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/*
* FreeRTOS+UDP V1.0.4
* Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/* Standard includes. */
#include <stdint.h>
/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "timers.h"
/* FreeRTOS+UDP includes. */
#include "FreeRTOS_UDP_IP.h"
#include "FreeRTOS_IP_Private.h"
#include "FreeRTOS_DHCP.h"
#include "FreeRTOS_Sockets.h"
#include "NetworkInterface.h"
#include "IPTraceMacroDefaults.h"
/* Exclude the entire file if DHCP is not enabled. */
#if ipconfigUSE_DHCP != 0
#if ( ipconfigUSE_DHCP != 0 ) && ( ipconfigNETWORK_MTU < 586 )
/* DHCP must be able to receive an options field of 312 bytes, the fixed
part of the DHCP packet is 240 bytes, and the IP/UDP headers take 28 bytes. */
#error ipconfigNETWORK_MTU needs to be at least 586 to use DHCP (588 if ipconfigCAN_FRAGMENT_OUTGOING_PACKETS is set to 1)
#endif
/* Parameter widths in the DHCP packet. */
#define dhcpCLIENT_HARDWARE_ADDRESS_LENGTH 16
#define dhcpSERVER_HOST_NAME_LENGTH 64
#define dhcpBOOT_FILE_NAME_LENGTH 128
/* Timer parameters. Windows simulator times are much shorter because simulated
time is not real time. */
#ifdef _WINDOWS_
#define dhcpINITIAL_DHCP_TX_PERIOD ( 100 / portTICK_RATE_MS )
#define dhcpINITIAL_TIMER_PERIOD ( 10 / portTICK_RATE_MS )
#define dhcpMAX_TIME_TO_WAIT_FOR_ACK ( 200 / portTICK_RATE_MS )
#else
#define dhcpINITIAL_DHCP_TX_PERIOD ( 5000 / portTICK_RATE_MS )
#define dhcpINITIAL_TIMER_PERIOD ( 250 / portTICK_RATE_MS )
#define dhcpMAX_TIME_TO_WAIT_FOR_ACK ( 5000 / portTICK_RATE_MS )
#endif /* _WINDOWS_ */
/* Codes of interest found in the DHCP options field. */
#define dhcpSUBNET_MASK_OPTION_CODE ( 1 )
#define dhcpGATEWAY_OPTION_CODE ( 3 )
#define hdcpDNS_SERVER_OPTIONS_CODE ( 6 )
#define dhcpMESSAGE_TYPE_OPTION_CODE ( 53 )
#define dhcpLEASE_TIME_OPTION_CODE ( 51 )
#define dhcpCLIENT_IDENTIFIER_OPTION_CODE ( 61 )
#define dhcpPARAMETER_REQUEST_OPTION_CODE ( 55 )
#define dhcpREQUEST_IP_ADDRESS_OPTION_CODE ( 50 )
#define dhcpSERVER_IP_ADDRESS_OPTION_CODE ( 54 )
/* The four DHCP message types of interest. */
#define dhcpMESSAGE_TYPE_DISCOVER ( 1 )
#define dhcpMESSAGE_TYPE_OFFER ( 2 )
#define dhcpMESSAGE_TYPE_REQUEST ( 3 )
#define dhcpMESSAGE_TYPE_ACK ( 5 )
#define dhcpMESSAGE_TYPE_NACK ( 6 )
/* Offsets into the transmitted DHCP options fields at which various parameters
are located. */
#define dhcpCLIENT_IDENTIFIER_OFFSET ( 5 )
#define dhcpREQUESTED_IP_ADDRESS_OFFSET ( 13 )
#define dhcpDHCP_SERVER_IP_ADDRESS_OFFSET ( 19 )
/* Values used in the DHCP packets. */
#define dhcpREQUEST_OPCODE ( 1 )
#define dhcpREPLY_OPCODE ( 2 )
#define dhcpADDRESS_TYPE_ETHERNET ( 1 )
#define dhcpETHERNET_ADDRESS_LENGTH ( 6 )
/* If a lease time is not received, use the default of two days. */
#define dhcpDEFAULT_LEASE_TIME ( ( 48UL * 60UL * 60UL * 1000UL ) / portTICK_RATE_MS ) /* 48 hours in ticks. */
/* Don't allow the lease time to be too short. */
#define dhcpMINIMUM_LEASE_TIME ( 60000UL / portTICK_RATE_MS ) /* 60 seconds in ticks. */
