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FreeRTOS_DHCP.c
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FreeRTOS_DHCP.c
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/*
* FreeRTOS+TCP V2.3.3
* Copyright (C) 2020 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://aws.amazon.com/freertos
* http://www.FreeRTOS.org
*/
/**
* @file FreeRTOS_DHCP.c
* @brief Implements the Dynamic Host Configuration Protocol for the FreeRTOS+TCP network stack.
*/
/* Standard includes. */
#include <stdint.h>
/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "semphr.h"
/* FreeRTOS+TCP includes. */
#include "FreeRTOS_IP.h"
#include "FreeRTOS_Sockets.h"
#include "FreeRTOS_IP_Private.h"
#include "FreeRTOS_UDP_IP.h"
#include "FreeRTOS_DHCP.h"
#include "FreeRTOS_ARP.h"
/* Exclude the entire file if DHCP is not enabled. */
#if ( ipconfigUSE_DHCP != 0 )
#include "NetworkInterface.h"
#include "NetworkBufferManagement.h"
/**
* @brief Function to cast pointers to DHCPMessage_IPv4_t.
*/
static portINLINE ipDECL_CAST_PTR_FUNC_FOR_TYPE( DHCPMessage_IPv4_t )
{
return ( DHCPMessage_IPv4_t * ) pvArgument;
}
/**
* @brief Function to cast const pointers to DHCPMessage_IPv4_t.
*/
static portINLINE ipDECL_CAST_CONST_PTR_FUNC_FOR_TYPE( DHCPMessage_IPv4_t )
{
return ( const DHCPMessage_IPv4_t * ) pvArgument;
}
/** @brief The UDP socket used for all incoming and outgoing DHCP traffic. */
_static Socket_t xDHCPSocket;
#if ( ipconfigDHCP_FALL_BACK_AUTO_IP != 0 )
/* Define the Link Layer IP address: 169.254.x.x */
#define LINK_LAYER_ADDRESS_0 169
#define LINK_LAYER_ADDRESS_1 254
/* Define the netmask used: 255.255.0.0 */
#define LINK_LAYER_NETMASK_0 255
#define LINK_LAYER_NETMASK_1 255
#define LINK_LAYER_NETMASK_2 0
#define LINK_LAYER_NETMASK_3 0
#endif
/*
* Generate a DHCP discover message and send it on the DHCP socket.
*/
static BaseType_t prvSendDHCPDiscover( void );
/*
* Interpret message received on the DHCP socket.
*/
_static BaseType_t prvProcessDHCPReplies( BaseType_t xExpectedMessageType );
/*
* Generate a DHCP request packet, and send it on the DHCP socket.
*/
static BaseType_t prvSendDHCPRequest( void );
/*
* 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,
BaseType_t xOpcode,
const uint8_t * const pucOptionsArray,
size_t * pxOptionsArraySize );
/*
* Create the DHCP socket, if it has not been created already.
*/
_static void prvCreateDHCPSocket( void );
/*
* Close the DHCP socket.
*/
static void prvCloseDHCPSocket( void );
/*
* After DHCP has failed to answer, prepare everything to start searching
* for (trying-out) LinkLayer IP-addresses, using the random method: Send
* a gratuitous ARP request and wait if another device responds to it.
*/
#if ( ipconfigDHCP_FALL_BACK_AUTO_IP != 0 )
static void prvPrepareLinkLayerIPLookUp( void );
#endif
/*-----------------------------------------------------------*/
/** @brief Hold information in between steps in the DHCP state machine. */
_static DHCPData_t xDHCPData;
/*-----------------------------------------------------------*/
/**
* @brief Check whether a given socket is the DHCP socket or not.
*
* @param[in] xSocket: The socket to be checked.
*
* @return If the socket given as parameter is the DHCP socket - return
* pdTRUE, else pdFALSE.
*/
BaseType_t xIsDHCPSocket( Socket_t xSocket )
{
BaseType_t xReturn;
if( xDHCPSocket == xSocket )
{
xReturn = pdTRUE;
}
else
{
xReturn = pdFALSE;
}
return xReturn;
}
/*-----------------------------------------------------------*/
/**
* @brief The application can indicate a preferred IP address by calling this function.
