inettype.h

此代码是实现将lwip协议移植于51单片机的测试程序

union w{
	unsigned long dwords;
	struct {unsigned int high;unsigned int low;}words;
	struct {unsigned char byte3;unsigned char byte2;unsigned char byte1;unsigned char byte0;}bytes;
};

union ethernet_address_type{
	unsigned int words[3];
	unsigned char bytes[6];
};

union ip_address_type{
	unsigned long dwords;
	unsigned int words[2];
	unsigned char bytes[4];
};

union arp_table_type{
	unsigned char bytes[12];
	unsigned int words[6];
	struct{
		unsigned char status;
		unsigned char ttl;
		union ip_address_type ip_address;
		union ethernet_address_type ethernet_address;
	}arp;							//状态,生存时间,ip地址,以太网地址
};

//以太网帧                  
struct ethernet{
	unsigned char status;			//接收状态
	unsigned char nextpage;			//下一个页
	unsigned int length;			//以太网长度，以字节为单位
	unsigned int destnodeid[3];		//目的网卡地址
	unsigned int sourcenodeid[3];	//源网卡地址
	unsigned int protocal;			//下一层协议
	unsigned char packet[1500];		//包的内容
};

//IP包   仅当IHL=5时用 当不=5时作转换
struct ip{
	unsigned int head[9];			//以太网包头
	unsigned char verandihl;		//版本与头长度
	unsigned char typeofserver;		//服务类型
	unsigned int totallength;		//总长度
	unsigned int frameindex;		//IP帧序号
	unsigned int segment;			//分段标志
	unsigned char ttl;				//生存时间
	unsigned char protocal;			//下一层协议
	unsigned int crc;				//校验和
	unsigned int sourceip[2];		//源IP
	unsigned int destip[2];			//目的IP
	unsigned char packet[1484];		//IP包的内容
};

struct ippacket{
	unsigned int head[9];			//以太网包头
	unsigned int ippacket[750];		//IP包的内容
};
                
struct arp{
	unsigned int head[9];  			//以太网头
//arp报文的内容总长28字节
	unsigned int harewaretype;		//以太网为0x0001
    unsigned int protocaltype;		//ip 为0X0800
    unsigned char halength;			//=0X06
    unsigned char palength;			//=0X04
    unsigned int operation;			//操作  0X0001为请求 0X0002为应答 0X0003为反向地址请求 0X0004为反向地址应答
    unsigned int sourcenodeid[3];	//源网卡地址
	unsigned int sourceip[2];		//源IP地址
    unsigned int destnodeid[3];		//目的网卡地址
	unsigned int destip[2];			//目的IP地址
}; 

struct icmp{						//包含在IP包中，是IP的上层为0X01的应用
	unsigned int head[9];			//以太网头
    unsigned int iphead[10];		//IP头
    unsigned char type;				//0X08 PING请求 0X00 PING应答
    unsigned char option;			//0X00 PING
    unsigned int crc;      
    unsigned int id;
    unsigned int seq;
    unsigned char icmpdata[1472];
};

struct tcp{
	unsigned int head[9];
    unsigned int iphead[10];
    unsigned int sourceport;		//源端口
    unsigned int destport;			//目的端口
    unsigned long seqnumber;		//顺序号
	unsigned long acknumber;		//确认号
    unsigned char offset;			//数据偏移量
    unsigned char control;			//连接控制
    unsigned int window;			//流控
    unsigned int crc;				//校验和 ，包括伪头部，TCP头部，数据
    unsigned int urg;				//紧急指针
    unsigned char tcpdata[1460];	//TCP数据
};

struct udp{
	unsigned int head[9];
    unsigned int iphead[10];
    unsigned int sourceport;		//源端口
    unsigned int destport;			//目的端口
    unsigned int length;    
    unsigned int crc;				//校验和 ，包括伪头部，udp头部，数据
    unsigned char udpdata[1472];	//udp数据
};
             
//所有协议的共用体
union netcard{
	struct {unsigned char  bytebuf[1536];}bytes;
    struct{ unsigned int wordbuf[768];}words;
    struct ethernet etherframe;	
    struct arp arpframe;
    struct icmp icmpframe;
    struct tcp tcpframe;  
    struct ip ipframe;
	struct udp udpframe;
    struct ippacket ippacket;
};