ping命令的实现

[c++]代码库

#pragma pack(4)
#include   <winsock2.h> 
#include   <stdlib.h>
#include   <stdio.h>

#define ICMP_ECHO 8 
#define ICMP_ECHOREPLY 0 
#define ICMP_MIN 8 

//#pragma comment(lib,"ws2_32.lib")

//IP数据报头
typedef struct iphdr 
{ 
	unsigned int h_len:4;          // length of the header  头部长 
	unsigned int version:4;        // Version of IP IP版本 一般都为IPV4
	unsigned char tos;             // Type of service 服务类型
	unsigned short total_len;      // total length of the packet 数据包总长度
	unsigned short ident;          // unique identifier .唯一标识符 
	unsigned short frag_and_flags; // flags 标志 
	unsigned char ttl;			   //生存时间TTL
	unsigned char proto;           // protocol (TCP, UDP etc) // 上层协议
	unsigned short checksum;       // IP checksum IP校验总和
	unsigned int sourceIP;		   //源IP地址
	unsigned int destIP;		   //目的IP地址
}IpHeader; 

// ICMP header 定义ICMP 头部
typedef struct icmphdr 
{ 
	BYTE i_type;    
	BYTE i_code;    
	USHORT i_cksum; 
	USHORT i_id;    
	USHORT i_seq;  
	ULONG timestamp; 
}IcmpHeader; 

#define STATUS_FAILED 0xFFFF    
#define DEF_PACKET_SIZE    32
#define DEF_PACKET_NUMBER  4   
#define MAX_PACKET 1024       
#define xmalloc(s) HeapAlloc(GetProcessHeap(),HEAP_ZERO_MEMORY,(s)) 
#define xfree(p) HeapFree (GetProcessHeap(),0,(p))


 
USHORT checksum(USHORT *buffer, int size);

int decode_resp(char *buf, int bytes,struct sockaddr_in *from);
void fill_icmp_data(char * icmp_data, int datasize);


void Usage(char *progname)
{ 
	fprintf(stderr,"Usage:\n"); 
	fprintf(stderr,"%s [number of packets] [data_size]\n",progname); 
	fprintf(stderr,"datasize can be up to 1Kb\n"); 
	ExitProcess(STATUS_FAILED); 
} 


int main(int argc, char *argv[])
{ 
	WSADATA wsaData;  
	SOCKET sockRaw; 
	struct sockaddr_in dest,from; 
	struct hostent *hp;   
	int result,datasize,times; 
	int fromlen = sizeof(from); 
	int timeout = 1000; 
	int statistic = 0; 
	char *dest_ip; 
	char *icmp_data; 
	char *recvbuf; 
	unsigned int addr=0; 
	USHORT seq_no = 0; 
	if (WSAStartup(MAKEWORD(2,1),&wsaData) != 0)
	{ 
		fprintf(stderr,"WSAStartup failed: %d\n",GetLastError()); 
		ExitProcess(STATUS_FAILED); 
	} 

	if (argc <2 ) 
	{ 
		Usage(argv[0]); 
	} 
	sockRaw = WSASocket(AF_INET,SOCK_RAW,IPPROTO_ICMP,NULL, 0,WSA_FLAG_OVERLAPPED);

	if (sockRaw == INVALID_SOCKET) 
	{ 
		fprintf(stderr,"WSASocket() failed: %d\n",WSAGetLastError()); 
		ExitProcess(STATUS_FAILED); 
	} 

	result = setsockopt(sockRaw,SOL_SOCKET,SO_RCVTIMEO,(char*)&timeout,sizeof(timeout)); 

	if(result == SOCKET_ERROR) 
	{ 
		fprintf(stderr,"failed to set recv timeout: %d\n",WSAGetLastError()); 
		ExitProcess(STATUS_FAILED); 
	} 
	timeout = 1000; 

	result = setsockopt(sockRaw,SOL_SOCKET,SO_SNDTIMEO,(char*)&timeout,sizeof(timeout)); 

	if(result == SOCKET_ERROR) 
	{ 
		fprintf(stderr,"failed to set send timeout: %d\n",WSAGetLastError()); 
		ExitProcess(STATUS_FAILED); 
	} 
	memset(&dest,0,sizeof(sockaddr_in)); /***********/

	hp = gethostbyname(argv[1]); 
	if (!hp)
	{ 
		addr = inet_addr(argv[1]); 
	} 

	if ((!hp) && (addr == INADDR_NONE) ) 
	{ 
		fprintf(stderr,"Unable to resolve %s\n",argv[1]); 
		ExitProcess(STATUS_FAILED); 
	} 

	if (hp != NULL) 
		memcpy(&(dest.sin_addr),hp->h_addr,hp->h_length);
	else 
		dest.sin_addr.s_addr = addr; 

	if (hp) 
		dest.sin_family = hp->h_addrtype; 
	else 
		dest.sin_family = AF_INET; 
		dest_ip = inet_ntoa(dest.sin_addr); 


	if(argc>2)
	{
		times=atoi(argv[2]);
		if(times == 0)
			times=DEF_PACKET_NUMBER;
	}
	else
		times=DEF_PACKET_NUMBER;

	if (argc >3) 
	{ 
		datasize = atoi(argv[3]); 
	
			if (datasize == 0) 
				datasize = DEF_PACKET_SIZE;