* before starting up the IP-task by calling FreeRTOS_IPInit().
*
* @param[in] ulIPAddress: The preferred IP-address.
*
* @return The previous value of ulPreferredIPAddress.
*/
uint32_t vDHCPSetPreferredIPAddress( uint32_t ulIPAddress )
{
uint32_t ulPrevious = xDHCPData.ulPreferredIPAddress;
xDHCPData.ulPreferredIPAddress = ulIPAddress;
return ulPrevious;
}
/**
* @brief Returns the current state of a DHCP process.
*
* @return The current state ( eDHCPState_t ) of the DHCP process.
*/
eDHCPState_t eGetDHCPState( void )
{
return EP_DHCPData.eDHCPState;
}
/**
* @brief Process the DHCP state machine based on current state.
*
* @param[in] xReset: Is the DHCP state machine starting over? pdTRUE/pdFALSE.
* @param[in] eExpectedState: The function will only run if the state is expected.
*/
void vDHCPProcess( BaseType_t xReset,
eDHCPState_t eExpectedState )
{
BaseType_t xGivingUp = pdFALSE;
#if ( ipconfigUSE_DHCP_HOOK != 0 )
eDHCPCallbackAnswer_t eAnswer;
#endif /* ipconfigUSE_DHCP_HOOK */
/* Is DHCP starting over? */
if( xReset != pdFALSE )
{
EP_DHCPData.eDHCPState = eInitialWait;
}
if( ( EP_DHCPData.eDHCPState != eExpectedState ) && ( xReset == pdFALSE ) )
{
/* When the DHCP event was generated, the DHCP client was
* in a different state. Therefore, ignore this event. */
FreeRTOS_debug_printf( ( "DHCP wrong state: expect: %d got: %d : ignore\n",
eExpectedState, EP_DHCPData.eDHCPState ) );
}
else
{
switch( EP_DHCPData.eDHCPState )
{
case eInitialWait:
/* Initial state. Create the DHCP socket, timer, etc. if they
* have not already been created. */
prvInitialiseDHCP();
EP_DHCPData.eDHCPState = eWaitingSendFirstDiscover;
break;
case eWaitingSendFirstDiscover:
/* Ask the user if a DHCP discovery is required. */
#if ( ipconfigUSE_DHCP_HOOK != 0 )
eAnswer = xApplicationDHCPHook( eDHCPPhasePreDiscover, xNetworkAddressing.ulDefaultIPAddress );
if( eAnswer == eDHCPContinue )
#endif /* ipconfigUSE_DHCP_HOOK */
{
/* See if prvInitialiseDHCP() has creates a socket. */
if( xDHCPSocket == NULL )
{
xGivingUp = pdTRUE;
}
else
{
*ipLOCAL_IP_ADDRESS_POINTER = 0UL;
/* Send the first discover request. */
EP_DHCPData.xDHCPTxTime = xTaskGetTickCount();
if( prvSendDHCPDiscover() == pdPASS )
{
EP_DHCPData.eDHCPState = eWaitingOffer;
}
else
{
/* Either the creation of a message buffer failed, or sendto().
* Try again in the next cycle. */
FreeRTOS_debug_printf( ( "Send failed during eWaitingSendFirstDiscover\n" ) );
}
}
}
#if ( ipconfigUSE_DHCP_HOOK != 0 )
else
{
if( eAnswer == eDHCPUseDefaults )
{
( void ) memcpy( &( xNetworkAddressing ), &( xDefaultAddressing ), sizeof( xNetworkAddressing ) );
}
/* The user indicates that the DHCP process does not continue. */
xGivingUp = pdTRUE;
}
#endif /* ipconfigUSE_DHCP_HOOK */
break;
case eSendDHCPRequest:
if( prvSendDHCPRequest() == pdPASS )
{
/* Send succeeded, go to state 'eWaitingAcknowledge'. */
EP_DHCPData.xDHCPTxTime = xTaskGetTickCount();
EP_DHCPData.xDHCPTxPeriod = dhcpINITIAL_DHCP_TX_PERIOD;
EP_DHCPData.eDHCPState = eWaitingAcknowledge;
}
else
{
/* Either the creation of a message buffer failed, or sendto().
