DHCP客户端实现（初稿）

include "DHCP.h"#define _DHCP_C #define THIS_IS_DHCP#define DHCP_TIMEOUT(TICK)(2L * TICK_SECOND)#define DHCP_CLIENT_PORT(68u)#define DHCP_SERVER_PORT(67u)#define BOOT_REQUEST(1u)#define BOOT_REPLY(2u)#define HW_TYPE(1u)#define LEN_OF_HW_TYPE(6u)#define DHCP_MESSAGE_TYPE(53u)#define DHCP_MESSAGE_TYPE_LEN(1u)#define DHCP_UNKNOWN_MESSAGE(0u)#define DHCP_DISCOVER_MESSAGE(1u)#define DHCP_OFFER_MESSAGE(2u)#define DHCP_REQUEST_MESSAGE(3u)#define DHCP_DECLINE_MESSAGE(4u)#define DHCP_ACK_MESSAGE(5u)#define DHCP_NAK_MESSAGE(6u)#define DHCP_RELEASE_MESSAGE(7u)#define DHCP_SERVER_IDENTIFIER(54u)#define DHCP_SERVER_IDENTIFIER_LEN(4u)#define DHCP_PARAM_REQUEST_LIST(55u)#define DHCP_PARAM_REQUEST_LIST_LEN(2u)#define DHCP_PARAM_REQUEST_IP_ADDRESS(50u)#define DHCP_PARAM_REQUEST_IP_ADDRESS_LEN (4u)#define DHCP_SUBNET_MASK(1u)#define DHCP_ROUTER(3u)#define DHCP_IP_LEASE_TIME(51u)#define DHCP_END_OPTION(255u)#define HALF_HOUR(WORD)((WORD)60 * (WORD)30)#define INVALID_UDP_SOCKET(0xff)#define INVALID_UDP_PORT(0L)#define SIZE_OF_DHCPMES (548u) //标准DHCP报文字节大小DHCP_MES DHCPMes;APP_CONFIG AppConfig;SM_DHCP smDHCPState = SM_DHCP_INIT;static UDP_SOCKET DHCPSocket = INVALID_UDP_SOCKET;DHCP_STATE DHCPState = { 0x00 };static IP_ADDR DHCPServerID;//static DWORD_VAL DHCPLeaseTime;static IP_ADDR tempIPAddress;static IP_ADDR tempGateway;static IP_ADDR tempMask;INT8U SizeOfOptionsUsed; //DHCP报文options字段使用的字节INT8U SizeOfDHCPMesUsed;//DHCP报文全部字段使用字节长度static INT8U _DHCPReceive(void);static void _DHCPSend(INT8U messageType);/***********************************************************************************************************DHCPReset** Description: 对DHCP进行重置，设置相应的参数** Arguments : void** Returns : void ** Notes : 当服务器发回NAC报文时调用此函数************************************************************************************************************/void DHCPReset(void){// Do not reset DHCP if it was previously disabled.if ( smDHCPState == SM_DHCP_DISABLED )return;if ( DHCPSocket != INVALID_UDP_SOCKET )UDPClose(DHCPSocket);//？？？？？？？？？？？关闭套接字DHCPSocket = INVALID_UDP_SOCKET;smDHCPState = SM_DHCP_INIT;// DHCPBindCount = 0;DHCPState.bits.bIsBound = FALSE;}/***********************************************************************************************************DHCP_MesInit** Description: DHCP报文初始化函数:对除了options字段外其他部分进行初始化，，供DHCP_Send函数进行调用** Arguments : void** Returns : void ** Notes : 报文部分字段赋值为固定值************************************************************************************************************/viod DHCP_MesInit(viod){ INT8U i;DHCPMes.op=BOOT_REQUEST; DHCPMes.htype=HW_TYPE; DHCPMes.hlen=LEN_OF_HW_TYPE; DHCPMes.hops=0; DHCPMes.xid[0]=0x12; DHCPMes.xid[1]=0x34; DHCPMes.xid[2]=0x56; DHCPMes.xid[3]=0x78; DHCPMes.secs[0]=0; DHCPMes.secs[1]=0; DHCPMes.flags[0]=0x80; DHCPMes.flags[1]=0; for(i=0;i<4u;i++) {DHCPMes.ciaddr[i]=0x00;DHCPMes.yiaddr[i]=0x00;DHCPMes.siaddr[i]=0x00;DHCPMes.giaddr[i]=0x00; } DHCPMes.chaddr[0]=AppConfig.MyMACAddr.v[0]; DHCPMes.chaddr[1]=AppConfig.MyMACAddr.v[1]; DHCPMes.chaddr[2]=AppConfig.MyMACAddr.v[2]; DHCPMes.chaddr[3]=AppConfig.MyMACAddr.v[3]; DHCPMes.chaddr[4]=AppConfig.MyMACAddr.v[4]; DHCPMes.chaddr[5]=AppConfig.MyMACAddr.v[5]; for(i=6;i<16u;i++){DHCPMes.chaddr[i]=0x00; } for(i=0;i<64u;i++){DHCPMes.sname[i]=0x00; } for(i=0;i<128u;i++) {DHCPMes.file[i]=0x00; } }/* end