/***********************************************************************Dynamic Host Configuration Protocol (DHCP) Client*Module for Microchip TCP/IP Stack* -Provides automatic IP address, subnet mask, gateway address, * DNS server address, and other configuration parameters on DHCP * enabled networks.* -Reference: RFC 2131, 2132*********************************************************************** FileName:DHCP.c* Dependencies:UDP* Processor:PIC18, PIC24F, PIC24H, dsPIC30F, dsPIC33F, PIC32* Compiler:Microchip C32 v1.05 or higher*Microchip C30 v3.12 or higher*Microchip C18 v3.30 or higher*HI-TECH PICC-18 PRO 9.63PL2 or higher* Company:Microchip Technology, Inc.** Software License Agreement** Copyright (C) 2002-2009 Microchip Technology Inc. All rights* reserved.** Microchip licenses to you the right to use, modify, copy, and* distribute:* (i) the Software when embedded on a Microchip microcontroller or* digital signal controller product ("Device") which is* integrated into Licensee's product; or* (ii) ONLY the Software driver source files ENC28J60.c, ENC28J60.h,*ENCX24J600.c and ENCX24J600.h ported to a non-Microchip device*used in conjunction with a Microchip ethernet controller for*the sole purpose of interfacing with the ethernet controller.** You should refer to the license agreement accompanying this* Software for additional information regarding your rights and* obligations.** THE SOFTWARE AND DOCUMENTATION ARE PROVIDED "AS IS" WITHOUT* WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT* LIMITATION, ANY WARRANTY OF MERCHANTABILITY, FITNESS FOR A* PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT SHALL* MICROCHIP BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR* CONSEQUENTIAL DAMAGES, LOST PROFITS OR LOST DATA, COST OF* PROCUREMENT OF SUBSTITUTE GOODS, TECHNOLOGY OR SERVICES, ANY CLAIMS* BY THIRD PARTIES (INCLUDING BUT NOT LIMITED TO ANY DEFENSE* THEREOF), ANY CLAIMS FOR INDEMNITY OR CONTRIBUTION, OR OTHER* SIMILAR COSTS, WHETHER ASSERTED ON THE BASIS OF CONTRACT, TORT* (INCLUDING NEGLIGENCE), BREACH OF WARRANTY, OR OTHERWISE.*** Author Date Comment*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~* Nilesh Rajbharti 3/21/01 Original (Rev 1.0)* Nilesh Rajbharti 7/10/02 Explicitly initialized tempIPAddress* (Rev 2.11)* Nilesh Rajbharti 5/16/03 Increased DHCP_TIMEOUT to 2 seconds.* Nilesh Rajbharti 5/16/03 Fixed SM_DHCP_BROADCAST logic* where UDPPut was called before setting* active socket.* Robert Sloan 5/29/03 Improved DHCP State machine to handle* NAK and renew existing IP address.* Nilesh Rajbharti 8/15/03 Modified _DHCPRecieve() to check for* chaddr field before accpting the packet.* Fixed DHCPTask() where it would not* reply to first OFFER.* Nilesh Rajbharti 3/1/04 Used tickDiff in DHCPTask() "bind"* state to adjust for irregular TICK_SECOND* Without this logic, actual lease time count* down may be incorrect.* Howard Schlunder5/11/06Fixed tickDiff usage, reducing *accumulated timing error. Fixed DHCP *state machine requesting IP 0.0.0.0 *after lease expiration.* Howard Schlunder6/01/06Added DHCPFlags.bits.bOfferReceived flag to *allow operation on networks with multiple*DHCP servers offering multiple addresses* Howard Schlunder8/01/06 Added DNS server option to DHCP request, *untested Host Name option to DHCP request* Howard Schlunder1/09/06Fixed a DHCP renewal not renewing lease time bug* Howard Schlunder3/16/07 Rewrote DHCP state machine********************************************************************/#define __DHCP_C#include "TCPIPConfig.h"#if defined(STACK_USE_DHCP_CLIENT)#include "TCPIP Stack/TCPIP.h"// Defines how long to wait before a DHCP request times