/* Marks the end of the variable length options field in the DHCP packet. */
#define dhcpOPTION_END_BYTE 0xff
/* Offset into a DHCP message at which the first byte of the options is
located. */
#define dhcpFIRST_OPTION_BYTE_OFFSET ( 0xf0 )
/* When walking the variable length options field, the following value is used
to ensure the walk has not gone past the end of the valid options. 2 bytes is
made up of the length byte, and minimum one byte value. */
#define dhcpMAX_OPTION_LENGTH_OF_INTEREST ( 2L )
/* Standard DHCP port numbers and magic cookie value. */
#if( ipconfigBYTE_ORDER == FREERTOS_LITTLE_ENDIAN )
#define dhcpCLIENT_PORT 0x4400
#define dhcpSERVER_PORT 0x4300
#define dhcpCOOKIE 0x63538263
#define dhcpBROADCAST 0x0080
#else
#define dhcpCLIENT_PORT 0x0044
#define dhcpSERVER_PORT 0x0043
#define dhcpCOOKIE 0x63825363
#define dhcpBROADCAST 0x8000
#endif /* ipconfigBYTE_ORDER */
#include "pack_struct_start.h"
struct xDHCPMessage
{
uint8_t ucOpcode;
uint8_t ucAddressType;
uint8_t ucAddressLength;
uint8_t ucHops;
uint32_t ulTransactionID;
uint16_t usElapsedTime;
uint16_t usFlags;
uint32_t ulClientIPAddress_ciaddr;
uint32_t ulYourIPAddress_yiaddr;
uint32_t ulServerIPAddress_siaddr;
uint32_t ulRelayAgentIPAddress_giaddr;
uint8_t ucClientHardwareAddress[ dhcpCLIENT_HARDWARE_ADDRESS_LENGTH ];
uint8_t ucServerHostName[ dhcpSERVER_HOST_NAME_LENGTH ];
uint8_t ucBootFileName[ dhcpBOOT_FILE_NAME_LENGTH ];
uint32_t ulDHCPCookie;
uint8_t ucFirstOptionByte;
}
#include "pack_struct_end.h"
typedef struct xDHCPMessage xDHCPMessage_t;
/* DHCP state machine states. */
typedef enum
{
eWaitingSendFirstDiscover = 0, /* Initial state. Send a discover the first time it is called, and reset all timers. */
eWaitingOffer, /* Either resend the discover, or, if the offer is forthcoming, send a request. */
eWaitingAcknowledge, /* Either resend the request. */
eLeasedAddress, /* Resend the request at the appropriate time to renew the lease. */
eNotUsingLeasedAddress /* DHCP failed, and a default IP address is being used. */
} eDHCPState_t;
/*
* Generate a DHCP discover message and send it on the DHCP socket.
*/
static void prvSendDHCPDiscover( xMACAddress_t *pxMACAddress );
/*
* Interpret message received on the DHCP socket.
*/
static BaseType_t prvProcessDHCPReplies( uint8_t ucExpectedMessageType, xMACAddress_t *pxMACAddress, xNetworkAddressingParameters_t *pxNetworkAddressing );
/*
* Generate a DHCP request packet, and send it on the DHCP socket.
*/
static void prvSendDHCPRequest( xMACAddress_t *pxMACAddress );
/*
* Prepare to start a DHCP transaction. This initialises some state variables
* and creates the DHCP socket if necessary.
*/
static void prvInitialiseDHCP( void );
/*
* Creates the part of outgoing DHCP messages that are common to all outgoing
* DHCP messages.
*/
static uint8_t *prvCreatePartDHCPMessage( struct freertos_sockaddr *pxAddress, xMACAddress_t *pxMACAddress, uint8_t ucOpcode, const uint8_t * const pucOptionsArray, size_t xOptionsArraySize );
/*
* Create the DHCP socket, if it has not been created already.