* Try again in the next cycle. */
FreeRTOS_debug_printf( ( "Send failed during eSendDHCPRequest.\n" ) );
}
break;
case eWaitingOffer:
xGivingUp = pdFALSE;
/* Look for offers coming in. */
if( prvProcessDHCPReplies( dhcpMESSAGE_TYPE_OFFER ) == pdPASS )
{
#if ( ipconfigUSE_DHCP_HOOK != 0 )
/* Ask the user if a DHCP request is required. */
eAnswer = xApplicationDHCPHook( eDHCPPhasePreRequest, EP_DHCPData.ulOfferedIPAddress );
if( eAnswer == eDHCPContinue )
#endif /* ipconfigUSE_DHCP_HOOK */
{
/* An offer has been made, the user wants to continue,
* generate the request. */
if( prvSendDHCPRequest() == pdPASS )
{
EP_DHCPData.xDHCPTxTime = xTaskGetTickCount();
EP_DHCPData.xDHCPTxPeriod = dhcpINITIAL_DHCP_TX_PERIOD;
EP_DHCPData.eDHCPState = eWaitingAcknowledge;
}
else
{
/* Either the creation of a message buffer failed, or sendto().
* Try again in the next cycle. */
FreeRTOS_debug_printf( ( "Send failed during eWaitingOffer/1.\n" ) );
EP_DHCPData.eDHCPState = eSendDHCPRequest;
}
break;
}
#if ( ipconfigUSE_DHCP_HOOK != 0 )
if( eAnswer == eDHCPUseDefaults )
{
( void ) memcpy( &( xNetworkAddressing ), &( xDefaultAddressing ), sizeof( xNetworkAddressing ) );
}
/* The user indicates that the DHCP process does not continue. */
xGivingUp = pdTRUE;
#endif /* ipconfigUSE_DHCP_HOOK */
}
/* Is it time to send another Discover? */
else if( ( xTaskGetTickCount() - EP_DHCPData.xDHCPTxTime ) > EP_DHCPData.xDHCPTxPeriod )
{
/* It is time to send another Discover. Increase the time
* period, and if it has not got to the point of giving up - send
* another discovery. */
EP_DHCPData.xDHCPTxPeriod <<= 1;
if( EP_DHCPData.xDHCPTxPeriod <= ( TickType_t ) ipconfigMAXIMUM_DISCOVER_TX_PERIOD )
{
if( xApplicationGetRandomNumber( &( EP_DHCPData.ulTransactionId ) ) != pdFALSE )
{
EP_DHCPData.xDHCPTxTime = xTaskGetTickCount();
if( EP_DHCPData.xUseBroadcast != pdFALSE )
{
EP_DHCPData.xUseBroadcast = pdFALSE;
}
else
{
EP_DHCPData.xUseBroadcast = pdTRUE;
}
if( prvSendDHCPDiscover() == pdPASS )
{
FreeRTOS_debug_printf( ( "vDHCPProcess: timeout %lu ticks\n", EP_DHCPData.xDHCPTxPeriod ) );
}
else
{
/* Either the creation of a message buffer failed, or sendto().