out#define DHCP_TIMEOUT(2ul*TICK_SECOND)// Unique variables per interfacetypedef struct{UDP_SOCKEThDHCPSocket;// Handle to DHCP client socketSM_DHCPsmState;// DHCP client state machine variableunion{ struct { unsigned char bIsBound : 1;// Whether or not DHCP is currently bound unsigned char bEvent : 1;// Indicates to an external module that the DHCP client has been reset, has obtained new parameters via the DHCP client, or has refreshed a lease on existing ones unsigned char bOfferReceived : 1;// Whether or not an offer has been receivedunsigned char bDHCPServerDetected : 1;// Indicates if a DCHP server has been detectedunsigned char bUseUnicastMode : 1;// Indicates if the } bits; BYTE val;} flags;DWORD dwTimer;// Tick timer value used for triggering future events after a certain wait period.DWORDdwLeaseTime;// DHCP lease time remaining, in secondsDWORDdwServerID;// DHCP Server ID cacheIP_ADDRtempIPAddress;// Temporary IP address to use when no DHCP leaseIP_ADDRtempGateway;// Temporary gateway to use when no DHCP leaseIP_ADDRtempMask;// Temporary mask to use when no DHCP lease#if defined(STACK_USE_DNS)IP_ADDRtempDNS;// Temporary primary DNS serverIP_ADDRtempDNS2;// Temporary secondary DNS server#endif// Indicates which DHCP values are currently validunion{struct{char IPAddress:1;// Leased IP address is validchar Gateway:1;// Gateway address is validchar Mask:1;// Subnet mask is validchar DNS:1;// Primary DNS is validchar DNS2:1;// Secondary DNS is validchar HostName:1;// Host name is valid (not implemented)} bits;BYTE val;} validValues;} DHCP_CLIENT_VARS;BOOL DHCPClientInitializedOnce = FALSE;static BYTE _DHCPReceive(void);static void _DHCPSend(BYTE messageType, BOOL bRenewing);/***************************************************************************** Function:static void LoadState(BYTE vInterface) Summary:Saves the DHCPClient state information structure to the appropriate location and loads DHCPClient with the state information for the specified interface. Description:Saves the DHCPClient state information structure to the appropriate location and loads DHCPClient with the state information for the specified interface. Precondition:None Parameters:None Returns:None Remarks: This function does nothing when you only have one physical interface.***************************************************************************/#if NETWORK_INTERFACES > 1static DHCP_CLIENT_VARSDHCPClients[NETWORK_INTERFACES];static DHCP_CLIENT_VARS*SelectedDHCPClient;#define DHCPClient(*SelectedDHCPClient)#define LoadState(v)do(SelectedDHCPClient = &DHCPClients[v])while(0)#elsestatic DHCP_CLIENT_VARS DHCPClient;#define LoadState(v)#endif/***************************************************************************** Function:void DHCPInit(BYTE vInterface) Summary:Resets the DHCP client module for the specified interface. Description:Resets the DHCP client module, giving up any current lease, knowledge of DHCP servers, etc. for the specified interface. Precondition:None Parameters:vInterface - Interface number to initialize DHCP client state variables for. If you only have one interface, specify 0x00. Returns:None Remarks:This function may be called multiple times throughout the life of the application, if desired. ***************************************************************************/void DHCPInit(BYTE vInterface){BYTE i;// Upon the first call after POR, we must reset all handles to invalid so // that we don't inadvertently close someone else's handle.if(!DHCPClientInitializedOnce){DHCPClientInitializedOnce = TRUE;for(i = 0; i < NETWORK_INTERFACES; i++){LoadState(i);DHCPClient.hDHCPSocket = INVALID_UDP_SOCKET;}}LoadState(vInterface);if(DHCPClient.hDHCPSocket != INVALID_UDP_SOCKET){UDPClose(DHCPClient.hDHCPSocket);DHCPClient.hDHCPSocket = INVALID_UDP_SOCKET;}// Reset state machine and flags to default valuesDHCPClient.smState = SM_DHCP_GET_SOCKET;DHCPClient.flags.val = 0;DHCPClient.flags.bits.bUseUnicastMode = TRUE;// This flag toggles before use, so this statement actually means to start out using broadcast mode.DHCPClient.flags.bits.bEvent = TRUE;}/***************************************************************************** Function:void DHCPDisable(BYTE vInterface) Summary:Disables the DHCP Client for the specified interface. Description:Disables the DHCP client for the specified interface by sending the state machine to "SM_DHCP_DISABLED". If the interface was previously configured by DHCP, the configuration will continue to be used but the module will no longer preform any renewals. Precondition:None Parameters:vInterface - Interface number to disable the DHCP client on. If you only have one interface, specify 0x00. Returns:None Remarks:Since the interface continues using its old configuration, it is possible that the lease may expire and the DHCP server provide the IP to anotherclient. The application should replace the current IP address and otherconfiguration with static information following a call to this function.***************************************************************************/void DHCPDisable(BYTE vInterface){LoadState(vInterface);if(DHCPClient.hDHCPSocket != INVALID_UDP_SOCKET){UDPClose(DHCPClient.hDHCPSocket);DHCPClient.hDHCPSocket = INVALID_UDP_SOCKET;}DHCPClient.smState = SM_DHCP_DISABLED;}/***************************************************************************** Function:void DHCPEnable(BYTE vInterface) Summary:Enables the DHCP client for the specified interface. Description:Enables the DHCP client for the specified interface, if it is disabled. If it is already enabled, nothing is done. Precondition:None Parameters:vInterface - Interface number to enable the DHCP client on. If you only have one interface, specify 0x00. Returns:None***************************************************************************/void DHCPEnable(BYTE vInterface){LoadState(vInterface);if(DHCPClient.smState == SM_DHCP_DISABLED){DHCPClient.smState = SM_DHCP_GET_SOCKET;DHCPClient.flags.bits.bIsBound = FALSE;}}/***************************************************************************** Function:BOOL DHCPIsEnabled(BYTE vInterface) Summary:Determins if the DHCP client is enabled on the specified interface. Description:Determins if the DHCP client is enabled on the specified interface. Precondition:None Parameters:vInterface - Interface number to query. If you only have one interface, specify 0x00. Returns:None***************************************************************************/BOOL DHCPIsEnabled(BYTE vInterface){LoadState(vInterface);return DHCPClient.smState != SM_DHCP_DISABLED;}/***************************************************************************** Function:BOOL DHCPIsBound(BYTE vInterface) Summary:Determins if the DHCP client has an IP address lease on the specified interface. Description:Determins if the DHCP client has an IP address lease on the specified interface. Precondition:None Parameters:vInterface - Interface number to query. If you only have one interface, specify 0x00. Returns:TRUE - DHCP client has obtained an IP address lease (and likely other parameters) and these values are currently being used.FALSE - No IP address is currently leased***************************************************************************/BOOL DHCPIsBound(BYTE vInterface){LoadState(vInterface);return