*/
static void prvCreateDHCPSocket( void );
/*-----------------------------------------------------------*/
/* The timer used to drive the DHCP state machine. */
static xTimerHandle xDHCPTimer = NULL;
/* The UDP socket used for all incoming and outgoing DHCP traffic. */
static xSocket_t xDHCPSocket = NULL;
/* Hold information in between steps in the DHCP state machine. */
static uint32_t ulTransactionId = 0UL, ulOfferedIPAddress = 0UL, ulDHCPServerAddress = 0UL, ulLeaseTime = 0;
/* Hold information on the current timer state. */
static TickType_t xDHCPTxTime = 0x00, xDHCPTxPeriod = 0x00;
/* Maintains the DHCP state machine state. */
static eDHCPState_t eDHCPState = eWaitingSendFirstDiscover;
/*-----------------------------------------------------------*/
void vDHCPProcess( BaseType_t xReset, xMACAddress_t *pxMACAddress, uint32_t *pulIPAddress, xNetworkAddressingParameters_t *pxNetworkAddressing )
{
if( xReset != pdFALSE )
{
eDHCPState = eWaitingSendFirstDiscover;
}
switch( eDHCPState )
{
case eWaitingSendFirstDiscover :
/* Initial state. Create the DHCP socket, timer, etc. if they
have not already been created. */
prvInitialiseDHCP();
*pulIPAddress = 0UL;
/* Send the first discover request. */
if( xDHCPSocket != NULL )
{
xDHCPTxTime = xTaskGetTickCount();
prvSendDHCPDiscover( pxMACAddress );
eDHCPState = eWaitingOffer;
}
break;
case eWaitingOffer :
/* Look for offers coming in. */
if( prvProcessDHCPReplies( dhcpMESSAGE_TYPE_OFFER, pxMACAddress, pxNetworkAddressing ) == pdPASS )
{
/* An offer has been made, generate the request. */
xDHCPTxTime = xTaskGetTickCount();
xDHCPTxPeriod = dhcpINITIAL_DHCP_TX_PERIOD;
prvSendDHCPRequest( pxMACAddress );
eDHCPState = eWaitingAcknowledge;
}
else
{
/* Is it time to send another Discover? */
if( ( xTaskGetTickCount() - xDHCPTxTime ) > xDHCPTxPeriod )
{
/* Increase the time period, and if it has not got to the
point of giving up - send another discovery. */
xDHCPTxPeriod <<= 1;
if( xDHCPTxPeriod <= ipconfigMAXIMUM_DISCOVER_TX_PERIOD )
{
ulTransactionId++;
xDHCPTxTime = xTaskGetTickCount();
prvSendDHCPDiscover( pxMACAddress );
}
else
{
/* Revert to static IP address. */
taskENTER_CRITICAL();
{
*pulIPAddress = pxNetworkAddressing->ulDefaultIPAddress;
iptraceDHCP_REQUESTS_FAILED_USING_DEFAULT_IP_ADDRESS( pxNetworkAddressing->ulDefaultIPAddress );
}
taskEXIT_CRITICAL();
eDHCPState = eNotUsingLeasedAddress;
xTimerStop( xDHCPTimer, ( TickType_t ) 0 );
#if ipconfigUSE_NETWORK_EVENT_HOOK == 1
{
vApplicationIPNetworkEventHook( eNetworkUp );
}
#endif
/* Static configuration is being used, so the network is now up. */
#if ipconfigFREERTOS_PLUS_NABTO == 1
{
/* Return value is used in configASSERT() inside the
function. */
( void ) xStartNabtoTask();
}
#endif /* ipconfigFREERTOS_PLUS_NABTO */
/* Close socket to ensure packets don't queue on it. */
FreeRTOS_closesocket( xDHCPSocket );
xDHCPSocket = NULL;
}
}
}
break;
case eWaitingAcknowledge :
/* Look for acks coming in. */
if( prvProcessDHCPReplies( dhcpMESSAGE_TYPE_ACK, pxMACAddress, pxNetworkAddressing ) == pdPASS )
{
/* DHCP completed. The IP address can now be used, and the
timer set to the lease timeout time. */
*pulIPAddress = ulOfferedIPAddress;
eDHCPState = eLeasedAddress;
