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FreeRTOS-RISCV/FreeRTOSv10.2.1/FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/FreeRTOS_DHCP.c

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/*
* FreeRTOS+TCP V2.0.11
* 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://aws.amazon.com/freertos
* http://www.FreeRTOS.org
*/
/* 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_TCP_IP.h"
#include "FreeRTOS_DHCP.h"
#include "FreeRTOS_ARP.h"
#include "NetworkInterface.h"
#include "NetworkBufferManagement.h"
/* Exclude the entire file if DHCP is not enabled. */
#if( ipconfigUSE_DHCP != 0 )
#if ( ipconfigUSE_DHCP != 0 ) && ( ipconfigNETWORK_MTU < 586u )
/* 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
#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 */
#ifndef dhcpINITIAL_DHCP_TX_PERIOD
#define dhcpINITIAL_TIMER_PERIOD ( pdMS_TO_TICKS( 250 ) )
#define dhcpINITIAL_DHCP_TX_PERIOD ( pdMS_TO_TICKS( 5000 ) )
#endif
/* Codes of interest found in the DHCP options field. */
#define dhcpZERO_PAD_OPTION_CODE ( 0u )
#define dhcpSUBNET_MASK_OPTION_CODE ( 1u )
#define dhcpGATEWAY_OPTION_CODE ( 3u )
#define dhcpDNS_SERVER_OPTIONS_CODE ( 6u )
#define dhcpDNS_HOSTNAME_OPTIONS_CODE ( 12u )
#define dhcpREQUEST_IP_ADDRESS_OPTION_CODE ( 50u )
#define dhcpLEASE_TIME_OPTION_CODE ( 51u )
#define dhcpMESSAGE_TYPE_OPTION_CODE ( 53u )
#define dhcpSERVER_IP_ADDRESS_OPTION_CODE ( 54u )
#define dhcpPARAMETER_REQUEST_OPTION_CODE ( 55u )
#define dhcpCLIENT_IDENTIFIER_OPTION_CODE ( 61u )
/* 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. */
/* 48 hours in ticks. Can not use pdMS_TO_TICKS() as integer overflow can occur. */
#define dhcpDEFAULT_LEASE_TIME ( ( 48UL * 60UL * 60UL ) * configTICK_RATE_HZ )
/* Don't allow the lease time to be too short. */
#define dhcpMINIMUM_LEASE_TIME ( pdMS_TO_TICKS( 60000UL ) ) /* 60 seconds in ticks. */
/* Marks the end of the variable length options field in the DHCP packet. */
#define dhcpOPTION_END_BYTE 0xffu
/* 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 == pdFREERTOS_LITTLE_ENDIAN )
#define dhcpCLIENT_PORT 0x4400u
#define dhcpSERVER_PORT 0x4300u
#define dhcpCOOKIE 0x63538263ul
#define dhcpBROADCAST 0x0080u
#else
#define dhcpCLIENT_PORT 0x0044u
#define dhcpSERVER_PORT 0x0043u
#define dhcpCOOKIE 0x63825363ul
#define dhcpBROADCAST 0x8000u
#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 DHCPMessage_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. */
#if( ipconfigDHCP_FALL_BACK_AUTO_IP != 0 )
eGetLinkLayerAddress, /* When DHCP didn't respond, try to obtain a LinkLayer address 168.254.x.x. */
#endif
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;
/* Hold information in between steps in the DHCP state machine. */
struct xDHCP_DATA
{
uint32_t ulTransactionId;
uint32_t ulOfferedIPAddress;
uint32_t ulDHCPServerAddress;
uint32_t ulLeaseTime;
/* Hold information on the current timer state. */
TickType_t xDHCPTxTime;
TickType_t xDHCPTxPeriod;
/* Try both without and with the broadcast flag */
BaseType_t xUseBroadcast;
/* Maintains the DHCP state machine state. */
eDHCPState_t eDHCPState;
/* The UDP socket used for all incoming and outgoing DHCP traffic. */
