char *
strcat(char *pcDest, char *pcSrc)
{
assert((pcDest != NULL) && (pcSrc != NULL));
char * pcAddress = pcDest;
while(*pcDest != '\0')
{
pcDest ++;
}
while( (*pcDest++ = *pcSrc++) != '\0' )
{
}
return pcAddress;
}
http://blog.csdn.net/zpxili/article/details/11542041
http://blog.csdn.net/cbuttonst/article/details/7610801
上面两位兄弟的是发一个icmp包，就收一次。在我的电脑上运行的时候，
估计是我的网络中有回环，结果每次收到的都是刚刚发出去的icmp包，
用wireshark抓包又能够抓到正确的reply包。调试了好久，修改如下。
#ifndef CPING_HJ
#define CPING_HJ
#include <WinSock2.h>
#include <string>
typedef struct _SICMPHDR //icmp
{
unsigned char icmp_type;
unsigned char icmp_code;
unsigned short icmp_checksum;
unsigned short icmp_id;
unsigned short icmp_sequence;
unsigned long icmp_timestamp;
} ICMPHDR, *PICMPHDR;
typedef struct _SIPHDR //ip
{
UCHAR ip_hVerLen;
UCHAR ip_TOS;
USHORT ip_Length;
USHORT ip_ID;
USHORT ip_Flags;
UCHAR ip_TTL;
UCHAR ip_Protacol;
USHORT ip_Checksum;
ULONG ip_Source;
ULONG ip_Destination;
} IPHDR;
class CPing
{
public:
CPing();
~CPing();
void m_vPing();
private:
bool m_bSendData(char* pcBuf,int nBufLen,sockaddr_in* pstAddr);
bool m_bRecvData(char* pcBuf,int iBufLen,sockaddr_in* pstRecvAddr,int &riRecvLen);
void m_vInitICMP(PICMPHDR pstICMPHDR,int nSequence);
u_short m_usCheckSum(unsigned short *pusBuf,int iLen);
SOCKET m_iSocket;
};
#endif
#include "CPing.h"
#include <stdio.h>
#define DATA_SIZE 32
#define RECV_SIZE 1024
const int SEND_PACKAGE_SIZE = 30;
const int MAX_TIME = 3000; //ms
CPing::CPing()
{
WSADATA wsaData;
WORD wVersion;
wVersion = MAKEWORD(2,2);
int nRet = WSAStartup(wVersion,&wsaData);
if( nRet != 0 )
{
printf("WSAStartup failed with error: %d\n", nRet);
return;
}
if( LOBYTE(wsaData.wVersion) != 2 || HIBYTE(wsaData.wVersion) != 2 )
{
printf("Could not find a usable version of Winsock.dll\n");
WSACleanup();
return;
}
m_iSocket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
if( m_iSocket == INVALID_SOCKET )
{
printf("Socket err\n");
WSACleanup();
return;
}
}
CPing::~CPing()
{
if( INVALID_SOCKET != m_iSocket )
{
closesocket(m_iSocket);
}
WSACleanup();
}
void
CPing::m_vPing()
{
char acName[] = "www.vidagrid.com";
hostent *pstHost = gethostbyname(acName);
if( pstHost == NULL )
{
printf("CPing::m_vPing() gethostbyname err\n");
return;
}
sockaddr_in stDesAddr;
stDesAddr.sin_family = AF_INET;
stDesAddr.sin_port = htons(0);
stDesAddr.sin_addr = *((struct in_addr *)(pstHost->h_addr));
//stDesAddr.sin_addr.s_addr = inet_addr("172.17.92.110");
char acIPAddr[23] = {0};
strcpy(acIPAddr, inet_ntoa(stDesAddr.sin_addr));
printf("CPing::m_vPing() acIPAddr: %s\n", acIPAddr);
int iSendBufLen = sizeof(ICMPHDR) + DATA_SIZE;
char* pcIcmp = new char[iSendBufLen];
memset(pcIcmp, 0, iSendBufLen);
PICMPHDR pstIcmp = (PICMPHDR)pcIcmp;
int iSequence = 0;
int iCount = SEND_PACKAGE_SIZE;
while ( iCount-- > 0 )
{
m_vInitICMP(pstIcmp, iSequence++);
pstIcmp->icmp_checksum = m_usCheckSum((unsigned short*)pstIcmp,sizeof(ICMPHDR) + DATA_SIZE); //校验值
m_bSendData((char*)pstIcmp, iSendBufLen, &stDesAddr);
}
int iMinimum = 0;
int iMaximum = 0;
int iSumTime = 0;
iCount = 0;
DWORD dwStartTime = GetTickCount();
printf("\nPinging %s [%s] with 32 bytes of data:\n\n", acName, acIPAddr);