#if ipconfigUSE_NETWORK_EVENT_HOOK == 1
{
vApplicationIPNetworkEventHook( eNetworkUp );
}
#endif
/* Static configuration is being used, so the network is now
up. */
#if ipconfigFREERTOS_PLUS_NABTO == 1
{
/* Return value is used in configASSERT() inside the
function. */
( void ) xStartNabtoTask();
}
#endif /* ipconfigFREERTOS_PLUS_NABTO */
/* Close socket to ensure packets don't queue on it. */
FreeRTOS_closesocket( xDHCPSocket );
xDHCPSocket = NULL;
if( ulLeaseTime == 0UL )
{
ulLeaseTime = dhcpDEFAULT_LEASE_TIME;
}
else if( ulLeaseTime < dhcpMINIMUM_LEASE_TIME )
{
ulLeaseTime = dhcpMINIMUM_LEASE_TIME;
}
else
{
/* The lease time is already valid. */
}
xTimerChangePeriod( xDHCPTimer, ulLeaseTime, portMAX_DELAY );
}
else
{
/* Is it time to send another Discover? */
if( ( xTaskGetTickCount() - xDHCPTxTime ) > xDHCPTxPeriod )
{
/* Increase the time period, and if it has not got to the
point of giving up - send another request. */
xDHCPTxPeriod <<= 1;
if( xDHCPTxPeriod <= ipconfigMAXIMUM_DISCOVER_TX_PERIOD )
{
xDHCPTxTime = xTaskGetTickCount();
prvSendDHCPRequest( pxMACAddress );
}
else
{
/* Give up, start again. */
eDHCPState = eWaitingSendFirstDiscover;
}
}
}
break;
case eLeasedAddress :
/* Resend the request at the appropriate time to renew the lease. */
prvCreateDHCPSocket();
if( xDHCPSocket != NULL )
{
xDHCPTxTime = xTaskGetTickCount();
xDHCPTxPeriod = dhcpINITIAL_DHCP_TX_PERIOD;
prvSendDHCPRequest( pxMACAddress );
eDHCPState = eWaitingAcknowledge;
}
xTimerChangePeriod( xDHCPTimer, dhcpINITIAL_TIMER_PERIOD, portMAX_DELAY );
break;
case eNotUsingLeasedAddress:
xTimerStop( xDHCPTimer, ( TickType_t ) 0 );
break;
}
}
/*-----------------------------------------------------------*/
static void prvCreateDHCPSocket( void )
{
struct freertos_sockaddr xAddress;
BaseType_t xReturn;
TickType_t xTimeoutTime = 0;
/* Create the socket, if it has not already been created. */
if( xDHCPSocket == NULL )
{
xDHCPSocket = FreeRTOS_socket( FREERTOS_AF_INET, FREERTOS_SOCK_DGRAM, FREERTOS_IPPROTO_UDP );
configASSERT( ( xDHCPSocket != FREERTOS_INVALID_SOCKET ) );
/* Ensure the Rx and Tx timeouts are zero as the DHCP executes in the
context of the IP task. */
FreeRTOS_setsockopt( xDHCPSocket, 0, FREERTOS_SO_RCVTIMEO, ( void * ) &xTimeoutTime, sizeof( TickType_t ) );
FreeRTOS_setsockopt( xDHCPSocket, 0, FREERTOS_SO_SNDTIMEO, ( void * ) &xTimeoutTime, sizeof( TickType_t ) );
/* Bind to the standard DHCP client port. */
xAddress.sin_port = dhcpCLIENT_PORT;
xReturn = FreeRTOS_bind( xDHCPSocket, &xAddress, sizeof( xAddress ) );
configASSERT( xReturn == 0 );
/* Remove compiler warnings if configASSERT() is not defined. */
( void ) xReturn;
}
}
/*-----------------------------------------------------------*/
static void prvInitialiseDHCP( void )
{
extern void vIPFunctionsTimerCallback( xTimerHandle xTimer );
/* Initialise the parameters that will be set by the DHCP process. */
if( ulTransactionId == 0 )
{
ulTransactionId = ipconfigRAND32();
}
else
{
ulTransactionId++;
}
ulOfferedIPAddress = 0UL;
ulDHCPServerAddress = 0UL;
xDHCPTxPeriod = dhcpINITIAL_DHCP_TX_PERIOD;
/* Create the DHCP socket if it has not already been created. */
prvCreateDHCPSocket();
if( xDHCPTimer == NULL )
