Adds support for receiving IPv4 and IPv6 multicast group

Adds parsing of IGMP and MLD queries.
Sends IGMPv2 and MLDv1 reports on a schedule that is updated based on received IGMP/MLD queries.
Sends unsolicited IGMP and MLD reports on network-up events and on add-membership socket option.
Adds 2 function pointers to the network interface struct that handle adding and removing  multicast MAC addresses.
Adds pxSocket->u.xUDP.xMulticastTTL that can be used for both IPv4 and IPv6
Adds pxSocket->u.xUDP.xMulticastAddress that can be used for both IPv4 and IPv6
Adds socket option defines to cover IPv4, IPv6 as well as source-specific multicast
Adds defines for MLD packets like the Multicast Listener Query and Report
Generates an MLD report for the solicited-node multicast addresses corresponding to all unicast IPv6 addresses

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( ucMulticastTTL ) );
+            #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 +470,20 @@ static void prvProcessIPEventsAndTimers( void )
             /* xQueueReceive() returned because of a normal time-out. */
             break;
 
+            #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+                case eSocketOptAddMembership:
+                case eSocketOptDropMembership:
+                   {
+                       MCastGroupDesc_t * pxMCG = ( MCastGroupDesc_t * ) xReceivedEvent.pvData;
+                       ( void ) vModifyMulticastMembership( pxMCG, xReceivedEvent.eEventType );
+                       break;
+                   }
+
+                case eIGMPEvent:
+                    ( void ) vHandleIGMP_Event();
+                    break;
+            #endif /* ( ipconfigSUPPORT_IP_MULTICAST != 0) */
+
         default:
             /* Should not get here. */
             break;
@@ -526,6 +543,11 @@ 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;
 }
@@ -631,8 +653,76 @@ TaskHandle_t FreeRTOS_GetIPTaskHandle( void )
  */
 void vIPNetworkUpCalls( struct xNetworkEndPoint * pxEndPoint )
 {
+    #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+        MCastReportData_t * pxMRD;
+        IPv6_Type_t xAddressType;
+        MACAddress_t xMACAddress;
+    #endif /* ( ipconfigSUPPORT_IP_MULTICAST != 0 ) */
+
     pxEndPoint->bits.bEndPointUp = pdTRUE_UNSIGNED;
 
+    #if ( ipconfigSUPPORT_IP_MULTICAST != 0 )
+        if( pxEndPoint->bits.bIPv6 == pdTRUE_UNSIGNED )
+        {
+            /* Now that the network is up, pxEndPoint->ipv6_settings should hold the actual address of this
+             * end-point. For unicast addresses, generate the solicited-node multicast address that corresponds
+             * to the address and generate an MLD report for it.
+             * ToDo: Figure out what the proper place is to remove multicast addresses that are no longer valid. For
+             * example when a DHCPv6 lease expires. */
+            xAddressType = xIPv6_GetIPType( &( pxEndPoint->ipv6_settings.xIPAddress ) );
+
+            if( ( xAddressType == eIPv6_LinkLocal ) || ( xAddressType == eIPv6_SiteLocal ) || ( xAddressType == eIPv6_Global ) )
+            {
+                if( NULL != ( pxMRD = ( MCastReportData_t * ) pvPortMalloc( sizeof( MCastReportData_t ) ) ) )
+                {
+                    listSET_LIST_ITEM_OWNER( &( pxMRD->xListItem ), ( void * ) pxMRD );
+                    pxMRD->pxEndPoint = pxEndPoint;
+                    pxMRD->xMCastGroupAddress.xIs_IPv6 = pdTRUE_UNSIGNED;
+
+                    /* Generate the solicited-node multicast address in the form of
+                     * ff02::1:ffnn:nnnn, where nn:nnnn are the last 3 bytes of the IPv6 address. */
+                    pxMRD->xMCastGroupAddress.xIPAddress.xIP_IPv6.ucBytes[ 0 ] = 0xFFU;
+                    pxMRD->xMCastGroupAddress.xIPAddress.xIP_IPv6.ucBytes[ 1 ] = 0x02U;
+                    ( void ) memset( &pxMRD->xMCastGroupAddress.xIPAddress.xIP_IPv6.ucBytes[ 2 ], 0x00, 9 );
+                    pxMRD->xMCastGroupAddress.xIPAddress.xIP_IPv6.ucBytes[ 11 ] = 0x01U;
+                    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 ) )
+                    {
+                        vPortFree( pxMRD );
+                        pxMRD = NULL;
+                    }
+                    else
+                    {
+                        /* The report was consumed, therefore it was added to the list. Tell the network
+                         * driver to begin receiving the associated MAC address */
+                        if( pxEndPoint->pxNetworkInterface && ( pxEndPoint->pxNetworkInterface->pfAddMulticastMAC != NULL ) )
+                        {
+                            xMACAddress.ucBytes[ 0 ] = 0x33;
+                            xMACAddress.ucBytes[ 1 ] = 0x33;
+                            xMACAddress.ucBytes[ 2 ] = 0xFF;
+                            xMACAddress.ucBytes[ 3 ] = pxEndPoint->ipv6_settings.xIPAddress.ucBytes[ 13 ];
+                            xMACAddress.ucBytes[ 4 ] = pxEndPoint->ipv6_settings.xIPAddress.ucBytes[ 14 ];
+                            xMACAddress.ucBytes[ 5 ] = pxEndPoint->ipv6_settings.xIPAddress.ucBytes[ 15 ];
+                            pxEndPoint->pxNetworkInterface->pfAddMulticastMAC( xMACAddress.ucBytes );
+                        }
+                    }
+                }
+            }
+        } /* if( pxEndPoint->bits.bIPv6 == pdTRUE_UNSIGNED ) */
+
+        /* Reschedule all multicast reports associated with this end-point.
+         * /* Note: countdown is in increments of ipIGMP_TIMER_PERIOD_MS. It's a good idea to spread out all reports a little.
+         * 200 to 500ms ( xMaxCountdown of 2 - 5 ) should be a good happy medium. If the network we just connected to has a IGMP/MLD querier,
+         * they will soon ask us for reports anyways, so sending these unsolicited reports is not required. It simply enhances the user
+         * experience by shortening the time it takes before we begin receiving the multicasts that we care for. */
+        /* _EP_: vRescheduleAllMulticastReports() is NOT declared in header files because I don't want to expose it to the user */
+        extern void vRescheduleAllMulticastReports( NetworkEndPoint_t * pxEndPoint,
+                                                    BaseType_t xMaxCountdown );
+        vRescheduleAllMulticastReports( pxEndPoint, 5 );
+    #endif /* ( ipconfigSUPPORT_IP_MULTICAST != 0 ) */
+
     #if ( ipconfigUSE_NETWORK_EVENT_HOOK == 1 )
     #if ( ipconfigIPv4_BACKWARD_COMPATIBLE == 1 )
         {
@@ -1976,6 +2066,13 @@ 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 when all network interfaces are initialised
@@ -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

