156 lines
5.1 KiB
C
156 lines
5.1 KiB
C
#include "net_task_thread.h"
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void *net_task(void *arg)
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{
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printf("net_task\n");
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char *dev1 = "ens33"; // 第一个网卡
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char *dev2 = "ens38"; // 第二个网卡
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// 打开网卡设备
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// libnet_context1 使用 open_device 函数打开网卡设备1 后返回的 libnet 上下文
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libnet_context1 = open_device(&device1, dev1);
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libnet_context2 = open_device(&device2, dev2);
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// 开始捕获数据包:
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// pcap_loop: 网卡设备、捕获的数据包个数、回调函数、传递给回调函数的参数
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pcap_loop(device1, -1, process_packet, NULL); // -1 表示无限循环
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pcap_loop(device2, -1, process_packet, NULL); // -1 表示无限循环
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return NULL;
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}
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// 打开网卡设备
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// 如果成功打开网卡设备，就返回 libnet 上下文
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libnet_t *open_device(pcap_t **device, char *dev_name)
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{
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// 打开网卡设备: 设备名、最大字节数、混杂模式、超时时间、错误信息缓冲区
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*device = pcap_open_live(dev_name, MAX_BYTE, 1, 512, errbuf);
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if (*device == NULL)
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{
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perror("pcap_open_live");
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exit(-1);
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}
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// 处理数据包
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libnet_t *libnet = libnet_init(LIBNET_LINK, dev_name, errbuf); // 初始化 libnet
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if (libnet == NULL)
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{
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perror("libnet_init");
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exit(-1);
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}
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return libnet; // 返回 libnet 上下文
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}
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// 处理数据包
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// 参数: 传递给回调函数的参数、数据包头部、数据包
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void process_packet(u_char *arg, const struct pcap_pkthdr *pkthdr, const u_char *packet)
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{
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// 将数据包从一个网卡发送到另一个网卡
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// 实际路由中，需要根据路由表进行路由选择
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printf("process_packet\n");
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/*
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libnet_ptag_t t; // libnet 标签: 用于标识数据包中的某一部分
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libnet_t *libnet; // libnet 上下文: 用于发送数据包
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// 根据网卡设备选择 libnet 上下文，以便发送数据包
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// 规则是: 如果是从网卡1接收到的数据包，就从网卡2发送出去
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if (arg == (u_char *)device1)
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{
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libnet = libnet_context2;
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}
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else if (arg == (u_char *)device2)
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{
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libnet = libnet_context1;
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}
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t = libnet_build_ethernet(
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((struct libnet_ethernet_hdr *)packet)->ether_dhost, // 目的MAC地址
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((struct libnet_ethernet_hdr *)packet)->ether_shost, // 源MAC地址
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((struct libnet_ethernet_hdr *)packet)->ether_type, // 以太网类型
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packet + LIBNET_ETH_H, // 负载数据(携带的数据)
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pkthdr->len - LIBNET_ETH_H, // 以太网数据包的数据部分
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libnet, // libnet 上下文
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0 // 标记
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);
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if (t == -1)
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{
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perror("libnet_build_ethernet");
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exit(-1);
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}
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// 发送数据包
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int res = libnet_write(libnet);
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if (res == -1)
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{
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perror("libnet_write");
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exit(-1);
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} */
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struct libnet_ethernet_hdr *eth_hdr = (struct libnet_ethernet_hdr *)packet;
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// 如果是IP数据包，就打印源IP地址和目的IP地址
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if (ntohs(eth_hdr->ether_type) == ETHERTYPE_IP)
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{
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struct libnet_ipv4_hdr *ip_hdr = (struct libnet_ipv4_hdr *)(packet + LIBNET_ETH_H);
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if (ip_hdr->ip_p == IPPROTO_TCP)
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{
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struct libnet_tcp_hdr *tcp_hdr = (struct libnet_tcp_hdr *)(packet + LIBNET_ETH_H + LIBNET_IPV4_H);
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printf("TCP: %s:%d -> %s:%d\n", inet_ntoa(ip_hdr->ip_src), ntohs(tcp_hdr->th_sport), inet_ntoa(ip_hdr->ip_dst), ntohs(tcp_hdr->th_dport));
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}
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else if (ip_hdr->ip_p == IPPROTO_UDP)
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{
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struct libnet_udp_hdr *udp_hdr = (struct libnet_udp_hdr *)(packet + LIBNET_ETH_H + LIBNET_IPV4_H);
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printf("UDP: %s:%d -> %s:%d\n", inet_ntoa(ip_hdr->ip_src), ntohs(udp_hdr->uh_sport), inet_ntoa(ip_hdr->ip_dst), ntohs(udp_hdr->uh_dport));
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}
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libnet_t *libnet;
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if (arg == (u_char *)device1)
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{
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libnet = libnet_context2;
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}
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else if (arg == (u_char *)device2)
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{
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libnet = libnet_context1;
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}
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libnet_ptag_t t = libnet_build_ethernet(
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eth_hdr->ether_dhost,
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eth_hdr->ether_shost,
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ETHERTYPE_IP,
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packet + LIBNET_ETH_H,
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pkthdr->len - LIBNET_ETH_H,
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libnet,
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0);
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if (t == -1)
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{
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perror("libnet_build_ethernet");
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exit(-1);
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}
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int res = libnet_write(libnet);
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if (res == -1)
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{
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perror("libnet_write");
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exit(-1);
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}
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}
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// 如果是ARP数据包，就打印源IP地址和目的IP地址
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if (ntohs(eth_hdr->ether_type) == ETHERTYPE_ARP)
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{
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struct libnet_arp_hdr *arp_hdr = (struct libnet_arp_hdr *)(packet + LIBNET_ETH_H);
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// printf("ARP: %s -> %s\n", inet_ntoa(*(struct in_addr *)arp_hdr->arp_spa), inet_ntoa(*(struct in_addr *)arp_hdr->arp_tpa));
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}
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}
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// ARP 数据报处理函数
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void process_arp_packet(const u_char *packet)
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{
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struct ether_header *eth_hdr = (struct ether_header *)packet;
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} |