Socket_t xDHCPSocket;
};
typedef struct xDHCP_DATA DHCPData_t;
#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 void 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 void 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 );
/*
* 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
/*-----------------------------------------------------------*/
/* The next DHCP transaction Id to be used. */
static DHCPData_t xDHCPData;
/*-----------------------------------------------------------*/
BaseType_t xIsDHCPSocket( Socket_t xSocket )
{
BaseType_t xReturn;
if( xDHCPData.xDHCPSocket == xSocket )
{
xReturn = pdTRUE;
}
else
{
xReturn = pdFALSE;
}
return xReturn;
}
/*-----------------------------------------------------------*/
void vDHCPProcess( BaseType_t xReset )
{
BaseType_t xGivingUp = pdFALSE;
#if( ipconfigUSE_DHCP_HOOK != 0 )
eDHCPCallbackAnswer_t eAnswer;
#endif /* ipconfigUSE_DHCP_HOOK */
/* Is DHCP starting over? */
if( xReset != pdFALSE )
{
xDHCPData.eDHCPState = eWaitingSendFirstDiscover;
}
switch( xDHCPData.eDHCPState )
{
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 */
{
/* Initial state. Create the DHCP socket, timer, etc. if they
have not already been created. */
prvInitialiseDHCP();
/* See if prvInitialiseDHCP() has creates a socket. */
if( xDHCPData.xDHCPSocket == NULL )
{
xGivingUp = pdTRUE;
break;
}
*ipLOCAL_IP_ADDRESS_POINTER = 0UL;
/* Send the first discover request. */
if( xDHCPData.xDHCPSocket != NULL )
{
xDHCPData.xDHCPTxTime = xTaskGetTickCount();
prvSendDHCPDiscover( );
xDHCPData.eDHCPState = eWaitingOffer;
}
}
#if( ipconfigUSE_DHCP_HOOK != 0 )
else
{
if( eAnswer == eDHCPUseDefaults )
{
memcpy( &xNetworkAddressing, &xDefaultAddressing, sizeof( xNetworkAddressing ) );
}
/* The user indicates that the DHCP process does not continue. */
xGivingUp = pdTRUE;
}
#endif /* ipconfigUSE_DHCP_HOOK */
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, xDHCPData.ulOfferedIPAddress );
if( eAnswer == eDHCPContinue )
#endif /* ipconfigUSE_DHCP_HOOK */
{
/* An offer has been made, the user wants to continue,
generate the request. */
xDHCPData.xDHCPTxTime = xTaskGetTickCount();
xDHCPData.xDHCPTxPeriod = dhcpINITIAL_DHCP_TX_PERIOD;
prvSendDHCPRequest( );
xDHCPData.eDHCPState = eWaitingAcknowledge;
break;
}
#if( ipconfigUSE_DHCP_HOOK != 0 )
if( eAnswer == eDHCPUseDefaults )
{
memcpy( &xNetworkAddressing, &xDefaultAddressing, sizeof( xNetworkAddressing ) );
}
/* The user indicates that the DHCP process does not continue. */
xGivingUp = pdTRUE;
#endif /* ipconfigUSE_DHCP_HOOK */
}
else if( ( xTaskGetTickCount() - xDHCPData.xDHCPTxTime ) > xDHCPData.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. */
xDHCPData.xDHCPTxPeriod <<= 1;
if( xDHCPData.xDHCPTxPeriod <= ipconfigMAXIMUM_DISCOVER_TX_PERIOD )
{
xDHCPData.ulTransactionId = ipconfigRAND32( );
if( 0 != xDHCPData.ulTransactionId )
{
xDHCPData.xDHCPTxTime = xTaskGetTickCount( );
xDHCPData.xUseBroadcast = !xDHCPData.xUseBroadcast;
prvSendDHCPDiscover( );
FreeRTOS_debug_printf( ( "vDHCPProcess: timeout %lu ticks\n", xDHCPData.xDHCPTxPeriod ) );
}
else
{
FreeRTOS_debug_printf( ( "vDHCPProcess: failed to generate a random Transaction ID\n" ) );