of DHCP_MesInit *//***********************************************************************************************************DHCP_Task** Description: DHCP主任务模块，获取IP、子网掩码、默认网关 ,并存放在全局变量结构体AppConfig中，是DHCP任务核心函数** Arguments : void** Returns : void ** Notes : 租期未考虑************************************************************************************************************/viod DHCP_Task(viod){INT8U DHCPReValue;switch(smDHCPState){case SM_DHCP_INIT:tempIPAddress.val=0x0;//DHCP_MesInit();DHCPSocket=Socket_Create(); //？？？？？？？？？创建smDHCPState=SM_DHCP_BROADCAST;/* No break */case SM_DHCP_BROADCAST:if(DHCPState.bits.bIsBound) smDHCPState=SM_DHCP_REQUEST;else if( UDPIsPutReady(DHCPSocket) )//???????????????????{DHCP_Send(DHCP_DISCOVER_MESSAGE);smDHCPState=SM_DHCP_DISCOVER;}break;case SM_DHCP_DISCOVER:if ( UDPIsGetReady(DHCPSocket) ) //????????????????????????{if(DHCP_Receive()==DHCP_OFFER_MESSAGE){smDHCPState=SM_DHCP_REQUEST;}else break;}else break;case SM_DHCP_REQUEST:if( UDPIsPutReady(DHCPSocket) )//？？？？？？？套接字连接 成功{DHCP_Send(DHCP_REQUEST_MESSAGE);smDHCPState=SM_DHCP_BIND;}else break;case SM_DHCP_BIND:if(UDPIsGetReady(DHCPSocket)) //??????????????????????{DHCPReValue=DHCP_Receive();if(DHCPReValue==DHCP_NAK_MESSAGE){DHCP_Reset();return;}else if(DHCPReValue==DHCP_ACK_MESSAGE){UDPClose(DHCPSocket); //???????????DHCPSocket = INVALID_UDP_SOCKET;AppConfig.MyIPAddr=tempIPAddress;AppConfig.MyMask=tempMask;AppConfig.MyGateway=tempGateway;return;}}break;}/* end of switch*/}/*end of DHCP_Task*//***********************************************************************************************************DHCP_Send** Description: DHCP发送报文函数，根据传入的报文类型，产生相应的报文并发送** Arguments : INT8U messageType 报文类型 DHCP_DISCOVER_MESSAGE或DHCP_REQUEST_MESSAGE** Returns : void ** Notes : 租期未考虑************************************************************************************************************/void DHCP_Send(INT8U messageType){DHCP_MesInit();INT8U n=0;//options字段开始标志DHCPMes.options[n++]=99;DHCPMes.options[n++]=130;DHCPMes.options[n++]=83;DHCPMes.options[n++]=99;//设置options 53字段（报文类型信息）DHCPMes.options[n++]=DHCP_MESSAGE_TYPE;DHCPMes.options[n++]=DHCP_MESSAGE_TYPE_LEN;DHCPMes.options[n++]=messageType;if(messageType==DHCP_DISCOVER_MESSAGE){DHCPState.bits.bIsBound=FALSE;}if(messageType!=DHCP_DISCOVER_MESSAGE&&tempIPAddress.Val!=0x0000u){DHCPMes.options[n++]=DHCP_SERVER_IDENTIFIER;DHCPMes.options[n++]=DHCP_SERVER_IDENTIFIER_LEN;DHCPMes.options[n++]=DHCPServerID.v[0];DHCPMes.options[n++]=DHCPServerID.v[1];DHCPMes.options[n++]=DHCPServerID.v[2];DHCPMes.options[n++]=DHCPServerID.v[3];}//请求队列（子网掩码和默认网关）DHCPMes.options[n++]=DHCP_PARAM_REQUEST_LIST;DHCPMes.options[n++]=DHCP_PARAM_REQUEST_LIST_LEN;DHCPMes.options[n++]=DHCP_SUBNET_MASK;DHCPMes.options[n++]=DHCP_ROUTER;if(messageType==DHCP_REQUEST_MESSAGE){DHCPMes.options[n++]=DHCP_PARAM_REQUEST_IP_ADDRESS;DHCPMes.options[n++]=DHCP_PARAM_REQUEST_IP_ADDRESS_LEN;DHCPMes.options[n++]=tempIPAddress.v[0];DHCPMes.options[n++]=tempIPAddress.v[1];DHCPMes.options[n++]=tempIPAddress.v[2];DHCPMes.options[n++]=tempIPAddress.v[3];}DHCPMes.options[n++] = DHCP_END_OPTION; //options字段结束标志位SizeOfOptionsUsed=n+1;SizeOfDHCPMesUsed=SizeOfOptionsUsed+236;/*转换mbuf 数组结构，调用 socket 发送报文 代写。。。。。。。。。