winpcap实现从TCP三次握手到发送http请求

之前的文章我都是贴出了协议的格式，对具体字段没有具体说明，今天在这里补充一下。

/*                       IP报文格式0            8           16                        32+------------+------------+-------------------------+| ver + hlen |  服务类型  |         总长度          |+------------+------------+----+--------------------+|           标识位        |flag|   分片偏移(13位)   |+------------+------------+----+--------------------+|  生存时间  | 高层协议号 |       首部校验和        |+------------+------------+-------------------------+|                   源 IP 地址                      |+---------------------------------------------------+|                  目的 IP 地址                     |+---------------------------------------------------+*/

版本号（Version）字段标明了IP 协议的版本号，目前的协议版本号为4，下一代IP 协议的版本号为6，占4位。

普通的 IP 头部长度为20 个字节，不包含IP 选项字段，注意：这里的头部长度是以4字节即32位为单位的，所以真正的IP报头长度应该是该值 * 4。占4位

位的服务类型（TOS，Type of Service）字段包括一个3 位的优先权字段（COS，Class of Service），4 位TOS 字段和1 位未用位。4 位TOS 分别代表最小时延、最大吞吐量、最高可靠性和最小费用。一般是置0的。

总长度（Total length）是整个IP 数据报长度，如果上层是TCP协议，则总长度 = IP报头长度 + TCP报头长度 + 数据长度。

标识符（Identification）字段唯一地标识主机发送的每一份数据报。通常每发送一份报文它的值就会加1，我试验的时候没有加一，服务器也能响应。

生存时间（TTL，Time to Live）字段设置了数据包可以经过的路由器数目。一旦经过一个路由器，TTL 值就会减1，当该字段值为0 时，数据包将被丢弃，所以你可以将该置设成最大0xFF。

高层协议号：IP是网络层协议，要为传输层服务，一般来说高层协议有TCP、UDP，还可以是ICMP，因为ICMP也是用IP包发送的。TCP 为6，UDP为17，ICMP为1。

首部校验和（Head checksum）：IP 头部的校验和，如果有选项字段，那就要一起校验，在计算校验和时一定先要将其值为0。

最后两项是源主机ip地址和目标主机ip地址。

/*                     TCP 报文0                       16                       32+------------------------+-------------------------+|      源端口地址        |      目的端口地址       |+------------------------+-------------------------+|                      序列号                      |+--------------------------------------------------+|                      确认号                      |+------+--------+--------+-------------------------+|HLEN/4| 保留位 |控制位/6|         窗口尺寸        |+------+--------+--------+-------------------------+|         校验和         |         应急指针        |+------------------------+-------------------------+*/

源端口号：标识主机上发起传送的应用程序；

目的端口：标识主机上传送要到达的应用程序。

顺序号：用来标识从TCP源端向TCP目标端发送的数据字节流，它表示在这个报文段中的第一个数据字节。

确认号：只有ACK标志为1时，确认号字段才有效。它包含目标端所期望收到源端的下一个数据字节。

头部长度：TCP报头的长度，单位是4字节即32位，如果没有选项字段，则TCP报头为20字节，这个地方写20 / 4 = 5。这个字段也叫数据偏移量，表示数据开始的地方。

预留：由跟在数据偏移字段后的6位构成，预留位通常为0。

标志位：（U、A、P、R、S、F）：占6位。从左到右依次是URG、ACK、PSH、RST、SYN、FIN。各位的含义如下：
　　URG：紧急指针（urgent pointer）有效。
　　ACK：确认序号有效。
　　PSH：接收方应该尽快将这个报文段交给应用层。
　　RST：重建连接。
　　SYN：发起一个连接。
　　FIN：释放一个连接。
窗口大小：占16比特。此字段用来进行流量控制。单位为字节数，这个值是本机期望一次接收的字节数。

TCP校验和：TCP报头校验和。注意，这个地方要校验的不仅仅是TCP报头数据，而是伪报头 + TCP报头 + TCP数据 这三个数据，很多人在这个地方少了。

紧急指针字段：占16比特。它是一个偏移量，和序号字段中的值相加表示紧急数据最后一个字节的序号。

TCP伪报头

struct PSDTCP_HEADER{ byte srcIpAddr[4];     //Source IP address; 32 bitsbyte dstIpAddr[4];     //Destination IP address; 32 bits byte padding;          //paddingbyte protocol;         //Protocol; 8 bitsbyte tcpLen[2];        //TCP length; 16 bits} ;