@@ -386,7 +386,7 @@ BaseType_t xIsIPv6AllowedMulticast( const IPv6_Address_t * pxIPAddress )
 /**
  * @brief Compares 2 IPv6 addresses and checks if the one
  * on the left can handle the one on right. Note that 'xCompareIPv6_Address' will also check if 'pxRight' is
- * the special unicast address: ff02::1:ffnn:nnnn, where nn:nnnn are
+ * the special multicast address: ff02::1:ffnn:nnnn, where nn:nnnn are
  * the last 3 bytes of the IPv6 address.
  *
  * @param[in] pxLeft First IP address.
@@ -410,6 +410,7 @@ BaseType_t xCompareIPv6_Address( const IPv6_Address_t * pxLeft,
         ( pxRight->ucBytes[ 12 ] == 0xffU ) )
     {
         /* This is an LLMNR address. */
+        /* _EP_: I don't think this is LLMNR. Did someone mean to say "the solicited-node multicast address" ? */
         xResult = memcmp( &( pxLeft->ucBytes[ 13 ] ), &( pxRight->ucBytes[ 13 ] ), 3 );
     }
     else

source/FreeRTOS_IPv6.c

@@ -1112,6 +1112,26 @@
                             break;
                     #endif /* ( ipconfigUSE_RA != 0 ) */
 
+                    #if ( ipconfigSUPPORT_IP_MULTICAST == 1 )
+                        case ipICMP_MULTICAST_LISTENER_QUERY:
+                        case ipICMP_MULTICAST_LISTENER_REPORT_V1:
+                        case ipICMP_MULTICAST_LISTENER_REPORT_V2:
+
+                            /* Note: prvProcessIPPacket() stripped the extension headers, so this packet struct is defined without them and they cannot be checked.
+                             * per RFC, MLD packets must use the RouterAlert option in a Hop By Hop extension header. */
+                            /* All MLD packets are at least as large as a v1 query packet. */
+                            uxNeededSize = ( size_t ) ( ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv6_HEADER + ipSIZE_OF_ICMPv6_HEADER );
+
+                            if( uxNeededSize > pxNetworkBuffer->xDataLength )
+                            {
+                                FreeRTOS_printf( ( "Too small\n" ) );
+                                break;
+                            }
+
+                            vProcessMLDPacket( pxNetworkBuffer );
+                            break;
+                    #endif /* if ( ipconfigSUPPORT_IP_MULTICAST == 1 ) */
+
                 default:
                     /* All possible values are included here above. */
                     break;