}
}
else
{
FreeRTOS_debug_printf( ( "vDHCPProcess: giving up %lu > %lu ticks\n", xDHCPData.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. */
xDHCPData.eDHCPState = eGetLinkLayerAddress;
}
#else
{
xGivingUp = pdTRUE;
}
#endif /* ipconfigDHCP_FALL_BACK_AUTO_IP */
}
}
break;
case eWaitingAcknowledge :
/* Look for acks coming in. */
if( prvProcessDHCPReplies( dhcpMESSAGE_TYPE_ACK ) == pdPASS )
{
FreeRTOS_debug_printf( ( "vDHCPProcess: acked %lxip\n", FreeRTOS_ntohl( xDHCPData.ulOfferedIPAddress ) ) );
/* DHCP completed. The IP address can now be used, and the
timer set to the lease timeout time. */
*ipLOCAL_IP_ADDRESS_POINTER = xDHCPData.ulOfferedIPAddress;
/* Setting the 'local' broadcast address, something like
'192.168.1.255'. */
xNetworkAddressing.ulBroadcastAddress = ( xDHCPData.ulOfferedIPAddress & xNetworkAddressing.ulNetMask ) | ~xNetworkAddressing.ulNetMask;
xDHCPData.eDHCPState = eLeasedAddress;
iptraceDHCP_SUCCEDEED( xDHCPData.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. */
vSocketClose( xDHCPData.xDHCPSocket );
xDHCPData.xDHCPSocket = NULL;
if( xDHCPData.ulLeaseTime == 0UL )
{
xDHCPData.ulLeaseTime = dhcpDEFAULT_LEASE_TIME;
}
else if( xDHCPData.ulLeaseTime < dhcpMINIMUM_LEASE_TIME )
{
xDHCPData.ulLeaseTime = dhcpMINIMUM_LEASE_TIME;
}
else
{
/* The lease time is already valid. */
}
/* Check for clashes. */
vARPSendGratuitous();
vIPReloadDHCPTimer( xDHCPData.ulLeaseTime );
}
else
{
/* Is it time to send another Discover? */
if( ( xTaskGetTickCount() - xDHCPData.xDHCPTxTime ) > xDHCPData.xDHCPTxPeriod )
{
/* Increase the time period, and if it has not got to the
point of giving up - send another request. */
xDHCPData.xDHCPTxPeriod <<= 1;
if( xDHCPData.xDHCPTxPeriod <= ipconfigMAXIMUM_DISCOVER_TX_PERIOD )
{
xDHCPData.xDHCPTxTime = xTaskGetTickCount();
prvSendDHCPRequest( );
}
else
{
/* Give up, start again. */
xDHCPData.eDHCPState = eWaitingSendFirstDiscover;
}
}
}
break;
#if( ipconfigDHCP_FALL_BACK_AUTO_IP != 0 )
case eGetLinkLayerAddress:
if( ( xTaskGetTickCount() - xDHCPData.xDHCPTxTime ) > xDHCPData.xDHCPTxPeriod )
{
if( xARPHadIPClash == pdFALSE )
{
/* ARP OK. proceed. */
iptraceDHCP_SUCCEDEED( xDHCPData.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( );
xDHCPData.eDHCPState = eNotUsingLeasedAddress;
}
else
{
/* ARP clashed - try another IP address. */
prvPrepareLinkLayerIPLookUp();
/* Setting an IP address manually so set to not using leased
address mode. */
xDHCPData.eDHCPState = eGetLinkLayerAddress;
}
}
break;
#endif /* ipconfigDHCP_FALL_BACK_AUTO_IP */
case eLeasedAddress :
/* Resend the request at the appropriate time to renew the lease. */
prvCreateDHCPSocket();
if( xDHCPData.xDHCPSocket != NULL )
{
xDHCPData.xDHCPTxTime = xTaskGetTickCount();
xDHCPData.xDHCPTxPeriod = dhcpINITIAL_DHCP_TX_PERIOD;
prvSendDHCPRequest( );
xDHCPData.eDHCPState = eWaitingAcknowledge;
/* From now on, we should be called more often */
vIPReloadDHCPTimer( dhcpINITIAL_TIMER_PERIOD );
}
break;
case eNotUsingLeasedAddress:
vIPSetDHCPTimerEnableState( pdFALSE );
break;
default:
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 canceled 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();