{
xDHCPTimer = xTimerCreate( "DHCP", dhcpINITIAL_TIMER_PERIOD, pdTRUE, ( void * ) eDHCPEvent, vIPFunctionsTimerCallback );
configASSERT( xDHCPTimer );
xTimerStart( xDHCPTimer, portMAX_DELAY );
}
else
{
xTimerChangePeriod( xDHCPTimer, dhcpINITIAL_TIMER_PERIOD, portMAX_DELAY );
}
}
/*-----------------------------------------------------------*/
static BaseType_t prvProcessDHCPReplies( uint8_t ucExpectedMessageType, xMACAddress_t *pxMACAddress, xNetworkAddressingParameters_t *pxNetworkAddressing )
{
uint8_t *pucUDPPayload, *pucLastByte;
struct freertos_sockaddr xClient;
uint32_t xClientLength = sizeof( xClient );
int32_t lBytes;
xDHCPMessage_t *pxDHCPMessage;
uint8_t *pucByte, ucOptionCode, ucLength;
uint32_t ulProcessed;
BaseType_t xReturn = pdFALSE;
const uint32_t ulMandatoryOptions = 2; /* DHCP server address, and the correct DHCP message type must be present in the options. */
lBytes = FreeRTOS_recvfrom( xDHCPSocket, ( void * ) &pucUDPPayload, 0, FREERTOS_ZERO_COPY, &xClient, &xClientLength );
if( lBytes > 0 )
{
/* Map a DHCP structure onto the received data. */
pxDHCPMessage = ( xDHCPMessage_t * ) ( pucUDPPayload );
/* Sanity check. */
if( ( pxDHCPMessage->ulDHCPCookie == dhcpCOOKIE ) && ( pxDHCPMessage->ucOpcode == dhcpREPLY_OPCODE ) && ( pxDHCPMessage->ulTransactionID == ulTransactionId ) )
{
if( memcmp( ( void * ) &( pxDHCPMessage->ucClientHardwareAddress ), ( void * ) pxMACAddress, sizeof( xMACAddress_t ) ) == 0 )
{
/* None of the essential options have been processed yet. */
ulProcessed = 0;
/* Walk through the options until the dhcpOPTION_END_BYTE byte
is found, taking care not to walk off the end of the options. */
pucByte = &( pxDHCPMessage->ucFirstOptionByte );
pucLastByte = &( pucUDPPayload[ lBytes - dhcpMAX_OPTION_LENGTH_OF_INTEREST ] );
while( ( *pucByte != dhcpOPTION_END_BYTE ) && ( pucByte < pucLastByte ) )
{
ucOptionCode = *pucByte;
pucByte++;
ucLength = *pucByte;
pucByte++;
switch( ucOptionCode )
{
case dhcpMESSAGE_TYPE_OPTION_CODE :
if( *pucByte == ucExpectedMessageType )
{
/* The message type is the message type the
state machine is expecting. */
ulProcessed++;
}
else if( *pucByte == dhcpMESSAGE_TYPE_NACK )
{
if( ucExpectedMessageType == dhcpMESSAGE_TYPE_ACK )
{
/* Start again. */
eDHCPState = eWaitingSendFirstDiscover;
}
}
else
{
/* Don't process other message types. */
}
break;
case dhcpSUBNET_MASK_OPTION_CODE :
if( ucLength == sizeof( uint32_t ) )
{
memcpy( ( void * ) &( pxNetworkAddressing->ulNetMask ), ( void * ) pucByte, ( size_t ) ucLength );
}
break;
case dhcpGATEWAY_OPTION_CODE :
if( ucLength == sizeof( uint32_t ) )
{
/* ulProcessed is not incremented in this case
because the gateway is not essential. */
memcpy( ( void * ) &( pxNetworkAddressing->ulGatewayAddress ), ( void * ) pucByte, ( size_t ) ucLength );
}
break;
case hdcpDNS_SERVER_OPTIONS_CODE :
/* ulProcessed is not incremented in this case
because the DNS server is not essential. Only the
first DNS server address is taken. */
memcpy( ( void * ) &( pxNetworkAddressing->ulDNSServerAddress ), ( void * ) pucByte, sizeof( uint32_t ) );
break;
case dhcpSERVER_IP_ADDRESS_OPTION_CODE :
if( ucLength == sizeof( uint32_t ) )
{
if( ucExpectedMessageType == dhcpMESSAGE_TYPE_OFFER )
