Initialising the TCP/IP Stack
Part of the FreeRTOS-Plus-TCP Networking Tutorial

This page describes FreeRTOS_IPInit_Multi() and the callback function that gets invoked when 'network up' and 'network down' events occur.

Before calling the FreeRTOS_IPInit_Multi() function, the application must add the Network-Interface and at least one of the End-Points corresponding to a network interface. A Network-Interface is the driver of the EMAC + PHY ( or a WiFi adapter ). An End-Point is a set of network parameters: an IP-address, MAC-address, Gateway, DNS, and so on. There can be multiple Interfaces, each one owning one or more end-points.

The function used to initialise an interface is px${port_name}_FillInterfaceDescriptor (for example, pxSAM_FillInterfaceDescriptor). The function used to add an Endpoint is FreeRTOS_FillEndPoint or FreeRTOS_FillEndPoint_IPv6.

FreeRTOS_IPInit_Multi() creates the FreeRTOS-Plus-TCP RTOS task. The FreeRTOS-Plus-TCP task configures and initialises the network interface. If ipconfigUSE_NETWORK_EVENT_HOOK is set to 1 in FreeRTOSIPConfig.h then the TCP/IP stack will call the vApplicationIPNetworkEventHook_Multi() callback function when the network is ready for use.

Two examples are provided below. The first demonstrates FreeRTOS_IPInit_Multi(). The second demonstrates vApplicationIPNetworkEventHook_Multi().

IPv4 Example:

/* The MAC address array is not declared const as the MAC address will


   normally be read from an EEPROM and not hard coded (in real deployed


   applications).*/

static uint8_t ucMACAddress[ 6 ] = { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55 };



/* Define the network addressing.  These parameters will be used if either


   ipconfigUDE_DHCP is 0 or if ipconfigUSE_DHCP is 1 but DHCP auto configuration


   failed. */

static const uint8_t ucIPAddress[ 4 ] = { 10, 10, 10, 200 };

static const uint8_t ucNetMask[ 4 ] = { 255, 0, 0, 0 };

static const uint8_t ucGatewayAddress[ 4 ] = { 10, 10, 10, 1 };



/* The following is the address of an OpenDNS server. */

static const uint8_t ucDNSServerAddress[ 4 ] = { 208, 67, 222, 222 };



int main( void )

{



    /* Initialise the interface descriptor for WinPCap for example. */

    pxWinPcap_FillInterfaceDescriptor( 0, &( xInterfaces[ 0 ] ) );

    

    FreeRTOS_FillEndPoint( &( xInterfaces[ 0 ] ), &( xEndPoints[ 0 ] ), ucIPAddress,

            ucNetMask, ucGatewayAddress, ucDNSServerAddress, ucMACAddress );

    #if ( ipconfigUSE_DHCP != 0 )

    {

        /* End-point 0 wants to use DHCPv4. */

        xEndPoints[ 0 ].bits.bWantDHCP = pdTRUE;

    }

    #endif /* ( ipconfigUSE_DHCP != 0 ) */

    

    /* Initialise the RTOS's TCP/IP stack.  The tasks that use the network


       are created in the vApplicationIPNetworkEventHook() hook function


       below.  The hook function is called when the network connects. */                    

     FreeRTOS_IPInit_Multi();



    /*


     * Other RTOS tasks can be created here.


     */



    /* Start the RTOS scheduler. */

    vTaskStartScheduler();



    /* If all is well, the scheduler will now be running, and the following


       line will never be reached.  If the following line does execute, then


       there was insufficient FreeRTOS heap memory available for the idle and/or


       timer tasks to be created. */

    for( ;; );

}

Example use of the FreeRTOS_IPInit_Multi() API function

void vApplicationIPNetworkEventHook_Multi( eIPCallbackEvent_t eNetworkEvent,

                                           struct xNetworkEndPoint * pxEndPoint )

{

static BaseType_t xTasksAlreadyCreated = pdFALSE;



    /* Both eNetworkUp and eNetworkDown events can be processed here. */

    if( eNetworkEvent == eNetworkUp )

    {

        /* Create the tasks that use the TCP/IP stack if they have not already


        been created. */

        if( xTasksAlreadyCreated == pdFALSE )

        {

            /*


             * For convenience, tasks that use FreeRTOS-Plus-TCP can be created here


             * to ensure they are not created before the network is usable.


             */



            xTasksAlreadyCreated = pdTRUE;

        }

    }

    /* Print out the network configuration, which may have come from a DHCP


     * server. */

    showEndPoint( pxEndPoint );

}

Example use of the vApplicationIPNetworkEventHook_Multi()definition

IPv6 Example:

/* The MAC address array is not declared const as the MAC address will


   normally be read from an EEPROM and not hard coded (in real deployed


   applications).*/

static uint8_t ucMACAddress[ 6 ] = { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55 };



int main( void )

{

    IPv6_Address_t xIPAddress;

    IPv6_Address_t xPrefix;

    IPv6_Address_t xGateWay;



    /* Initialise the interface descriptor for WinPCap for example. */

    pxWinPcap_FillInterfaceDescriptor( 0, &( xInterfaces[ 0 ] ) );

    

    /* Add Endpoint - IPv6 needs minimum 2 EndPoints on the same network interface */