* Try again in the next cycle. */
FreeRTOS_debug_printf( ( "Send failed during eWaitingOffer/2.\n" ) );
EP_DHCPData.eDHCPState = eInitialWait;
}
}
else
{
FreeRTOS_debug_printf( ( "vDHCPProcess: failed to generate a random Transaction ID\n" ) );
}
}
else
{
FreeRTOS_debug_printf( ( "vDHCPProcess: giving up %lu > %lu ticks\n", EP_DHCPData.xDHCPTxPeriod, ipconfigMAXIMUM_DISCOVER_TX_PERIOD ) );
#if ( ipconfigDHCP_FALL_BACK_AUTO_IP != 0 )
{
/* Only use a fake Ack if the default IP address == 0x00
* and the link local addressing is used. Start searching
* a free LinkLayer IP-address. Next state will be
* 'eGetLinkLayerAddress'. */
prvPrepareLinkLayerIPLookUp();
/* Setting an IP address manually so set to not using
* leased address mode. */
EP_DHCPData.eDHCPState = eGetLinkLayerAddress;
}
#else
{
xGivingUp = pdTRUE;
}
#endif /* ipconfigDHCP_FALL_BACK_AUTO_IP */
}
}
else
{
/* There was no DHCP reply, there was no time-out, just keep on waiting. */
}
break;
case eWaitingAcknowledge:
/* Look for acks coming in. */
if( prvProcessDHCPReplies( dhcpMESSAGE_TYPE_ACK ) == pdPASS )
{
FreeRTOS_debug_printf( ( "vDHCPProcess: acked %lxip\n", FreeRTOS_ntohl( EP_DHCPData.ulOfferedIPAddress ) ) );
/* DHCP completed. The IP address can now be used, and the
* timer set to the lease timeout time. */
*ipLOCAL_IP_ADDRESS_POINTER = EP_DHCPData.ulOfferedIPAddress;
/* Setting the 'local' broadcast address, something like
* '192.168.1.255'. */
EP_IPv4_SETTINGS.ulBroadcastAddress = ( EP_DHCPData.ulOfferedIPAddress & xNetworkAddressing.ulNetMask ) | ~xNetworkAddressing.ulNetMask;
EP_DHCPData.eDHCPState = eLeasedAddress;
iptraceDHCP_SUCCEDEED( EP_DHCPData.ulOfferedIPAddress );
/* DHCP failed, the default configured IP-address will be used
* Now call vIPNetworkUpCalls() to send the network-up event and
* start the ARP timer. */
vIPNetworkUpCalls();
/* Close socket to ensure packets don't queue on it. */
prvCloseDHCPSocket();
if( EP_DHCPData.ulLeaseTime == 0UL )
{
EP_DHCPData.ulLeaseTime = ( uint32_t ) dhcpDEFAULT_LEASE_TIME;
}
else if( EP_DHCPData.ulLeaseTime < dhcpMINIMUM_LEASE_TIME )
{
EP_DHCPData.ulLeaseTime = dhcpMINIMUM_LEASE_TIME;
}
else
{
/* The lease time is already valid. */
}
/* Check for clashes. */
vARPSendGratuitous();
vIPReloadDHCPTimer( EP_DHCPData.ulLeaseTime );
}
else
{
/* Is it time to send another Discover? */
if( ( xTaskGetTickCount() - EP_DHCPData.xDHCPTxTime ) > EP_DHCPData.xDHCPTxPeriod )
{
/* Increase the time period, and if it has not got to the
* point of giving up - send another request. */
EP_DHCPData.xDHCPTxPeriod <<= 1;
if( EP_DHCPData.xDHCPTxPeriod <= ( TickType_t ) ipconfigMAXIMUM_DISCOVER_TX_PERIOD )
{
EP_DHCPData.xDHCPTxTime = xTaskGetTickCount();
if( prvSendDHCPRequest() == pdPASS )
{
/* The message is sent. Stay in state 'eWaitingAcknowledge'. */
}
else
{
/* Either the creation of a message buffer failed, or sendto().
* Try again in the next cycle. */
FreeRTOS_debug_printf( ( "Send failed during eWaitingAcknowledge.\n" ) );
EP_DHCPData.eDHCPState = eSendDHCPRequest;
}
}
else
{
/* Give up, start again. */
EP_DHCPData.eDHCPState = eInitialWait;
}
}
}
break;
#if ( ipconfigDHCP_FALL_BACK_AUTO_IP != 0 )
case eGetLinkLayerAddress:
if( ( xTaskGetTickCount() - EP_DHCPData.xDHCPTxTime ) > EP_DHCPData.xDHCPTxPeriod )
{
if( xARPHadIPClash == pdFALSE )
{
/* ARP OK. proceed. */
iptraceDHCP_SUCCEDEED( EP_DHCPData.ulOfferedIPAddress );
/* Auto-IP succeeded, the default configured IP-address will
* be used. Now call vIPNetworkUpCalls() to send the
* network-up event and start the ARP timer. */
vIPNetworkUpCalls();
EP_DHCPData.eDHCPState = eNotUsingLeasedAddress;
}
else
{
/* ARP clashed - try another IP address. */
prvPrepareLinkLayerIPLookUp();
