main.cpp

实现简单的ping程序功能

// main.cpp

// system header file
#include <iostream>
#include <stdio.h>
#include <winsock2.h>
#include <windows.h>

// self header file
#include "Header.h"

using namespace std;

void fill_icmp_data(char *, int); 
USHORT checksum(USHORT *, int); 
int decode_resp(char *,int ,struct sockaddr_in *); 

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 bread,datasize,times; 
	int fromlen = sizeof(from); 
	int timeout = 1000;
	int statistic = 0;  /* 用于统计结果 */  
	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]); 
	} 
	// create raw socket
	sockRaw = WSASocket(AF_INET,SOCK_RAW,IPPROTO_ICMP,NULL, 0,WSA_FLAG_OVERLAPPED);
	//
	//注：为了使用发送接收超时设置(即设置SO_RCVTIMEO, SO_SNDTIMEO)，
	//    必须将标志位设为WSA_FLAG_OVERLAPPED !
	// 
	if (sockRaw == INVALID_SOCKET)
	{ 
		fprintf(stderr,"WSASocket() failed: %d\n",WSAGetLastError()); 
		ExitProcess(STATUS_FAILED); 
	} 
	// 设置recv的超时
	bread = setsockopt(sockRaw,SOL_SOCKET,SO_RCVTIMEO,(char*)&timeout, 
		sizeof(timeout)); 
	if(bread == SOCKET_ERROR) 
	{ 
		fprintf(stderr,"failed to set recv timeout: %d\n",WSAGetLastError()); 
		ExitProcess(STATUS_FAILED); 
	} 
	timeout = 1000; 
	// 设置send的超时
	bread = setsockopt(sockRaw,SOL_SOCKET,SO_SNDTIMEO,(char*)&timeout, 
		sizeof(timeout)); 
	if(bread == SOCKET_ERROR) 
	{ 
		fprintf(stderr,"failed to set send timeout: %d\n",WSAGetLastError()); 
		ExitProcess(STATUS_FAILED); 
	} 


	memset(&dest,0,sizeof(dest)); 
	hp = gethostbyname(argv[1]);	//解析命令行参数，是否是主机名还是ip地址
	if (!hp){ 
		addr = inet_addr(argv[1]);	// 不是主机名
	} 
	if ((!hp) && (addr == INADDR_NONE) ) { 
		fprintf(stderr,"Unable to resolve %s\n",argv[1]);	// 也不是ip地址
		ExitProcess(STATUS_FAILED); 
	} 
	if (hp != NULL) 
		memcpy(&(dest.sin_addr),hp->h_addr,hp->h_length);	// 保存网络地址
	else 
		dest.sin_addr.s_addr = addr;	// 保存网络地址
	if (hp) 
		dest.sin_family = hp->h_addrtype; 
	else 
		dest.sin_family = AF_INET; 
	dest_ip = inet_ntoa(dest.sin_addr); // 保存目的ip地址


	// 
	//  atoi函数原型是: int atoi( const char *string );
	//  The return value is 0 if the input cannot be converted to an integer !
	//
	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)   /* 用户给出的数据包大小太大 */
		{
			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); 
	//
	//显示提示信息
	//
	fprintf(stdout,"\nPinging %s ....\n\n",dest_ip);
	
	for(int i=0;i<times;++i)	// 猜测
	{ 
		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); 
		} 
		bread = recvfrom(sockRaw,recvbuf,MAX_PACKET,0,(struct sockaddr*)&from,&fromlen); 
		if (bread == 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,bread,&from))
			statistic++; /* 成功接收的数目++ */
		Sleep(1000); 
	}
	
	/*
	Display the statistic result
	*/
	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;
}

/* 
The response is an IP packet. We must decode the IP header to locate 
the ICMP data 
*/ 
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 ; // number of 32-bit words *4 = bytes 
	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)); 
	memset(datapart, 'E', datasize - sizeof(IcmpHeader));
}