// pcap_next 接收下一条数据
#include <pcap.h> // libpcap头文件
#include <stdio.h>
#include <netinet/in.h>
#include <netinet/ether.h>
#include <netinet/ip.h>
#include <arpa/inet.h> // 网络地址转换函数,如inet_ntoa()->将网络地址转换成“.”点隔的字符串格式
#include <string.h>
#include <unistd.h>

int main(int argc, char const *argv[])
{
    // 1. 获取可用的网络设备名称
    char *dev = pcap_lookupdev(NULL); // NULL表示获取默认网络设备
    if (dev != NULL)
    {
        printf("网络设备名称: %s\n", dev);
    }

    // 2. 打开网络设备, 开始捕获数据
    char err_buf[PCAP_ERRBUF_SIZE] = "";
    pcap_t *cap = pcap_open_live(dev, 128, 0, 0, err_buf);
    if (cap == NULL)
    {
        printf("open pcap fail: %s\n", err_buf);
        return -1;
    }

    // 3. 开始捕获数据
    while (1)
    {
        struct pcap_pkthdr cap_hdr;
        bzero(&cap_hdr, sizeof(cap_hdr));
        const u_char *data = pcap_next(cap, &cap_hdr);
        if (cap_hdr.len > 0)
        {
            printf("数据包长度: %d, 实际长度: %d\n", cap_hdr.caplen, cap_hdr.len);
        }

        // 分析 mac 报文的数据
        struct ether_header *mac_hdr = (struct ether_header *)data;
        unsigned char src_mac[18] = "";
        unsigned char dst_mac[18] = "";

        sprintf(dst_mac, "%02x:%02x:%02x:%02x:%02x:%02x",
                mac_hdr->ether_dhost[0],
                mac_hdr->ether_dhost[1],
                mac_hdr->ether_dhost[2],
                mac_hdr->ether_dhost[3],
                mac_hdr->ether_dhost[4],
                mac_hdr->ether_dhost[5]);

        sprintf(src_mac, "%02x:%02x:%02x:%02x:%02x:%02x",
                mac_hdr->ether_shost[0],
                mac_hdr->ether_shost[1],
                mac_hdr->ether_dhost[2],
                mac_hdr->ether_shost[3],
                mac_hdr->ether_shost[4],
                mac_hdr->ether_shost[5]);

        unsigned short mac_type = ntohs(mac_hdr->ether_type);

        printf("type(%#x) src mac: %s, dst mac: %s\n", mac_type, src_mac, dst_mac);
        if (mac_type == 0x0800)
        {
            // 分析 ip 报文的数据
            struct iphdr *ip_hdr = (struct iphdr *)(data + sizeof(struct ether_header));
            u_char src_ip[INET_ADDRSTRLEN] = "";
            u_char dst_ip[INET_ADDRSTRLEN] = "";
            inet_ntop(AF_INET, &ip_hdr->saddr, src_ip, INET_ADDRSTRLEN);
            inet_ntop(AF_INET, &ip_hdr->daddr, dst_ip, INET_ADDRSTRLEN);

            printf("ip type(%d) %s->%s\n", ip_hdr->protocol, src_ip, dst_ip);
        }

        sleep(1);
    }

    // 关闭网卡设备
    pcap_close(cap);

    return 0;
}