上面说了，在计算TCP校验和时需要伪报头，主要是要用源 /目的主机的IP地址和运输层网络协议号。其实按照协议分层来说，TCP所在的传输层应该和IP地址所在的网络层是分开的，现在传输层要访问网络层报文中的IP地址，好像违反了规定。

最后就是以太网头了如下：

struct ETHERNET_HEADER{  byte dstMacAddr[6];byte srcMacAddr[6];byte ethernetType[2];};

以太网头主要是源主机和目标主机的mac地址以及协议，比如IP或者ARP，这个地方再强调一点，我们很容易获取源主机的mac地址，但对目标主机就不一定了，假如只是做试验，我们可能知道，但假如我们真的要给外网服务器发送，那就不行了，我们不可能知道百度服务器的mac地址，所以在给外网发送时，目标主机的mac地址应该写网关的mac地址，直接发给网关。网上很多帖子在这个地方说的都很模糊，有些甚至是直接全写0xFF。

我们闭着眼可以画出TCP三次握手的连接图，但是你有没有想过，当经过三次握手建立连接后，数据时怎么传递的，在传递数据的时候那几个标志位是什么，是SYN还是ACK，这个网上资料很少，我是先抓包研究的，最后结果如下：

经抓包分析得知，最后发送数据时发的是ack和psh包，至于为什么是ack和psh，我现在还不知道，等接下来慢慢研究。

我连的是百度的服务器，怎么获取百度服务器的ip地址，我别的文章中有，目的端口是80，源端口是随机的。

int main(){srand(time(0));unsigned short srcPort = rand()%65535;//6382;const char *lpszSrcIp = "10.126.72.37";const char *lpszDstIp = "112.80.248.73";const byte srcMac[] = {0x90, 0x2B, 0x34, 0x9A, 0xC2, 0xBB};//主机macconst byte dstMac[] = {0x00, 0x00, 0x5e, 0x00, 0x01, 0x48}; //网关macchar szError[1024];const char *lpszAdapterName = "\\Device\\NPF_{1DDB19E0-EC33-46E2-ACB5-085E87EF6489}";pcap_t *handle = pcap_open_live(lpszAdapterName, 65536, 1, 1000, szError );if ( NULL == handle ) return 0;TCP_HEADER tcpHeader;memset(&tcpHeader, 0, sizeof tcpHeader );*(unsigned short *)tcpHeader.srcPort = htons(srcPort);*(unsigned short *)tcpHeader.dstPort = htons(80);*(unsigned int *)tcpHeader.seqNumber = htonl(0x00);*(unsigned int *)tcpHeader.ackNumber = htonl(0x00);tcpHeader.headLen = 5 << 4; tcpHeader.contrl = 1 << 1;*(unsigned short *)tcpHeader.wndSize = htons(0xFFFF);PSDTCP_HEADER psdHeader;memset(&psdHeader, 0, sizeof psdHeader);*(unsigned int *)psdHeader.dstIpAddr = inet_addr(lpszSrcIp);*(unsigned int *)psdHeader.srcIpAddr = inet_addr(lpszDstIp);psdHeader.protocol = 0x06;*(unsigned short *)psdHeader.tcpLen = htons(sizeof(TCP_HEADER));byte psdPacket[1024];memset(psdPacket, 0, sizeof psdPacket);memcpy( psdPacket, &psdHeader, sizeof psdHeader );memcpy( psdPacket + sizeof psdHeader, &tcpHeader, sizeof tcpHeader );*(unsigned short *)tcpHeader.checkSum = CheckSum( (unsigned short*) psdPacket, sizeof psdHeader + sizeof tcpHeader );IP_HEADER ipHeader;memset( &ipHeader, 0, sizeof ipHeader );unsigned char versionAndLen = 0x04;versionAndLen <<= 4;versionAndLen |= sizeof ipHeader / 4; //版本 + 头长度ipHeader.versionAndHeader = versionAndLen;*(unsigned short *)ipHeader.totalLen = htons( sizeof(IP_HEADER) + sizeof(TCP_HEADER) ); ipHeader.ttl = 0xFF;ipHeader.hiProtovolType = 0x06;*(unsigned int *)(ipHeader.srcIpAddr) = inet_addr(lpszSrcIp);*(unsigned int *)(ipHeader.dstIpAddr) = inet_addr(lpszDstIp);*(unsigned short *)(ipHeader.headerCheckSum) = CheckSum( (unsigned short *)&ipHeader, sizeof ipHeader );ETHERNET_HEADER ethHeader;memset(ðHeader, 0, sizeof ethHeader);memcpy(ethHeader.dstMacAddr, dstMac, 6);memcpy(ethHeader.srcMacAddr, srcMac, 6);*(unsigned short *)ethHeader.ethernetType = htons(0x0800);byte packet[1024];memset(packet, 0, sizeof packet);memcpy(packet, ðHeader, sizeof ethHeader);memcpy(packet + sizeof ethHeader, &ipHeader, sizeof ipHeader);memcpy(packet + sizeof ethHeader + sizeof ipHeader, &tcpHeader, sizeof tcpHeader);int size = sizeof ethHeader + sizeof ipHeader + sizeof tcpHeader;pcap_sendpacket(handle, packet, size );printf("%-16s ------SYN-----> %-16s\n", lpszSrcIp, lpszDstIp );if ( NULL == handle ){printf("\nUnable to open the adapter. %s is not supported by WinPcap\n");return 0;}byte param[1024];memset(param, 0x00, sizeof param );memcpy(param, &srcPort, sizeof srcPort );memcpy(param + sizeof srcPort, handle, 512 );pcap_loop( handle, -1, HandlePacketCallBack, param );pcap_close(handle);return 0;}