xDHCPData.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( );
/* Test if socket was indeed created. */
if( xDHCPData.xDHCPSocket != NULL )
{
/* Close socket to ensure packets don't queue on it. */
vSocketClose( xDHCPData.xDHCPSocket );
xDHCPData.xDHCPSocket = NULL;
}
}
}
/*-----------------------------------------------------------*/
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( xDHCPData.xDHCPSocket == NULL )
{
xDHCPData.xDHCPSocket = FreeRTOS_socket( FREERTOS_AF_INET, FREERTOS_SOCK_DGRAM, FREERTOS_IPPROTO_UDP );
if( xDHCPData.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( xDHCPData.xDHCPSocket, 0, FREERTOS_SO_RCVTIMEO, ( void * ) &xTimeoutTime, sizeof( TickType_t ) );
FreeRTOS_setsockopt( xDHCPData.xDHCPSocket, 0, FREERTOS_SO_SNDTIMEO, ( void * ) &xTimeoutTime, sizeof( TickType_t ) );
/* Bind to the standard DHCP client port. */
xAddress.sin_port = ( uint16_t ) dhcpCLIENT_PORT;
xReturn = vSocketBind( xDHCPData.xDHCPSocket, &xAddress, sizeof( xAddress ), pdFALSE );
if( xReturn != 0 )
{
/* Binding failed, close the socket again. */
vSocketClose( xDHCPData.xDHCPSocket );
xDHCPData.xDHCPSocket = NULL;
}
}
else
{
/* Change to NULL for easier testing. */
xDHCPData.xDHCPSocket = NULL;
}
}
}
/*-----------------------------------------------------------*/
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. */
xDHCPData.ulTransactionId = ipconfigRAND32();
/* Check for random number generator API failure. */
if( 0 != xDHCPData.ulTransactionId )
{
xDHCPData.xUseBroadcast = 0;
xDHCPData.ulOfferedIPAddress = 0UL;
xDHCPData.ulDHCPServerAddress = 0UL;
xDHCPData.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 );
}
}
/*-----------------------------------------------------------*/
static BaseType_t prvProcessDHCPReplies( BaseType_t xExpectedMessageType )
{
uint8_t *pucUDPPayload, *pucLastByte;
struct freertos_sockaddr xClient;
uint32_t xClientLength = sizeof( xClient );
int32_t lBytes;
DHCPMessage_t *pxDHCPMessage;
uint8_t *pucByte, ucOptionCode, ucLength;
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. */
lBytes = FreeRTOS_recvfrom( xDHCPData.xDHCPSocket, ( void * ) &pucUDPPayload, 0ul, FREERTOS_ZERO_COPY, &xClient, &xClientLength );
if( lBytes > 0 )
{
/* Map a DHCP structure onto the received data. */
pxDHCPMessage = ( DHCPMessage_t * ) ( pucUDPPayload );
/* Sanity check. */
if( ( lBytes >= sizeof( DHCPMessage_t ) ) &&
( pxDHCPMessage->ulDHCPCookie == ( uint32_t ) dhcpCOOKIE ) &&
( pxDHCPMessage->ucOpcode == ( uint8_t ) dhcpREPLY_OPCODE ) &&
( pxDHCPMessage->ulTransactionID == FreeRTOS_htonl( xDHCPData.ulTransactionId ) ) )
{
if( memcmp( ( void * ) &( pxDHCPMessage->ucClientHardwareAddress ),
( void * ) ipLOCAL_MAC_ADDRESS,
sizeof( MACAddress_t ) ) == 0 )
{
/* 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 = &( pxDHCPMessage->ucFirstOptionByte );
pucLastByte = &( pucUDPPayload[ lBytes - dhcpMAX_OPTION_LENGTH_OF_INTEREST ] );
while( pucByte < pucLastByte )
{
ucOptionCode = pucByte[ 0 ];
if( ucOptionCode == dhcpOPTION_END_BYTE )
{
/* Ready, the last byte has been seen. */
break;
}
if( ucOptionCode == dhcpZERO_PAD_OPTION_CODE )
{