while( (GetTickCount()-dwStartTime) <= MAX_TIME)
{
sockaddr_in stRcvAddr;
char acBuf[RECV_SIZE] = {0};
int iRecvLen = 0;
m_bRecvData(acBuf, sizeof(acBuf), &stRcvAddr, iRecvLen);
int iHeadLen = sizeof(IPHDR) + sizeof(ICMPHDR) + DATA_SIZE;
if( iRecvLen < iHeadLen )
{
printf("CPing::m_vPing() tool few data~\n\n");
continue;
}
IPHDR *ipHead = (IPHDR *)acBuf;
PICMPHDR icmpRecv = (PICMPHDR) (acBuf + sizeof(IPHDR) );
if( icmpRecv->icmp_type != 0 )
{
printf("CPing::m_vPing() Icmp Type err~, 0x%x\n\n", icmpRecv->icmp_type);
continue;
}
if( icmpRecv->icmp_id != GetCurrentProcessId() )
{
printf("CPing::m_vPing() Icmp ID err~\n\n");
continue;
}
int iCurUsedTime = GetTickCount() - icmpRecv->icmp_timestamp;
printf("Reply from %s: bytes=%d time=%ums TTL=%d\n",
inet_ntoa(stRcvAddr.sin_addr),
DATA_SIZE,
iCurUsedTime,
ipHead->ip_TTL);
iSumTime += iCurUsedTime;
if(iCount != 0)
{
if(iCurUsedTime<iMinimum) iMinimum = iCurUsedTime;
else if(iCurUsedTime>iMaximum) iMaximum = iCurUsedTime;
}
else
{
iMinimum = iCurUsedTime;
iMaximum = iCurUsedTime;
}
iCount++;
}
//show statistics
printf("\nPing statistics for %s:\n", acIPAddr);
printf("\tPackets: Sent = %d, Received = %d, Lost = %d (%.2lf%% loss),\n",
SEND_PACKAGE_SIZE, iCount, SEND_PACKAGE_SIZE-iCount, ((double)(SEND_PACKAGE_SIZE-iCount))/SEND_PACKAGE_SIZE*100 );
printf("Approximate round trip times in milli-seconds:\n");
printf("\tMinimum = %dms, Maximum = %dms, Average = %dms\n",
iMinimum, iMaximum, iSumTime/iCount);
delete pcIcmp;
getchar();
}
bool
CPing::m_bSendData(char* pcBuf,int iBufLen,sockaddr_in* pstAddr)
{
printf("CPing::m_bSendData() \n");
if( pstAddr == NULL )
{
printf("CPing::m_bSendData() pstAddr == NULL\n");
return false;
}
int iTimeout = 1000;
int iRet = setsockopt(m_iSocket, SOL_SOCKET, SO_SNDTIMEO, (char*)&iTimeout, sizeof(int));
if( iRet == SOCKET_ERROR )
{
printf("CPing::m_bSendData() setsockopt SO_SNDTIMEO err\n");
return false;
}
iRet = sendto(m_iSocket, pcBuf, iBufLen, 0, (sockaddr*)pstAddr, sizeof(sockaddr));
if( iRet == SOCKET_ERROR )
{
if (WSAETIMEDOUT == WSAGetLastError())
{
printf("CPing::m_bSendData() timeout err\n");
return false;
}
else
{
printf("CPing::m_bSendData() sendto err\n");
return false;
}
}
return true;
}
bool
CPing::m_bRecvData(char* pcBuf,int iBufLen,sockaddr_in* pstRecvAddr,int &riRecvLen)
{
printf("CPing::m_bRecvData() \n");
if( INVALID_SOCKET == m_iSocket )
{
printf("CPing::m_bRecvData() INVALID_SOCKET\n");
return false;
}
int iTimeout = 1000;
int iRet = setsockopt(m_iSocket, SOL_SOCKET, SO_RCVTIMEO , (char*)&iTimeout, sizeof(int));
if( SOCKET_ERROR == iRet )
{
printf("CPing::m_bRecvData() setsockopt SO_RCVTIMEO error\n");
return false;
}
int nAddrLen = sizeof(sockaddr);
iRet = recvfrom(m_iSocket, pcBuf, iBufLen, 0, (sockaddr*)pstRecvAddr, &nAddrLen);
if( SOCKET_ERROR == iRet )
{
if (WSAETIMEDOUT == WSAGetLastError())
{
printf("CPing::m_bRecvData() timeout err\n");
return false;
}
else
{
printf("CPing::m_bRecvData() recvfrom err\n");
return false;
}
}
riRecvLen = iRet;
return true;
}
void
CPing::m_vInitICMP(PICMPHDR pstICMPHDR,int iSequence)
{
if( pstICMPHDR == NULL )
return;
pstICMPHDR->icmp_type = 8; //request