main函数先发起连接请求，即就是三次握手的第一步，然后开始抓包，如果抓到服务器回过来的SYN + ACK包，就表明服务器完成了第二次握手，接着向服务器再次发送ACK即就是第三次握手数据包，这样便建立了连接，然后可以向服务器发送HTTP请求，等待服务器回应。将适配器句柄和本地端口作为参数传给回调函数，用来发包和过滤。

void HandlePacketCallBack(unsigned char *param,const struct pcap_pkthdr* packet_header, const unsigned char *recvPacket){unsigned short localPort = *(unsigned short *)param;ETHERNET_HEADER *pEthHeader = ( ETHERNET_HEADER *)recvPacket;if ( *((unsigned short *)(pEthHeader->ethernetType)) != htons(0x0800) ) return;IP_HEADER *pIpHeader = ( IP_HEADER *)(recvPacket + sizeof(ETHERNET_HEADER) );if ( pIpHeader->hiProtovolType != 0x06 ) return;TCP_HEADER *pTcpHeader = ( TCP_HEADER *)(recvPacket + sizeof(ETHERNET_HEADER) + sizeof(IP_HEADER) );if ( *(unsigned short *)(pTcpHeader->dstPort) != htons(localPort) ) return ;//////////////////////////////////////////////////////////////////////IP_HEADER ipHeader;memset( &ipHeader, 0, sizeof ipHeader );unsigned char versionAndLen = 0x04;versionAndLen <<= 4;versionAndLen |= sizeof ipHeader / 4; //版本 + 头长度ipHeader.versionAndHeader = versionAndLen;*(unsigned short *)ipHeader.totalLen = htons( sizeof(IP_HEADER) + sizeof(TCP_HEADER) ); ipHeader.ttl = 0xFF;ipHeader.hiProtovolType = 0x06;memcpy(ipHeader.srcIpAddr, pIpHeader->dstIpAddr, sizeof(unsigned int) );memcpy(ipHeader.dstIpAddr, pIpHeader->srcIpAddr, sizeof(unsigned int) );*(unsigned short *)(ipHeader.headerCheckSum) = CheckSum( (unsigned short *)&ipHeader, sizeof ipHeader );////////////////////////////////////////////////////////////////////unsigned int ack = ntohl(*(unsigned int *)(pTcpHeader->seqNumber));unsigned int seq =  ntohl(*(unsigned int *)(pTcpHeader->ackNumber));TCP_HEADER tcpHeader;memset(&tcpHeader, 0, sizeof tcpHeader );*(unsigned short *)tcpHeader.srcPort = htons(localPort);*(unsigned short *)tcpHeader.dstPort = htons(80);*(unsigned int *)tcpHeader.seqNumber = htonl(seq);*(unsigned int *)tcpHeader.ackNumber = htonl(ack + 1);tcpHeader.headLen = 5 << 4; tcpHeader.contrl = 0x01 << 4; //*(unsigned short *)tcpHeader.wndSize = htons(0xFFFF);///////////////////////////////////////////////////////////////////PSDTCP_HEADER psdHeader;memset(&psdHeader, 0x00, sizeof psdHeader);psdHeader.protocol = 0x06;*(unsigned short *)psdHeader.tcpLen = htons(sizeof(TCP_HEADER));memcpy(psdHeader.dstIpAddr, ipHeader.dstIpAddr, sizeof(unsigned int) );memcpy(psdHeader.srcIpAddr, ipHeader.srcIpAddr, sizeof(unsigned int) );byte psdPacket[1024];memcpy( psdPacket, &psdHeader, sizeof psdHeader );memcpy( psdPacket + sizeof psdHeader, &tcpHeader, sizeof tcpHeader );*(unsigned short *)tcpHeader.checkSum = CheckSum( (unsigned short*) psdPacket, sizeof psdHeader + sizeof tcpHeader );ETHERNET_HEADER ethHeader;memset(ðHeader, 0, sizeof ethHeader);memcpy(ethHeader.dstMacAddr, pEthHeader->srcMacAddr, 6);memcpy(ethHeader.srcMacAddr, pEthHeader->dstMacAddr, 6);*(unsigned short *)ethHeader.ethernetType = htons(0x0800);byte packet[1024];memset(packet, 