给我一个基于bpf的linux 网络丢包监控的C++代码

以下是一个基于BPF的Linux网络丢包监控的C代码示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <linux/if_packet.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <linux/filter.h>
#include <errno.h>
#include <unistd.h>

#define BUFSIZE 2048

int main(int argc, char *argv[]) {
    int sock_fd;
    char buffer[BUFSIZE];
    struct sockaddr_ll saddr;
    int saddr_len = sizeof(saddr);
    struct sock_filter bpf_code[] = {
        /* Match all packets */
        { 0x6, 0, 0, 0x00000000 },
        { 0x6, 0, 0, 0x00000000 },
        { 0x6, 0, 0, 0x00000000 },
        { 0x6, 0, 0, 0x00000000 },
        { 0x6, 0, 0, 0x00000000 },
        { 0x6, 0, 0, 0x00000000 },
        { 0x6, 0, 0, 0x00000000 },
        { 0x6, 0, 0, 0x00000000 },
        { 0x6, 0, 0, 0x00000000 },
        { 0x6, 0, 0, 0x00000000 },
    };
    struct sock_fprog filter = {
        .len = sizeof(bpf_code) / sizeof(struct sock_filter),
        .filter = bpf_code,
    };

    if ((sock_fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL))) < 0) {
        perror("socket");
        exit(1);
    }

    /* Set the BPF filter */
    if (setsockopt(sock_fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) < 0) {
        perror("setsockopt");
        exit(1);
    }

    while (1) {
        int len = recvfrom(sock_fd, buffer, BUFSIZE, 0, (struct sockaddr *)&saddr, &saddr_len);
        if (len < 0) {
            perror("recvfrom");
            exit(1);
        }

        /* Check for dropped packets */
        if (saddr.sll_pkttype == PACKET_OUTGOING) {
            printf("Packet dropped!\n");
        }
    }

    close(sock_fd);
    return 0;
}

该代码创建一个原始套接字并使用BPF过滤器来捕获所有网络数据包。它在每次接收到数据包时检查包的类型，如果为“出包”则打印出“Packet dropped!”的消息。这样，您就可以使用此代码来监视Linux系统上的网络丢包情况。