Window下c++原始套接字来截包

最近要交这个作业，紧赶慢赶写出来了，不过写出来后有时候好用有时候不好用，真是醉了，原来是获取本地IP地址时候多块网卡，有时候IP就获取错了，所以运行时最好先看看是哪块网卡，对应的IP对不对。

// WinSocketRaw.cpp : 定义控制台应用程序的入口点。
//

#include <iostream>
#include "winsock2.h"


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

using namespace std;

struct IP //定义IP首部

{
    unsigned char h_lenver; //4位首部长度+4位IP版本号
    unsigned char tos; //8位服务类型TOS
    unsigned short total_len; //16位总长度（字节）
    unsigned short ident; //16位标识
    unsigned short frag_and_flags; //3位标志位
    unsigned char ttl; //8位生存时间 TTL
    unsigned char proto; //8位协议 (TCP, UDP 或其他)
    unsigned short checksum; //16位IP首部校验和
    unsigned int sourceIP; //32位源IP地址
    unsigned int destIP; //32位目的IP地址
};

struct TCP//定义TCP首部
{
    unsigned short source_port; //16
    unsigned short dest_port;
    unsigned sequence;   //32
    unsigned ack;
    unsigned char lenres;   //8
    unsigned char flag;
    unsigned short win;   //16
    unsigned short sum;
    unsigned short urp;
};

struct UDP//定义UDP首部
{
    unsigned short sport;//16位源端口
    unsigned short dport;//16位目的端口
    unsigned short len;//UDP 长度
    unsigned short cksum;//检查和
};

/*不处理ICMP数据 struct ICMP//定义ICMP首部 { unsigned short sport; unsigned short dport; unsigned char type; unsigned char code; unsigned short cksum; unsigned short id; unsigned short seq; unsigned long timestamp; };*/

int main()
{
    SOCKET sock;
    WSADATA wsd;
    char recvInf[65535] = { 0 }; //收到的信息
    DWORD dwBytesRet;

    int pCount = 0; //收到的包数量
    unsigned int optval = 1; //参数值
    char * ip = NULL; //对ip数据的指针
    char * tcp = NULL; //对tcp数据的指针
    char * udp = NULL; //对udp数据的指针
    int lentcp, lenudp;

    WSAStartup(MAKEWORD(2, 1), &wsd);

    if ((sock = socket(AF_INET, SOCK_RAW, IPPROTO_IP)) == SOCKET_ERROR)
    {
        cout << "启动原始嵌套字出错!" << endl;
        exit(-1);
    }


    //获取本机地址
    char  name[MAXBYTE];
    gethostname(name, MAXBYTE);
    cout << name << endl;
    struct hostent FAR * pHostent;
    pHostent = (struct hostent *)malloc(sizeof(struct hostent));
    pHostent = gethostbyname(name);


    //设置
    SOCKADDR_IN sa;
    sa.sin_family = AF_INET;
    sa.sin_addr.s_addr = INADDR_ANY;

    //就是这！
    memcpy(&sa.sin_addr, pHostent->h_addr_list[2], pHostent->h_length); //设置本机地址*/
cout << inet_ntoa(*((struct in_addr*)pHostent->h_addr_list[2])) << endl;//看下IP地址

    if (SOCKET_ERROR == bind(sock, (SOCKADDR *)&sa, sizeof(sa)))
    {
        cout << "绑定出错！" << endl;
        exit(-2);
    }

    //将网卡设置为混杂模式
    if(SOCKET_ERROR == WSAIoctl(sock, (IOC_IN|IOC_VENDOR|1), &optval, sizeof(optval), nullptr, 0, &dwBytesRet, nullptr, nullptr))
    {
        cout << "混杂失败！" << endl;
    }

    IP * pip = NULL;//IP数据块指针
    TCP * ptcp = NULL;//TCP数据块指针
    UDP * pudp = NULL;//UDP数据块指针
    char szSourceIP[32];//源IP
    char szDestIP[32];//目的IP
    SOCKADDR_IN saSource;//源地址结构体
    SOCKADDR_IN saDest;//目的地址结构体
    int lenfrom = sizeof(saSource);
    pip = (IP*)recvInf;

    while (true)
    {
        recv(sock, recvInf, sizeof(recvInf), 0);//接收包
        //将32位IP地址转为数字 .形式

        //只处理TCP UDP信息包
        if (!(pip->proto == IPPROTO_TCP || pip->proto == IPPROTO_UDP))
            continue;

        pCount++;
        saSource.sin_addr.s_addr = pip->sourceIP;
        strncpy(szSourceIP, inet_ntoa(saSource.sin_addr), 32);
        saDest.sin_addr.s_addr = pip->destIP;
        strncpy(szDestIP, inet_ntoa(saDest.sin_addr), 32);

        lentcp = ntohs(pip->total_len) - (sizeof(IP) + sizeof(TCP));
        lenudp = ntohs(pip->total_len) - (sizeof(IP) + sizeof(UDP));

        system("cls");
        cout << "################第"<< pCount <<  " 号包#######################" << endl;
        cout << "****************** IP头部信息 *********************" << endl;
        cout << "源IP: " << szSourceIP << endl << "目的IP:" << szDestIP << endl;

        //处理TCP包
        if (pip->proto == IPPROTO_TCP && lentcp != 0)
        {
            ptcp = (TCP *)(recvInf + sizeof(IP));
            char * data = recvInf + sizeof(IP) + sizeof(TCP); //TCP数据指针
            cout << "************** TCP头部信息 ********************" << endl;
            cout << "源端口号:" << ptcp->source_port << endl << "目的端口号：" << ptcp->dest_port << endl;
            cout << "数据：" << data << endl;
        }

        //处理UDP包
        if (pip->proto == IPPROTO_UDP && lenudp != 0)
        {
            pudp = (UDP *)(recvInf + sizeof(IP));
            char * data = recvInf + sizeof(IP) + sizeof(UDP); //UDP数据指针
            cout << "************** UDP头部信息 ********************" << endl;
            cout << "源端口号:" << pudp->sport << endl << "目的端口号：" << pudp->dport << endl;
            cout << "数据：" << data << endl;
        }

        memset(recvInf, 0, sizeof(recvInf));//清空缓冲区
    }
}