{
/* Offers state the replying server. */
ulProcessed++;
memcpy( ( void * ) &ulDHCPServerAddress, ( void * ) pucByte, ( size_t ) ucLength );
}
else
{
/* The ack must come from the expected server. */
if( memcmp( ( void * ) &ulDHCPServerAddress, ( void * ) pucByte, ( size_t ) ucLength ) == 0 )
{
ulProcessed++;
}
}
}
break;
case dhcpLEASE_TIME_OPTION_CODE :
if( ucLength == sizeof( &ulLeaseTime ) )
{
/* ulProcessed is not incremented in this case
because the lease time is not essential. */
memcpy( ( void * ) &ulLeaseTime, ( void * ) pucByte, ( size_t ) ucLength );
ulLeaseTime = FreeRTOS_ntohl( ulLeaseTime );
/* Convert the lease time to milliseconds
(*1000) then ticks (/portTICK_RATE_MS). */
ulLeaseTime *= ( 1000UL / portTICK_RATE_MS );
/* Divide the lease time to ensure a renew
request is sent before the lease actually
expires. */
ulLeaseTime >>= 1UL;
}
break;
default :
/* Not interested in this field. */
break;
}
/* Jump over the data to find the next option code. */
if( ucLength == 0 )
{
break;
}
else
{
pucByte += ucLength;
}
}
/* Were all the mandatory options received? */
if( ulProcessed == ulMandatoryOptions )
{
ulOfferedIPAddress = pxDHCPMessage->ulYourIPAddress_yiaddr;
xReturn = pdPASS;
}
}
}
FreeRTOS_ReleaseUDPPayloadBuffer( ( void * ) pucUDPPayload );
}
return xReturn;
}
/*-----------------------------------------------------------*/
static uint8_t *prvCreatePartDHCPMessage( struct freertos_sockaddr *pxAddress, xMACAddress_t *pxMACAddress, uint8_t ucOpcode, const uint8_t * const pucOptionsArray, size_t xOptionsArraySize )
{
xDHCPMessage_t *pxDHCPMessage;
const size_t xRequiredBufferSize = sizeof( xDHCPMessage_t ) + xOptionsArraySize;
uint8_t *pucUDPPayloadBuffer;
static uint8_t ucUseBroadcastFlag = pdFALSE;
/* Get a buffer. This uses a maximum delay, but the delay will be capped
to ipconfigMAX_SEND_BLOCK_TIME_TICKS so the return value still needs to be
test. */
do
{
}while( ( pucUDPPayloadBuffer = ( uint8_t * ) FreeRTOS_GetUDPPayloadBuffer( xRequiredBufferSize, portMAX_DELAY ) ) == NULL );
pxDHCPMessage = ( xDHCPMessage_t * ) pucUDPPayloadBuffer;
/* Most fields need to be zero. */
memset( ( void * ) pxDHCPMessage, 0x00, sizeof( xDHCPMessage_t ) );
/* Create the message. */
pxDHCPMessage->ucOpcode = ucOpcode;
pxDHCPMessage->ucAddressType = dhcpADDRESS_TYPE_ETHERNET;
pxDHCPMessage->ucAddressLength = dhcpETHERNET_ADDRESS_LENGTH;
pxDHCPMessage->ulTransactionID = ulTransactionId;
pxDHCPMessage->ulDHCPCookie = dhcpCOOKIE;
/* For maximum possibility of success, alternate between broadcast and non
broadcast. */
ucUseBroadcastFlag = !ucUseBroadcastFlag;
if( ucUseBroadcastFlag == pdTRUE )
{
pxDHCPMessage->usFlags = dhcpBROADCAST;
}
else
{
pxDHCPMessage->usFlags = 0;
}
memcpy( ( void * ) &( pxDHCPMessage->ucClientHardwareAddress[ 0 ] ), ( void * ) pxMACAddress, sizeof( xMACAddress_t ) );
/* Copy in the const part of the options options. */
memcpy( ( void * ) &( pucUDPPayloadBuffer[ dhcpFIRST_OPTION_BYTE_OFFSET ] ), ( void * ) pucOptionsArray, xOptionsArraySize );
/* Map in the client identifier. */
memcpy( ( void * ) &( pucUDPPayloadBuffer[ dhcpFIRST_OPTION_BYTE_OFFSET + dhcpCLIENT_IDENTIFIER_OFFSET ] ), ( void * ) pxMACAddress, sizeof( xMACAddress_t ) );