/* Setting an IP address manually so set to not using leased
* address mode. */
EP_DHCPData.eDHCPState = eGetLinkLayerAddress;
}
}
break;
#endif /* ipconfigDHCP_FALL_BACK_AUTO_IP */
case eLeasedAddress:
if( FreeRTOS_IsNetworkUp() != 0 )
{
/* Resend the request at the appropriate time to renew the lease. */
prvCreateDHCPSocket();
if( xDHCPSocket != NULL )
{
uint32_t ulID;
if( xApplicationGetRandomNumber( &( ulID ) ) != pdFALSE )
{
EP_DHCPData.ulTransactionId = ulID;
}
EP_DHCPData.xDHCPTxTime = xTaskGetTickCount();
EP_DHCPData.xDHCPTxPeriod = dhcpINITIAL_DHCP_TX_PERIOD;
if( prvSendDHCPRequest() == pdPASS )
{
/* The packet was sent successfully, wait for an acknowledgement. */
EP_DHCPData.eDHCPState = eWaitingAcknowledge;
}
else
{
/* The packet was not sent, try sending it later. */
EP_DHCPData.eDHCPState = eSendDHCPRequest;
FreeRTOS_debug_printf( ( "Send failed eLeasedAddress.\n" ) );
}
/* From now on, we should be called more often */
vIPReloadDHCPTimer( dhcpINITIAL_TIMER_PERIOD );
}
}
else
{
/* See PR #53 on github/freertos/freertos */
FreeRTOS_printf( ( "DHCP: lease time finished but network is down\n" ) );
vIPReloadDHCPTimer( pdMS_TO_TICKS( 5000U ) );
}
break;
case eNotUsingLeasedAddress:
vIPSetDHCPTimerEnableState( pdFALSE );
break;
default:
/* Lint: all options are included. */
break;
}
if( xGivingUp != pdFALSE )
{
/* xGivingUp became true either because of a time-out, or because
* xApplicationDHCPHook() returned another value than 'eDHCPContinue',
* meaning that the conversion is cancelled from here. */
/* Revert to static IP address. */
taskENTER_CRITICAL();
{
*ipLOCAL_IP_ADDRESS_POINTER = xNetworkAddressing.ulDefaultIPAddress;
iptraceDHCP_REQUESTS_FAILED_USING_DEFAULT_IP_ADDRESS( xNetworkAddressing.ulDefaultIPAddress );
}
taskEXIT_CRITICAL();
EP_DHCPData.eDHCPState = eNotUsingLeasedAddress;
vIPSetDHCPTimerEnableState( pdFALSE );
/* DHCP failed, the default configured IP-address will be used. Now
* call vIPNetworkUpCalls() to send the network-up event and start the ARP
* timer. */
vIPNetworkUpCalls();
/* Close socket to ensure packets don't queue on it. */
prvCloseDHCPSocket();
}
}
}
/*-----------------------------------------------------------*/
/**
* @brief Close the DHCP socket.
*/
static void prvCloseDHCPSocket( void )
{
if( xDHCPSocket != NULL )
{
/* This modules runs from the IP-task. Use the internal
* function 'vSocketClose()` to close the socket. */
( void ) vSocketClose( xDHCPSocket );
xDHCPSocket = NULL;
}
}
/*-----------------------------------------------------------*/
/**
* @brief Create a DHCP socket with the defined timeouts.
*/
_static void prvCreateDHCPSocket( void )
{
struct freertos_sockaddr xAddress;
BaseType_t xReturn;
TickType_t xTimeoutTime = ( TickType_t ) 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 );
if( xDHCPSocket != FREERTOS_INVALID_SOCKET )
{
/* Ensure the Rx and Tx timeouts are zero as the DHCP executes in the
* context of the IP task. */
( void ) FreeRTOS_setsockopt( xDHCPSocket, 0, FREERTOS_SO_RCVTIMEO, &( xTimeoutTime ), sizeof( TickType_t ) );
( void ) FreeRTOS_setsockopt( xDHCPSocket, 0, FREERTOS_SO_SNDTIMEO, &( xTimeoutTime ), sizeof( TickType_t ) );
/* Bind to the standard DHCP client port. */
xAddress.sin_port = ( uint16_t ) dhcpCLIENT_PORT_IPv4;
xReturn = vSocketBind( xDHCPSocket, &xAddress, sizeof( xAddress ), pdFALSE );
if( xReturn != 0 )
{
/* Binding failed, close the socket again. */
prvCloseDHCPSocket();
}
}
else
{
/* Change to NULL for easier testing. */
xDHCPSocket = NULL;
}
}
}
/*-----------------------------------------------------------*/
/**
* @brief Initialise the DHCP state machine by creating DHCP socket and
* begin the transaction.