DHCPClient.flags.bits.bIsBound;}/***************************************************************************** Function:BOOL DHCPStateChanged(BYTE vInterface) Summary:Determins if the DHCP client on the specified interface has changed states or refreshed its IP address lease. Description:Determins if the DHCP client on the specified interface has changed states or refreshed its IP address lease. This function can be used to determinewhen to update an LCD or other display whenever the DHCP assigned IP address has potentially changed. Precondition:None Parameters:vInterface - Interface number to query. If you only have one interface, specify 0x00. Returns:TRUE - The IP address lease have been reliquished (due to reinitilization), obtained (first event), or renewed since the last call to DHCPStateChanged().FALSE - The DHCP client has not detected any changes since the last call to DHCPStateChanged().***************************************************************************/BOOL DHCPStateChanged(BYTE vInterface){LoadState(vInterface);if(DHCPClient.flags.bits.bEvent){DHCPClient.flags.bits.bEvent = 0;return TRUE;}return FALSE;}/***************************************************************************** Function:BOOL DHCPIsServerDetected(BYTE vInterface) Summary:Determins if the DHCP client on the specified interface has seen a DHCP server. Description:Determins if the DHCP client on the specified interface has seen a DHCP server. Precondition:None Parameters:vInterface - Interface number to query. If you only have one interface, specify 0x00. Returns:TRUE - At least one DHCP server is attached to the specified network interface.FALSE - No DHCP servers are currently detected on the specified network interface.***************************************************************************/BOOL DHCPIsServerDetected(BYTE vInterface){LoadState(vInterface);return DHCPClient.flags.bits.bDHCPServerDetected;}/***************************************************************************** Function:void DHCPTask(void) Summary:Performs periodic DHCP tasks for all interfaces. Description:This function performs any periodic tasks requied by the DHCP module, such as sending and receiving messages involved with obtaining andmaintaining a lease. Precondition:None Parameters:None Returns:None***************************************************************************/void DHCPTask(void){BYTE i;for(i = 0; i < NETWORK_INTERFACES; i++){LoadState(i);switch(DHCPClient.smState){case SM_DHCP_DISABLED:// When the module is disabled, do absolutely nothingbreak;case SM_DHCP_GET_SOCKET:// Open a socket to send and receive broadcast messages onDHCPClient.hDHCPSocket = UDPOpen(DHCP_CLIENT_PORT, NULL, DHCP_SERVER_PORT);if(DHCPClient.hDHCPSocket == INVALID_UDP_SOCKET)break;DHCPClient.smState = SM_DHCP_SEND_DISCOVERY;// No breakcase SM_DHCP_SEND_DISCOVERY:// Assume default IP Lease time of 60 seconds.// This should be minimum possible to make sure that if the// server did not specify lease time, we try again after this // minimum time.DHCPClient.dwLeaseTime = 60;DHCPClient.validValues.val = 0x00;DHCPClient.flags.bits.bIsBound = FALSE;DHCPClient.flags.bits.bOfferReceived = FALSE;// No point in wasting time transmitting a discovery if we are // unlinked. No one will see it. if(!MACIsLinked())break;// Ensure transmitter is ready to accept dataif(UDPIsPutReady(DHCPClient.hDHCPSocket) < 300u)break;// Toggle the BOOTP Broadcast flag to ensure compatibility with // bad DHCP servers that don't know how to handle broadcast // responses. This results in the next discovery attempt to be // made using the opposite mode.DHCPClient.flags.bits.bUseUnicastMode ^= 1;// Ensure that we transmit to the broadcast IP and MAC addresses// The UDP Socket remembers who it was last talking tomemset((void*)&UDPSocketInfo[DHCPClient.hDHCPSocket].remoteNode, 0xFF, sizeof(UDPSocketInfo[0].remoteNode));// Send the DHCP Discover broadcast_DHCPSend(DHCP_DISCOVER_MESSAGE, FALSE);// Start a timer and begin looking for a responseDHCPClient.dwTimer = TickGet();DHCPClient.smState = SM_DHCP_GET_OFFER;break;case SM_DHCP_GET_OFFER:// Check to see if a packet has arrivedif(UDPIsGetReady(DHCPClient.hDHCPSocket) < 250u){// Go back and transmit a new discovery if we didn't get an offer after 2 secondsif(TickGet() - DHCPClient.dwTimer >= DHCP_TIMEOUT)DHCPClient.smState = SM_DHCP_SEND_DISCOVERY;break;}// Let the DHCP server module know that there is a DHCP server // on this networkDHCPClient.flags.bits.bDHCPServerDetected = TRUE;// Check to see if we received an offerif(_DHCPReceive() != DHCP_OFFER_MESSAGE)break;DHCPClient.smState = SM_DHCP_SEND_REQUEST;// No breakcase SM_DHCP_SEND_REQUEST:if(UDPIsPutReady(DHCPClient.hDHCPSocket) < 258u)break;// Ensure that we transmit to the broadcast IP and MAC addresses// The UDP Socket remembers who it was last talking to, so // we must set this back to the broadcast address since the // current socket values are the unicast addresses of the DHCP // server.memset((void*)&UDPSocketInfo[DHCPClient.hDHCPSocket].remoteNode, 0xFF, sizeof(UDPSocketInfo[0].remoteNode));// Send the DHCP request message_DHCPSend(DHCP_REQUEST_MESSAGE, FALSE);// Start a timer and begin looking for a responseDHCPClient.dwTimer = TickGet();DHCPClient.smState = SM_DHCP_GET_REQUEST_ACK;break;case SM_DHCP_GET_REQUEST_ACK:// Check to see if a packet has arrivedif(UDPIsGetReady(DHCPClient.hDHCPSocket) < 250u){// Go back and transmit a new discovery if we didn't get an ACK after 2 secondsif(TickGet() - DHCPClient.dwTimer >= DHCP_TIMEOUT)DHCPClient.smState = SM_DHCP_SEND_DISCOVERY;break;}// Check to see if we received an offerswitch(_DHCPReceive()){case DHCP_ACK_MESSAGE:UDPClose(DHCPClient.hDHCPSocket);DHCPClient.hDHCPSocket = INVALID_UDP_SOCKET;DHCPClient.dwTimer = TickGet();DHCPClient.smState = SM_DHCP_BOUND;DHCPClient.flags.bits.bEvent = 1;DHCPClient.flags.bits.bIsBound = TRUE;if(DHCPClient.validValues.bits.IPAddress)AppConfig.MyIPAddr = DHCPClient.tempIPAddress;if(DHCPClient.validValues.bits.Mask)AppConfig.MyMask = DHCPClient.tempMask;if(DHCPClient.validValues.bits.Gateway)AppConfig.MyGateway = DHCPClient.tempGateway;#if defined(STACK_USE_DNS)if(DHCPClient.validValues.bits.DNS)AppConfig.PrimaryDNSServer.Val = DHCPClient.tempDNS.Val;AppConfig.SecondaryDNSServer.Val = 0x00000000ul;if(DHCPClient.validValues.bits.DNS2)AppConfig.SecondaryDNSServer.Val = DHCPClient.tempDNS2.Val;#endif//if(DHCPClient.validValues.bits.HostName)//memcpy(AppConfig.NetBIOSName, (void*)DHCPClient.tempHostName, sizeof(AppConfig.NetBIOSName));break;case DHCP_NAK_MESSAGE:DHCPClient.smState = SM_DHCP_SEND_DISCOVERY;break;}break;case SM_DHCP_BOUND:if(TickGet() - DHCPClient.dwTimer < TICK_SECOND)break;// Check to see if our lease is still valid, if so, decrement lease // timeif(DHCPClient.dwLeaseTime >= 2ul){DHCPClient.dwTimer += TICK_SECOND;DHCPClient.dwLeaseTime--;break;}// Open a socket to send and receive DHCP messages onDHCPClient.hDHCPSocket = UDPOpen(DHCP_CLIENT_PORT, NULL, DHCP_SERVER_PORT);if(DHCPClient.hDHCPSocket == INVALID_UDP_SOCKET)break;DHCPClient.smState = SM_DHCP_SEND_RENEW;// No breakcase SM_DHCP_SEND_RENEW:case SM_DHCP_SEND_RENEW2:case SM_DHCP_SEND_RENEW3:if(UDPIsPutReady(DHCPClient.hDHCPSocket) < 258u)break;// Send the DHCP request message_DHCPSend(DHCP_REQUEST_MESSAGE, TRUE);DHCPClient.flags.bits.bOfferReceived = FALSE;// Start a timer and begin looking for a responseDHCPClient.dwTimer = TickGet();DHCPClient.smState++;break;case SM_DHCP_GET_RENEW_ACK:case SM_DHCP_GET_RENEW_ACK2:case SM_DHCP_GET_RENEW_ACK3:// Check to see if a packet has arrivedif(UDPIsGetReady(DHCPClient.hDHCPSocket) < 250u){// Go back and transmit a new discovery if we didn't get an ACK after 2 secondsif(TickGet() - DHCPClient.dwTimer >= DHCP_TIMEOUT){if(++DHCPClient.smState > SM_DHCP_GET_RENEW_ACK3)DHCPClient.smState = SM_DHCP_SEND_DISCOVERY;}break;}// Check to see if we received an offerswitch(_DHCPReceive()){case DHCP_ACK_MESSAGE:UDPClose(DHCPClient.hDHCPSocket);DHCPClient.hDHCPSocket = INVALID_UDP_SOCKET;DHCPClient.dwTimer = TickGet();DHCPClient.smState = SM_DHCP_BOUND;DHCPClient.flags.bits.bEvent = 1;break;case DHCP_NAK_MESSAGE:DHCPClient.smState = SM_DHCP_SEND_DISCOVERY;break;}break;}}}/*****************************************************************************Function: void _DHCPReceive(void)Description: Receives and parses a DHCP message.Precondition: A DHCP message is waiting in the UDP buffer.Parameters: NoneReturns: One of the DCHP_TYPE* contants.***************************************************************************/static BYTE _DHCPReceive(void){/*********************************************************************DHCP PACKET FORMAT AS PER RFC 15410 1 2 30 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| op (1) | htype (1) | hlen (1) | hops (1) |+---------------+---------------+---------------+---------------+| xid (4) |+-------------------------------+-------------------------------+| secs (2) | flags (2) |+-------------------------------+-------------------------------+| ciaddr (4) |+---------------------------------------------------------------+| yiaddr (4) |+---------------------------------------------------------------+| siaddr (4) |+---------------------------------------------------------------+| giaddr (4) |+---------------------------------------------------------------+| || chaddr (16) || || |+---------------------------------------------------------------+| || sname (64) |+---------------------------------------------------------------+| || file (128) |+---------------------------------------------------------------+| || options (312) |+---------------------------------------------------------------+********************************************************************/BYTE v;BYTE i, j;BYTE type;BOOL lbDone;DWORD_VAL tempServerID;// Assume unknown message until proven otherwise.type = DHCP_UNKNOWN_MESSAGE;UDPGet(&v); // op// Make sure this is BOOT_REPLY.if ( v == BOOT_REPLY ){// Discard htype, hlen, hops, xid, secs, flags, ciaddr.for ( i = 0; i < 15u; i++ )UDPGet(&v);// Check to see if this is the first offerif(DHCPClient.flags.bits.bOfferReceived){// Discard offered IP address, we already have an offerfor ( i = 0; i < 4u; i++ )UDPGet(&v);}else{// Save offered IP address until we know for sure that we have it.UDPGetArray((BYTE*)&DHCPClient.tempIPAddress, sizeof(DHCPClient.tempIPAddress));DHCPClient.validValues.bits.IPAddress = 1;}// Ignore siaddr, giaddrfor ( i = 0; i < 8u; i++ )UDPGet(&v);// Check to see if chaddr (Client Hardware Address) belongs to us.for ( i = 0; i < 6u; i++ ){UDPGet(&v);if ( v != AppConfig.MyMACAddr.v[i])goto UDPInvalid;}// Ignore part of chaddr, sname, file, magic cookie.for ( i = 0; i < 206u; i++ )UDPGet(&v);lbDone = FALSE;do{// Get the Option number// Break out eventually in case if this is a malformed // DHCP message, ie: missing DHCP_END_OPTION markerif(!UDPGet(&v)){lbDone = TRUE;break;}switch(v){case DHCP_MESSAGE_TYPE:UDPGet(&v); // Skip len// Len