/* The value zero is used as a pad byte,
it is not followed by a length byte. */
pucByte += 1;
continue;
}
/* Stop if the response is malformed. */
if( pucByte < pucLastByte - 1 )
{
ucLength = pucByte[ 1 ];
pucByte += 2;
if( pucByte >= pucLastByte - ucLength )
{
break;
}
}
else
{
break;
}
/* In most cases, a 4-byte network-endian parameter follows,
just get it once here and use later. */
if( ucLength >= sizeof( ulParameter ) )
{
memcpy( ( void * ) &( ulParameter ),
( void * ) pucByte,
( size_t ) sizeof( ulParameter ) );
}
else
{
ulParameter = 0;
}
/* Option-specific handling. */
switch( ucOptionCode )
{
case dhcpMESSAGE_TYPE_OPTION_CODE :
if( *pucByte == ( uint8_t ) xExpectedMessageType )
{
/* The message type is the message type the
state machine is expecting. */
ulProcessed++;
}
else if( *pucByte == ( uint8_t ) dhcpMESSAGE_TYPE_NACK )
{
if( xExpectedMessageType == ( BaseType_t ) dhcpMESSAGE_TYPE_ACK )
{
/* Start again. */
xDHCPData.eDHCPState = eWaitingSendFirstDiscover;
}
}
else
{
/* Don't process other message types. */
}
break;
case dhcpSUBNET_MASK_OPTION_CODE :
if( ucLength == sizeof( uint32_t ) )
{
xNetworkAddressing.ulNetMask = ulParameter;
}
break;
case dhcpGATEWAY_OPTION_CODE :
if( ucLength == sizeof( uint32_t ) )
{
/* ulProcessed is not incremented in this case
because the gateway is not essential. */
xNetworkAddressing.ulGatewayAddress = ulParameter;
}
break;
case dhcpDNS_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. */
xNetworkAddressing.ulDNSServerAddress = ulParameter;
break;
case dhcpSERVER_IP_ADDRESS_OPTION_CODE :
if( ucLength == sizeof( uint32_t ) )
{
if( xExpectedMessageType == ( BaseType_t ) dhcpMESSAGE_TYPE_OFFER )
{
/* Offers state the replying server. */
ulProcessed++;
xDHCPData.ulDHCPServerAddress = ulParameter;
}
else
{
/* The ack must come from the expected server. */
if( xDHCPData.ulDHCPServerAddress == ulParameter )
{
ulProcessed++;
}
}
}
break;
case dhcpLEASE_TIME_OPTION_CODE :
if( ucLength == sizeof( xDHCPData.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. */
xDHCPData.ulLeaseTime = FreeRTOS_ntohl( ulParameter );
/* Divide the lease time by two to ensure a
renew request is sent before the lease actually
expires. */
xDHCPData.ulLeaseTime >>= 1UL;
/* Multiply with configTICK_RATE_HZ to get clock
ticks. */
xDHCPData.ulLeaseTime = configTICK_RATE_HZ * xDHCPData.ulLeaseTime;
}
break;
default :
/* Not interested in this field. */
break;
}
/* Jump over the data to find the next option code. */
if( ucLength == 0u )
{
break;
}
else
{
pucByte += ucLength;
}
}
/* Were all the mandatory options received? */
if( ulProcessed >= ulMandatoryOptions )
{
/* HT:endian: used to be network order */
xDHCPData.ulOfferedIPAddress = pxDHCPMessage->ulYourIPAddress_yiaddr;
FreeRTOS_printf( ( "vDHCPProcess: offer %lxip\n", FreeRTOS_ntohl( xDHCPData.ulOfferedIPAddress ) ) );
xReturn = pdPASS;
}
}
}
FreeRTOS_ReleaseUDPPayloadBuffer( ( void * ) pucUDPPayload );
}
return xReturn;
}
/*-----------------------------------------------------------*/
static uint8_t *prvCreatePartDHCPMessage( struct freertos_sockaddr *pxAddress, BaseType_t xOpcode, const uint8_t * const pucOptionsArray, size_t *pxOptionsArraySize )