*/
static void prvInitialiseDHCP( void )
{
/* Initialise the parameters that will be set by the DHCP process. Per
* https://www.ietf.org/rfc/rfc2131.txt, Transaction ID should be a random
* value chosen by the client. */
/* Check for random number generator API failure. */
if( xApplicationGetRandomNumber( &( EP_DHCPData.ulTransactionId ) ) != pdFALSE )
{
EP_DHCPData.xUseBroadcast = 0;
EP_DHCPData.ulOfferedIPAddress = 0UL;
EP_DHCPData.ulDHCPServerAddress = 0UL;
EP_DHCPData.xDHCPTxPeriod = dhcpINITIAL_DHCP_TX_PERIOD;
/* Create the DHCP socket if it has not already been created. */
prvCreateDHCPSocket();
FreeRTOS_debug_printf( ( "prvInitialiseDHCP: start after %lu ticks\n", dhcpINITIAL_TIMER_PERIOD ) );
vIPReloadDHCPTimer( dhcpINITIAL_TIMER_PERIOD );
}
else
{
/* There was a problem with the randomiser. */
}
}
/*-----------------------------------------------------------*/
/**
* @brief Process the DHCP replies.
*
* @param[in] xExpectedMessageType: The type of the message the DHCP state machine is expecting.
* Messages of different type will be dropped.
*
* @return pdPASS: if DHCP options are received correctly; pdFAIL: Otherwise.
*/
_static BaseType_t prvProcessDHCPReplies( BaseType_t xExpectedMessageType )
{
uint8_t * pucUDPPayload;
int32_t lBytes;
const DHCPMessage_IPv4_t * pxDHCPMessage;
const uint8_t * pucByte;
uint8_t ucOptionCode;
uint32_t ulProcessed, ulParameter;
BaseType_t xReturn = pdFALSE;
const uint32_t ulMandatoryOptions = 2UL; /* DHCP server address, and the correct DHCP message type must be present in the options. */
/* memcpy() helper variables for MISRA Rule 21.15 compliance*/
const void * pvCopySource;
void * pvCopyDest;
/* Passing the address of a pointer (pucUDPPayload) because FREERTOS_ZERO_COPY is used. */
lBytes = FreeRTOS_recvfrom( xDHCPSocket, &pucUDPPayload, 0UL, FREERTOS_ZERO_COPY, NULL, NULL );
if( lBytes > 0 )
{
/* Map a DHCP structure onto the received data. */
pxDHCPMessage = ipCAST_CONST_PTR_TO_CONST_TYPE_PTR( DHCPMessage_IPv4_t, pucUDPPayload );
/* Sanity check. */
if( lBytes < ( int32_t ) sizeof( DHCPMessage_IPv4_t ) )
{
/* Not enough bytes. */
}
else if( ( pxDHCPMessage->ulDHCPCookie != ( uint32_t ) dhcpCOOKIE ) ||
( pxDHCPMessage->ucOpcode != ( uint8_t ) dhcpREPLY_OPCODE ) )
{
/* Invalid cookie or unexpected opcode. */
}
else if( ( pxDHCPMessage->ulTransactionID != FreeRTOS_htonl( EP_DHCPData.ulTransactionId ) ) )
{
/* Transaction ID does not match. */
}
else /* Looks like a valid DHCP response, with the same transaction ID. */
{
if( memcmp( pxDHCPMessage->ucClientHardwareAddress,
ipLOCAL_MAC_ADDRESS,
sizeof( MACAddress_t ) ) != 0 )
{
/* Target MAC address doesn't match. */
}
else
{
size_t uxIndex, uxPayloadDataLength, uxLength;
/* None of the essential options have been processed yet. */
ulProcessed = 0UL;
/* Walk through the options until the dhcpOPTION_END_BYTE byte
* is found, taking care not to walk off the end of the options. */
pucByte = &( pucUDPPayload[ sizeof( DHCPMessage_IPv4_t ) ] );
uxIndex = 0;
uxPayloadDataLength = ( ( size_t ) lBytes ) - sizeof( DHCPMessage_IPv4_t );
while( uxIndex < uxPayloadDataLength )
{