/* Set the addressing. */
pxAddress->sin_addr = ipBROADCAST_IP_ADDRESS;
pxAddress->sin_port = ( uint16_t ) dhcpSERVER_PORT;
return pucUDPPayloadBuffer;
}
/*-----------------------------------------------------------*/
static void prvSendDHCPRequest( xMACAddress_t *pxMACAddress )
{
uint8_t *pucUDPPayloadBuffer;
struct freertos_sockaddr xAddress;
static const uint8_t ucDHCPRequestOptions[] =
{
/* Do not change the ordering without also changing
dhcpCLIENT_IDENTIFIER_OFFSET, dhcpREQUESTED_IP_ADDRESS_OFFSET and
dhcpDHCP_SERVER_IP_ADDRESS_OFFSET. */
dhcpMESSAGE_TYPE_OPTION_CODE, 1, dhcpMESSAGE_TYPE_REQUEST, /* Message type option. */
dhcpCLIENT_IDENTIFIER_OPTION_CODE, 6, 0, 0, 0, 0, 0, 0, /* Client identifier. */
dhcpREQUEST_IP_ADDRESS_OPTION_CODE, 4, 0, 0, 0, 0, /* The IP address being requested. */
dhcpSERVER_IP_ADDRESS_OPTION_CODE, 4, 0, 0, 0, 0, /* The IP address of the DHCP server. */
dhcpOPTION_END_BYTE
};
pucUDPPayloadBuffer = prvCreatePartDHCPMessage( &xAddress, pxMACAddress, dhcpREQUEST_OPCODE, ucDHCPRequestOptions, sizeof( ucDHCPRequestOptions ) );
/* Copy in the IP address being requested. */
memcpy( ( void * ) &( pucUDPPayloadBuffer[ dhcpFIRST_OPTION_BYTE_OFFSET + dhcpREQUESTED_IP_ADDRESS_OFFSET ] ), ( void * ) &ulOfferedIPAddress, sizeof( ulOfferedIPAddress ) );
/* Copy in the address of the DHCP server being used. */
memcpy( ( void * ) &( pucUDPPayloadBuffer[ dhcpFIRST_OPTION_BYTE_OFFSET + dhcpDHCP_SERVER_IP_ADDRESS_OFFSET ] ), ( void * ) &ulDHCPServerAddress, sizeof( ulDHCPServerAddress ) );
iptraceSENDING_DHCP_REQUEST();
if( FreeRTOS_sendto( xDHCPSocket, pucUDPPayloadBuffer, ( sizeof( xDHCPMessage_t ) + sizeof( ucDHCPRequestOptions ) ), FREERTOS_ZERO_COPY, &xAddress, sizeof( xAddress ) ) == 0 )
{
/* The packet was not successfully queued for sending and must be
returned to the stack. */
FreeRTOS_ReleaseUDPPayloadBuffer( pucUDPPayloadBuffer );
}
}
/*-----------------------------------------------------------*/
static void prvSendDHCPDiscover( xMACAddress_t *pxMACAddress )
{
uint8_t *pucUDPPayloadBuffer;
struct freertos_sockaddr xAddress;
static const uint8_t ucDHCPDiscoverOptions[] =
{
/* Do not change the ordering without also changing dhcpCLIENT_IDENTIFIER_OFFSET. */
dhcpMESSAGE_TYPE_OPTION_CODE, 1, dhcpMESSAGE_TYPE_DISCOVER, /* Message type option. */
dhcpCLIENT_IDENTIFIER_OPTION_CODE, 6, 0, 0, 0, 0, 0, 0, /* Client identifier. */
dhcpPARAMETER_REQUEST_OPTION_CODE, 3, dhcpSUBNET_MASK_OPTION_CODE, dhcpGATEWAY_OPTION_CODE, hdcpDNS_SERVER_OPTIONS_CODE, /* Parameter request option. */
dhcpOPTION_END_BYTE
};
pucUDPPayloadBuffer = prvCreatePartDHCPMessage( &xAddress, pxMACAddress, dhcpREQUEST_OPCODE, ucDHCPDiscoverOptions, sizeof( ucDHCPDiscoverOptions ) );
iptraceSENDING_DHCP_DISCOVER();
if( FreeRTOS_sendto( xDHCPSocket, pucUDPPayloadBuffer, ( sizeof( xDHCPMessage_t ) + sizeof( ucDHCPDiscoverOptions ) ), FREERTOS_ZERO_COPY, &xAddress, sizeof( xAddress ) ) == 0 )
{
/* The packet was not successfully queued for sending and must be
returned to the stack. */
FreeRTOS_ReleaseUDPPayloadBuffer( pucUDPPayloadBuffer );
}
}
/*-----------------------------------------------------------*/
#endif /* ipconfigUSE_DHCP != 0 */