C++ 原始套接字读取同一数据包两次

我的目标是读取发送到特定类型IP地址的所有数据包，这些数据包满足条件

isIpInRange（）

这是我正在使用的代码。

scannerThread

中的代码实现了我上面所说的功能。主线程中的代码用于与nodejs web应用程序建立另一个TCP连接，我应该将捕获的实际数据包发送到该应用程序（从IP头和上面）

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使用名称空间std；
国际标准差饷物业估价署；
字符串getIP（无符号整数IP）
{
无符号字符*p=（无符号字符*）&IP；
返回到_字符串（p[0]）+“+”+到_字符串（p[1]）+“+”+到_字符串（p[2]）+“+”+到_字符串（p[3]）；
}
无效打印（ip I）
{
库特
#include <bits/stdc++.h>
#include <sys/socket.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <fcntl.h>
#include <linux/tcp.h>
#include <net/if.h>
#include <linux/if_packet.h>
#include <net/ethernet.h>

using namespace std;

int rsfd, sfd;

string getIP(unsigned int IP)
{
    unsigned char *p = (unsigned char *)&IP;
    return to_string(p[0]) + "." + to_string(p[1]) + "." + to_string(p[2]) + "." + to_string(p[3]);
}

void print(ip I)
{
    cout << "Version: " << (int)I.ip_v << endl;
    cout << "Header Length: " << (int)I.ip_hl << endl;
    cout << "Type of Service: " << (int)I.ip_tos << endl;
    cout << "Packet Length: " << ntohs((int)I.ip_len) << endl;
    cout << "ID: " << ntohs((int)I.ip_id) << endl;
    cout << "Fragment: " << ntohs((int)I.ip_off) << endl;
    cout << "Time to Live: " << (int)I.ip_ttl << endl;
    cout << "Higher Level Protocol: " << (int)I.ip_p << endl;
    cout << "CheckSum: " << ntohs((int)I.ip_sum) << endl;
    cout << "Sender: " << getIP(I.ip_src.s_addr) << endl;
    cout << "Receiver: " << getIP(I.ip_dst.s_addr) << endl;
}

bool isIpInRange(in_addr_t ipaddr)
{
    uint8_t *p = (uint8_t *)&ipaddr;
    return p[0] == 127 && p[1] == 200;
}

void *scanner(void *arg)
{
    rsfd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
    if (sfd < 0)
    {
        perror("RAW socket");
        exit(1);
    }

    sockaddr_ll addr;
    memset(&addr, 0, sizeof(addr));
    if ((addr.sll_ifindex = if_nametoindex("lo")) == 0)
    {
        perror("if_nametoindex() failed to obtain interface index ");
        exit(EXIT_FAILURE);
    }
    addr.sll_protocol = htons(ETH_P_ALL);
    addr.sll_family = AF_PACKET;

    bind(rsfd, (sockaddr *)&addr, sizeof(addr));

    char buffer[1024];
    char *buf;

    int bytes;

    while (1)
    {
        bytes = recvfrom(rsfd, buffer, 1024, 0, NULL, NULL);
        buffer[bytes] = 0;

        buf = buffer + 14;
        ip *I = (ip *)buf;
        if (!isIpInRange(I->ip_dst.s_addr))
            // if (I->ip_dst.s_addr != 16828543)
            continue;

        print(*I);
        if (I->ip_p == 17)
            cout << buf + 28 << endl;
        else if (I->ip_p == 6)
            cout << buf + 40 << endl;
        // send(sfd, buf, bytes - 14, 0);
        cout<<endl;
    }
}

int main()
{
    sfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sfd < 0)
    {
        perror("TCP socket");
        exit(1);
    }
    sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    addr.sin_port = htons(12000);

    if (connect(sfd, (sockaddr *)&addr, sizeof(sockaddr_in)) < 0)
    {
        perror("connect");
        exit(1);
    }

    pthread_t scannerThread;
    pthread_create(&scannerThread, NULL, scanner, NULL);

    int bytes;
    char buffer[1024];
    char *buf;

    while (1)
    {
        bytes = recv(sfd, buffer, 1024, 0);
        buffer[bytes] = 0;

        cout << bytes << " bytes received from outside" << endl;
    }

    pthread_join(scannerThread, NULL);
}

#include <bits/stdc++.h>
#include <sys/socket.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <fcntl.h>

using namespace std;

int main(int argc, char *argv[])
{
    int sfd = socket(AF_INET, SOCK_DGRAM, 0);
    sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = inet_addr("127.200.0.1");
    addr.sin_port = htons(10000);

    char buffer[1024] = "KILL";
    int bytes;

    sendto(sfd, buffer, 5, 0, (sockaddr *)&addr, sizeof(addr));

}