must be 1.if ( v == 1u ){UDPGet(&type); // Get type// Throw away the packet if we know we don't need it (ie: another offer when we already have one)if(DHCPClient.flags.bits.bOfferReceived && (type == DHCP_OFFER_MESSAGE)){goto UDPInvalid;}}elsegoto UDPInvalid;break;case DHCP_SUBNET_MASK:UDPGet(&v); // Skip len// Len must be 4.if ( v == 4u ){// Check to see if this is the first offerif(DHCPClient.flags.bits.bOfferReceived){// Discard offered IP mask, we already have an offerfor ( i = 0; i < 4u; i++ )UDPGet(&v);}else{UDPGetArray((BYTE*)&DHCPClient.tempMask, sizeof(DHCPClient.tempMask));DHCPClient.validValues.bits.Mask = 1;}}elsegoto UDPInvalid;break;case DHCP_ROUTER:UDPGet(&j);// Len must be >= 4.if ( j >= 4u ){// Check to see if this is the first offerif(DHCPClient.flags.bits.bOfferReceived){// Discard offered Gateway address, we already have an offerfor ( i = 0; i < 4u; i++ )UDPGet(&v);}else{UDPGetArray((BYTE*)&DHCPClient.tempGateway, sizeof(DHCPClient.tempGateway));DHCPClient.validValues.bits.Gateway = 1;}}elsegoto UDPInvalid;// Discard any other router addresses.j -= 4;while(j--)UDPGet(&v);break;#if defined(STACK_USE_DNS)case DHCP_DNS:UDPGet(&j);// Len must be >= 4.if(j < 4u)goto UDPInvalid;// Check to see if this is the first offerif(!DHCPClient.flags.bits.bOfferReceived){UDPGetArray((BYTE*)&DHCPClient.tempDNS, sizeof(DHCPClient.tempDNS));DHCPClient.validValues.bits.DNS = 1;j -= 4;}// Len must be >= 4 for a secondary DNS server addressif(j >= 4u){// Check to see if this is the first offerif(!DHCPClient.flags.bits.bOfferReceived){UDPGetArray((BYTE*)&DHCPClient.tempDNS2, sizeof(DHCPClient.tempDNS2));DHCPClient.validValues.bits.DNS2 = 1;j -= 4;}}// Discard any other DNS server addresseswhile(j--)UDPGet(&v);break;#endif// case DHCP_HOST_NAME:// UDPGet(&j);// // Len must be >= 4.// if(j < 1u)//goto UDPInvalid;////// Check to see if this is the first offer//if(DHCPFlags.bits.bOfferReceived)//{// // Discard offered host name, we already have an offer// while(j--)// UDPGet(&v);//}//else//{//for(i = 0; j, i < sizeof(tempHostName); i++, j--)//{//UDPGet(&tempHostName[i]);//}//while(j--)//{//UDPGet(&v);//}//ValidValues.bits.HostName = 1;//}//// break;case DHCP_SERVER_IDENTIFIER:UDPGet(&v); // Get len// Len must be 4.if ( v == 4u ){UDPGet(&tempServerID.v[3]); // Get the idUDPGet(&tempServerID.v[2]);UDPGet(&tempServerID.v[1]);UDPGet(&tempServerID.v[0]);}elsegoto UDPInvalid;break;case DHCP_END_OPTION:lbDone = TRUE;break;case DHCP_IP_LEASE_TIME:UDPGet(&v); // Get len// Len must be 4.if ( v == 4u ){// Check to see if this is the first offerif(DHCPClient.flags.bits.bOfferReceived){// Discard offered lease time, we already have an offerfor ( i = 0; i < 4u; i++ )UDPGet(&v);}else{UDPGet(&(((BYTE*)(&DHCPClient.dwLeaseTime))[3]));UDPGet(&(((BYTE*)(&DHCPClient.dwLeaseTime))[2]));UDPGet(&(((BYTE*)(&DHCPClient.dwLeaseTime))[1]));UDPGet(&(((BYTE*)(&DHCPClient.dwLeaseTime))[0]));// In case if our clock is not as accurate as the remote // DHCP server's clock, let's treat the lease time as only // 96.875% of the value givenDHCPClient.dwLeaseTime -= DHCPClient.dwLeaseTime>>5;}}elsegoto UDPInvalid;break;default:// Ignore all unsupport tags.UDPGet(&j); // Get option lenwhile( j-- ) // Ignore option valuesUDPGet(&v);}} while( !lbDone );}// If this is an OFFER message, remember current server id.if ( type == DHCP_OFFER_MESSAGE ){DHCPClient.dwServerID = tempServerID.Val;DHCPClient.flags.bits.bOfferReceived = TRUE;}else{// For other types of messages, make sure that received// server id matches with our previous one.if ( DHCPClient.dwServerID != tempServerID.Val )type = DHCP_UNKNOWN_MESSAGE;}UDPDiscard(); // We are done with