAddress( &( pxSocket->u.xUDP.xMulticastAddress.xIP_IPv6 ), MCastMacBytes );
+                        pxNetIf->pfRemoveMulticastMAC( MCastMacBytes );
+                    }
+                }
+                else
+                {
+                }
+            }
+            else
+            {
+                /* Whatever is stored in pxSocket->u.xUDP.xMulticastAddress is not a valid multicast group
+                 * or prvDropMulticastMembership was called for a socket that is not still subscribed to a multicast group.
+                 * Do nothing. */
+            }
+        }
+        else
+        {
+            /* IPv4 */
+            if( xIsIPv4Multicast( pxSocket->u.xUDP.xMulticastAddress.ulIP_IPv4 ) )
+            {
+                uxLeaveGroup = pdTRUE_UNSIGNED;
+
+                vSetMultiCastIPv4MacAddress( pxSocket->u.xUDP.xMulticastAddress.ulIP_IPv4, MCastMacBytes );
+
+                if( pxNetIf )
+                {
+                    if( pxNetIf->pfRemoveMulticastMAC != NULL )
+                    {
+                        pxNetIf->pfRemoveMulticastMAC( MCastMacBytes );
+                    }
+                }
+                else
+                {
+                    /* pxNetIf is NULL. For IPv4 that means "all interfaces", so unsubscribe from all. */
+                    for( pxNetIf = FreeRTOS_FirstNetworkInterface(); pxNetIf != NULL; pxNetIf = FreeRTOS_NextNetworkInterface( pxNetIf ) )
+                    {
+                        if( pxNetIf->pfRemoveMulticastMAC != NULL )
+                        {
+                            pxNetIf->pfRemoveMulticastMAC( MCastMacBytes );
+                        }
+                    }
+                }
+            }
+            else
+            {
+                /* Whatever is stored in pxSocket->u.xUDP.xMulticastAddress is not a valid multicast group
+                 * or prvDropMulticastMembership was called for a socket that is not still subscribed to a multicast group.
+                 * Do nothing. */
+            }
+        }
+
+        if( uxLeaveGroup == pdTRUE_UNSIGNED )
+        {
+            /* Locate the IGMP/MLD report for this group. Decrement its socket count and
+             * if it becomes zero, remove it from the list and free it. */
+            vRemoveMulticastReportFromList( &( pxSocket->u.xUDP.xMulticastAddress ), ( UBaseType_t ) pxSocket->bits.bIsIPv6 );
+        }
+
+        /* Invalidate the multicast group address to prevent erroneous matches if someone calls
+         * FREERTOS_SO_IP_DROP_MEMBERSHIP multiple times. */
+        memset( &pxSocket->u.xUDP.xMulticastAddress, 0x00, sizeof( pxSocket->u.xUDP.xMulticastAddress ) );
+        pxSocket->u.xUDP.pxMulticastNetIf = NULL; /* not really needed, but just looks cleaner when debugging. */
+    }
+
 #endif /* ( ipconfigSUPPORT_IP_MULTICAST != 0 ) */

source/FreeRTOS_Sockets.c

@@ -3321,6 +3321,24 @@
 
 /*---------------------------------------------------------------------------*/
 
+/*
+ * ipconfigPERIODIC_MULTICAST_REPORT_INTERVAL
+ *
+ * Type: BaseType_t
+ * Unit: count of igmpMULTICAST_EVENT_PERIOD_MS
+ *
+ * When set to -1, no periodic unsolicited multicast reports are sent out.
+ * This is the correct behavior. For debug purposes, set to > 0 to cause
+ * periodic sending of multicast reports even if there are no IGMP/MLD
+ * queries heard. Example: 150 = 15.0 seconds.
+ * Note: Maybe remove that ?
+ */
+#ifndef ipconfigPERIODIC_MULTICAST_REPORT_INTERVAL
+    #define ipconfigPERIODIC_MULTICAST_REPORT_INTERVAL    ( -1 )
+#endif
+
+/*---------------------------------------------------------------------------*/
+
 /*
  * ipconfigMULTICAST_DEFAULT_TTL
  *

source/include/FreeRTOSIPConfigDefaults.h

@@ -46,26 +46,26 @@
     #include "event_groups.h"
 
 
-/** @brief IGMP times events at 100ms. */
-    #define ipIGMP_TIMER_PERIOD_MS         ( 100U )
+/** @brief IGMP times events at 100ms. Use this interval for MLD as well. */
+    #define igmpMULTICAST_EVENT_PERIOD_MS    ( 100U )
 