{
DHCPMessage_t *pxDHCPMessage;
size_t xRequiredBufferSize = sizeof( DHCPMessage_t ) + *pxOptionsArraySize;
uint8_t *pucUDPPayloadBuffer;
#if( ipconfigDHCP_REGISTER_HOSTNAME == 1 )
const char *pucHostName = pcApplicationHostnameHook ();
size_t xNameLength = strlen( pucHostName );
uint8_t *pucPtr;
xRequiredBufferSize += ( 2 + xNameLength );
#endif
/* Get a buffer. This uses a maximum delay, but the delay will be capped
to ipconfigUDP_MAX_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 = ( DHCPMessage_t * ) pucUDPPayloadBuffer;
/* Most fields need to be zero. */
memset( ( void * ) pxDHCPMessage, 0x00, sizeof( DHCPMessage_t ) );
/* Create the message. */
pxDHCPMessage->ucOpcode = ( uint8_t ) xOpcode;
pxDHCPMessage->ucAddressType = ( uint8_t ) dhcpADDRESS_TYPE_ETHERNET;
pxDHCPMessage->ucAddressLength = ( uint8_t ) dhcpETHERNET_ADDRESS_LENGTH;
pxDHCPMessage->ulTransactionID = FreeRTOS_htonl( xDHCPData.ulTransactionId );
pxDHCPMessage->ulDHCPCookie = ( uint32_t ) dhcpCOOKIE;
if( xDHCPData.xUseBroadcast != pdFALSE )
{
pxDHCPMessage->usFlags = ( uint16_t ) dhcpBROADCAST;
}
else
{
pxDHCPMessage->usFlags = 0u;
}
memcpy( ( void * ) &( pxDHCPMessage->ucClientHardwareAddress[ 0 ] ), ( void * ) ipLOCAL_MAC_ADDRESS, sizeof( MACAddress_t ) );
/* Copy in the const part of the options options. */
memcpy( ( void * ) &( pucUDPPayloadBuffer[ dhcpFIRST_OPTION_BYTE_OFFSET ] ), ( void * ) pucOptionsArray, *pxOptionsArraySize );
#if( ipconfigDHCP_REGISTER_HOSTNAME == 1 )
{
/* With this option, the hostname can be registered as well which makes
it easier to lookup a device in a router's list of DHCP clients. */
/* Point to where the OPTION_END was stored to add data. */
pucPtr = &( pucUDPPayloadBuffer[ dhcpFIRST_OPTION_BYTE_OFFSET + ( *pxOptionsArraySize - 1 ) ] );
pucPtr[ 0 ] = dhcpDNS_HOSTNAME_OPTIONS_CODE;
pucPtr[ 1 ] = ( uint8_t ) xNameLength;
memcpy( ( void *) ( pucPtr + 2 ), pucHostName, xNameLength );
pucPtr[ 2 + xNameLength ] = dhcpOPTION_END_BYTE;
*pxOptionsArraySize += ( 2 + xNameLength );
}
#endif
/* Map in the client identifier. */
memcpy( ( void * ) &( pucUDPPayloadBuffer[ dhcpFIRST_OPTION_BYTE_OFFSET + dhcpCLIENT_IDENTIFIER_OFFSET ] ),
( void * ) ipLOCAL_MAC_ADDRESS, sizeof( MACAddress_t ) );
/* Set the addressing. */
pxAddress->sin_addr = ipBROADCAST_IP_ADDRESS;
pxAddress->sin_port = ( uint16_t ) dhcpSERVER_PORT;
return pucUDPPayloadBuffer;
}
/*-----------------------------------------------------------*/
static void prvSendDHCPRequest( void )
{
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
};
size_t xOptionsLength = sizeof( ucDHCPRequestOptions );
pucUDPPayloadBuffer = prvCreatePartDHCPMessage( &xAddress, dhcpREQUEST_OPCODE, ucDHCPRequestOptions, &xOptionsLength );
/* Copy in the IP address being requested. */
memcpy( ( void * ) &( pucUDPPayloadBuffer[ dhcpFIRST_OPTION_BYTE_OFFSET + dhcpREQUESTED_IP_ADDRESS_OFFSET ] ),
( void * ) &( xDHCPData.ulOfferedIPAddress ), sizeof( xDHCPData.ulOfferedIPAddress ) );
/* Copy in the address of the DHCP server being used. */
memcpy( ( void * ) &( pucUDPPayloadBuffer[ dhcpFIRST_OPTION_BYTE_OFFSET + dhcpDHCP_SERVER_IP_ADDRESS_OFFSET ] ),