this packetreturn type;UDPInvalid:UDPDiscard();return DHCP_UNKNOWN_MESSAGE;}/***************************************************************************** Function:static void _DHCPSend(BYTE messageType, BOOL bRenewing) Description:Sends a DHCP message. Precondition:UDP is ready to write a DHCP packet. Parameters:messageType - One of the DHCP_TYPE constantsbRenewing - Whether or not this is a renewal request Returns:None***************************************************************************/static void _DHCPSend(BYTE messageType, BOOL bRenewing){BYTE i;IP_ADDRMyIP;UDPPut(BOOT_REQUEST); // opUDPPut(BOOT_HW_TYPE); // htypeUDPPut(BOOT_LEN_OF_HW_TYPE); // hlenUDPPut(0); // hopsUDPPut(0x12); // xid[0]UDPPut(0x23); // xid[1]UDPPut(0x34); // xid[2]UDPPut(0x56); // xid[3]UDPPut(0); // secs[0]UDPPut(0); // secs[1]UDPPut(DHCPClient.flags.bits.bUseUnicastMode ? 0x00: 0x80);// flags[0] with Broadcast flag clear/set to correspond to bUseUnicastModeUDPPut(0); // flags[1]// If this is DHCP REQUEST message, use previously allocated IP address.if((messageType == DHCP_REQUEST_MESSAGE) && bRenewing){UDPPutArray((BYTE*)&DHCPClient.tempIPAddress, sizeof(DHCPClient.tempIPAddress));}else{UDPPut(0x00);UDPPut(0x00);UDPPut(0x00);UDPPut(0x00);}// Set yiaddr, siaddr, giaddr as zeros,for ( i = 0; i < 12u; i++ )UDPPut(0x00);// Load chaddr - Client hardware address.UDPPutArray((BYTE*)&AppConfig.MyMACAddr, sizeof(AppConfig.MyMACAddr));// Set chaddr[6..15], sname and file as zeros.for ( i = 0; i < 202u; i++ )UDPPut(0);// Load magic cookie as per RFC 1533.UDPPut(99);UDPPut(130);UDPPut(83);UDPPut(99);// Load message type.UDPPut(DHCP_MESSAGE_TYPE);UDPPut(DHCP_MESSAGE_TYPE_LEN);UDPPut(messageType);if(messageType == DHCP_DISCOVER_MESSAGE){// Reset offered flag so we know to act upon the next valid offerDHCPClient.flags.bits.bOfferReceived = FALSE;}if((messageType == DHCP_REQUEST_MESSAGE) && !bRenewing){// DHCP REQUEST message must include server identifier the first time// to identify the server we are talking to.// _DHCPReceive() would populate "serverID" when it// receives DHCP OFFER message. We will simply use that// when we are replying to server.// If this is a renwal request, we must not include server id.UDPPut(DHCP_SERVER_IDENTIFIER);UDPPut(DHCP_SERVER_IDENTIFIER_LEN);UDPPut(((BYTE*)(&DHCPClient.dwServerID))[3]);UDPPut(((BYTE*)(&DHCPClient.dwServerID))[2]);UDPPut(((BYTE*)(&DHCPClient.dwServerID))[1]);UDPPut(((BYTE*)(&DHCPClient.dwServerID))[0]);}// Load our interested parameters// This is hardcoded list. If any new parameters are desired,// new lines must be added here.UDPPut(DHCP_PARAM_REQUEST_LIST);UDPPut(DHCP_PARAM_REQUEST_LIST_LEN);UDPPut(DHCP_SUBNET_MASK);UDPPut(DHCP_ROUTER);UDPPut(DHCP_DNS);UDPPut(DHCP_HOST_NAME);// Add requested IP address to DHCP Request Messageif( ((messageType == DHCP_REQUEST_MESSAGE) && !bRenewing) || ((messageType == DHCP_DISCOVER_MESSAGE) && DHCPClient.tempIPAddress.Val)){UDPPut(DHCP_PARAM_REQUEST_IP_ADDRESS);UDPPut(DHCP_PARAM_REQUEST_IP_ADDRESS_LEN);UDPPutArray((BYTE*)&DHCPClient.tempIPAddress, DHCP_PARAM_REQUEST_IP_ADDRESS_LEN);}// Add any new paramter request here.// End of Options.UDPPut(DHCP_END_OPTION);// Add zero padding to ensure compatibility with old BOOTP relays that discard small packets (<300 UDP octets)while(UDPTxCount < 300u)UDPPut(0); // Make sure we advirtise a 0.0.0.0 IP address so all DHCP servers will respond. If we have a static IP outside the DHCP server's scope, it may simply ignore discover messages.MyIP.Val = AppConfig.MyIPAddr.Val;if(!bRenewing)AppConfig.MyIPAddr.Val = 0x00000000;UDPFlush();AppConfig.MyIPAddr.Val = MyIP.Val;}#endif//#if defined(STACK_USE_DHCP_CLIENT)