0, sizeof packet);memcpy(packet, ðHeader, sizeof ethHeader);memcpy(packet + sizeof ethHeader, &ipHeader, sizeof ipHeader);memcpy(packet + sizeof ethHeader + sizeof ipHeader, &tcpHeader, sizeof tcpHeader);int size = sizeof ethHeader + sizeof ipHeader + sizeof tcpHeader;pcap_t *handle = (pcap_t*)(param + sizeof(unsigned short));byte data[] = "GET / HTTP/1.1\r\n\r\n";char srcIp[32], dstIp[32];byte ctrl = pTcpHeader->contrl & 0x3F;switch ( ctrl ){case 0x01 << 1: //synbreak;/*case 0x01 << 4: //ackputs("收到ack");break;*/case ((0x01 << 4) | (0x01 << 1)): //syn+ackFormatIpAddr(*(unsigned int *)(pIpHeader->srcIpAddr), srcIp );FormatIpAddr(*(unsigned int *)(pIpHeader->dstIpAddr), dstIp );printf("%-16s ---SYN + ACK--> %-16s\n", srcIp, dstIp );///////////////////////////////////////////////////////////pcap_sendpacket(handle, packet, size );FormatIpAddr(*(unsigned int *)ipHeader.srcIpAddr, srcIp );FormatIpAddr(*(unsigned int *)ipHeader.dstIpAddr, dstIp );printf("%-16s ------ACK-----> %-16s\n", srcIp, dstIp );Sleep(10);pIpHeader = (IP_HEADER *)(packet + sizeof(ETHERNET_HEADER) );*(unsigned short *)(pIpHeader->totalLen) = htons(sizeof(IP_HEADER) + sizeof(TCP_HEADER) + sizeof data );memset(pIpHeader->headerCheckSum, 0x00, sizeof(unsigned short) );*(unsigned short *)(pIpHeader->headerCheckSum) = CheckSum( (unsigned short *)pIpHeader, sizeof(IP_HEADER) );pTcpHeader = (TCP_HEADER *)(packet + sizeof(ETHERNET_HEADER) + sizeof(IP_HEADER));pTcpHeader->contrl = 0x01 << 4;*(unsigned int *)(pTcpHeader->ackNumber) = htonl(ack+1);*(unsigned int *)(pTcpHeader->seqNumber) = htonl(seq);memset( pTcpHeader->checkSum, 0x00, sizeof(unsigned short) );memset( psdPacket, 0x00, sizeof psdPacket );*(unsigned short *)psdHeader.tcpLen = htons(sizeof(TCP_HEADER) + sizeof(data));memcpy( psdPacket, &psdHeader, sizeof psdHeader );memcpy( psdPacket + sizeof psdHeader, pTcpHeader, sizeof(TCP_HEADER) );memcpy( psdPacket + sizeof psdHeader + sizeof(TCP_HEADER), data, sizeof data );*(unsigned short *)(pTcpHeader->checkSum) = CheckSum( (unsigned short*) psdPacket, sizeof psdHeader + sizeof(TCP_HEADER) + sizeof data );memcpy(packet, ðHeader, sizeof ethHeader);memcpy(packet + sizeof(ETHERNET_HEADER), pIpHeader, sizeof(IP_HEADER) );memcpy(packet + sizeof(ETHERNET_HEADER) + sizeof(IP_HEADER), pTcpHeader, sizeof(TCP_HEADER) );memcpy(packet + sizeof(ETHERNET_HEADER) + sizeof(IP_HEADER)+ sizeof(TCP_HEADER), data, sizeof data );size += sizeof data;pcap_sendpacket(handle, packet, size );break;default:IP_HEADER *pIpHeader = (IP_HEADER *)(recvPacket + sizeof(ETHERNET_HEADER) );unsigned short ipHeaderLen = pIpHeader->versionAndHeader & 0x0F;ipHeaderLen *= 4;TCP_HEADER *pTcpHeader = (TCP_HEADER *)(recvPacket + sizeof(ETHERNET_HEADER)  + ipHeaderLen );int tcpHeaderLen = pTcpHeader->headLen >> 0x04;tcpHeaderLen *= 4;char *str = ( char *)(recvPacket + sizeof(ETHERNET_HEADER) + ipHeaderLen + tcpHeaderLen );puts(str);}return;}