pstICMPHDR->icmp_code = 0; //icmp request
pstICMPHDR->icmp_sequence = iSequence;
pstICMPHDR->icmp_id = (unsigned short)GetCurrentProcessId();
pstICMPHDR->icmp_timestamp = GetTickCount();
pstICMPHDR->icmp_checksum = 0; //校验值
}
unsigned short
CPing::m_usCheckSum(unsigned short *pusBuf,int iLen)
{
USHORT cksum=0;
while(iLen>1)
{
cksum+=*pusBuf++;
iLen-=sizeof(USHORT);
}
if(iLen)
{
cksum+=*pusBuf++;
}
cksum=(cksum>>16)+(cksum&0xffff);
cksum+=(cksum>>16);
return (USHORT)(~cksum);
}
//main.cpp
#include "CPing.h"
#include <stdio.h>
#include <winsock2.h>
#include <iostream>
#include <windows.h>
using namespace std;
#pragma comment(lib, "ws2_32.lib")
int main()
{
CPing oPing;
oPing.m_vPing();
return 0;
}
当 icmp_type==8 时，这是一个请求包（ECHO包）。
当 icmp_type==0 时，这是一个响应消息报（ECHO REPLY包），就是对请求包的回应。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main ()
{
char a = 'a' ;
char b = 'b' ;
char c = 'c' ;
char d = 'd' ;
char ac [4] = { a , b , c , d };
int i ;
memcpy (& i , ac , 4);
printf ( "0x%x\n" , i );
int iNum = ( a <<24) + ( b <<16) + ( c <<8) + d ;
printf ( "iNum: 0x%x\n" , iNum );
getchar ();
}
输出如下:
0x64636261
iNum: 0x61626364
CRITICAL_SECTION g_cs;
InitializeCriticalSectionAndSpinCount(&g_cs, 400);
EnterCriticalSection(&g_cs);
LeaveCriticalSection(&g_cs);
DeleteCriticalSection(&g_cs);
#include <windows.h>
#include <stdio.h>
CRITICAL_SECTION g_cs;
int main()
{
InitializeCriticalSectionAndSpinCount(&g_cs, 400);
printf("Before enter\n");
EnterCriticalSection(&g_cs);
printf("Enter 1\n");
EnterCriticalSection(&g_cs);
printf("Enter 2\n");
LeaveCriticalSection(&g_cs);
printf("Leave 1\n");
LeaveCriticalSection(&g_cs);
printf("Leave 2\n");
DeleteCriticalSection(&g_cs);
return 0;
}
test.h
#ifndef TEST_H
#define TEST_H
#endif
#define FALSE 0
#define TRUE (!FALSE)
#define MAX_NO_OF_STUDENT 100
const int MAX_NO_OF_STUDENT = 100;
int m_iGetValues();
m_ : a member of a class
i : returns a int
long m_lGetValues();
m_ : a member of a class
l : returns a long
int * m_piGetValus();
m_ : a member of a class
p : returns pointer
i : a int pointer
void * m_pvDoSomething();
m_ : a member of a class
p : returns pointer
v : a void pointer
unsigned char ucGetValues();
uc : This returns unsigned char
bool bIsRunning();
b : returns a bool
void m_vSetValues(int iNum);
m_ : a member of a class
v : there is no return value
If the function is not a member of a class, then ‘m_’ prefix is not used.Example:
//global function
int g_iGetValues();
g_ : a global functions
i : returns a int
//在 int变量 的最前面加上一个小写的i,之后每个单词的第一个字母大写
int iNum;
int iNoOfVariables;
//在数组的最前面加上a(array),然后紧接着一个数组类型的字母。
char acFileName[128]; ac代表一个字符类型的数组
int aiNum[128]; ai代表这是一个int类型的数组
char *apcFileName[128]; 这是一个数组，数组中保存着128个char类型的指针
char (*pacFileName)[128]; 这是一个指针，
//在变量的最前面加上 m_， 代表这是一个类或者是一个结构体中的成员变量。
typedef struct _SNode {
char * m_pcName; //m_:结构体成员; pc:指向char类型的指针
struct _SNode * m_pstNext; //m_结构体成员; pst:指向struct类型的指针
}SNode;
#include <stdio.h>
#define N 10000
int main()
{
int i;
int j;
int a[N];
for (i = 2; i < N; i++) a[i] = 1;
for (i = 2; i < N; i++)
{
if(a[i])
{
for (j = i; i*j < N; j++)
a[i*j] = 0;
}
}
for (i = 2; i < N; i++)
if(a[i])
printf("%4d ", i);
printf("\n");
return 0;
}