    

    /*


     *     End-point-1 : public


     *     Network: 2001:470:ed44::/64


     *     IPv6   : 2001:470:ed44::4514:89d5:4589:8b79/128


     *     Gateway: fe80::ba27:ebff:fe5a:d751  // obtained from Router Advertisement


     */

    FreeRTOS_inet_pton6( "2001:470:ed44::", xPrefix.ucBytes );

    FreeRTOS_CreateIPv6Address( &xIPAddress, &xPrefix, 64, pdTRUE );

    

    FreeRTOS_inet_pton6( "fe80::ba27:ebff:fe5a:d751", xGateWay.ucBytes );

    #if ( ipconfigUSE_RA != 0 )

    {

         /* End-point 1 wants to use Router Advertisement */

         xEndPoints[ 0 ].bits.bWantRA = pdTRUE;

    }

    #endif /* #if( ipconfigUSE_RA != 0 ) */

    #if ( ipconfigUSE_DHCPv6 != 0 )

    {

          /* End-point 1 wants to use DHCPv6. */

          xEndPoints[ 0 ].bits.bWantDHCP = pdTRUE;

    }

    

    FreeRTOS_FillEndPoint_IPv6( &( xInterfaces[ 0 ] ),

                                   &( xEndPoints[ 0] ),

                                   &( xIPAddress ),

                                   &( xPrefix ),

                                   64uL, /* Prefix length. */

                                   &( xGateWay ),

                                   NULL, /* pxDNSServerAddress: Not used yet. */

                                   ucMACAddress );

    FreeRTOS_inet_pton6( "2001:4860:4860::8888", xEndPoints[ 0 ].ipv6_settings.xDNSServerAddresses[ 0 ].ucBytes );

    FreeRTOS_inet_pton6( "fe80::1", xEndPoints[ 0 ].ipv6_settings.xDNSServerAddresses[ 1 ].ucBytes );

    FreeRTOS_inet_pton6( "2001:4860:4860::8888", xEndPoints[ 0 ].ipv6_defaults.xDNSServerAddresses[ 0 ].ucBytes );

    FreeRTOS_inet_pton6( "fe80::1", xEndPoints[ 0 ].ipv6_defaults.xDNSServerAddresses[ 1 ].ucBytes );

    

    /*


     *     End-point-2: private


     *     Network: fe80::/10 (link-local)


     *     IPv6   : fe80::d80e:95cc:3154:b76a/128


     *     Gateway: -


     */

    

     FreeRTOS_inet_pton6( "fe80::", xPrefix.ucBytes );

     FreeRTOS_inet_pton6( "fe80::7009", xIPAddress.ucBytes );



     #if ( ipconfigUSE_DHCPv6 != 0 )

    {

          /* End-point 2 wants to use DHCPv6. */

          xEndPoints[ 1 ].bits.bWantDHCP = pdTRUE;

    }

     

     FreeRTOS_FillEndPoint_IPv6(

                    &( xInterfaces[ 0 ] ),

                    &( xEndPoints[ 1 ] ),

                    &( xIPAddress ),

                    &( xPrefix ),

                    10U,  /* Prefix length. */

                    NULL, /* No gateway */

                    NULL, /* pxDNSServerAddress: Not used yet. */

                    ucMACAddress );

    

    /* Initialise the RTOS's TCP/IP stack.  The tasks that use the network


       are created in the vApplicationIPNetworkEventHook() hook function


       below.  The hook function is called when the network connects. */                 

    FreeRTOS_IPInit_Multi();



    /*


     * Other RTOS tasks can be created here.


     */



    /* Start the RTOS scheduler. */

    vTaskStartScheduler();



    /* If all is well, the scheduler will now be running, and the following


    line will never be reached.  If the following line does execute, then


    there was insufficient FreeRTOS heap memory available for the idle and/or


    timer tasks to be created. */

    for( ;; );

}

Example use of the FreeRTOS_IPInit_Multi() API function

void vApplicationIPNetworkEventHook_Multi( eIPCallbackEvent_t eNetworkEvent,

                                           struct xNetworkEndPoint * pxEndPoint )

{

static BaseType_t xTasksAlreadyCreated = pdFALSE;



    /* Both eNetworkUp and eNetworkDown events can be processed here. */

    if( eNetworkEvent == eNetworkUp )

    {

        /* Create the tasks that use the TCP/IP stack if they have not already


           been created. */

        if( xTasksAlreadyCreated == pdFALSE )

        {

            /*


             * For convenience, tasks that use FreeRTOS-Plus-TCP can be created here


             * to ensure they are not created before the network is usable.


             */



            xTasksAlreadyCreated = pdTRUE;

        }

    }

    

    /* Print out the network configuration, which may have come from a DHCP


     * server. */

    showEndPoint( pxEndPoint );

}

Example use of the vApplicationIPNetworkEventHook_Multi()definition

Quality RTOS & Embedded Software Download FreeRTOS Menu

Initialising the TCP/IP Stack Part of the FreeRTOS-Plus-TCP Networking Tutorial

Quality RTOS & Embedded Software

Download FreeRTOS
Menu

Initialising the TCP/IP Stack
Part of the FreeRTOS-Plus-TCP Networking Tutorial