回调函数首先过滤掉非IP数据包，再过滤掉非TCP数据包，再根据端口过滤掉不是自己的TCP数据包。值得注意的就是组包时的包长度和校验和，我就在这个地方耗了很久。

在解析包的时候最好不要直接用sizeof(IP_HEADER)这样类似的写法，而是直接读取报头中的报头长度字段，这样会更精确些，因为我们不用知道服务器有没有添加选项数据。

最后的结果：

最后贴上全部源码

#include <stdio.h>#include <stdlib.h>#include <pcap.h>#include <winsock2.h>#include <iostream>using namespace std;#pragma comment(lib, "../common/lib/Packet.lib")#pragma comment(lib, "../common/lib/wpcap.lib")#pragma comment(lib, "ws2_32.lib")/*                       IP报文格式0            8           16                        32+------------+------------+-------------------------+| ver + hlen |  服务类型  |         总长度          |+------------+------------+----+--------------------+|           标识位        |flag|   分片偏移(13位)   |+------------+------------+----+--------------------+|  生存时间  | 高层协议号 |       首部校验和        |+------------+------------+-------------------------+|                   源 IP 地址                      |+---------------------------------------------------+|                  目的 IP 地址                     |+---------------------------------------------------+*/struct IP_HEADER{byte versionAndHeader;byte serviceType;byte totalLen[2];byte seqNumber[2];byte flagAndFragPart[2];byte ttl;byte hiProtovolType;byte headerCheckSum[2];byte srcIpAddr[4];byte dstIpAddr[4];};/*                     TCP 报文0                       16                       32+------------------------+-------------------------+|      源端口地址        |      目的端口地址       |+------------------------+-------------------------+|                      序列号                      |+--------------------------------------------------+|                      确认号                      |+------+--------+--------+-------------------------+|HLEN/4| 保留位 |控制位/6|         窗口尺寸        |+------+--------+--------+-------------------------+|         校验和         |         应急指针        |+------------------------+-------------------------+*/struct TCP_HEADER{byte srcPort[2];byte dstPort[2];byte seqNumber[4];byte ackNumber[4];byte headLen;byte contrl;byte wndSize[2];byte checkSum[2];byte uragentPtr[2];};struct PSDTCP_HEADER{ byte srcIpAddr[4];     //Source IP address; 32 bitsbyte dstIpAddr[4];     //Destination IP address; 32 bits byte padding;          //paddingbyte protocol;         //Protocol; 8 bitsbyte tcpLen[2];        //TCP length; 16 bits} ;struct ETHERNET_HEADER{  byte dstMacAddr[6];byte srcMacAddr[6];byte ethernetType[2];};char *FormatIpAddr( unsigned uIpAddr, char szIp[] ){IN_ADDR addr;addr.S_un.S_addr = uIpAddr;strcpy( szIp, inet_ntoa( addr ) );return szIp;}unsigned short CheckSum(unsigned short packet[], int size ){unsigned long cksum = 0;while (size > 1) {cksum += *packet++;size -= sizeof(USHORT);}if (size) {cksum += *(UCHAR*)packet;}cksum = (cksum >> 16) + (cksum & 0xffff);cksum += (cksum >>16);return (USHORT)(~cksum);}void HandlePacketCallBack(unsigned char *param,const