ucOptionCode = pucByte[ uxIndex ];
if( ucOptionCode == ( uint8_t ) dhcpOPTION_END_BYTE )
{
/* Ready, the last byte has been seen. */
/* coverity[break_stmt] : Break statement terminating the loop */
break;
}
if( ucOptionCode == ( uint8_t ) dhcpIPv4_ZERO_PAD_OPTION_CODE )
{
/* The value zero is used as a pad byte,
* it is not followed by a length byte. */
uxIndex = uxIndex + 1U;
continue;
}
/* Stop if the response is malformed. */
if( ( uxIndex + 1U ) < uxPayloadDataLength )
{
/* Fetch the length byte. */
uxLength = ( size_t ) pucByte[ uxIndex + 1U ];
uxIndex = uxIndex + 2U;
if( !( ( ( uxIndex + uxLength ) - 1U ) < uxPayloadDataLength ) )
{
/* There are not as many bytes left as there should be. */
break;
}
}
else
{
/* The length byte is missing. */
break;
}
/* In most cases, a 4-byte network-endian parameter follows,
* just get it once here and use later. */
if( uxLength >= sizeof( ulParameter ) )
{
/*
* Use helper variables for memcpy() to remain
* compliant with MISRA Rule 21.15. These should be
* optimized away.
*/
pvCopySource = &pucByte[ uxIndex ];
pvCopyDest = &ulParameter;
( void ) memcpy( pvCopyDest, pvCopySource, sizeof( ulParameter ) );
/* 'uxIndex' will be increased at the end of this loop. */
}
else
{
ulParameter = 0;
}
/* Confirm uxIndex is still a valid index after adjustments to uxIndex above */
if( !( uxIndex < uxPayloadDataLength ) )
{
break;
}
/* Option-specific handling. */
switch( ucOptionCode )
{
case dhcpIPv4_MESSAGE_TYPE_OPTION_CODE:
if( pucByte[ uxIndex ] == ( uint8_t ) xExpectedMessageType )
{
/* The message type is the message type the
* state machine is expecting. */
ulProcessed++;
}
else
{
if( pucByte[ uxIndex ] == ( uint8_t ) dhcpMESSAGE_TYPE_NACK )
{
if( xExpectedMessageType == ( BaseType_t ) dhcpMESSAGE_TYPE_ACK )
{
/* Start again. */
EP_DHCPData.eDHCPState = eInitialWait;
}
}
/* Stop processing further options. */
uxLength = 0;
}
break;
case dhcpIPv4_SUBNET_MASK_OPTION_CODE:
if( uxLength == sizeof( uint32_t ) )
{
EP_IPv4_SETTINGS.ulNetMask = ulParameter;
}
break;
case dhcpIPv4_GATEWAY_OPTION_CODE:
/* The DHCP server may send more than 1 gateway addresses. */
if( uxLength >= sizeof( uint32_t ) )
{
/* ulProcessed is not incremented in this case
* because the gateway is not essential. */
EP_IPv4_SETTINGS.ulGatewayAddress = ulParameter;
}
break;
case dhcpIPv4_DNS_SERVER_OPTIONS_CODE:
/* The DHCP server may send more than 1 DNS server addresses. */
if( uxLength >= sizeof( uint32_t ) )
{
/* ulProcessed is not incremented in this case
* because the DNS server is not essential. Only the
* first DNS server address is taken. */
EP_IPv4_SETTINGS.ulDNSServerAddress = ulParameter;
}
break;
case dhcpIPv4_SERVER_IP_ADDRESS_OPTION_CODE:
if( uxLength == sizeof( uint32_t ) )
{
if( xExpectedMessageType == ( BaseType_t ) dhcpMESSAGE_TYPE_OFFER )
{
/* Offers state the replying server. */
ulProcessed++;
EP_DHCPData.ulDHCPServerAddress = ulParameter;
}
else
{
/* The ack must come from the expected server. */
if( EP_DHCPData.ulDHCPServerAddress == ulParameter )
{
ulProcessed++;
}
}
}
break;
case dhcpIPv4_LEASE_TIME_OPTION_CODE:
if( uxLength == sizeof( EP_DHCPData.ulLeaseTime ) )
{
/* ulProcessed is not incremented in this case
* because the lease time is not essential. */
/* The DHCP parameter is in seconds, convert
* to host-endian format. */
EP_DHCPData.ulLeaseTime = FreeRTOS_ntohl( ulParameter );
/* Divide the lease time by two to ensure a renew
* request is sent before the lease actually expires. */
EP_DHCPData.ulLeaseTime >>= 1UL;
/* Multiply with configTICK_RATE_HZ to get clock ticks. */
EP_DHCPData.ulLeaseTime = ( uint32_t ) configTICK_RATE_HZ * ( uint32_t ) EP_DHCPData.ulLeaseTime;
}
break;
default:
/* Not interested in this field. */
break;
}
/* Jump over the data to find the next option code. */
if( uxLength == 0U )
{
break;
}
uxIndex = uxIndex + uxLength;
}
/* Were all the mandatory options received? */
if( ulProcessed >= ulMandatoryOptions )
{
/* HT:endian: used to be network order */
EP_DHCPData.ulOfferedIPAddress = pxDHCPMessage->ulYourIPAddress_yiaddr;
FreeRTOS_printf( ( "vDHCPProcess: offer %lxip\n", FreeRTOS_ntohl( EP_DHCPData.ulOfferedIPAddress ) ) );
xReturn = pdPASS;
}
}
}
FreeRTOS_ReleaseUDPPayloadBuffer( pucUDPPayload );
} /* if( lBytes > 0 ) */
return xReturn;
}
/*-----------------------------------------------------------*/
/**
* @brief Create a partial DHCP message by filling in all the 'constant' fields.
*
* @param[out] pxAddress: Address to be filled in.
* @param[out] xOpcode: Opcode to be filled in the packet. Will always be 'dhcpREQUEST_OPCODE'.
* @param[in] pucOptionsArray: The options to be added to the packet.
* @param[in,out] pxOptionsArraySize: Byte count of the options. Its value might change.
*
* @return Ethernet buffer of the partially created DHCP packet.
*/
static uint8_t * prvCreatePartDHCPMessage( struct freertos_sockaddr * pxAddress,
BaseType_t xOpcode,
const uint8_t * const pucOptionsArray,
size_t * pxOptionsArraySize )
{
DHCPMessage_IPv4_t * pxDHCPMessage;
size_t uxRequiredBufferSize = sizeof( DHCPMessage_IPv4_t ) + *pxOptionsArraySize;
const NetworkBufferDescriptor_t * pxNetworkBuffer;
uint8_t * pucUDPPayloadBuffer = NULL;
#if ( ipconfigDHCP_REGISTER_HOSTNAME == 1 )
const char * pucHostName = pcApplicationHostnameHook();
size_t uxNameLength = strlen( pucHostName );
uint8_t * pucPtr;
/* memcpy() helper variables for MISRA Rule 21.15 compliance*/
const void * pvCopySource;
void * pvCopyDest;
/* Two extra bytes for option code and length. */
uxRequiredBufferSize += ( 2U + uxNameLength );
#endif /* if ( ipconfigDHCP_REGISTER_HOSTNAME == 1 ) */
/* Obtain a network buffer with the required amount of storage. It doesn't make much sense
* to use a time-out here, because that would cause the IP-task to wait for itself. */
pxNetworkBuffer = pxGetNetworkBufferWithDescriptor( sizeof( UDPPacket_t ) + uxRequiredBufferSize, 0U );
if( pxNetworkBuffer != NULL )
{
/* Leave space for the UDP header. */
pucUDPPayloadBuffer = &( pxNetworkBuffer->pucEthernetBuffer[ ipUDP_PAYLOAD_OFFSET_IPv4 ] );
pxDHCPMessage = ipCAST_PTR_TO_TYPE_PTR( DHCPMessage_IPv4_t, pucUDPPayloadBuffer );
/* Most fields need to be zero. */
( void ) memset( pxDHCPMessage, 0x00, sizeof( DHCPMessage_IPv4_t ) );