 /* IGMP protocol definitions. */
-    #define ipIGMP_MEMBERSHIP_QUERY        ( ( uint8_t ) 0x11U )      /**< IGMP membership query. */
-    #define ipIGMP_MEMBERSHIP_REPORT_V1    ( ( uint8_t ) 0x12U )      /**< IGMP v1 and v2 membership report. */
-    #define ipIGMP_MEMBERSHIP_REPORT_V2    ( ( uint8_t ) 0x16U )      /**< IGMP v1 and v2 membership report. */
-    #define ipIGMP_MEMBERSHIP_REPORT_V3    ( ( uint8_t ) 0x22U )      /**< IGMP v3 membership report. */
-    #define ipIGMP_LEAVE_GROUP             ( ( uint8_t ) 0x17U )      /**< IGMP leave group */
+    #define igmpIGMP_MEMBERSHIP_QUERY        ( ( uint8_t ) 0x11U )      /**< IGMP membership query. */
+    #define igmpIGMP_MEMBERSHIP_REPORT_V1    ( ( uint8_t ) 0x12U )      /**< IGMP v1 and v2 membership report. */
+    #define igmpIGMP_MEMBERSHIP_REPORT_V2    ( ( uint8_t ) 0x16U )      /**< IGMP v1 and v2 membership report. */
+    #define igmpIGMP_MEMBERSHIP_REPORT_V3    ( ( uint8_t ) 0x22U )      /**< IGMP v3 membership report. */
+    #define igmpIGMP_LEAVE_GROUP             ( ( uint8_t ) 0x17U )      /**< IGMP leave group */
 
     #if ( ipconfigBYTE_ORDER == pdFREERTOS_BIG_ENDIAN )
-        #define ipIGMP_IP_ADDR             0xE0000001UL
+        #define igmpIGMP_IP_ADDR             0xE0000001UL
     #else
-        #define ipIGMP_IP_ADDR             0x010000E0UL
+        #define igmpIGMP_IP_ADDR             0x010000E0UL
     #endif /* ipconfigBYTE_ORDER == pdFREERTOS_BIG_ENDIAN */
 
     #include "pack_struct_start.h"
     struct xIGMP_HEADER
     {
-        uint8_t ucTypeOfMessage;   /**< The IGMP type                     0 + 1 = 1 */
+        uint8_t ucMessageType;     /**< The IGMP type                     0 + 1 = 1 */
         uint8_t ucMaxResponseTime; /**< Maximum time (sec) for responses. 1 + 1 = 2 */
         uint16_t usChecksum;       /**< The checksum of whole IGMP packet 2 + 2 = 4 */
         uint32_t ulGroupAddress;   /**< The multicast group address       4 + 4 = 8 */
@@ -84,14 +84,10 @@
     typedef struct xIGMP_PACKET IGMPPacket_t;
 
     void vIGMP_Init( void );
-    void vModifyMulticastMembership( MulticastAction_t * pxMulticastAction,
-                                     uint8_t bAction );
-    BaseType_t xSendIGMPEvent( void );
     void vHandleIGMP_Event( void );
-    BaseType_t xAddIGMPReportToList( MCastReportData_t * pNewEntry );
+    BaseType_t xAddMulticastReportToList( MCastReportData_t * pNewEntry );
     eFrameProcessingResult_t eProcessIGMPPacket( NetworkBufferDescriptor_t * const pxNetworkBuffer );
     void vProcessMLDPacket( NetworkBufferDescriptor_t * const pxNetworkBuffer );
-    void prvDropMulticastMembership( FreeRTOS_Socket_t * pxSocket ); /* move to Sockets.c as static */
 
 
     #ifdef __cplusplus

source/include/FreeRTOS_IGMP.h

@@ -87,7 +87,7 @@ typedef enum
     eSocketSetDeleteEvent,    /*13: A socket set must be deleted. */
     eSocketOptAddMembership,  /*14: Register a UDP socket to a multicast group. */
     eSocketOptDropMembership, /*15: Unregister a UDP socket from a multicast group. */
-    eIGMPEvent,               /*16: */
+    eMulticastTimerEvent,     /*16: Handles the sending of scheduled IGMP/MLD multicast reports. */
 } eIPEvent_t;
 
 /**
@@ -892,6 +892,15 @@ BaseType_t xIsCallingFromIPTask( void );
 
 #endif /* ipconfigSUPPORT_SELECT_FUNCTION */
 
+#if ( ipconfigSUPPORT_IP_MULTICAST == 1 )
+    struct xMCastGroupDesc;
+    void vModifyMulticastMembership( struct xMCastGroupDesc * pxMulticastAction,
+                                     uint8_t bAction );
+    void vRemoveMulticastReportFromList( IP_Address_t * pxMulticastAddress,
+                                         UBaseType_t xIsIPv6 );
+    BaseType_t xSendMulticastTimerEvent( void );
+#endif /* ipconfigSUPPORT_IP_MULTICAST */
+
 /* Send the network-up event and start the ARP timer. */
 void vIPNetworkUpCalls( struct xNetworkEndPoint * pxEndPoint );