struct pcap_pkthdr* packet_header, const unsigned char *recvPacket){unsigned short localPort = *(unsigned short *)param;ETHERNET_HEADER *pEthHeader = ( ETHERNET_HEADER *)recvPacket;if ( *((unsigned short *)(pEthHeader->ethernetType)) != htons(0x0800) ) return;IP_HEADER *pIpHeader = ( IP_HEADER *)(recvPacket + sizeof(ETHERNET_HEADER) );if ( pIpHeader->hiProtovolType != 0x06 ) return;TCP_HEADER *pTcpHeader = ( TCP_HEADER *)(recvPacket + sizeof(ETHERNET_HEADER) + sizeof(IP_HEADER) );if ( *(unsigned short *)(pTcpHeader->dstPort) != htons(localPort) ) return ;//////////////////////////////////////////////////////////////////////IP_HEADER ipHeader;memset( &ipHeader, 0, sizeof ipHeader );unsigned char versionAndLen = 0x04;versionAndLen <<= 4;versionAndLen |= sizeof ipHeader / 4; //版本 + 头长度ipHeader.versionAndHeader = versionAndLen;*(unsigned short *)ipHeader.totalLen = htons( sizeof(IP_HEADER) + sizeof(TCP_HEADER) ); ipHeader.ttl = 0xFF;ipHeader.hiProtovolType = 0x06;memcpy(ipHeader.srcIpAddr, pIpHeader->dstIpAddr, sizeof(unsigned int) );memcpy(ipHeader.dstIpAddr, pIpHeader->srcIpAddr, sizeof(unsigned int) );*(unsigned short *)(ipHeader.headerCheckSum) = CheckSum( (unsigned short *)&ipHeader, sizeof ipHeader );////////////////////////////////////////////////////////////////////unsigned int ack = ntohl(*(unsigned int *)(pTcpHeader->seqNumber));unsigned int seq =  ntohl(*(unsigned int *)(pTcpHeader->ackNumber));TCP_HEADER tcpHeader;memset(&tcpHeader, 0, sizeof tcpHeader );*(unsigned short *)tcpHeader.srcPort = htons(localPort);*(unsigned short *)tcpHeader.dstPort = htons(80);*(unsigned int *)tcpHeader.seqNumber = htonl(seq);*(unsigned int *)tcpHeader.ackNumber = htonl(ack + 1);tcpHeader.headLen = 5 << 4; tcpHeader.contrl = 0x01 << 4; //*(unsigned short *)tcpHeader.wndSize = htons(0xFFFF);///////////////////////////////////////////////////////////////////PSDTCP_HEADER psdHeader;memset(&psdHeader, 0x00, sizeof psdHeader);psdHeader.protocol = 0x06;*(unsigned short *)psdHeader.tcpLen = htons(sizeof(TCP_HEADER));memcpy(psdHeader.dstIpAddr, ipHeader.dstIpAddr, sizeof(unsigned int) );memcpy(psdHeader.srcIpAddr, ipHeader.srcIpAddr, sizeof(unsigned int) );byte psdPacket[1024];memcpy( psdPacket, &psdHeader, sizeof psdHeader );memcpy( psdPacket + sizeof psdHeader, &tcpHeader, sizeof tcpHeader );*(unsigned short *)tcpHeader.checkSum = CheckSum( (unsigned short*) psdPacket, sizeof psdHeader + sizeof tcpHeader );ETHERNET_HEADER ethHeader;memset(ðHeader, 0, sizeof ethHeader);memcpy(ethHeader.dstMacAddr, pEthHeader->srcMacAddr, 6);memcpy(ethHeader.srcMacAddr, pEthHeader->dstMacAddr, 6);*(unsigned short *)ethHeader.ethernetType = htons(0x0800);byte packet[1024];memset(packet, 0, sizeof packet);memcpy(packet, ðHeader, sizeof ethHeader);memcpy(packet + sizeof ethHeader, &ipHeader, sizeof ipHeader);memcpy(packet + sizeof