( void * ) &( xDHCPData.ulDHCPServerAddress ), sizeof( xDHCPData.ulDHCPServerAddress ) );
FreeRTOS_debug_printf( ( "vDHCPProcess: reply %lxip\n", FreeRTOS_ntohl( xDHCPData.ulOfferedIPAddress ) ) );
iptraceSENDING_DHCP_REQUEST();
if( FreeRTOS_sendto( xDHCPData.xDHCPSocket, pucUDPPayloadBuffer, ( sizeof( DHCPMessage_t ) + xOptionsLength ), 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( void )
{
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, dhcpDNS_SERVER_OPTIONS_CODE, /* Parameter request option. */
dhcpOPTION_END_BYTE
};
size_t xOptionsLength = sizeof( ucDHCPDiscoverOptions );
pucUDPPayloadBuffer = prvCreatePartDHCPMessage( &xAddress, dhcpREQUEST_OPCODE, ucDHCPDiscoverOptions, &xOptionsLength );
FreeRTOS_debug_printf( ( "vDHCPProcess: discover\n" ) );
iptraceSENDING_DHCP_DISCOVER();
if( FreeRTOS_sendto( xDHCPData.xDHCPSocket, pucUDPPayloadBuffer, ( sizeof( DHCPMessage_t ) + xOptionsLength ), 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 );
}
}
/*-----------------------------------------------------------*/
#if( ipconfigDHCP_FALL_BACK_AUTO_IP != 0 )
static void prvPrepareLinkLayerIPLookUp( void )
{
uint8_t ucLinkLayerIPAddress[ 2 ];
/* After DHCP has failed to answer, prepare everything to start
trying-out LinkLayer IP-addresses, using the random method. */
xDHCPData.xDHCPTxTime = xTaskGetTickCount();
ucLinkLayerIPAddress[ 0 ] = ( uint8_t )1 + ( uint8_t )( ipconfigRAND32() % 0xFDu ); /* get value 1..254 for IP-address 3rd byte of IP address to try. */
ucLinkLayerIPAddress[ 1 ] = ( uint8_t )1 + ( uint8_t )( ipconfigRAND32() % 0xFDu ); /* get value 1..254 for IP-address 4th byte of IP address to try. */
xNetworkAddressing.ulGatewayAddress = FreeRTOS_htonl( 0xA9FE0203 );
/* prepare xDHCPData with data to test. */
xDHCPData.ulOfferedIPAddress =
FreeRTOS_inet_addr_quick( LINK_LAYER_ADDRESS_0, LINK_LAYER_ADDRESS_1, ucLinkLayerIPAddress[ 0 ], ucLinkLayerIPAddress[ 1 ] );
xDHCPData.ulLeaseTime = dhcpDEFAULT_LEASE_TIME; /* don't care about lease time. just put anything. */
xNetworkAddressing.ulNetMask =
FreeRTOS_inet_addr_quick( LINK_LAYER_NETMASK_0, LINK_LAYER_NETMASK_1, LINK_LAYER_NETMASK_2, LINK_LAYER_NETMASK_3 );
/* DHCP completed. The IP address can now be used, and the
timer set to the lease timeout time. */
*ipLOCAL_IP_ADDRESS_POINTER = xDHCPData.ulOfferedIPAddress;
/* Setting the 'local' broadcast address, something like 192.168.1.255' */
xNetworkAddressing.ulBroadcastAddress = ( xDHCPData.ulOfferedIPAddress & xNetworkAddressing.ulNetMask ) | ~xNetworkAddressing.ulNetMask;
/* Close socket to ensure packets don't queue on it. not needed anymore as DHCP failed. but still need timer for ARP testing. */
vSocketClose( xDHCPData.xDHCPSocket );
xDHCPData.xDHCPSocket = NULL;
xDHCPData.xDHCPTxPeriod = pdMS_TO_TICKS( 3000ul + ( ipconfigRAND32() & 0x3fful ) ); /* do ARP test every (3 + 0-1024mS) seconds. */
xARPHadIPClash = pdFALSE; /* reset flag that shows if have ARP clash. */
vARPSendGratuitous();
}
#endif /* ipconfigDHCP_FALL_BACK_AUTO_IP */
/*-----------------------------------------------------------*/
#endif /* ipconfigUSE_DHCP != 0 */
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