*/}//end of DHCP_Send()/*********************************************************************DHCP PACKET FORMAT AS PER RFC 154101230 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)|+—————————————————————+********************************************************************/ /***********************************************************************************************************DHCP_Receive** Description: 将接收到的报文的有效信息进行提取，并存放于全局变量的结构体** Arguments : void** Returns : (INT8U) type 报文类型 ** Notes : 租期未考虑************************************************************************************************************/ static INT8U DHCP_Receive(void) {/*???????????/mbf数据数组 转化成DHCP报文(DHCPMes)“““““`*/INT8U type,i,j;INT8U s=0;BOOL lbDone;IP_ADDR tempServerID;type=DHCP_UNKNOWN_MESSAGE;//make sure that the message comes from serverif(DHCPMes.op=BOOT_REPLY){if(!DHCPState.bits.bOffereReceived)//之前没有获得offer报文{tempIPAddress.Val=DHCPMes.yiaddr.Val; //将客户端被提供的IP存入teamIPAddress中}// Check to see if chaddr (Client Hardware Address) belongs to us.for(i=0;i<6u;i++){if(DHCPMes.chaddr.v[i] != AppConfig.MyMACAddr.v[i])goto UDPInvalid;}lbDone = FALSE;do{//Get the Option numberswitch(DHCPMes.options[s])case DHCP_MESSAGE_TYPE:s++;if(DHCPMes.options[s++]==1u){// s++;type=DHCPMes.options[s++];if(DHCPState.bits.bOfferReceived&&(type==DHCP_OFFER_MESSAGE)) //throw another offer when we already have one{goto UDPInvalid;}}else goto UDPInvalid;break;case DHCP_SUBNET_MASK:s++;if(DHCPMes.options[s++]==4u){if(!DHCPState.bits.bOfferReceived)// Check to see if this is the first offer{for(i=0;i<4;i++){tempMask[i]=DHCPMes.options[s++]; //将子网掩码存入tempMask结构体中}}}else goto UDPInvalid;break;case DHCP_ROUTER:s++;j= SHCPMes.options[s++];if(j>=4u) //大小为4的整数倍{if(!DHCPState.bits.bOfferReceived) // Check to see if this is the first offer{for(i=0;i<4;i++){tempGateway[i]=DHCPMes.options[s++]; //将网关存入tempGateway结构体中}}}elsegoto UDPInvalid;j-=4;while(j–)s++;//放弃其他 Router地址，指针加1break;case DHCP_SERVER_IDENTIFIER:s++;if(DHCPMes.options[s++]==4u){for(i=0;i<4;i++){tempServerID[i]=DHCPMes.options[s++]; //将服务器地址存放在tempServerID结构体中}}else goto UDPInvalid;break;case DHCP_END_OPTION:lbDone=TRUE;break;default: // Ignore all unsupport tags.s++;j=DHCPMes.options[s++]; //unsupport sizewhile(j–) s++;//Ignore all unsupport data}while( !lbDone ); //end of do}//end of if(DHCPMes.op=BOOT_REPLY)if(type==DHCP_OFFER_MESSAGE){DHCPServerID.Val=tempServerID.Val;DHCPState.bits.bOfferReceived=TRUE;}else{if(DHCPServerID.Val!=tempServerID.Val) //make sure that received server id matches with our previous one.{type = DHCP_UNKNOWN_MESSAGE ;}}/*处理完毕 待写。。。UDPDiscard();*/return type;UDPInvalid:/*处理完毕待写。。。。。UDPDiscard();*/return DHCP_UNKNOWN_MESSAGE;} //end of DHCP_Receive

****************************************************************************************************************8

你要以乐观的态度看待这个世界，你会发现世界是如此得美好