ethHeader + sizeof ipHeader, &tcpHeader, sizeof tcpHeader);int size = sizeof ethHeader + sizeof ipHeader + sizeof tcpHeader;pcap_t *handle = (pcap_t*)(param + sizeof(unsigned short));byte data[] = "GET / HTTP/1.1\r\n\r\n";char srcIp[32], dstIp[32];byte ctrl = pTcpHeader->contrl & 0x3F;switch ( ctrl ){case 0x01 << 1: //synbreak;/*case 0x01 << 4: //ackputs("收到ack");break;*/case ((0x01 << 4) | (0x01 << 1)): //syn+ackFormatIpAddr(*(unsigned int *)(pIpHeader->srcIpAddr), srcIp );FormatIpAddr(*(unsigned int *)(pIpHeader->dstIpAddr), dstIp );printf("%-16s ---SYN + ACK--> %-16s\n", srcIp, dstIp );///////////////////////////////////////////////////////////pcap_sendpacket(handle, packet, size );FormatIpAddr(*(unsigned int *)ipHeader.srcIpAddr, srcIp );FormatIpAddr(*(unsigned int *)ipHeader.dstIpAddr, dstIp );printf("%-16s ------ACK-----> %-16s\n", srcIp, dstIp );Sleep(10);pIpHeader = (IP_HEADER *)(packet + sizeof(ETHERNET_HEADER) );*(unsigned short *)(pIpHeader->totalLen) = htons(sizeof(IP_HEADER) + sizeof(TCP_HEADER) + sizeof data );memset(pIpHeader->headerCheckSum, 0x00, sizeof(unsigned short) );*(unsigned short *)(pIpHeader->headerCheckSum) = CheckSum( (unsigned short *)pIpHeader, sizeof(IP_HEADER) );pTcpHeader = (TCP_HEADER *)(packet + sizeof(ETHERNET_HEADER) + sizeof(IP_HEADER));pTcpHeader->contrl = 0x01 << 4;*(unsigned int *)(pTcpHeader->ackNumber) = htonl(ack+1);*(unsigned int *)(pTcpHeader->seqNumber) = htonl(seq);memset( pTcpHeader->checkSum, 0x00, sizeof(unsigned short) );memset( psdPacket, 0x00, sizeof psdPacket );*(unsigned short *)psdHeader.tcpLen = htons(sizeof(TCP_HEADER) + sizeof(data));memcpy( psdPacket, &psdHeader, sizeof psdHeader );memcpy( psdPacket + sizeof psdHeader, pTcpHeader, sizeof(TCP_HEADER) );memcpy( psdPacket + sizeof psdHeader + sizeof(TCP_HEADER), data, sizeof data );*(unsigned short *)(pTcpHeader->checkSum) = CheckSum( (unsigned short*) psdPacket, sizeof psdHeader + sizeof(TCP_HEADER) + sizeof data );memcpy(packet, ðHeader, sizeof ethHeader);memcpy(packet + sizeof(ETHERNET_HEADER), pIpHeader, sizeof(IP_HEADER) );memcpy(packet + sizeof(ETHERNET_HEADER) + sizeof(IP_HEADER), pTcpHeader, sizeof(TCP_HEADER) );memcpy(packet + sizeof(ETHERNET_HEADER) + sizeof(IP_HEADER)+ sizeof(TCP_HEADER), data, sizeof data );size += sizeof data;pcap_sendpacket(handle, packet, size );break;default:IP_HEADER *pIpHeader = (IP_HEADER *)(recvPacket + sizeof(ETHERNET_HEADER) );unsigned short ipHeaderLen = pIpHeader->versionAndHeader & 0x0F;ipHeaderLen *= 4;TCP_HEADER *pTcpHeader = (TCP_HEADER *)(recvPacket + sizeof(ETHERNET_HEADER)  + ipHeaderLen );int tcpHeaderLen = pTcpHeader->headLen >> 0x04;tcpHeaderLen *= 4;char *str = ( char *)(recvPacket + sizeof(ETHERNET_HEADER) + ipHeaderLen + tcpHeaderLen );puts(str);}return;}int main(){srand(time(0));unsigned short srcPort = rand()%65535;//6382;const char *lpszSrcIp = "10.126.72.37";const char *lpszDstIp = "112.80.248.73";const byte srcMac[] = {0x90, 0x2B, 0x34, 0x9A, 0xC2, 0xBB};//主机macconst byte dstMac[] = {0x00, 0x00, 0x5e, 0x00, 0x01, 0x48}; //网关macchar szError[1024];const char *lpszAdapterName = "\\Device\\NPF_{1DDB19E0-EC33-46E2-ACB5-085E87EF6489}";pcap_t *handle = pcap_open_live(lpszAdapterName, 65536, 1, 1000, szError );if ( NULL == handle ) return 0;TCP_HEADER tcpHeader;memset(&tcpHeader, 0, sizeof tcpHeader );*(unsigned short *)tcpHeader.srcPort = htons(srcPort);*(unsigned short *)tcpHeader.dstPort = htons(80);*(unsigned int *)tcpHeader.seqNumber = htonl(0x00);*(unsigned int *)tcpHeader.ackNumber = htonl(0x00);tcpHeader.headLen = 5 << 4; tcpHeader.contrl = 1 << 1;*(unsigned short *)tcpHeader.wndSize = htons(0xFFFF);PSDTCP_HEADER psdHeader;memset(&psdHeader, 0, sizeof psdHeader);*(unsigned int *)psdHeader.dstIpAddr = inet_addr(lpszSrcIp);*(unsigned int *)psdHeader.srcIpAddr = inet_addr(lpszDstIp);psdHeader.protocol = 0x06;*(unsigned short *)psdHeader.tcpLen = htons(sizeof(TCP_HEADER));byte psdPacket[1024];memset(psdPacket, 0, sizeof psdPacket);memcpy( psdPacket, &psdHeader, sizeof psdHeader );memcpy( psdPacket + sizeof psdHeader, &tcpHeader, sizeof tcpHeader );*(unsigned short *)tcpHeader.checkSum = CheckSum( (unsigned short*) psdPacket, sizeof psdHeader + sizeof tcpHeader );IP_HEADER ipHeader;memset( &ipHeader, 0, sizeof ipHeader );unsigned char versionAndLen = 0x04;versionAndLen <<= 4;versionAndLen |= sizeof ipHeader / 4; //版本 + 头长度ipHeader.versionAndHeader = versionAndLen;*(unsigned short *)ipHeader.totalLen = htons( sizeof(IP_HEADER) + sizeof(TCP_HEADER) ); ipHeader.ttl = 0xFF;ipHeader.hiProtovolType = 0x06;*(unsigned int *)(ipHeader.srcIpAddr) = inet_addr(lpszSrcIp);*(unsigned int *)(ipHeader.dstIpAddr) = inet_addr(lpszDstIp);*(unsigned short *)(ipHeader.headerCheckSum) = CheckSum( (unsigned short *)&ipHeader, sizeof ipHeader );ETHERNET_HEADER ethHeader;memset(ðHeader, 0, sizeof ethHeader);memcpy(ethHeader.dstMacAddr, dstMac, 6);memcpy(ethHeader.srcMacAddr, srcMac, 6);*(unsigned short *)ethHeader.ethernetType = htons(0x0800);byte packet[1024];memset(packet, 0, sizeof packet);memcpy(packet, ðHeader, sizeof ethHeader);memcpy(packet + sizeof ethHeader, &ipHeader, sizeof ipHeader);memcpy(packet + sizeof ethHeader + sizeof ipHeader, &tcpHeader, sizeof tcpHeader);int size = sizeof ethHeader + sizeof ipHeader + sizeof tcpHeader;pcap_sendpacket(handle, packet, size );printf("%-16s ------SYN-----> %-16s\n", lpszSrcIp, lpszDstIp );if ( NULL == handle ){printf("\nUnable to open the adapter. %s is not supported by WinPcap\n");return 0;}byte param[1024];memset(param, 0x00, sizeof param );memcpy(param, &srcPort, sizeof srcPort );memcpy(param + sizeof srcPort, handle, 512 );pcap_loop( handle, -1, HandlePacketCallBack, param );pcap_close(handle);return 0;}