	 if (datasize >1024)  
	 {
		fprintf(stderr,"WARNING : data_size is too large !\n");
		datasize = DEF_PACKET_SIZE; 
	 }
	} 
	else 
		datasize = DEF_PACKET_SIZE; 
		datasize += sizeof(IcmpHeader); 
		icmp_data = (char*)xmalloc(MAX_PACKET); 
		recvbuf = (char*)xmalloc(MAX_PACKET); 
		if (!icmp_data) 
		{ 
			fprintf(stderr,"HeapAlloc failed %d\n",GetLastError()); 
			ExitProcess(STATUS_FAILED); 
		} 

	memset(icmp_data,0,MAX_PACKET); 

	fill_icmp_data(icmp_data,datasize); 

	fprintf(stdout,"\nPinging %s with %d of data\n\n",dest_ip,datasize);


	for(int i=0; i<times;i++)
	{ 
		int bwrote; 
	
		((IcmpHeader*)icmp_data)->i_cksum = 0; 
		((IcmpHeader*)icmp_data)->timestamp = GetTickCount(); 
		((IcmpHeader*)icmp_data)->i_seq = seq_no++; 
		((IcmpHeader*)icmp_data)->i_cksum = checksum((USHORT*)icmp_data,datasize);

		bwrote = sendto(sockRaw,icmp_data,datasize,0,(struct sockaddr*)&dest,sizeof(dest));

		if (bwrote == SOCKET_ERROR)
		{ 
			if (WSAGetLastError() == WSAETIMEDOUT) 
			{ 
				printf("Request timed out.\n"); 
				continue; 
			} 
			fprintf(stderr,"sendto failed: %d\n",WSAGetLastError()); 
			ExitProcess(STATUS_FAILED); 
		} 
		if (bwrote < datasize ) 
		{ 
			fprintf(stdout,"Wrote %d bytes\n",bwrote); 
		} 

		result = recvfrom(sockRaw,recvbuf,MAX_PACKET,0,(struct sockaddr*)&from,&fromlen);
	
		if (result == SOCKET_ERROR)
		{ 
			if (WSAGetLastError() == WSAETIMEDOUT) 
			{ 
				printf("Request timed out.\n"); 
				continue; 
			} 
			fprintf(stderr,"recvfrom failed: %d\n",WSAGetLastError()); 
			ExitProcess(STATUS_FAILED); 
		} 
	
		if(!decode_resp(recvbuf,result,&from))
			statistic++; 
		Sleep(1000); 
	}
 

	fprintf(stdout,"\nPing statistics for %s \n",dest_ip);
	fprintf(stdout,"Packets: Sent = %d,Received = %d, Lost = %d (%2.0f%% loss)\n",times,
		    statistic,(times-statistic),(float)(times-statistic)/times*100);

	WSACleanup();
	return 0; 
} 

int decode_resp(char *buf, int bytes,struct sockaddr_in *from) 
{ 
	IpHeader *iphdr; 
	IcmpHeader *icmphdr; 
	unsigned short iphdrlen; 
	iphdr = (IpHeader *)buf;   
	
	iphdrlen = (iphdr->h_len) * 4 ; 
	if (bytes < iphdrlen + ICMP_MIN)   
	{ 
		printf("Too few bytes from %s\n",inet_ntoa(from->sin_addr)); 
	} 
	
	icmphdr = (IcmpHeader*)(buf + iphdrlen);
	if (icmphdr->i_type != ICMP_ECHOREPLY) 
	{ 
		fprintf(stderr,"non-echo type %d recvd\n",icmphdr->i_type); 
		return 1; 
	} 
	
	if (icmphdr->i_id != (USHORT)GetCurrentProcessId()) 
	{ 
		fprintf(stderr,"someone else's packet!\n"); 
		return 1; 
	} 
	printf("%d bytes from %s:",bytes, inet_ntoa(from->sin_addr)); 
	printf(" icmp_seq = %d. ",icmphdr->i_seq); 
	printf(" time: %d ms ",GetTickCount()-icmphdr->timestamp); 
	printf("\n");
	return 0; 
} 

USHORT checksum(USHORT *buffer, int size) 
{ 
	unsigned long cksum=0; 
	
	while(size >1) 
	{ 
		cksum+=*buffer++; 
		size -=sizeof(USHORT); 
	} 
	  
	if(size) 
	{ 
		cksum += *(UCHAR*)buffer; 
	} 
	cksum = (cksum >> 16) + (cksum & 0xffff); 
	cksum += (cksum >>16);   
	return (USHORT)(~cksum); 
} 
/* Helper function to fill in various stuff in our ICMP request. */ 

void fill_icmp_data(char * icmp_data, int datasize)
{ 
	IcmpHeader *icmp_hdr; 
	char *datapart; 
	icmp_hdr = (IcmpHeader*)icmp_data; 
	icmp_hdr->i_type = ICMP_ECHO; 
	icmp_hdr->i_code = 0; 
	icmp_hdr->i_id = (USHORT)GetCurrentProcessId(); 
	icmp_hdr->i_cksum = 0; 
	icmp_hdr->i_seq = 0; 
	datapart = icmp_data + sizeof(IcmpHeader); 
 
	/* Place some junk in the buffer. */
	
	memset(datapart,'E', datasize - sizeof(IcmpHeader));  
} 

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