c语言代码实现arp字段解析 详细代码

以下是使用C语言解析ARP协议包的详细代码：

#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <netinet/if_ether.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/in.h>
#include <net/ethernet.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

void arp_packet_parser(const u_char *packet) {
    struct ether_header *eth_header;
    eth_header = (struct ether_header *) packet;

    if (ntohs(eth_header->ether_type) == ETHERTYPE_ARP) {
        printf("\nARP Packet:\n");
        printf("Source MAC Address: %.2X:%.2X:%.2X:%.2X:%.2X:%.2X\n",
               eth_header->ether_shost[0], eth_header->ether_shost[1], eth_header->ether_shost[2],
               eth_header->ether_shost[3], eth_header->ether_shost[4], eth_header->ether_shost[5]);
        printf("Destination MAC Address: %.2X:%.2X:%.2X:%.2X:%.2X:%.2X\n",
               eth_header->ether_dhost[0], eth_header->ether_dhost[1], eth_header->ether_dhost[2],
               eth_header->ether_dhost[3], eth_header->ether_dhost[4], eth_header->ether_dhost[5]);

        packet += sizeof(struct ether_header);
        struct ether_arp *arp_header;
        arp_header = (struct ether_arp *) packet;

        printf("Sender MAC Address: %.2X:%.2X:%.2X:%.2X:%.2X:%.2X\n",
               arp_header->arp_sha[0], arp_header->arp_sha[1], arp_header->arp_sha[2],
               arp_header->arp_sha[3], arp_header->arp_sha[4], arp_header->arp_sha[5]);
        printf("Sender IP Address: %s\n", inet_ntoa(*(struct in_addr *) arp_header->arp_spa));
        printf("Target MAC Address: %.2X:%.2X:%.2X:%.2X:%.2X:%.2X\n",
               arp_header->arp_tha[0], arp_header->arp_tha[1], arp_header->arp_tha[2],
               arp_header->arp_tha[3], arp_header->arp_tha[4], arp_header->arp_tha[5]);
        printf("Target IP Address: %s\n", inet_ntoa(*(struct in_addr *) arp_header->arp_tpa));
    }
}

void packet_handler(u_char *args, const struct pcap_pkthdr *header, const u_char *packet) {
    arp_packet_parser(packet);
}

int main() {
    char errbuf[PCAP_ERRBUF_SIZE];
    pcap_t *handle;
    struct bpf_program fp;
    char filter_exp[] = "arp";
    bpf_u_int32 net;
    bpf_u_int32 mask;

    // 打开网络设备
    handle = pcap_open_live("eth0", BUFSIZ, 1, 1000, errbuf);

    // 获取网络设备的网段和掩码
    pcap_lookupnet("eth0", &net, &mask, errbuf);

    // 编译过滤规则
    pcap_compile(handle, &fp, filter_exp, 0, net);

    // 设置过滤规则
    pcap_setfilter(handle, &fp);

    // 开始抓包
    pcap_loop(handle, -1, packet_handler, NULL);

    // 关闭网络设备
    pcap_close(handle);

    return 0;
}

以上代码使用pcap库来抓取网络数据包，并使用`arp_packet_parser()`函数来解析ARP协议包。在解析ARP协议包时，我们首先需要获取以太网帧头部，并判断是否为ARP协议包，然后再获取ARP协议包头部，从中提取出需要的信息，如MAC地址和IP地址等。最后，我们可以将这些信息打印出来，以便于查看。